Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/09/12
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1008 AM MST WED NOV 7 2012
.UPDATE...
&&
.SHORT TERM...CURRENT FORECASTS LOOKING ON TRACK...ANY UPDATES WILL
BE MINOR. LATEST MODELS INDICATING WINDS ACROSS PLAINS WILL
REMAIN BELOW CRITICAL FIRE WEATHER THRESHOLDS EVEN WITH MIXING.
.AVIATION... LATEST RUC AND HIRES MODELS INDICATING SOME SORT OF
WEAK MESOCYCLONE DEVELOPING SOUTH OF DENVER AFTER 23Z...WHICH WILL
RESULT IN WINDS SHIFTING TO THE NORTH AT THE AREA AIRPORTS. WILL
TREND TAF WINDS IN THAT DIRECTION. SPEEDS WILL BE BELOW 8 KTS.
REST OF TAF TRENDS LOOK REASONABLE.
&&
.PREV DISCUSSION... /ISSUED 410 AM MST WED NOV 7 2012/
SHORT TERM...UPPER LEVEL RIDGE AXIS AND ASSOCIATED THERMAL RIDGE
WILL SHIFT EASTWARD ACROSS THE STATE TODAY. THIS WILL BRING
UNSEASONABLY WARM TEMPERATURES WITH HIGHS PUSHING INTO THE 70S ON
THE PLAINS...60S FOOTHILLS...AND MAINLY UPPER 40S THROUGH THE
LOWER 60S IN THE MOUNTAINS. THESE READINGS WILL APPROACH BUT MOST
LIKELY NOT SURPASS RECORD HIGHS FOR TODAY...RECORD FOR DENVER IS
78 DEGREES LAST SET IN 1999. WHILE UPSTREAM WATER VAPOR IS RATHER
DRY...THE LATEST MODELS INCLUDING THE WRF SYNTHETIC IMAGERY
SUGGEST POTENTIAL FOR A NARROW WAVE CLOUD DEVELOPING RIGHT ALONG
THE FRONT RANGE THIS AFTERNOON. DONT SEE THIS BEING SIGNIFICANT
ENOUGH TO OFFER MUCH IF ANY COOLING.
WESTERLY COMPONENT INCREASES A BIT LATE THIS AFTERNOON/TONIGHT...
SO BREEZY CONDITIONS EXPECTED AT TIMES IN THE FRONT RANGE
MOUNTAINS/FOOTHILLS. THIS WILL ALSO KEEP MILD TEMPERATURES IN
PLACE OVERNIGHT RIGHT ALONG THE FRONT RANGE.
LONG TERM...THE UPPER RIDGE WILL REMAIN OVER THE CENTRAL PART OF
THE COUNTRY ON THURSDAY...THOUGH FLOW ALOFT OVER COLORADO WILL BE
TRANSITIONING TO MORE WESTERLY AND SOUTHWESTERLY. TEMPERATURES
WILL REMAIN WARM THURSDAY AND FRIDAY...BUT NOT AS WARM AS
LATER TODAY. EVEN WITH THE MODERATE SOUTHWEST FLOW ALOFT...SURFACE
CYCLOGENESIS WILL KEEP WINDS OVER NORTHEAST COLORADO LIGHT AND
POSSIBLY OUT OF THE NORTH...WHICH WILL LIMIT THE FIRE WEATHER
THREAT...IN SPITE OF THE RECENT LACK OF PRECIPITATION.
OVER THE WEEKEND...EACH OF THE MODELS CONTINUE TO AGREE ON MOVING
A STRONG UPPER TROUGH OVER THE STATE. THE TROUGH WILL BE DRIVEN BY
A NICE POOL OF COLD AIR AT 500 MB...AND Q-G DIAGNOSTICS SHOWS
THERE WILL BE QUITE A BIT OF LIFT ASSOCIATED WITH THE TROUGH. A
STRONG UPPER LEVEL JET WILL ALSO DEVELOP...ALONG WITH SURFACE
CYCLOGENISIS. PERIODS OF SNOW WILL BE POSSIBLE ACROSS THE FORECAST
AREA FROM SATURDAY MORNING THROUGH SUNDAY. COLD AIR BEHIND A
SURFACE COLD FRONT WILL ALSO MAKE FOR A COLD DAY ON SUNDAY. HIGHS
ON THE PLAINS MAY STRUGGLE TO REACH THE LOWER 30S.
THE UPPER TROUGH WILL BE MOVING EAST OF THE STATE BY SUNDAY NIGHT
WITH WEAK RIDGING EXPECTED FOR THE FIRST COUPLE DAYS OF NEXT WEEK.
TEMPERATURES SHOULD GRADUALLY MODERATE TO SEASONAL NORMALS AS
SHOWER ACTIVITY OVER THE MOUNTAINS LINGERS AND THE PLAINS ZONES
DRY OUT.
AVIATION...TYPICAL DIURNAL WIND PATTERNS EXPECTED THE NEXT 24
HOURS WITH SOUTHWEST WINDS BECOMING EASTERLY BY 17Z-19Z...THEN
TURNING BACK SOUTH/SOUTHWESTERLY 00Z-03Z AT KDEN AND KAPA. KBJC
SHOULD TURN MORE WESTERLY TONIGHT WITH A FEW GUSTS AROUND 20KTS
AFTER 03Z. ONLY SCT HIGH CLOUDS THIS AFTERNOON/EVENING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....DANKERS
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS ALBANY NY
1036 AM EST WED NOV 7 2012
.SYNOPSIS...
A NOR EASTER STORM WILL MOVE FROM OFF THE JERSEY SHORE TODAY TO NEAR
CAPE COD TOMORROW...ALLOWING FOR SOME LIGHT SNOW AND RAIN TO THE
REGION...ESPECIALLY FOR AREAS TO THE SOUTH AND EAST OF ALBANY.
BEHIND THIS STORM...MILDER AND DRY CONDITIONS WILL RETURN FOR THE
UPCOMING WEEKEND AND FOR EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 1030 AM EST...THE LEADING EDGE OF PRECIP CONTINUES TO
ADVANCE WNW...INTO SW CT AND WESTERN LI. 12Z UA SOUNDINGS INDICATE
AN ABUNDANCE OF DRY AIR IN THE MID LEVELS...HOWEVER THUS FAR THE
PRECIP HAS BEEN ADVANCING SEEMINGLY UNIMPEDED BY THE DRY AIR.
STRONG FORCING/FGEN TO THE N AND W OF INTENSIFYING STORM CENTER
HAS CREATED BANDING OF PRECIP...AND SOME OF THESE BANDS WILL
LIKELY REACH BERKSHIRE/LITCHFIELD COS BY EARLY AFTERNOON...AS WELL
AS PORTIONS OF THE MID HUDSON VALLEY. LATEST RUC 13 ALSO INDICATES
POTENTIAL FOR BANDS OF MODERATE OR LOCALLY HEAVY PRECIP TO REACH
THESE AREAS BY MID TO LATE AFTERNOON. THE AFOREMENTIONED DRY MID
LEVEL AIR SHOULD ALLOW FOR SIGNIFICANT WET BULB COOLING FAVORABLE
FOR MAINLY SNOW ONCE PRECIP INTENSITY INCREASES. SO...ALTHOUGH
NO ADVISORIES ARE INDICATED AT THIS TIME...IT IS QUITE POSSIBLE
THAT WITH THE MIDDAY UPDATE...THAT WINTER WEATHER ADVISORIES WILL
BE ISSUED FOR BERKSHIRES/LITCHFIELD COS...AND PORTIONS OF THE MID
HUDSON VALLEY REGION...WITH AN INCREASE IN SNOW ACCUM TO THE 3-6
INCH RANGE. THIS IS SUPPORTED BY THE LATEST 12Z/NAM...AND RUC13
OUTPUT. WILL AWAIT 12Z/GFS DATA BEFORE MAKING FINAL MIDDAY
DECISIONS ON ISSUING ANY ADVISORIES AND INCREASING SNOW TOTALS.
OTHERWISE...TEMPS SHOULD ONLY RISE A FEW DEGREES TODAY...GENERALLY
ONLY INTO THE MID 30S...AND MAY ACTUALLY FALL ACROSS SOUTHERN
AREAS DURING THE AFTERNOON AS PRECIP AND ENSUING WET BULB COOLING
COMMENCE. MODEL SOUNDINGS SHOW THAT PRECIP SHOULD REMAIN AS ALL
SNOW TONIGHT...HOWEVER...IF THE TRACK IS SLIGHTLY FURTHER
WEST...THEN A WARM NOSE ALOFT COULD ALLOW FOR A BRIEF PERIOD OF
SOME IP/FZRA FOR FAR SOUTHEASTERN PORTIONS OF THE REGION FOR THE
LATE TONIGHT. SINCE CONFIDENCE IN THIS OCCURRING WAS LOW...THIS
WAS NOT INCLUDED IN THE FORECAST AT THIS TIME. TEMPS OVERNIGHT
WILL GENERALLY BE STEADY IN THE UPPER 20S TO LOW 30S...ALTHOUGH
TEMPS WILL DROP INTO THE LOW 20S IN THE ADIRONDACKS WHERE PRECIP
IS NOT EXPECTED.
SOME PRECIP WILL INITIALLY BE LOST AS VIRGA DUE TO THE DRY AIR
MASS IN PLACE. WE GENERALLY FOLLOWED THE 00 UTC GFS/ECMWF WHICH
WERE VERY SIMILAR FOR QPF ACROSS THE REGION. THE 00 UTC GEFS
PLUMES SHOWED LITTLE SPREAD...HOWEVER...THE 03 UTC SREF PLUMES DID
CONTINUE TO SHOW QUITE A VARIETY OF QPF RANGE ACROSS THE AREA. IN
OUR FORECAST...WE WENT WITH LIQUID EQUIVALENT QPF THROUGH TONIGHT
RANGING FROM ZERO ACROSS THE ADIRONDACKS...A FEW HUNDREDTHS IN THE
MOHAWK VALLEY...UP TO A TENTH OF AN INCH FOR THE CAPITAL REGION
AND LAKE GEORGE SARATOGA REGION...AND TWO TO FOUR TENTHS FOR THE
CATSKILLS...MID HUDSON VALLEY...TACONICS...AND WESTERN NEW
ENGLAND. THE BEST SNOW RATIOS WILL BE ACROSS THE HIGHER
TERRAIN DUE TO SLIGHTLY COLDER AIR...AND VALLEYS AREAS MAY HAVE A
LITTLE TROUBLE ACCUMULATING SNOW AT FIRST DUE TO THE RELATIVELY
WARM AND POSSIBLY WET GROUND. BASICALLY...AROUND AN INCH OF SNOW IS
EXPECTED FOR THE CAPITAL REGION...ONE TO THREE INCHES FOR THE MID
HUDSON VALLEY...AND TWO TO FOUR INCHES FOR THE HIGHER TERRAIN OF
THE CATSKILLS...TACONICS...AND WESTERN NEW ENGLAND THROUGH TONIGHT.
THIS FALLS SHORT OF WINTER WEATHER ADVISORY CRITERIA /FOUR INCHES
AVERAGE WOULD BE NEEDED/ SO NO HEADLINES ARE BEING ISSUED AT THIS
TIME...BUT MODEL QPF WILL CONTINUE TO MONITORED CLOSELY...ESP
CONSIDERING THE SPREAD IN THE 03 UTC SREF PLUMES.
WITH THE DEVELOPING STORM...WINDS ALOFT WILL BE STRONG...ALLOWING
FOR SOME BREEZY CONDITIONS FOR THE MID HUDSON VALLEY AND NW CT. WE
WILL HOLD OFF ON A WIND ADVISORY AT THIS TIME...BUT THE GFS/NAM DO
SHOW 40-50 KTS AT AROUND 2-3 KFT OVER NW CT DURING THE LATE
MORNING/EARLY AFTN TODAY. SOME GUSTS OF 30-40 MPH ARE POSSIBLE FOR
DUTCHESS/LITCHFIELD COUNTIES AND THIS HAS BEEN INCLUDED IN THE
FORECAST...ESP FOR THE HIGHER TERRAIN. THIS FALLS JUST SHORT OF
CRITERIA FOR A WIND ADVISORY SO NO WIND HEADLINES ARE BEING
ISSUED...BUT IF WINDS ALOFT ARE STRONGER THAN CURRENTLY MODELED OR
IF BETTER MIXING OCCURS...THEN A SHORT FUSE WIND ADVISORY COULD BE
NEEDED FOR FAR SOUTHEASTERN PARTS OF THE CWA.
BY THURSDAY...PRECIP WILL BE ENDING IN THE MORNING HOURS FROM WEST
TO EAST...AND LITTLE TO NO ADDITIONAL SNOW ACCUMULATION WILL
OCCUR. WITH THE PRECIP LIGHTENING UP AND ICE NUCLEI DECREASING IN
THE CLOUD DECK...THE PRECIP MAY END AS SOME LIGHT DRIZZLE OR
RAIN SHOWERS...ESP FOR VALLEY AREAS. IF SFC TEMPS REMAIN BELOW
FREEZING...THIS COULD ALLOW FOR A LITTLE FZDZ POSSIBLY...BUT
CONFIDENCE IN THIS HAPPENING IS RATHER LOW AT THIS TIME. BY
AFTN...MOST AREAS SHOULD BE DRY WITH DECREASING AMOUNTS OF
CLOUDINESS AND TEMPS RISING. MAX TEMPS ON THURSDAY AFTN WILL
GENERALLY BE IN THE 30S TO LOW 40S.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
THE MODEL GUIDANCE REMAINS IN GOOD AGREEMENT THAT THE LONGWAVE
PATTERN WILL CHANGE ACROSS THE CONUS AS WE HEAD INTO THE WEEKEND.
THE PERSIST TROUGH OVER THE EASTERN UNITED STATES WILL BE REPLACED
BY A RIDGE AND THE RIDGE OVER THE WESTERN UNITED STATES WILL BE
REPLACED BY A DIGGING TROUGH.
ACROSS OUR REGION...HIGH PRESSURE WILL BUILD IN AT THE SURFACE WITH
HEIGHTS RISING ALOFT. THIS WILL RESULT IN MODERATING TEMPERATURES
WITH NEAR NORMAL READINGS EXPECTED FOR SATURDAY.
A LARGE LOW PRESSURE SYSTEM ASSOCIATED WITH THE TROUGH MOVING INTO
THE CENTRAL PLAINS WILL MOVE NORTHEASTWARD INTO THE GREAT LAKES
REGION SATURDAY NIGHT. A WARM FRONT EXTENDING WELL EAST FROM THE LOW
SHOULD GRAZE THE FORECAST AREA RESULTING IN MAINLY AN INCREASE IN
CLOUD COVER.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THE UPPER TROUGH IS EXPECTED TO DAMPEN AS IT ENCOUNTERS THE RIDGE
OVER THE EASTERN UNITED STATES. ITS ASSOCIATED LOW PRESSURE SYSTEM
IS EXPECTED TO MOVE INTO EASTERN CANADA EARLY NEXT WEEK AND DRAG ITS
COLD FRONT ACROSS THE REGION BRINGING THE AREA OUR NEXT WIDESPREAD
CHANCES FOR PRECIPITATION. THE MODEL GUIDANCE IS IN GOOD AGREEMENT
THAT COLD FRONTAL PASSAGE SHOULD OCCUR BETWEEN 06Z-18Z TUESDAY.
ABOVE NORMAL TEMPERATURES ARE EXPECTED TO CLOSE OUT THE WEEKEND AND
START NEXT WEEK AS THE REGION WILL BE IN THE WARM SECTOR OF THE
APPROACHING LOW PRESSURE SYSTEM WITH BROAD SOUTHWEST FLOW ACROSS THE
REGION.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
LOW PRESSURE OFF THE MID ATLANTIC COAST WILL CONTINUE TO DEEPEN AS
IT MOVES NORTHWARD TODAY WHILE REMAINING OFFSHORE. THIS COASTAL LOW
IS EXPECTED TO PASS SOUTH AND EAST OF LONG ISLAND LATE TONIGHT AND
TO THE SOUTHEAST OF CAPE COD THURSDAY.
LOW LEVEL CLOUDS HAVE DEVELOPED UNDER THE CIRRUS SHIELD ACROSS MID
HUDSON VALLEY EASTWARD ACROSS SOUTHERN NEW ENGLAND. MAINLY VFR
CONDITIONS ARE EXPECTED THIS MORNING WITH MVFR CIGS ACROSS THE
BERKSHIRES.
CLOUDS WILL LOWER AS THE PRECIPITATION ASSOCIATED WITH THE COAST LOW
MOVES INTO AREA THIS AFTERNOON. KPOU AND KPSF WILL BE IMPACTED THE
MOST WITH ACCUMULATING SNOWS EXPECTED THIS EVENING AND OVERNIGHT.
INITIALLY BOUNDARY LAYER CONDITIONS MAY BE WARM ENOUGH FOR RAIN TO
MIX IN WITH THE SNOW CHANGEOVER TO ALL SNOW BY LATE AFTERNOON WITH
CONDITIONS LOWERING TO IFR.
KALB WILL BE ON THE NORTHERN EDGE OF THE PRECIPITATION SHIELD.
CONDITIONS ARE NOT EXPECTED TO LOWER TO MVFR UNTIL THIS EVENING WHEN
A PERIOD OF LIGHT SNOW IS EXPECTED INTO THE EARLY MORNING HOURS.
VFR CONDITIONS ARE EXPECTED AT KGFL UNTIL AT LEAST MIDNIGHT THEN
MVFR IS POSSIBLE ALONG WITH SOME LIGHT SNOW FOR A PERIOD INTO THE
EARLY MORNING HOURS.
NORTHERLY WINDS WILL DEVELOP AFTER SUNRISE WITH WINDS BECOMING GUSTY
AT KPOU...KPSF AND KALB WITH GUSTS UP TO AROUND 20 KNOTS DURING THE
AFTERNOON.
OUTLOOK...
THU...BRISK. VFR-MVFR. CHC OF SNOW CHANGING TO RAIN AT KPOU...KPSF
AND KALB IN THE MORNING WITH CHANCES DECREASING IN THE AFTERNOON.
THE BETTER CHANCES WILL BE AT KPOU AND KPSF.
THU NIGHT-SUN...VFR. NO SIG WX.
&&
.HYDROLOGY...
NO HYDROLOGIC ISSUES ARE EXPECTED ACROSS THE HSA THROUGH THE
WEEKEND.
A COASTAL STORM WILL BRUSH THE REGION FOR TODAY INTO TOMORROW.
PRECIPITATION MAY INITIALLY START AS LIGHT RAIN IN VALLEY
AREAS LATE TOADY...BUT IT QUICKLY TRANSITION TO SNOW FOR TONIGHT.
THE PRECIPITATION MAY END AS SOME LIGHT RAIN AND SNOW SHOWERS FOR
THURSDAY MORNING.
TOTAL LIQUID EQUIVALENT WILL RANGE FROM AROUND UNDER A TENTH OF AN
INCH FROM THE CAPITAL REGION NORTH AND WEST...TO UP TO FOUR TENTHS OF
AN INCH FOR THE MID HUDSON VALLEY...EASTERN CATSKILLS...TACONICS...AND
WESTERN NEW ENGLAND. WITH THE MAJORITY OF THE PRECIPITATION
FALLING AS SNOW...THERE SHOULD BE LITTLE RESPONSE ON AREA RIVERS
AND STREAMS. THIS SHOULD ALLOW FOR RIVER AND STREAM LEVELS TO HOLD
NEARLY STEADY THROUGH THE WEEKEND.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...KL/FRUGIS
SHORT TERM...IAA
LONG TERM...IAA
AVIATION...IAA
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
216 PM EST Wed Nov 7 2012
...First frost possible Friday morning...
.NEAR TERM [Through Tonight]...
The upper level longwave pattern remains similar to that of
yesterday based on the 18z CONUS NAM/regional RAP analysis. Broad
deep-layer ridging covers the western half of the country, while
several embedded impulses have expanded the spatial scale of the
eastern U.S. trough. At the surface, the main feature is the
Nor`easter centered due east of Maryland in the western Atlantic.
Further upstream, a series of low pressure troughs generated by
their upper level counterparts have created areas of showers across
northern and central Georgia and Alabama. Expect these showers to
continue as the surface features move south. Showers that do enter
our forecast area should be rather light, most likely to impact SE
AL and S Georgia this afternoon, weakening and spreading offshore
overnight where they may pick up a bit more steam over the more
unstable Gulf waters. The greatest impact thus far today has been
the lingering cloud cover, holding temperatures in the upper 50s to
low 60s most of the day across south central Georgia. Elsewhere,
temperatures have managed to climb into the lower to middle 60s
under partly cloudy skies.
In addition to the passing light showers and cloud cover overnight,
winds are expected to not go completely calm, but lighter winds will
combine with clearing skies to yield another chilly night. Expect
temperatures area wide to fall into the upper 30s, with middle 40s
more likely nearer to the coast.
&&
.SHORT TERM [Thursday Through Saturday]...
The last in a recent series of potent 500 mb short waves will be
exiting to our east Thursday morning, followed by rapidly-building
deep layer ridging Friday and Saturday. After one more relatively
cool day (with highs Thursday in the mid to upper 60s and lows
Friday in the mid to upper 30s), a warming trend will commence
(especially during the afternoons, as lows can still get rather cool
with the increasingly longer nights, light winds, and a dry
airmass). Highs on Friday and Saturday will be in the 70s, with lows
on Saturday in the upper 30s to lower 40s. Friday morning appears to
be our best chance (with the current "cold spell") at this
season`s first frost. This will only be the case in the normally
coldest inland locations- the open fields away from the cities.
&&
.LONG TERM [Saturday Night through Wednesday]...
The deep layer ridge over the Southeast on Sunday will break down as
a weakening cold front moves southeast across the forecast area
Monday night and Tuesday. The GFS and ECMWF both show this system
getting "stretched" out in the deep layer moisture/QPF fields, as
the associated 500 mb height falls remain north of our region. With
this weakening, the max PoP for is only 30%. The front is likely to
stall across central FL Wednesday as a frontal wave begins to
develop in the western Gulf of Mexico, so this may not be a "clean"
frontal passage. The above-average temperatures (especially daytime
highs- which will be well into the 70s) ahead of the cold front
Sunday and Monday will give wave to near average temperatures behind
the front Tuesday and Wednesday.
&&
.AVIATION [Beginning 19Z Wednesday]...
Cloud cover remains, however, all sites reside under VFR conditions
at this time. Expect low/mid level clouds to spread south and affect
all terminals through the rest of the afternoon and evening, but
remain VFR through the TAF. Tomorrow, clear skies, calm winds, and
VFR conditions will prevail.
&&
.MARINE...
Winds and seas will be at exercise caution levels tonight, then drop
below these levels quickly Thursday morning. They will remain at
relatively low levels until Saturday afternoon or evening, when a period
of exercise caution to possible even advisory levels begins,
lasting through Monday.
&&
.FIRE WEATHER...
There are no fire weather concerns on Thursday as relative humidity
values will likely remain above critical levels. On Friday however,
humidity values will fall to below 25 percent area wide. Any
watch/warning decisions will be based upon future ERC forecast for
Florida. Winds will not support advisories for Georgia, and RH
duration requirements will not be met in Alabama. The dry conditions
will continue through Saturday before creeping up above critical
levels by Sunday.
&&
.HYDROLOGY...
The recent rain (Monday night-early Tuesday) had little impact on
local river stages, as they remained well below flood stage. The
upcoming rain event (Monday night and Tuesday) is expected to be
too light and/or localized to have any significant impact on the
river stages.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 37 68 34 73 38 / 10 0 0 0 0
Panama City 45 67 45 72 49 / 20 0 0 0 0
Dothan 38 66 37 72 42 / 10 0 0 0 0
Albany 38 67 36 73 39 / 10 0 0 0 0
Valdosta 38 66 37 71 39 / 10 0 0 0 0
Cross City 38 69 35 73 38 / 10 0 0 0 0
Apalachicola 43 65 45 70 49 / 20 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM/AVIATION/FIRE WX...Harrigan
SHORT TERM/LONG TERM/MARINE/HYDROLOGY...Fournier
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
155 PM CST WED NOV 7 2012
.DISCUSSION...
1115 AM CST
NOT MUCH CHANGE IN FORECAST. LIGHT RAIN AND DRIZZLE HAS ENDED AS
SHORT WAVE CONTINUES TO MOVE SOUTHEAST AWAY FROM THE AREA. WITH WEAK
PRESSURE PATTERN AND LIGHT WINDS...DON`T SEE MUCH PROSPECT OF ANY
CLEARING. SOME DRIER AIR NOTED OVER MI AND IN BUT ADVECTION IS VERY
WEAK. SOME PARTIAL SUN OVER NORTHWEST IN AND FAR EASTERN IL
POSSIBLE. CLEARING WILL BE SLOW TONIGHT AND ANYPLACE THAT CLEARS
WILL LIKELY FOG IN LATER TONIGHT AND THURSDAY MORNING. WITH OVERCAST
CONDITIONS TEMPERATURES WON`T MOVE MUCH THE REST OF TODAY.
ALLSOPP/CASTRO
PREVIOUS DISCUSSION...
322 AM CST
THE IMMEDIATE FORECAST CHALLENGES ARE LINGERING DRIZZLE/LIGHT
RAIN AND ALSO CLOUDS...WITH THE LATTER REMAINING POTENTIALLY INTO
THURSDAY. THEN ATTENTION TURNS TO WHAT DEGREE OF WARM-UP WILL BE
REALIZED AS THE PATTERN BECOMES MORE AMPLIFIED...PROVIDING THE
FINAL CHALLENGE OF PRECIP CHANCES THIS WEEKEND INTO EARLY NEXT
WEEK.
A BROAD UPPER TROUGH WITH DISTINCT POTENT SHORT WAVES HAS EVOLVED
OVER THE EASTERN U.S. FROM LATE YESTERDAY AFTERNOON INTO THIS
MORNING. FINAL SHORT WAVE IS PROGRESSING SOUTHEASTWARD ACROSS
CENTRAL IL EARLY THIS MORNING. STRONG 120+ KNOT NORTH-TO-SOUTH JET
IS LINED UP OVER THE MISSISSIPPI RIVER VALLEY AND WILL HELP TO
PROGRESS THIS SOUTH. THE AREA WILL REMAIN ON THE CYCLONIC SIDE OF
THIS STRONG JET THROUGH TODAY...AND ASSOCIATED MID-LEVEL SHEAR
VORTICITY WILL NOT OFFER MUCH FOR SUPPRESSION TO HELP SCOUR
CLOUDS. AND THOSE CLOUDS ARE WIDESPREAD ON THE EARLY MORNING
11-3.9 MICRON CHANNEL. LAST NIGHTS RAOBS AND EARLY MORNING AMDAR
SOUNDINGS INDICATE THE MOISTURE TO BE SIGNIFICANTLY
DEEP...GENERALLY AROUND 15KFT. IN ADDITION...WITH THE BAGGY LOW-
LEVEL TROUGH DRAPED FROM WI THROUGH THE LOWER APPALACHIANS THIS
MORNING...THE WIND FLOW IS SOMEWHAT LIGHT AND CERTAINLY NOT
ALLOWING FOR ANY DRY AIR ADVECTION INTO THE AREA. MOST MODELS SEEM
TOO QUICK TO BREAK UP A LOT OF THE CLOUDS IN THEIR HUMIDITY
SOLUTIONS...BUT THEY DO AGREE ON A LIGHT WIND FIELD BY AFTERNOON
AND EVENING...NOT SUPPORTIVE OF DISSIPATION OF SUCH A DEEP CLOUD
LAYER. SO FAVOR THE SLOWER NAM SCOURING AND HAVE INCREASED THE
DURATION OF THE CLOUDS BY QUITE A WHILE...EXTENDING THEM INTO
TONIGHT FOR MOST PLACES. SOUTHWEST WINDS BEGIN TO KICK IN ALOFT
TOWARD DAYBREAK THU AND INCREASE THEREAFTER...WHICH SHOULD ALLOW
FOR THE LINGERING CLOUDS TO SCATTER AND ADVECT OFF TO THE
NORTHEAST THROUGHOUT THURSDAY MORNING.
ANY PRECIPITATION FOR TODAY SHOULD MAINLY BE CONFINED TO THIS
MORNING. CONTINUED GENTLE ISENTROPIC ASCENT ON THE 280K LAYER IS
ANALYZED BY THE RAP MODEL EXACTLY WHERE RADAR DEPICTS DRIZZLE AND
LIGHT RAIN ACROSS NE IL AND NW IN EARLY THIS MORNING. THIS SUPPORT
FADES SLOWLY THROUGH THE MORNING...AND NOT REALLY UNTIL LATE
MORNING AT THAT. MULTIPLE SHORT TERM MODELS SUPPORT THIS DOWNWARD
TREND ON REFLECTIVITY. SO HAVE SOME MENTION FOR DRIZZLE WITH
POCKETS OF LIGHT RAIN.
TEMPERATURES TODAY SHOULD STRUGGLE TO CLIMB MUCH. THE CLOUDS WITH
THE LOW ANGLE SUN AT THIS TIME OF YEAR SHOULD ALLOW FOR A DIURNAL
SPREAD FAR LOWER THAN THE NORMAL 16-18 DEGREES THIS TIME OF YEAR.
THIS MORNING ALONE PLACES MAY ONLY CLIMB A COUPLE DEGREES AT MOST.
THE TEMPERATURES TONIGHT ARE A BIG CHALLENGE AND DEPENDING ON
CLOUD COVER COULD VARY UP TO 15 DEGREES OR SO. HAVE TRENDED
WARMER FOR AREAS WHERE WE THINK CLOUDS WILL HANG ON THE LONGEST.
FAR WESTERN AND SOUTHERN AREAS SEEM THE MOST PROBABLE TO
POTENTIALLY CLEAR. WITH RAIN FROM LAST NIGHT AND THEN A COOL HIGH
TEMPERATURE TODAY...SUCH CLEARING WOULD VERY LIKELY FAVOR FOG AND
EVEN DENSE FOG AT THAT. HAVE ADDED THE DENSE POSSIBILITY ONTO THE
GOING FOG WORDING FOR TONIGHT.
WARM AIR ADVECTION THEN ENSUES THURSDAY INTO THE WEEKEND AS THE
CURRENT UPPER LOW OVER THE GULF OF ALASKA BEGINS TO FURTHER A
LONG WAVE TROUGH ACROSS WESTERN NORTH AMERICA. EACH DAY
PROGRESSIVELY WARMS ACROSS THE FORECAST AREA THROUGH
SATURDAY...AND POTENTIALLY EVEN INTO SUNDAY. THE LEAD PUSH OF
ELEVATED MOISTURE AND MORE STOUT WARM AIR ADVECTION ARRIVES FRIDAY
NIGHT INTO EARLY SATURDAY ON A LEAD SHORT WAVE. THICKNESS
DIFLUENCE AND SURPRISINGLY ELEVATED INSTABILITY ARE REASONABLE
WITH THIS FOR SOME SHOWERS AND EVEN THUNDER...BUT FORECAST DEEP
MOISTURE IS LACKING. THE GOING PLACEMENT OF LOW CHANCE POPS FOR
FRIDAY NIGHT INTO SATURDAY SEEMS VERY GOOD TO CAPTURE THESE
POSSIBILITIES...AND HAVE IN GENERAL MADE FEW CHANGES THERE.
TEMPERATURES ON SATURDAY LOOK TO BE QUITE MILD WITH THE ONLY FLY
IN THE OINTMENT SEEMINGLY IF CLOUDS EARLY HOLD THINGS BACK. BREEZY
SOUTHERLY WINDS WILL ENSUE AS SURFACE CYCLOGENESIS OCCURS FROM THE
CENTRAL PLAINS NORTHEASTWARD. THE 850 MB TEMPS FORECAST BY A
07.00Z EC/GFS BLEND ARE +14C. GIVEN JUST 850MB TEMPS IN EXCESS OF
10C THIS TIME OF YEAR...LOCAL RESEARCH CLIMATOLOGY FOR CHICAGO
SUPPORTS A MEDIAN HIGH OF 67 WITH 70 BEING THE UPPER 25TH
PERCENTILE. SO THE 70 DEGREE MARK IS NOT OUT OF THE QUESTION
ESPECIALLY IF WE START THE DAY SUNNY. SUNDAY IS A BIT MORE
CHALLENGING BUT WILL HAVE AN EVEN WARM STARTING POINT...LIKELY
AROUND 50 DEGREES. SO A FORECAST OF AT LEAST LOWER TO MID 60S
AREA WIDE ON BOTH WEEKEND DAYS HAS PRETTY HIGH CONFIDENCE
ESPECIALLY FOR THIS MANY DAYS OUT THIS TIME OF YEAR.
THE PRECIP CHANCES APPEAR BEST ALONG THE COLD FRONT SUNDAY
AFTERNOON AND NIGHT...WITH THAT FRONTAL TIMING BEING IN GOOD
AGREEMENT ON THE LONG RANGE GUIDANCE. STILL...CANNOT RULE OUT
EARLIER ACTIVITY AS MENTIONED ABOVE AS EARLY AS FRIDAY NIGHT...BUT
EVEN ON SATURDAY NIGHT THE LOW-LEVEL JET WILL BE STRONG ACROSS THE
AREA. HAVE CONTINUED TO INCREASE THE RAIN LIKELIHOOD ON SUNDAY AND
SUNDAY NIGHT...WITH CATEGORICAL POPS NOW IN THE FORECAST. SOME
THUNDER CERTAINLY REMAINS PLAUSIBLE WITH SUCH A DYNAMIC
PROJECTION. COLDER AND THEN DRIER AIR LOOKS TO WRAP IN ON
MONDAY...AND IT WILL BE A BIT OF A RACE TO SEE IF THAT COLDER AIR
WILL CATCH UP TO THE FORCING TO PROVIDE SOME SNOW ON THE BACK
SIDE. AT THIS TIME...THE FORECAST DOES CALL FOR FALLING
TEMPERATURES ON MONDAY WITH NORTHWEST WINDS INCREASING.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* MVFR VSBYS LATE EVENING AND OVERNIGHT.
* SOME POTENTIAL FOR LIFR CIGS AND OR VSBYS LATE NIGHT INTO THU
MORNING.
TRS
//DISCUSSION...UPDATED 18Z...
UPPER LOW THAT WAS OVER NORTHWEST IL LATE LAST NIGHT HAS
QUICKLY MOVED SOUTH-SOUTHEAST TO WESTERN TN AT MIDDAY TAKING
THE ASSOCIATED MID AND LOWER LEVEL CIRCULATIONS WITH IT...AS
WELL AS THE LIGHT RAIN AND DRIZZLE.
A WEAK SURFACE TROUGH EXTENDING FROM A WEAK SURFACE LOW IN
EASTERN TN NORTHWESTWARD ACROSS NORTHWESTERN IN AND FAR
NORTHEASTERN IL...AND NORTHWARD OVER EASTERN WI. THE WEAK WEAK
PRESSURE FIELD ACROSS THE REGION HAS AND CONTINUES TO RESULT IN
LIGHT WINDS...FAVORING A GENERALLY EAST-NORTHEAST TO NORTHEAST
LOW LEVEL FLOW EAST OF THE TROUGH AXIS...AND A NORTH TO NORTH-
NORTHWEST FLOW TO THE WEST. LOCAL WINDS TO BECOME EVEN LIGHTER
OR NIL TONIGHT AS A WEAK RIDGE OF HIGH PRESSURE OVER MN...
NORTHWESTERN IA...SOUTHEASTERN NE AND ON TO EAST TX MOVES E
ACROSS TO THE CENTRAL GREAT LAKES...LOWER OH VALLEY...AND LOWER
MS VALLEY BY 08.12Z. AFTER SUNRISE THU SOUTH-SOUTHWEST TO
SOUTHWEST WINDS WILL SET IN OVER THE LOCAL AREA ON THE WEST SIDE
OF THE RIDGE AXIS.
LOWER SURFACE DEW POINTS OVER LOWER MI AND NORTHEASTERN IN HAVE
BEEN ADVECTING WESTWARD TOWARD THE LOCAL AREA THOUGH ONLY VERY
SLOWLY GIVEN THE LIGHT LOW LEVEL WINDS. NONE THEN LESS...CLEARING
OF STRATUS AND STRATOCUMULUS HAS MADE IT AS FAR AS THE SOUTHERN
TIP OF LAKE MI AND PORTIONS OF NORTHWEST IN WITH FURTHER CLEARING
SLOWLY WORKING INTO FAR NORTHEAST IL LATE AFTERNOON/EARLY EVENING.
CLEARING ALSO EXPECTED TO MOVE IN FROM THE SOUTHWEST AS THE SOUTH-
SOUTHWEST TO SOUTHWEST LOW LEVEL FLOW GETS ESTABLISHED OVERNIGHT
AS THE RIDGE PASSES OVERHEAD.
WITH MOIST GROUND FOR EARLIER RAIN AND DRIZZLE AND LITTLE TO NO
SUNSHINE TO DRY THE SURFACE...POTENTIAL FOR AREAS OF DENSE FOG TO
DEVELOP TONIGHT AS CLEAR/CLEARING SKY...LIGHT TO NIL WINDS AND
MOIST SURFACE AND BOUNDARY LAYER TRAPPED UNDER SHALLOW SURFACE
BASED INVERSION WILL BE PRESENT. A COUPLE COMPLICATING FACTORS IN
DETERMINING OF DENSE FOG WILL FORM IS HOW QUICKLY THE SURFACE AND
LOW LEVEL FLOW ON THE BACK SIDE OF THE HIGH PRESSURE RIDGE
ESTABLISHES ITSELF...AND HOW QUICKLY CIRRUS CLOUDS SPILLING OVER
AND UPPER RIDGE TO THE WEST SPREAD OVER THE LOCAL AREA.
IF SOME FLOW AND THUS MIXING OCCURS IN THE BOUNDARY LAYER
OVERNIGHT THEN A LOW STRATUS DECK WOULD BE FAVORED OVER
AREAS/WIDESPREAD DENSE FOG...WHILE ARRIVAL OF CIRRUS OVER THE
LOCAL AREA DURING THE NIGHT WOULD LIMIT RADIATIONAL COOLING OF
THE SURFACE AND THE STRENGTH OF THE SURFACE BASED INVERSION
AND DISCOURAGE DENSE FOG. MODELS SUGGEST THAT BOTH A WEAK RETURN
LOW LEVEL FLOW AND AN INCREASE IN HIGH LEVEL CLOUDS WILL OCCUR
OVERNIGHT SO HAVE OPTED TO CONTINUE WITH THE IDEA OF NO DENSE FOG
OR LOW STRATUS DEVELOPMENT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN REMAINING VFR REST OF AFTERNOON INTO EARLY
EVENING.
* HIGH CONFIDENCE IN WINDS REMAINING AT OR BELOW 6 KT THIS
AFTERNOON AND TONIGHT.
* MODERATE CONFIDENCE IN SKY CONDITION/CEILING AND VISIBILITY
FORECASTS FOR LATE NIGHT THROUGH SUNRISE THU.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...SLIGHT CHANCE SHRA LATE.
SATURDAY...CHANCE RA.
SUNDAY...LIKELY SHRA WITH CHC TSRA. MVFR/IFR POSSIBLE.
MONDAY...CHC RAIN CHANGING TO SNOW. MVFR/IFR POSSIBLE.
TUESDAY...VFR.
KREIN
&&
.MARINE...
300 AM CST
A WEAK TROUGH OF LOW PRESSURE OVER ILLINOIS THROUGH THE WESTERN
GREAT LAKES COMBINED WITH HIGH PRESSURE OVER SOUTHEASTERN CANADA
HAS GENERATED 10 TO 20 KT SOUTHEAST WINDS. WINDS WILL WEAKEN
TONIGHT AS A RIDGE OF HIGH PRESSURE OF BUILDS EASTWARD TO THE
WESTERN GREAT LAKES. MEANWHILE...LOW PRESSURE IS FORECAST TO
DEVELOP OVER THE CENTRAL PLAINS FRIDAY NIGHT AND TRACK NORTHEAST
TO WESTERN LAKE SUPERIOR BY SUNDAY MORNING. A SOUTHERLY PRESSURE
GRADIENT WILL STRENGTHEN OVER THE LAKE AS THE LOW TRACKS
NORTHEASTWARD...WITH SOUTH WINDS INCREASING TO 15 TO 25 KT FOR
THURSDAY AND FRIDAY. WINDS SHOULD STRENGTHEN AT LEAST 30KT FOR
SATURDAY THROUGH EARLY SUNDAY AS THE LOW INTENSIFIES SOME WHILE
TRACKING
THROUGH THE UPPER MISSISSIPPI VALLEY. THERE IS A CHANCE FOR SOUTH
GALES DURING THIS PERIOD. BY LATE SUNDAY...THE LOW WILL TRACK TO
JAMES BAY WHILE DRAGGING A STRONG COLD FRONT ACROSS THE
LAKE...BRINGING A QUICK SHIFT TO NORTHWESTERLY WINDS AND A RAPID
INFLUX OF MUCH COLDER AIR.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1246 PM CST WED NOV 7 2012
.DISCUSSION...
1115 AM CST
NOT MUCH CHANGE IN FORECAST. LIGHT RAIN AND DRIZZLE HAS ENDED AS
SHORT WAVE CONTINUES TO MOVE SOUTHEAST AWAY FROM THE AREA. WITH WEAK
PRESSURE PATTERN AND LIGHT WINDS...DON`T SEE MUCH PROSPECT OF ANY
CLEARING. SOME DRIER AIR NOTED OVER MI AND IN BUT ADVECTION IS VERY
WEAK. SOME PARTIAL SUN OVER NORTHWEST IN AND FAR EASTERN IL
POSSIBLE. CLEARING WILL BE SLOW TONIGHT AND ANYPLACE THAT CLEARS
WILL LIKELY FOG IN LATER TONIGHT AND THURSDAY MORNING. WITH OVERCAST
CONDITIONS TEMPERATURES WON`T MOVE MUCH THE REST OF TODAY.
ALLSOPP/CASTRO
PREVIOUS DISCUSSION...
322 AM CST
THE IMMEDIATE FORECAST CHALLENGES ARE LINGERING DRIZZLE/LIGHT
RAIN AND ALSO CLOUDS...WITH THE LATTER REMAINING POTENTIALLY INTO
THURSDAY. THEN ATTENTION TURNS TO WHAT DEGREE OF WARM-UP WILL BE
REALIZED AS THE PATTERN BECOMES MORE AMPLIFIED...PROVIDING THE
FINAL CHALLENGE OF PRECIP CHANCES THIS WEEKEND INTO EARLY NEXT
WEEK.
A BROAD UPPER TROUGH WITH DISTINCT POTENT SHORT WAVES HAS EVOLVED
OVER THE EASTERN U.S. FROM LATE YESTERDAY AFTERNOON INTO THIS
MORNING. FINAL SHORT WAVE IS PROGRESSING SOUTHEASTWARD ACROSS
CENTRAL IL EARLY THIS MORNING. STRONG 120+ KNOT NORTH-TO-SOUTH JET
IS LINED UP OVER THE MISSISSIPPI RIVER VALLEY AND WILL HELP TO
PROGRESS THIS SOUTH. THE AREA WILL REMAIN ON THE CYCLONIC SIDE OF
THIS STRONG JET THROUGH TODAY...AND ASSOCIATED MID-LEVEL SHEAR
VORTICITY WILL NOT OFFER MUCH FOR SUPPRESSION TO HELP SCOUR
CLOUDS. AND THOSE CLOUDS ARE WIDESPREAD ON THE EARLY MORNING
11-3.9 MICRON CHANNEL. LAST NIGHTS RAOBS AND EARLY MORNING AMDAR
SOUNDINGS INDICATE THE MOISTURE TO BE SIGNIFICANTLY
DEEP...GENERALLY AROUND 15KFT. IN ADDITION...WITH THE BAGGY LOW-
LEVEL TROUGH DRAPED FROM WI THROUGH THE LOWER APPALACHIANS THIS
MORNING...THE WIND FLOW IS SOMEWHAT LIGHT AND CERTAINLY NOT
ALLOWING FOR ANY DRY AIR ADVECTION INTO THE AREA. MOST MODELS SEEM
TOO QUICK TO BREAK UP A LOT OF THE CLOUDS IN THEIR HUMIDITY
SOLUTIONS...BUT THEY DO AGREE ON A LIGHT WIND FIELD BY AFTERNOON
AND EVENING...NOT SUPPORTIVE OF DISSIPATION OF SUCH A DEEP CLOUD
LAYER. SO FAVOR THE SLOWER NAM SCOURING AND HAVE INCREASED THE
DURATION OF THE CLOUDS BY QUITE A WHILE...EXTENDING THEM INTO
TONIGHT FOR MOST PLACES. SOUTHWEST WINDS BEGIN TO KICK IN ALOFT
TOWARD DAYBREAK THU AND INCREASE THEREAFTER...WHICH SHOULD ALLOW
FOR THE LINGERING CLOUDS TO SCATTER AND ADVECT OFF TO THE
NORTHEAST THROUGHOUT THURSDAY MORNING.
ANY PRECIPITATION FOR TODAY SHOULD MAINLY BE CONFINED TO THIS
MORNING. CONTINUED GENTLE ISENTROPIC ASCENT ON THE 280K LAYER IS
ANALYZED BY THE RAP MODEL EXACTLY WHERE RADAR DEPICTS DRIZZLE AND
LIGHT RAIN ACROSS NE IL AND NW IN EARLY THIS MORNING. THIS SUPPORT
FADES SLOWLY THROUGH THE MORNING...AND NOT REALLY UNTIL LATE
MORNING AT THAT. MULTIPLE SHORT TERM MODELS SUPPORT THIS DOWNWARD
TREND ON REFLECTIVITY. SO HAVE SOME MENTION FOR DRIZZLE WITH
POCKETS OF LIGHT RAIN.
TEMPERATURES TODAY SHOULD STRUGGLE TO CLIMB MUCH. THE CLOUDS WITH
THE LOW ANGLE SUN AT THIS TIME OF YEAR SHOULD ALLOW FOR A DIURNAL
SPREAD FAR LOWER THAN THE NORMAL 16-18 DEGREES THIS TIME OF YEAR.
THIS MORNING ALONE PLACES MAY ONLY CLIMB A COUPLE DEGREES AT MOST.
THE TEMPERATURES TONIGHT ARE A BIG CHALLENGE AND DEPENDING ON
CLOUD COVER COULD VARY UP TO 15 DEGREES OR SO. HAVE TRENDED
WARMER FOR AREAS WHERE WE THINK CLOUDS WILL HANG ON THE LONGEST.
FAR WESTERN AND SOUTHERN AREAS SEEM THE MOST PROBABLE TO
POTENTIALLY CLEAR. WITH RAIN FROM LAST NIGHT AND THEN A COOL HIGH
TEMPERATURE TODAY...SUCH CLEARING WOULD VERY LIKELY FAVOR FOG AND
EVEN DENSE FOG AT THAT. HAVE ADDED THE DENSE POSSIBILITY ONTO THE
GOING FOG WORDING FOR TONIGHT.
WARM AIR ADVECTION THEN ENSUES THURSDAY INTO THE WEEKEND AS THE
CURRENT UPPER LOW OVER THE GULF OF ALASKA BEGINS TO FURTHER A
LONG WAVE TROUGH ACROSS WESTERN NORTH AMERICA. EACH DAY
PROGRESSIVELY WARMS ACROSS THE FORECAST AREA THROUGH
SATURDAY...AND POTENTIALLY EVEN INTO SUNDAY. THE LEAD PUSH OF
ELEVATED MOISTURE AND MORE STOUT WARM AIR ADVECTION ARRIVES FRIDAY
NIGHT INTO EARLY SATURDAY ON A LEAD SHORT WAVE. THICKNESS
DIFLUENCE AND SURPRISINGLY ELEVATED INSTABILITY ARE REASONABLE
WITH THIS FOR SOME SHOWERS AND EVEN THUNDER...BUT FORECAST DEEP
MOISTURE IS LACKING. THE GOING PLACEMENT OF LOW CHANCE POPS FOR
FRIDAY NIGHT INTO SATURDAY SEEMS VERY GOOD TO CAPTURE THESE
POSSIBILITIES...AND HAVE IN GENERAL MADE FEW CHANGES THERE.
TEMPERATURES ON SATURDAY LOOK TO BE QUITE MILD WITH THE ONLY FLY
IN THE OINTMENT SEEMINGLY IF CLOUDS EARLY HOLD THINGS BACK. BREEZY
SOUTHERLY WINDS WILL ENSUE AS SURFACE CYCLOGENESIS OCCURS FROM THE
CENTRAL PLAINS NORTHEASTWARD. THE 850 MB TEMPS FORECAST BY A
07.00Z EC/GFS BLEND ARE +14C. GIVEN JUST 850MB TEMPS IN EXCESS OF
10C THIS TIME OF YEAR...LOCAL RESEARCH CLIMATOLOGY FOR CHICAGO
SUPPORTS A MEDIAN HIGH OF 67 WITH 70 BEING THE UPPER 25TH
PERCENTILE. SO THE 70 DEGREE MARK IS NOT OUT OF THE QUESTION
ESPECIALLY IF WE START THE DAY SUNNY. SUNDAY IS A BIT MORE
CHALLENGING BUT WILL HAVE AN EVEN WARM STARTING POINT...LIKELY
AROUND 50 DEGREES. SO A FORECAST OF AT LEAST LOWER TO MID 60S
AREA WIDE ON BOTH WEEKEND DAYS HAS PRETTY HIGH CONFIDENCE
ESPECIALLY FOR THIS MANY DAYS OUT THIS TIME OF YEAR.
THE PRECIP CHANCES APPEAR BEST ALONG THE COLD FRONT SUNDAY
AFTERNOON AND NIGHT...WITH THAT FRONTAL TIMING BEING IN GOOD
AGREEMENT ON THE LONG RANGE GUIDANCE. STILL...CANNOT RULE OUT
EARLIER ACTIVITY AS MENTIONED ABOVE AS EARLY AS FRIDAY NIGHT...BUT
EVEN ON SATURDAY NIGHT THE LOW-LEVEL JET WILL BE STRONG ACROSS THE
AREA. HAVE CONTINUED TO INCREASE THE RAIN LIKELIHOOD ON SUNDAY AND
SUNDAY NIGHT...WITH CATEGORICAL POPS NOW IN THE FORECAST. SOME
THUNDER CERTAINLY REMAINS PLAUSIBLE WITH SUCH A DYNAMIC
PROJECTION. COLDER AND THEN DRIER AIR LOOKS TO WRAP IN ON
MONDAY...AND IT WILL BE A BIT OF A RACE TO SEE IF THAT COLDER AIR
WILL CATCH UP TO THE FORCING TO PROVIDE SOME SNOW ON THE BACK
SIDE. AT THIS TIME...THE FORECAST DOES CALL FOR FALLING
TEMPERATURES ON MONDAY WITH NORTHWEST WINDS INCREASING.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* AREAS MVFR CIGS EARLY AFTERNOON.
* MVFR VSBYS LATE EVENING AND OVERNIGHT.
* SOME POTENTIAL FOR LIFR CIGS AND OR VSBYS LATE NIGHT INTO THU
MORNING.
TRS
//DISCUSSION...UPDATED 18Z...
UPPER LOW THAT WAS OVER NORTHWEST IL LATE LAST NIGHT HAS
QUICKLY MOVED SOUTH-SOUTHEAST TO WESTERN TN AT MIDDAY TAKING
THE ASSOCIATED MID AND LOWER LEVEL CIRCULATIONS WITH IT...AS
WELL AS THE LIGHT RAIN AND DRIZZLE.
A WEAK SURFACE TROUGH EXTENDING FROM A WEAK SURFACE LOW IN
EASTERN TN NORTHWESTWARD ACROSS NORTHWESTERN IN AND FAR
NORTHEASTERN IL...AND NORTHWARD OVER EASTERN WI. THE WEAK WEAK
PRESSURE FIELD ACROSS THE REGION HAS AND CONTINUES TO RESULT IN
LIGHT WINDS...FAVORING A GENERALLY EAST-NORTHEAST TO NORTHEAST
LOW LEVEL FLOW EAST OF THE TROUGH AXIS...AND A NORTH TO NORTH-
NORTHWEST FLOW TO THE WEST. LOCAL WINDS TO BECOME EVEN LIGHTER
OR NIL TONIGHT AS A WEAK RIDGE OF HIGH PRESSURE OVER MN...
NORTHWESTERN IA...SOUTHEASTERN NE AND ON TO EAST TX MOVES E
ACROSS TO THE CENTRAL GREAT LAKES...LOWER OH VALLEY...AND LOWER
MS VALLEY BY 08.12Z. AFTER SUNRISE THU SOUTH-SOUTHWEST TO
SOUTHWEST WINDS WILL SET IN OVER THE LOCAL AREA ON THE WEST SIDE
OF THE RIDGE AXIS.
LOWER SURFACE DEW POINTS OVER LOWER MI AND NORTHEASTERN IN HAVE
BEEN ADVECTING WESTWARD TOWARD THE LOCAL AREA THOUGH ONLY VERY
SLOWLY GIVEN THE LIGHT LOW LEVEL WINDS. NONE THEN LESS...CLEARING
OF STRATUS AND STRATOCUMULUS HAS MADE IT AS FAR AS THE SOUTHERN
TIP OF LAKE MI AND PORTIONS OF NORTHWEST IN WITH FURTHER CLEARING
SLOWLY WORKING INTO FAR NORTHEAST IL LATE AFTERNOON/EARLY EVENING.
CLEARING ALSO EXPECTED TO MOVE IN FROM THE SOUTHWEST AS THE SOUTH-
SOUTHWEST TO SOUTHWEST LOW LEVEL FLOW GETS ESTABLISHED OVERNIGHT
AS THE RIDGE PASSES OVERHEAD.
WITH MOIST GROUND FOR EARLIER RAIN AND DRIZZLE AND LITTLE TO NO
SUNSHINE TO DRY THE SURFACE...POTENTIAL FOR AREAS OF DENSE FOG TO
DEVELOP TONIGHT AS CLEAR/CLEARING SKY...LIGHT TO NIL WINDS AND
MOIST SURFACE AND BOUNDARY LAYER TRAPPED UNDER SHALLOW SURFACE
BASED INVERSION WILL BE PRESENT. A COUPLE COMPLICATING FACTORS IN
DETERMINING OF DENSE FOG WILL FORM IS HOW QUICKLY THE SURFACE AND
LOW LEVEL FLOW ON THE BACK SIDE OF THE HIGH PRESSURE RIDGE
ESTABLISHES ITSELF...AND HOW QUICKLY CIRRUS CLOUDS SPILLING OVER
AND UPPER RIDGE TO THE WEST SPREAD OVER THE LOCAL AREA.
IF SOME FLOW AND THUS MIXING OCCURS IN THE BOUNDARY LAYER
OVERNIGHT THEN A LOW STRATUS DECK WOULD BE FAVORED OVER
AREAS/WIDESPREAD DENSE FOG...WHILE ARRIVAL OF CIRRUS OVER THE
LOCAL AREA DURING THE NIGHT WOULD LIMIT RADIATIONAL COOLING OF
THE SURFACE AND THE STRENGTH OF THE SURFACE BASED INVERSION
AND DISCOURAGE DENSE FOG. MODELS SUGGEST THAT BOTH A WEAK RETURN
LOW LEVEL FLOW AND AN INCREASE IN HIGH LEVEL CLOUDS WILL OCCUR
OVERNIGHT SO HAVE OPTED TO CONTINUE WITH THE IDEA OF NO DENSE FOG
OR LOW STRATUS DEVELOPMENT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN REMAINING VFR THIS AFTERNOON INTO EARLY
EVENING.
* HIGH CONFIDENCE IN WINDS REMAINING AT OR BELOW 6 KT THIS
AFTERNOON AND TONIGHT.
* MODERATE CONFIDENCE IN SKY CONDITION/CEILING AND VISIBILITY
FORECASTS FOR LATE NIGHT THROUGH SUNRISE THU.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...SLIGHT CHANCE SHRA LATE.
SATURDAY...CHANCE RA.
SUNDAY...LIKELY SHRA WITH CHC TSRA. MVFR/IFR POSSIBLE.
MONDAY...CHC RAIN CHANGING TO SNOW. MVFR/IFR POSSIBLE.
TUESDAY...VFR.
KREIN
&&
.MARINE...
300 AM CST
A WEAK TROUGH OF LOW PRESSURE OVER ILLINOIS THROUGH THE WESTERN
GREAT LAKES COMBINED WITH HIGH PRESSURE OVER SOUTHEASTERN CANADA
HAS GENERATED 10 TO 20 KT SOUTHEAST WINDS. WINDS WILL WEAKEN
TONIGHT AS A RIDGE OF HIGH PRESSURE OF BUILDS EASTWARD TO THE
WESTERN GREAT LAKES. MEANWHILE...LOW PRESSURE IS FORECAST TO
DEVELOP OVER THE CENTRAL PLAINS FRIDAY NIGHT AND TRACK NORTHEAST
TO WESTERN LAKE SUPERIOR BY SUNDAY MORNING. A SOUTHERLY PRESSURE
GRADIENT WILL STRENGTHEN OVER THE LAKE AS THE LOW TRACKS
NORTHEASTWARD...WITH SOUTH WINDS INCREASING TO 15 TO 25 KT FOR
THURSDAY AND FRIDAY. WINDS SHOULD STRENGTHEN AT LEAST 30KT FOR
SATURDAY THROUGH EARLY SUNDAY AS THE LOW INTENSIFIES SOME WHILE
TRACKING
THROUGH THE UPPER MISSISSIPPI VALLEY. THERE IS A CHANCE FOR SOUTH
GALES DURING THIS PERIOD. BY LATE SUNDAY...THE LOW WILL TRACK TO
JAMES BAY WHILE DRAGGING A STRONG COLD FRONT ACROSS THE
LAKE...BRINGING A QUICK SHIFT TO NORTHWESTERLY WINDS AND A RAPID
INFLUX OF MUCH COLDER AIR.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1013 AM CST WED NOV 7 2012
.DISCUSSION UPDATE...
1115 AM CST
NOT MUCH CHANGE IN FORECAST. LIGHT RAIN AND DRIZZLE HAS ENDED AS
SHORT WAVE CONTINUES TO MOVE SOUTHEAST AWAY FROM THE AREA. WITH WEAK
PRESSURE PATTERN AND LIGHT WINDS...DON`T SEE MUCH PROSPECT OF ANY
CLEARING. SOME DRIER AIR NOTED OVER MI AND IN BUT ADVECTION IS VERY
WEAK. SOME PARTIAL SUN OVER NORTHWEST IN AND FAR EASTERN IL
POSSIBLE. CLEARING WILL BE SLOW TONIGHT AND ANYPLACE THAT CLEARS
WILL LIKELY FOG IN LATER TONIGHT AND THURSDAY MORNING. WITH OVERCAST
CONDITIONS TEMPERATURES WON`T MOVE MUCH THE REST OF TODAY.
ALLSOPP/CASTRO
PREVIOUS DISCUSSION...
322 AM CST
THE IMMEDIATE FORECAST CHALLENGES ARE LINGERING DRIZZLE/LIGHT
RAIN AND ALSO CLOUDS...WITH THE LATTER REMAINING POTENTIALLY INTO
THURSDAY. THEN ATTENTION TURNS TO WHAT DEGREE OF WARM-UP WILL BE
REALIZED AS THE PATTERN BECOMES MORE AMPLIFIED...PROVIDING THE
FINAL CHALLENGE OF PRECIP CHANCES THIS WEEKEND INTO EARLY NEXT
WEEK.
A BROAD UPPER TROUGH WITH DISTINCT POTENT SHORT WAVES HAS EVOLVED
OVER THE EASTERN U.S. FROM LATE YESTERDAY AFTERNOON INTO THIS
MORNING. FINAL SHORT WAVE IS PROGRESSING SOUTHEASTWARD ACROSS
CENTRAL IL EARLY THIS MORNING. STRONG 120+ KNOT NORTH-TO-SOUTH JET
IS LINED UP OVER THE MISSISSIPPI RIVER VALLEY AND WILL HELP TO
PROGRESS THIS SOUTH. THE AREA WILL REMAIN ON THE CYCLONIC SIDE OF
THIS STRONG JET THROUGH TODAY...AND ASSOCIATED MID-LEVEL SHEAR
VORTICITY WILL NOT OFFER MUCH FOR SUPPRESSION TO HELP SCOUR
CLOUDS. AND THOSE CLOUDS ARE WIDESPREAD ON THE EARLY MORNING
11-3.9 MICRON CHANNEL. LAST NIGHTS RAOBS AND EARLY MORNING AMDAR
SOUNDINGS INDICATE THE MOISTURE TO BE SIGNIFICANTLY
DEEP...GENERALLY AROUND 15KFT. IN ADDITION...WITH THE BAGGY LOW-
LEVEL TROUGH DRAPED FROM WI THROUGH THE LOWER APPALACHIANS THIS
MORNING...THE WIND FLOW IS SOMEWHAT LIGHT AND CERTAINLY NOT
ALLOWING FOR ANY DRY AIR ADVECTION INTO THE AREA. MOST MODELS SEEM
TOO QUICK TO BREAK UP A LOT OF THE CLOUDS IN THEIR HUMIDITY
SOLUTIONS...BUT THEY DO AGREE ON A LIGHT WIND FIELD BY AFTERNOON
AND EVENING...NOT SUPPORTIVE OF DISSIPATION OF SUCH A DEEP CLOUD
LAYER. SO FAVOR THE SLOWER NAM SCOURING AND HAVE INCREASED THE
DURATION OF THE CLOUDS BY QUITE A WHILE...EXTENDING THEM INTO
TONIGHT FOR MOST PLACES. SOUTHWEST WINDS BEGIN TO KICK IN ALOFT
TOWARD DAYBREAK THU AND INCREASE THEREAFTER...WHICH SHOULD ALLOW
FOR THE LINGERING CLOUDS TO SCATTER AND ADVECT OFF TO THE
NORTHEAST THROUGHOUT THURSDAY MORNING.
ANY PRECIPITATION FOR TODAY SHOULD MAINLY BE CONFINED TO THIS
MORNING. CONTINUED GENTLE ISENTROPIC ASCENT ON THE 280K LAYER IS
ANALYZED BY THE RAP MODEL EXACTLY WHERE RADAR DEPICTS DRIZZLE AND
LIGHT RAIN ACROSS NE IL AND NW IN EARLY THIS MORNING. THIS SUPPORT
FADES SLOWLY THROUGH THE MORNING...AND NOT REALLY UNTIL LATE
MORNING AT THAT. MULTIPLE SHORT TERM MODELS SUPPORT THIS DOWNWARD
TREND ON REFLECTIVITY. SO HAVE SOME MENTION FOR DRIZZLE WITH
POCKETS OF LIGHT RAIN.
TEMPERATURES TODAY SHOULD STRUGGLE TO CLIMB MUCH. THE CLOUDS WITH
THE LOW ANGLE SUN AT THIS TIME OF YEAR SHOULD ALLOW FOR A DIURNAL
SPREAD FAR LOWER THAN THE NORMAL 16-18 DEGREES THIS TIME OF YEAR.
THIS MORNING ALONE PLACES MAY ONLY CLIMB A COUPLE DEGREES AT MOST.
THE TEMPERATURES TONIGHT ARE A BIG CHALLENGE AND DEPENDING ON
CLOUD COVER COULD VARY UP TO 15 DEGREES OR SO. HAVE TRENDED
WARMER FOR AREAS WHERE WE THINK CLOUDS WILL HANG ON THE LONGEST.
FAR WESTERN AND SOUTHERN AREAS SEEM THE MOST PROBABLE TO
POTENTIALLY CLEAR. WITH RAIN FROM LAST NIGHT AND THEN A COOL HIGH
TEMPERATURE TODAY...SUCH CLEARING WOULD VERY LIKELY FAVOR FOG AND
EVEN DENSE FOG AT THAT. HAVE ADDED THE DENSE POSSIBILITY ONTO THE
GOING FOG WORDING FOR TONIGHT.
WARM AIR ADVECTION THEN ENSUES THURSDAY INTO THE WEEKEND AS THE
CURRENT UPPER LOW OVER THE GULF OF ALASKA BEGINS TO FURTHER A
LONG WAVE TROUGH ACROSS WESTERN NORTH AMERICA. EACH DAY
PROGRESSIVELY WARMS ACROSS THE FORECAST AREA THROUGH
SATURDAY...AND POTENTIALLY EVEN INTO SUNDAY. THE LEAD PUSH OF
ELEVATED MOISTURE AND MORE STOUT WARM AIR ADVECTION ARRIVES FRIDAY
NIGHT INTO EARLY SATURDAY ON A LEAD SHORT WAVE. THICKNESS
DIFLUENCE AND SURPRISINGLY ELEVATED INSTABILITY ARE REASONABLE
WITH THIS FOR SOME SHOWERS AND EVEN THUNDER...BUT FORECAST DEEP
MOISTURE IS LACKING. THE GOING PLACEMENT OF LOW CHANCE POPS FOR
FRIDAY NIGHT INTO SATURDAY SEEMS VERY GOOD TO CAPTURE THESE
POSSIBILITIES...AND HAVE IN GENERAL MADE FEW CHANGES THERE.
TEMPERATURES ON SATURDAY LOOK TO BE QUITE MILD WITH THE ONLY FLY
IN THE OINTMENT SEEMINGLY IF CLOUDS EARLY HOLD THINGS BACK. BREEZY
SOUTHERLY WINDS WILL ENSUE AS SURFACE CYCLOGENESIS OCCURS FROM THE
CENTRAL PLAINS NORTHEASTWARD. THE 850 MB TEMPS FORECAST BY A
07.00Z EC/GFS BLEND ARE +14C. GIVEN JUST 850MB TEMPS IN EXCESS OF
10C THIS TIME OF YEAR...LOCAL RESEARCH CLIMATOLOGY FOR CHICAGO
SUPPORTS A MEDIAN HIGH OF 67 WITH 70 BEING THE UPPER 25TH
PERCENTILE. SO THE 70 DEGREE MARK IS NOT OUT OF THE QUESTION
ESPECIALLY IF WE START THE DAY SUNNY. SUNDAY IS A BIT MORE
CHALLENGING BUT WILL HAVE AN EVEN WARM STARTING POINT...LIKELY
AROUND 50 DEGREES. SO A FORECAST OF AT LEAST LOWER TO MID 60S
AREA WIDE ON BOTH WEEKEND DAYS HAS PRETTY HIGH CONFIDENCE
ESPECIALLY FOR THIS MANY DAYS OUT THIS TIME OF YEAR.
THE PRECIP CHANCES APPEAR BEST ALONG THE COLD FRONT SUNDAY
AFTERNOON AND NIGHT...WITH THAT FRONTAL TIMING BEING IN GOOD
AGREEMENT ON THE LONG RANGE GUIDANCE. STILL...CANNOT RULE OUT
EARLIER ACTIVITY AS MENTIONED ABOVE AS EARLY AS FRIDAY NIGHT...BUT
EVEN ON SATURDAY NIGHT THE LOW-LEVEL JET WILL BE STRONG ACROSS THE
AREA. HAVE CONTINUED TO INCREASE THE RAIN LIKELIHOOD ON SUNDAY AND
SUNDAY NIGHT...WITH CATEGORICAL POPS NOW IN THE FORECAST. SOME
THUNDER CERTAINLY REMAINS PLAUSIBLE WITH SUCH A DYNAMIC
PROJECTION. COLDER AND THEN DRIER AIR LOOKS TO WRAP IN ON
MONDAY...AND IT WILL BE A BIT OF A RACE TO SEE IF THAT COLDER AIR
WILL CATCH UP TO THE FORCING TO PROVIDE SOME SNOW ON THE BACK
SIDE. AT THIS TIME...THE FORECAST DOES CALL FOR FALLING
TEMPERATURES ON MONDAY WITH NORTHWEST WINDS INCREASING.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* MVFR VSBY PREVAILING REST OF MORNING.
* PREVAILING MVFR CIGS IMPROVING TO VFR THIS AFTERNOON.
* MVFR VIS WITH BR TONIGHT...POSSIBLE IFR/LIFR IN FG OVERNIGHT
INTO EARLY THU MORNING.
TRS
//DISCUSSION...UPDATED 14Z...
MOST OF WEAK RADAR ECHOES HAVE DISSIPATED IN THE PAST 2 HRS. THIS
CORRESPONDING WELL WITH ISENTROPIC SFCS INDICATING TOTAL LOSS OF
MID LVL UPGLIDE OVER THE LOCAL AREA 12-15Z...WITH IR SATELLITE
ALSO SHOWING LOSS OF MID LVL CLOUDS AND WITH LLVL UPGLIDE BECOMING
MINIMAL AT BEST BY 16Z PER LATEST RUC MODEL RUN. DO NOT WANT TO
RUSH IMPROVEMENT IN CIGS AS WE TEND TO DO SOMETIMES BUT APPEARS
THAT WITH SLIGHTLY DRIER LLVL AIR ADVECTING IN AS INVERTED SFC
TROF DRIFTS A BIT FURTHER TO THE W THAT SHUD STA PREVAILING MVFR
CIGS ACROSS CHI AREA THRU AFTERNOON.
TRS
PREVIOUS DISCUSSION...UPDATED 12Z...
WEAK...DIFFUSE TROUGH OF LOW PRESSURE SLOWLY SAGGING SWD THROUGH
ILLINOIS. LATEST RADAR IMAGERY SHOWS A PATCH OF LIGHT PCPN
WRAPPING AROUND THE LOW CENTER OVER NWRN IN/NERN IL...SO THERE IS
STILL A CHANCE FOR SOME -DZ/-RA AT THE TERMINALS FOR A FEW MORE
HOURS THIS MORNING. LATEST CIG TRENDS SHOW CIGS LIFTING TO
MVFR...BUT THERE WILL STILL BE A CHANCE FOR AT LEAST OCNL IFR THIS
MORNING UNTIL THE SFC LOW MOVES FARTHER SOUTH AND SOME DRIER AIR
CAN ADVECT IN FROM THE NORTH. OTHERWISE...MODEL RH TIME SECTIONS
INDICATE THAT MVFR CIGS SHOULD HOLD IN THROUGH MUCH OF THE DAY. BE
EARLY EVENING...HIGH PRESSURE SHOULD BEGIN TO OVERSPREAD THE
REGION...ALLOWING MUCH OF THE CLOUD COVER TO ERODE...BUT WITH SFC
WINDS REMAINING LIGHT THROUGH THE PERIOD...THERE WILL BE A CHANCE
FOR VIS TO DROP TO MVFR OR IFR OVERNIGHT TONIGHT WITH BR/FG
DEVELOPMENT LIKELY. EXACTLY HOW LOW VIS WILL DROP TONIGHT IS STILL
QUESTIONABLE AND WILL DEPEND ON HOW MUCH HIGH CLOUD COVER WILL BE
PRESENT.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM CONFIDENCE IN CIG/VIS TRENDS THROUGH AFTERNOON. AFTERNOON.
* LOW CONFIDENCE IN CONDITIONS REMAINING MVFR THROUGH OVERNIGHT
INTO EARLY MORNING.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...SLIGHT CHANCE SHRA LATE.
SATURDAY...CHANCE RA.
SUNDAY...LIKELY SHRA WITH CHC TSRA. MVFR/IFR POSSIBLE.
MONDAY...CHC RAIN CHANGING TO SNOW. MVFR/IFR POSSIBLE.
TUESDAY...VFR.
KREIN
&&
.MARINE...
300 AM CST
A WEAK TROUGH OF LOW PRESSURE OVER ILLINOIS THROUGH THE WESTERN
GREAT LAKES COMBINED WITH HIGH PRESSURE OVER SOUTHEASTERN CANADA
HAS GENERATED 10 TO 20 KT SOUTHEAST WINDS. WINDS WILL WEAKEN
TONIGHT AS A RIDGE OF HIGH PRESSURE OF BUILDS EASTWARD TO THE
WESTERN GREAT LAKES. MEANWHILE...LOW PRESSURE IS FORECAST TO
DEVELOP OVER THE CENTRAL PLAINS FRIDAY NIGHT AND TRACK NORTHEAST
TO WESTERN LAKE SUPERIOR BY SUNDAY MORNING. A SOUTHERLY PRESSURE
GRADIENT WILL STRENGTHEN OVER THE LAKE AS THE LOW TRACKS
NORTHEASTWARD...WITH SOUTH WINDS INCREASING TO 15 TO 25 KT FOR
THURSDAY AND FRIDAY. WINDS SHOULD STRENGTHEN AT LEAST 30KT FOR
SATURDAY THROUGH EARLY SUNDAY AS THE LOW INTENSIFIES SOME WHILE
TRACKING
THROUGH THE UPPER MISSISSIPPI VALLEY. THERE IS A CHANCE FOR SOUTH
GALES DURING THIS PERIOD. BY LATE SUNDAY...THE LOW WILL TRACK TO
JAMES BAY WHILE DRAGGING A STRONG COLD FRONT ACROSS THE
LAKE...BRINGING A QUICK SHIFT TO NORTHWESTERLY WINDS AND A RAPID
INFLUX OF MUCH COLDER AIR.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
854 AM CST WED NOV 7 2012
.DISCUSSION...
322 AM CST
THE IMMEDIATE FORECAST CHALLENGES ARE LINGERING DRIZZLE/LIGHT
RAIN AND ALSO CLOUDS...WITH THE LATTER REMAINING POTENTIALLY INTO
THURSDAY. THEN ATTENTION TURNS TO WHAT DEGREE OF WARM-UP WILL BE
REALIZED AS THE PATTERN BECOMES MORE AMPLIFIED...PROVIDING THE
FINAL CHALLENGE OF PRECIP CHANCES THIS WEEKEND INTO EARLY NEXT
WEEK.
A BROAD UPPER TROUGH WITH DISTINCT POTENT SHORT WAVES HAS EVOLVED
OVER THE EASTERN U.S. FROM LATE YESTERDAY AFTERNOON INTO THIS
MORNING. FINAL SHORT WAVE IS PROGRESSING SOUTHEASTWARD ACROSS
CENTRAL IL EARLY THIS MORNING. STRONG 120+ KNOT NORTH-TO-SOUTH JET
IS LINED UP OVER THE MISSISSIPPI RIVER VALLEY AND WILL HELP TO
PROGRESS THIS SOUTH. THE AREA WILL REMAIN ON THE CYCLONIC SIDE OF
THIS STRONG JET THROUGH TODAY...AND ASSOCIATED MID-LEVEL SHEAR
VORTICITY WILL NOT OFFER MUCH FOR SUPPRESSION TO HELP SCOUR
CLOUDS. AND THOSE CLOUDS ARE WIDESPREAD ON THE EARLY MORNING
11-3.9 MICRON CHANNEL. LAST NIGHTS RAOBS AND EARLY MORNING AMDAR
SOUNDINGS INDICATE THE MOISTURE TO BE SIGNIFICANTLY
DEEP...GENERALLY AROUND 15KFT. IN ADDITION...WITH THE BAGGY LOW-
LEVEL TROUGH DRAPED FROM WI THROUGH THE LOWER APPALACHIANS THIS
MORNING...THE WIND FLOW IS SOMEWHAT LIGHT AND CERTAINLY NOT
ALLOWING FOR ANY DRY AIR ADVECTION INTO THE AREA. MOST MODELS SEEM
TOO QUICK TO BREAK UP A LOT OF THE CLOUDS IN THEIR HUMIDITY
SOLUTIONS...BUT THEY DO AGREE ON A LIGHT WIND FIELD BY AFTERNOON
AND EVENING...NOT SUPPORTIVE OF DISSIPATION OF SUCH A DEEP CLOUD
LAYER. SO FAVOR THE SLOWER NAM SCOURING AND HAVE INCREASED THE
DURATION OF THE CLOUDS BY QUITE A WHILE...EXTENDING THEM INTO
TONIGHT FOR MOST PLACES. SOUTHWEST WINDS BEGIN TO KICK IN ALOFT
TOWARD DAYBREAK THU AND INCREASE THEREAFTER...WHICH SHOULD ALLOW
FOR THE LINGERING CLOUDS TO SCATTER AND ADVECT OFF TO THE
NORTHEAST THROUGHOUT THURSDAY MORNING.
ANY PRECIPITATION FOR TODAY SHOULD MAINLY BE CONFINED TO THIS
MORNING. CONTINUED GENTLE ISENTROPIC ASCENT ON THE 280K LAYER IS
ANALYZED BY THE RAP MODEL EXACTLY WHERE RADAR DEPICTS DRIZZLE AND
LIGHT RAIN ACROSS NE IL AND NW IN EARLY THIS MORNING. THIS SUPPORT
FADES SLOWLY THROUGH THE MORNING...AND NOT REALLY UNTIL LATE
MORNING AT THAT. MULTIPLE SHORT TERM MODELS SUPPORT THIS DOWNWARD
TREND ON REFLECTIVITY. SO HAVE SOME MENTION FOR DRIZZLE WITH
POCKETS OF LIGHT RAIN.
TEMPERATURES TODAY SHOULD STRUGGLE TO CLIMB MUCH. THE CLOUDS WITH
THE LOW ANGLE SUN AT THIS TIME OF YEAR SHOULD ALLOW FOR A DIURNAL
SPREAD FAR LOWER THAN THE NORMAL 16-18 DEGREES THIS TIME OF YEAR.
THIS MORNING ALONE PLACES MAY ONLY CLIMB A COUPLE DEGREES AT MOST.
THE TEMPERATURES TONIGHT ARE A BIG CHALLENGE AND DEPENDING ON
CLOUD COVER COULD VARY UP TO 15 DEGREES OR SO. HAVE TRENDED
WARMER FOR AREAS WHERE WE THINK CLOUDS WILL HANG ON THE LONGEST.
FAR WESTERN AND SOUTHERN AREAS SEEM THE MOST PROBABLE TO
POTENTIALLY CLEAR. WITH RAIN FROM LAST NIGHT AND THEN A COOL HIGH
TEMPERATURE TODAY...SUCH CLEARING WOULD VERY LIKELY FAVOR FOG AND
EVEN DENSE FOG AT THAT. HAVE ADDED THE DENSE POSSIBILITY ONTO THE
GOING FOG WORDING FOR TONIGHT.
WARM AIR ADVECTION THEN ENSUES THURSDAY INTO THE WEEKEND AS THE
CURRENT UPPER LOW OVER THE GULF OF ALASKA BEGINS TO FURTHER A
LONG WAVE TROUGH ACROSS WESTERN NORTH AMERICA. EACH DAY
PROGRESSIVELY WARMS ACROSS THE FORECAST AREA THROUGH
SATURDAY...AND POTENTIALLY EVEN INTO SUNDAY. THE LEAD PUSH OF
ELEVATED MOISTURE AND MORE STOUT WARM AIR ADVECTION ARRIVES FRIDAY
NIGHT INTO EARLY SATURDAY ON A LEAD SHORT WAVE. THICKNESS
DIFLUENCE AND SURPRISINGLY ELEVATED INSTABILITY ARE REASONABLE
WITH THIS FOR SOME SHOWERS AND EVEN THUNDER...BUT FORECAST DEEP
MOISTURE IS LACKING. THE GOING PLACEMENT OF LOW CHANCE POPS FOR
FRIDAY NIGHT INTO SATURDAY SEEMS VERY GOOD TO CAPTURE THESE
POSSIBILITIES...AND HAVE IN GENERAL MADE FEW CHANGES THERE.
TEMPERATURES ON SATURDAY LOOK TO BE QUITE MILD WITH THE ONLY FLY
IN THE OINTMENT SEEMINGLY IF CLOUDS EARLY HOLD THINGS BACK. BREEZY
SOUTHERLY WINDS WILL ENSUE AS SURFACE CYCLOGENESIS OCCURS FROM THE
CENTRAL PLAINS NORTHEASTWARD. THE 850 MB TEMPS FORECAST BY A
07.00Z EC/GFS BLEND ARE +14C. GIVEN JUST 850MB TEMPS IN EXCESS OF
10C THIS TIME OF YEAR...LOCAL RESEARCH CLIMATOLOGY FOR CHICAGO
SUPPORTS A MEDIAN HIGH OF 67 WITH 70 BEING THE UPPER 25TH
PERCENTILE. SO THE 70 DEGREE MARK IS NOT OUT OF THE QUESTION
ESPECIALLY IF WE START THE DAY SUNNY. SUNDAY IS A BIT MORE
CHALLENGING BUT WILL HAVE AN EVEN WARM STARTING POINT...LIKELY
AROUND 50 DEGREES. SO A FORECAST OF AT LEAST LOWER TO MID 60S
AREA WIDE ON BOTH WEEKEND DAYS HAS PRETTY HIGH CONFIDENCE
ESPECIALLY FOR THIS MANY DAYS OUT THIS TIME OF YEAR.
THE PRECIP CHANCES APPEAR BEST ALONG THE COLD FRONT SUNDAY
AFTERNOON AND NIGHT...WITH THAT FRONTAL TIMING BEING IN GOOD
AGREEMENT ON THE LONG RANGE GUIDANCE. STILL...CANNOT RULE OUT
EARLIER ACTIVITY AS MENTIONED ABOVE AS EARLY AS FRIDAY NIGHT...BUT
EVEN ON SATURDAY NIGHT THE LOW-LEVEL JET WILL BE STRONG ACROSS THE
AREA. HAVE CONTINUED TO INCREASE THE RAIN LIKELIHOOD ON SUNDAY AND
SUNDAY NIGHT...WITH CATEGORICAL POPS NOW IN THE FORECAST. SOME
THUNDER CERTAINLY REMAINS PLAUSIBLE WITH SUCH A DYNAMIC
PROJECTION. COLDER AND THEN DRIER AIR LOOKS TO WRAP IN ON
MONDAY...AND IT WILL BE A BIT OF A RACE TO SEE IF THAT COLDER AIR
WILL CATCH UP TO THE FORCING TO PROVIDE SOME SNOW ON THE BACK
SIDE. AT THIS TIME...THE FORECAST DOES CALL FOR FALLING
TEMPERATURES ON MONDAY WITH NORTHWEST WINDS INCREASING.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* MVFR VSBYS TIL EARLY AFTERNOON.
* MVFR CIGS IMPROVING TO VFR LATE AFTERNOON/EARLY EVENING.
* POSSIBILITY OF ADDITIONAL -DZ.
* MVFR VIS WITH BR TONIGHT...POSSIBLE IFR/LIFR IN FG OVERNIGHT
INTO EARLY THU MORNING.
TRS
//DISCUSSION...UPDATED 14Z...
MOST OF WEAK RADAR ECHOES HAVE DISSIPATED IN THE PAST 2 HRS. THIS
CORRESPONDING WELL WITH ISENTROPIC SFCS INDICATING TOTAL LOSS OF
MID LVL UPGLIDE OVER THE LOCAL AREA 12-15Z...WITH IR SATELLITE
ALSO SHOWING LOSS OF MID LVL CLOUDS AND WITH LLVL UPGLIDE BECOMING
MINIMAL AT BEST BY 16Z PER LATEST RUC MODEL RUN. DO NOT WANT TO
RUSH IMPROVEMENT IN CIGS AS WE TEND TO DO SOMETIMES BUT APPEARS
THAT WITH SLIGHTLY DRIER LLVL AIR ADVECTING IN AS INVERTED SFC
TROF DRIFTS A BIT FURTHER TO THE W THAT SHUD STA PREVAILING MVFR
CIGS ACROSS CHI AREA THRU AFTERNOON.
TRS
PREVIOUS DISCUSSION...UPDATED 12Z...
WEAK...DIFFUSE TROUGH OF LOW PRESSURE SLOWLY SAGGING SWD THROUGH
ILLINOIS. LATEST RADAR IMAGERY SHOWS A PATCH OF LIGHT PCPN
WRAPPING AROUND THE LOW CENTER OVER NWRN IN/NERN IL...SO THERE IS
STILL A CHANCE FOR SOME -DZ/-RA AT THE TERMINALS FOR A FEW MORE
HOURS THIS MORNING. LATEST CIG TRENDS SHOW CIGS LIFTING TO
MVFR...BUT THERE WILL STILL BE A CHANCE FOR AT LEAST OCNL IFR THIS
MORNING UNTIL THE SFC LOW MOVES FARTHER SOUTH AND SOME DRIER AIR
CAN ADVECT IN FROM THE NORTH. OTHERWISE...MODEL RH TIME SECTIONS
INDICATE THAT MVFR CIGS SHOULD HOLD IN THROUGH MUCH OF THE DAY. BE
EARLY EVENING...HIGH PRESSURE SHOULD BEGIN TO OVERSPREAD THE
REGION...ALLOWING MUCH OF THE CLOUD COVER TO ERODE...BUT WITH SFC
WINDS REMAINING LIGHT THROUGH THE PERIOD...THERE WILL BE A CHANCE
FOR VIS TO DROP TO MVFR OR IFR OVERNIGHT TONIGHT WITH BR/FG
DEVELOPMENT LIKELY. EXACTLY HOW LOW VIS WILL DROP TONIGHT IS STILL
QUESTIONABLE AND WILL DEPEND ON HOW MUCH HIGH CLOUD COVER WILL BE
PRESENT.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM CONFIDENCE IN CIG/VIS TRENDS MID MORNING INTO AFTERNOON.
* HIGH CONFIDENCE IN NO ADDITIONAL SIG -RA/-DZ.
* LOW CONFIDENCE IN IFR/LIFR LATE TONIGHT THRU PCPN TRENDS THIS
MORNING.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...SLIGHT LATE.
SATURDAY...CHANCE RA .
SUNDAY...LIKELY SHRA WITH CHC TSRA. MVFR/IFR POSSIBLE.
MONDAY...CHC RAIN CHANGING TO SNOW. MVFR/IFR POSSIBLE.
TUESDAY...VFR.
KREIN
&&
.MARINE...
300 AM CST
A WEAK TROUGH OF LOW PRESSURE OVER ILLINOIS THROUGH THE WESTERN
GREAT LAKES COMBINED WITH HIGH PRESSURE OVER SOUTHEASTERN CANADA
HAS GENERATED 10 TO 20 KT SOUTHEAST WINDS. WINDS WILL WEAKEN
TONIGHT AS A RIDGE OF HIGH PRESSURE OF BUILDS EASTWARD TO THE
WESTERN GREAT LAKES. MEANWHILE...LOW PRESSURE IS FORECAST TO
DEVELOP OVER THE CENTRAL PLAINS FRIDAY NIGHT AND TRACK NORTHEAST
TO WESTERN LAKE SUPERIOR BY SUNDAY MORNING. A SOUTHERLY PRESSURE
GRADIENT WILL STRENGTHEN OVER THE LAKE AS THE LOW TRACKS
NORTHEASTWARD...WITH SOUTH WINDS INCREASING TO 15 TO 25 KT FOR
THURSDAY AND FRIDAY. WINDS SHOULD STRENGTHEN AT LEAST 30KT FOR
SATURDAY THROUGH EARLY SUNDAY AS THE LOW INTENSIFIES SOME WHILE TRACKING
THROUGH THE UPPER MISSISSIPPI VALLEY. THERE IS A CHANCE FOR SOUTH
GALES DURING THIS PERIOD. BY LATE SUNDAY...THE LOW WILL TRACK TO
JAMES BAY WHILE DRAGGING A STRONG COLD FRONT ACROSS THE
LAKE...BRINGING A QUICK SHIFT TO NORTHWESTERLY WINDS AND A RAPID
INFLUX OF MUCH COLDER AIR.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
549 AM CST WED NOV 7 2012
.DISCUSSION...
322 AM CST
THE IMMEDIATE FORECAST CHALLENGES ARE LINGERING DRIZZLE/LIGHT
RAIN AND ALSO CLOUDS...WITH THE LATTER REMAINING POTENTIALLY INTO
THURSDAY. THEN ATTENTION TURNS TO WHAT DEGREE OF WARM-UP WILL BE
REALIZED AS THE PATTERN BECOMES MORE AMPLIFIED...PROVIDING THE
FINAL CHALLENGE OF PRECIP CHANCES THIS WEEKEND INTO EARLY NEXT
WEEK.
A BROAD UPPER TROUGH WITH DISTINCT POTENT SHORT WAVES HAS EVOLVED
OVER THE EASTERN U.S. FROM LATE YESTERDAY AFTERNOON INTO THIS
MORNING. FINAL SHORT WAVE IS PROGRESSING SOUTHEASTWARD ACROSS
CENTRAL IL EARLY THIS MORNING. STRONG 120+ KNOT NORTH-TO-SOUTH JET
IS LINED UP OVER THE MISSISSIPPI RIVER VALLEY AND WILL HELP TO
PROGRESS THIS SOUTH. THE AREA WILL REMAIN ON THE CYCLONIC SIDE OF
THIS STRONG JET THROUGH TODAY...AND ASSOCIATED MID-LEVEL SHEAR
VORTICITY WILL NOT OFFER MUCH FOR SUPPRESSION TO HELP SCOUR
CLOUDS. AND THOSE CLOUDS ARE WIDESPREAD ON THE EARLY MORNING
11-3.9 MICRON CHANNEL. LAST NIGHTS RAOBS AND EARLY MORNING AMDAR
SOUNDINGS INDICATE THE MOISTURE TO BE SIGNIFICANTLY
DEEP...GENERALLY AROUND 15KFT. IN ADDITION...WITH THE BAGGY LOW-
LEVEL TROUGH DRAPED FROM WI THROUGH THE LOWER APPALACHIANS THIS
MORNING...THE WIND FLOW IS SOMEWHAT LIGHT AND CERTAINLY NOT
ALLOWING FOR ANY DRY AIR ADVECTION INTO THE AREA. MOST MODELS SEEM
TOO QUICK TO BREAK UP A LOT OF THE CLOUDS IN THEIR HUMIDITY
SOLUTIONS...BUT THEY DO AGREE ON A LIGHT WIND FIELD BY AFTERNOON
AND EVENING...NOT SUPPORTIVE OF DISSIPATION OF SUCH A DEEP CLOUD
LAYER. SO FAVOR THE SLOWER NAM SCOURING AND HAVE INCREASED THE
DURATION OF THE CLOUDS BY QUITE A WHILE...EXTENDING THEM INTO
TONIGHT FOR MOST PLACES. SOUTHWEST WINDS BEGIN TO KICK IN ALOFT
TOWARD DAYBREAK THU AND INCREASE THEREAFTER...WHICH SHOULD ALLOW
FOR THE LINGERING CLOUDS TO SCATTER AND ADVECT OFF TO THE
NORTHEAST THROUGHOUT THURSDAY MORNING.
ANY PRECIPITATION FOR TODAY SHOULD MAINLY BE CONFINED TO THIS
MORNING. CONTINUED GENTLE ISENTROPIC ASCENT ON THE 280K LAYER IS
ANALYZED BY THE RAP MODEL EXACTLY WHERE RADAR DEPICTS DRIZZLE AND
LIGHT RAIN ACROSS NE IL AND NW IN EARLY THIS MORNING. THIS SUPPORT
FADES SLOWLY THROUGH THE MORNING...AND NOT REALLY UNTIL LATE
MORNING AT THAT. MULTIPLE SHORT TERM MODELS SUPPORT THIS DOWNWARD
TREND ON REFLECTIVITY. SO HAVE SOME MENTION FOR DRIZZLE WITH
POCKETS OF LIGHT RAIN.
TEMPERATURES TODAY SHOULD STRUGGLE TO CLIMB MUCH. THE CLOUDS WITH
THE LOW ANGLE SUN AT THIS TIME OF YEAR SHOULD ALLOW FOR A DIURNAL
SPREAD FAR LOWER THAN THE NORMAL 16-18 DEGREES THIS TIME OF YEAR.
THIS MORNING ALONE PLACES MAY ONLY CLIMB A COUPLE DEGREES AT MOST.
THE TEMPERATURES TONIGHT ARE A BIG CHALLENGE AND DEPENDING ON
CLOUD COVER COULD VARY UP TO 15 DEGREES OR SO. HAVE TRENDED
WARMER FOR AREAS WHERE WE THINK CLOUDS WILL HANG ON THE LONGEST.
FAR WESTERN AND SOUTHERN AREAS SEEM THE MOST PROBABLE TO
POTENTIALLY CLEAR. WITH RAIN FROM LAST NIGHT AND THEN A COOL HIGH
TEMPERATURE TODAY...SUCH CLEARING WOULD VERY LIKELY FAVOR FOG AND
EVEN DENSE FOG AT THAT. HAVE ADDED THE DENSE POSSIBILITY ONTO THE
GOING FOG WORDING FOR TONIGHT.
WARM AIR ADVECTION THEN ENSUES THURSDAY INTO THE WEEKEND AS THE
CURRENT UPPER LOW OVER THE GULF OF ALASKA BEGINS TO FURTHER A
LONG WAVE TROUGH ACROSS WESTERN NORTH AMERICA. EACH DAY
PROGRESSIVELY WARMS ACROSS THE FORECAST AREA THROUGH
SATURDAY...AND POTENTIALLY EVEN INTO SUNDAY. THE LEAD PUSH OF
ELEVATED MOISTURE AND MORE STOUT WARM AIR ADVECTION ARRIVES FRIDAY
NIGHT INTO EARLY SATURDAY ON A LEAD SHORT WAVE. THICKNESS
DIFFLUENCE AND SURPRISINGLY ELEVATED INSTABILITY ARE REASONABLE
WITH THIS FOR SOME SHOWERS AND EVEN THUNDER...BUT FORECAST DEEP
MOISTURE IS LACKING. THE GOING PLACEMENT OF LOW CHANCE POPS FOR
FRIDAY NIGHT INTO SATURDAY SEEMS VERY GOOD TO CAPTURE THESE
POSSIBILITIES...AND HAVE IN GENERAL MADE FEW CHANGES THERE.
TEMPERATURES ON SATURDAY LOOK TO BE QUITE MILD WITH THE ONLY FLY
IN THE OINTMENT SEEMINGLY IF CLOUDS EARLY HOLD THINGS BACK. BREEZY
SOUTHERLY WINDS WILL ENSUE AS SURFACE CYCLOGENESIS OCCURS FROM THE
CENTRAL PLAINS NORTHEASTWARD. THE 850 MB TEMPS FORECAST BY A
07.00Z EC/GFS BLEND ARE +14C. GIVEN JUST 850MB TEMPS IN EXCESS OF
10C THIS TIME OF YEAR...LOCAL RESEARCH CLIMATOLOGY FOR CHICAGO
SUPPORTS A MEDIAN HIGH OF 67 WITH 70 BEING THE UPPER 25TH
PERCENTILE. SO THE 70 DEGREE MARK IS NOT OUT OF THE QUESTION
ESPECIALLY IF WE START THE DAY SUNNY. SUNDAY IS A BIT MORE
CHALLENGING BUT WILL HAVE AN EVEN WARM STARTING POINT...LIKELY
AROUND 50 DEGREES. SO A FORECAST OF AT LEAST LOWER TO MID 60S
AREA WIDE ON BOTH WEEKEND DAYS HAS PRETTY HIGH CONFIDENCE
ESPECIALLY FOR THIS MANY DAYS OUT THIS TIME OF YEAR.
THE PRECIP CHANCES APPEAR BEST ALONG THE COLD FRONT SUNDAY
AFTERNOON AND NIGHT...WITH THAT FRONTAL TIMING BEING IN GOOD
AGREEMENT ON THE LONG RANGE GUIDANCE. STILL...CANNOT RULE OUT
EARLIER ACTIVITY AS MENTIONED ABOVE AS EARLY AS FRIDAY NIGHT...BUT
EVEN ON SATURDAY NIGHT THE LOW-LEVEL JET WILL BE STRONG ACROSS THE
AREA. HAVE CONTINUED TO INCREASE THE RAIN LIKELIHOOD ON SUNDAY AND
SUNDAY NIGHT...WITH CATEGORICAL POPS NOW IN THE FORECAST. SOME
THUNDER CERTAINLY REMAINS PLAUSIBLE WITH SUCH A DYNAMIC
PROJECTION. COLDER AND THEN DRIER AIR LOOKS TO WRAP IN ON
MONDAY...AND IT WILL BE A BIT OF A RACE TO SEE IF THAT COLDER AIR
WILL CATCH UP TO THE FORCING TO PROVIDE SOME SNOW ON THE BACK
SIDE. AT THIS TIME...THE FORECAST DOES CALL FOR FALLING
TEMPERATURES ON MONDAY WITH NORTHWEST WINDS INCREASING.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* CHANCE FOR LINGERING IFR CIGS/VIS UNTIL ARND 15Z.
* GRADUALLY LIFTING MVFR CIGS THROUGH LATE AFTERNOON/EARLY EVENING.
* MVFR VIS IN -DZ/BR UNTIL EARLY AFTERNOON.
* CHANCE FOR MVFR OR IFR VIS IN BR/FG TONIGHT.
KREIN
//DISCUSSION...UPDATED 12Z...
WEAK...DIFFUSE TROUGH OF LOW PRESSURE SLOWLY SAGING SWD THROUGH
ILLINOIS. LATEST RADAR IMAGERY SHOWS A PATCH OF LIGHT PCPN
WRAPPING AROUND THE LOW CENTER OVER NWRN IN/NERN IL...SO THERE IS
STILL A CHANCE FOR SOME -DZ/-RA AT THE TERMINALS FOR A FEW MORE
HOURS THIS MORNING. LATEST CIG TRENDS SHOW CIGS LIFTING TO
MVFR...BUT THERE WILL STILL BE A CHANCE FOR AT LEAST OCNL IFR THIS
MORNING UNTIL THE SFC LOW MOVES FARTHER SOUTH AND SOME DRIER AIR
CAN ADVECT IN FROM THE NORTH. OTHERWISE...MODEL RH TIMESECTIONS
INDICATE THAT MVFR CIGS SHOULD HOLD IN THROUGH MUCH OF THE DAY. BE
EARLY EVENING...HIGH PRESSURE SHOULD BEGIN TO OVERSPREAD THE
REGION...ALLOWING MUCH OF THE CLOUD COVER TO ERODE...BUT WITH SFC
WINDS REMAINING LIGHT THROUGH THE PERIOD...THERE WILL BE A CHANCE
FOR VIS TO DROP TO MVFR OR IFR OVERNIGHT TONIGHT WITH BR/FG
DEVELOPMENT LIKELY. EXACTLY HOW LOW VIS WILL DROP TONIGHT IS STILL
QUESTIONABLE AND WILL DEPEND ON HOW MUCH HIGH CLOUD COVER WILL BE
PRESENT.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN CIG/VIS TRENDS THIS MORNING.
* LOW CONFIDENCE IN IFR POTENTIAL OVERNIGHT TONIGHT.
* HIGH CONFIDENCE IN PCPN TRENDS THIS MORNING.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...SLIGHT LATE.
SATURDAY...CHANCE RA .
SUNDAY...LIKELY SHRA WITH CHC TSRA. MVFR/IFR POSSIBLE.
MONDAY...CHC RAIN CHANGING TO SNOW. MVFR/IFR POSSIBLE.
TUESDAY...VFR.
KREIN
&&
.MARINE...
300 AM CST
A WEAK TROUGH OF LOW PRESSURE OVER ILLINOIS THROUGH THE WESTERN
GREAT LAKES COMBINED WITH HIGH PRESSURE OVER SOUTHEASTERN CANADA
HAS GENERATED 10 TO 20 KT SOUTHEAST WINDS. WINDS WILL WEAKEN
TONIGHT AS A RIDGE OF HIGH PRESSURE OF BUILDS EASTWARD TO THE
WESTERN GREAT LAKES. MEANWHILE...LOW PRESSURE IS FORECAST TO
DEVELOP OVER THE CENTRAL PLAINS FRIDAY NIGHT AND TRACK NORTHEAST
TO WESTERN LAKE SUPERIOR BY SUNDAY MORNING. A SOUTHERLY PRESSURE
GRADIENT WILL STRENGTHEN OVER THE LAKE AS THE LOW TRACKS
NORTHEASTWARD...WITH SOUTH WINDS INCREASING TO 15 TO 25 KT FOR
THURSDAY AND FRIDAY. WINDS SHOULD STRENGTHEN AT LEAST 30KT FOR
SATURDAY THROUGH EARLY SUNDAY AS THE LOW INTENSIFIES SOME WHILE TRACKING
THROUGH THE UPPER MISSISSIPPI VALLEY. THERE IS A CHANCE FOR SOUTH
GALES DURING THIS PERIOD. BY LATE SUNDAY...THE LOW WILL TRACK TO
JAMES BAY WHILE DRAGGING A STRONG COLD FRONT ACROSS THE
LAKE...BRINGING A QUICK SHIFT TO NORTHWESTERLY WINDS AND A RAPID
INFLUX OF MUCH COLDER AIR.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
326 AM CST WED NOV 7 2012
.DISCUSSION...
322 AM CST
THE IMMEDIATE FORECAST CHALLENGES ARE LINGERING DRIZZLE/LIGHT
RAIN AND ALSO CLOUDS...WITH THE LATTER REMAINING POTENTIALLY INTO
THURSDAY. THEN ATTENTION TURNS TO WHAT DEGREE OF WARM-UP WILL BE
REALIZED AS THE PATTERN BECOMES MORE AMPLIFIED...PROVIDING THE
FINAL CHALLENGE OF PRECIP CHANCES THIS WEEKEND INTO EARLY NEXT
WEEK.
A BROAD UPPER TROUGH WITH DISTINCT POTENT SHORT WAVES HAS EVOLVED
OVER THE EASTERN U.S. FROM LATE YESTERDAY AFTERNOON INTO THIS
MORNING. FINAL SHORT WAVE IS PROGRESSING SOUTHEASTWARD ACROSS
CENTRAL IL EARLY THIS MORNING. STRONG 120+ KNOT NORTH-TO-SOUTH JET
IS LINED UP OVER THE MISSISSIPPI RIVER VALLEY AND WILL HELP TO
PROGRESS THIS SOUTH. THE AREA WILL REMAIN ON THE CYCLONIC SIDE OF
THIS STRONG JET THROUGH TODAY...AND ASSOCIATED MID-LEVEL SHEAR
VORTICITY WILL NOT OFFER MUCH FOR SUPPRESSION TO HELP SCOUR
CLOUDS. AND THOSE CLOUDS ARE WIDESPREAD ON THE EARLY MORNING
11-3.9 MICRON CHANNEL. LAST NIGHTS RAOBS AND EARLY MORNING AMDAR
SOUNDINGS INDICATE THE MOISTURE TO BE SIGNIFICANTLY
DEEP...GENERALLY AROUND 15KFT. IN ADDITION...WITH THE BAGGY LOW-
LEVEL TROUGH DRAPED FROM WI THROUGH THE LOWER APPALACHIANS THIS
MORNING...THE WIND FLOW IS SOMEWHAT LIGHT AND CERTAINLY NOT
ALLOWING FOR ANY DRY AIR ADVECTION INTO THE AREA. MOST MODELS SEEM
TOO QUICK TO BREAK UP A LOT OF THE CLOUDS IN THEIR HUMIDITY
SOLUTIONS...BUT THEY DO AGREE ON A LIGHT WIND FIELD BY AFTERNOON
AND EVENING...NOT SUPPORTIVE OF DISSIPATION OF SUCH A DEEP CLOUD
LAYER. SO FAVOR THE SLOWER NAM SCOURING AND HAVE INCREASED THE
DURATION OF THE CLOUDS BY QUITE A WHILE...EXTENDING THEM INTO
TONIGHT FOR MOST PLACES. SOUTHWEST WINDS BEGIN TO KICK IN ALOFT
TOWARD DAYBREAK THU AND INCREASE THEREAFTER...WHICH SHOULD ALLOW
FOR THE LINGERING CLOUDS TO SCATTER AND ADVECT OFF TO THE
NORTHEAST THROUGHOUT THURSDAY MORNING.
ANY PRECIPITATION FOR TODAY SHOULD MAINLY BE CONFINED TO THIS
MORNING. CONTINUED GENTLE ISENTROPIC ASCENT ON THE 280K LAYER IS
ANALYZED BY THE RAP MODEL EXACTLY WHERE RADAR DEPICTS DRIZZLE AND
LIGHT RAIN ACROSS NE IL AND NW IN EARLY THIS MORNING. THIS SUPPORT
FADES SLOWLY THROUGH THE MORNING...AND NOT REALLY UNTIL LATE
MORNING AT THAT. MULTIPLE SHORT TERM MODELS SUPPORT THIS DOWNWARD
TREND ON REFLECTIVITY. SO HAVE SOME MENTION FOR DRIZZLE WITH
POCKETS OF LIGHT RAIN.
TEMPERATURES TODAY SHOULD STRUGGLE TO CLIMB MUCH. THE CLOUDS WITH
THE LOW ANGLE SUN AT THIS TIME OF YEAR SHOULD ALLOW FOR A DIURNAL
SPREAD FAR LOWER THAN THE NORMAL 16-18 DEGREES THIS TIME OF YEAR.
THIS MORNING ALONE PLACES MAY ONLY CLIMB A COUPLE DEGREES AT MOST.
THE TEMPERATURES TONIGHT ARE A BIG CHALLENGE AND DEPENDING ON
CLOUD COVER COULD VARY UP TO 15 DEGREES OR SO. HAVE TRENDED
WARMER FOR AREAS WHERE WE THINK CLOUDS WILL HANG ON THE LONGEST.
FAR WESTERN AND SOUTHERN AREAS SEEM THE MOST PROBABLE TO
POTENTIALLY CLEAR. WITH RAIN FROM LAST NIGHT AND THEN A COOL HIGH
TEMPERATURE TODAY...SUCH CLEARING WOULD VERY LIKELY FAVOR FOG AND
EVEN DENSE FOG AT THAT. HAVE ADDED THE DENSE POSSIBILITY ONTO THE
GOING FOG WORDING FOR TONIGHT.
WARM AIR ADVECTION THEN ENSUES THURSDAY INTO THE WEEKEND AS THE
CURRENT UPPER LOW OVER THE GULF OF ALASKA BEGINS TO FURTHER A
LONG WAVE TROUGH ACROSS WESTERN NORTH AMERICA. EACH DAY
PROGRESSIVELY WARMS ACROSS THE FORECAST AREA THROUGH
SATURDAY...AND POTENTIALLY EVEN INTO SUNDAY. THE LEAD PUSH OF
ELEVATED MOISTURE AND MORE STOUT WARM AIR ADVECTION ARRIVES FRIDAY
NIGHT INTO EARLY SATURDAY ON A LEAD SHORT WAVE. THICKNESS
DIFFLUENCE AND SURPRISINGLY ELEVATED INSTABILITY ARE REASONABLE
WITH THIS FOR SOME SHOWERS AND EVEN THUNDER...BUT FORECAST DEEP
MOISTURE IS LACKING. THE GOING PLACEMENT OF LOW CHANCE POPS FOR
FRIDAY NIGHT INTO SATURDAY SEEMS VERY GOOD TO CAPTURE THESE
POSSIBILITIES...AND HAVE IN GENERAL MADE FEW CHANGES THERE.
TEMPERATURES ON SATURDAY LOOK TO BE QUITE MILD WITH THE ONLY FLY
IN THE OINTMENT SEEMINGLY IF CLOUDS EARLY HOLD THINGS BACK. BREEZY
SOUTHERLY WINDS WILL ENSUE AS SURFACE CYCLOGENESIS OCCURS FROM THE
CENTRAL PLAINS NORTHEASTWARD. THE 850 MB TEMPS FORECAST BY A
07.00Z EC/GFS BLEND ARE +14C. GIVEN JUST 850MB TEMPS IN EXCESS OF
10C THIS TIME OF YEAR...LOCAL RESEARCH CLIMATOLOGY FOR CHICAGO
SUPPORTS A MEDIAN HIGH OF 67 WITH 70 BEING THE UPPER 25TH
PERCENTILE. SO THE 70 DEGREE MARK IS NOT OUT OF THE QUESTION
ESPECIALLY IF WE START THE DAY SUNNY. SUNDAY IS A BIT MORE
CHALLENGING BUT WILL HAVE AN EVEN WARM STARTING POINT...LIKELY
AROUND 50 DEGREES. SO A FORECAST OF AT LEAST LOWER TO MID 60S
AREA WIDE ON BOTH WEEKEND DAYS HAS PRETTY HIGH CONFIDENCE
ESPECIALLY FOR THIS MANY DAYS OUT THIS TIME OF YEAR.
THE PRECIP CHANCES APPEAR BEST ALONG THE COLD FRONT SUNDAY
AFTERNOON AND NIGHT...WITH THAT FRONTAL TIMING BEING IN GOOD
AGREEMENT ON THE LONG RANGE GUIDANCE. STILL...CANNOT RULE OUT
EARLIER ACTIVITY AS MENTIONED ABOVE AS EARLY AS FRIDAY NIGHT...BUT
EVEN ON SATURDAY NIGHT THE LOW-LEVEL JET WILL BE STRONG ACROSS THE
AREA. HAVE CONTINUED TO INCREASE THE RAIN LIKELIHOOD ON SUNDAY AND
SUNDAY NIGHT...WITH CATEGORICAL POPS NOW IN THE FORECAST. SOME
THUNDER CERTAINLY REMAINS PLAUSIBLE WITH SUCH A DYNAMIC
PROJECTION. COLDER AND THEN DRIER AIR LOOKS TO WRAP IN ON
MONDAY...AND IT WILL BE A BIT OF A RACE TO SEE IF THAT COLDER AIR
WILL CATCH UP TO THE FORCING TO PROVIDE SOME SNOW ON THE BACK
SIDE. AT THIS TIME...THE FORECAST DOES CALL FOR FALLING
TEMPERATURES ON MONDAY WITH NORTHWEST WINDS INCREASING.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* IFR CIGS WITH BASES AT OVC006-OO8 THROUGH LATE MORNING.
* CIGS IMPROVING TO LOWER RANGE MVFR BY LATE MORNING AND REMAINING
THERE THROUGH EARLY EVENING...CHANCE CIGS MAY REMAIN IFR LONGER.
* VIS OF 2-4SM IN -DZ/BR...CHANCE VIS COULD LOWER TO 1SM UNTIL
DAYBREAK.
* VIS IMPROVING TO MVFR BY LATE MORNING...THROUGH LATE
AFTERNOON...CHANCE THAT VIS MAY REMAIN MVFR LONGER.
KREIN
//DISCUSSION...UPDATED 06Z...
WEAK...DIFFUSE TROUGH OF LOW PRESSURE REMAINS PARKED OVER THE
REGION WITH HIGH LEVELS OF LOW LEVEL MOISTURE IN PLACE. WITH SFC
WINDS AT 5KT OR LESS AND SOME INTRUSION OF DRIER AIR AT MID
LEVELS...PCPN IS TRANSIONING OVER TO DRIZZLE...WHILE CIGS REMAIN
AT IFR LEVELS. BASES ARE OVC006-008 AT ORD/MDW...BUT BASES ARE
LOWER...OVC003-004 OVER THE MORE RURAL AREAS...INCLUDING RFD.
EXPECT CONDITIONS TO REMAIN RELATIVELY STAGNANT OVERNIGHT AND INTO
THE DAYLIGHT HOURS WITH LITTLE IMPROVEMENT. THERE SHOULD BE SOME
IMPROVEMENT BY LATE MORNING/EARLY AFTERNOON AS LOW LEVEL FLOW
TRENDS MORE NORTHERLY...WITH A PUSH OF COOLER...DRIER AIR AT THE
SFC BY LATE AFTERNOON/EARLY EVENING. THERE IS SOME UNCERTAINTY TO
THE DEGREE OF LOW LEVEL DRYING THIS AFTERNOON...AND THERE REMAINS
A CHANCE THAT THE IFR CONDITIONS MAY HANG IN LONGER THAN INITIALLY
ANTICIPATED. IT IS A BIT MORE CERTAIN THAT MVFR CONDITIONS SHOULD
PERSIST AT LEAST INTO THE EARLY EVENING HOURS.
WITH A WEAK PRESSURE PATTERN EXPECTED TO REMAIN IN PLACE THROUGH
THE PERIOD...WINDS SHOULD REMAIN BELOW 10KT. DIRECTION IS LESS
DEFINITIVE IN THE WEAK GRADIENT SITUATION...BUT SHOULD GENERALLY
BE SELY THROUGH THE NIGHT AND THEN GRADUALLY BECOMING MORE NLY-
NELY THROUGH THE DAY TOMORROW.
BY TOMORROW EVENING...WEAK HIGH PRESSURE SHOULD SPREAD EASTWARD
OUT OF THE CNTRL PLAINS AND INTO THE MIDWEST AND WESTERN GREAT
LAKES REGIONS TOMORROW EVENING. THIS WILL KEEP WINDS ACROSS THE
AREA LIGHT...BUT SKY COVER SHOULD CLEAR OUT. FOG DEVELOPMENT WILL
BECOME A CONCERN OVERNIGHT TOMORROW...BUT WILL BE DEPENDENT ON
THE EXTENT OF CLEARING SKIES. AT THIS TIME...WILL WILL REINTRODUCE
3-4SM VIS INTO THE TAFS FOR TOMORROW NIGHT...BUT THERE IS THE
POTENTIAL FOR IFR VIS IN FG/BR.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN IFR CIGS/VSBY THROUGH MID MORNING...WITH A
CHANCE THAT CONDITIONS MAY DROP TO LIFR FOR BRIEF PERIODS BEFORE
DAYBREAK.
* LOW CONFIDENCE IN TIMING OF IMPROVEMENT TO MVFR LEVELS DURING
THE DAY TOMORROW.
* LOW CONFIDENCE IN TIMING OF IMPROVEMENT TO VFR. THERE IS A
CHANCE THAT WHEN CIGS IMPROVE TO VFR THAN VIS MAY DROP TO MVFR
IR IFR IN BR/FG DEVELOPMENT TOMORROW NIGHT.
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...VFR.
SATURDAY...SLT CHC RA.
SUNDAY...LIKELY SHRA WITH CHC TSRA. MVFR/IFR POSSIBLE.
MONDAY...CHC RAIN CHANGING TO SNOW. MVFR/IFR POSSIBLE.
BMD
&&
.MARINE...
300 AM CST
A WEAK TROUGH OF LOW PRESSURE OVER ILLINOIS THROUGH THE WESTERN
GREAT LAKES COMBINED WITH HIGH PRESSURE OVER SOUTHEASTERN CANADA
HAS GENERATED 10 TO 20 KT SOUTHEAST WINDS. WINDS WILL WEAKEN
TONIGHT AS A RIDGE OF HIGH PRESSURE OF BUILDS EASTWARD TO THE
WESTERN GREAT LAKES. MEANWHILE...LOW PRESSURE IS FORECAST TO
DEVELOP OVER THE CENTRAL PLAINS FRIDAY NIGHT AND TRACK NORTHEAST
TO WESTERN LAKE SUPERIOR BY SUNDAY MORNING. A SOUTHERLY PRESSURE
GRADIENT WILL STRENGTHEN OVER THE LAKE AS THE LOW TRACKS
NORTHEASTWARD...WITH SOUTH WINDS INCREASING TO 15 TO 25 KT FOR
THURSDAY AND FRIDAY. WINDS SHOULD STRENGTHEN AT LEAST 30KT FOR
SATURDAY THROUGH EARLY SUNDAY AS THE LOW INTENSIFIES SOME WHILE TRACKING
THROUGH THE UPPER MISSISSIPPI VALLEY. THERE IS A CHANCE FOR SOUTH
GALES DURING THIS PERIOD. BY LATE SUNDAY...THE LOW WILL TRACK TO
JAMES BAY WHILE DRAGGING A STRONG COLD FRONT ACROSS THE
LAKE...BRINGING A QUICK SHIFT TO NORTHWESTERLY WINDS AND A RAPID
INFLUX OF MUCH COLDER AIR.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
259 PM CST WED NOV 7 2012
.SYNOPSIS...
LATEST SFC ANALYSIS WAS INDICATING RIDGE AXIS CONTINUING TO SLIDE
ACRS THE EASTERN PLAINS INTO THE WESTERN GRT LKS. CENTRAL TO
NORTHERN PLAINS RIFE WITH PRESSURE FALLS AND LLVL RETURN FLOW...
TEMPS IN THE 50S AND 60S. 12Z UPPER AIR ANALYSIS AND MID/HIGH LEVEL
MOISTURE FLOW PATTERNS ON CURRENT WATER VAPOR LOOP SHOW PREVIOUSLY
PRONOUNCED UPPER RIDGE ACRS THE ROCKIES GETTING PRESSED EASTWARD
ACRS THE NORTHERN PLAINS BY SURGE OF PACIFIC NW UPPER JET ENERGY.
OTHER UPPER JET MAX OVER THE ARE THIS MORNING STARTING TO DEPART OFF
TO THE SOUTHEAST INTO EAST COAST L/W TROF BASE.
&&
.SHORT TERM...TONIGHT AND THURSDAY...
TONIGHT...MAIN CHALLENGE TONIGHT CONTINUES TO BE WHAT WILL HAPPEN TO
ONGOING CLOUD DECK ALIGNED ACRS MUCH OF THE UPPER TO MID MS RVR
VALLEY REGIONS. DEPARTING UPPER JET TO THE SE AND ARRIVAL OF UPSTREAM
RIDGE GETTING PRESSED ACRS THE AREA WILL CONTINUE TO ENHANCE ONGOING
SUBSIDENCE REGIME WHICH NORMALLY WOULD MEAN A CLOUD DECAY/CLEAR OUT.
BUT FCST SOUNDINGS AND UPPER AIR SOUNDINGS SUGGEST TRAPPING INVERSION
ALOFT TO GET ENHANCED BY THE SAME PROCESSES THIS EVENING AND INTO
THE OVERNIGHT...WHICH COULD TRAP THE CLOUD COVER AND LIMIT CLEAR OUT
TRENDS INTO EARLY THU MORNING. LATEST RAP RUNS IN HANDLING MOISTURE
IN THE H95-H85 MB LAYER ALSO POINT TO THE LOW CLOUDS GETTING TRAPPED
ALONG AND EAST OF THE MS RVR THROUGH AT LEAST MIDNIGHT BEFORE SOME
CLEARING PUSH INCREASE FROM THE WEST AFTER 09Z TONIGHT. WEST OF THE
MS RVR...EXPECT PREVIOUS CLEARING HOLES THAT DIURNALLY FILLED WITH
CUMULUS TO CLEAR OUT AGAIN AFTER SUNSET...MAKING FOR A PATCHY
CLEARING PATTERN ACRS THE WESTERN HALF OF THE CWA AS THE EVENING
PROGRESSES. WILL PLAY THE CLOUDS A BIT MORE PESSIMISTIC IN THE FCST
AND HANG THEM ON ESPECIALLY ACRS THE EASTERN HALF OF THE CWA WELL
PAST MIDNIGHT...WITH SOME CLEARING TRENDS TOWARD SUNRISE THU MORNING.
RIDGE-RIDING CI WILL ALSO SPILL DOWN ACRS THE AREA FROM THE
NORTHWEST. EVEN WITH DELAYED CLEARING TRENDS IN MIND...ONGOING LOWS
GENERALLY STILL LOOK ON TARGET EXCEPT MAYBE A MINOR ADJUSTMENT UPWARD
ACRS THE FAR EASTERN CWA. WITH LIGHT WINDS AND POSSIBLE CLEARING
HOLES UNDER RIDGE AXIS...WILL KEEP THE PATCHY FOG MENTION INTRODUCED
BY PREVIOUS SHIFT ACRS GENERALLY THE EASTERN HALF OF THE DVN CWA.
WITH LACK OF CLEARING THIS AFTERNOON ACRS THE WESTERN HALF OF THE CWA
AND THUS LIMITED DRYING...PATCHY FOG WORDING MAYBE WARRANTED FURTHER
TO THE WEST.
THURSDAY...SOME OF THE RETURN FLOW GRADIENT AND SUNSHINE GOING ON
NOW ACRS THE EAST-CENTRAL PLAINS WILL MAKE ITS WAY ACRS THE LOCAL
AREA. INCREASING SOUTHERLY WINDS AND LLVL WARM AIR ADVECTION SHOULD
TRANSLATE LOCALLY TO WHAT IS CURRENTLY GOING ON ACRS EASTERN NEB AND
FAR WESTERN IA...WIDESPREAD MID TO UPPER 50S WITH A CHANCE AT A 60
DEGREE READING BY LATE THU AFTERNOON. ..12..
.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...
NEAR RECORD WARMTH FRIDAY AND SATURDAY...THEN SIGNIFICANT RAINS WITH
A STRONG COLD FRONTAL PASSAGE SUNDAY THE MAIN FORECAST ISSUES.
OVERVIEW...LIMITED UPSTREAM SENSIBLE WEATHER INITIALIZATION ISSUES
WITH D_PROG_DT AND MOISTURE BIASES SUPPORTING WITH COLD FRONT USING
GFS AS THE PRIMARY TOOL. THIS SUPPORTS WIDESPREAD SEASONABLE HEAVY
RAINFALL TOTALS OF .5+ OF AN INCH...UP TO LOCALLY 2.0 INCHES.
THURSDAY NIGHT THROUGH FRIDAY...FAIR SKIES WITH INCREASING SOUTH
WINDS THAT WILL BECOME BREEZY BY FRIDAY PM. NEARLY STEADY TO
POSSIBLY SLOWLY RISING MINS IN THE 30S THURSDAY AM. THEN HIGHS IN
THE UPPER 50S NE TO LOWER 60S SW WITH POSSIBLY HIGHER VALUES IF
ENOUGH SUNSHINE AND BL MIXING OCCURS. FRIDAY NIGHT...VERY MILD WITH
MINS WITHIN 5 DEGREES OF RECORD WARM MINS RANGING FROM UPPER 40S NE
TO THE LOWER TO MIDDLE 50S SW SECTIONS. LOTS OF HIGH CLOUDS SHOULD
ARRIVE INTO THE AREA FRIDAY NIGHT.
SATURDAY AND SATURDAY NIGHT...STRONG WAA TO KEEP REGION WELL ABOVE
NORMAL WITH TEMPERATURES WITHIN 5 DEGREES OF RECORDS. KEPT VERY LOW
POPS WITH LIGHT -SHRA POSSIBLE WITH HIGH PW/S AND WEAK UPPER LEVEL
DISTURBANCES INTERACTING WITH LOW LEVEL JET. LOCAL TOOLS SUPPORT
LOWER 70S POSSIBLE WITH ENOUGH SUNSHINE FOR HIGHS AND MINS ONCE AGAIN
IN THE LOWER/MIDDLE 50S.
SUNDAY AND SUNDAY NIGHT...STRONG COLD FRONT TO PASS WITH TEMPERATURES
CRASHING 25-30+ PLUS DEGREES WITHIN 6 HOURS OF THE FRONT PASSING.
SIGNIFICANT BANDS OF MODERATE TO LOCALLY HEAVY RAIN/RAINSHOWERS AND
SOME EMBEDDED BRIEF THUNDER ALONG AND JUST BEHIND THE FRONT. EXPECT
A LARGE GRADIENT FOR MAX TEMPERATURES. GONE WITH NEAR 50F FAR NW TO
THE MIDDLE 60S FAR SW SECTIONS. LIKELY THIS GRADIENT WILL BE GREATER
ONCE TIMING ISSUE BETTER RESOLVED IN THE NEXT COUPLE OF DAYS. PW
VALUES NEAR 1.5 INCHES AHEAD OF FRONT PER LOCAL TECHNIQUES CONFIRM
AT LEAST .5 INCHES OF RAINFALL WITH 1.5+ INCHES WITH TRAINING AND
EVEN HIGHER POSSIBLE WITH ANY WAVE ON THE FRONT.
MONDAY THROUGH WEDNESDAY...FAIR SKIES AND SEASONABLY COLD WITH BELOW
NORMAL TEMPERATURES. HIGHS MOSTLY IN THE MID 30S TO LOWER 40S AND
MINS IN THE 20S...POSSIBLY UPPER TEENS IN FAVORED LOW LYING
LOCATIONS.
NICHOLS
&&
.AVIATION...
HIGH PRESSURE ACRS THE MO RVR VALLEY REGION WILL CONTINUE TO BUILD
EASTWARD ACRS THE AREA THROUGH THIS EVENING. MAINLY MVFR CIGS OF
BKN-OVC COVERAGE WILL CONTINUE INTO THE EVENING BEFORE CLEARING IS
EXPECTED FROM THE WEST ESPECIALLY AT THE CID SITE. THE THREAT FOR
SOME CLOUDS TO REMAIN WELL INTO THE NIGHT TRAPPED UNDER SUBSIDENCE
INVERSION REMAINS...ESPECIALLY ALONG AND EAST OF THE MS RVR.
NORTHERLY WINDS 6-12 KTS WILL BECOME CALM OR LIGHT AND VARIABLE THIS
EVENING INTO THE OVERNIGHT WITH THE SFC RIDGE OVERHEAD. PATCHY FOG
STILL APPEARS POSSIBLE LATE TONIGHT WITH VSBYS MAINLY BETWEEN 3-6SM
IN AREAS THAT DO CLEAR OUT. SOUTH WINDS INCREASING TO 10+ KTS BY MID
THU MORNING WITH JUST SOME CIRRUS CLOUDS OVERHEAD. ..12..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
12/NICHOLS
AREA FORECAST DISCUSSION...UPDATED
NWS DES MOINES IA
1134 AM CST WED NOV 7 2012
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
MAIN CONCERNS TODAY WILL BE PRECIP TRENDS EARLY FOLLOWED BY TEMPS
AND CLOUDS. SHORT WAVE/PV ANOMALY TRACKING DOWN MID MS RIVER SHOWS
UP NICELY IN WATER VAPOR IMAGERY. DEEPER FORCING AND CLOUDS
ASSOCIATED WITH FEATURE WILL REMAIN EAST OF IA INTO IL. HOWEVER
STRATUS LINGERS ACROSS MUCH OF FORECAST AREA WITH MOISTURE 1.5KM
AND BELOW PER FORECAST SOUNDINGS. RADAR AND SURFACE OBS CONTINUE
TO DEPICT PATCHY DRIZZLE AND/OR VERY LIGHT RAIN...HOWEVER RAP 280K
ISENT LAYER SUGGESTS UVM AND MOISTURE WILL DIMINISH SUFFICIENTLY
THAT THIS SHOULD END BY 12Z.
SOUNDINGS SHOW MOISTURE CONTINUING TO DECREASE AND THIN THROUGH THE
DAY WITH CLOUDS BECOMING CELLULAR IN SHALLOW MIXING. WINDS WILL
BECOME FAIRLY LIGHT AS RIDGE APPROACHES WITH SOUNDINGS ONLY
SUPPORTING HIGHS FROM THE MIDDLE 40S NE TO LOWER 50S SW.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
MODELS REMAIN IN VERY GOOD AGREEMENT WITH WARM UP LATE THIS WEEK AND
INTO THE SATURDAY...THEN WITH TIMING OF STRONG UPPER LEVEL TROUGH
AND SURFACE LOW PRESSURE PUSHING ACROSS THE STATE ON SUNDAY. LEANED
TOWARD A NAM/GFS BLEND THROUGH SATURDAY...THEN GFS/ECMWF BLEND
SUNDAY INTO EARLY NEXT WEEK.
TONIGHT THROUGH FRIDAY...ABOVE NORMAL TEMPS STILL THE MAIN CONCERN
DURING THIS PERIOD WITH RETURN FLOW DEVELOPING TONIGHT AS THE
SURFACE HIGH SHIFTS EAST. GOOD WAA AND ENOUGH MIXING WILL PUT TEMPS
NEAR 60 ACROSS THE CENTRAL TO SOUTHWEST THURSDAY. 850MB TEMPS WARM
TO +10-12C BY THURSDAY AFTERNOON...ALTHOUGH MIXING LOOKS TO BE ONLY
UP TO 900MB ACCORDING TO THE NAM/GFS BUFR SOUNDINGS. THE WAA
CONTINUES THROUGH FRIDAY...BUT WITH A DECENT AMOUNT OF MID-LEVEL
THETA-E ADVECTION AND INCREASED MOISTURE TRANSPORT ALONG THE 295K TO
305K ISENTROPIC SURFACES...CLOUD COVER MAY PLAY A ROLE IN THE MAX
TEMPS. THINKING WITH THE WARM START FRIDAY MORNING...COMBINED WITH
THE SURGE OF SURFACE DEW POINTS INTO THE 45 TO 55 DEGREE
RANGE...FELT CONFIDENT ENOUGH TO BUMP MAX TEMPS UP A DEGREE ACROSS
THE SOUTH AND WEST EVEN WITH THE CLOUD COVER PRESENT. KEPT ONGOING
FORECAST HIGHS FOR THE NORTH AND EAST.
SOUNDINGS INDICATIVE OF DRIZZLE BY FRIDAY NIGHT ACROSS NORTHERN
IOWA WITH SOME WEAK ISENTROPIC LIFT PRESENT TO WARRANT THE MENTION
OF DRIZZLE IN NORTHERN IOWA. GFS IS A LITTLE QUICKER WITH
SATURATION BELOW 800MB AT MCW/ALO/DSM. SO KEPT WITH SLIGHT POPS
B/T 00-12Z SATURDAY. MODELS STILL DEPICTING SOME ELEVATED
INSTABILITY FRIDAY AFTERNOON INTO THE EVENING AND KEPT MENTION OF
ISOLATED THUNDER IN THE SOUTH-CENTRAL.
SATURDAY AND SUNDAY...HAVE LINGERING POPS ACROSS THE EAST WITH WARM
FRONT SURGING INTO MN/WI AREA. DECREASED POPS DURING THE DAY
SATURDAY WITH STRONG CAP IN PLACE AND NO TRIGGER UNTIL THE COLD
FRONT ENTERS THE STATE SATURDAY NIGHT. VERY STRONG MIXING AND WAA
THROUGHOUT THE DAY SATURDAY AND LIMITED CLOUD COVER ACROSS THE
SOUTHWEST...TWEAKED MAX TEMPS UP SLIGHTLY. MODELS HAVE BACK OFF SOME
ON THE VERY GUSTY WINDS...BUT STILL EXPECTING A WINDY AFTERNOON
SATURDAY.
FRONT LOOKS TO ENTER THE NORTHWEST PORTION OF THE FORECAST AREA BY
06Z SUNDAY...AND CLEAR THE SOUTHEAST SHORTLY AFTER 18Z SUNDAY.
BEST FORCING AND DEEPEST MOISTURE WILL BE ALONG AND JUST AHEAD
THE FRONT SATURDAY NIGHT INTO SUNDAY MORNING. HAVE KEPT WITH
HIGHEST POPS DURING THIS TIME FRAME. COLUMN LOSES ICE INTRODUCTION
SUNDAY AFTERNOON AND MAY SEE DRIZZLE/FZDZ INTO SUNDAY EVENING WITH
THE STRONG CAA INTO THE STATE. LOW CONFIDENCE WITH MENTION ATTM.
MONDAY INTO TUESDAY...CAA CONTINUES INTO SUNDAY AND LIKELY WILL SEE
SOME LINGERING STRATUS ACROSS THE NORTH THROUGH MONDAY AFTERNOON.
SOUNDING NOT DEPICTING THIS SCENARIO VERY WELL...BUT GFS/ECMWF
SHOWING SOME MID-LEVEL RH GREATER THAN 80 PERCENT THROUGH 18Z
MONDAY. REGARDLESS...MONDAY HIGH TEMPS MAY NOT GET ABOVE FREEZING IN
NORTHERN IOWA.
&&
.AVIATION...07/18Z
STRATOCUMULUS CLOUDS HAVE EXPANDED ACROSS MUCH OF THE AREA THIS
MORNING...PRODUCING BORDERLINE MVFR CIGS AT THE TERMINALS. EXPECT
THESE CLOUDS TO PERSIST THROUGH THE AFTERNOON BUT WITH BASES SLOWLY
RISING...AND HAVE CONFINED TEMPO MVFR CIGS TO THE FIRST HOUR OR TWO
OF THE TAFS. BY EVENING THE CLOUDS WILL CLEAR OUT AS A RIDGE BUILDS
IN FROM THE WEST...WITH VFR CONDITIONS PREVAILING FOR THE REMAINDER
OF THE TAF PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...PODRAZIK
AVIATION...LEE
AREA FORECAST DISCUSSION
NWS DES MOINES IA
545 AM CST WED NOV 7 2012
.SHORT TERM /TODAY/...
MAIN CONCERNS TODAY WILL BE PRECIP TRENDS EARLY FOLLOWED BY TEMPS
AND CLOUDS. SHORT WAVE/PV ANOMALY TRACKING DOWN MID MS RIVER SHOWS
UP NICELY IN WATER VAPOR IMAGERY. DEEPER FORCING AND CLOUDS
ASSOCIATED WITH FEATURE WILL REMAIN EAST OF IA INTO IL. HOWEVER
STRATUS LINGERS ACROSS MUCH OF FORECAST AREA WITH MOISTURE 1.5KM
AND BELOW PER FORECAST SOUNDINGS. RADAR AND SURFACE OBS CONTINUE
TO DEPICT PATCHY DRIZZLE AND/OR VERY LIGHT RAIN...HOWEVER RAP 280K
ISENT LAYER SUGGESTS UVM AND MOISTURE WILL DIMINISH SUFFICIENTLY
THAT THIS SHOULD END BY 12Z.
SOUNDINGS SHOW MOISTURE CONTINUING TO DECREASE AND THIN THROUGH THE
DAY WITH CLOUDS BECOMING CELLULAR IN SHALLOW MIXING. WINDS WILL
BECOME FAIRLY LIGHT AS RIDGE APPROACHES WITH SOUNDINGS ONLY
SUPPORTING HIGHS FROM THE MIDDLE 40S NE TO LOWER 50S SW.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
MODELS REMAIN IN VERY GOOD AGREEMENT WITH WARM UP LATE THIS WEEK AND
INTO THE SATURDAY...THEN WITH TIMING OF STRONG UPPER LEVEL TROUGH
AND SURFACE LOW PRESSURE PUSHING ACROSS THE STATE ON SUNDAY. LEANED
TOWARD A NAM/GFS BLEND THROUGH SATURDAY...THEN GFS/ECMWF BLEND
SUNDAY INTO EARLY NEXT WEEK.
TONIGHT THROUGH FRIDAY...ABOVE NORMAL TEMPS STILL THE MAIN CONCERN
DURING THIS PERIOD WITH RETURN FLOW DEVELOPING TONIGHT AS THE
SURFACE HIGH SHIFTS EAST. GOOD WAA AND ENOUGH MIXING WILL PUT TEMPS
NEAR 60 ACROSS THE CENTRAL TO SOUTHWEST THURSDAY. 850MB TEMPS WARM
TO +10-12C BY THURSDAY AFTERNOON...ALTHOUGH MIXING LOOKS TO BE ONLY
UP TO 900MB ACCORDING TO THE NAM/GFS BUFR SOUNDINGS. THE WAA
CONTINUES THROUGH FRIDAY...BUT WITH A DECENT AMOUNT OF MID-LEVEL
THETA-E ADVECTION AND INCREASED MOISTURE TRANSPORT ALONG THE 295K TO
305K ISENTROPIC SURFACES...CLOUD COVER MAY PLAY A ROLE IN THE MAX
TEMPS. THINKING WITH THE WARM START FRIDAY MORNING...COMBINED WITH
THE SURGE OF SURFACE DEW POINTS INTO THE 45 TO 55 DEGREE
RANGE...FELT CONFIDENT ENOUGH TO BUMP MAX TEMPS UP A DEGREE ACROSS
THE SOUTH AND WEST EVEN WITH THE CLOUD COVER PRESENT. KEPT ONGOING
FORECAST HIGHS FOR THE NORTH AND EAST.
SOUNDINGS INDICATIVE OF DRIZZLE BY FRIDAY NIGHT ACROSS NORTHERN
IOWA WITH SOME WEAK ISENTROPIC LIFT PRESENT TO WARRANT THE MENTION
OF DRIZZLE IN NORTHERN IOWA. GFS IS A LITTLE QUICKER WITH
SATURATION BELOW 800MB AT MCW/ALO/DSM. SO KEPT WITH SLIGHT POPS
B/T 00-12Z SATURDAY. MODELS STILL DEPICTING SOME ELEVATED
INSTABILITY FRIDAY AFTERNOON INTO THE EVENING AND KEPT MENTION OF
ISOLATED THUNDER IN THE SOUTH-CENTRAL.
SATURDAY AND SUNDAY...HAVE LINGERING POPS ACROSS THE EAST WITH WARM
FRONT SURGING INTO MN/WI AREA. DECREASED POPS DURING THE DAY
SATURDAY WITH STRONG CAP IN PLACE AND NO TRIGGER UNTIL THE COLD
FRONT ENTERS THE STATE SATURDAY NIGHT. VERY STRONG MIXING AND WAA
THROUGHOUT THE DAY SATURDAY AND LIMITED CLOUD COVER ACROSS THE
SOUTHWEST...TWEAKED MAX TEMPS UP SLIGHTLY. MODELS HAVE BACK OFF SOME
ON THE VERY GUSTY WINDS...BUT STILL EXPECTING A WINDY AFTERNOON
SATURDAY.
FRONT LOOKS TO ENTER THE NORTHWEST PORTION OF THE FORECAST AREA BY
06Z SUNDAY...AND CLEAR THE SOUTHEAST SHORTLY AFTER 18Z SUNDAY.
BEST FORCING AND DEEPEST MOISTURE WILL BE ALONG AND JUST AHEAD
THE FRONT SATURDAY NIGHT INTO SUNDAY MORNING. HAVE KEPT WITH
HIGHEST POPS DURING THIS TIME FRAME. COLUMN LOSES ICE INTRODUCTION
SUNDAY AFTERNOON AND MAY SEE DRIZZLE/FZDZ INTO SUNDAY EVENING WITH
THE STRONG CAA INTO THE STATE. LOW CONFIDENCE WITH MENTION ATTM.
MONDAY INTO TUESDAY...CAA CONTINUES INTO SUNDAY AND LIKELY WILL SEE
SOME LINGERING STRATUS ACROSS THE NORTH THROUGH MONDAY AFTERNOON.
SOUNDING NOT DEPICTING THIS SCENARIO VERY WELL...BUT GFS/ECMWF
SHOWING SOME MID-LEVEL RH GREATER THAN 80 PERCENT THROUGH 18Z
MONDAY. REGARDLESS...MONDAY HIGH TEMPS MAY NOT GET ABOVE FREEZING IN
NORTHERN IOWA.
&&
.AVIATION...07/12Z
WIDESPREAD MVFR OR LOW END VFR CIGS ARE IN PLACE ACROSS CENTRAL AND
EASTERN IA AT 12Z...MAINLY ALONG AND WEST OF KEST/KPRO/KLWD LINE.
CIGS HAVE BEEN GRADUALLY LIFTING EARLY THIS MORNING SO ONLY EXPECT
LINGERING MVFR CIGS TO LINGER FOR A FEW MORE HOURS. OTHERWISE
EXPECT VFR STRATUS INTO MIDDAY...GRADUALLY PUSHING EAST AND BECOMING
MORE SCT/CELLULAR BY AFTERNOON. WINDS WILL BE LIGHT...NW THEN SSE
AS SURFACE RIDGE CROSSES STATE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/AVIATION...SMALL
LONG TERM...PODRAZIK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
338 AM CST WED NOV 7 2012
.SHORT TERM /TODAY/...
MAIN CONCERNS TODAY WILL BE PRECIP TRENDS EARLY FOLLOWED BY TEMPS
AND CLOUDS. SHORT WAVE/PV ANOMALY TRACKING DOWN MID MS RIVER SHOWS
UP NICELY IN WATER VAPOR IMAGERY. DEEPER FORCING AND CLOUDS
ASSOCIATED WITH FEATURE WILL REMAIN EAST OF IA INTO IL. HOWEVER
STRATUS LINGERS ACROSS MUCH OF FORECAST AREA WITH MOISTURE 1.5KM
AND BELOW PER FORECAST SOUNDINGS. RADAR AND SURFACE OBS CONTINUE
TO DEPICT PATCHY DRIZZLE AND/OR VERY LIGHT RAIN...HOWEVER RAP 280K
ISENT LAYER SUGGESTS UVM AND MOISTURE WILL DIMINISH SUFFICIENTLY
THAT THIS SHOULD END BY 12Z.
SOUNDINGS SHOW MOISTURE CONTINUING TO DECREASE AND THIN THROUGH THE
DAY WITH CLOUDS BECOMING CELLULAR IN SHALLOW MIXING. WINDS WILL
BECOME FAIRLY LIGHT AS RIDGE APPROACHES WITH SOUNDINGS ONLY
SUPPORTING HIGHS FROM THE MIDDLE 40S NE TO LOWER 50S SW.
.LONG TERM /TONIGHT THROUGH TUESDAY/...MODELS REMAIN IN VERY GOOD
AGREEMENT WITH WARM UP LATE THIS WEEK AND INTO THE
SATURDAY...THEN WITH TIMING OF STRONG UPPER LEVEL TROUGH AND
SURFACE LOW PRESSURE PUSHING ACROSS THE STATE ON SUNDAY. LEANED
TOWARD A NAM/GFS BLEND THROUGH SATURDAY...THEN GFS/ECMWF BLEND
SUNDAY INTO EARLY NEXT WEEK.
.TONIGHT THROUGH FRIDAY...ABOVE NORMAL TEMPS STILL THE MAIN
CONCERN DURING THIS PERIOD WITH RETURN FLOW DEVELOPING TONIGHT
AS THE SURFACE HIGH SHIFTS EAST. GOOD WAA AND ENOUGH MIXING WILL
PUT TEMPS NEAR 60 ACROSS THE CENTRAL TO SOUTHWEST THURSDAY. 850MB
TEMPS WARM TO +10-12C BY THURSDAY AFTERNOON...ALTHOUGH MIXING
LOOKS TO BE ONLY UP TO 900MB ACCORDING TO THE NAM/GFS BUFR
SOUNDINGS. THE WAA CONTINUES THROUGH FRIDAY...BUT WITH A DECENT
AMOUNT OF MID-LEVEL THETA-E ADVECTION AND INCREASED MOISTURE
TRANSPORT ALONG THE 295K TO 305K ISENTROPIC SURFACES...CLOUD
COVER MAY PLAY A ROLE IN THE MAX TEMPS. THINKING WITH THE WARM
START FRIDAY MORNING...COMBINED WITH THE SURGE OF SURFACE DEW
POINTS INTO THE 45 TO 55 DEGREE RANGE...FELT CONFIDENT ENOUGH TO
BUMP MAX TEMPS UP A DEGREE ACROSS THE SOUTH AND WEST EVEN WITH THE
CLOUD COVER PRESENT. KEPT ONGOING FORECAST HIGHS FOR THE NORTH
AND EAST.
SOUNDINGS INDICATIVE OF DRIZZLE BY FRIDAY NIGHT ACROSS NORTHERN
IOWA WITH SOME WEAK ISENTROPIC LIFT PRESENT TO WARRANT THE MENTION
OF DRIZZLE IN NORTHERN IOWA. GFS IS A LITTLE QUICKER WITH
SATURATION BELOW 800MB AT MCW/ALO/DSM. SO KEPT WITH SLIGHT POPS
B/T 00-12Z SATURDAY. MODELS STILL DEPICTING SOME ELEVATED
INSTABILITY FRIDAY AFTERNOON INTO THE EVENING AND KEPT MENTION OF
ISOLATED THUNDER IN THE SOUTH-CENTRAL.
.SATURDAY AND SUNDAY...HAVE LINGERING POPS ACROSS THE EAST WITH
WARM FRONT SURGING INTO MN/WI AREA. DECREASED POPS DURING THE
DAY SATURDAY WITH STRONG CAP IN PLACE AND NO TRIGGER UNTIL THE
COLD FRONT ENTERS THE STATE SATURDAY NIGHT. VERY STRONG MIXING AND
WAA THROUGHOUT THE DAY SATURDAY AND LIMITED CLOUD COVER ACROSS THE
SOUTHWEST...TWEAKED MAX TEMPS UP SLIGHTLY. MODELS HAVE BACK OFF
SOME ON THE VERY GUSTY WINDS...BUT STILL EXPECTING A WINDY
AFTERNOON SATURDAY.
FRONT LOOKS TO ENTER THE NORTHWEST PORTION OF THE FORECAST AREA BY
06Z SUNDAY...AND CLEAR THE SOUTHEAST SHORTLY AFTER 18Z SUNDAY.
BEST FORCING AND DEEPEST MOISTURE WILL BE ALONG AND JUST AHEAD
THE FRONT SATURDAY NIGHT INTO SUNDAY MORNING. HAVE KEPT WITH
HIGHEST POPS DURING THIS TIME FRAME. COLUMN LOSES ICE INTRODUCTION
SUNDAY AFTERNOON AND MAY SEE DRIZZLE/FZDZ INTO SUNDAY EVENING WITH
THE STRONG CAA INTO THE STATE. LOW CONFIDENCE WITH MENTION ATTM.
.MONDAY INTO TUESDAY...CAA CONTINUES INTO SUNDAY AND LIKELY WILL
SEE SOME LINGERING STRATUS ACROSS THE NORTH THROUGH MONDAY
AFTERNOON. SOUNDING NOT DEPICTING THIS SCENARIO VERY WELL...BUT
GFS/ECMWF SHOWING SOME MID-LEVEL RH GREATER THAN 80 PERCENT
THROUGH 18Z MONDAY. REGARDLESS...MONDAY HIGH TEMPS MAY NOT GET
ABOVE FREEZING IN NORTHERN IOWA.
&&
.AVIATION...07/06Z
STATUS WILL CONTINUE TO SPREAD ACROSS THE STATE OVERNIGHT INTO
WEDNESDAY MORNING AS UPPER SYSTEM ACRS WI/IL DEPARTS TO THE
SOUTHEAST. THE CEILING WILL REMAIN VFR ON THE BACKSIDE BUT
LOCATIONS FROM KMCW...KALO AND EVEN KOTM WILL SEE MVFR CIGS
OVERNIGHT INTO MID MORNING WEDNESDAY. CEILINGS WILL GRADUALLY LIFT
ON WEDNESDAY AND DISSIPATE FROM WEST TO EAST DURING THE DAY.
WIDESPREAD VFR CONDITIONS ARE EXPECTED BY WEDNESDAY EVENING AS
SURFACE RIDGE SLIDES OVER THE STATE AND TO THE EAST.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...PODRAZIK
AVIATION...COGIL
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
1146 AM CST WED NOV 7 2012
...UPDATED FOR AVIATION...
.SYNOPSIS...
ISSUED AT 354 AM CST WED NOV 7 2012
THE BASIC LONGWAVE CONFIGURATION OF RIDGE IN THE WEST AND TROUGH IN
THE EAST (CONUS) CONTINUES EARLY THIS MORNING, HOWEVER THE RIDGE
AXIS OUT WEST WAS SHIFTING EAST AS ANOTHER DEEP TROUGH FORMED OFF
THE COAST OF BRITISH COLUMBIA AND THE NORTHWEST CONUS. A NOREASTER
WAS UNDERGOING A SIGNIFICANT DEVELOPMENT PROCESS JUST OFF THE NEW
JERSEY/DELAWARE COAST. CLOSER TO HOME, A BROAD 1020MB HIGH EXTENDED
FROM THE DAKOTAS SOUTH THROUGH NEBRASKA/KANSAS INTO MUCH OF TEXAS.
LIGHT IF NOT CALM WINDS WERE FOUND ALL ACROSS THE CENTRAL PLAINS
DURING THE OVERNIGHT HOURS. LEESIDE LOW PRESSURE WAS UNDERGOING
DEVELOPMENT ACROSS MONTANA IN ADVANCE OF A FORMIDABLE PACIFIC JET
CORE WHICH WAS NOSING INTO THE ALBERTA ROCKIES PER RAP ANALYSIS AND
WV LOOP EARLY THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 354 AM CST WED NOV 7 2012
THE MAIN FORECAST CHALLENGE FOR TODAY AND TONIGHT WILL BE
TEMPERATURES. THE REMNANT COOL AIRMASS IN THE WAKE OF THE DEPARTING
UPPER LEVEL TROUGH WILL CERTAINLY HAVE SOME INFLUENCE ON HOW WARM
SOME PORTIONS OF THE SOUTHWEST KANSAS REGION WILL GET. 850MB
TEMPERATURE FORECAST OFF THE MODELS SHOWS QUITE A BIT OF RANGE FROM
+21C AT ELKHART AT 00Z THIS EVENING TO ONLY +11C ALONG A HAYS TO
MEDICINE LODGE LINE. AS LEESIDE TROUGH FURTHER DEEPENS ACROSS
EASTERN COLORADO, WINDS WILL BE ON THE INCREASE, WITH 15 TO 20 KNOTS
COMMON FROM LATE MORNING THROUGH THE AFTERNOON HOURS. WIND DIRECTION
WILL HAVE A SLIGHT EASTERLY UPSLOPE COMPONENT WHICH WILL LIMIT THE
MAXIMUM TEMPERATURE POTENTIAL ACROSS CENTRAL AND SOUTH CENTRAL
KANSAS. AM ONLY LOOKING AT HIGHS IN THE 64 TO 67F RANGE (HAYS TO
MEDICINE LODGE), WITH 77-79F COMMON FOR HIGHS FROM SYRACUSE TO
JOHNSON TO ELKHART CLOSE TO THE COLORADO BORDER.
TONIGHT...THE SURFACE LEE TROUGH WILL NUDGE EASTWARD THROUGH THE
OVERNIGHT HOURS, AND THIS WILL CAUSE SURFACE WINDS TO DECREASE WEST
OF HIGHWAY 83 TO THE COLORADO BORDER. THE MOSTLY CLEAR SKY AND LIGHT
WINDS SHOULD ALLOW TEMPERATURES TO BOTTOM OUT IN THE 32 TO 34F RANGE
ACROSS THE WESTERN THIRD OF THE FORECAST AREA (ROUGHLY ALONG AND
WEST OF A HIGHWAY 83 LINE. FARTHER EAST (ESPECIALLY CENTRAL AND
SOUTH CENTRAL KANSAS), TEMPERATURES ARE EXPECTED TO ONLY BOTTOM OUT
IN THE LOWER 40S WITH MEAN WIND SPEEDS THROUGH THE NIGHT 11 TO 14
KNOTS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 423 AM CST WED NOV 7 2012
THE GREATEST EXCITEMENT FOR THE EXTENDED PERIOD IS THE DEEP UPPER
LEVEL CYCLONE NEAR 140W THAT IS DIGGING TOWARD THE WESTERN UNITED
STATES IN RESPONSE TO RISING HEIGHTS OVER THE ALEUTIANS AND WESTERN
ALASKA IN ADVANCE OF A POWERFUL TROUGH JUST WEST OF THE DATELINE.
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH DETAILS OF THE DEEP
TROUGH AS IT APPROACHES THE CENTRAL PLAINS OVER THE WEEKEND,
ALTHOUGH THE AIR BEHIND THE FRONT IS COLD ENOUGH THAT IT MAY SURGE
SOUTHWARD AS A DENSITY CURRENT FASTER THAN ANY OF THE GUIDANCE AFTER
SUNSET SATURDAY NIGHT. THERE STILL APPEARS TO BE A COHERENT TROPICAL
THUNDERSTORM CLUSTER IN THE EASTERN INDIAN OCEAN PROPAGATING TOWARD
THE MARITIME CONTINENT. THE MODELS STILL ARE STRUGGLING WITH
EVOLUTION OF THE CLUSTER, AND THE ECMWF SOLUTION OF PROPAGATING AT
LEAST A WEAK MJO INTO THE WESTERN PACIFIC BY AROUND 15 NOVEMBER
SEEMS MOST REASONABLE. WITH THE MJO LIKELY TO MOVE INTO PHASE 6 OF
THE WHEELER/HENDON PHASE SPACE DIAGRAM, A BROAD RIDGE IN THE WESTERN
UNITED STATES AND STRONG FLOW ACROSS THE CANADIAN ROCKIES SHOULD
EVOLVE. THIS WILL FAVOR A MILD REGIME ACROSS MUCH OF THE COUNTRY
WITH LITTLE POTENTIAL FOR INVASION OF COLD CANADIAN AIR. PHASE 6
CORRELATES WITH INCREASED MOISTURE CHANCES IN THE MISSISSIPPI
VALLEY, AND THE EVOLUTION OF A SOUTHERN BRANCH UPPER LEVEL TROUGH
OVER THE SOUTHERN PLAINS AROUND 16 NOVEMBER IS VERY REASONABLE.
IN THE SHORTER TERM, A WARM AND DRY PATTERN WILL PREVAIL THROUGH
SATURDAY WITH UPPER LEVEL RIDGING OVER THE CENTRAL PLAINS. THE UPPER
LEVEL TROUGH MOVING THROUGH SOUTHERN BRITISH COLUMBIA THIS MORNING
WILL REACH SOUTHERN MANITOBA BY THURSDAY MORNING, AND IT APPEARS
THAT THE COLD FRONT WITH THIS SYSTEM WILL SURGE FARTHER SOUTH THAN
PLANNED AT THIS TIME YESTERDAY, REACHING NORTHERN KANSAS BY NOON
THURSDAY. A MINOR UPPER LEVEL TROUGH IN THE TROPICAL PACIFIC WEST OF
BAJA CALIFORNIA WILL BE EJECTED AS THE DEEP UPPER LEVEL TROUGH DIGS
INTO THE WESTERN UNITED STATES AND WILL APPROACH KANSAS THURSDAY
NIGHT. CYCLOGENESIS IN SOUTHEAST COLORADO IN ADVANCE OF THE MINOR
TROUGH WILL BACK WINDS IN WESTERN KANSAS THURSDAY AND WRAP SOME OF
THE COOL AIR WITH THE NORTHERN KANSAS FRONT INTO WEST CENTRAL
KANSAS. TEMPERATURES IN THE GRIDS WERE DROPPED A FEW DEGREES IN
NORTHERN AND WEST CENTRAL KANSAS IN RESPONSE TO THE BACKED WINDS AND
WEAK COLD AIR ADVECTION.
HIGH LEVEL CLOUDINESS WILL INCREASE THURSDAY AFTERNOON AND MAY
BECOME FAIRLY THICK THURSDAY NIGHT WITH THE APPROACH OF THE MINOR
UPPER LEVEL TROUGH. BY FRIDAY, THE WEAK FRONT WILL LIFT NORTH AS A
WARM FRONT IN RESPONSE TO FALLING PRESSURES IN WYOMING, AND VERY
WARM AIR WILL SPREAD ACROSS ALL OF SOUTHWEST KANSAS. HIGH LEVEL
CLOUDINESS LIKELY WILL THIN DURING THE DAY, ALLOWING FOR NEARLY FULL
INSOLATION. WIDESPREAD HIGHS IN THE UPPER 70S AND LOWER 80S ARE
LIKELY WITH SOME MID 80S NEAR THE OKLAHOMA BORDER.
BY SATURDAY, MODEST LOW LEVEL MOISTURE RETURN WILL RAISE DEWPOINTS
INTO THE 50S BY AFTERNOON IN SOUTH CENTRAL AND EASTERN KANSAS, BUT
DEWPOINTS WILL REMAIN IN THE 30S ACROSS MUCH OF SOUTHWEST KANSAS.
VERY COLD AIR WILL BEGIN TO PROGRESS INTO NORTHERN KANSAS BY
AFTERNOON AS A MINOR TROUGH ROTATING AROUND THE DEEP UPPER LEVEL
CYCLONE RIPPLES FROM COLORADO TO THE NORTHERN PLAINS. THE COLD AIR
WILL PLUNGE SOUTHWARD AS A DENSITY CURRENT AFTER SUNSET SATURDAY
WITH WINDS LIKELY REACHING ADVISORY CRITERIA FOR A FEW HOURS BEHIND
THE FRONT. ALTHOUGH INSTABILITY IS NOT GREAT, SCATTERED
THUNDERSTORMS MAY FORM SATURDAY EVENING ALONG THE WEST EDGE OF THE
MOIST AXIS IN SOUTH CENTRAL AND CENTRAL KANSAS AND PROPAGATE
EASTWARD DURING THE NIGHT AS THE FRONT SURGES.
TEMPERATURES WILL FALL QUICKLY BEHIND THE FRONT AND LIKELY WILL DROP
BELOW FREEZING BY SUNRISE SUNDAY IN WEST CENTRAL KANSAS. WITH THE
APPROACH OF THE UPPER LEVEL COLD POOL AND UPPER LEVEL DIVERGENCE IN
THE ENTRANCE REGION OF A JET STREAK, SUFFICIENT UPWARD VERTICAL
MOTION WILL BE GENERATED TO SUPPORT CONSIDERABLE MID LEVEL
CLOUDINESS AND SOME SNOW FLURRIES ACROSS MUCH OF SOUTHWEST KANSAS
SUNDAY. STRONG COLD AIR ADVECTION AND SUBSIDENCE IN THE LOWER LEVELS
OF THE ATMOSPHERE ALONG WITH LIMITED MOISTURE MOST LIKELY WILL
PRECLUDE ANY MEASURABLE SNOWFALL. TEMPERATURES SUNDAY WILL BE COLD
AND WILL NOT RISE ABOVE THE 30S IN WEST CENTRAL AND NORTH CENTRAL
KANSAS.
ZONAL UPPER LEVEL FLOW WILL FAVOR LEE TROUGHING AND DOWNSLOPE FLOW
EARLY NEXT WEEK, AND THE COLD AIR WILL MODIFY QUICKLY. THE NEXT
POSSIBILITY OF PRECIPITATION WILL BE 15-16 NOVEMBER WITH THE
APPROACH OF A TROUGH IN THE SOUTHERN BRANCH OF THE WESTERLIES.
DETAILS OF THIS EVENT ARE HIGHLY UNCERTAIN, BUT TEMPERATURES SHOULD
BE WARM ENOUGH TO KEEP ANY PRECIPITATION IN LIQUID FORM.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1128 AM CST WED NOV 7 2012
AN UPPER LEVEL RIDGE WILL MOVE EAST FROM THE WESTERN HIGH PLAINS
AND INTO THE MID MISSISSIPPI VALLEY BY THURSDAY WITH A WEAK
SURFACE TROUGH OF LOW PRESSURE REMAINING IN THE LEE OF THE
ROCKIES. AN 850MB LOW LEVEL JET IS FORECAST FROM THE SOUTHWEST
AT 40 TO 50KT FROM 06-12Z TONIGHT SO SOME AREAS OF LOW LEVEL WIND
SHEAR ARE POSSIBLE. EXPECT VFR CONDITIONS WITH SOUTHEAST WINDS
AROUND 10-15KT BECOMING SOUTH TO SOUTHWESTERLY WITH A WARM FRONT
AFTER 10-12Z. HIGH LEVEL CLOUDINESS WILL INCREASE AFTER 12Z.
&&
.FIRE WEATHER...
ISSUED AT 423 AM CST WED NOV 7 2012
TEMPERATURES WILL APPROACH 80 DEGREES THURSDAY ALONG THE OKLAHOMA
BORDER SOUTH OF A WEAK COLD FRONT. RELATIVE HUMIDITIES WILL DROP TO
INTO THE 15 TO 20 PERCENT RANGE. WITH CURED FUELS, ACTIVE FIRE
BEHAVIOR CAN BE EXPECTED, ALTHOUGH WIND SPEEDS AND RELATIVE HUMIDITY
VALUES WILL BE MARGINAL FOR RED FLAG CONDITIONS. SOUTH TO SOUTHWEST
WINDS WILL INCREASE TO 20 TO 25 MPH WITH HIGHER GUSTS ON FRIDAY, AND
RELATIVE HUMIDITIES WILL DROP INTO THE 15 TO 20 PERCENT RANGE ONCE
AGAIN. A FIRE WEATHER WATCH MAY BE REQUIRED, BUT CONFIDENCE IS NOT
SUFFICIENT TO JUSTIFY ISSUANCE YET. LOW LEVEL MOISTURE WILL INCREASE
EAST OF HIGHWAY 283 ON SATURDAY, BUT LOW RELATIVE HUMIDITIES AND
STRONG WINDS WILL RESULT IN ACTIVE FIRE BEHAVIOR AGAIN SATURDAY
AFTERNOON WEST OF HIGHWAY 283.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 70 41 73 48 / 0 0 0 0
GCK 71 37 73 46 / 0 0 0 0
EHA 78 42 77 48 / 0 0 0 0
LBL 75 38 77 51 / 0 0 0 0
HYS 64 35 67 44 / 0 0 0 0
P28 67 39 75 55 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...RUTHI
AVIATION...KRUSE
FIRE WEATHER...RUTHI
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
610 AM CST WED NOV 7 2012
...UPDATED AVIATION SECTION...
.SYNOPSIS...
ISSUED AT 354 AM CST WED NOV 7 2012
THE BASIC LONGWAVE CONFIGURATION OF RIDGE IN THE WEST AND TROUGH IN
THE EAST (CONUS) CONTINUES EARLY THIS MORNING, HOWEVER THE RIDGE
AXIS OUT WEST WAS SHIFTING EAST AS ANOTHER DEEP TROUGH FORMED OFF
THE COAST OF BRITISH COLUMBIA AND THE NORTHWEST CONUS. A NOREASTER
WAS UNDERGOING A SIGNIFICANT DEVELOPMENT PROCESS JUST OFF THE NEW
JERSEY/DELAWARE COAST. CLOSER TO HOME, A BROAD 1020MB HIGH EXTENDED
FROM THE DAKOTAS SOUTH THROUGH NEBRASKA/KANSAS INTO MUCH OF TEXAS.
LIGHT IF NOT CALM WINDS WERE FOUND ALL ACROSS THE CENTRAL PLAINS
DURING THE OVERNIGHT HOURS. LEESIDE LOW PRESSURE WAS UNDERGOING
DEVELOPMENT ACROSS MONTANA IN ADVANCE OF A FORMIDABLE PACIFIC JET
CORE WHICH WAS NOSING INTO THE ALBERTA ROCKIES PER RAP ANALYSIS AND
WV LOOP EARLY THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 354 AM CST WED NOV 7 2012
THE MAIN FORECAST CHALLENGE FOR TODAY AND TONIGHT WILL BE
TEMPERATURES. THE REMNANT COOL AIRMASS IN THE WAKE OF THE DEPARTING
UPPER LEVEL TROUGH WILL CERTAINLY HAVE SOME INFLUENCE ON HOW WARM
SOME PORTIONS OF THE SOUTHWEST KANSAS REGION WILL GET. 850MB
TEMPERATURE FORECAST OFF THE MODELS SHOWS QUITE A BIT OF RANGE FROM
+21C AT ELKHART AT 00Z THIS EVENING TO ONLY +11C ALONG A HAYS TO
MEDICINE LODGE LINE. AS LEESIDE TROUGH FURTHER DEEPENS ACROSS
EASTERN COLORADO, WINDS WILL BE ON THE INCREASE, WITH 15 TO 20 KNOTS
COMMON FROM LATE MORNING THROUGH THE AFTERNOON HOURS. WIND DIRECTION
WILL HAVE A SLIGHT EASTERLY UPSLOPE COMPONENT WHICH WILL LIMIT THE
MAXIMUM TEMPERATURE POTENTIAL ACROSS CENTRAL AND SOUTH CENTRAL
KANSAS. AM ONLY LOOKING AT HIGHS IN THE 64 TO 67F RANGE (HAYS TO
MEDICINE LODGE), WITH 77-79F COMMON FOR HIGHS FROM SYRACUSE TO
JOHNSON TO ELKHART CLOSE TO THE COLORADO BORDER.
TONIGHT...THE SURFACE LEE TROUGH WILL NUDGE EASTWARD THROUGH THE
OVERNIGHT HOURS, AND THIS WILL CAUSE SURFACE WINDS TO DECREASE WEST
OF HIGHWAY 83 TO THE COLORADO BORDER. THE MOSTLY CLEAR SKY AND LIGHT
WINDS SHOULD ALLOW TEMPERATURES TO BOTTOM OUT IN THE 32 TO 34F RANGE
ACROSS THE WESTERN THIRD OF THE FORECAST AREA (ROUGHLY ALONG AND
WEST OF A HIGHWAY 83 LINE. FARTHER EAST (ESPECIALLY CENTRAL AND
SOUTH CENTRAL KANSAS), TEMPERATURES ARE EXPECTED TO ONLY BOTTOM OUT
IN THE LOWER 40S WITH MEAN WIND SPEEDS THROUGH THE NIGHT 11 TO 14
KNOTS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 423 AM CST WED NOV 7 2012
THE GREATEST EXCITEMENT FOR THE EXTENDED PERIOD IS THE DEEP UPPER
LEVEL CYCLONE NEAR 140W THAT IS DIGGING TOWARD THE WESTERN UNITED
STATES IN RESPONSE TO RISING HEIGHTS OVER THE ALEUTIANS AND WESTERN
ALASKA IN ADVANCE OF A POWERFUL TROUGH JUST WEST OF THE DATELINE.
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH DETAILS OF THE DEEP
TROUGH AS IT APPROACHES THE CENTRAL PLAINS OVER THE WEEKEND,
ALTHOUGH THE AIR BEHIND THE FRONT IS COLD ENOUGH THAT IT MAY SURGE
SOUTHWARD AS A DENSITY CURRENT FASTER THAN ANY OF THE GUIDANCE AFTER
SUNSET SATURDAY NIGHT. THERE STILL APPEARS TO BE A COHERENT TROPICAL
THUNDERSTORM CLUSTER IN THE EASTERN INDIAN OCEAN PROPAGATING TOWARD
THE MARITIME CONTINENT. THE MODELS STILL ARE STRUGGLING WITH
EVOLUTION OF THE CLUSTER, AND THE ECMWF SOLUTION OF PROPAGATING AT
LEAST A WEAK MJO INTO THE WESTERN PACIFIC BY AROUND 15 NOVEMBER
SEEMS MOST REASONABLE. WITH THE MJO LIKELY TO MOVE INTO PHASE 6 OF
THE WHEELER/HENDON PHASE SPACE DIAGRAM, A BROAD RIDGE IN THE WESTERN
UNITED STATES AND STRONG FLOW ACROSS THE CANADIAN ROCKIES SHOULD
EVOLVE. THIS WILL FAVOR A MILD REGIME ACROSS MUCH OF THE COUNTRY
WITH LITTLE POTENTIAL FOR INVASION OF COLD CANADIAN AIR. PHASE 6
CORRELATES WITH INCREASED MOISTURE CHANCES IN THE MISSISSIPPI
VALLEY, AND THE EVOLUTION OF A SOUTHERN BRANCH UPPER LEVEL TROUGH
OVER THE SOUTHERN PLAINS AROUND 16 NOVEMBER IS VERY REASONABLE.
IN THE SHORTER TERM, A WARM AND DRY PATTERN WILL PREVAIL THROUGH
SATURDAY WITH UPPER LEVEL RIDGING OVER THE CENTRAL PLAINS. THE UPPER
LEVEL TROUGH MOVING THROUGH SOUTHERN BRITISH COLUMBIA THIS MORNING
WILL REACH SOUTHERN MANITOBA BY THURSDAY MORNING, AND IT APPEARS
THAT THE COLD FRONT WITH THIS SYSTEM WILL SURGE FARTHER SOUTH THAN
PLANNED AT THIS TIME YESTERDAY, REACHING NORTHERN KANSAS BY NOON
THURSDAY. A MINOR UPPER LEVEL TROUGH IN THE TROPICAL PACIFIC WEST OF
BAJA CALIFORNIA WILL BE EJECTED AS THE DEEP UPPER LEVEL TROUGH DIGS
INTO THE WESTERN UNITED STATES AND WILL APPROACH KANSAS THURSDAY
NIGHT. CYCLOGENESIS IN SOUTHEAST COLORADO IN ADVANCE OF THE MINOR
TROUGH WILL BACK WINDS IN WESTERN KANSAS THURSDAY AND WRAP SOME OF
THE COOL AIR WITH THE NORTHERN KANSAS FRONT INTO WEST CENTRAL
KANSAS. TEMPERATURES IN THE GRIDS WERE DROPPED A FEW DEGREES IN
NORTHERN AND WEST CENTRAL KANSAS IN RESPONSE TO THE BACKED WINDS AND
WEAK COLD AIR ADVECTION.
HIGH LEVEL CLOUDINESS WILL INCREASE THURSDAY AFTERNOON AND MAY
BECOME FAIRLY THICK THURSDAY NIGHT WITH THE APPROACH OF THE MINOR
UPPER LEVEL TROUGH. BY FRIDAY, THE WEAK FRONT WILL LIFT NORTH AS A
WARM FRONT IN RESPONSE TO FALLING PRESSURES IN WYOMING, AND VERY
WARM AIR WILL SPREAD ACROSS ALL OF SOUTHWEST KANSAS. HIGH LEVEL
CLOUDINESS LIKELY WILL THIN DURING THE DAY, ALLOWING FOR NEARLY FULL
INSOLATION. WIDESPREAD HIGHS IN THE UPPER 70S AND LOWER 80S ARE
LIKELY WITH SOME MID 80S NEAR THE OKLAHOMA BORDER.
BY SATURDAY, MODEST LOW LEVEL MOISTURE RETURN WILL RAISE DEWPOINTS
INTO THE 50S BY AFTERNOON IN SOUTH CENTRAL AND EASTERN KANSAS, BUT
DEWPOINTS WILL REMAIN IN THE 30S ACROSS MUCH OF SOUTHWEST KANSAS.
VERY COLD AIR WILL BEGIN TO PROGRESS INTO NORTHERN KANSAS BY
AFTERNOON AS A MINOR TROUGH ROTATING AROUND THE DEEP UPPER LEVEL
CYCLONE RIPPLES FROM COLORADO TO THE NORTHERN PLAINS. THE COLD AIR
WILL PLUNGE SOUTHWARD AS A DENSITY CURRENT AFTER SUNSET SATURDAY
WITH WINDS LIKELY REACHING ADVISORY CRITERIA FOR A FEW HOURS BEHIND
THE FRONT. ALTHOUGH INSTABILITY IS NOT GREAT, SCATTERED
THUNDERSTORMS MAY FORM SATURDAY EVENING ALONG THE WEST EDGE OF THE
MOIST AXIS IN SOUTH CENTRAL AND CENTRAL KANSAS AND PROPAGATE
EASTWARD DURING THE NIGHT AS THE FRONT SURGES.
TEMPERATURES WILL FALL QUICKLY BEHIND THE FRONT AND LIKELY WILL DROP
BELOW FREEZING BY SUNRISE SUNDAY IN WEST CENTRAL KANSAS. WITH THE
APPROACH OF THE UPPER LEVEL COLD POOL AND UPPER LEVEL DIVERGENCE IN
THE ENTRANCE REGION OF A JET STREAK, SUFFICIENT UPWARD VERTICAL
MOTION WILL BE GENERATED TO SUPPORT CONSIDERABLE MID LEVEL
CLOUDINESS AND SOME SNOW FLURRIES ACROSS MUCH OF SOUTHWEST KANSAS
SUNDAY. STRONG COLD AIR ADVECTION AND SUBSIDENCE IN THE LOWER LEVELS
OF THE ATMOSPHERE ALONG WITH LIMITED MOISTURE MOST LIKELY WILL
PRECLUDE ANY MEASURABLE SNOWFALL. TEMPERATURES SUNDAY WILL BE COLD
AND WILL NOT RISE ABOVE THE 30S IN WEST CENTRAL AND NORTH CENTRAL
KANSAS.
ZONAL UPPER LEVEL FLOW WILL FAVOR LEE TROUGHING AND DOWNSLOPE FLOW
EARLY NEXT WEEK, AND THE COLD AIR WILL MODIFY QUICKLY. THE NEXT
POSSIBILITY OF PRECIPITATION WILL BE 15-16 NOVEMBER WITH THE
APPROACH OF A TROUGH IN THE SOUTHERN BRANCH OF THE WESTERLIES.
DETAILS OF THIS EVENT ARE HIGHLY UNCERTAIN, BUT TEMPERATURES SHOULD
BE WARM ENOUGH TO KEEP ANY PRECIPITATION IN LIQUID FORM.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 608 AM CST WED NOV 7 2012
VFR CONDITIONS WILL CONTINUE THROUGH THURSDAY MORNING WITH ONLY A
FEW THIN CIRRUS CLOUDS AOA 250 IN THE HYS VICINITY. AN UPPER LEVEL
RIDGE WILL PERSIST OVER THE CENTRAL PLAINS TODAY, AND A DEEP UPPER
LEVEL TROUGH WILL DIG INTO THE WESTERN UNITED STATES THURSDAY. AT
THE SURFACE, A TROUGH OF LOW PRESSURE WILL DEEPEN IN THE LEE OF THE
ROCKIES TODAY, RESULTING IN A RETURN TO LOW LEVEL SOUTH FLOW AROUND
15 KNOTS BY LATE MORNING.
&&
.FIRE WEATHER...
ISSUED AT 423 AM CST WED NOV 7 2012
TEMPERATURES WILL APPROACH 80 DEGREES THURSDAY ALONG THE OKLAHOMA
BORDER SOUTH OF A WEAK COLD FRONT. RELATIVE HUMIDITIES WILL DROP TO
INTO THE 15 TO 20 PERCENT RANGE. WITH CURED FUELS, ACTIVE FIRE
BEHAVIOR CAN BE EXPECTED, ALTHOUGH WIND SPEEDS AND RELATIVE HUMIDITY
VALUES WILL BE MARGINAL FOR RED FLAG CONDITIONS. SOUTH TO SOUTHWEST
WINDS WILL INCREASE TO 20 TO 25 MPH WITH HIGHER GUSTS ON FRIDAY, AND
RELATIVE HUMIDITIES WILL DROP INTO THE 15 TO 20 PERCENT RANGE ONCE
AGAIN. A FIRE WEATHER WATCH MAY BE REQUIRED, BUT CONFIDENCE IS NOT
SUFFICIENT TO JUSTIFY ISSUANCE YET. LOW LEVEL MOISTURE WILL INCREASE
EAST OF HIGHWAY 283 ON SATURDAY, BUT LOW RELATIVE HUMIDITIES AND
STRONG WINDS WILL RESULT IN ACTIVE FIRE BEHAVIOR AGAIN SATURDAY
AFTERNOON WEST OF HIGHWAY 283.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 70 41 74 48 / 0 0 0 0
GCK 71 36 72 46 / 0 0 0 0
EHA 78 38 79 48 / 0 0 0 0
LBL 75 35 80 51 / 0 0 0 0
HYS 64 39 66 44 / 0 0 0 0
P28 67 42 78 55 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...RUTHI
AVIATION...RUTHI
FIRE WEATHER...RUTHI
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
426 AM CST WED NOV 7 2012
...UPDATED LONG TERM AND FIRE WEATHER SECTIONS...
.SYNOPSIS...
ISSUED AT 354 AM CST WED NOV 7 2012
THE BASIC LONGWAVE CONFIGURATION OF RIDGE IN THE WEST AND TROUGH IN
THE EAST (CONUS) CONTINUES EARLY THIS MORNING, HOWEVER THE RIDGE
AXIS OUT WEST WAS SHIFTING EAST AS ANOTHER DEEP TROUGH FORMED OFF
THE COAST OF BRITISH COLUMBIA AND THE NORTHWEST CONUS. A NOREASTER
WAS UNDERGOING A SIGNIFICANT DEVELOPMENT PROCESS JUST OFF THE NEW
JERSEY/DELAWARE COAST. CLOSER TO HOME, A BROAD 1020MB HIGH EXTENDED
FROM THE DAKOTAS SOUTH THROUGH NEBRASKA/KANSAS INTO MUCH OF TEXAS.
LIGHT IF NOT CALM WINDS WERE FOUND ALL ACROSS THE CENTRAL PLAINS
DURING THE OVERNIGHT HOURS. LEESIDE LOW PRESSURE WAS UNDERGOING
DEVELOPMENT ACROSS MONTANA IN ADVANCE OF A FORMIDABLE PACIFIC JET
CORE WHICH WAS NOSING INTO THE ALBERTA ROCKIES PER RAP ANALYSIS AND
WV LOOP EARLY THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 354 AM CST WED NOV 7 2012
THE MAIN FORECAST CHALLENGE FOR TODAY AND TONIGHT WILL BE
TEMPERATURES. THE REMNANT COOL AIRMASS IN THE WAKE OF THE DEPARTING
UPPER LEVEL TROUGH WILL CERTAINLY HAVE SOME INFLUENCE ON HOW WARM
SOME PORTIONS OF THE SOUTHWEST KANSAS REGION WILL GET. 850MB
TEMPERATURE FORECAST OFF THE MODELS SHOWS QUITE A BIT OF RANGE FROM
+21C AT ELKHART AT 00Z THIS EVENING TO ONLY +11C ALONG A HAYS TO
MEDICINE LODGE LINE. AS LEESIDE TROUGH FURTHER DEEPENS ACROSS
EASTERN COLORADO, WINDS WILL BE ON THE INCREASE, WITH 15 TO 20 KNOTS
COMMON FROM LATE MORNING THROUGH THE AFTERNOON HOURS. WIND DIRECTION
WILL HAVE A SLIGHT EASTERLY UPSLOPE COMPONENT WHICH WILL LIMIT THE
MAXIMUM TEMPERATURE POTENTIAL ACROSS CENTRAL AND SOUTH CENTRAL
KANSAS. AM ONLY LOOKING AT HIGHS IN THE 64 TO 67F RANGE (HAYS TO
MEDICINE LODGE), WITH 77-79F COMMON FOR HIGHS FROM SYRACUSE TO
JOHNSON TO ELKHART CLOSE TO THE COLORADO BORDER.
TONIGHT...THE SURFACE LEE TROUGH WILL NUDGE EASTWARD THROUGH THE
OVERNIGHT HOURS, AND THIS WILL CAUSE SURFACE WINDS TO DECREASE WEST
OF HIGHWAY 83 TO THE COLORADO BORDER. THE MOSTLY CLEAR SKY AND LIGHT
WINDS SHOULD ALLOW TEMPERATURES TO BOTTOM OUT IN THE 32 TO 34F RANGE
ACROSS THE WESTERN THIRD OF THE FORECAST AREA (ROUGHLY ALONG AND
WEST OF A HIGHWAY 83 LINE. FARTHER EAST (ESPECIALLY CENTRAL AND
SOUTH CENTRAL KANSAS), TEMPERATURES ARE EXPECTED TO ONLY BOTTOM OUT
IN THE LOWER 40S WITH MEAN WIND SPEEDS THROUGH THE NIGHT 11 TO 14
KNOTS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 423 AM CST WED NOV 7 2012
THE GREATEST EXCITEMENT FOR THE EXTENDED PERIOD IS THE DEEP UPPER
LEVEL CYCLONE NEAR 140W THAT IS DIGGING TOWARD THE WESTERN UNITED
STATES IN RESPONSE TO RISING HEIGHTS OVER THE ALEUTIANS AND WESTERN
ALASKA IN ADVANCE OF A POWERFUL TROUGH JUST WEST OF THE DATELINE.
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH DETAILS OF THE DEEP
TROUGH AS IT APPROACHES THE CENTRAL PLAINS OVER THE WEEKEND,
ALTHOUGH THE AIR BEHIND THE FRONT IS COLD ENOUGH THAT IT MAY SURGE
SOUTHWARD AS A DENSITY CURRENT FASTER THAN ANY OF THE GUIDANCE AFTER
SUNSET SATURDAY NIGHT. THERE STILL APPEARS TO BE A COHERENT TROPICAL
THUNDERSTORM CLUSTER IN THE EASTERN INDIAN OCEAN PROPAGATING TOWARD
THE MARITIME CONTINENT. THE MODELS STILL ARE STRUGGLING WITH
EVOLUTION OF THE CLUSTER, AND THE ECMWF SOLUTION OF PROPAGATING AT
LEAST A WEAK MJO INTO THE WESTERN PACIFIC BY AROUND 15 NOVEMBER
SEEMS MOST REASONABLE. WITH THE MJO LIKELY TO MOVE INTO PHASE 6 OF
THE WHEELER/HENDON PHASE SPACE DIAGRAM, A BROAD RIDGE IN THE WESTERN
UNITED STATES AND STRONG FLOW ACROSS THE CANADIAN ROCKIES SHOULD
EVOLVE. THIS WILL FAVOR A MILD REGIME ACROSS MUCH OF THE COUNTRY
WITH LITTLE POTENTIAL FOR INVASION OF COLD CANADIAN AIR. PHASE 6
CORRELATES WITH INCREASED MOISTURE CHANCES IN THE MISSISSIPPI
VALLEY, AND THE EVOLUTION OF A SOUTHERN BRANCH UPPER LEVEL TROUGH
OVER THE SOUTHERN PLAINS AROUND 16 NOVEMBER IS VERY REASONABLE.
IN THE SHORTER TERM, A WARM AND DRY PATTERN WILL PREVAIL THROUGH
SATURDAY WITH UPPER LEVEL RIDGING OVER THE CENTRAL PLAINS. THE UPPER
LEVEL TROUGH MOVING THROUGH SOUTHERN BRITISH COLUMBIA THIS MORNING
WILL REACH SOUTHERN MANITOBA BY THURSDAY MORNING, AND IT APPEARS
THAT THE COLD FRONT WITH THIS SYSTEM WILL SURGE FARTHER SOUTH THAN
PLANNED AT THIS TIME YESTERDAY, REACHING NORTHERN KANSAS BY NOON
THURSDAY. A MINOR UPPER LEVEL TROUGH IN THE TROPICAL PACIFIC WEST OF
BAJA CALIFORNIA WILL BE EJECTED AS THE DEEP UPPER LEVEL TROUGH DIGS
INTO THE WESTERN UNITED STATES AND WILL APPROACH KANSAS THURSDAY
NIGHT. CYCLOGENESIS IN SOUTHEAST COLORADO IN ADVANCE OF THE MINOR
TROUGH WILL BACK WINDS IN WESTERN KANSAS THURSDAY AND WRAP SOME OF
THE COOL AIR WITH THE NORTHERN KANSAS FRONT INTO WEST CENTRAL
KANSAS. TEMPERATURES IN THE GRIDS WERE DROPPED A FEW DEGREES IN
NORTHERN AND WEST CENTRAL KANSAS IN RESPONSE TO THE BACKED WINDS AND
WEAK COLD AIR ADVECTION.
HIGH LEVEL CLOUDINESS WILL INCREASE THURSDAY AFTERNOON AND MAY
BECOME FAIRLY THICK THURSDAY NIGHT WITH THE APPROACH OF THE MINOR
UPPER LEVEL TROUGH. BY FRIDAY, THE WEAK FRONT WILL LIFT NORTH AS A
WARM FRONT IN RESPONSE TO FALLING PRESSURES IN WYOMING, AND VERY
WARM AIR WILL SPREAD ACROSS ALL OF SOUTHWEST KANSAS. HIGH LEVEL
CLOUDINESS LIKELY WILL THIN DURING THE DAY, ALLOWING FOR NEARLY FULL
INSOLATION. WIDESPREAD HIGHS IN THE UPPER 70S AND LOWER 80S ARE
LIKELY WITH SOME MID 80S NEAR THE OKLAHOMA BORDER.
BY SATURDAY, MODEST LOW LEVEL MOISTURE RETURN WILL RAISE DEWPOINTS
INTO THE 50S BY AFTERNOON IN SOUTH CENTRAL AND EASTERN KANSAS, BUT
DEWPOINTS WILL REMAIN IN THE 30S ACROSS MUCH OF SOUTHWEST KANSAS.
VERY COLD AIR WILL BEGIN TO PROGRESS INTO NORTHERN KANSAS BY
AFTERNOON AS A MINOR TROUGH ROTATING AROUND THE DEEP UPPER LEVEL
CYCLONE RIPPLES FROM COLORADO TO THE NORTHERN PLAINS. THE COLD AIR
WILL PLUNGE SOUTHWARD AS A DENSITY CURRENT AFTER SUNSET SATURDAY
WITH WINDS LIKELY REACHING ADVISORY CRITERIA FOR A FEW HOURS BEHIND
THE FRONT. ALTHOUGH INSTABILITY IS NOT GREAT, SCATTERED
THUNDERSTORMS MAY FORM SATURDAY EVENING ALONG THE WEST EDGE OF THE
MOIST AXIS IN SOUTH CENTRAL AND CENTRAL KANSAS AND PROPAGATE
EASTWARD DURING THE NIGHT AS THE FRONT SURGES.
TEMPERATURES WILL FALL QUICKLY BEHIND THE FRONT AND LIKELY WILL DROP
BELOW FREEZING BY SUNRISE SUNDAY IN WEST CENTRAL KANSAS. WITH THE
APPROACH OF THE UPPER LEVEL COLD POOL AND UPPER LEVEL DIVERGENCE IN
THE ENTRANCE REGION OF A JET STREAK, SUFFICIENT UPWARD VERTICAL
MOTION WILL BE GENERATED TO SUPPORT CONSIDERABLE MID LEVEL
CLOUDINESS AND SOME SNOW FLURRIES ACROSS MUCH OF SOUTHWEST KANSAS
SUNDAY. STRONG COLD AIR ADVECTION AND SUBSIDENCE IN THE LOWER LEVELS
OF THE ATMOSPHERE ALONG WITH LIMITED MOISTURE MOST LIKELY WILL
PRECLUDE ANY MEASURABLE SNOWFALL. TEMPERATURES SUNDAY WILL BE COLD
AND WILL NOT RISE ABOVE THE 30S IN WEST CENTRAL AND NORTH CENTRAL
KANSAS.
ZONAL UPPER LEVEL FLOW WILL FAVOR LEE TROUGHING AND DOWNSLOPE FLOW
EARLY NEXT WEEK, AND THE COLD AIR WILL MODIFY QUICKLY. THE NEXT
POSSIBILITY OF PRECIPITATION WILL BE 15-16 NOVEMBER WITH THE
APPROACH OF A TROUGH IN THE SOUTHERN BRANCH OF THE WESTERLIES.
DETAILS OF THIS EVENT ARE HIGHLY UNCERTAIN, BUT TEMPERATURES SHOULD
BE WARM ENOUGH TO KEEP ANY PRECIPITATION IN LIQUID FORM.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1142 PM CST TUE NOV 6 2012
LIGHT WINDS TONIGHT WILL BECOME SOUTH TO SOUTHEAST DURING THE MID
MORNING HOURS WITH SPEEDS INCREASING TO 12 TO 15 KNOTS, ESPECIALLY
IN THE AFTERNOON HOURS AS A LEE TROUGH DEEPENS UP AND DOWN THE
HIGH PLAINS FROM EASTERN MONTANA TO EASTERN COLORADO.
&&
.FIRE WEATHER...
ISSUED AT 423 AM CST WED NOV 7 2012
TEMPERATURES WILL APPROACH 80 DEGREES THURSDAY ALONG THE OKLAHOMA
BORDER SOUTH OF A WEAK COLD FRONT. RELATIVE HUMIDITIES WILL DROP TO
INTO THE 15 TO 20 PERCENT RANGE. WITH CURED FUELS, ACTIVE FIRE
BEHAVIOR CAN BE EXPECTED, ALTHOUGH WIND SPEEDS AND RELATIVE HUMIDITY
VALUES WILL BE MARGINAL FOR RED FLAG CONDITIONS. SOUTH TO SOUTHWEST
WINDS WILL INCREASE TO 20 TO 25 MPH WITH HIGHER GUSTS ON FRIDAY, AND
RELATIVE HUMIDITIES WILL DROP INTO THE 15 TO 20 PERCENT RANGE ONCE
AGAIN. A FIRE WEATHER WATCH MAY BE REQUIRED, BUT CONFIDENCE IS NOT
SUFFICIENT TO JUSTIFY ISSUANCE YET. LOW LEVEL MOISTURE WILL INCREASE
EAST OF HIGHWAY 283 ON SATURDAY, BUT LOW RELATIVE HUMIDITIES AND
STRONG WINDS WILL RESULT IN ACTIVE FIRE BEHAVIOR AGAIN SATURDAY
AFTERNOON WEST OF HIGHWAY 283.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 70 41 74 48 / 0 0 0 0
GCK 71 36 72 46 / 0 0 0 0
EHA 78 38 78 48 / 0 0 0 0
LBL 75 35 77 51 / 0 0 0 0
HYS 64 39 66 44 / 0 0 0 0
P28 67 42 79 55 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...RUTHI
AVIATION...UMSCHEID
FIRE WEATHER...RUTHI
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
355 AM CST WED NOV 7 2012
...UPDATED SYNOPSIS AND SHORT TERM SECTIONS...
.SYNOPSIS...
ISSUED AT 354 AM CST WED NOV 7 2012
THE BASIC LONGWAVE CONFIGURATION OF RIDGE IN THE WEST AND TROUGH IN
THE EAST (CONUS) CONTINUES EARLY THIS MORNING, HOWEVER THE RIDGE
AXIS OUT WEST WAS SHIFTING EAST AS ANOTHER DEEP TROUGH FORMED OFF
THE COAST OF BRITISH COLUMBIA AND THE NORTHWEST CONUS. A NOREASTER
WAS UNDERGOING A SIGNIFICANT DEVELOPMENT PROCESS JUST OFF THE NEW
JERSEY/DELAWARE COAST. CLOSER TO HOME, A BROAD 1020MB HIGH EXTENDED
FROM THE DAKOTAS SOUTH THROUGH NEBRASKA/KANSAS INTO MUCH OF TEXAS.
LIGHT IF NOT CALM WINDS WERE FOUND ALL ACROSS THE CENTRAL PLAINS
DURING THE OVERNIGHT HOURS. LEESIDE LOW PRESSURE WAS UNDERGOING
DEVELOPMENT ACROSS MONTANA IN ADVANCE OF A FORMIDABLE PACIFIC JET
CORE WHICH WAS NOSING INTO THE ALBERTA ROCKIES PER RAP ANALYSIS AND
WV LOOP EARLY THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 354 AM CST WED NOV 7 2012
THE MAIN FORECAST CHALLENGE FOR TODAY AND TONIGHT WILL BE
TEMPERATURES. THE REMNANT COOL AIRMASS IN THE WAKE OF THE DEPARTING
UPPER LEVEL TROUGH WILL CERTAINLY HAVE SOME INFLUENCE ON HOW WARM
SOME PORTIONS OF THE SOUTHWEST KANSAS REGION WILL GET. 850MB
TEMPERATURE FORECAST OFF THE MODELS SHOWS QUITE A BIT OF RANGE FROM
+21C AT ELKHART AT 00Z THIS EVENING TO ONLY +11C ALONG A HAYS TO
MEDICINE LODGE LINE. AS LEESIDE TROUGH FURTHER DEEPENS ACROSS
EASTERN COLORADO, WINDS WILL BE ON THE INCREASE, WITH 15 TO 20 KNOTS
COMMON FROM LATE MORNING THROUGH THE AFTERNOON HOURS. WIND DIRECTION
WILL HAVE A SLIGHT EASTERLY UPSLOPE COMPONENT WHICH WILL LIMIT THE
MAXIMUM TEMPERATURE POTENTIAL ACROSS CENTRAL AND SOUTH CENTRAL
KANSAS. AM ONLY LOOKING AT HIGHS IN THE 64 TO 67F RANGE (HAYS TO
MEDICINE LODGE), WITH 77-79F COMMON FOR HIGHS FROM SYRACUSE TO
JOHNSON TO ELKHART CLOSE TO THE COLORADO BORDER.
TONIGHT...THE SURFACE LEE TROUGH WILL NUDGE EASTWARD THROUGH THE
OVERNIGHT HOURS, AND THIS WILL CAUSE SURFACE WINDS TO DECREASE WEST
OF HIGHWAY 83 TO THE COLORADO BORDER. THE MOSTLY CLEAR SKY AND LIGHT
WINDS SHOULD ALLOW TEMPERATURES TO BOTTOM OUT IN THE 32 TO 34F RANGE
ACROSS THE WESTERN THIRD OF THE FORECAST AREA (ROUGHLY ALONG AND
WEST OF A HIGHWAY 83 LINE. FARTHER EAST (ESPECIALLY CENTRAL AND
SOUTH CENTRAL KANSAS), TEMPERATURES ARE EXPECTED TO ONLY BOTTOM OUT
IN THE LOWER 40S WITH MEAN WIND SPEEDS THROUGH THE NIGHT 11 TO 14
KNOTS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 PM CST TUE NOV 6 2012
ON THURSDAY A WARM AIRMASS WILL BE MOVING INTO THE PLAINS AND
WESTERN KANSAS AS UPPER LEVEL RIDGING PUSHES ACROSS THE CENTRAL
CONUS. 850 MB TEMPS RISE FROM AROUND 12C TO AROUND 16C ON THURSDAY
AFTERNOON. AN UPPER LEVEL SUBTROPICAL SHORTWAVE TROUGH WILL ALSO
MOVE NORTHEASTWARD FROM THE DESERT SOUTHWEST ACROSS THE CENTRAL
PLAINS WITH THE MODELS SHOWING INCREASING HIGH LEVEL MOISTURE. IF
THE CIRRUS IS THICK ENOUGH IT COULD HOLD DOWN HIGHS A BIT FOR
THURSDAY.
A STRONG UPPER CLOSED LOW WILL THEN MOVE FROM THE PACIFIC NORTHWEST
ON THURSDAY AND INTO THE WESTERN CONUS AND ROCKIES INTO SATURDAY
WITH A WARM AIRMASS CONTINUING AHEAD OF IT INTO THE PLAINS. AS THE
UPPER SYSTEM PUSHES EAST ON SATURDAY NIGHT INTO SUNDAY, A FEW
THUNDERSTORMS MAY DEVELOP IN PARTS OF SOUTH CENTRAL KANSAS ALONG A
SURFACE DRYLINE BY LATE AFTERNOON SATURDAY, AND INTO THE OVERNIGHT
HOURS AS A STRONG COLD FRONT ADVANCES ACROSS WESTERN KANSAS AFTER
MIDNIGHT. A FEW LIGHT RAIN OR LIGHT SNOW SHOWERS ARE ALSO POSSIBLE
AFTER MIDNIGHT AS A COLD AIRMASS DROPS TEMPERATURES INTO THE MID 30S
BEHIND THE FRONT MAINLY WEST OF HIGHWAY 183. NO SNOW ACCUMULATIONS
ARE ANTICIPATED. SOME LIGHT RAIN OR LIGHT SNOW MAY LINGER INTO
SUNDAY MORNING IN PARTS OF SOUTH CENTRAL KANSAS. THE UPPER LEVEL
TROUGH WILL CONTINUE TO MOVE EAST FROM THE PLAINS SUNDAY AND INTO
THE MISSISSIPPI VALLEY ON MONDAY WITH COLD HIGH PRESSURE IN ITS
WAKE. ON TUESDAY, WEAK UPPER LEVEL RIDGING MOVES BACK INTO THE
PLAINS, WITH SURFACE LEE TROUGHING AND SOUTHERLY WINDS ON THE
BACKSIDE OF A LARGE SURFACE HIGH, EXTENDING FROM THE MID MISSISSIPPI
VALLEY ALL THE WAY TO THE WESTERN GULF OF MEXICO.
EXPECT OVERNIGHT LOWS ON THURSDAY MORNING TO BE AROUND 40 DEGREES,
THEN RISE INTO THE MILD 40S AND 50S INTO SATURDAY MORNING, AHEAD OF
A COLD FRONT. OVERNIGHT LOWS WILL THEN FALL INTO THE 30S BEHIND THE
COLD FRONT ON SUNDAY MORNING AND ONLY IN THE 20S ON MONDAY MORNING.
BY TUESDAY MORNING LOWS WILL MODERATE A BIT BACK INTO THE UPPER 20S
TO LOWER 30S.
DAYTIME HIGHS WILL BE VERY MILD ON THURSDAY AND RANGE FROM AROUND 70
AT HAYS TO AROUND 80 AT ELKHART AND LIBERAL. HIGHS THEN WARM TO NEAR
80 ACROSS ALL OF WESTERN KANSAS ON FRIDAY, AND IN THE LOW TO MID 70S
ON SATURDAY AHEAD OF THE COLD FRONT. ON SUNDAY, HIGHS WILL COOL INTO
THE 40S, WITH HIGHS THEN WARMING BACK INTO THE 50 TO 55 DEGREE RANGE
ON MONDAY AND TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1142 PM CST TUE NOV 6 2012
LIGHT WINDS TONIGHT WILL BECOME SOUTH TO SOUTHEAST DURING THE MID
MORNING HOURS WITH SPEEDS INCREASING TO 12 TO 15 KNOTS, ESPECAILLY
IN THE AFTERNOON HOURS AS A LEE TROUGH DEEPENS UP AND DOWN THE
HIGH PLAINS FROM EASTERN MONTANA TO EASTERN COLORADO.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 70 41 74 48 / 0 0 0 0
GCK 71 36 72 46 / 0 0 0 0
EHA 78 38 78 48 / 0 0 0 0
LBL 75 35 77 51 / 0 0 0 0
HYS 64 39 66 44 / 0 0 0 0
P28 67 42 79 55 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...KRUSE
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
256 PM EST WED NOV 7 2012
.SYNOPSIS...
STRONG LOW PRESSURE WELL EAST OF THE DELAWARE COAST...WILL MOVE
SLOWLY NORTH NORTHEAST THIS AFTERNOON INTO TONIGHT. HIGH PRESSURE
THEN BUILDS OVER THE AREA FOR LATER THURSDAY THROUGH THE UPCOMING
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
STRONG LO PRES WELL E OF THE DE CST...WILL MOVE SLOWLY NNE THIS
AFTN THRU TNGT. ADJUSTED POPS AND WORDING OVR THE REGION INTO THIS
EVENG...BASED ON LATEST SAT PIX AND RUC PARAMETERS. WILL HAVE
LIKELY POPS OVR THE LWR MD AND VA ERN SHR...AND POSSIBLY INTO THE
VA NRN NECK...DUE TO BEST CHC FOR SIGNIFICANT WRAP ARND MOIST
(PCPN) TO MOVE BACK INTO THAT AREA. JUST HAVE ISLTD OR SCTD PCPN
MENTIONED ACRS JUST ABT THE REMAINDER OF VA AND NC. CONTINUED
WITH CHC OF LGT SNOW OR SNOW SHOWERS MIXED IN WITH RAIN FOR AREAS
ALONG AND N OF I-64...ESPLY OVER THE LWR MD ERN SHR...WHERE LO-
LVL THICKNESSES WILL CONTINUE TO DECREASE THIS AFTN INTO TNGT AND
H85 TEMPS STAY BLO 0C. NOT EXPECTING MUCH IN THE WAY OF ACCUMULATIONS
DUE TO MILD/WET GROUND. BREEZY CONDITIONS OVER FAR ERN AREAS. HI
TEMPS THIS AFTN WILL RANGE FM THE MID 40S N TO THE UPR 40S/LWR 50S
S. LO TEMPS TNGT IN THE MID TO UPR 30S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/...
ASIDE FROM LINGERING -RA/-SN OVER EASTERN AREAS IN THE MRNG...DRY
WX EXPECTED ON THU. TIGHT GRADIENT BEHIND DEPARTING LO PRES WILL
MAINTAIN BREEZY CONDITIONS OVER THE AREA. TEMPS WILL CONTINUE TO
BE BLO NORMAL WITH NW FLOW AND UPR-LVL TROF ALONG THE EASTERN
SEABOARD...HIGHS RANGE FROM THE UPR 40S OVER THE LWR MD EASTERN
SHORE TO THE MID 50S OVER MUCH OF THE REST OF THE FA. SFC HI PRES
BLDS OVER THE AREA THU NGT INTO FRI AS TEMPS WARM SLGTLY...HIGHS
IN THE MID TO UPR 50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE UPPER LEVEL PATTERN WILL FLATTEN OUT THIS COMING WEEKEND INTO
EARLY NEXT WEEK. A BROAD RIDGE WILL BUILD INTO THE EASTERN U.S. THIS
WEEKEND WITH A SURFACE HIGH ESTABLISHING ITSELF OVER THE MID
ATLANTIC STATES. THIS WILL RESULTING IN DRY WEATHER AND A SLOW
WARMING TREND. THE HIGH SLIPS OFF THE COAST MONDAY AS A WEAKENING
TROUGH AND ASSOCIATED COLD FRONT APPROACH FROM THE WEST. HAVE
INCLUDED A 30 POP FOR SHOWERS TUESDAY...CONSISTENT WITH HPC
GUIDANCE. HIGH TEMPERATURES WILL RANGE FROM 60 TO 65 THIS WEEKEND
AND WARM TO THE UPPER 60S TO AROUND 70 OVER MOST OF THE AREA MONDAY
AND TUESDAY. LOWS IN THE 30S SATURDAY MORNING WARM TO THE 40S MONDAY
MORNING AND THE LOWER 50S TUESDAY MORNING.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
AS OF 19Z...NORTHERLY FLOW ON THE WEST SIDE OF A DEVELOPING STORM
SYSTEM OFFSHORE WILL CONTINUE ACRS THE TAF SITES THROUGH THURSDAY
MORNING.
CEILINGS MAINLY IN THE MVFR CATEGORY WILL CONTINUE EASTERN
PORTIONS INTO THE EARLY MORNING HOURS. AT SBY...IFR CEILINGS
DEVELOPING TO THE NORTH LOOK TO SPREAD TO THE TERMINAL AREA LATE
WEDNESDAY AFTN ALONG WITH A CHANGEOVER TO MIXED LIGHT SNOW AND RAIN.
SFC TEMPS SHOULD REMAIN ABOVE FREEZING. WITH PCPN MAINLY ON THE
LIGHT SIDE...KEPT VSBYS VFR OR MVFR. RICHMOND WILL REMAIN VFR WITH
NO SIGNIFICANT PCPN EXPECTED.
NORTHERLY WINDS GUSTING TO AROUND 20 TO 25 KNOTS AT SBY AND ORF AND
15 TO 20 KNOTS AT PHF AND ECG DIMINISH TNGT OR EARLY THURSDAY
MORNING. WINDS INCREASE ONCE AGAIN DURING THE DAY THURSDAY FROM THE
NW AS THE STORM SYSTEM OFFSHORE MOVES TO THE N AND E.
ONCE VFR TAKES OVER THURSDAY...IT SHOULD REMAIN THAT WAY INTO
MONDAY.
&&
.MARINE...
STRONG LO PRES (WELL) E OF THE VA CAPES CONTS TO INTENSIFY FURTHER
THROUGH TDA AS IT TRACKS TO THE NNE. WIND SPEEDS HAVE INCRSD...AND
WILL HAVE STRONG SCAS ON THE RIVERS/BAY/SND INTO THU...W/ GALES ON
THE OCN (HIGHEST SPEEDS NRN WTRS TO PSBLY 45 KT). THERE IS SOME
CONCERN ABT LO END GALES ON PORTIONS OF THE BAY...MNLY N OF NEW
POINT COMFORT. GUSTY NW WINDS WILL CONTINUE THROUGH THE END OF
THE WEEK AS THE STORM SYSTEM WILL BE SLOW TO EXIT THE NORTHEAST.
&&
.TIDES/COASTAL FLOODING...
UPDATE...ADDED COASTAL FLOOD ADVISORY FOR
DORCHESTER...WICOMICO...AND SOMERSET COUNTIES IN MARYLAND FROM
THURSDAY MORNING THROUGH MIDNIGHT THURSDAY NIGHT. AS WINDS BACK TO
THE NW OVERNIGHT TONIGHT...THEY WILL PERSIST INTO THURSDAY AND
HELP TO PUSH WATER ALONG THE ERN SHORES OF THE CHESAPEAKE BAY.
FORECAST ANOMALIES AT CAMBRIDGE ARE ONLY SHOWING TO BE AROUND
0.5 FT ABOVE NORMAL DURING THE THURSDAY MORNING HIGH TIDE
CYCLE...AND ABOUT 1.0 FT DURING THE SECOND HIGH TIDE CYCLE
THURSDAY NIGHT. HOWEVER...THE PERSISTENCE OF NW WINDS THROUGH THE
DAY IN ADDITION TO ALL LEVELS INCREASING (FORECAST/TIDE/SURGE)
DURING HIGH TIDE THURSDAY NIGHT WILL RESULT IN MINOR FLOODING...
WITH POTENTIALLY MODERATE COASTAL FLOODING ALONG THE ERN SHORES OF
CHES BAY. OTHERWISE...ONLY NUISANCE TYPE COASTAL FLOODING IS
EXPECTED.
PREVIOUS DISCUSSION...TIDAL ANOMALIES CONTG TO INCRS THROUGH THE
HIGH TIDE CYCLES THIS AFTERNOON AND TONIGHT. THERE RMNS
UNCERTAINTY ON HOW QUICKLY THE ANOMALIES LOWER ON THU. NNW WNDS TO
RMN STRONG/GUSTY INTO THU. HIGHEST THREAT FOR (ANY) COASTAL
FLOODING WILL BE THE LWR CHES BAY (SEWELLS POINT/CBBT)...ALG THE
ERN SIDE OF THE CHES BAY...AND FOR LOCATIONS LIKE OCEAN
CITY/CHINCOTEAGUE/WALLOPSISLAND - FROM THE BAYS INSTEAD OF THE
OCN. LATEST GUID INDICATING MODERATE FLOODING THIS
AFTN...APPROACHING SEVERE INVOF OCEAN CITY (BY TNGTS HI
TIDE)...MINOR FLOODING POSSIBLE ELSW. KEEPING COASTAL FLOOD
WARNING FOR CSTL LWR MD...AND HAVE ADDED AN ADVISORY FOR THE VA
ERN SHR...AND ALG THE LWR BAY (NORFOLK/VA BCH) (FOR THAT MINOR
FLOODING CONCERN). LASTLY...WILL NEED TO MONITOR AREAS OF THE LWR
MD ERN SHR ALG THE CHES BAY FROM DORCHESTER TO SOMERSET COUNTIES.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...COASTAL FLOOD WARNING UNTIL 6 AM EST THURSDAY FOR MDZ024-025.
COASTAL FLOOD ADVISORY FROM 6 AM THURSDAY TO MIDNIGHT EST
THURSDAY NIGHT FOR MDZ021>023.
NC...NONE.
VA...COASTAL FLOOD ADVISORY UNTIL 6 AM EST THURSDAY FOR VAZ095-
098>100.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THURSDAY FOR ANZ630>634-
638.
SMALL CRAFT ADVISORY UNTIL 7 AM EST FRIDAY FOR ANZ654-656-658.
GALE WARNING UNTIL NOON EST THURSDAY FOR ANZ650-652.
&&
$$
SYNOPSIS...MAS
NEAR TERM...MAS/TMG
SHORT TERM...MAS
LONG TERM...LSA
AVIATION...LSA
MARINE...ALB/BMD/SAM
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1242 PM EST WED NOV 7 2012
.SYNOPSIS...
STRONG LOW PRESSURE WELL EAST OF THE DELAWARE COAST...WILL MOVE
SLOWLY NORTH NORTHEAST THIS AFTERNOON INTO TONIGHT. HIGH PRESSURE
THEN BUILDS OVER THE AREA FOR LATER THURSDAY THROUGH THE UPCOMING
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
STRONG LO PRES WELL E OF THE DE CST...WILL MOVE SLOWLY NNE THIS
AFTN THRU TNGT. ADJUSTED POPS AND WORDING OVR THE REGION INTO THIS
EVENG...BASED ON LATEST SAT PIX AND RUC PARAMETERS. WILL HAVE
LIKELY POPS OVR THE LWR MD AND VA ERN SHR...AND POSSIBLY INTO THE
VA NRN NECK...DUE TO BEST CHC FOR SIGNIFICANT WRAP ARND MOIST
(PCPN) TO MOVE BACK INTO THAT AREA. JUST HAVE ISLTD OR SCTD PCPN
MENTIONED ACRS JUST ABT THE REMAINDER OF VA AND NC. CONTINUED
WITH CHC OF LGT SNOW OR SNOW SHOWERS MIXED IN WITH RAIN FOR AREAS
ALONG AND N OF I-64...ESPLY OVER THE LWR MD ERN SHR...WHERE LO-
LVL THICKNESSES WILL CONTINUE TO DECREASE THIS AFTN INTO TNGT AND
H85 TEMPS STAY BLO 0C. NOT EXPECTING MUCH IN THE WAY OF ACCUMULATIONS
DUE TO MILD/WET GROUND. BREEZY CONDITIONS OVER FAR ERN AREAS. HI
TEMPS THIS AFTN WILL RANGE FM THE MID 40S N TO THE UPR 40S/LWR 50S
S. LO TEMPS TNGT IN THE MID TO UPR 30S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
ASIDE FROM LINGERING -RA/-SN OVER EASTERN AREAS IN THE MRNG...DRY
WX EXPECTED ON THU. TIGHT GRADIENT BEHIND DEPARTING LO PRES WILL
MAINTAIN BREEZY CONDITIONS OVER THE AREA. TEMPS WILL CONTINUE TO
BE BLO NORMAL WITH NW FLOW AND UPR-LVL TROF ALONG THE EASTERN
SEABOARD...HIGHS RANGE FROM THE UPR 40S OVER THE LWR MD EASTERN
SHORE TO THE MID 50S OVER MUCH OF THE REST OF THE FA. SFC HI PRES
BLDS OVER THE AREA THU NGT INTO FRI AS TEMPS WARM SLGTLY...HIGHS
IN THE MID TO UPR 50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE UPPER LEVEL PATTERN WILL FLATTEN OUT THIS COMING WEEKEND INTO
EARLY NEXT WEEK. A BROAD RIDGE WILL BUILD INTO THE EASTERN U.S. THIS
WEEKEND WITH A SURFACE HIGH ESTABLISHING ITSELF OVER THE MID
ATLANTIC STATES. THIS WILL RESULTING IN DRY WEATHER AND A SLOW
WARMING TREND. THE HIGH SLIPS OFF THE COAST MONDAY AS A WEAKENING
TROUGH AND ASSOCIATED COLD FRONT APPROACH FROM THE WEST. HAVE
INCLUDED A 30 POP FOR SHOWERS TUESDAY...CONSISTENT WITH HPC
GUIDANCE. HIGH TEMPERATURES WILL RANGE FROM 60 TO 65 THIS WEEKEND
AND WARM TO THE UPPER 60S TO AROUND 70 OVER MOST OF THE AREA MONDAY
AND TUESDAY. LOWS IN THE 30S SATURDAY MORNING WARM TO THE 40S MONDAY
MORNING AND THE LOWER 50S TUESDAY MORNING.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
CSTL STORM CONTG TO INTENSIFY OFFSHR AS IT TRACKS NNE THROUGH TDA.
MVFR CONDS GENLY CONFINED TO ERN PORTION OF FA RIGHT NOW. MDL GUID
CONTS TO HAVE LITTLE IN THE WAY OF IFR CIGS DURING THE NEXT 24
HOURS SO DID NOT INCLUDE IN THE TAF EXCEPT FOR KECG AND KSBY. IFR
CAN BE EXPECTED INTERMITTENTLY DURING HEAVIER PCPN. NNW WINDS
GUSTY...STRONGEST NR THE CST. GUSTY N/NW WINDS CONTINUE THURSDAY
ESPECIALLY AT SBY AS PCPN AND LWR CIGS SLOLY PULL OUT. VFR SHOULD
CONTINUE THROUGH THE WEEKEND.
&&
.MARINE...
STRONG LO PRES (WELL) E OF THE VA CAPES CONTS TO INTENSIFY FURTHER
THROUGH TDA AS IT TRACKS TO THE NNE. WIND SPEEDS HAVE INCRSD...AND
WILL HAVE STRONG SCAS ON THE RIVERS/BAY/SND INTO THU...W/ GALES ON
THE OCN (HIGHEST SPEEDS NRN WTRS TO PSBLY 45 KT). THERE IS SOME
CONCERN ABT LO END GALES ON PORTIONS OF THE BAY...MNLY N OF NEW
POINT COMFORT. GUSTY NW WINDS WILL CONTINUE THROUGH THE END OF
THE WEEK AS THE STORM SYSTEM WILL BE SLOW TO EXIT THE NORTHEAST.
&&
.TIDES/COASTAL FLOODING...
UPDATE...ADDED COASTAL FLOOD ADVISORY FOR
DORCHESTER...WICOMICO...AND SOMERSET COUNTIES IN MARYLAND FROM
THURSDAY MORNING THROUGH MIDNIGHT THURSDAY NIGHT. AS WINDS BACK TO
THE NW OVERNIGHT TONIGHT...THEY WILL PERSIST INTO THURSDAY AND
HELP TO PUSH WATER ALONG THE ERN SHORES OF THE CHESAPEAKE BAY.
FORECAST ANOMALIES AT CAMBRIDGE ARE ONLY SHOWING TO BE AROUND
0.5 FT ABOVE NORMAL DURING THE THURSDAY MORNING HIGH TIDE
CYCLE...AND ABOUT 1.0 FT DURING THE SECOND HIGH TIDE CYCLE
THURSDAY NIGHT. HOWEVER...THE PERSISTENCE OF NW WINDS THROUGH THE
DAY IN ADDITION TO ALL LEVELS INCREASING (FORECAST/TIDE/SURGE)
DURING HIGH TIDE THURSDAY NIGHT WILL RESULT IN MINOR FLOODING...
WITH POTENTIALLY MODERATE COASTAL FLOODING ALONG THE ERN SHORES OF
CHES BAY. OTHERWISE...ONLY NUISANCE TYPE COASTAL FLOODING IS
EXPECTED.
PREVIOUS DISCUSSION...TIDAL ANOMALIES CONTG TO INCRS THROUGH THE
HIGH TIDE CYCLES THIS AFTERNOON AND TONIGHT. THERE RMNS
UNCERTAINTY ON HOW QUICKLY THE ANOMALIES LOWER ON THU. NNW WNDS TO
RMN STRONG/GUSTY INTO THU. HIGHEST THREAT FOR (ANY) COASTAL
FLOODING WILL BE THE LWR CHES BAY (SEWELLS POINT/CBBT)...ALG THE
ERN SIDE OF THE CHES BAY...AND FOR LOCATIONS LIKE OCEAN
CITY/CHINCOTEAGUE/WALLOPSISLAND - FROM THE BAYS INSTEAD OF THE
OCN. LATEST GUID INDICATING MODERATE FLOODING THIS
AFTN...APPROACHING SEVERE INVOF OCEAN CITY (BY TNGTS HI
TIDE)...MINOR FLOODING POSSIBLE ELSW. KEEPING COASTAL FLOOD
WARNING FOR CSTL LWR MD...AND HAVE ADDED AN ADVISORY FOR THE VA
ERN SHR...AND ALG THE LWR BAY (NORFOLK/VA BCH) (FOR THAT MINOR
FLOODING CONCERN). LASTLY...WILL NEED TO MONITOR AREAS OF THE LWR
MD ERN SHR ALG THE CHES BAY FROM DORCHESTER TO SOMERSET COUNTIES.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...COASTAL FLOOD WARNING UNTIL 6 AM EST THURSDAY FOR MDZ024-025.
COASTAL FLOOD ADVISORY FROM 6 AM THURSDAY TO MIDNIGHT EST
THURSDAY NIGHT FOR MDZ021>023.
NC...NONE.
VA...COASTAL FLOOD ADVISORY UNTIL 6 AM EST THURSDAY FOR VAZ095-
098>100.
MARINE...GALE WARNING UNTIL 6 AM EST THURSDAY FOR ANZ654-656-658.
GALE WARNING UNTIL NOON EST THURSDAY FOR ANZ650-652.
SMALL CRAFT ADVISORY UNTIL 6 PM EST THURSDAY FOR ANZ630>638.
&&
$$
SYNOPSIS...MAS
NEAR TERM...MAS/TMG
SHORT TERM...MAS
LONG TERM...LSA
AVIATION...ALB
MARINE...ALB/BMD/SAM
TIDES/COASTAL FLOODING...BMD/AKQ
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1132 AM EST WED NOV 7 2012
.SYNOPSIS...
STRONG LOW PRESSURE WELL EAST OF THE DELAWARE COAST...WILL MOVE
SLOWLY NORTH NORTHEAST THIS AFTERNOON INTO TONIGHT. HIGH PRESSURE
THEN BUILDS OVER THE AREA FOR LATER THURSDAY THROUGH THE UPCOMING
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
STRONG LO PRES WELL E OF THE DE CST...WILL MOVE SLOWLY NNE THIS
AFTN THRU TNGT. ADJUSTED POPS AND WORDING OVR THE REGION INTO THIS
EVENG...BASED ON LATEST SAT PIX AND RUC PARAMETERS. WILL HAVE
LIKELY POPS OVR THE LWR MD AND VA ERN SHR...AND POSSIBLY INTO THE
VA NRN NECK...DUE TO BEST CHC FOR SIGNIFICANT WRAP ARND MOIST
(PCPN) TO MOVE BACK INTO THAT AREA. JUST HAVE ISLTD OR SCTD PCPN
MENTIONED ACRS JUST ABT THE REMAINDER OF VA AND NC. CONTINUED
WITH CHC OF LGT SNOW OR SNOW SHOWERS MIXED IN WITH RAIN FOR AREAS
ALONG AND N OF I-64...ESPLY OVER THE LWR MD ERN SHR...WHERE LO-
LVL THICKNESSES WILL CONTINUE TO DECREASE THIS AFTN INTO TNGT AND
H85 TEMPS STAY BLO 0C. NOT EXPECTING MUCH IN THE WAY OF ACCUMULATIONS
DUE TO MILD/WET GROUND. BREEZY CONDITIONS OVER FAR ERN AREAS. HI
TEMPS THIS AFTN WILL RANGE FM THE MID 40S N TO THE UPR 40S/LWR 50S
S. LO TEMPS TNGT IN THE MID TO UPR 30S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
ASIDE FROM LINGERING -RA/-SN OVER EASTERN AREAS IN THE MRNG...DRY
WX EXPECTED ON THU. TIGHT GRADIENT BEHIND DEPARTING LO PRES WILL
MAINTAIN BREEZY CONDITIONS OVER THE AREA. TEMPS WILL CONTINUE TO
BE BLO NORMAL WITH NW FLOW AND UPR-LVL TROF ALONG THE EASTERN
SEABOARD...HIGHS RANGE FROM THE UPR 40S OVER THE LWR MD EASTERN
SHORE TO THE MID 50S OVER MUCH OF THE REST OF THE FA. SFC HI PRES
BLDS OVER THE AREA THU NGT INTO FRI AS TEMPS WARM SLGTLY...HIGHS
IN THE MID TO UPR 50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE UPPER LEVEL PATTERN WILL FLATTEN OUT THIS COMING WEEKEND INTO
EARLY NEXT WEEK. A BROAD RIDGE WILL BUILD INTO THE EASTERN U.S. THIS
WEEKEND WITH A SURFACE HIGH ESTABLISHING ITSELF OVER THE MID
ATLANTIC STATES. THIS WILL RESULTING IN DRY WEATHER AND A SLOW
WARMING TREND. THE HIGH SLIPS OFF THE COAST MONDAY AS A WEAKENING
TROUGH AND ASSOCIATED COLD FRONT APPROACH FROM THE WEST. HAVE
INCLUDED A 30 POP FOR SHOWERS TUESDAY...CONSISTENT WITH HPC
GUIDANCE. HIGH TEMPERATURES WILL RANGE FROM 60 TO 65 THIS WEEKEND
AND WARM TO THE UPPER 60S TO AROUND 70 OVER MOST OF THE AREA MONDAY
AND TUESDAY. LOWS IN THE 30S SATURDAY MORNING WARM TO THE 40S MONDAY
MORNING AND THE LOWER 50S TUESDAY MORNING.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
CSTL STORM CONTG TO INTENSIFY OFFSHR AS IT TRACKS NNE THROUGH TDA.
MVFR CONDS GENLY CONFINED TO ERN PORTION OF FA RIGHT NOW. MDL GUID
CONTS TO HAVE LITTLE IN THE WAY OF IFR CIGS DURING THE NEXT 24
HOURS SO DID NOT INCLUDE IN THE TAF EXCEPT FOR KECG AND KSBY. IFR
CAN BE EXPECTED INTERMITTENTLY DURING HEAVIER PCPN. NNW WINDS
GUSTY...STRONGEST NR THE CST. GUSTY N/NW WINDS CONTINUE THURSDAY
ESPECIALLY AT SBY AS PCPN AND LWR CIGS SLOLY PULL OUT. VFR SHOULD
CONTINUE THROUGH THE WEEKEND.
&&
.MARINE...
STRONG LO PRES (WELL) E OF THE VA CAPES CONTS TO INTENSIFY FURTHER
THROUGH TDA AS IT TRACKS TO THE NNE. WIND SPEEDS HAVE INCRSD...AND
WILL HAVE STRONG SCAS ON THE RIVERS/BAY/SND INTO THU...W/ GALES ON
THE OCN (HIGHEST SPEEDS NRN WTRS TO PSBLY 45 KT). THERE IS SOME
CONCERN ABT LO END GALES ON PORTIONS OF THE BAY...MNLY N OF NEW
POINT COMFORT. GUSTY NW WINDS WILL CONTINUE THROUGH THE END OF
THE WEEK AS THE STORM SYSTEM WILL BE SLOW TO EXIT THE NORTHEAST.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES CONTG TO INCRS THROUGH THE HIGH TIDE CYCLES THIS
AFTERNOON AND TONIGHT. THERE RMNS UNCERTAINTY ON HOW QUICKLY THE
ANOMALIES LOWER ON THU. NNW WNDS TO RMN STRONG/GUSTY INTO THU.
HIGHEST THREAT FOR (ANY) COASTAL FLOODING WILL BE THE LWR CHES BAY
(SEWELLS POINT/CBBT)...ALG THE ERN SIDE OF THE CHES BAY...AND FOR
LOCATIONS LIKE OCEAN CITY/CHINCOTEAGUE/WALLOPSISLAND - FROM THE BAYS
INSTEAD OF THE OCN. LATEST GUID INDICATING MODERATE FLOODING THIS
AFTN...APPROACHING SEVERE INVOF OCEAN CITY (BY TNGTS HI
TIDE)...MINOR FLOODING POSSIBLE ELSW. KEEPING COASTAL FLOOD
WARNING FOR CSTL LWR MD...AND HAVE ADDED AN ADVISORY FOR THE VA
ERN SHR...AND ALG THE LWR BAY (NORFOLK/VA BCH) (FOR THAT MINOR
FLOODING CONCERN). LASTLY...WILL NEED TO MONITOR AREAS OF THE LWR
MD ERN SHR ALG THE CHES BAY FROM DORCHESTER TO SOMERSET COUNTIES.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...COASTAL FLOOD WARNING UNTIL 6 AM EST THURSDAY FOR MDZ024-025.
NC...NONE.
VA...COASTAL FLOOD ADVISORY UNTIL 6 AM EST THURSDAY FOR VAZ095-
098>100.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THURSDAY FOR ANZ630>638.
GALE WARNING UNTIL 6 AM EST THURSDAY FOR ANZ654-656-658.
GALE WARNING UNTIL NOON EST THURSDAY FOR ANZ650-652.
&&
$$
SYNOPSIS...MAS
NEAR TERM...MAS/TMG
SHORT TERM...MAS
LONG TERM...LSA
AVIATION...ALB
MARINE...ALB/SAM
TIDES/COASTAL FLOODING...ALB
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
836 AM EST WED NOV 7 2012
.SYNOPSIS...
MIDWEST HIGH PRESSURE WILL PROVIDE DRY CONDITIONS AND A SLOW WARM
UP INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NOT MUCH IN THE WAY OF CHANGES WERE NEEDED THIS MORNING. CIRRUS
SHIELD ASSOCIATED WITH THE LOW ON THE COAST HAS EXPANDED OVER MUCH
OF WESTERN PA THIS MORNING. SO...MADE SOME CLOUD COVER ADJUSTMENTS
TO BETTER FIT SHORT TERM SATELLITE AND RAP MODEL OUTPUT.
PREVIOUS DISCUSSION FOLLOWS...
THE FORECAST AREA LOOKS TO BE SEEMINGLY SQUASHED BETWEEN HIGH
CLOUDS IN ASSOCIATION WITH AN UPPER LEVEL SYSTEM OVER VIRGINIA AND
ANOTHER SYSTEM DIVING SOUTHEASTWARD OVER THE LOWER OHIO VALLEY.
THIS LEAVES US IN A GENERAL AREA OF SUBSIDENCE THROUGH THE DAY
TODAY...MEANING THE CHANCES OF PRECIPITATION ARE VIRTUALLY NIL.
THE ONLY REAL DOWNSIDE TO THE FORECAST MAY BE HIGH CLOUDS WRAPPING
AROUND THE NORTHWESTERN PERIPHERY OF THE SYSTEM GETTING READY TO
RIDE NORTHEASTWARD OUT OF VIRGINIA. SKY GRIDS HAVE BEEN RAISED
NOMINALLY TO ACCOUNT FOR THIS...HOWEVER A GENERAL PARTLY CLOUDY
DAY STILL LOOKS IN STORE FOR MOST PLACES AWAY FROM THE RIDGES ON
WEDNESDAY.
WHILE ONLY JUST A VEIL OF CIRRUS WILL BE OVER THE AREA...A FAIR
AMOUNT OF SUNSHINE WILL BE SEEN IN MOST OF THE FORECAST AREA. EVEN
WITH THIS SUN...THE DAYS ARE GETTING PAINFULLY SHORT. WITH THIS
SHORT WINDOW FOR INSOLATION AS WELL AS 850 MB TEMPERATURES THAT
LOOK TO TREND DOWN 1 TO 2C BY AFTERNOON FROM THOSE RECORDED
YESTERDAY...HIGH TEMPERATURES ARE LIKELY TO FALL OFF A FEW DEGREES
TODAY. EXPLICIT MODEL GUIDANCE KEEPS MOST OF THE AREA IN THE LOWER
40S...WHILE STATISTICAL GUIDANCE IS A FEW DEGREES HIGHER THAN
THAT. GIVEN THE WEAK SUN ANGLE AND NORTHERLY FLOW OVER THE
AREA...TEMPERATURES WERE ADJUSTED ABRUPTLY DOWNWARD AND SIDE MORE
CLOSELY WITH THE EXPLICIT MODEL OUTPUT OVER STATISTICAL GUIDANCE.
FRIES
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
AN EXTREMELY STRONG MODEL AND ENSEMBLE CONSENSUS EXISTS THROUGH
THE WEEK AND INTO THE WEEKEND THAT INVOLVES VIRTUALLY EVERY SINGLE
PIECE OF AVAILABLE GLOBAL GUIDANCE PROJECTING AMPLIFIED RIDGING
BUILDING INTO THE MIDDLE ATLANTIC. THE RIDGE AXIS LOOKS TO SLOWLY
AMPLIFY INTO THE WEEKEND WITH ITS AXIS REACHING THE FORECAST AREA
BY SATURDAY MORNING. AS IT BUILDS...WARM ADVECTION LOOKS TO BE A
CONTINUAL FACTOR IN THE FORECAST OVER THE AREA...SO MUCH SO THAT
THE MODELS ACTUALLY BEGIN TO GENERATE SOME STRATIFORM
PRECIPITATION UP TOWARD LAKE ERIE BY THE END OF THE WEEK. THE
CONSENSUS SEEMS TO INDICATE THAT THE LOW LEVEL THERMAL GRADIENT
WILL BE JUST NORTH OF OUR FORECAST AREA...SO POPS FOR
PRECIPITATION WERE KEPT OUT OF THE FORECAST...BUT IT LOOKS TO BE
SOMETHING THAT FUTURE SHIFTS MAY HAVE TO CONTEND WITH GOING
FORWARD.
OTHERWISE...TEMPERATURES AT 850 MB RISE FROM AROUND 0C THIS
EVENING TOWARD +12C BY SATURDAY...WITH AT LEAST MODEST MIXING
BELOW THAT LEVEL COMING INTO PLAY BY THE WEEKEND. CLEARLY...GIVEN
THE WEAK SUN ANGLE AND SHORT LENGTH OF DAY...MIXING WILL NOT BE
DRY ADIABATIC OR PARTICULARLY EFFICIENT...HOWEVER IT SHOULD BE
STRONG ENOUGH TO ALLOW TEMPERATURES TO JUMP TOWARD THE 50S BY THE
START OF THE WEEKEND...WHICH IS NOW ABOVE NORMAL FOR NOVEMBER.
FRIES
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
THE ABRUPT WARMING DOES NOT STOP ON SATURDAY. AS A SHARP MID-LEVEL
TROUGH IS SET TO SHIFT FROM THE PACIFIC NORTHWEST TO START THE
WEEKEND INTO THE HEARTLAND BY SUNDAY...MID-LEVEL HEIGHTS...LOW
LEVEL MIXING...AND LOW LEVEL POSITIVE THERMAL ADVECTION ALL LOOK
TO KICK INTO OVERDRIVE OVER THE MIDDLE ATLANTIC. AS THIS
OCCURS...NOT ONLY DO 850 MB TEMPERATURES CONTINUE THEIR UPWARD
TRAJECTORY...BUT LOW LEVEL MIXING BELOW THEM LOOKS SET TO BECOME
MORE EFFICIENT BASED UPON A LARGER DEGREE OF MOMENTUM MIXING FROM
850 MB TO THE SURFACE. AS SUCH...LOW LEVEL PROFILES CLOSER TO DRY
ADIABATIC ARE EXPECTED BY SUNDAY AND EVEN MONDAY.
FROM A PURELY THERMAL PERSPECTIVE...SUNDAY LOOKS LIKELY TO BE THE
WARMEST DAY...IF ONLY NOMINALLY WARMER THAN MONDAY...ON THE HEELS
OF WARM ADVECTION PUSHING 850 MB TEMPERATURES INTO THE +12 TO +14C
RANGE AT 850 MB. HOWEVER...WHILE SOME MODEST COOLING AT 850 MB IS
NOTED BY MONDAY AFTERNOON AS MID-LEVEL HEIGHTS START TO FALL A BIT
AHEAD OF THE NEXT SYSTEM...THE LOW LEVEL THERMAL TONGUE REMAINS
OVER THE AREA AND THERMODYNAMIC PROFILES LOOK TO BECOME VERY
EFFICIENTLY MIXED JUST AHEAD OF THE INCOMING SHORT WAVE. AS
SUCH...TEMPERATURES ON MONDAY SHOULD NOT FALL VERY MUCH AT ALL
RELATIVE TO SUNDAY. HOWEVER...BY TUESDAY...THE CONSENSUS BRINGS IN
DECIDEDLY COLDER AIR. THIS MEANS AN ABRUPT END TO OUR BRIEF PERIOD
OF UNSEASONABLY WARM WEATHER AND A HARSH RETURN TO REALITY THAT
OLD MAN WINTER HAS YET TO EVEN BARE HIS FROSTY TEETH AT THE UPPER
OHIO VALLEY. FRIES
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS WILL CONTINUE UNDER HIGH PRESSURE TODAY AND
TONIGHT. WINDS WILL REMAIN AROUND 5KTS OUT OF THE EAST-NORTHEAST.
.OUTLOOK.../THURSDAY THROUGH SUNDAY/...
VFR CONDITIONS WILL CONTINUE TO PREVAIL FOR MUCH OF THE PERIOD
THOUGH SUNDAY WITH HIGH PRESSURE BUILDING IN. SOME BRIEF CEILING
RESTRICTIONS ARE POSSIBLE IN A NW FLOW THURSDAY EVENING INTO
FRIDAY MORNING...BUT CONFIDENCE IS RELATIVELY LOW.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
514 PM CST THU NOV 8 2012
.UPDATE...FOR 00Z AVIATION DISCUSSION BELOW
&&
.DISCUSSION.../ISSUED 255 PM CST THU NOV 8 2012/
MAIN WEATHER STORY FOR THE FORECAST PERIOD WILL BE THE EFFECTS OF
THE STORM SYSTEM COMING IN OVER THE WEEKEND BRINGING A MIX OF PCPN
AND A MAJOR SWING IN TEMPERATURE.
IN THE NEAR TERM...A COLD FRONT HAS BEEN MAKING STEADY SE PROGRESS
TODAY NOW LYING FROM JUST W OF DLH TO STC TO THE OTG AREA. BROAD
AREA OF MVFR CIGS HAS BEEN FOLLOWING THE FRONT. S WINDS AHD OF THE
FRONT HAVE PUSHED TEMPS INTO THE MID 50S ACROSS S MN. TONIGHT FRONT
WILL CONTINUE TO DROP SE INTO EXT SE MN AS HIGH PRESSURE BUILDS OUT
OF THE CNDN PRAIRIES ACRS N MN. EXPECT MVFR CLDS TO PUSH AT LEAST
ACRS THE NW 1/2 OF CWA.
ON FRIDAY THE CDFNT WILL FIND A HOME ACROSS S WI INTO CNTL IA BEFORE
MOVING BACK NORTH AS A WARM FRONT FRIDAY NIGHT AND SATURDAY AHEAD OF
APPROACHING TROF. THIS SYSTEM FAIRLY VIGOROUS WITH 12Z 500 MB HEIGHT
FALLS OF AS MUCH AS 180 METERS IN THE PACIFIC NW. VERY WARM AIR
ADVECTED NORTH AHEAD OF THIS SYSTEM AS WARM FRONT LIFTS INTO S MN/W
WI ON SATURDAY WITH 850 MB TEMPS OF +15C. TEMPS ON FRIDAY PROBABLY
A FEW DEGREES COOLER THAN TODAY WITH MORE CLOUDS EXPECTED. TEMPS ON
SATURDAY A BIT PROBLEMATIC WITH VERY WARM AIR IN PLACE ACROSS SE 1/2
AREA...BUT SOME THREAT OF STRATUS. GFS/NAM BOTH DO...HOWEVER...BRING
A DRY SLOT INTO SE MN AHEAD OF APRCHG SFC LOW. THUS WILL CONTINUE
WITH THE 60 TO 65 DEGREE TEMPS. BIG COOL DOWN FOR SUNDAY WITH GUSTY
NOW WINDS IN WAKE OF CDFNT.
AS FAR AS PCPN CONCERNED...REMOVED DRIZZLE FOR FRIDAY WITH PROGGED
SOUNDING LOOKING A BIT TOO DRY UNTIL FRIDAY EVENING. ON FRIDAY NIGHT
FIRST SURGE OF MOISTURE TRANSPORT PUSHES INTO AREA WITH PWATS
INCREASING TO 1 INCH ACROSS S MN INTO WI. BY 12Z SAT MID LEVELS ALSO
DESTABALIZE ENUF FOR A THREAT OF THUNDER IN SE AREAS. BETTER THREAT
OF PCPN FOR SATURDAY AFTN WILL BE ACRS N CWA...N OF WRMFNT.
GFS/ECMWF/NAM ALL PRETTY CLOSE ON TRACK OF SFC LOW CARRYING IT TO
ARND RWF BY 00Z SUNDAY TO N OF MSP BY 06Z AND N OF DLH BY 12Z
SUNDAY. SHUD BE ANOTHER ROUND OF SHOWERS WITH PSBL THUNDER IN SE
AREAS ON SATURDAY LT AFTN/EVE AHD OF APRCHG CDFNT. COLD AIR WRAPS IN
NW 1/2 OF CWA BY 12Z SUNDAY WHICH SHUD CHANGE PCPN QUICKLY TO
SNOW...DOUBT THERE WOULD BE MUCH THREAT OF FRZG PCPN WITH RAPID
SURGE OF COLD AIR. DURING THE DAY ON SUNDAY PCPN WILL BE
TRANSITIONING TO MAINLY -SN ACRS AREA...BUT AMOUNTS WILL BE SMALL
WITH QPF MAINLY N AND E OF AREA. MAY SEE A COUPLE INCHES...MAINLY
LATE SATURDAY NIGHT/ERLY SUNDAY IN FAR NW CWA.
COOL TO START OUT THE UPCOMING WEEK WITH MODERATING TEMPS AS WE
TRANSISTION TO A SW FLOW. PRETTY QUITE WEATHER-WISE WITH NEXT
THREAT OF SIG PCPN ABOUT FRIDAY AS GFS/ECMWF CARVE OUT ANOTHER TROF
LATE IN WEEK IN W U.S. BRINGING UPPER TROF NE TOWARD OUR AREA FRIDAY.
&&
.AVIATION.../00Z TAF ISSUANCE/
PRIMARY AVIATION CONCERN THIS ISSUANCE IS THE TIMING OF THE
ARRIVAL OF MVFR CIGS. EXTENSIVE DECK OF CIGS FROM 1500-2000FT WAS
NOTED ACROSS THE NWRN TWO THIRDS OF MN AND THE ERN DAKOTAS AT 23Z.
WHILE THE SOUTH/SOUTHEAST PROGRESSION OF THIS DECK WILL LIKELY SLOW A
BIT AS LLVL WINDS VEER TO NORTHEAST/EASTERLY TONIGHT...STILL THINK
THERE WILL BE ENOUGH PUSH TO GET AN MVFR DECK TO TAF SITES BY OR
SHORTLY AFTER DAYBREAK FRIDAY. THE NAM AND SREF LLVL RH PROGS AND
CIG PROBABILITIES ARE TOO DRY/HIGH AS COMPARED TO CURRENT OBS...SO
HAVE LEANED TOWARD THE GFS AND RAP WHICH ARE INITIALIZING MUCH
BETTER AT THE 925-850MB LEVEL. THIS RESULTS IN A MORE PESSIMISTIC
TAF PACKAGE...WHICH FEATURES PREDOMINANT CIGS CIRCA 2KFT
DEVELOPING OVERNIGHT AND PERSISTING ON FRIDAY. SFC WINDS WILL
CONTINUE TO VEER TO NORTHEASTERLY TONIGHT AND THEN BECOME
PRIMARILY EASTERLY FOR FRIDAY.
KMSP...
CONFIDENCE IS RELATIVELY HIGH FOR VFR CONDITIONS UNTIL 06Z...AND
THEN IT LOWERS AS MODELS DIVERGE A BIT WITH RESPECT TO THE TIMING
OF THE ARRIVAL OF AN MVFR DECK. BEST ESTIMATE AT THIS POINT IS
THAT AN MVFR DECK /2000 FT/ WILL MOVE INTO KMSP BY 14Z...AND THEN
PERSIST THROUGH THE TAF PERIOD. NORTHWEST WINDS WILL VEER TO THE
NORTHEAST BY 03Z...THEN BECOME EASTERLY BY 14Z.
/OUTLOOK FOR KMSP/
SAT...MVFR/IFR CEILINGS AND -SHRA POSSIBLE
EARLY. SLIGHT CHANCE OF LIFR CIGS. WINDS ESE AT 10G15KTS.
SUN...FROPA WITH WINDS BECOMING NW 10-20 KTS. IFR POSSIBLE WITH
-RASN.
MON...VFR. WINDS WNW AT 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BAP/LS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
533 PM CST THU NOV 8 2012
.AVIATION...00Z TAF. VFR CONDITIONS ARE EXPECTED INTO THE FIRST
PART OF TONIGHT...BUT POTENTIAL EXISTS FOR INCREASING LOW CLOUDS
IN THE MVFR CATEGORY BEHIND SFC TROUGH/COOL FRONTAL BOUNDARY.
STRATUS DECK IS CURRENTLY LOCATED IN SOUTH DAKOTA AND IS MIGRATING
SOUTHWARD. RAP NOSES THIS CLOUD COVER INTO NORTHERN NEBRASKA
AROUND 09Z AND WILL GO AHEAD INTRODUCE AN MVFR CIG FOR KGRI FOR A
FEW HOURS. POTENTIAL EXISTS FOR REDUCED VSBY IN BR ALONG THE
PERIPHERY OF THE LOW CLOUDS. ATTM...EXPECT LOW CLOUDS TO SCATTER
FRIDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 358 PM CST THU NOV 8 2012/
SHORT TERM...THROUGH SUNDAY AFTERNOON...A STRONG LOW PRESSURE
SYSTEM DIGGING OFF THE WEST COAST WILL CROSS THE INTERMOUNTAIN
WEST THIS WEEKEND WITH A STRONG COLD FRONT EXPECTED TO BRING
SIGNIFICANT CHANGES TO THE WEATHER PATTERN BY SATURDAY NIGHT OR
SUNDAY.
IN THE MEANTIME...EXPECT THE WEAK COLD FRONT SLOWLY TRAVERSING THE
LOCAL AREA THIS AFTERNOON TO EVENTUALLY STALL NEAR THE KS/NE LINE
OVERNIGHT...WITH LITTLE CHANGE IN AIRMASS NOTED OTHER THAN A SHIFT
IN THE WINDS TO THE NORTH. WITH THE COLD FRONT POSITIONED TO THE
SOUTH OF THE TRI CITIES AREA...EXPECT THE POSSIBILITY OF SOME LOW
STRATUS DEVELOPMENT ACROSS MUCH OF SOUTH CENTRAL NEBRASKA BY
FRIDAY MORNING...WITH MODEL GUIDANCE ALL OVER THE MAP FOR
AFTERNOON TEMPERATURES TOMORROW AFTERNOON DEPENDING WEATHER THIS
STRATUS CLEARS OR OVERCAST SKIES REMAIN THROUGH THE AFTERNOON.
WITH THE LATEST NAM A BIT SLOWER LIFTING THIS BOUNDARY NORTH LATE
FRIDAY NIGHT...THE POSSIBILITY FOR AN OVERCAST DAY IS LOOKING MORE
PLAUSIBLE...BUT STUCK WITH A MORE OPTIMISTIC SOLUTION...WITH SOME
CLEARING FORECAST FOR LATER IN THE DAY. OTHERWISE...KEPT
TEMPERATURES IN THE UPPER 50S AND LOWER 60S NORTH OF THE BOUNDARY
DURING THE DAY FRIDAY...AS INCREASED CLOUD COVER IS EXPECTED TO
KEEP AFTERNOON READINGS DOWN A FEW DEGREES FROM TODAYS PLEASANT
TEMPERATURES.
THEREAFTER...FOCUS WILL SHIFT TO THE NEXT COLD FRONT EXPECTED TO
CROSS THE PLAINS SATURDAY AFTERNOON AND EVENING...WITH A VERY
NICE...ALBEIT FAIRLY WINDY DAY...ANTICIPATED AHEAD OF THIS
SYSTEM. HOWEVER...WITH A VERY SHARP TEMPERATURE GRADIENT...NEAR
1000 J/KG OF MU CAPE AHEAD OF THE FRONT...AND PLENTY OF
SHEAR...COULD SEE SOME STRONG OR SEVERE THUNDERSTORMS DEVELOP JUST
AHEAD OF THE APPROACHING FRONT LATE IN THE DAY. NOT
SURPRISINGLY...MUCH OF THE SOUTHEASTERN HALF OF THE FORECAST AREA
IS IN THE LATEST SPC OUTLOOK AND WENT AHEAD AND DECIDED TO ADD
SEVERE WORDING TO FORECAST FOR PORTIONS OF THE LOCAL AREA DURING
THE 00Z-06Z TIME FRAME SATURDAY EVENING.
BEHIND THIS FRONT...FOCUS WILL TURN TO THE POTENTIAL FOR A LIGHT
DUSTING OF SNOW AS TEMPERATURES PLUMMET AND SOME LINGERING
MOISTURE IS ANTICIPATED BEHIND THE APPROACHING FRONT. WITH BEST
MOISTURE AND FORCING ACROSS THE NORTHWESTERN FRINGES OF THE LOCAL
AREA SATURDAY EVENING...WENT AHEAD AND ADDED SOME LIGHT
SNOWFALL ACCUMULATIONS TO THE FORECAST...UP TO AROUND AN
INCH...MAINLY IN VALLEY...GREELEY AND WESTERN DAWSON COUNTIES.
OTHERWISE...LITTLE MORE THAN A DUSTING OF SNOW IS ANTICIPATED
DURING THE LATE NIGHT/EARLY MORNING HOURS SUNDAY ACROSS THE
REMAINDER OF THE FORECAST AREA...AS THIS FRONT IS EXPECTED TO
RAPIDLY TRACK EASTWARD BY SUNDAY AFTERNOON. THIS WILL RESULT IN A
NOTICEABLY COOLER DAY SUNDAY...WITH ALL AREAS EXPECTED TO
EXPERIENE AN UNSEASONABLY COLD SUNDAY AFTERNOON...WITH HIGH TEMPS
EXPECTED TO RANGE ONLY FROM THE UPPER 20S ACROSS THE NORTH TO THE
MIDDLE TO UPPER 30S ACROSS NORTH CENTRAL KANSAS.
LONG TERM...LONG TERM...SUNDAY NIGHT THROUGH THURSDAY.
MAIN CONCERNS FOR THE PERIOD WILL FOCUS ON LOW TEMPERATURES SUNDAY
EVENING.
BY SUNDAY EVENING...THE STRONG SURFACE LOW WILL CONTINUE TO PUSH
EASTWARD OUT OF THE PLAINS. AS THE TRAILING UPPER LEVEL SYSTEM
QUICKLY FOLLOWS...THE MAIN TROUGH AXIS WILL SHIFT THROUGH THE PLAINS
AROUND MIDNIGHT SUNDAY NIGHT. A MODERATELY AMPLIFIED UPPER LEVEL
RIDGE IS EXPECTED TO BUILD IN ACROSS THE ROCKIES HEADING INTO THE
MONDAY MORNING TIME FRAME...RESULTING IN NORTHWEST FLOW ACROSS THE
PLAINS. AT THE SURFACE HIGH PRESSURE WILL SETTLED ACROSS THE REGION.
WITH INCREASED SUBSIDENCE...EXPECT DECREASING CLOUD COVER THROUGH
THE OVERNIGHT HOURS. ALTHOUGH MODELS SUGGEST WARMER SURFACE
TEMPERATURES...850 TEMPERATURES ON THE ORDER OF -8 TO -10 DEGREES
CELSIUS...COMBINED WITH CLEAR SKIES OVERNIGHT SHOULD ALLOW FOR
STRONG RADIATIONAL COOLING. LOWERED MONDAY MORNING TEMPERATURES A
BIT TO REFLECT THESE ISSUES. CURRENT FORECAST SUGGESTS LOWER TEENS
NORTHWEST TO LOWER 20S SOUTHEAST.
TEMPERATURES ON MONDAY WILL REMAIN ABOUT 10 DEGREES BELOW
NORMAL...WITH UPPER 30S NORTH TO MID 40S SOUTH...AS THE PLAINS
REMAIN UNDER NORTHWEST FLOW WITH COOLER TEMPERATURES IN THE MID
LEVELS. EXPECT MOSTLY SUNNY SKIES WITH LIGHT WESTERLY WINDS AS THE
SURFACE HIGH SHIFTS EASTWARD.
MONDAY NIGHT THROUGH WEDNESDAY...THE UPPER LEVEL RIDGE SLOWLY BEGINS
TO BREAK DOWN BECOMING MORE ZONAL FLOW...WHILE A WEAK SURFACE LOW
DEVELOPS ALONG THE FRONT RANGE. LIGHT SOUTHWEST BREEZES AT THE
SURFACE WILL HELP WARM TEMPERATURES UP SLIGHTLY SO TUESDAY AND
WEDNESDAY HIGHS WILL BE CLOSER TO NORMAL IN THE UPPER 40S TO LOWER
50S.
BY WEDNESDAY NIGHT...ANOTHER UPPER LEVEL TROUGH WILL BEGIN TO DIG OUT
ACROSS THE SOUTHERN WEST COAST...WITH A DEVELOPING LOW PRESSURE
SYSTEM ACROSS SOUTHERN CALIFORNIA. THIS SYSTEM LOOKS TO KICK OUT
ACROSS THE DESERT SOUTHWEST ON THURSDAY...WITH THE SURFACE LOW
ENTERING COLORADO BY THE END OF THE PERIOD. WHILE ALL BLENDS TRIED
TO GENERATE SOME QPF THROUGH THE LAST PERIOD OF DAY 7...NONE OF THE
MODELS REFLECTED ANY HINT THAT THIS SYSTEM WOULD IMPACT ANY PORTION
OF THE CWA BEFORE DAY 8...THUS PULLED ALL POPS IN THE EXTENDED.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
616 PM EST THU NOV 8 2012
.SYNOPSIS...
HIGH PRESSURE WILL KEEP DRY CONDITIONS AND MOSTLY CLEAR SKIES
INTO THIS WEEKEND. AS THE HIGH SHIFTS EASTWARD FRIDAY...A WARMING
TREND WILL BEGIN THAT WILL BRING UNSEASONABLY WARM TEMPERATURES
FOR THE WEEKEND. THE NEXT CHANCE FOR RAIN WILL OCCUR LATE SUNDAY
NIGHT INTO MONDAY WITH THE APPROACH AND PASSAGE OF A COLD FRONT.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
HIGHLY AMPLIFIED PATTERN WITH AN UPPER LEVEL RIDGE OVER THE
NATIONS MID SECTION TO BEGIN BUILDING EAST INTO THE REGION.
SURFACE RIDGE AXIS OVER THE OHIO VALLEY TO SLIDE JUST TO OUR EAST
LATE TONIGHT WITH THE LOW LEVEL FLOW BECOMING SRLY. MSTR BETWEEN
900-850MB LOCATED TO OUR WEST OVER INDIANA BEGINNING TO PUSH INTO
W CNTRL OHIO. QUESTION REVOLVES AROUND HOW THESE CLOUDS WILL
AFFECT ILN/S FA. THE FLOW AT THIS LEVEL BECOMES WESTERLY AROUND 15
KTS WHICH WILL ALLOW THE CLOUDS TO CONTINUE TO PUSH EAST INTO
ILN/S WESTERN FA EARLY THIS EVENING. IN WAA PATTERN EXPECT A
GENERAL DECREASE IN COVERAGE OF THESE CLOUDS AS THEY PUSH EAST.
LATEST RAP RUN SUPPORTS THIS SOLN BRINGING THE BEST COVERAGE OF
CLOUDS INTO WEST CNTRL OHIO THIS EVENING AND THEN DIMINISHING
THEM. OTHERWISE...EXPECT MAINLY CLEAR SKY CONDITIONS WITH ONLY
SOME HIGH LEVEL CLOUDS SPILLING IN. EXPECT LOWS TO BE A LTL MILDER
THAN THIS MORNING...RANGING FROM UPPER 20S NE TO THE LOWER/MID 30S
SW.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
UPPER LEVEL RIDGE TO BUILD EAST INTO THE REGION ON FRIDAY. THIS
WILL ALLOW FOR HEIGHT/THICKNESS RISES. EXPECT MAINLY SUNNY SKY
CONDITIONS FRIDAY WITH ONLY THIN HIGH LEVEL CLOUDS SPILLING IN.
UNDER WAA AND SUNSHINE EXPECT HIGHS TO BE 5 TO 10 DEGREES ABOVE
NORMAL...RANGING FROM THE MID 50S NE TO THE LOWER 60S SW.
ISENTROPIC LIFT DEVELOPS LAT FRIDAY AFTN/FRIDAY NIGHT WITH THE
BEST LIFT AND MOISTURE TO REMAIN TO OUR NORTH ACRS THE GREAT
LAKES. WILL ALLOW FOR AN INCREASE IN MID/HI LEVEL CLOUDS FRIDAY
NIGHT WITH THE BEST COVERAGE ACRS THE NORTH. THESE CLOUDS AND
SRLY FLOW WILL KEEP TEMPS ON THE MILD SIDE FRIDAY NIGHT. LOWS ARE
EXPECTED TO RANGE FROM THE UPPER 30S NE TO THE LOWER/MID 40S SW.
GOOD WAA ON SATURDAY WITH THINNING CLOUDS ALLOWING FOR MOSTLY
SUNNY SKY CONDITIONS. 8H TEMPS WARM UP TO BETWEEN +13 AD +14 DEG
C. EXPECT HIGHS TO BE ABOUT 15 DEGREES ABOVE NORMAL...RANGING FROM
THE MID 60S NORTH TO NEAR 70 SOUTH.
SOME INCREASE IN HIGH LEVEL CLOUDS LKLY SAT NIGHT. UNDER CONTD
SRLY FLOW MILD CONDITIONS WILL PERSIST WITH LOWS RANGING FROM THE
MID 40S E TO THE UPPER 40S W.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
A SOUTHERLY FLOW BEHIND DEPARTING HIGH PRESSURE WILL KEEP WARM...
BREEZY AND DRY CONDITIONS OVER THE REGION ON SUNDAY. A STRONG COLD
FRONT WILL AFFECT THE AREA ON MONDAY. WENT WITH CATEGORICAL
SHOWERS...AND ISOLATED THUNDERSTORMS IN A REGIME OF MARGINAL
ELEVATED INSTABILITY. SYNOPTIC SCALE WINDS ACCOMPANYING THE FRONT
MAY GUST NEAR 25 KNOTS.
MODELS INDICATE A RATHER RAPID EXIT FOR THE FRONT...WITH DRY
WEATHER RETURNING ON TUESDAY. THE DRY PERIOD IS EXPECTED TO LAST
THROUGH THURSDAY AS HIGH PRESSURE TRAVELS ACROSS OHIO ON A WESTERLY
FLOW ALOFT.
TEMPERATURES WILL RISE INTO THE 60S ON SUNDAY UNDER MOSTLY SUNNY
SKIES. HIGHS IN THE 50S AND 60S ARE FORECAST FOR MONDAY DURING THE
TRANSITION TO A COOLER AIRMASS BEHIND THE FRONT. READINGS ON TUESDAY
AND WEDNESDAY WILL TOP OUT IN THE 40S...WITH A RISE TO AROUND 50
POSSIBLE THURSDAY IN THE RETURN FLOW BEHIND THE HIGH.
&&
.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
SURFACE HIGH PRESSURE WILL PROVIDE GENERALLY TRANQUIL CONDITIONS
THROUGH THE TAF PERIOD. CLEAR SKIES AND LIGHT WINDS OVERNIGHT WILL
MAKE SOME FOG POSSIBLE...BUT HIGHER TEMPERATURES THAN LAST NIGHT
(WITH SIMILAR DEWPOINTS) WILL LIMIT THIS FROM BECOMING WIDESPREAD.
MVFR FOG HAS BEEN INCLUDED AT KILN/KLCK...WITH THE USUAL
CONDITIONS BELOW AIRPORT MINIMUMS AT KLUK.
WHILE SOME PATCHY STRATOCUMULUS MAY PERSIST OVERNIGHT AND EARLY
FRIDAY MORNING ACROSS NORTHERN OHIO AND INDIANA...IT IS EXPECTED
THAT THIS WILL NOT AFFECT THE NORTHERN TAF SITES.
AS WINDS SHIFT FROM WEST TO SOUTHWEST ON FRIDAY (GENERALLY UNDER
10 KNOTS)...HIGH CLOUDS WILL BEGIN TO MOVE INTO THE AREA. MID
LEVEL MOISTURE WILL BE INCREASING AT THE END OF THE TAF
PERIOD...AS WINDS SHIFT TO THE SOUTH.
.OUTLOOK...MVFR CEILINGS AND VISIBILITIES ARE POSSIBLE FROM MONDAY
INTO MONDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...AR
NEAR TERM...AR
SHORT TERM...AR
LONG TERM...CONIGLIO
AVIATION...HATZOS
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
900 PM CST THU NOV 8 2012
.DISCUSSION.../ISSUED AT 900 PM CST/
COLD FRONT MOVING SOUTHEAST THROUGH NORTHWEST IOWA WITH STRATUS
SPREADING SOUTH ACROSS CWA. CURRENTLY STRATUS IS NEAR I90 AND WEST
OF BUFFALO RIDGE IN SOUTHWEST MINNESOTA. STRATUS MAY HAVE A HARD
TIME GETTING EAST OF BUFFALO RIDGE TONIGHT WITH THE LOW LEVEL
NORTHEAST FLOW KEEPING THE CLOUDS TO THE WEST. WILL TREND MOST OF
NIGHT CLOUDS SAGGING SOUTH WEST OF BUFFALO RIDGE...BUT OVER
TIME...STRATUS SHOULD MOVE IN. CLOUDS SHOULD HELP TO HOLD UP
TEMPERATURES TONIGHT...AND DID BUMP UP A FEW DEGREES ACROSS THE
NORTH.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
A BROAD AREA OF STRATUS REMAINS POISED TO PUSH SOUTHWARD INTO OUR
AREA THROUGH THE OVERNIGHT HOURS...AND HAS ALREADY MOVED INTO KHON
AT THIS TIME. CONFIDENCE IS SOMEWHAT LOW IN REGARD TO HOW FAR SOUTH
THE STRATUS WILL MAKE IT...WITH MODELS NOT HANDLING IT VERY WELL.
THE RAP MODEL SEEMS TO HAVE THE BEST HANDLE ON IT...AND EXPECT THE
LOW CLOUDS TO SPREAD INTO THE INTERSTATE 90 CORRIDOR AFTER 03Z...AND
THEN LESS CONFIDENCE AS TO WHETHER IT WILL MAKE IT ALL THE WAY INTO
KSUX BY THE EARLY MORNING HOURS OF FRIDAY. THE STRATUS DOES APPEAR
TO HANG ON THROUGH THE DAY ON FRIDAY.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 356 PM CST/
FRONTAL BOUNDARY WILL CONTINUE TO WORK ITS WAY SOUTHEAST ACROSS THE
CWA THIS AFTERNOON AND EVENING. MAIN FORECAST ISSUE TONIGHT INTO
TOMORROW WILL BE CLOUD COVER AND TEMPERATURES. STRATUS DECK
ASSOCIATED WITH THE LOW LEVEL COLD AIR ADVECTION PUSH IS CURRENTLY
MOVING SOUTH INTO NORTHERN SOUTH DAKOTA. MODELS HANDLE THIS FEATURE
DIFFERENTLY. LOOKS LIKE THE NAM IS DECOUPLING THE BOUNDARY LAYER TOO
MUCH TONIGHT...WHICH ACTS TO KEEP THE STRATUS AT BAY. FEEL LIKE
SOMETHING CLOSER TO THE RAP SOLUTION IS MOST LIKELY...WHERE THE COLD
AIR ADVECTION KEEPS THE BOUNDARY LAYER MIXED ENOUGH TO KEEP THE
STRATUS LOCKED IN AND SPREADING SOUTH. COULD EVEN SEE SOME SPOTTY
DRIZZLE IN THE EASTERLY UPSLOPE LOCATIONS OF SOUTHWEST MINNESOTA.
THUS WILL LEAN TOWARDS THIS SOLUTION WITH CLOUDS INCREASING FROM
NORTH TO SOUTH TONIGHT. LOWS MAINLY IN THE 30S...WITH THE CLOUDS AND
BREEZE PREVENTING TEMPS FROM FALLING TOO FAR.
ON FRIDAY...LOW STRATUS WILL BEGIN TO ERODE FROM SOUTH TO NORTH.
HOWEVER AT THE SAME TIME...SOUTHEASTERLY WINDS WILL ADVECT IN
ADDITIONAL MOISTURE AROUND 850 MB...ALLOWING ANOTHER STRATUS DECK TO
QUICKLY FORM. THUS THINK MUCH OF THE AREA STAYS CLOUDY THROUGH THE
DAY...WITH SOUTHERN AREAS HAVING THE BEST CHANCE OF SEEING A BIT OF
MORNING SUN. MOISTURE WILL CONTINUE TO DEEPEN THROUGH THE DAY...WITH
PORTIONS OF SOUTHWEST MINNESOTA AND NORTHWEST IOWA POSSIBLY SEEING
SOME DRIZZLE BY MID AFTERNOON AS WE SEE WEAK LIFT IN THE NEARLY
SATURATED 0-1 KM LAYER. FORECAST CONFIDENCE IS OVERALL PRETTY LOW ON
FRIDAY. THE NAM IS A LOT SLOWER THAN THE GFS WITH STRATUS
FORMATION...WITH THE GFS THE FASTEST. THE FORECAST FOLLOWS CLOSEST
TO THE GFS SOLUTION...WHICH APPEARS TO BE HANDLING THINGS BEST AT
THE CURRENT TIME. THUS WITH THE CLOUDS AROUND...LOWERED HIGHS A FEW
DEGREES FOR TOMORROW...GENERALLY MID TO UPPER 40S NORTH TO MID 50S
SOUTHEAST. IF A SOLUTION CLOSER TO THE NAM PANS OUT RESULTING IN A
LONGER PERIOD OF SUN...HIGHS WILL BE A GOOD 5 DEGREES WARMER...AND
IF THE CLOUDS STAY LOCKED IN EVEN MORE THAN EXPECTED...HIGHS WOULD
BE A FEW DEGREES COOLER THAN CURRENT FORECAST. /CHENARD
COMPLICATED FORECAST ANTICIPATED FOR THE WEEKEND WITH THE WELL
ADVERTISED SURFACE LOW AND BROAD SURFACE TROUGH TRACKING THROUGH THE
AREA. FOR FRIDAY NIGHT...LOW STRATUS WILL REMAIN A CONCERN WITH ALL
MODELS KEEPING A LOW CLOUD DECK IN PLACE OVERNIGHT. THE GFS AND
ECMWF CONTINUE TO INDICATE A DEEPER MOIST LAYER THAN THE NAM...WHICH
POINTS TO A GREATER POTENTIAL FOR LIGHT FOG/MIST INSTEAD. HAVE
OPTED TO FOLLOW THE GFS/ECMWF AND THE POTENTIAL FOR SOME DRIZZLE OR
VERY LIGHT RAIN POSSIBLE IN OUR NORTHEAST CORNER OVERNIGHT. LOWER
VISIBILITIES OR MIST WOULD BE REASONABLE IN THIS AREA AS WELL...BUT
DO NOT THINK THE FOG WILL BE DENSE ENOUGH TO MENTION IN THE GRIDS.
TEMPERATURES WILL BE QUITE MILD OVERNIGHT IN THE 40S.
SATURDAY HAS THE POTENTIAL FOR BEING A VERY MILD DAY...PARTICULARLY
ACROSS OUR EASTERN HALF. THE SURFACE LOW GRADUALLY LIFTS NORTH
NORTHEAST THROUGH THE CENTER OF THE CWA INTO SOUTHWEST MINNESOTA.
IT DOES LOOK LIKE THE STRATUS WILL BEGIN TO BREAK EARLY IN THE DAY
ACROSS OUR EAST AS THE WARM FRONT LIFTS NORTH AND SOUTHERLY FLOW
TAKES OVER. COULD SEE SOME WEAK MID LEVEL INSTABILITY IN THIS WARM
SECTOR IN THE AFTERNOON AND EVENING ACROSS NORTHWEST IOWA WHICH
WOULD BRING AN ISOLATED THREAT FOR SOME THUNDERSTORMS IN ADDITION TO
THE RAIN SHOWERS WHICH SHOULD BEGIN WORKING INTO THE AREA. THE COLD
FRONT FINALLY KICKS THROUGH OUR EASTERN HALF BY LATE SATURDAY
EVENING...WITH THE STRATIFORM PRECIPITATION SPREADING THROUGH THE
REMAINDER OF THE FORECAST AREA BEHIND IT. MUCH COLDER AIR WILL
QUICKLY ARRIVE OVERNIGHT...TRANSITIONING THE RAIN TO A MIX AND THEN
ENTIRELY SNOW BY DAYBREAK.
FOR EARLY SUNDAY...THE LINGERING MID LEVEL EXITS TO OUR EAST WITH
COOLER AND DRIER AIR WORKING INTO THE REGION. THE NAM IS THE FASTEST
IN EXITING THE WAVE WITH THE BULK OF THE EVENT OVER LATE SUNDAY
NIGHT...WHILE THE GFS AND ECMWF SUGGEST A LINGERING BAND OF LIGHT
SNOW OVER THE FORECAST AREA INTO MID DAY. THE BULK OF THE SNOW WILL
BE OVER AT THIS POINT...BUT HAVE HELD ONTO A CHANCE FOR THE MORNING.
THE HIGHEST SNOWFALL AMOUNTS ARE EXPECTED WEST OF THE JAMES RIVER
WHERE 2 TO 3 INCHES ARE EXPECTED...WHILE NORTHWEST IOWA CAN EXPECT A
HALF INCH OR LESS. VERY BRISK NORTHWEST WINDS WILL COMBINE WITH
HIGHS ONLY TOPPING OUT IN THE MID 20S TO MID 30S.
IN THE EXTENDED...QUIETER WEATHER IS ON TAP EARLY NEXT WEEK INTO MID
WEEK AS THE PATTERN TRANSITIONS INTO A MORE ZONAL FLOW. HIGHS ON
MONDAY WILL REMAIN COLD IN THE UPPER 20S TO LOWER 30S...THEN
GRADUALLY MODERATE INTO THE 40S BY MID WEEK. DID DROP LOWS A FEW
DEGREES BELOW THE ALLBLEND ON SUNDAY NIGHT...BUT SOME LINGERING
WINDS WOULD LIKELY PREVENT TEMPERATURES FROM REALLY DROPPING OFF.
LOWS WILL BE IN THE TEENS SUNDAY NIGHT AND MONDAY NIGHT.
&&
.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
550 PM CST THU NOV 8 2012
.DISCUSSION.../ISSUED AT 356 PM CST/
FRONTAL BOUNDARY WILL CONTINUE TO WORK ITS WAY SOUTHEAST ACROSS THE
CWA THIS AFTERNOON AND EVENING. MAIN FORECAST ISSUE TONIGHT INTO
TOMORROW WILL BE CLOUD COVER AND TEMPERATURES. STRATUS DECK
ASSOCIATED WITH THE LOW LEVEL COLD AIR ADVECTION PUSH IS CURRENTLY
MOVING SOUTH INTO NORTHERN SOUTH DAKOTA. MODELS HANDLE THIS FEATURE
DIFFERENTLY. LOOKS LIKE THE NAM IS DECOUPLING THE BOUNDARY LAYER TOO
MUCH TONIGHT...WHICH ACTS TO KEEP THE STRATUS AT BAY. FEEL LIKE
SOMETHING CLOSER TO THE RAP SOLUTION IS MOST LIKELY...WHERE THE COLD
AIR ADVECTION KEEPS THE BOUNDARY LAYER MIXED ENOUGH TO KEEP THE
STRATUS LOCKED IN AND SPREADING SOUTH. COULD EVEN SEE SOME SPOTTY
DRIZZLE IN THE EASTERLY UPSLOPE LOCATIONS OF SOUTHWEST MINNESOTA.
THUS WILL LEAN TOWARDS THIS SOLUTION WITH CLOUDS INCREASING FROM
NORTH TO SOUTH TONIGHT. LOWS MAINLY IN THE 30S...WITH THE CLOUDS AND
BREEZE PREVENTING TEMPS FROM FALLING TOO FAR.
ON FRIDAY...LOW STRATUS WILL BEGIN TO ERODE FROM SOUTH TO NORTH.
HOWEVER AT THE SAME TIME...SOUTHEASTERLY WINDS WILL ADVECT IN
ADDITIONAL MOISTURE AROUND 850 MB...ALLOWING ANOTHER STRATUS DECK TO
QUICKLY FORM. THUS THINK MUCH OF THE AREA STAYS CLOUDY THROUGH THE
DAY...WITH SOUTHERN AREAS HAVING THE BEST CHANCE OF SEEING A BIT OF
MORNING SUN. MOISTURE WILL CONTINUE TO DEEPEN THROUGH THE DAY...WITH
PORTIONS OF SOUTHWEST MINNESOTA AND NORTHWEST IOWA POSSIBLY SEEING
SOME DRIZZLE BY MID AFTERNOON AS WE SEE WEAK LIFT IN THE NEARLY
SATURATED 0-1 KM LAYER. FORECAST CONFIDENCE IS OVERALL PRETTY LOW ON
FRIDAY. THE NAM IS A LOT SLOWER THAN THE GFS WITH STRATUS
FORMATION...WITH THE GFS THE FASTEST. THE FORECAST FOLLOWS CLOSEST
TO THE GFS SOLUTION...WHICH APPEARS TO BE HANDLING THINGS BEST AT
THE CURRENT TIME. THUS WITH THE CLOUDS AROUND...LOWERED HIGHS A FEW
DEGREES FOR TOMORROW...GENERALLY MID TO UPPER 40S NORTH TO MID 50S
SOUTHEAST. IF A SOLUTION CLOSER TO THE NAM PANS OUT RESULTING IN A
LONGER PERIOD OF SUN...HIGHS WILL BE A GOOD 5 DEGREES WARMER...AND
IF THE CLOUDS STAY LOCKED IN EVEN MORE THAN EXPECTED...HIGHS WOULD
BE A FEW DEGREES COOLER THAN CURRENT FORECAST. /CHENARD
COMPLICATED FORECAST ANTICIPATED FOR THE WEEKEND WITH THE WELL
ADVERTISED SURFACE LOW AND BROAD SURFACE TROUGH TRACKING THROUGH THE
AREA. FOR FRIDAY NIGHT...LOW STRATUS WILL REMAIN A CONCERN WITH ALL
MODELS KEEPING A LOW CLOUD DECK IN PLACE OVERNIGHT. THE GFS AND
ECMWF CONTINUE TO INDICATE A DEEPER MOIST LAYER THAN THE NAM...WHICH
POINTS TO A GREATER POTENTIAL FOR LIGHT FOG/MIST INSTEAD. HAVE
OPTED TO FOLLOW THE GFS/ECMWF AND THE POTENTIAL FOR SOME DRIZZLE OR
VERY LIGHT RAIN POSSIBLE IN OUR NORTHEAST CORNER OVERNIGHT. LOWER
VISIBILITIES OR MIST WOULD BE REASONABLE IN THIS AREA AS WELL...BUT
DO NOT THINK THE FOG WILL BE DENSE ENOUGH TO MENTION IN THE GRIDS.
TEMPERATURES WILL BE QUITE MILD OVERNIGHT IN THE 40S.
SATURDAY HAS THE POTENTIAL FOR BEING A VERY MILD DAY...PARTICULARLY
ACROSS OUR EASTERN HALF. THE SURFACE LOW GRADUALLY LIFTS NORTH
NORTHEAST THROUGH THE CENTER OF THE CWA INTO SOUTHWEST MINNESOTA.
IT DOES LOOK LIKE THE STRATUS WILL BEGIN TO BREAK EARLY IN THE DAY
ACROSS OUR EAST AS THE WARM FRONT LIFTS NORTH AND SOUTHERLY FLOW
TAKES OVER. COULD SEE SOME WEAK MID LEVEL INSTABILITY IN THIS WARM
SECTOR IN THE AFTERNOON AND EVENING ACROSS NORTHWEST IOWA WHICH
WOULD BRING AN ISOLATED THREAT FOR SOME THUNDERSTORMS IN ADDITION TO
THE RAIN SHOWERS WHICH SHOULD BEGIN WORKING INTO THE AREA. THE COLD
FRONT FINALLY KICKS THROUGH OUR EASTERN HALF BY LATE SATURDAY
EVENING...WITH THE STRATIFORM PRECIPITATION SPREADING THROUGH THE
REMAINDER OF THE FORECAST AREA BEHIND IT. MUCH COLDER AIR WILL
QUICKLY ARRIVE OVERNIGHT...TRANSITIONING THE RAIN TO A MIX AND THEN
ENTIRELY SNOW BY DAYBREAK.
FOR EARLY SUNDAY...THE LINGERING MID LEVEL EXITS TO OUR EAST WITH
COOLER AND DRIER AIR WORKING INTO THE REGION. THE NAM IS THE FASTEST
IN EXITING THE WAVE WITH THE BULK OF THE EVENT OVER LATE SUNDAY
NIGHT...WHILE THE GFS AND ECMWF SUGGEST A LINGERING BAND OF LIGHT
SNOW OVER THE FORECAST AREA INTO MID DAY. THE BULK OF THE SNOW WILL
BE OVER AT THIS POINT...BUT HAVE HELD ONTO A CHANCE FOR THE MORNING.
THE HIGHEST SNOWFALL AMOUNTS ARE EXPECTED WEST OF THE JAMES RIVER
WHERE 2 TO 3 INCHES ARE EXPECTED...WHILE NORTHWEST IOWA CAN EXPECT A
HALF INCH OR LESS. VERY BRISK NORTHWEST WINDS WILL COMBINE WITH
HIGHS ONLY TOPPING OUT IN THE MID 20S TO MID 30S.
IN THE EXTENDED...QUIETER WEATHER IS ON TAP EARLY NEXT WEEK INTO MID
WEEK AS THE PATTERN TRANSITIONS INTO A MORE ZONAL FLOW. HIGHS ON
MONDAY WILL REMAIN COLD IN THE UPPER 20S TO LOWER 30S...THEN
GRADUALLY MODERATE INTO THE 40S BY MID WEEK. DID DROP LOWS A FEW
DEGREES BELOW THE ALLBLEND ON SUNDAY NIGHT...BUT SOME LINGERING
WINDS WOULD LIKELY PREVENT TEMPERATURES FROM REALLY DROPPING OFF.
LOWS WILL BE IN THE TEENS SUNDAY NIGHT AND MONDAY NIGHT.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
A BROAD AREA OF STRATUS REMAINS POISED TO PUSH SOUTHWARD INTO OUR
AREA THROUGH THE OVERNIGHT HOURS...AND HAS ALREADY MOVED INTO KHON
AT THIS TIME. CONFIDENCE IS SOMEWHAT LOW IN REGARD TO HOW FAR SOUTH
THE STRATUS WILL MAKE IT...WITH MODELS NOT HANDLING IT VERY WELL.
THE RAP MODEL SEEMS TO HAVE THE BEST HANDLE ON IT...AND EXPECT THE
LOW CLOUDS TO SPREAD INTO THE INTERSTATE 90 CORRIDOR AFTER 03Z...AND
THEN LESS CONFIDENCE AS TO WHETHER IT WILL MAKE IT ALL THE WAY INTO
KSUX BY THE EARLY MORNING HOURS OF FRIDAY. THE STRATUS DOES APPEAR
TO HANG ON THROUGH THE DAY ON FRIDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
757 PM PST Thu Nov 8 2012
.SYNOPSIS...
The weather pattern in the Pacific Northwest will become more
active tonight when the first of a number of winter weather systems
impacts the region and exits early Saturday Morning. The remainder
of the weekend may remain precipitation free until yet another low
pressure system passage brings snow and rain to the region Monday
and Tuesday.
&&
.DISCUSSION...
Update: We`ve been tracking low pressure and the band of precipitation
wrapping around it. Across much of northeast third of Washington
and the Idaho Panhandle, from the higher Palouse through much of
the Spokane area and northern Mountains eastward, temperatures
have been cold enough to support snow or at least a rain/snow mix.
On the West Plains, near our office, we picked up around 0.7
inches of snow on our snowboard since about 4 pm this afternoon.
The center of the developing low is best analyzed around 700mb and,
using IR satellite and RUC guidance, it has been tracking north-
northeast toward the Spokane/Whitman county border. A deformation
axis/700mb theta-e axis wrapped has been lifting in with it and at
of about 03Z (7PM) it wrapped from the central Panhandle, north
and west to near the eastern I-90 corridor. Lift from the
deepening low and parent upper troug, along with the deformation
axis has been helpig to focus moisture and the resultant
precipitation. At the same time, more widely scattered showers are
found on its backside around the Basin. A bit of a dry slot is
coming up from the south, drying out part of the lower Palouse.
The short-range models continue to track to low and the
accompanying deformation axis (which will continue to provide a
focus for precipitation) northward. Guidance suggests the primary
core of the precipitation starting to shift north of the I-90
corridor going through the overnight into Friday morning. This
trend seems valid. Through Friday the deformation axis weakens
near the foothills of the Selkirks/Long Lake area and gradually
starts to track east-southeast by late Friday.
Given this depicted trend and recalling previous events, oftentime
the deformation axis/boundary stalls and provides more focused
band of precipitation within the broader precipiation shield north
of I-90, from the base of the Selirks into areas near and north of
Coeur d`Alene. Given this thinking and the fact thus far models
seem to have underdone the precipitation amounts I went ahead and
raised QPF and accompanying snow amounts slightly. This does not
change the overall highlights in effect, but some areas could see
localized amounts near or over 6 inches. This is primarily focused
across areas along and north of a line from Wellpinit to Colbert
to Hayden and the Rathdrum Prairie. /J. Cote`
&&
.AVIATION...
00Z TAFS: Conditions will deteriorate this evening as a complex
weather system impacts mainly the eastern TAF sites. KMWH/KEAT may
see some -shrasn with cigs arounnd bkn-ovc050 at times. The eastern
TAF sites will be dealing with rain and snow through the night until
approximately mid-day Friday. As we saw at KPUW the precipitation will
begin as rain...but quickly turn to a rain/snow mix...before finally
turning over to all snow near or just after 03z. Prevailing
conditions are expected to drop to IFR at times through the
night...before cigs/vsby improve to MVFR Friday afternoon. Northeast
winds with gusts to 20kts should be expected at KCOE with localized
blowing and drifting snow overnight...otherwise the winds should
remain at or below 10kt. /Tobin
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 28 33 19 31 19 33 / 100 80 20 0 0 10
Coeur d`Alene 29 33 16 30 17 34 / 100 90 30 10 0 10
Pullman 29 33 20 31 18 34 / 80 80 30 10 10 0
Lewiston 33 38 24 35 22 38 / 70 60 20 10 0 0
Colville 28 37 20 35 20 36 / 100 80 10 0 0 10
Sandpoint 26 31 14 29 16 34 / 100 90 20 0 0 10
Kellogg 28 30 17 26 17 30 / 100 100 60 10 0 0
Moses Lake 29 41 22 38 21 38 / 20 20 10 0 0 0
Wenatchee 32 40 24 38 23 38 / 20 20 10 10 0 0
Omak 30 39 22 37 20 38 / 20 30 10 0 0 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 4 PM PST Friday for Central
Panhandle Mountains-Coeur d`Alene Area-Idaho Palouse-
Northern Panhandle.
Winter Weather Advisory until 4 PM PST Friday for Lewis and
Southern Nez Perce Counties.
WA...Winter Weather Advisory until 4 PM PST Friday for Northeast
Mountains-Okanogan Highlands-Spokane Area-Washington
Palouse.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
315 PM CST WED NOV 7 2012
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
314 PM CST WED NOV 7 2012
AT 3 PM...A SURFACE RIDGE WAS LOCATED FROM THE CENTRAL PLAINS TO
NORTH NORTHEAST INTO THE UPPER MISSISSIPPI RIVER VALLEY. ON THE
EASTERN SIDE OF THIS RIDGE...LOW LEVEL MOISTURE /BELOW 900 MB/
REMAINS TRAPPED BELOW A SUBSIDENCE INVERSION. BOTH THE 07.12Z GFS
AND NAM/WRF SUGGEST THAT AS THE WINDS PICK UP ON WESTERN SIDE OF
THIS RIDGE...THE MOISTURE LIFTS AND EVENTUALLY MIXES OUT AS
BECOMES PROGRESSIVELY THINNER. THESE MODELS SHOW THAT THIS WILL
INITIALLY OCCUR ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA THIS
EVENING...AND SPREAD ACROSS WESTERN WISCONSIN AFTER MIDNIGHT.
MEANWHILE THE LATEST RAP IS INSISTENT THAT THESE LOW CLOUDS WILL
PERSIST THROUGH THE NIGHT. WITH THE SATELLITE SHOWING VERY LITTLE
CLOUDS ON THIS ON THE WESTERN SIDE OF THE RIDGE...WENT ALONG WITH
THE GFS AND NAM/WRF. HOWEVER A BIT CONCERNED THAT THAT THE TIME OF
DAY WOULD FAVOR THE RAP SOLUTION. EVENING SHIFT WILL HAVE TO WATCH
THIS CLOSELY. IF THE CLOUDS DO NOT CLEAR...THE LOW TEMPERATURES
WILL BE ABOUT 5 TO 7 DEGREES TOO COLD.
ON THURSDAY AFTERNOON AND NIGHT...THE 07.12Z MODELS ARE IN GOOD
AGREEMENT THAT A PACIFIC COLD FRONT WILL MOVE EAST THROUGH THE
FORECAST AREA. WITH THE SURFACE LOW MOVING THROUGH ONTARIO AND DRY
AIR /290-300K CONDENSATION DEFICITS GREATER THAN 100 MB/ BEING
ADVECTED OFF OF THE CENTRAL PLAINS AHEAD OF THIS SYSTEM...NOT
EXPECTING TOO MUCH CLOUDS OR PRECIPITATION FROM THIS FRONT.
ON FRIDAY AFTERNOON AND NIGHT...THE MODELS ARE IN GOOD AGREEMENT
THAT A SHORT WAVE TROUGH WILL EJECT OUT OF WESTERN UNITED STATES
LONG WAVE TROUGH. AS THIS WAVES APPROACHES WEAK TO MODERATE
290-300K ISENTROPIC LIFT DEVELOPS OVER THE AREA. THE CONDENSATION
DEFICITS SLOWLY DROP FROM OVER 100 MB ON FRIDAY AFTERNOON TO 20 TO
50 MBS BY SATURDAY MORNING. IN ADDITION...MODERATE 850 MB
TRANSPORT WILL BE DEVELOPING ACROSS THE AREA ON FRIDAY NIGHT. THE
NAM/WRF IS THE SLOWEST AT SATURATING THE ATMOSPHERIC COLUMN. AS A
RESULT...IT DOES NOT GENERATE ANY PRECIPITATION UNTIL IT GETS OVER
NORTHERN MINNESOTA AND FAR NORTHERN WISCONSIN. MEANWHILE THE
GEM...GFS...AND ECMWF HAS THE PRECIPITATION DEVELOPING OVER OUR
AREA. SINCE THE RUN TO RUN VARIABILITY HAS REMAINED INCONSISTENT...
KEPT PRECIPITATION CHANCES IN THE 20 TO 40 PERCENT RANGE. WITH
BOTH THE ECMWF AND NAM/WRF SUGGESTING MLCAPES WILL UP TO 400 J/KG
ALONG AND NORTH OF THE WARM FRONT AFTER MIDNIGHT...ADDED ISOLATED
THUNDERSTORMS TO THE FORECAST.
.LONG TERM...SATURDAY THROUGH WEDNESDAY
314 PM CST WED NOV 7 2012
ON SATURDAY...THE 07.12Z MODELS ARE IN GOOD AGREEMENT THAT THE
AREA WILL ENTER THE WARM SECTOR OF THE LOW PRESSURE SYSTEM. WHILE
THIS IS THE CASE...THEY DO DIFFER ON THE STRENGTH OF THE CAP. THE
NAM/WRF AND GEM HAVE THE STRONGEST CAP...THUS...NO PRECIPITATION.
MEANWHILE THE GFS AND ECMWF SHOW A WEAKER CAP WHICH ALLOWS FOR
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TO CONTINUE
THROUGHPUT THE DAY. SINCE THE MODELS HAVE VERY CONSISTENT WITH
THIS TIME PERIOD...JUST KEPT THE PRECIPITATION CHANCES IN THE 20
TO 40 PERCENT RANGE. THIS PRECIPITATION ALSO AFFECTS THE AMOUNT OF
INSTABILITY THAT CAN DEVELOP AHEAD OF THE APPROACHING COLD FRONT.
WITH NO PRECIPITATION...THE MLCAPES CLIMB TO AROUND 600 J/KG IN
THE NAM/WRF. MEANWHILE THE PRECIPITATION THE GFS AND ECMWF LIMITS
THE MLCAPES TO LESS THAN 300 J/KG. THE 0-6 KM SHEAR IS FAVORABLE
IN ALL 3 MODELS FOR MINI SUPERCELL DEVELOPMENT. HOWEVER A
MAJORITY OF THIS SHEAR IS LOCATED IN THE 0-1 KM LAYER. IF THE
THUNDERSTORMS DO NOT BECOME SURFACE BASED...THESE STORMS WILL ONLY
HAVE LESS THAN 20 KNOTS OF SHEAR TO WORK WITH AND AS A RESULT THEY
WOULD NOT HAVE ADEQUATE SHEAR TO ORGANIZE THEMSELVES INTO MINI
SUPERCELLS.
THE OTHER FORECAST CHALLENGE ON SATURDAY IS HOW WARM THE AREA WILL GET.
850 MB STANDARDIZED ANOMALIES ARE 1 TO 1.5 STANDARD DEVIATIONS ABOVE
NORMAL. THE NAM/WRF HAS LITTLE CLOUDS IN THE WARM SECTOR WHICH
ALLOWS THE HIGH TEMPERATURES TO RANGE FROM THE LOWER 60S TO LOWER
70S. MEANWHILE THE ECMWF HAS MORE CLOUD COVER AND ITS TEMPERATURES
RANGE FROM THE LOWER 50S TO LOWER 70S. WITH SUCH UNCERTAINTY
STAYED WITH THE ALL BLEND WHICH HAS HIGH TEMPERATURES RANGING FROM
THE MID 50S TO UPPER 60S.
FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE MODELS ARE IN GOOD
AGREEMENT THAT A STRONG COLD FRONT WILL MOVE THROUGH THE REGION.
STRONG PV ADVECTION AND FRONTOGENESIS WILL RESULT IN WIDESPREAD
SHOWERS AND ISOLATED THUNDERSTORMS TO DEVELOP ACROSS THE AREA.
WHILE THIS HAS BEEN A CONSISTENT SIGNAL...THE MODELS HAVE SHOWN
SOME TIMING DIFFERENCES OVER THE PAST COUPLE OF DAYS...THUS...KEPT
PRECIPITATION PROBABILITIES IN THE 55 TO 74 RANGE. TEMPERATURES IN
THE WAKE OF THIS FRONT WILL QUICKLY FALL INTO THE 30S. SOUNDINGS
ALOFT SUGGEST THAT THERE WILL BE SOME ICE CRYSTALS BEING
INTRODUCED FROM ALOFT...THUS...SOME SNOW STILL LOOKS POSSIBLE FROM
SUNDAY AFTERNOON INTO SUNDAY NIGHT. ANY ACCUMULATIONS WILL BE
HIGHLY DEPENDENT UPON HOW FAST THIS RAIN TO SNOW TRANSITION
OCCURS.
FROM LATE SUNDAY NIGHT INTO MONDAY...IT APPEARS THAT THE 07.12Z MODELS
ARE MUCH FASTER THAN THEIR PREDECESSORS AT MOVING THE
PRECIPITATION OUT OF THE AREA. WANTED TO FOLLOW THEM...BUT COULD
NOT GET ENOUGH CONSENSUS TO GO AWAY FROM THE ALL BLEND MODEL.
&&
.AVIATION...THROUGH 18Z THURSDAY
1152 AM CST WED NOV 7 2012
MAIN AVIATION CONCERNS FOR THIS TIME PERIOD IS MVFR CONDITIONS AT
BOTH RST AND LSE TAF SITES THROUGH 06Z THURSDAY. LATEST 17Z SURFACE
ANALYSIS SHOWS HIGH PRESSURE OVER EASTERN NEBRASKA AND EASTERN
KANSAS AND LATEST VISIBLE SATELLITE IMAGERY INDICATING
STRATOCUMULUS CLOUD DECK OVER MUCH OF WISCONSIN...EASTERN
MINNESOTA AND EASTERN IOWA. LATEST METARS INDICATE CEILING HEIGHTS
SCATTERED TO BROKEN AT 1500 TO 3000 FEET AND BROKEN/OVERCAST LAYER AT OR
ABOVE 3500 FEET ACROSS THE AREA. WITH REGION REMAINING UNDER THE
INFLUENCE OF NORTHERLY FLOW ALOFT AND STRONG INVERSION IN PLACE THIS
AFTERNOON...STRATOCUMULUS DECK WILL HAVE A HARD TIME ERODING.
LATEST 07.12Z NAM BUFKIT SOUNDINGS DO INDICATE CEILINGS LIFTING UP
ABOVE MVFR CONDITIONS AT BOTH TAF SITES THIS AFTERNOON. HAVE
INTRODUCED SCATTERED DECK OF CLOUDS AT 2000-2500 FEET AND A
BROKEN/OVERCAST LAYER AT 4000 FEET. SURFACE RIDGE BUILDS INTO
THE AREA AND OVER THE OHIO RIVER VALLEY THIS EVENING/TONIGHT...ON
THE BACKSIDE OF SURFACE RIDGE SOUTHERLY WIND FLOW WILL ALLOW STRATOCUMULUS
DECK TO ERODE BY 06Z THURSDAY AT BOTH RST AND LSE TAF SITES.
PRESSURE GRADIENT TIGHTENS OVER THE REGION BY 12Z THURSDAY AND
WILL INCREASE SOUTHERLY WINDS AT BOTH TAF SITES BY 13Z. HAVE
INTRODUCED SUSTAINED SOUTHERLY WINDS OF 10 TO 15 KNOTS BY 12Z-13Z
AT RST AND LSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
200 PM CST WED NOV 7 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...DTJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
329 AM CST WED NOV 7 2012
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
329 AM CST WED NOV 7 2012
MAIN FORECAST CONCERNS THIS PACKAGE...-RA/-DZ CHANCES FRI NIGHT...
CLOUDS AND TEMPERATURES THROUGH THE PERIOD.
06Z DATA ANALYSIS HAD A WEAK AREA OF LOW PRESSURE OVER IL WITH
TROUGHING TO THE NORTH INTO WESTERN ONT. FOG PRODUCT IMAGERY AND SFC
OBS SHOWED A RATHER SOLID STRATUS SHIELD OVER MOST OF THE UPPER
MIDWEST EARLY THIS MORNING...WITH LOWER LEVEL MOISTURE TRAPPED UNDER
AND INVERSION NEAR 775MB. TEMPS RATHER UNIFORM UNDER THE CLOUD DECK
EARLY THIS MORNING. MODELS DOING A DECENT JOB WITH THE CLOUDS
EARLY THIS MORNING AS THE WEST EDGE OF THE CLOUD SHIELD LINES UP
QUITE WELL WITH THE 925-850MB 70-80 PERCENT MEAN RH. FOG WAS COMMON
ACROSS WI/IL...ALONG/EAST OF THE SFC TROUGH AXIS WHERE WINDS
REMAINED LIGHT/VARIABLE.
07.00Z MODEL INITIALIZATIONS QUITE CONSISTENT AND SOLUTIONS ARE VERY
SIMILAR FOR TODAY THRU FRI NIGHT. BIGGEST DIFFERENCES LOOK TO BE
WITH PRECIP CHANCES BY FRI NIGHT. DPROG/DT OF 500MB HGTS AT 07.00Z
SHOWED MODEL RUNS OF 05.00Z AND 06.00Z VERIFIED REASONABLY WELL
ACROSS NOAM/EASTERN PAC WITH BETTER RUN-TO-RUN CONSISTENCY TO GFS.
MODELS OFFER A GOOD CONSENSUS AND GOOD RUN-TO-RUN CONSISTENCY FOR
TODAY THRU FRI NIGHT...BUT FOR THE 05.00Z NAM RUN. THIS WITH A
RATHER AMPLIFIED/PROGRESSIVE FLOW PATTERN AND LONGWAVE TROUGHING
MOVING INTO THE WESTERN CONUS. CHECK OF OBS VS. MODEL DATA AT 06Z
SHOWED ALL TO BE REASONABLE WITH THE SFC MASS FIELDS OVER THE
CENTRAL CONUS AND AGAIN HANDLING THE REGIONAL STRATUS DECK WELL. PER
WV IMAGERY ALL APPEARED SIMILAR AND GOOD WITH THE SHORTWAVE DETAILS
OVER NOAM. A MODEL BLEND LOOKED BEST WITH THE 00-06Z PRECIP ACROSS
THE MID/ UPPER MS VALLEY. NO CLEAR MODEL FAVORITE AND WITH MODELS
OFFERING A RATHER TIGHT CONSENSUS THRU FRI NIGHT...AGAIN FAVORED A
MODEL/ ENSEMBLE CONSENSUS. SHORT-TERM FCST CONFIDENCE GOOD THIS
CYCLE.
IN THE SHORT TERM...THE STRATUS CLOUDS AND THEIR DEPARTURE WILL BE
PROBLEMATIC TODAY/TONIGHT. CLOUDS HANGING TOUGH OVER THE REGION
EARLY THIS MORNING. PER LAPS/MODEL SOUNDINGS MOISTURE LOOKS TO
BE A FEW THOUSAND FT DEEP IN/UNDER A STRENGTHENING SUBSIDENCE
INVERSION AROUND 775MB. SUBSIDENCE INVERSION CONTINUES TO STRENGTHEN
AND LOWER TODAY WITH GRADIENT WIND FLOW IN/UNDER THE INVERSION
QUITE LIGHT...WHICH DOES NOT HELP THE PROSPECTS OF SCOURING OUT THE
STRATUS CLOUDS. INCREASED/LINGERED MORE CLOUDS IN THE GRIDS TODAY...
AND TRENDED SOME OF THIS INTO TONIGHT. 925-850MB GRADIENT FLOW
INCREASES FROM THE SOUTH/SOUTHWEST TONIGHT AS THE LOW LEVEL RIDGE
AXIS MOVES EAST AND TROUGHING DEVELOPS IN THE CENTRAL/NORTHERN
PLAINS. CONTINUED THE TREND OF DECREASING/CLEARING LOW CLOUDS
TONIGHT BUT MODEL SOUNDINGS SHOWING MOISTURE ABOVE 500MB AHEAD OF
THE TROUGHING MOVING ONTO THE WEST COAST TO SPREAD ACROSS THE AREA
LATER TONIGHT/THU MORNING.
BEST SHOT AT SOME SUNSHINE THE REST OF THIS WEEK APPEARS TO BE THU
AFTERNOON. THIS IN A BREAK IN THE HIGHER LEVEL MOISTURE STREAMING
EAST ACROSS THE REGION AND BEFORE THE LOWER LEVEL MOISTURE SURGING
NORTH AHEAD OF THE DEEPENING PLAINS TROUGH BEGINS TO ARRIVE. ONE
FRONTAL BOUNDARY GETS DRAGGED INTO THE AREA BY A SHORTWAVE/LOW
PASSING ACROSS SOUTHERN CAN THU NIGH/FRI. THIS WHILE FALLING
PRESSURES IN THE CENTRAL PLAINS AND INCREASING SOUTHERN FLOW THRU
THE MID MS VALLEY DEVELOP A WARM FRONTAL BOUNDARY ACROSS SOUTHERN
IA/NORTHERN IL FRI. THESE 2 BOUNDARIES AND RESULTING TROUGHING
ACROSS IA INTO WI WILL BE THE FOCUS FOR LIFTING OF THE INCREASING
GULF MOISTURE LIFTING NORTHWARD. MODEL SOUNDINGS SHOW THIS MOISTURE
TO BE TRAPPED IN/UNDER ANOTHER INVERSION FRI/FRI NIGHT. LEFT FRI DRY
WITH LIMITED DEPTH OF SATURATION...THE INVERSION AND BULK OF 850-
700MB WARM ADVECTION LOOKING TO GO INTO WARMING.
DEPTH OF SATURATION INCREASES FRI NIGHT...UP TO A COUPLE KILOMETERS
DEEP UNDER THE INVERSION. THIS WITH WEAK WARM ADVECTION/LIFT IN THE
SUB-INVERSION LAYER AND INCREASING WIND SHEAR NEAR THE INVERSION
LAYER...AND THE WARM FRONTAL BOUNDARY/TROUGH LIFTING NORTH INTO THE
AREA. ALL THIS APPEARS FAVORABLE FOR -DZ/VERY LIGHT -RA FRI NIGHT.
GIVEN THE CAPPING NEAR 750MB AND LITTLE IN THE WAY OF FORCING/LIFT
SIGNALS OUTSIDE OF THAT BELOW THE INVERSION...LEFT -DZ/-RA CHANCES
FRI NIGHT MOSTLY IN THE 20 TO 35 PERCENT RANGE.
CLOUDS WILL IMPACT HIGHS/LOWS THROUGH THE PERIOD...HOWEVER BLEND OF
THE NUMERICAL TEMP GUIDANCE LOOKS TO HAVE THIS WELL TRENDED. DID NOT
STRAY FAR FROM THE MODEL/ENSEMBLE BLEND FOR NOW GIVEN SOME
UNCERTAINTIES WITH CLOUD COVER TONIGHT THRU FRI. A SHORT PERIOD OF
CLEAR SKIES AT NIGHT OR SUNSHINE DURING THE DAY COULD MAKE A
DIFFERENCE OF 5F OR MORE ON THE LOW OR HIGH TEMPS ANY ONE PERIOD.
.LONG TERM...SATURDAY THROUGH TUESDAY
1029 AM +ST WED NOV 7 2012
07.00Z MEDIUM RANGE MODELS REMAIN IN GOOD AGREEMENT AS THE WESTERN
CONUS TROUGH MOVES EAST TOWARD AND ACROSS THE UPPER MIDWEST IN THE
DAY 4-7 PERIOD. FCST CONFIDENCE FOR SAT-TUE REMAINS AVERAGE TO
GOOD. THE TROUGH BEGINS TO EJECT INTO THE PLAINS SAT WITH A RATHER
STRONG SFC LOW LIFTING INTO MN. SOME DETAIL DIFFERENCES AS EXPECTED
BUT THE AREA ENDS UP IN THE WARM SECTOR SAT. MAIN FORCING/LIFT
REMAIN WEST/NORTH OF THE FCST AREA SAT BUT A 20-35 PERCENT -SHRA
CHANCE PER THE MODEL CONSENSUS NOT UNREASONABLE. MODELS CONTINUE TO
INDICATE WEAK CAPE OVER THE AREA SAT SO CANNOT RULE OUT TSRA EITHER.
BIGGER QUESTION SAT IS EXTENT OF CLOUD COVER AND IMPACTS ON HIGH
TEMPERATURES ON SAT. WITH SATURATION INDICATED IN THE SFC-900MB
LAYER BELOW A MDT/STRONG INVERSION WOULD APPEAR AREA MAY REMAIN
UNDER A LOW STRATUS DECK. STAYED WITH A MOSTLY CLOUD FCST ON SAT AND
HIGHS IN THE 60S. WITH ANY AMOUNT OF SUNSHINE THOUGH...HIGHS COULD
TOP 70...ESPECIALLY ACROSS NORTHEAST IA.
STRONG COLD FRONT SLIDES INTO/ACROSS THE AREA SAT NIGHT/EARLY SUN AS
THE LOW LIFT TO NORTH OF LS SUPERIOR. DEEP SATURATION AND DEEP
LAYERED FORCING/LIFT MOVE ACROSS WITH THE FRONT...ESPECIALLY LATER
SAT NIGHT/SUN. SOME CAPE TO 250 J/KG CONTINUES TO BE INDICATED SAT
NIGHT AS WELL. WITH INCREASING CONFIDENCE/CONSISTENCY OF THE MODEL
SIGNAL...SHRA CHANCES CONTINUE TO INCREASE FOR SAT NIGHT/SUN. SMALL
TSRA CHANCE ALSO REMAINS SAT NIGHT. BIGGEST UNCERTAINTY HERE IS
WHERE THE HEAVIER RAINS MAY FALL...AS APPEARS 1 TO 2 INCHES OF
RAIN IS POSSIBLE FOR PARTS OF THE AREA SAT NIGHT/SUN.
POST-FRONTAL COLD AIR SPREAD ACROSS THE AREA LATE SUN/SUN NIGHT.
QUESTION REMAINS WILL THE COLD AIR ARRIVE BEFORE THE LIFT/DEEPER
MOISTURE EXIT...ALLOWING FOR THE PRECIP TO MIX WITH/CHANGE TO SNOW
BEFORE ENDING/MOVING OUT SUN NIGHT. FOR NOW STAYED WITH THE MODEL/
ENSEMBLE CONSENSUS FOR A CHANCE OF -SN AS THE PRECIP ENDS/MOVES OUT
SUN NIGHT. MON/TUE TREND DRY/COLD AS THE MID LEVEL TROUGH AXIS
PASSES AND CANADIAN HIGH PRESSURE SETTLES SOUTH/EAST ACROSS THE
REGION. MODEL/ENSEMBLE CONSENSUS HIGHS/LOWS FOR SAT THRU APPEAR WELL
TRENDED AT THIS TIME WITH NO CHANGES MADE.
&&
.AVIATION...THROUGH 06Z THURSDAY
1132 PM CST TUE NOV 6 2012
BIGGEST FORECAST CONCERN IS ON CEILINGS HEIGHTS AND IF CLOUDS
CLEAR DURING THIS TAF PERIOD. FRONTAL BOUNDARY THROUGH BOTH TAF
SITES...WITH NORTHWEST WINDS NOW BEING REPORTED. LARGE STRATUS
DECK SEEN ALL THE WAY BACK TO THE DAKOTAS/MINNESOTA BORDER.
CEILINGS ARE PRIMARILY IN THE MVFR/VFR CATEGORY. MODEL SOUNDINGS
FROM THE 07.03Z RAP AND 07.00Z NAM SHOWING LOWEST LAYERS TO REMAIN
SATURATED AND EXPECT THESE MAINLY MVFR CEILINGS TO PERSIST INTO
THE AFTERNOON HOURS BEFORE RISING INTO THE VFR CATEGORY. NAM HAS
COME IN MORE PESSIMISTIC IN CLEARING THE SKIES...WITH 90 PERCENT
925MB RELATIVE HUMIDITY FROM THE MISSISSIPPI RIVER EASTWARD ALL
THE WAY THROUGH 06Z. THUS DID SLOW THE CLEARING AT KRST UNTIL
03Z AND KEPT A BROKEN VFR DECK AT KLSE THROUGH 06Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
329 AM CST WED NOV 7 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION.....RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1132 PM CST TUE NOV 6 2012
.SHORT TERM...TONIGHT THROUGH FRIDAY
238 PM CST TUE NOV 6 2012
THE MAIN FOCUS THROUGH FRIDAY IS WITH HOW LONG THE PRECIPITATION AND
CLOUD COVER HOLDS ON FOR INTO WEDNESDAY ALONG WHERE A COLD FRONT
WILL END UP THURSDAY INTO FRIDAY.
CURRENTLY...A BAND OF RAIN AND SNOW WILL CONTINUE TO TRACK TO THE
EAST TONIGHT AHEAD OF WHAT APPEARS TO BE A WARM FRONT RATHER THAN
A COLD FRONT EXTENDING SOUTH ALONG THE MISSISSIPPI RIVER. A
SURFACE LOW NEAR DULUTH WILL QUICKLY DROP TO THE SOUTHEAST WITH A
RIDGE OF HIGH PRESSURE MOVING INTO THE CENTRAL PLAINS. IN THE
UPPER LEVELS...AN AMPLIFIED PATTERN IS TAKING SHAPE WITH BROAD
TROUGHING ALONG THE ATLANTIC COAST AND RIDGING ACROSS THE ROCKIES.
THIS LEAVES THE UPPER MISSISSIPPI RIVER VALLEY IN NORTHWESTERLY
FLOW ALOFT WITH COOL AIR COMING INTO THE REGION FROM CANADA.
AS THE LOW DROPS DOWN TONIGHT IT WILL KEEP SOME HIGH AMOUNTS OF
MOISTURE LOCKED IN THE LOW LEVELS WITH STEEP SURFACE TO 800MB
LAPSE RATES BASED ON 06.12Z NAM/GFS AND 06.18Z RAP SOUNDINGS. WITH
ENOUGH LOW LEVEL LIFT PERSISTING THROUGH THE NIGHT AND THE DEEP
LOW LEVEL MOISTURE EXTENDING FROM NEAR THE SURFACE UP INTO THE
-10C RANGE AROUND 10KFT...SOME RAIN AND SNOW SHOWERS WILL DEVELOP/MOVE
IN WITH THE LOW THIS EVENING. THE DEPTH OF THE MOISTURE AND LIFT
SLOWLY DECREASE OVERNIGHT AS THE SYSTEM MOVES INTO THE OHIO RIVER
VALLEY WHICH MEANS THAT ICE WILL STOP BEING GENERATED AND THE
THERMAL PROFILE BECOMES MORE FAVORABLE FOR DRIZZLE. ANY LOW LEVEL
OMEGA APPEARS TO BE OUT OF THE REGION BY AROUND 12Z TOMORROW
MORNING...SO THE DRIZZLE SHOULD END BY THEN.
CONFIDENCE IS NOT HIGH WITH HOW LONG THE CLOUD COVER WILL HOLD ON
FOR...BUT HAVE GONE THE PESSIMISTIC ROUTE UNTIL THE RIDGE GETS IN
TOMORROW AFTERNOON. 06.12Z NAM/GFS SOUNDINGS DO INDICATE SOME
MOISTURE REMAINING TRAPPED UNDER A SINKING INVERSION THAT DROPS TO
AROUND 4KFT BY TOMORROW AFTERNOON. DUE TO THIS CLOUD COVER...HAVE
KEPT OVERNIGHT LOWS UP A BIT ABOVE GUIDANCE AND THEN LOWERED THEM
A FEW DEGREES TOMORROW.
THE FOCUS THEN SHIFTS TO A COLD FRONT THAT WILL DROP DOWN INTO THE
REGION AS A MID LEVEL SHORT WAVE TROUGH SKIRTS THE NORTHERN
PERIPHERY OF THE RIDGE. THE CONSENSUS BETWEEN THE 06.12Z GUIDANCE
IS TO BRING THE FRONT ACROSS CENTRAL WISCONSIN AND IOWA TO A
SURFACE LOW IN EASTERN COLORADO BY FRIDAY MORNING. IT WILL THEN
STALL AND TRANSITION TO BEING A WARM FRONT WITH LOW LEVEL WARM AIR
ADVECTION KICKING IN AS THE LOW EJECTS INTO THE PLAINS. WENT DRY
ON FRIDAY BUT WILL HAVE TO MONITOR AS THE 06.12Z GFS SHOWS ENOUGH
DEPTH TO THE MOISTURE ALONG THE FRONT THAT A FEW SHOWERS OR
DRIZZLE COULD DEVELOP.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
238 PM CST TUE NOV 6 2012
THE MAIN FOCUS FOR NEXT WEEKEND IS WITH THE BROAD TROUGHING ALOFT
THAT BRINGS A DEEPENING SURFACE LOW ACROSS MINNESOTA ON SATURDAY.
PRECIPITATION SHOULD BECOME MORE WIDESPREAD FRIDAY NIGHT AS THE
WARM AIR ADVECTION STRENGTHENS AHEAD OF THE LOW. SHOWERS AND
THUNDERSTORMS WILL DEVELOP AHEAD OF A COLD FRONT IN MINNESOTA ON
SATURDAY WHERE 0-3KM MUCAPE INCREASES TO AROUND 1000 J/KG IN THE
AFTERNOON. IT APPEARS THAT THE BETTER CHANCES FOR ANY SEVERE
WEATHER WILL BE TO THE WEST NEAR THE TRACK OF THE SURFACE LOW AND
AHEAD OF THE COLD FRONT. SOME INSTABILITY HOLDS ON INTO THE
EVENING AND OVERNIGHT...BUT IS RATHER SKINNY AND WEAKENS AS THE
NIGHT PROGRESSES.
AFTER THE FRONT PASSES THROUGH EARLY ON SUNDAY...THE NEXT QUESTION
IS WITH WHETHER OR NOT THE COLD AIR WILL GET IN FAST ENOUGH WITH
THE PRECIPITATION STILL FALLING THAT IT WOULD CHANGE OVER FROM
RAIN TO SNOW. THE 06.12Z GFS IS A BIT FASTER WITH ENDING THE
PRECIPITATION ON SUNDAY WHILE THE 06.12Z ECMWF HOLDS ONTO IT A BIT
LONGER WITH A LOW TO MID LEVEL BAND OF FRONTOGENESIS WHICH COULD
END UP BEING MORE CONDUCIVE TO THE SNOW OCCURRING. TEMPERATURES
WILL PLUMMET SUNDAY THROUGH TUESDAY AS 850MB TEMPERATURES DROP TO
AROUND -12C WHICH WILL HELP TO KEEP TEMPERATURES IN THE 30S FOR
HIGHS AND 20S FOR LOWS.
&&
.AVIATION...THROUGH 06Z THURSDAY
1132 PM CST TUE NOV 6 2012
BIGGEST FORECAST CONCERN IS ON CEILINGS HEIGHTS AND IF CLOUDS
CLEAR DURING THIS TAF PERIOD. FRONTAL BOUNDARY THROUGH BOTH TAF
SITES...WITH NORTHWEST WINDS NOW BEING REPORTED. LARGE STRATUS
DECK SEEN ALL THE WAY BACK TO THE DAKOTAS/MINNESOTA BORDER.
CEILINGS ARE PRIMARILY IN THE MVFR/VFR CATEGORY. MODEL SOUNDINGS
FROM THE 07.03Z RAP AND 07.00Z NAM SHOWING LOWEST LAYERS TO REMAIN
SATURATED AND EXPECT THESE MAINLY MVFR CEILINGS TO PERSIST INTO
THE AFTERNOON HOURS BEFORE RISING INTO THE VFR CATEGORY. NAM HAS
COME IN MORE PESSIMISTIC IN CLEARING THE SKIES...WITH 90 PERCENT
925MB RELATIVE HUMIDITY FROM THE MISSISSIPPI RIVER EASTWARD ALL
THE WAY THROUGH 06Z. THUS DID SLOW THE CLEARING AT KRST UNTIL
03Z AND KEPT A BROKEN VFR DECK AT KLSE THROUGH 06Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
238 PM CST TUE NOV 6 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
345 AM EST FRI NOV 9 2012
.DISCUSSION...
TODAY-TONIGHT...A LARGE H100-H70 HI PRES RIDGE EXTENDING FROM THE
BAY OF CAMPECHE TO THE GREAT LAKES REGION WILL DRIFT E/NE TODAY AS A
SHORT WAVE TROF OFF THE ERN SEABOARD PUSHES INTO THE OPEN ATLC. THU
EVNG RAOB SOUNDINGS SHOW A VERY DRY/STABLE AIRMASS OVERHEAD WITH A
25C SUBSIDENCE INVERSION IN THE H85-H60 LYR ACRS CENTRAL FL...PWAT
VALUES ARND 0.3".
LATEST RAP ANALYSIS SHOWS A TIGHT RH GRADIENT IN THE H100-H85 LYR
EXTENDING FROM THE CAPE TO LAKE OKEECHOBEE...VALUES AOB 35PCT TO THE
NW AND AOA 65PCT TO THE SE. SFC/TRANSPORT WINDS ARE EXPECTED TO VEER
TO THE NE BY MIDDAY AFTN AS THE ANTICYCLONE PUSHES E. HOWEVER...THIS
WILL ONLY BRING THE WINDS INTO PARALLEL ALIGNMENT WITH THE RH
GRADIENT...THUS LIMITING THE POTENTIAL FOR AIRMASS MODIFICATION TO
THE COASTAL COUNTIES. WINDS WILL CONTINUE TO VEER TO THE E/NE
OVERNIGHT WHICH SHOULD PROVIDE ENOUGH WRLY PUSH TO BEGIN MODIFYING
THE DRY AIR OVER THE INTERIOR.
WILL KEEP MOSUNNY SKIES OVER THE INTERIOR THRU THE AFTN...PSUNNY
ALONG THE COAST...PCLDY ACRS THE SRN CWA/MCLR NRN CWA OVERNIGHT. MAX
TEMPS WILL BEGIN TO REBOUND FROM THE RECENT COOL DOWN...THOUGH THE
NRLY WIND COMPONENT WILL MAINTAIN ENOUGH COOL ADVECTION TO KEEP
TEMPS IN THE L/M70S...ARND 5F BLO CLIMO. AS WINDS BECOME MORE NORMAL
TO THE COAST OVERNIGHT...MIN TEMPS ALONG AND E OF THE I-95 CORRIDOR
WILL HOLD IN THE M-U50S...L/M50S OVER THE INTERIOR.
SAT-SUN...RIDGE ALOFT WILL AMPLIFY NEAR THE EAST COAST IN RESPONSE
TO TROF DEEPENING THROUGH THE PLAINS. SURFACE HIGH PRESSURE WILL BE
REINFORCED TO THE NORTH...WITH WINDS VEERING FROM THE NORTHEAST TO
EAST AND PICKING UP A BIT AS IT DOES SO. RIDGE ALOFT AND VEERING LOW
LEVEL FLOW WILL ALLOW TEMPERATURES TO MODERATE WITH HIGHS SATURDAY
MID 70S COAST/UPPER 70S INLAND...AND UPPER 70S COAST/AROUND 80
INLAND ON SUNDAY. OVERNIGHT MINS LOW/MID 50S SAT MORN...RISING TO
UPPER 50S/LOWER 60S INLAND AND VOLUSIA...MID/UPPER 60S SPACE AND
TREASURE COASTS SUNDAY. SHALLOW MOISTURE DEPTH AND PERSISTENCE OF
INVERSION ALOFT EXPECTED TO KEEP POPS BELOW MENTIONABLE VALUES.
MON-THU...SURFACE RIDGE THE NORTH WILL DRIFT EASTWARD OVER THE
ATLANTIC EARLY NEXT WEEK AHEAD OF A FRONT THAT WILL MOVE DOWN THE
PENINSULA IN THE TUE-TUE NIGHT TIME FRAME. WILL KEEP CONTINUITY
INDICATING A LOW RAIN CHANCE WITH THE FRONT. ONLY SLIGHT COOLING
EXPECTED BEHIND THE FRONT BEFORE FLOW QUICKLY VEERS ONSHORE AGAIN
WED INTO THURS.
&&
.AVIATION...THRU 10/12Z...VFR ALL SITES.
&&
.MARINE...TODAY-TONIGHT...HIGH PRES RIDGE OVER THE GOMEX/DEEP SOUTH
WILL GENERATE A MODERATE N/NE BREEZE ACRS THE LCL ATLC THIS AFTN...
BCMG E/NE OVERNIGHT AS THE RIDGE DRIFTS TOWARD THE ERN SEABOARD. THE
NRLY WIND COMPONENT WILL COMBINE WITH THE SRLY COMPONENT OF THE GULF
STREAM TO GENERATE SEAS UP TO 7FT IN THE GULF STREAM. HOWEVER...
LATEST OBS FROM THE LCL DATA BUOY/C-MAN NETWORK SHOW THE THE LCL
PGRAD IS NOT TIGHT ENOUGH GENERATE WINDS ABV 15KTS. WILL EXTEND THE
SCA THRU SUNSET TONIGHT BUT FOR SEAS ONLY...CAUTIONARY STATEMENT
WILL REMAIN IN PLACE FOR THE NEARSHORE WATERS N OF SEBASTIAN INLET.
SAT-WED...FLOW WILL VEER TOWARD THE EAST THIS WEEKEND WITH MODERATE
TO FRESH EASTERLY WINDS INTO MONDAY. WINDS EASING A BIT AND BECOMING
MORE VARIABLE TUE/TUE NIGHT AS FRONT MOVES DOWN THE PENINSULA THEN
ONSHORE WINDS RESUME AGAIN RATHER QUICKLY BEHIND THE FRONT. LONG
PERIOD SWELL WILL ELEVATE SEA HEIGHTS BEYOND WHAT WINDS ALONE WOULD
SUGGEST THROUGH THE END OF THE PERIOD.
&&
.FIRE WEATHER...TODAY-TONIGHT...VERY DRY AIRMASS OVERHEAD WITH 00Z
RAOBS MEASURING PWAT VALUES ARND 0.3" ACRS CENTRAL FL. WHILE THE
BULK OF THE DRY AIR IS LOCATED ABV A VERY STRONG SUBSIDENCE
INVERSION IN THE H90-H60 LYR...DEW POINT DEPRESSIONS BLO H90 ARE ON
THE ORDER OF 10C.
EXPECT TO SEE SFC RH FALL BLO 35PCT ARND MIDDAY WEST OF A LINE FROM
LAKE KISSIMMEE TO LAKE MONROE TO LAKE GEORGE...WITH VALUES FALLING
BLO 30PCT ALONG AND N OF THE I-4 CORRIDOR FOR 4-6HRS. LATEST ERC
VALUES OVER EAST CENTRAL FL AND THE SURROUNDING COUNTIES ARE AOB THE
35 THRESHOLD NECESSARY TO TRIGGER AN RFW...WILL GO WITH A FIRE
DANGER STATEMENT INSTEAD AND HIGHLIGHT IN THE HWO.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 71 53 75 60 / 0 0 0 0
MCO 73 53 78 59 / 0 0 0 0
MLB 72 58 76 66 / 0 0 0 0
VRB 73 58 76 66 / 0 0 10 0
LEE 72 51 77 57 / 0 0 0 0
SFB 73 52 78 59 / 0 0 0 0
ORL 74 53 78 60 / 0 0 0 0
FPR 72 57 76 65 / 0 0 10 0
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 7 PM EST
THIS EVENING FOR COASTAL WATERS FROM SEBASTIAN INLET TO
JUPITER INLET OUT 20 NM-WATERS FROM FLAGLER BEACH TO
VOLUSIA BREVARD COUNTY LINE 20 TO 60 NM OFFSHORE-WATERS
FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM OFFSHORE-
WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET
20 TO 60 NM OFFSHORE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM....GLITTO
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
322 AM EST FRI NOV 9 2012
.SYNOPSIS...
ISSUED AT 322 AM EST FRI NOV 9 2012
A WARM FRONT IS EXPECTED TO DEVELOP JUST SOUTH OF THE AREA THROUGH
THIS EVENING. THE CHANCE FOR SHOWERS AND EVEN A THUNDERSTORM WILL
INCREASE THIS AFTERNOON...AND WILL BECOME LIKELY TONIGHT. WARMER AIR
WILL MOVE IN ACROSS THE AREA THEN DURING THE DAY ON SATURDAY...AND
WILL REMAIN THROUGH THE DAY ON SUNDAY. A STRONG COLD FRONT WILL MOVE
THROUGH THE AREA LATE SUNDAY NIGHT AND DURING THE DAY ON MONDAY.
THIS WILL BRING SHOWERS AND A CHANCE OF STORMS WITH IT. MUCH COLDER
AIR WILL MOVE IN FOR THE FIRST HALF OF NEXT WEEK.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 322 AM EST FRI NOV 9 2012
MAIN FOCUS OF THE SHORT TERM CONTINUES TO BE DETERMINING PCPN TRENDS
THROUGH THE UPCOMING WEEKEND. NO REAL CHANGES WERE MADE AS THE
FORECAST IS ON TRACK.
LOW CLOUDS HAVE BEEN TRYING TO MOVE OUT OF THE AREA THIS MORNING. AS
THEY TRY TO MOVE OUT...THEY HAVE BEEN BACKBUILDING AS A RESULT OF
THE STRONG WARM AND MOIST ADVECTION IN PROGRESS FROM THE SE TEXAS
COAST INTO THE GREAT LAKES REGION. THEY ARE MAINLY IMPACTING AREAS
ALONG AND NORTH OF I-96. WE COULD SEE THESE CLOUDS MOVE OUT BRIEFLY
TODAY. HOWEVER THE OVERALL TREND WILL BE TO SEE MORE MID AND HIGH
LEVEL CLOUD COVER ADVECT IN TODAY.
WE WILL SEE THE NRN PERIPHERY OF THE DEVELOPING LLJ AXIS APPROACH
THE SRN PORTION OF THE AREA LATE THIS AFTERNOON. ALL THE MODELS ARE
GENERALLY SHOWING THAT WE SHOULD SEE SOME DEVELOPMENT OF PCPN LATE
TODAY DOWN SOUTH. THE LACK OF LOW LEVEL MOISTURE WILL LIMIT THE
AMOUNT OF PCPN INITIALLY. THE THREAT FOR PCPN WILL INCREASE THIS
EVENING AS WE SEE THE DEEPER MOISTURE FINALLY IN PLACE...AND THE LOW
LEVEL JET IS AS CLOSE AS IT GETS TO THE AREA. THE THREAT WILL
GRADUALLY SHIFT NORTH THROUGH SAT AFTERNOON AS THE WARM FRONT LIFTS
NORTH.
THE THREAT OF THUNDER REMAINS AS THE MODELS ARE ALL INDICATING
ELEVATED LI/S DROPPING BELOW ZERO C. THERE IS NOT A LOT OF
INSTABILITY...BUT ENOUGH TO CONTINUE TO JUSTIFY THE MENTION OF
THUNDER IN THE FCST.
WE SHOULD SEE LITTLE TO NO PCPN IN THE PERIOD FROM LATE SAT
AFTERNOON UNTIL LATE SUN AFTERNOON. THE WARM FRONT WILL BE WELL
NORTH OF THE AREA BY SAT EVENING...AND THE UPPER RIDGE AXIS IS
ACTUALLY ALMOST OVERHEAD. WE CAN NOT RULE OUT A RANDOM SHOWER OR
STORM DURING THIS PERIOD AS WE COULD SEE EMBEDDED SHORT WAVES IN THE
FLOW POTENTIALLY KICK SOMETHING OFF. WE WILL BE IN THE WARM
SECTOR...AND SHOULD SEE TEMPS JUMP INTO THE 60S DURING THE DAY ON
SAT AND SUN.
WE WILL SEE THE CHC OF RAIN INCREASE LATE SUN AFTERNOON TO THE WEST.
THIS OCCURS AS WE SEE THE COLD FRONT AND THE LONG WAVE TROUGH MAKE A
RUN FOR THE CWFA. IT IS LOOKING LIKE THE MAJORITY OF THE RAIN WILL
HOLD OFF UNTIL SUN NIGHT WHEN THE FRONT AND UPPER WAVE WILL BE MUCH
CLOSER. INSTABILITY IS LACKING...SO ANY KIND OF SEVERE THREAT IS
QUITE LIMITED.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 322 AM EST FRI NOV 9 2012
NO SIGNIFICANT CHANGES TO THE FORECAST. CONSISTENT MODEL AGREEMENT
ON TIMING THE COLD FROPA THROUGH FOR LATE SUNDAY NIGHT INTO MONDAY
AND THIS IS WHEN THE HIGHEST POPS WILL BE. SHARP COLD FRONT COULD
SEE BAND OF HEAVIER RAIN AHEAD OF IT WITH SOME LINGERING SNOW
SHOWERS ON THE BACK SIDE.
KEPT THUNDER ON SUNDAY NIGHT CONFINED TO THE SOUTHWEST FORECAST AREA
TO MESH WITH SURROUNDING OFFICES. INSTABILITY IS LIMITED BUT A
RUMBLE OF THUNDER CANNOT BE RULED OUT. LIKELY POPS SUNDAY NIGHT FOR
ALL BUT THE SE FORECAST AREA AND LIKELY POPS ALL ZONES ON MONDAY.
CHANGEOVER TO SNOW EXPECTED MONDAY NIGHT AS SHARP THERMAL TROUGH
MOVES IN WITH 850MB TEMPS FALLING BELOW MINUS 10C BY TUESDAY. THIS
WILL AID LAKE EFFECT AND LINGERING SNOW SHOWERS SHOULD WIND DOWN
TUESDAY AND END TUESDAY NIGHT AS SFC HIGH BUILDS IN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1148 PM EST THU NOV 8 2012
THE LOW CLOUDS ARE STARTING TO CLEAR NEAR AND SOUTH OF INTERSTATE
94 BUT NEAR INTERSTATE 96... THE CLOUDS SEEM TO WANT TO REDEVELOP
OFF SHORE OF MKG AND MOVE INLAND. LOOKING AT THE RAP AND NAM12
FROM 00Z IT WOULD SEEM THE LOW CLOUDS WILL HAVE A HARD TIME REALLY
CLEARING NEAR AND NORTH OF INTERSTATE 96 BEFORE 09Z SO I HELP THE
CLOUDS IN THERE TILL THEN. I EXPECT MVFR VSBY FOR MOST OF THE
INLAND TAF SITES.
THE DEVELOPING WARM FRONT SHOULD RESULT IN SHOWERS DEVELOPING
FRIDAY NIGHT SO I PUT THEM IN THE TAF AFTER 00Z.
&&
.MARINE...
ISSUED AT 322 AM EST FRI NOV 9 2012
THE MAIN PERIOD OF CONCERN FOR MARINE INTERESTS WILL BE FROM
SATURDAY THROUGH MONDAY AS WINDS INCREASE IN ASSOCIATION WITH A
STRONG STORM SYSTEM THAT WILL EVENTUALLY MOVE THROUGH THE AREA.
SMALL CRAFT ADVISORIES LOOK LIKE A SURE THING. THERE IS SOME
POTENTIAL FOR GALES WITH STRONG WINDS ONLY 1-2K FEET UP. THE STRONG
CORE OF WINDS SHOULD REMAIN ELEVATED DUE TO THE STRONG WARM AIR
MOVING IN OVER THE RELATIVELY COOLER WATERS.
&&
.HYDROLOGY...
ISSUED AT 322 AM EST FRI NOV 9 2012
WE CONTINUE TO EXPECT THAT WE WILL NOT HAVE ANY HYDROLOGY ISSUES
THROUGH MID WEEK NEXT WEEK. RIVER LEVELS REMAIN AROUND AVERAGE...AND
WE DO NOT SEE A GOOD POTENTIAL FOR HEAVY RAINS. THIS INCLUDES THE
TWO PERIODS OF RAIN EXPECTED THROUGH MONDAY MORNING.
THE TREND HAS BEEN FOR A LITTLE LESS RAINFALL EXPECTED WITH THE
DEVELOPMENT OF THE WARM FRONT LATER TODAY AND THROUGH SATURDAY
AFTERNOON. MOST LOCATIONS SHOULD GENERALLY SEE LESS THAN A QUARTER
OF AN INCH.
THE OTHER PERIOD OF RAINFALL WILL COME ALONG THE STRONG COLD FRONT
SUNDAY NIGHT AND MONDAY. WE CONTINUE TO EXPECT RAINFALL AMOUNTS WILL
BE BETWEEN A QUARTER AND THREE QUARTERS OF AN INCH OF RAINFALL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...OSTUNO
AVIATION...WDM
HYDROLOGY...NJJ
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1148 PM EST THU NOV 8 2012
.SYNOPSIS...
ISSUED AT 345 PM EST THU NOV 8 2012
A WARM FRONT WILL LIFT NORTH INTO SOUTHERN LOWER MICHIGAN BRINGING
MILDER TEMPERATURES FOR THE COMING WEEKEND. THE FRONT WILL ALSO
CREATE A THREAT OF SHOWERS AND THUNDERSTORMS FRIDAY NIGHT INTO
SATURDAY.
THE WARM FRONT WILL LIFT NORTH OF THE REGION SATURDAY NIGHT AND
TEMPORARILY END THE CHANCE OF RAIN... BUT A COLD FRONT APPROACHING
FROM THE WEST WILL BRING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS
SUNDAY NIGHT INTO EARLY MONDAY. COLD AIR WILL RETURN AGAIN BEHIND
THAT COLD FRONT FOR NEXT WEEK AND SOME SNOW FLAKES MAY BE SEEN AS
WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 345 PM EST THU NOV 8 2012
A STUBBORN AREA OF STRATUS HAS BEEN IMPACTING THE GRR CWFA TODAY...
AND THE QUESTION NOW BECOMES WHAT HAPPENS WITH THESE CLOUDS TONIGHT.
THE CLOUDS SEEM TO BE FAIRLY CLOSELY LINKED WITH THE 925 AND 850 MB
THERMAL TROUGH... WHICH IS PROGGED TO MOVE EAST AFTER 06Z AS THE
WARM AIR PUSHES IN FROM THE SOUTHWEST. USING THE LOW LEVEL THERMAL
TROUGH AS A PROXY FOR THE CLOUD BEHAVIOR... WILL HAVE MOSTLY CLOUDY
THIS EVENING THEN GO WITH SKIES BECOMING PARTLY CLOUDY AFTER
MIDNIGHT.
BELIEVE FRIDAY MORNING WILL START OUT WITH ABUNDANT SUNSHINE... BUT
INCREASING CLOUDS ARE LIKELY IN THE AFTERNOON AS THE WARM FRONT
MOVES IN. ALSO ADDED A SLIGHT CHANCE OF LIGHT RAIN SHOWERS LATE IN
THE DAY DUE TO LOWERING CPD/S AND INCREASING MOISTURE/THETA-E
CONVERGENCE NORTH OF THE SHARPENING WARM FRONT.
LOOKS LIKE A PRETTY GOOD CHANCE OF SHOWERS AND TSTMS ON FRIDAY NIGHT
INTO SATURDAY WITH 30+ KT SWLY LOW LEVEL JET AIMED INTO SRN MICHIGAN
ALONG THE WEST-EAST ORIENTED WARM FRONT AND PWAT VALUES EXCEEDING
ONE INCH. PROGGED 850 TO 500 MB THETA LAPSE RATES OF ZERO TO -3
INDICATE A DECENT POTENTIAL FOR ELEVATED CONVECTION/TSTMS.
COVERAGE/FREQUENCY OF CONVECTION WILL PROBABLY DECREASE HEADING INTO
LATE SATURDAY AND SATURDAY NIGHT AS THE WARM FRONT LIFTS NORTH.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 345 PM EST THU NOV 8 2012
UNSEASONABLY WARM CONDITIONS ARE ANTICIPATED SUNDAY IN STRONG
SOUTHERLY FLOW WAA IN ADVANCE OF THE APPROACHING COLD FRONT. MAX
TEMPS WILL REACH WELL INTO THE 60S. A SHOWER OR TWO IS POSSIBLE
DURING THE DAY BUT THE VAST MAJORITY OF THE DAY SHOULD BE DRY UNTIL
THE COLD FRONT BRINGS RAIN AND A SLIGHT CHANCE OF THUNDERSTORMS LATE
SUNDAY NIGHT.
POST FRONTAL RAIN WILL LINGER MONDAY FOLLOWED BY MIXED RAIN AND SNOW
SHOWERS LATE MONDAY/MONDAY NIGHT AS H8 TEMPS FALL TO -8 TO -10 C BY
12Z TUE ALONG WITH EXTENSIVE LINGERING LOW TO MID LEVEL MOISTURE. A
FEW LIGHT SNOW SHOWERS/FLURRIES MAY LINGER INTO TUESDAY MORNING
BEFORE SFC RIDGING/ANTICYCLONIC FLOW BRINGS DRY BUT COOL WEATHER
LATE TUESDAY THROUGH WEDNESDAY.
FAIR WX WILL CONTINUE INTO LATE WEEK WITH THE RIDGE STILL IN CONTROL
ALONG WITH A GRADUAL MODERATING TREND OF TEMPS LATE NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1148 PM EST THU NOV 8 2012
THE LOW CLOUDS ARE STARTING TO CLEAR NEAR AND SOUTH OF INTERSTATE
94 BUT NEAR INTERSTATE 96... THE CLOUDS SEEM TO WANT TO REDEVELOP
OFF SHORE OF MKG AND MOVE INLAND. LOOKING AT THE RAP AND NAM12
FROM 00Z IT WOULD SEEM THE LOW CLOUDS WILL HAVE A HARD TIME REALLY
CLEARING NEAR AND NORTH OF INTERSTATE 96 BEFORE 09Z SO I HELP THE
CLOUDS IN THERE TILL THEN. I EXPECT MVFR VSBY FOR MOST OF THE
INLAND TAF SITES.
THE DEVELOPING WARM FRONT SHOULD RESULT IN SHOWERS DEVELOPING
FRIDAY NIGHT SO I PUT THEM IN THE TAF AFTER 00Z.
&&
.MARINE...
ISSUED AT 345 PM EST THU NOV 8 2012
WHILE THE SOUTHERLY FLOW WILL BE INCREASING TONIGHT... IT APPEARS
THAT CONDITIONS WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. THE
BEST CHANCE OF SEEING ADVISORY CRITERIA WINDS AND WAVES WILL BE LATE
SATURDAY INTO SATURDAY NIGHT WHEN THE SFC WARM FRONT LIFTS OFF TO
THE NORTH.
&&
.HYDROLOGY...
ISSUED AT 345 PM EST THU NOV 8 2012
EXPECTED QPF WITH THE WARM FRONT FRIDAY NIGHT AND SATURDAY IS 0.10
TO 0.25 AND LOCALLY HIGHER AMOUNTS TO 0.50. EXPECTED QPF AMOUNTS
WITH THE COLD FRONT SUNDAY NIGHT INTO EARLY MONDAY SHOULD BE 0.25 TO
0.75 WITH UP TO AN INCH POSSIBLE. NO HYDRO ISSUES ARE FORESEEN WITH
THESE QPF AMOUNTS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...LAURENS
AVIATION...WDM
HYDROLOGY...MEADE
MARINE...MEADE
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1158 PM CST THU NOV 8 2012
.DISCUSSION.../ISSUED AT 900 PM CST/
COLD FRONT MOVING SOUTHEAST THROUGH NORTHWEST IOWA WITH STRATUS
SPREADING SOUTH ACROSS CWA. CURRENTLY STRATUS IS NEAR I90 AND WEST
OF BUFFALO RIDGE IN SOUTHWEST MINNESOTA. STRATUS MAY HAVE A HARD
TIME GETTING EAST OF BUFFALO RIDGE TONIGHT WITH THE LOW LEVEL
NORTHEAST FLOW KEEPING THE CLOUDS TO THE WEST. WILL TREND MOST OF
NIGHT CLOUDS SAGGING SOUTH WEST OF BUFFALO RIDGE...BUT OVER
TIME...STRATUS SHOULD MOVE IN. CLOUDS SHOULD HELP TO HOLD UP
TEMPERATURES TONIGHT...AND DID BUMP UP A FEW DEGREES ACROSS THE
NORTH.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
IFR CEILINGS WILL BE IN PLACE OVER MOST OF THE AREA THROUGH MID
MORNING. PARTS OF NORTHWEST IOWA COULD AVOID THIS STRATUS...BUT FOG
COULD FILL IN LATE TONIGHT IN AREAS NEAR THE EDGE OF STRATUS. MUCH
OF THIS STRATUS WILL BREAK UP A BIT FROM THE EAST AS DRIER AIR
PUSHES IN. CEILINGS WILL LIKELY LIMB BACK INTO THE MVFR CATEGORY BY
LATE FRIDAY MORNING AND POSSIBLY INTO LOW END VFR. AREAS EAST OF
INTERSTATE 29 COULD SEE SCATTERED CLOUD COVER FOR A TIME TODAY. /08
&&
.PREVIOUS DISCUSSION.../ISSUED AT 356 PM CST/
FRONTAL BOUNDARY WILL CONTINUE TO WORK ITS WAY SOUTHEAST ACROSS THE
CWA THIS AFTERNOON AND EVENING. MAIN FORECAST ISSUE TONIGHT INTO
TOMORROW WILL BE CLOUD COVER AND TEMPERATURES. STRATUS DECK
ASSOCIATED WITH THE LOW LEVEL COLD AIR ADVECTION PUSH IS CURRENTLY
MOVING SOUTH INTO NORTHERN SOUTH DAKOTA. MODELS HANDLE THIS FEATURE
DIFFERENTLY. LOOKS LIKE THE NAM IS DECOUPLING THE BOUNDARY LAYER TOO
MUCH TONIGHT...WHICH ACTS TO KEEP THE STRATUS AT BAY. FEEL LIKE
SOMETHING CLOSER TO THE RAP SOLUTION IS MOST LIKELY...WHERE THE COLD
AIR ADVECTION KEEPS THE BOUNDARY LAYER MIXED ENOUGH TO KEEP THE
STRATUS LOCKED IN AND SPREADING SOUTH. COULD EVEN SEE SOME SPOTTY
DRIZZLE IN THE EASTERLY UPSLOPE LOCATIONS OF SOUTHWEST MINNESOTA.
THUS WILL LEAN TOWARDS THIS SOLUTION WITH CLOUDS INCREASING FROM
NORTH TO SOUTH TONIGHT. LOWS MAINLY IN THE 30S...WITH THE CLOUDS AND
BREEZE PREVENTING TEMPS FROM FALLING TOO FAR.
ON FRIDAY...LOW STRATUS WILL BEGIN TO ERODE FROM SOUTH TO NORTH.
HOWEVER AT THE SAME TIME...SOUTHEASTERLY WINDS WILL ADVECT IN
ADDITIONAL MOISTURE AROUND 850 MB...ALLOWING ANOTHER STRATUS DECK TO
QUICKLY FORM. THUS THINK MUCH OF THE AREA STAYS CLOUDY THROUGH THE
DAY...WITH SOUTHERN AREAS HAVING THE BEST CHANCE OF SEEING A BIT OF
MORNING SUN. MOISTURE WILL CONTINUE TO DEEPEN THROUGH THE DAY...WITH
PORTIONS OF SOUTHWEST MINNESOTA AND NORTHWEST IOWA POSSIBLY SEEING
SOME DRIZZLE BY MID AFTERNOON AS WE SEE WEAK LIFT IN THE NEARLY
SATURATED 0-1 KM LAYER. FORECAST CONFIDENCE IS OVERALL PRETTY LOW ON
FRIDAY. THE NAM IS A LOT SLOWER THAN THE GFS WITH STRATUS
FORMATION...WITH THE GFS THE FASTEST. THE FORECAST FOLLOWS CLOSEST
TO THE GFS SOLUTION...WHICH APPEARS TO BE HANDLING THINGS BEST AT
THE CURRENT TIME. THUS WITH THE CLOUDS AROUND...LOWERED HIGHS A FEW
DEGREES FOR TOMORROW...GENERALLY MID TO UPPER 40S NORTH TO MID 50S
SOUTHEAST. IF A SOLUTION CLOSER TO THE NAM PANS OUT RESULTING IN A
LONGER PERIOD OF SUN...HIGHS WILL BE A GOOD 5 DEGREES WARMER...AND
IF THE CLOUDS STAY LOCKED IN EVEN MORE THAN EXPECTED...HIGHS WOULD
BE A FEW DEGREES COOLER THAN CURRENT FORECAST. /CHENARD
COMPLICATED FORECAST ANTICIPATED FOR THE WEEKEND WITH THE WELL
ADVERTISED SURFACE LOW AND BROAD SURFACE TROUGH TRACKING THROUGH THE
AREA. FOR FRIDAY NIGHT...LOW STRATUS WILL REMAIN A CONCERN WITH ALL
MODELS KEEPING A LOW CLOUD DECK IN PLACE OVERNIGHT. THE GFS AND
ECMWF CONTINUE TO INDICATE A DEEPER MOIST LAYER THAN THE NAM...WHICH
POINTS TO A GREATER POTENTIAL FOR LIGHT FOG/MIST INSTEAD. HAVE
OPTED TO FOLLOW THE GFS/ECMWF AND THE POTENTIAL FOR SOME DRIZZLE OR
VERY LIGHT RAIN POSSIBLE IN OUR NORTHEAST CORNER OVERNIGHT. LOWER
VISIBILITIES OR MIST WOULD BE REASONABLE IN THIS AREA AS WELL...BUT
DO NOT THINK THE FOG WILL BE DENSE ENOUGH TO MENTION IN THE GRIDS.
TEMPERATURES WILL BE QUITE MILD OVERNIGHT IN THE 40S.
SATURDAY HAS THE POTENTIAL FOR BEING A VERY MILD DAY...PARTICULARLY
ACROSS OUR EASTERN HALF. THE SURFACE LOW GRADUALLY LIFTS NORTH
NORTHEAST THROUGH THE CENTER OF THE CWA INTO SOUTHWEST MINNESOTA.
IT DOES LOOK LIKE THE STRATUS WILL BEGIN TO BREAK EARLY IN THE DAY
ACROSS OUR EAST AS THE WARM FRONT LIFTS NORTH AND SOUTHERLY FLOW
TAKES OVER. COULD SEE SOME WEAK MID LEVEL INSTABILITY IN THIS WARM
SECTOR IN THE AFTERNOON AND EVENING ACROSS NORTHWEST IOWA WHICH
WOULD BRING AN ISOLATED THREAT FOR SOME THUNDERSTORMS IN ADDITION TO
THE RAIN SHOWERS WHICH SHOULD BEGIN WORKING INTO THE AREA. THE COLD
FRONT FINALLY KICKS THROUGH OUR EASTERN HALF BY LATE SATURDAY
EVENING...WITH THE STRATIFORM PRECIPITATION SPREADING THROUGH THE
REMAINDER OF THE FORECAST AREA BEHIND IT. MUCH COLDER AIR WILL
QUICKLY ARRIVE OVERNIGHT...TRANSITIONING THE RAIN TO A MIX AND THEN
ENTIRELY SNOW BY DAYBREAK.
FOR EARLY SUNDAY...THE LINGERING MID LEVEL EXITS TO OUR EAST WITH
COOLER AND DRIER AIR WORKING INTO THE REGION. THE NAM IS THE FASTEST
IN EXITING THE WAVE WITH THE BULK OF THE EVENT OVER LATE SUNDAY
NIGHT...WHILE THE GFS AND ECMWF SUGGEST A LINGERING BAND OF LIGHT
SNOW OVER THE FORECAST AREA INTO MID DAY. THE BULK OF THE SNOW WILL
BE OVER AT THIS POINT...BUT HAVE HELD ONTO A CHANCE FOR THE MORNING.
THE HIGHEST SNOWFALL AMOUNTS ARE EXPECTED WEST OF THE JAMES RIVER
WHERE 2 TO 3 INCHES ARE EXPECTED...WHILE NORTHWEST IOWA CAN EXPECT A
HALF INCH OR LESS. VERY BRISK NORTHWEST WINDS WILL COMBINE WITH
HIGHS ONLY TOPPING OUT IN THE MID 20S TO MID 30S.
IN THE EXTENDED...QUIETER WEATHER IS ON TAP EARLY NEXT WEEK INTO MID
WEEK AS THE PATTERN TRANSITIONS INTO A MORE ZONAL FLOW. HIGHS ON
MONDAY WILL REMAIN COLD IN THE UPPER 20S TO LOWER 30S...THEN
GRADUALLY MODERATE INTO THE 40S BY MID WEEK. DID DROP LOWS A FEW
DEGREES BELOW THE ALLBLEND ON SUNDAY NIGHT...BUT SOME LINGERING
WINDS WOULD LIKELY PREVENT TEMPERATURES FROM REALLY DROPPING OFF.
LOWS WILL BE IN THE TEENS SUNDAY NIGHT AND MONDAY NIGHT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1015 PM PST Thu Nov 8 2012
.SYNOPSIS...
The weather pattern in the Pacific Northwest will become more
active tonight when the first of a number of winter weather systems
impacts the region and exits early Saturday Morning. The remainder
of the weekend may remain precipitation free until yet another low
pressure system passage brings snow and rain to the region Monday
and Tuesday.
&&
.DISCUSSION...
Update: We`ve been tracking low pressure and the band of precipitation
wrapping around it. Across much of northeast third of Washington
and the Idaho Panhandle, from the higher Palouse through much of
the Spokane area and northern Mountains eastward, temperatures
have been cold enough to support snow or at least a rain/snow mix.
On the West Plains, near our office, we picked up around 0.7
inches of snow on our snowboard since about 4 pm this afternoon.
The center of the developing low is best analyzed around 700mb and,
using IR satellite and RUC guidance, it has been tracking north-
northeast toward the Spokane/Whitman county border. A deformation
axis/700mb theta-e axis wrapped has been lifting in with it and at
of about 03Z (7PM) it wrapped from the central Panhandle, north
and west to near the eastern I-90 corridor. Lift from the
deepening low and parent upper trough, along with the deformation
axis has been helping to focus moisture and the resultant
precipitation. At the same time, more widely scattered showers are
found on its backside around the Basin. A bit of a dry slot is
coming up from the south, drying out part of the lower Palouse.
The short-range models continue to track to low and the
accompanying deformation axis (which will continue to provide a
focus for precipitation) northward. Guidance suggests the primary
core of the precipitation starting to shift north of the I-90
corridor going through the overnight into Friday morning. This
trend seems valid. Through Friday the deformation axis weakens
near the foothills of the Selkirks/Long Lake area and gradually
starts to track east-southeast by late Friday.
Given this depicted trend and recalling previous events, oftentimes
the deformation axis/boundary stalls and provides more focused
band of precipitation within the broader precipitation shield north
of I-90, from the base of the Selkirk into areas near and north of
Coeur d`Alene. Given this thinking and the fact thus far models
seem to have underdone the precipitation amounts I went ahead and
raised QPF and accompanying snow amounts slightly. This does not
change the overall highlights in effect, but some areas could see
localized amounts near or over 6 inches. This is primarily focused
across areas along and north of a line from Wellpinit to Colbert
to Hayden and the Rathdrum Prairie. /J. Cote`
&&
.AVIATION...
06Z TAFS: Low pressure will continue to deepen over eastern WA
tonight before slowly weakening Friday and edging east.
Moisture and cold air wrapped in it will continue to provide
areas of snow, occasionally mixed with rain near the southern
TAF sites. IFR cigs and vis will be most persistent around KGEG to
KCOE (and areas north), while VFR/MVFR conditions will be more
prevalent elsewhere. The precipitation is expected dissipate
around the TAF sites through the late morning to afternoon Friday,
with cigs and vis improving toward MVFR and eventually toward VFR
by late day; however watch for lowering cigs again late Friday
night (into Saturday morning). /J. Cote`
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 28 33 19 31 19 33 / 100 80 20 0 0 10
Coeur d`Alene 29 33 16 30 17 34 / 100 90 30 10 0 10
Pullman 29 33 20 31 18 34 / 80 80 30 10 10 0
Lewiston 33 38 24 35 22 38 / 70 60 20 10 0 0
Colville 28 37 20 35 20 36 / 100 80 10 0 0 10
Sandpoint 26 31 14 29 16 34 / 100 90 20 0 0 10
Kellogg 28 30 17 26 17 30 / 100 100 60 10 0 0
Moses Lake 29 41 22 38 21 38 / 20 20 10 0 0 0
Wenatchee 32 40 24 38 23 38 / 20 20 10 10 0 0
Omak 30 39 22 37 20 38 / 20 30 10 0 0 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 4 PM PST Friday for Central
Panhandle Mountains-Coeur d`Alene Area-Idaho Palouse-
Northern Panhandle.
Winter Weather Advisory until 4 PM PST Friday for Lewis and
Southern Nez Perce Counties.
WA...Winter Weather Advisory until 4 PM PST Friday for Northeast
Mountains-Okanogan Highlands-Spokane Area-Washington
Palouse.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
520 AM CST FRI NOV 9 2012
.AVIATION...12Z KGRI TAF. ANOTHER HOUR OR TWO OF VFR CONDITIONS
REMAIN POSSIBLE...BUT PREVAILING IFR CONDITIONS ARE FORECAST 13Z-
17Z...WITH TEMPORARY LIFR CONDITIONS ALSO FORECAST. VFR CONDITIONS
ARE THEN EXPECTED 17Z ONWARD. SATELLITE IMAGERY INDICATES A
STRATUS DECK APPROACHING KGRI FROM THE NORTH AND GIVEN THE CURRENT
MOTION OF THIS DECK...CEILINGS BELOW 1000FT AGL SHOULD BE REALIZED
BY 13Z. GUIDANCE SUGGESTS THIS STRATUS SHOULD SLOW AND ACTUALLY
BEGIN RETROGRADING TO THE NORTH A LITTLE LATER THIS MORNING...WITH
VFR CONDITIONS RESTORED BY 17Z. THE SURFACE WIND WILL REMAIN
GENERALLY LIGHT AND VARIABLE DURING THE TAF PERIOD. THIS LIGHT
WIND...WORKING IN CONCERT WITH DECREASING LOW LEVEL DEWPOINT
DEPRESSIONS...MAY ALSO PROMOTE A PERIOD OF RESTRICTED VISIBILITIES
IN BR...13Z-17Z.
&&
.PREV DISCUSSION... /ISSUED 445 AM CST FRI NOV 9 2012/
SHORT TERM...THROUGH 12Z MONDAY. OVERNIGHT UPPER AIR ANALYSIS
INDICATES LONG WAVE TROUGHING OVER THE WESTERN AND EASTERN
CONUS...AND A RIDGE PREVAILING OVER THE CENTRAL CONUS. A CLOSED
MID LEVEL LOW IS ALSO NOTED OVER THE NORTHWESTERN CONUS...WITH
ANOTHER CLOSED MID LEVEL CIRCULATION OVER THE NORTHEASTERN CONUS.
MID AND UPPER LEVEL JET ENERGY EXTENDS FROM CALIFORNIA...NORTHEAST
INTO THE NORTHERN PLAINS AND SOUTH CENTRAL CANADA...AND THEN
SOUTHEAST ACROSS THE OHIO VALLEY AND ON INTO THE SOUTHEASTERN
CONUS. TROPOSPHERIC FLOW IS NOT OVERLY STRONG NEAR OUR AREA AS A
RESULT...MAXING OUT AT AROUND 50KTS AT VARIOUS POINTS BETWEEN
500MB AND 200MB PER 00Z SOUNDING DATA FROM KLBF. WATER VAPOR
IMAGERY CLEARLY SHOWS THE CLOSED MID LEVEL LOWS OVER THE
NORTHWESTERN AND NORTHEASTERN CONUS. INCREASING VALUES OF MID
LEVEL MOISTURE ARE ALSO NOTED ON WATER VAPOR IMAGERY ADVECTING
NORTHEAST ALONG THE FRONT OF THE LONG WAVE TROUGH...INTO THE ROCKY
MOUNTAIN RANGE AND PLAINS. SOME OF THIS MID LEVEL MOISTURE IS
PROMOTING INCREASING MID TO HIGH LEVEL CLOUD COVER OVER PORTIONS
OF THE CENTRAL PLAINS. AT THE SURFACE A STATIONARY BOUNDARY IS
NOTED EXTENDING FROM WESTERN IOWA...SOUTHWEST INTO NORTHEASTERN
KANSAS AND ON INTO SOUTHEASTERN COLORADO. THE LOW LEVEL WIND FIELD
ACROSS OUR AREA REMAINS FROM THE NORTH AS A RESULT...BUT IS FAIRLY
LIGHT AT AROUND 5KTS. IN ADDITION TO THE AFOREMENTIONED MID TO
HIGH LEVEL CLOUDS BEGINNING TO WORK INTO THE REGION...SATELLITE
IMAGERY ALSO INDICATES A STRATUS DECK OVER MUCH OF THE NORTHERN
PLAINS...WITH THIS DECK MOVING SOUTH/SOUTHEAST AT AROUND 20KTS AND
ALREADY INFILTRATING PORTIONS OF CENTRAL NEBRASKA.
GUIDANCE FROM THE NAM...RAP...AND OPERATIONAL GFS ALL SUGGEST
ISENTROPIC UPGLIDE AND SATURATION...PRIMARILY ALONG THE 290-295K
SURFACES...WILL CONTINUE TO PROMOTE STRATUS OVER PORTIONS OF THE
REGION THROUGH MIDDAY. THERE IS SOME UNCERTAINTY AS TO HOW FAR
SOUTH THIS STRATUS DECK WILL MOVE ACROSS OUR CWA. THE OPERATIONAL
GFS REMAINS THE MOST AGGRESSIVE IN BRINGING THE DECK ACROSS OUR
ENTIRE CWA...WHILE THE NAM AND RAP BOTH SUGGEST THE NORTHERN HALF
OF OUR CWA WILL BE THE ONLY LOCATIONS TO OBSERVE THIS STRATUS.
SATELLITE IMAGERY INDICATES THE STRATUS DECK HAS SLOWED THROUGH
THE PAST 2-3 HOURS AND IT NOW SEEMS UNLIKELY THIS STRATUS WILL
MAKE IT TO OUR KANSAS COUNTIES BY 12Z...WHICH IS WHAT THE
OPERATIONAL GFS SUGGESTS. GIVEN THIS...OPTED TO PLAY CLOSER TO NAM
AND RAP GUIDANCE BY KEEPING THE FORECAST STRATUS PRIMARILY OVER
THE NORTHERN HALF OF THE CWA. GUIDANCE FROM THE NAM AND RAP ALSO
SUGGEST THE LOW LEVEL BAROCLINIC ZONE TO OUR SOUTH/SOUTHEAST WILL
LIFT NORTH AS A WARM FRONT TODAY...THUS CARRYING THE PRIMARY AXIS
OF ISENTROPIC UPGLIDE FARTHER NORTH WHICH SHOULD HELP CLEAR THE
STRATUS FROM MUCH OF OUR CWA BY MIDDAY. ALTHOUGH THE INCREASING
MID AND HIGH LEVEL CLOUDS MAY KEEP TEMPERATURES FROM MEETING THEIR
FULL DIURNAL POTENTIAL TODAY...THERE SHOULD BE ENOUGH DIABATIC
HEATING FOR 20-25 DEGREE TEMPERATURE RISES WHICH SHOULD PRESENT
AFTERNOON HIGHS GENERALLY IN THE 60S AND 70S...WITH THE ONLY
EXCEPTION BEING ACROSS OUR FAR NORTH WHERE THE STRATUS MAY KEEP
TEMPERATURES IN THE 50S.
THE BIG WEATHER STORY CONTINUES TO REVOLVE AROUND THE INCOMING
SYSTEM FOR THIS WEEKEND. GUIDANCE CONTINUES TO SUGGEST THE MID
LEVEL LOW...CURRENTLY OVER THE NORTHWESTERN CONUS...WILL OPEN UP
INTO A WAVE AND MOVE EAST INTO THE CENTRAL CONUS TONIGHT THROUGH
SUNDAY. AS THE MID LEVEL TROUGH APPROACHES FROM THE
WEST...RESULTANT SURFACE CYCLOGENESIS IS EXPECTED TO COMMENCE OVER
THE HIGH PLAINS OF NORTHEASTERN COLORADO OVERNIGHT TONIGHT. THIS
SURFACE LOW IS THEN EXPECTED TO QUICKLY EJECT NORTHEAST ACROSS THE
CENTRAL PLAINS AS THE MID LEVEL TROUGH AXIS APPROACHES OUR AREA
FROM THE WEST. AS THE SURFACE LOW MOVE NORTHEAST...AN ASSOCIATED
COLD FRONT IS EXPECTED TO SWEEP ACROSS OUR AREA SATURDAY AFTERNOON
INTO SATURDAY NIGHT.
QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST MID LEVEL THERMAL ADVECTION AHEAD OF THE MID LEVEL TROUGH
AXIS...WORKING IN CONCERT WITH LOW LEVEL CONVERGENCE ALONG THE LOW
LEVEL BAROCLINIC ZONE...WILL PROVIDE SUFFICIENT LIFT FOR
CONVECTIVE INITIATION NEAR THE BAROCLINIC ZONE SATURDAY AFTERNOON.
AT THIS TIME IT APPEARS THIS CONVECTION WILL INITIALIZE IN THE
VICINITY OF A LINE EXTENDING FROM FULLERTON...TO GRAND ISLAND...TO
PHILLIPSBURG. INCREASED VALUES OF LOW LEVEL MOISTURE AHEAD OF THE
LOW LEVEL BAROCLINIC ZONE...ALONG WITH INCREASING MID LEVEL LAPSE
RATES WITH THE APPROACH OF THE MID LEVEL TROUGH AXIS...SHOULD BE
SUFFICIENT ENOUGH TO PROVIDE 0-1MLCAPE VALUES ON THE ORDER OF
1000J/KG PER THE NAM AND OPERATIONAL GFS. IN ADDITION TO THE
POTENTIAL INSTABILITY...INCREASING MID AND UPPER LEVEL JET ENERGY
WILL ALSO LIKELY PROVIDE DEEP LAYER BULK SHEAR VALUES IN EXCESS
50KTS ACROSS MUCH OF THE REGION. ALSO...FORECAST PROXIMITY
SOUNDINGS FROM ACROSS THE CWA...PER THE NAM...SUGGEST A VEERING
LOW LEVEL WIND PROFILE FOR LOCATIONS STILL AHEAD OF THE LOW LEVEL
BAROCLINIC ZONE...WITH THE NAM ALSO SUGGESTING 0-1KM SRH WILL
APPROACH 300M^2/S^2 ACROSS EAST/SOUTHEASTERN PORTIONS OF OUR CWA.
NOW...INCREASING MID AND HIGH LEVEL CLOUDS WILL LIKELY KEEP
DIABATIC HEATING DOWN A TOUCH THROUGH MUCH OF THE DAY WHICH WILL
HELP SUSTAIN SOMETHING OF A CAPPING INVERSION...WHICH MEANS
INITIAL CONVECTIVE DEVELOPMENT COULD BE IN THE FORM OF A FEW
DISCRETE CELLS IN THE VICINITY OF THE LOW LEVEL BAROCLINIC ZONE.
GIVEN THE VERY STRONG DEEP LAYER BULK SHEAR...SUPER CELL
DEVELOPMENT WILL BE MORE THAN POSSIBLE AND GIVEN THIS...WILL
CONTINUE OUTLOOKING LARGE HAIL IN THE HWO. ADDITIONAL CONVECTIVE
DEVELOPMENT ALONG THE BAROCLINIC ZONE COULD THEN POTENTIALLY
EVOLVE INTO A QLCS WITH STRONG OUTFLOW WINDS AT THE SURFACE
REMAINING VERY POSSIBLE. WILL CONTINUE TO CARRY SEVERE
THUNDERSTORM WIND WORDING IN HWO AS WELL. FINALLY...GIVEN THE LOW
LEVEL SHEAR AS INDICATED BY THE NAM...WILL ALSO GO AHEAD AND
MENTION ISOLATED TORNADIC DEVELOPMENT IN ASSOCIATION WITH THE
INITIAL CONVECTION DURING THE LATE AFTERNOON HOURS.
STRONG WINDS WILL NOT ONLY BE A THREAT WITH AFTERNOON AND EVENING
THUNDERSTORM ACTIVITY ON SATURDAY...BUT STRONG SYNOPTIC WINDS WILL
ALSO BE OBSERVED ACROSS MUCH OF THE CWA SATURDAY. AS SURFACE
CYCLOGENESIS CONTINUES ACROSS THE HIGH PLAINS SATURDAY...THE LOW
LEVEL PRESSURE GRADIENT IS EXPECTED TO INTENSIFY GREATLY HEADING
INTO SATURDAY AFTERNOON...ESPECIALLY ACROSS THE SOUTHEASTERN ONE-
HALF OF THE CWA. IN ADDITION...FORECAST PROXIMITY SOUNDINGS FROM
ACROSS OUR CWA PER THE NAM AND OPERATIONAL GFS SUGGEST BOUNDARY
LAYER MIXING TO BETWEEN 850MB AND 800MB WILL BE REALIZED...WHICH
IS WHERE ~50KT WINDS WILL BE WAITING FOR TRANSPORT TO THE SURFACE.
INTERESTING TO NOTE THAT BOTH MET AND MAV GUIDANCE SUGGEST
PORTIONS OF OUR CWA WILL HIT WIND ADVISORY CRITERIA AT SOME POINT
DURING THE DAY SATURDAY...WITH MAV GUIDANCE SUGGESTING OUR
SOUTHWEST WILL HIT BETWEEN 18Z AND 21Z...AND THE NAM SUGGESTING
OUR SOUTHEAST WILL HIT CLOSER TO 00Z. RATHER THAN BLANKET A
MAJORITY OF OUR CWA WITH WIND ADVISORY WINDS...OPTED TO KEEP WINDS
JUST UNDER WIND ADVISORY ACROSS THE SOUTHEASTERN HALF OF THE CWA
WITH THE HOPES THAT WE WILL BE ABLE TO FINE-TUNE THE WIND FORECAST
AND INCREASE WINDS SOMEWHAT...INTO WIND ADVISORY CRITERIA...FOR
PORTIONS OF THE CWA ONCE THAT FORECAST BECOMES MORE CLEAR. WILL GO
AHEAD AND CONTINUE TO CARRY STRONG SYNOPTIC WIND WORDING IN THE
HWO FOR SATURDAY AFTERNOON. STRONG SYNOPTIC WINDS WILL NOT ONLY BE
A THREAT SATURDAY AFTERNOON...BUT WILL ALSO BE POSSIBLE SATURDAY
NIGHT INTO EARLY SUNDAY MORNING AFTER THE LOW LEVEL BAROCLINIC
ZONE CLEAR THE AREA. INTENSE LOW LEVEL PRESSURE RISES POST-FROPA
WILL PROMOTE YET ANOTHER INCREASE IN THE LOW LEVEL PRESSURE
GRADIENT ACROSS THE CWA 00Z-12Z SUNDAY...WITH GUIDANCE SUGGESTING
~20KT SUSTAINED WINDS WILL BE REALIZED ACROSS MUCH OF THE AREA.
WILL GO AHEAD AND CONTINUE CARRYING STRONG SYNOPTIC WIND WORDING
IN THE HWO FOR SATURDAY NIGHT/SUNDAY MORNING AS A RESULT.
WITH THE INFILTRATION OF A MUCH COLDER LOW LEVEL
AIRMASS...FORECAST PROXIMITY SOUNDINGS FROM THE ACROSS THE CWA PER
THE NAM...OPERATIONAL GFS AND EC ALL SUGGEST THE LOWER TROPOSPHERE
WILL BECOME SUPPORTIVE FOR SNOW ACROSS MUCH OF THE CWA SATURDAY
NIGHT INTO SUNDAY MORNING. AT THIS TIME IT APPEARS ANY
PRECIPITATION BEHIND THE LOW LEVEL BAROCLINIC WILL REMAIN FAIRLY
LIGHT ACROSS OUR CWA...THUS ANY SNOWFALL ACCUMULATIONS ACROSS OUR
CWA SHOULD REMAIN UNDER AN INCH. LOCATIONS WEST OF HIGHWAY 281 AND
NORTH OF I-80...WHICH IS WHERE THE LOW LEVEL COLD AIR ADVECTION
WILL BE FIRST TO INFILTRATE...SEEM MOST LIKELY TO OBSERVE THE MOST
SNOWFALL ACCUMULATION. IT IS WORTH NOTING THAT A FEW FORECAST
PROXIMITY SOUNDINGS SUGGEST A BRIEF PERIOD OF SLEET NEAR THE TRI-
CITIES AREA AS THE TRANSITION FROM RAIN TO SNOW BEGINS...BUT GIVEN
THE UNCERTAINTY AND BREVITY OF ANY SUCH POTENTIAL ACTIVITY...OPTED
TO HOLD OFF FROM MENTIONING THIS IN THE FORECAST FOR THE TIME
BEING.
FINALLY...TEMPERATURES LOOK TO FALL OFF DRAMATICALLY POST-FROPA
HEADING INTO SATURDAY NIGHT...AND WITH CONTINUED LOW LEVEL COLD
AIR ADVECTION AND LINGERING CLOUD COVER DURING THE DAY
SUNDAY...ITS DOUBTFUL TEMPERATURES WILL GO MUCH OF ANYWHERE DURING
THE DAY SUNDAY. LOWS IN THE MID 20S TO MID 30S ARE CURRENTLY
FORECAST FOR SATURDAY NIGHT...WITH TEMPERATURES STRUGGLING THROUGH
THE 30S DURING THE DAY SUNDAY. THE PASSAGE OF THE SURFACE RIDGE
AND THE INTRODUCTION OF LOW LEVEL RETURN FLOW SHOULD THEN PRESENT
A WARMING TREND TO FINISH OUT THE SHORT TERM FORECAST PERIOD.
FIRE WEATHER...A LOW LEVEL BAROCLINIC ZONE IS EXPECTED TO CLEAR
WESTERN PORTIONS OF OUR CWA BY LATE MORNING OR MIDDAY SATURDAY.
ALTHOUGH LOW LEVEL COLD AIR ADVECTION WILL BEGIN PUSHING INTO THE
AREA SHORTLY AFTER FROPA...THERE WILL BE A BRIEF PERIOD IN WHICH
LOW LEVEL DRY AIR ADVECTION WILL OUTWEIGH THE COLD AIR
ADVECTION...THUS ALLOWING LOW LEVEL RELATIVE HUMIDITY TO PLUMMET
AS WE HEAD INTO THE AFTERNOON HOURS SATURDAY. AT THIS TIME IT
APPEARS LOCATIONS GENERALLY WEST OF HIGHWAY 281 AND SOUTH OF I-80
WILL OBSERVE THE LOWEST RELATIVE HUMIDITY VALUES...SOMEWHERE NEAR
25%. THESE LOW VALUES OF RELATIVE HUMIDITY...WORKING IN CONCERT
WITH A STRONG LOW LEVEL WIND FIELD...SUSTAINED WELL ABOVE 17KTS
AND GUSTS WELL ABOVE 22KTS...WILL PROVIDE AN ELEVATED FIRE WEATHER
DANGER SATURDAY AFTERNOON. AS A RESULT...WILL GO AHEAD AND PRESENT
ELEVATED FIRE WEATHER WORDING IN THE FWF AND HWO.
LONG TERM...MONDAY THROUGH THURSDAY
THE MAIN THEME: ANOMALOUS "MID-WINTER"LIKE COLD EASES WITH TEMPS
REBOUNDING TO NORMAL AS FAVORABLE PATTERN DELIVERS ANOTHER PCPN
EVENT NEXT THU NGT-FRI AND MORE IN THE OFFING AFTER THAT.
HAZARDS: NONE FORESEEN ATTM. HOWEVER OUR CURRENT MIN RH IS FCST
AROUND 25% NEXT WED. IF WINDS END UP BREEZIER THAN CURRENTLY
EXPECTED...CAN SEE THIS BEING A DAY OF ELEVATED FIRE DANGER.
BIG PICTURE: BELIEVE OVERALL PATTERN CONTINUES TO SUGGEST MORE
RAIN IN OUR FUTURE...ESPECIALLY ALONG AND E OF HWY 281. THE NAO
WILL TRANSITION TO ITS POSITIVE PHASE NEXT WEEK WITH THE PNA
REMAINING NEGATIVE. THIS PHASE CONFIGURATION WILL BE SUPPORTIVE OF
AN ERN USA RIDGE/WRN USA TROF THRU MID-MONTH AND DELIVERS AT LEAST
TWO MORE FORESEEABLE CHANCES FOR PCPN. OVERALL...TEMPS WILL
AVERAGE NEAR NORMAL THRU NEXT THU.
QPF: THE NEXT DECENT OPPORTUNITY CONTS TO BE OUTLOOKED FOR NEXT
THU NGT-FRI /15TH-16TH/. MODELS ARE STRUGGLING WITH RUN-TO-RUN
CONSISTENCY ON HOW POTENT TO KEEP THE UPPER-LEVEL SYSTEM. THE 00Z
EC ENSEMBLE MEAN SHOWS SOME SPREAD AT THE BASE OF THE TROF. THIS
HAS IMPLICATIONS FOR PCPN AMTS. IF THE UPPER SYSTEM REMAINS
OPEN...IT WILL MOVE THRU FASTER WITH LESS OF AN OPPORTUNITY FOR
PCPN. WE`RE HOPING IT REMAINS CLOSED AS WE STRUGGLE TO EVEN
MAINTAIN NORMAL PCPN AMTS. ONCE THIS SYSTEM DEPARTS...WE GET
ANOTHER QUIET INTERLUDE NEXT WEEKEND. THEN WE LOOK TO THE 19TH-
20TH FOR THE NEXT TROF AND RAIN POTENTIAL.
THE DAILY DETAILS...
MON: THE UPPER TROF/CORE OF THE COLDEST AIR DEPARTS INTO THE MS
VALLEY...ALLOWING TEMPS TO EASE UPWARD. HIGH PRES AT THE SFC.
AFTER A BONE-CHILLING START WITH MOST PLACES IN THE TEENS...A NICE
BUT STILL CHILLY DAY.
TUE: LOW AMPLITUDE SHORTWAVE RIDGE WITH STRONG HIGH PRES OVER THE
ERN USA. THIS HIGH REMAINS PARKED THERE THRU THE REST OF THE WEEK
WITH A TENDENCY TO DRIFT TOWARD NEW ENGLAND. SUNNY. TEMPS RETURN
TO NEAR NORMAL /NOW ONLY IN THE LOWER 50S/.
WED: THE TRAILING END OF A WEAK COOL FRONT MOVES THRU LATE. THIS
MAY END UP MORE OF A WINDSHIFT LINE. ALL QG FORCING/MSTR WILL BE
FAR TO THE N. DRY WITH SEASONAL/NORMAL TEMPS. MORE BREEZY AS LEE
LOW DEVELOPS OVER CO...INTENSIFYING THE GRADIENT.
THU: NW FLOW/SHORTWAVE RIDGING AS PAC TROF MOVES INTO DESERT SW.
INCREASING CLOUDS AND BREEZY.
FRI: UPPER TROF EJECTS INTO SRN/CNTRL PLAINS. RAIN LOOKING
PROBABLE AND MAY BEGIN THU NGT. GFS ENSEMBLE PCPN PROBABILITIES
ARE HIGH WITH A 70% CHANCE FOR .10 IN 24 HRS WITH POTENTIAL FOR
MORE.
COOLER WITH TEMPS PROBABLY HELD DOWN IN THE 40S.
PREV DISCUSSION... /ISSUED 1135 PM CST THU NOV 8 2012/
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION/SHORT TERM/FIRE WEATHER....BRYANT
LONG TERM HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
445 AM CST FRI NOV 9 2012
.SHORT TERM...THROUGH 12Z MONDAY. OVERNIGHT UPPER AIR ANALYSIS
INDICATES LONG WAVE TROUGHING OVER THE WESTERN AND EASTERN
CONUS...AND A RIDGE PREVAILING OVER THE CENTRAL CONUS. A CLOSED
MID LEVEL LOW IS ALSO NOTED OVER THE NORTHWESTERN CONUS...WITH
ANOTHER CLOSED MID LEVEL CIRCULATION OVER THE NORTHEASTERN CONUS.
MID AND UPPER LEVEL JET ENERGY EXTENDS FROM CALIFORNIA...NORTHEAST
INTO THE NORTHERN PLAINS AND SOUTH CENTRAL CANADA...AND THEN
SOUTHEAST ACROSS THE OHIO VALLEY AND ON INTO THE SOUTHEASTERN
CONUS. TROPOSPHERIC FLOW IS NOT OVERLY STRONG NEAR OUR AREA AS A
RESULT...MAXING OUT AT AROUND 50KTS AT VARIOUS POINTS BETWEEN
500MB AND 200MB PER 00Z SOUNDING DATA FROM KLBF. WATER VAPOR
IMAGERY CLEARLY SHOWS THE CLOSED MID LEVEL LOWS OVER THE
NORTHWESTERN AND NORTHEASTERN CONUS. INCREASING VALUES OF MID
LEVEL MOISTURE ARE ALSO NOTED ON WATER VAPOR IMAGERY ADVECTING
NORTHEAST ALONG THE FRONT OF THE LONG WAVE TROUGH...INTO THE ROCKY
MOUNTAIN RANGE AND PLAINS. SOME OF THIS MID LEVEL MOISTURE IS
PROMOTING INCREASING MID TO HIGH LEVEL CLOUD COVER OVER PORTIONS
OF THE CENTRAL PLAINS. AT THE SURFACE A STATIONARY BOUNDARY IS
NOTED EXTENDING FROM WESTERN IOWA...SOUTHWEST INTO NORTHEASTERN
KANSAS AND ON INTO SOUTHEASTERN COLORADO. THE LOW LEVEL WIND FIELD
ACROSS OUR AREA REMAINS FROM THE NORTH AS A RESULT...BUT IS FAIRLY
LIGHT AT AROUND 5KTS. IN ADDITION TO THE AFOREMENTIONED MID TO
HIGH LEVEL CLOUDS BEGINNING TO WORK INTO THE REGION...SATELLITE
IMAGERY ALSO INDICATES A STRATUS DECK OVER MUCH OF THE NORTHERN
PLAINS...WITH THIS DECK MOVING SOUTH/SOUTHEAST AT AROUND 20KTS AND
ALREADY INFILTRATING PORTIONS OF CENTRAL NEBRASKA.
GUIDANCE FROM THE NAM...RAP...AND OPERATIONAL GFS ALL SUGGEST
ISENTROPIC UPGLIDE AND SATURATION...PRIMARILY ALONG THE 290-295K
SURFACES...WILL CONTINUE TO PROMOTE STRATUS OVER PORTIONS OF THE
REGION THROUGH MIDDAY. THERE IS SOME UNCERTAINTY AS TO HOW FAR
SOUTH THIS STRATUS DECK WILL MOVE ACROSS OUR CWA. THE OPERATIONAL
GFS REMAINS THE MOST AGGRESSIVE IN BRINGING THE DECK ACROSS OUR
ENTIRE CWA...WHILE THE NAM AND RAP BOTH SUGGEST THE NORTHERN HALF
OF OUR CWA WILL BE THE ONLY LOCATIONS TO OBSERVE THIS STRATUS.
SATELLITE IMAGERY INDICATES THE STRATUS DECK HAS SLOWED THROUGH
THE PAST 2-3 HOURS AND IT NOW SEEMS UNLIKELY THIS STRATUS WILL
MAKE IT TO OUR KANSAS COUNTIES BY 12Z...WHICH IS WHAT THE
OPERATIONAL GFS SUGGESTS. GIVEN THIS...OPTED TO PLAY CLOSER TO NAM
AND RAP GUIDANCE BY KEEPING THE FORECAST STRATUS PRIMARILY OVER
THE NORTHERN HALF OF THE CWA. GUIDANCE FROM THE NAM AND RAP ALSO
SUGGEST THE LOW LEVEL BAROCLINIC ZONE TO OUR SOUTH/SOUTHEAST WILL
LIFT NORTH AS A WARM FRONT TODAY...THUS CARRYING THE PRIMARY AXIS
OF ISENTROPIC UPGLIDE FARTHER NORTH WHICH SHOULD HELP CLEAR THE
STRATUS FROM MUCH OF OUR CWA BY MIDDAY. ALTHOUGH THE INCREASING
MID AND HIGH LEVEL CLOUDS MAY KEEP TEMPERATURES FROM MEETING THEIR
FULL DIURNAL POTENTIAL TODAY...THERE SHOULD BE ENOUGH DIABATIC
HEATING FOR 20-25 DEGREE TEMPERATURE RISES WHICH SHOULD PRESENT
AFTERNOON HIGHS GENERALLY IN THE 60S AND 70S...WITH THE ONLY
EXCEPTION BEING ACROSS OUR FAR NORTH WHERE THE STRATUS MAY KEEP
TEMPERATURES IN THE 50S.
THE BIG WEATHER STORY CONTINUES TO REVOLVE AROUND THE INCOMING
SYSTEM FOR THIS WEEKEND. GUIDANCE CONTINUES TO SUGGEST THE MID
LEVEL LOW...CURRENTLY OVER THE NORTHWESTERN CONUS...WILL OPEN UP
INTO A WAVE AND MOVE EAST INTO THE CENTRAL CONUS TONIGHT THROUGH
SUNDAY. AS THE MID LEVEL TROUGH APPROACHES FROM THE
WEST...RESULTANT SURFACE CYCLOGENESIS IS EXPECTED TO COMMENCE OVER
THE HIGH PLAINS OF NORTHEASTERN COLORADO OVERNIGHT TONIGHT. THIS
SURFACE LOW IS THEN EXPECTED TO QUICKLY EJECT NORTHEAST ACROSS THE
CENTRAL PLAINS AS THE MID LEVEL TROUGH AXIS APPROACHES OUR AREA
FROM THE WEST. AS THE SURFACE LOW MOVE NORTHEAST...AN ASSOCIATED
COLD FRONT IS EXPECTED TO SWEEP ACROSS OUR AREA SATURDAY AFTERNOON
INTO SATURDAY NIGHT.
QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST MID LEVEL THERMAL ADVECTION AHEAD OF THE MID LEVEL TROUGH
AXIS...WORKING IN CONCERT WITH LOW LEVEL CONVERGENCE ALONG THE LOW
LEVEL BAROCLINIC ZONE...WILL PROVIDE SUFFICIENT LIFT FOR
CONVECTIVE INITIATION NEAR THE BAROCLINIC ZONE SATURDAY AFTERNOON.
AT THIS TIME IT APPEARS THIS CONVECTION WILL INITIALIZE IN THE
VICINITY OF A LINE EXTENDING FROM FULLERTON...TO GRAND ISLAND...TO
PHILLIPSBURG. INCREASED VALUES OF LOW LEVEL MOISTURE AHEAD OF THE
LOW LEVEL BAROCLINIC ZONE...ALONG WITH INCREASING MID LEVEL LAPSE
RATES WITH THE APPROACH OF THE MID LEVEL TROUGH AXIS...SHOULD BE
SUFFICIENT ENOUGH TO PROVIDE 0-1MLCAPE VALUES ON THE ORDER OF
1000J/KG PER THE NAM AND OPERATIONAL GFS. IN ADDITION TO THE
POTENTIAL INSTABILITY...INCREASING MID AND UPPER LEVEL JET ENERGY
WILL ALSO LIKELY PROVIDE DEEP LAYER BULK SHEAR VALUES IN EXCESS
50KTS ACROSS MUCH OF THE REGION. ALSO...FORECAST PROXIMITY
SOUNDINGS FROM ACROSS THE CWA...PER THE NAM...SUGGEST A VEERING
LOW LEVEL WIND PROFILE FOR LOCATIONS STILL AHEAD OF THE LOW LEVEL
BAROCLINIC ZONE...WITH THE NAM ALSO SUGGESTING 0-1KM SRH WILL
APPROACH 300M^2/S^2 ACROSS EAST/SOUTHEASTERN PORTIONS OF OUR CWA.
NOW...INCREASING MID AND HIGH LEVEL CLOUDS WILL LIKELY KEEP
DIABATIC HEATING DOWN A TOUCH THROUGH MUCH OF THE DAY WHICH WILL
HELP SUSTAIN SOMETHING OF A CAPPING INVERSION...WHICH MEANS
INITIAL CONVECTIVE DEVELOPMENT COULD BE IN THE FORM OF A FEW
DISCRETE CELLS IN THE VICINITY OF THE LOW LEVEL BAROCLINIC ZONE.
GIVEN THE VERY STRONG DEEP LAYER BULK SHEAR...SUPER CELL
DEVELOPMENT WILL BE MORE THAN POSSIBLE AND GIVEN THIS...WILL
CONTINUE OUTLOOKING LARGE HAIL IN THE HWO. ADDITIONAL CONVECTIVE
DEVELOPMENT ALONG THE BAROCLINIC ZONE COULD THEN POTENTIALLY
EVOLVE INTO A QLCS WITH STRONG OUTFLOW WINDS AT THE SURFACE
REMAINING VERY POSSIBLE. WILL CONTINUE TO CARRY SEVERE
THUNDERSTORM WIND WORDING IN HWO AS WELL. FINALLY...GIVEN THE LOW
LEVEL SHEAR AS INDICATED BY THE NAM...WILL ALSO GO AHEAD AND
MENTION ISOLATED TORNADIC DEVELOPMENT IN ASSOCIATION WITH THE
INITIAL CONVECTION DURING THE LATE AFTERNOON HOURS.
STRONG WINDS WILL NOT ONLY BE A THREAT WITH AFTERNOON AND EVENING
THUNDERSTORM ACTIVITY ON SATURDAY...BUT STRONG SYNOPTIC WINDS WILL
ALSO BE OBSERVED ACROSS MUCH OF THE CWA SATURDAY. AS SURFACE
CYCLOGENESIS CONTINUES ACROSS THE HIGH PLAINS SATURDAY...THE LOW
LEVEL PRESSURE GRADIENT IS EXPECTED TO INTENSIFY GREATLY HEADING
INTO SATURDAY AFTERNOON...ESPECIALLY ACROSS THE SOUTHEASTERN ONE-
HALF OF THE CWA. IN ADDITION...FORECAST PROXIMITY SOUNDINGS FROM
ACROSS OUR CWA PER THE NAM AND OPERATIONAL GFS SUGGEST BOUNDARY
LAYER MIXING TO BETWEEN 850MB AND 800MB WILL BE REALIZED...WHICH
IS WHERE ~50KT WINDS WILL BE WAITING FOR TRANSPORT TO THE SURFACE.
INTERESTING TO NOTE THAT BOTH MET AND MAV GUIDANCE SUGGEST
PORTIONS OF OUR CWA WILL HIT WIND ADVISORY CRITERIA AT SOME POINT
DURING THE DAY SATURDAY...WITH MAV GUIDANCE SUGGESTING OUR
SOUTHWEST WILL HIT BETWEEN 18Z AND 21Z...AND THE NAM SUGGESTING
OUR SOUTHEAST WILL HIT CLOSER TO 00Z. RATHER THAN BLANKET A
MAJORITY OF OUR CWA WITH WIND ADVISORY WINDS...OPTED TO KEEP WINDS
JUST UNDER WIND ADVISORY ACROSS THE SOUTHEASTERN HALF OF THE CWA
WITH THE HOPES THAT WE WILL BE ABLE TO FINE-TUNE THE WIND FORECAST
AND INCREASE WINDS SOMEWHAT...INTO WIND ADVISORY CRITERIA...FOR
PORTIONS OF THE CWA ONCE THAT FORECAST BECOMES MORE CLEAR. WILL GO
AHEAD AND CONTINUE TO CARRY STRONG SYNOPTIC WIND WORDING IN THE
HWO FOR SATURDAY AFTERNOON. STRONG SYNOPTIC WINDS WILL NOT ONLY BE
A THREAT SATURDAY AFTERNOON...BUT WILL ALSO BE POSSIBLE SATURDAY
NIGHT INTO EARLY SUNDAY MORNING AFTER THE LOW LEVEL BAROCLINIC
ZONE CLEAR THE AREA. INTENSE LOW LEVEL PRESSURE RISES POST-FROPA
WILL PROMOTE YET ANOTHER INCREASE IN THE LOW LEVEL PRESSURE
GRADIENT ACROSS THE CWA 00Z-12Z SUNDAY...WITH GUIDANCE SUGGESTING
~20KT SUSTAINED WINDS WILL BE REALIZED ACROSS MUCH OF THE AREA.
WILL GO AHEAD AND CONTINUE CARRYING STRONG SYNOPTIC WIND WORDING
IN THE HWO FOR SATURDAY NIGHT/SUNDAY MORNING AS A RESULT.
WITH THE INFILTRATION OF A MUCH COLDER LOW LEVEL
AIRMASS...FORECAST PROXIMITY SOUNDINGS FROM THE ACROSS THE CWA PER
THE NAM...OPERATIONAL GFS AND EC ALL SUGGEST THE LOWER TROPOSPHERE
WILL BECOME SUPPORTIVE FOR SNOW ACROSS MUCH OF THE CWA SATURDAY
NIGHT INTO SUNDAY MORNING. AT THIS TIME IT APPEARS ANY
PRECIPITATION BEHIND THE LOW LEVEL BAROCLINIC WILL REMAIN FAIRLY
LIGHT ACROSS OUR CWA...THUS ANY SNOWFALL ACCUMULATIONS ACROSS OUR
CWA SHOULD REMAIN UNDER AN INCH. LOCATIONS WEST OF HIGHWAY 281 AND
NORTH OF I-80...WHICH IS WHERE THE LOW LEVEL COLD AIR ADVECTION
WILL BE FIRST TO INFILTRATE...SEEM MOST LIKELY TO OBSERVE THE MOST
SNOWFALL ACCUMULATION. IT IS WORTH NOTING THAT A FEW FORECAST
PROXIMITY SOUNDINGS SUGGEST A BRIEF PERIOD OF SLEET NEAR THE TRI-
CITIES AREA AS THE TRANSITION FROM RAIN TO SNOW BEGINS...BUT GIVEN
THE UNCERTAINTY AND BREVITY OF ANY SUCH POTENTIAL ACTIVITY...OPTED
TO HOLD OFF FROM MENTIONING THIS IN THE FORECAST FOR THE TIME
BEING.
FINALLY...TEMPERATURES LOOK TO FALL OFF DRAMATICALLY POST-FROPA
HEADING INTO SATURDAY NIGHT...AND WITH CONTINUED LOW LEVEL COLD
AIR ADVECTION AND LINGERING CLOUD COVER DURING THE DAY
SUNDAY...ITS DOUBTFUL TEMPERATURES WILL GO MUCH OF ANYWHERE DURING
THE DAY SUNDAY. LOWS IN THE MID 20S TO MID 30S ARE CURRENTLY
FORECAST FOR SATURDAY NIGHT...WITH TEMPERATURES STRUGGLING THROUGH
THE 30S DURING THE DAY SUNDAY. THE PASSAGE OF THE SURFACE RIDGE
AND THE INTRODUCTION OF LOW LEVEL RETURN FLOW SHOULD THEN PRESENT
A WARMING TREND TO FINISH OUT THE SHORT TERM FORECAST PERIOD.
.LONG TERM...MONDAY THROUGH THURSDAY
THE MAIN THEME: ANOMALOUS "MID-WINTER"LIKE COLD EASES WITH TEMPS
REBOUNDING TO NORMAL AS FAVORABLE PATTERN DELIVERS ANOTHER PCPN
EVENT NEXT THU NGT-FRI AND MORE IN THE OFFING AFTER THAT.
HAZARDS: NONE FORESEEN ATTM. HOWEVER OUR CURRENT MIN RH IS FCST
AROUND 25% NEXT WED. IF WINDS END UP BREEZIER THAN CURRENTLY
EXPECTED...CAN SEE THIS BEING A DAY OF ELEVATED FIRE DANGER.
BIG PICTURE: BELIEVE OVERALL PATTERN CONTINUES TO SUGGEST MORE
RAIN IN OUR FUTURE...ESPECIALLY ALONG AND E OF HWY 281. THE NAO
WILL TRANSITION TO ITS POSITIVE PHASE NEXT WEEK WITH THE PNA
REMAINING NEGATIVE. THIS PHASE CONFIGURATION WILL BE SUPPORTIVE OF
AN ERN USA RIDGE/WRN USA TROF THRU MID-MONTH AND DELIVERS AT LEAST
TWO MORE FORESEEABLE CHANCES FOR PCPN. OVERALL...TEMPS WILL
AVERAGE NEAR NORMAL THRU NEXT THU.
QPF: THE NEXT DECENT OPPORTUNITY CONTS TO BE OUTLOOKED FOR NEXT
THU NGT-FRI /15TH-16TH/. MODELS ARE STRUGGLING WITH RUN-TO-RUN
CONSISTENCY ON HOW POTENT TO KEEP THE UPPER-LEVEL SYSTEM. THE 00Z
EC ENSEMBLE MEAN SHOWS SOME SPREAD AT THE BASE OF THE TROF. THIS
HAS IMPLICATIONS FOR PCPN AMTS. IF THE UPPER SYSTEM REMAINS
OPEN...IT WILL MOVE THRU FASTER WITH LESS OF AN OPPORTUNITY FOR
PCPN. WE`RE HOPING IT REMAINS CLOSED AS WE STRUGGLE TO EVEN
MAINTAIN NORMAL PCPN AMTS. ONCE THIS SYSTEM DEPARTS...WE GET
ANOTHER QUIET INTERLUDE NEXT WEEKEND. THEN WE LOOK TO THE 19TH-
20TH FOR THE NEXT TROF AND RAIN POTENTIAL.
THE DAILY DETAILS...
MON: THE UPPER TROF/CORE OF THE COLDEST AIR DEPARTS INTO THE MS
VALLEY...ALLOWING TEMPS TO EASE UPWARD. HIGH PRES AT THE SFC.
AFTER A BONE-CHILLING START WITH MOST PLACES IN THE TEENS...A NICE
BUT STILL CHILLY DAY.
TUE: LOW AMPLITUDE SHORTWAVE RIDGE WITH STRONG HIGH PRES OVER THE
ERN USA. THIS HIGH REMAINS PARKED THERE THRU THE REST OF THE WEEK
WITH A TENDENCY TO DRIFT TOWARD NEW ENGLAND. SUNNY. TEMPS RETURN
TO NEAR NORMAL /NOW ONLY IN THE LOWER 50S/.
WED: THE TRAILING END OF A WEAK COOL FRONT MOVES THRU LATE. THIS
MAY END UP MORE OF A WINDSHIFT LINE. ALL QG FORCING/MSTR WILL BE
FAR TO THE N. DRY WITH SEASONAL/NORMAL TEMPS. MORE BREEZY AS LEE
LOW DEVELOPS OVER CO...INTENSIFYING THE GRADIENT.
THU: NW FLOW/SHORTWAVE RIDGING AS PAC TROF MOVES INTO DESERT SW.
INCREASING CLOUDS AND BREEZY.
FRI: UPPER TROF EJECTS INTO SRN/CNTRL PLAINS. RAIN LOOKING
PROBABLE AND MAY BEGIN THU NGT. GFS ENSEMBLE PCPN PROBABILITIES
ARE HIGH WITH A 70% CHANCE FOR .10 IN 24 HRS WITH POTENTIAL FOR
MORE.
COOLER WITH TEMPS PROBABLY HELD DOWN IN THE 40S.
&&
.PREV DISCUSSION... /ISSUED 1135 PM CST THU NOV 8 2012/
AVIATION...06Z KGRI TAF. VFR CONDITIONS TO CONTINUE THROUGH
10Z...WITH PREVAILING MVFR CONDITIONS THEN FORECAST 10Z-16Z.
PERIODIC IFR CONDITIONS WILL ALSO BE POSSIBLE 12Z-16Z. VFR
CONDITIONS ARE FORECAST 16Z ONWARD. SATELLITE IMAGERY INDICATES
STRATUS OVER SOUTH DAKOTA AND NORTHERN NEBRASKA...MOVING
SOUTH/SOUTHEAST AT AROUND 35KTS. AS OF 05Z THIS STRATUS HAD
REACHED POINTS AS FAR SOUTH AS KONL AND KANW AND IF THESE TRENDS
CONTINUE...STRATUS SHOULD INFILTRATE KGRI AROUND 10Z. PREVAILING
MVFR CONDITIONS HAVE BEEN INSERTED INTO THE TAF AS A RESULT. SOME
LOCATIONS WITHIN THIS STRATUS DECK HAVE ALSO REPORTED IFR
CEILINGS...THUS IS WHY PERIODIC IFR CONDITIONS HAVE ALSO BEEN
INSERTED. DIFFERENT SETS OF GUIDANCE OFFER DIFFERING SOLUTIONS AS
TO WHEN VFR CONDITIONS WILL BE RESTORED AT KGRI...BUT A BLEND OF
THIS GUIDANCE...WITH GREATER WEIGHT PLACED ON MAV/GFS GUIDANCE
WHICH HAS SEEMED TO HAVE A BETTER HANDLE ON THE EVOLVING SITUATION
THROUGH THE PAST 24 HOURS...WOULD SUGGEST MVFR CONDITIONS WILL
PREVAIL AT KGRI THROUGH MID TO LATE MORNING...WITH VFR CONDITIONS
EXPECTED THEREAFTER. THE SURFACE WIND WILL REMAIN GENERALLY LIGHT
AND VARIABLE THROUGH THE TAF PERIOD...WHICH MAY ALSO ALLOW FOR
PATCHY FOG DEVELOPMENT TONIGHT INTO FRIDAY MORNING. VISIBILITY
RESTRICTION...TO AROUND 5SM IN BR...HAS ALSO BEEN INSERTED INTO
THE TAF AS A RESULT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM/AVIATION...BRYANT
LONG TERM...HALBLAUB
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1109 AM MST FRI NOV 9 2012
.UPDATE...WILL BE MAKING SOME GENERALLY SMALL CHANGES...A LITTLE
COOLER FROM NORTH DENVER NORTHWARD AS MIXING LIMITED IN THIS AREA
WITH LIGHT NORTH TO NORTHEAST WINDS. MUCH MILDER SOUTH OF DENVER
AND FARTHER TO THE EAST. MILD IN THE MOUNTAINS WITH A SLIGHT
DECREASE IN THE PRECIPITATION POSSIBILITIES THERE.
&&
.AVIATION...KIND OF RARE TOTALLY CALM WIND AT ALL THE LLWS SITES
FOR DIA THIS MORNING FOR AWHILE. KEPT A LIGHT ENE WIND FOR TODAY
BUT WILL NEED TO WATCH AS THERE ARE STRONGER WSW WINDS TO OUR
SOUTH. A NICE FINE LINE ON RADAR MARKS THIS BOUNDARY. HRRR WINDS
KEEP THIS TO THE SOUTH UNTIL THIS EVENING AND OTHER MODELS
GENERALLY AGREE BUT WILL KEEP AN EYE ON IT.
&&
.PREV DISCUSSION... /ISSUED 407 AM MST FRI NOV 9 2012/
SHORT TERM...THINGS ARE STILL ON COURSE FOR THE LAST WARM DAY OF
THE CURRENT STRETCH ACROSS NORTHEAST COLORADO. MODERATE SOUTHWEST
FLOW ALOFT WILL CONTINUE OVER THE STATE TODAY AS A VIGOROUS UPPER
TROUGH MOVES INTO THE GREAT BASIN. MOISTURE AHEAD OF THIS TROUGH
WILL BE MOVING OVER COLORADO THROUGH TODAY...BUT EASTERN COLORADO
SHOULD ONLY SEE HIGH LEVEL CLOUDINESS. DEEPER MOISTURE WILL REACH
THE MOUNTAINS EARLY THIS EVENING...WITH AREAS OF RAIN AND SNOW
DEVELOPING AND THEN CHANGING TO SNOW BY MIDNIGHT. THROUGH 12Z
TOMORROW MORNING...THE MOUNTAINS SHOULD BE THE ONLY AREAS TO
RECEIVE ANY PRECIPITATION. AT THE SURFACE...MODELS ARE NOW SHOWING
THE STRONGEST SURFACE CYCLOGENESIS OVER SOUTHERN WYOMING THROUGH
06Z AND THEN DROPPING INTO NORTHEAST COLORADO BY 12Z BEFORE MOVING
INTO WESTERN NEBRASKA. AS THE SURFACE DEVELOPMENT REMAINS TO OUR
NORTH...FLOW OFF THE MOUNTAINS AND FRONT RANGE FOOTHILLS WILL BE
DOWNSLOPING AND MAINLY DRY. WINDS ON THE PLAINS SHOULD REMAIN OUT
OF THE SOUTH. ANY SIGNIFICANT COOLING TO THE AIRMASS WILL NOT
OCCUR UNTIL AFTER THE SURFACE LOW DROPS INTO NORTHEAST COLORADO.
THAT WILL LEAVE US WITH UNSEASONABLY WARM TEMPERATURES AGAIN
TODAY...IN SPITE OF PERIODS OF MID AND HIGH LEVEL CLOUDINESS. LOW
TEMPERATURES TONIGHT WILL ALSO BE MODERATED BY THE DOWNSLOPING
WINDS FEEDING INTO THE DEVELOPING SURFACE LOW TO OUR NORTH. MODEL
QPF FORECASTS IN THE MOUNTAINS ARE PRETTY LIGHT THROUGH 12Z SO NO
HIGHLIGHTS WILL BE NEEDED FOR THE FIRST TWO PERIODS OF THE
FORECAST.
LONG TERM...AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE RGN SAT
INTO SUN. THE FLOW ALOFT WILL BE SWLY ON SAT AND THEN BECOME MORE
NWLY LATE SAT NIGHT INTO SUN AS THE TROUGH AXIS MOVES ACROSS.
THERE WILL BE PLENTY OF MOISTURE IN THE MTNS ALONG WITH DECENT
INSTABILITY ALONG WITH SOME MINOR QG ASCENT. THUS WILL SEE SOME
SNOW WITH THE BEST ACCUMULATIONS THRU SAT AFTN IN ZN 31 WHERE
AMOUNTS MAY REACH ADVISORY CRITERIA. BY SAT NIGHT INTO SUN AS THE
FLOW ALOFT BECOMES MORE NWLY THE REST OF THE MTNS WILL RECEIVE
SOME ACCUMULATIONS WITH AMOUNTS GENERALLY BLO ADVISORY CRITERIA.
EAST OF THE MTNS THERE ARE LARGE DIFFERENCES BETWEEN THE NAM...GFS
AND ECMWF WITH RESPECT TO HOW MUCH PCPN WILL OCCUR. THE GFS AND TO
SOME EXTENT THE ECMWF SHOW BETTER UPSLOPE COMPONENT FM LATE SAT
AFTN THRU SAT NIGHT WITH DECENT MOISTURE WHILE THE NAM IS DRIER
AND HAS MORE OF A DOWNSLOPE COMPONENT. AS A RESULT THE ECMWF AND
GFS HAVE MORE PCPN WHILE THE NAM BASICALLY HAS NO PCPN EXCEPT FOR
A SMALL AREA OVER THE NERN PLAINS. CONSIDERING THE POSITION OF THE
UPPER LEVEL JET AND STEEP LAPSE RATES NR 9 C/KM SAT EVENING ALONG
WITH POTENTIAL FOR BANDED PCPN I FIND IT HARD TO BELIEVE THERE
WILL NOT BE ANY PCPN AS NAM DEPICTS. THUS WILL KEEP LIKELY POPS IN
THE FCST SAT NIGHT OVER NERN CO. IF SOUNDINGS ARE MOIST ADIABATIC
AS SHOWN BY GFS THEN A BURST OF HEAVIER CONVECTIVE SNOW WILL
CERTAINLY BE POSSIBLE ACROSS PORTIONS OF NERN CO. THE GFS HAS A
BULLSEYE OVER DENVER WHILE THE ECMWF IS A BIT FURTHER EAST. AS FOR
TEMPS TIMING OF FNT COMING INTO NERN CO WILL HAVE AN AFFECT ON
HIGHS. RIGHT NOW THE GFS HAS IT MOVING INTO DENVER AROUND 18Z AND
THEN STALLING OVER THE PLAMER DIVIDE DUE TO STRONGER SWLY LOW LVL
FLOW. NORTH OF THE FNT HIGHS WILL ONLY BE IN THE 40S WHILE SOUTH
OF IT HIGHS COULD REACH THE LOWER TO MID 60S ACROSS LINCOLN
COUNTY.
BY SUN AFTN THE UPPER LEVEL TROUGH WILL MOVE AWAY FM THE AREA WITH
NWLY FLOW ALOFT. MOISTURE WILL LINGER IN THE MTNS THRU SUN EVENING
SO WILL KEEP SOME POPS IN THRU MIDNIGHT. ACROSS NERN CO IT LOOKS
LIKE PCPN SHOULD END SUN MORNING. HIGHS ON SUN WILL BE COLD WITH
READINGS MAINLY IN THE UPPER 20S TO LOWER 30S ACROSS NERN CO. FOR
MON DRY NWLY FLOW ALOFT WILL BE OVER THE AREA WITH NO PCPN
EXPECTED. HIGHS SHOULD RISE BACK INTO THE LOWER TO MID 40S OVER
THE PLAINS.
FOR TUE THE FLOW ALOFT WILL BECOME MORE WLY WITH DRY CONDITIONS.
TEMPS SHOULD CONTINUE TO RISE A FEW MORE DEGREES WITH READINGS IN
THE UPPER 40S TO LOWER 50S ACROSS NERN CO. BY WED THE FLOW ALOFT
WILL BECOME MORE SWLY AS ANOTHER UPPER LEVEL TROUGH DEVELOPS OVER
THE WRN US. SOME MID AND HIGH LEVEL MOISTURE WILL SPREAD ACROSS
THE AREA BUT NO PCPN IS EXPECTED. HIGHS SHOULD RISE BACK INTO THE
50S OVER NERN CO BASED ON LATEST 850-700 MB TEMPS.
BY THU THERE ARE LARGE DIFFERENCES BETWEEN THE ECMWF AND GFS IN
HANDLING OF THE NEXT UPPER LEVEL TROUGH. THE GFS MOVES THE NEXT
TROUGH ACROSS THE AREA LATE THU INTO EARLY FRI WHILE THE ECMWF IS
A DAY SLOWER WITH THIS FEATURE. AT THIS POINT HARD TO SAY WHICH
SOLUTION IS RIGHT SO WILL JUST MENTION A SLIGHT CHC OF SHOWERS IN
THE MTNS AND KEEP HIGHS NEAR SEASONAL LEVELS.
AVIATION...DENVER AREA AIRPORTS WILL SEE INCREASING CLOUDS ALOFT
THROUGH THE DAY...BUT CEILINGS SHOULD REMAIN WELL ABOVE 10
THOUSAND FEET UNTIL LATER TONIGHT. WINDS WILL HAVE A SOUTHERLY
COMPONENT THROUGH TONIGHT AS A SURFACE LOW PRESSURE AREA IS
EXPECTED TO INTENSIFY OVER SOUTHERN WYOMING LATER TODAY. CEILINGS
WILL BEGIN TO DECREASE DURING THE PRE-DAWN HOURS TOMORROW MORNING
WITH PRECIPITATION DEVELOPING AFTER 12Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 AM SATURDAY TO 5 AM MST SUNDAY
FOR COZ031.
&&
$$
SHORT TERM...SZOKE
LONG TERM....RPK
AVIATION...SZOKE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
251 PM MST FRI NOV 9 2012
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 224 PM MST FRI NOV 9 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW BROAD RIDGE ACROSS THE
EASTERN US CENTERED OVER THE OHIO RIVER VALLEY. UPSTREAM A TROUGH
EXTENDS SOUTH ACROSS THE WESTERN US WITH A CLOSED CENTER OVER
WASHINGTON STATE. SW FLOW IS IN PLACE OVER THE CWA BETWEEN THESE
FEATURES. AT THE SURFACE A STATIONARY FRONT CURRENTLY EXTENDS
ACROSS EASTERN COLORADO TO SOUTHWEST KANSAS.
A WARM FRONT WILL LIFT ACROSS THE CWA TONIGHT WITH BREEZY SW WINDS
AND WARMER H85 TEMPS RESULTING IN OVERNIGHT LOWS IN 40S FOR MOST
LOCATIONS. THE TROUGH OVER THE WESTERN US WILL BEGIN TO SHIFT EAST
ACROSS THE INTER-MOUNTAIN WEST THROUGH SUNDAY WITH AN ASSOCIATED
COLD FRONT MOVING SOUTHEAST TOWARDS THE CWA SATURDAY AFTERNOON.
AHEAD OF THIS FRONT SURFACE PRESSURE GRADIENT WILL BE INCREASING
FROM THE S-SW WITH H85 JET BETWEEN 40-45KT. CONFIDENCE IS HIGHEST
THAT WIND ADVISORY CRITERIA WILL BE MET ACROSS THE SOUTHEAST
CWA...THOUGH IF H7 WINDS WERE ABLE TO MIX DOWN WE COULD APPROACH
WARNING CRITERIA. IM NOT SURE WE WILL SEE 3HR OF SUSTAINED
CRITERIA IN SHERMAN COUNTY AND CHEYENNE/KIT CARSON COLORADO
COUNTIES. HOWEVER...WE SHOULD SEE GUSTS AROUND 45 MPH THERE SO I
WAS COMFORTABLE INCLUDING THEM IN THE ADVISORY.
AHEAD OF THE COLD FRONT A DRY LINE WILL SET UP ACROSS CENTRAL
KANSAS WITH THUNDERSTORMS DEVELOPING AHEAD OF THIS FEATURE. ALL
CURRENT GUIDANCE IS SHOWING THE DRY LINE REMAINING EAST OF THE
CWA...SO I DELAYED ONSET OF PRECIP IN THE EAST UNTIL FROPA AND
LEFT THUNDER OUT OF FORECAST. BEST CHANCE FOR PRECIP SHOULD BE
ACROSS THE NORTHWEST ALONG AND BEHIND THE COLD FRONT WHERE BEST
LARGE SCALE ASCENT AND GOOD MOISTURE ADVECTION WILL SPREAD INTO
CWA BY 00Z.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 240 PM MST FRI NOV 9 2012
THE COLD FRONT WILL BLAST THROUGH THE AREA SATURDAY EVENING AND
NIGHT. MODELS CONTINUE TO SHOW PRECIPITATION DEVELOPING BEHIND THE
FRONT. AS THE PRECIPITATION AND COLD AIR CONTINUE TO MOVE IN...A
CHANGE FROM RAIN TO SNOW IS EXPECTED. MOST MODELS...THE
CANADIAN...THE EUROPEAN AND THE NAM TO BE SPECIFIC...HAVE INCREASED QPF
AMOUNTS FROM PREVIOUS RUNS WHILE THE GFS HAS DECREASED QPF
AMOUNTS. THEREFORE...SLIGHTLY HIGHER PRECIPITATION AMOUNTS ARE NOW
FORECAST. THIS LEADS TO SNOWFALL AMOUNTS RANGING FROM A TRACE IN
MOST AREAS TO AS HIGH AS AN INCH IN YUMA COUNTY COLORADO. HPC IS
SUGGESTING TOTALS COULD BE AS HIGH AS 2 INCHES IN NORTHERN YUMA
COUNTY AND WOULD NOT BE SURPRISED IF THIS HAPPENED.
A COLD SURFACE HIGH PRESSURE SYSTEM WILL BUILD IN ON SUNDAY. THIS
WILL KEEP TEMPERATURES QUITE CHILLY WITH HIGHS IN THE 30S. BREEZY
NORTH WINDS WILL CONTINUE ON SUNDAY BEHIND THE COLD FRONT. A FEW
ADDITIONAL SNOW SHOWERS ARE POSSIBLE IN EASTERN COLORADO ON SUNDAY
MORNING...WITH ALL THE PRECIPITATION CLEARING OUT BY SUNDAY
AFTERNOON.
THE COLDEST NIGHT OF THE FALL IS EXPECTED ON SUNDAY NIGHT. THE COLD
SURFACE HIGH PRESSURE WILL SETTLE IN FOR THE NIGHT. IN
ADDITION...THE WINDS WILL WEAKEN AND SKIES WILL CLEAR. THIS WILL
ALLOW FOR TEMPERATURES TO DROP INTO THE TEENS SUNDAY NIGHT. EVEN
WITH LIGHT WINDS...WIND CHILLS ARE CURRENTLY FORECAST TO FALL INTO
THE SINGLE DIGITS BY MONDAY MORNING.
A WEAK UPPER LEVEL RIDGE OF HIGH PRESSURE WILL BUILD INTO THE
TRI-STATE AREA ON MONDAY. THIS WILL BLOCK ANY WEATHER SYSTEMS
FROM MOVING IN UNTIL THE END OF THE WEEK. THEREFORE...NO RAIN IS
EXPECTED THROUGH AT LEAST WEDNESDAY. TEMPERATURES WILL BE BELOW
NORMAL FOR MONDAY. HOWEVER...A WARMING TREND IS EXPECTED FOR THE
MIDDLE OF THE WEEK AS WINDS RETURN FROM THE SOUTH.
MODEL AGREEMENT FROM YESTERDAY ON THE NEXT WEATHER SYSTEM HAS TURNED
INTO COMPLETE MODEL DISAGREEMENT. THE CANADIAN MODEL SHOWS AN
UPPER LEVEL TROUGH MOVING INTO THE REGION WITH A LEE TROUGH DEVELOPING
ON THURSDAY MORNING. THE CANADIAN MODEL SHOWS A LARGE AREA OF
PRECIPITATION JUST TO THE NORTH OF THE LEE TROUGH OVER
NEBRASKA...WYOMING AND SOUTH DAKOTA. THE EUROPEAN MODEL IS FAIRLY
CONSISTENT WITH YESTERDAYS 12Z MODEL RUN WITH A LONGWAVE TROUGH
MOVING INTO THE AREA THURSDAY NIGHT INTO FRIDAY. THE EUROPEAN
MODEL HAS PRECIPITATION DEVELOPING AHEAD OF THE TROUGH OVER THE
TRI-STATE THURSDAY NIGHT THROUGH FRIDAY. THE GFS MODEL IS NOW
FORECASTING A VERY WEAK TROUGH MOVING THROUGH LATER...NOW ON
SATURDAY INSTEAD OF FRIDAY. THE GFS MODEL AMPLIFIES THIS TROUGH TO
THE EAST AND DEVELOPS PRECIPITATION AHEAD OF IT...THUS MISSING THE
TRI-STATE AREA. IT IS HARD TO DECIDE WHICH MODEL IS CORRECT AT THE
MOMENT...SO JUST WENT WITH THE MODEL BLEND. THIS SUGGESTED SLIGHT
CHANCE AND LOW END CHANCE POPS FOR THURSDAY NIGHT THROUGH FRIDAY.
AT THE PRESENT TIME...MODELS ARE NOT SHOWING ANOTHER STRONG COLD
FRONT MOVING IN BEHIND THE NEXT WEATHER SYSTEM SO HAVE GONE WITH A
PERSISTENCE FORECAST OF NEAR NORMAL TEMPERATURES FOR THE END OF
THE WORK WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1050 AM MST FRI NOV 9 2012
VFR CONDITIONS ARE EXPECTED TO PREVAIL THRU THE TAF PERIOD AT BOTH
MCK AND GLD...WITH A CHANCE OF MVFR LATE IN THE PERIOD AT MCK. FOR
THE REST OF TODAY THERE WILL BE A FEW HIGH CLOUDS AS SURFACE WINDS
TURN FROM THE EAST TO SOUTH. WIND SPEEDS WILL BE LIGHT
TODAY...INCREASING AT GLD EARLY TOMORROW MORNING AT GLD AS A SURFACE
TROUGH OVER EASTERN COLORADO STRENGTHENS AND A WARM FRONT GRADUALLY
PUSHES NORTH THROUGH THE AREA. AT MCK THERE IS THE POSSIBILITY FOR
MVFR VISIBILITIES EARLY MONDAY MORNING SIMILAR TO TODAY...WITH MOST
SHORT RANGE GUIDANCE SUPPORTING THIS IDEA. HOWEVER...DID NOT INCLUDE
MENTION IN TAF DUE TO LACK OF CONFIDENCE OF HOW FAR NORTH THE FRONT
MOVES OVERNIGHT WHICH WILL DETERMINE WHERE FOG DEVELOPS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY FROM 11 AM MST /NOON CST/ TO 5 PM MST /6 PM CST/
SATURDAY FOR KSZ003-004-013>016-027>029-041-042.
CO...WIND ADVISORY FROM 11 AM TO 5 PM MST SATURDAY FOR COZ091-092.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...RRH
AVIATION...JJM/DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
224 PM MST FRI NOV 9 2012
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 224 PM MST FRI NOV 9 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW BROAD RIDGE ACROSS THE
EASTERN US CENTERED OVER THE OHIO RIVER VALLEY. UPSTREAM A TROUGH
EXTENDS SOUTH ACROSS THE WESTERN US WITH A CLOSED CENTER OVER
WASHINGTON STATE. SW FLOW IS IN PLACE OVER THE CWA BETWEEN THESE
FEATURES. AT THE SURFACE A STATIONARY FRONT CURRENTLY EXTENDS
ACROSS EASTERN COLORADO TO SOUTHWEST KANSAS.
A WARM FRONT WILL LIFT ACROSS THE CWA TONIGHT WITH BREEZY SW WINDS
AND WARMER H85 TEMPS RESULTING IN OVERNIGHT LOWS IN 40S FOR MOST
LOCATIONS. THE TROUGH OVER THE WESTERN US WILL BEGIN TO SHIFT EAST
ACROSS THE INTER-MOUNTAIN WEST THROUGH SUNDAY WITH AN ASSOCIATED
COLD FRONT MOVING SOUTHEAST TOWARDS THE CWA SATURDAY AFTERNOON.
AHEAD OF THIS FRONT SURFACE PRESSURE GRADIENT WILL BE INCREASING
FROM THE S-SW WITH H85 JET BETWEEN 40-45KT. CONFIDENCE IS HIGHEST
THAT WIND ADVISORY CRITERIA WILL BE MET ACROSS THE SOUTHEAST
CWA...THOUGH IF H7 WINDS WERE ABLE TO MIX DOWN WE COULD APPROACH
WARNING CRITERIA. IM NOT SURE WE WILL SEE 3HR OF SUSTAINED
CRITERIA IN SHERMAN COUNTY AND CHEYENNE/KIT CARSON COLORADO
COUNTIES. HOWEVER...WE SHOULD SEE GUSTS AROUND 45 MPH THERE SO I
WAS COMFORTABLE INCLUDING THEM IN THE ADVISORY.
AHEAD OF THE COLD FRONT A DRY LINE WILL SET UP ACROSS CENTRAL
KANSAS WITH THUNDERSTORMS DEVELOPING AHEAD OF THIS FEATURE. ALL
CURRENT GUIDANCE IS SHOWING THE DRY LINE REMAINING EAST OF THE
CWA...SO I DELAYED ONSET OF PRECIP IN THE EAST UNTIL FROPA AND
LEFT THUNDER OUT OF FORECAST. BEST CHANCE FOR PRECIP SHOULD BE
ACROSS THE NORTHWEST ALONG AND BEHIND THE COLD FRONT WHERE BEST
LARGE SCALE ASCENT AND GOOD MOISTURE ADVECTION WILL SPREAD INTO
CWA BY 00Z.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 1148 PM MST THU NOV 8 2012
LOW AMPLITUDE SHORTWAVE RIDGE WILL CROSS THE PLAINS DURING THE
PERIOD MONDAY THROUGH WEDNESDAY. DRY CONDITIONS AND BELOW NORMAL
TEMPERATURES ARE EXPECTED. NEXT SYSTEM WILL BE ORGANIZING IN THE
DESERT SOUTHWEST AND MAKES ITS WAY INTO THE SOUTHERN AND CENTRAL
PLAINS LATE IN THE WEEK. THERE ARE STILL SIGNIFICANT MODEL
DIFFERENCES WITH TIMING AND STRENGTH OF THE SYSTEM...BUT APPEARS
IT WILL BRING A DECENT CHANCE OF PRECIPITATION. COLD AIR WILL BE
LACKING...SO THINK IT WILL BE MAINLY RAIN WITH PERHAPS SOME LIGHT
SNOW ON THE BACKSIDE AS IT DEPARTS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1050 AM MST FRI NOV 9 2012
VFR CONDITIONS ARE EXPECTED TO PREVAIL THRU THE TAF PERIOD AT BOTH
MCK AND GLD...WITH A CHANCE OF MVFR LATE IN THE PERIOD AT MCK. FOR
THE REST OF TODAY THERE WILL BE A FEW HIGH CLOUDS AS SURFACE WINDS
TURN FROM THE EAST TO SOUTH. WIND SPEEDS WILL BE LIGHT
TODAY...INCREASING AT GLD EARLY TOMORROW MORNING AT GLD AS A SURFACE
TROUGH OVER EASTERN COLORADO STRENGTHENS AND A WARM FRONT GRADUALLY
PUSHES NORTH THROUGH THE AREA. AT MCK THERE IS THE POSSIBILITY FOR
MVFR VISIBILITIES EARLY MONDAY MORNING SIMILAR TO TODAY...WITH MOST
SHORT RANGE GUIDANCE SUPPORTING THIS IDEA. HOWEVER...DID NOT INCLUDE
MENTION IN TAF DUE TO LACK OF CONFIDENCE OF HOW FAR NORTH THE FRONT
MOVES OVERNIGHT WHICH WILL DETERMINE WHERE FOG DEVELOPS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY FROM 11 AM MST /NOON CST/ TO 5 PM MST /6 PM CST/
SATURDAY FOR KSZ003-004-013>016-027>029-041-042.
CO...WIND ADVISORY FROM 11 AM TO 5 PM MST SATURDAY FOR COZ091-092.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...JJM/DR
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1126 AM CST FRI NOV 9 2012
.AVIATION...18Z TAF. MAIN FORECAST CONCERN LIES WITH THE
CONTINUING CLOUD COVER THIS AFTERNOON...AND INCREASING WINDS
TOWARD THE END OF THE TAF PERIOD AHEAD OF AN APPROACHING COLD
FRONT. BATCH OF LOW LEVEL STRATUS CONTINUES TO AFFECT THE
TERMINAL AREA...AND EVEN WITH SATELLITE IMAGERY SHOWING THE
ERN/WRN EDGES STARTING TO ERODE...LOWERED CIG HEIGHTS SHOULD
REMAIN FOR AT LEAST ANOTHER COUPLE OF HRS. ONCE THE STRATUS DOES
ERODE...NOT EXPECTED CLOUD COVER TO CAUSE ANY OTHER ISSUES THROUGH
THE TAF PERIOD. AM A LITTLE CONCERNED ABOUT THE POTENTIAL FOR SOME
FOG LATER TONIGHT...MAINLY IN THE AREAS SEEING STRATUS TODAY AND
WHERE WINDS WILL BE LIGHTER FOR A PERIOD AS A WARM FRONT BOUNDARY
PUSHES NORTH...AND DECIDED TO INSERT A MVFR VISIBILITY MENTION.
AFTER SUNRISE...SOUTHERLY WINDS WILL BE ON THE INCREASE THROUGH
THE END OF THE TAF PERIOD...LOOKING TO ALREADY BE GUSTING NEAR 30
MPH BY 18Z.
&&
PREV DISCUSSION... /ISSUED 445 AM CST FRI NOV 9 2012/
SHORT TERM...THROUGH 12Z MONDAY. OVERNIGHT UPPER AIR ANALYSIS
INDICATES LONG WAVE TROUGHING OVER THE WESTERN AND EASTERN
CONUS...AND A RIDGE PREVAILING OVER THE CENTRAL CONUS. A CLOSED
MID LEVEL LOW IS ALSO NOTED OVER THE NORTHWESTERN CONUS...WITH
ANOTHER CLOSED MID LEVEL CIRCULATION OVER THE NORTHEASTERN CONUS.
MID AND UPPER LEVEL JET ENERGY EXTENDS FROM CALIFORNIA...NORTHEAST
INTO THE NORTHERN PLAINS AND SOUTH CENTRAL CANADA...AND THEN
SOUTHEAST ACROSS THE OHIO VALLEY AND ON INTO THE SOUTHEASTERN
CONUS. TROPOSPHERIC FLOW IS NOT OVERLY STRONG NEAR OUR AREA AS A
RESULT...MAXING OUT AT AROUND 50KTS AT VARIOUS POINTS BETWEEN
500MB AND 200MB PER 00Z SOUNDING DATA FROM KLBF. WATER VAPOR
IMAGERY CLEARLY SHOWS THE CLOSED MID LEVEL LOWS OVER THE
NORTHWESTERN AND NORTHEASTERN CONUS. INCREASING VALUES OF MID
LEVEL MOISTURE ARE ALSO NOTED ON WATER VAPOR IMAGERY ADVECTING
NORTHEAST ALONG THE FRONT OF THE LONG WAVE TROUGH...INTO THE ROCKY
MOUNTAIN RANGE AND PLAINS. SOME OF THIS MID LEVEL MOISTURE IS
PROMOTING INCREASING MID TO HIGH LEVEL CLOUD COVER OVER PORTIONS
OF THE CENTRAL PLAINS. AT THE SURFACE A STATIONARY BOUNDARY IS
NOTED EXTENDING FROM WESTERN IOWA...SOUTHWEST INTO NORTHEASTERN
KANSAS AND ON INTO SOUTHEASTERN COLORADO. THE LOW LEVEL WIND FIELD
ACROSS OUR AREA REMAINS FROM THE NORTH AS A RESULT...BUT IS FAIRLY
LIGHT AT AROUND 5KTS. IN ADDITION TO THE AFOREMENTIONED MID TO
HIGH LEVEL CLOUDS BEGINNING TO WORK INTO THE REGION...SATELLITE
IMAGERY ALSO INDICATES A STRATUS DECK OVER MUCH OF THE NORTHERN
PLAINS...WITH THIS DECK MOVING SOUTH/SOUTHEAST AT AROUND 20KTS AND
ALREADY INFILTRATING PORTIONS OF CENTRAL NEBRASKA.
GUIDANCE FROM THE NAM...RAP...AND OPERATIONAL GFS ALL SUGGEST
ISENTROPIC UPGLIDE AND SATURATION...PRIMARILY ALONG THE 290-295K
SURFACES...WILL CONTINUE TO PROMOTE STRATUS OVER PORTIONS OF THE
REGION THROUGH MIDDAY. THERE IS SOME UNCERTAINTY AS TO HOW FAR
SOUTH THIS STRATUS DECK WILL MOVE ACROSS OUR CWA. THE OPERATIONAL
GFS REMAINS THE MOST AGGRESSIVE IN BRINGING THE DECK ACROSS OUR
ENTIRE CWA...WHILE THE NAM AND RAP BOTH SUGGEST THE NORTHERN HALF
OF OUR CWA WILL BE THE ONLY LOCATIONS TO OBSERVE THIS STRATUS.
SATELLITE IMAGERY INDICATES THE STRATUS DECK HAS SLOWED THROUGH
THE PAST 2-3 HOURS AND IT NOW SEEMS UNLIKELY THIS STRATUS WILL
MAKE IT TO OUR KANSAS COUNTIES BY 12Z...WHICH IS WHAT THE
OPERATIONAL GFS SUGGESTS. GIVEN THIS...OPTED TO PLAY CLOSER TO NAM
AND RAP GUIDANCE BY KEEPING THE FORECAST STRATUS PRIMARILY OVER
THE NORTHERN HALF OF THE CWA. GUIDANCE FROM THE NAM AND RAP ALSO
SUGGEST THE LOW LEVEL BAROCLINIC ZONE TO OUR SOUTH/SOUTHEAST WILL
LIFT NORTH AS A WARM FRONT TODAY...THUS CARRYING THE PRIMARY AXIS
OF ISENTROPIC UPGLIDE FARTHER NORTH WHICH SHOULD HELP CLEAR THE
STRATUS FROM MUCH OF OUR CWA BY MIDDAY. ALTHOUGH THE INCREASING
MID AND HIGH LEVEL CLOUDS MAY KEEP TEMPERATURES FROM MEETING THEIR
FULL DIURNAL POTENTIAL TODAY...THERE SHOULD BE ENOUGH DIABATIC
HEATING FOR 20-25 DEGREE TEMPERATURE RISES WHICH SHOULD PRESENT
AFTERNOON HIGHS GENERALLY IN THE 60S AND 70S...WITH THE ONLY
EXCEPTION BEING ACROSS OUR FAR NORTH WHERE THE STRATUS MAY KEEP
TEMPERATURES IN THE 50S.
THE BIG WEATHER STORY CONTINUES TO REVOLVE AROUND THE INCOMING
SYSTEM FOR THIS WEEKEND. GUIDANCE CONTINUES TO SUGGEST THE MID
LEVEL LOW...CURRENTLY OVER THE NORTHWESTERN CONUS...WILL OPEN UP
INTO A WAVE AND MOVE EAST INTO THE CENTRAL CONUS TONIGHT THROUGH
SUNDAY. AS THE MID LEVEL TROUGH APPROACHES FROM THE
WEST...RESULTANT SURFACE CYCLOGENESIS IS EXPECTED TO COMMENCE OVER
THE HIGH PLAINS OF NORTHEASTERN COLORADO OVERNIGHT TONIGHT. THIS
SURFACE LOW IS THEN EXPECTED TO QUICKLY EJECT NORTHEAST ACROSS THE
CENTRAL PLAINS AS THE MID LEVEL TROUGH AXIS APPROACHES OUR AREA
FROM THE WEST. AS THE SURFACE LOW MOVE NORTHEAST...AN ASSOCIATED
COLD FRONT IS EXPECTED TO SWEEP ACROSS OUR AREA SATURDAY AFTERNOON
INTO SATURDAY NIGHT.
QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST MID LEVEL THERMAL ADVECTION AHEAD OF THE MID LEVEL TROUGH
AXIS...WORKING IN CONCERT WITH LOW LEVEL CONVERGENCE ALONG THE LOW
LEVEL BAROCLINIC ZONE...WILL PROVIDE SUFFICIENT LIFT FOR
CONVECTIVE INITIATION NEAR THE BAROCLINIC ZONE SATURDAY AFTERNOON.
AT THIS TIME IT APPEARS THIS CONVECTION WILL INITIALIZE IN THE
VICINITY OF A LINE EXTENDING FROM FULLERTON...TO GRAND ISLAND...TO
PHILLIPSBURG. INCREASED VALUES OF LOW LEVEL MOISTURE AHEAD OF THE
LOW LEVEL BAROCLINIC ZONE...ALONG WITH INCREASING MID LEVEL LAPSE
RATES WITH THE APPROACH OF THE MID LEVEL TROUGH AXIS...SHOULD BE
SUFFICIENT ENOUGH TO PROVIDE 0-1MLCAPE VALUES ON THE ORDER OF
1000J/KG PER THE NAM AND OPERATIONAL GFS. IN ADDITION TO THE
POTENTIAL INSTABILITY...INCREASING MID AND UPPER LEVEL JET ENERGY
WILL ALSO LIKELY PROVIDE DEEP LAYER BULK SHEAR VALUES IN EXCESS
50KTS ACROSS MUCH OF THE REGION. ALSO...FORECAST PROXIMITY
SOUNDINGS FROM ACROSS THE CWA...PER THE NAM...SUGGEST A VEERING
LOW LEVEL WIND PROFILE FOR LOCATIONS STILL AHEAD OF THE LOW LEVEL
BAROCLINIC ZONE...WITH THE NAM ALSO SUGGESTING 0-1KM SRH WILL
APPROACH 300M^2/S^2 ACROSS EAST/SOUTHEASTERN PORTIONS OF OUR CWA.
NOW...INCREASING MID AND HIGH LEVEL CLOUDS WILL LIKELY KEEP
DIABATIC HEATING DOWN A TOUCH THROUGH MUCH OF THE DAY WHICH WILL
HELP SUSTAIN SOMETHING OF A CAPPING INVERSION...WHICH MEANS
INITIAL CONVECTIVE DEVELOPMENT COULD BE IN THE FORM OF A FEW
DISCRETE CELLS IN THE VICINITY OF THE LOW LEVEL BAROCLINIC ZONE.
GIVEN THE VERY STRONG DEEP LAYER BULK SHEAR...SUPER CELL
DEVELOPMENT WILL BE MORE THAN POSSIBLE AND GIVEN THIS...WILL
CONTINUE OUTLOOKING LARGE HAIL IN THE HWO. ADDITIONAL CONVECTIVE
DEVELOPMENT ALONG THE BAROCLINIC ZONE COULD THEN POTENTIALLY
EVOLVE INTO A QLCS WITH STRONG OUTFLOW WINDS AT THE SURFACE
REMAINING VERY POSSIBLE. WILL CONTINUE TO CARRY SEVERE
THUNDERSTORM WIND WORDING IN HWO AS WELL. FINALLY...GIVEN THE LOW
LEVEL SHEAR AS INDICATED BY THE NAM...WILL ALSO GO AHEAD AND
MENTION ISOLATED TORNADIC DEVELOPMENT IN ASSOCIATION WITH THE
INITIAL CONVECTION DURING THE LATE AFTERNOON HOURS.
STRONG WINDS WILL NOT ONLY BE A THREAT WITH AFTERNOON AND EVENING
THUNDERSTORM ACTIVITY ON SATURDAY...BUT STRONG SYNOPTIC WINDS WILL
ALSO BE OBSERVED ACROSS MUCH OF THE CWA SATURDAY. AS SURFACE
CYCLOGENESIS CONTINUES ACROSS THE HIGH PLAINS SATURDAY...THE LOW
LEVEL PRESSURE GRADIENT IS EXPECTED TO INTENSIFY GREATLY HEADING
INTO SATURDAY AFTERNOON...ESPECIALLY ACROSS THE SOUTHEASTERN ONE-
HALF OF THE CWA. IN ADDITION...FORECAST PROXIMITY SOUNDINGS FROM
ACROSS OUR CWA PER THE NAM AND OPERATIONAL GFS SUGGEST BOUNDARY
LAYER MIXING TO BETWEEN 850MB AND 800MB WILL BE REALIZED...WHICH
IS WHERE ~50KT WINDS WILL BE WAITING FOR TRANSPORT TO THE SURFACE.
INTERESTING TO NOTE THAT BOTH MET AND MAV GUIDANCE SUGGEST
PORTIONS OF OUR CWA WILL HIT WIND ADVISORY CRITERIA AT SOME POINT
DURING THE DAY SATURDAY...WITH MAV GUIDANCE SUGGESTING OUR
SOUTHWEST WILL HIT BETWEEN 18Z AND 21Z...AND THE NAM SUGGESTING
OUR SOUTHEAST WILL HIT CLOSER TO 00Z. RATHER THAN BLANKET A
MAJORITY OF OUR CWA WITH WIND ADVISORY WINDS...OPTED TO KEEP WINDS
JUST UNDER WIND ADVISORY ACROSS THE SOUTHEASTERN HALF OF THE CWA
WITH THE HOPES THAT WE WILL BE ABLE TO FINE-TUNE THE WIND FORECAST
AND INCREASE WINDS SOMEWHAT...INTO WIND ADVISORY CRITERIA...FOR
PORTIONS OF THE CWA ONCE THAT FORECAST BECOMES MORE CLEAR. WILL GO
AHEAD AND CONTINUE TO CARRY STRONG SYNOPTIC WIND WORDING IN THE
HWO FOR SATURDAY AFTERNOON. STRONG SYNOPTIC WINDS WILL NOT ONLY BE
A THREAT SATURDAY AFTERNOON...BUT WILL ALSO BE POSSIBLE SATURDAY
NIGHT INTO EARLY SUNDAY MORNING AFTER THE LOW LEVEL BAROCLINIC
ZONE CLEAR THE AREA. INTENSE LOW LEVEL PRESSURE RISES POST-FROPA
WILL PROMOTE YET ANOTHER INCREASE IN THE LOW LEVEL PRESSURE
GRADIENT ACROSS THE CWA 00Z-12Z SUNDAY...WITH GUIDANCE SUGGESTING
~20KT SUSTAINED WINDS WILL BE REALIZED ACROSS MUCH OF THE AREA.
WILL GO AHEAD AND CONTINUE CARRYING STRONG SYNOPTIC WIND WORDING
IN THE HWO FOR SATURDAY NIGHT/SUNDAY MORNING AS A RESULT.
WITH THE INFILTRATION OF A MUCH COLDER LOW LEVEL
AIRMASS...FORECAST PROXIMITY SOUNDINGS FROM THE ACROSS THE CWA PER
THE NAM...OPERATIONAL GFS AND EC ALL SUGGEST THE LOWER TROPOSPHERE
WILL BECOME SUPPORTIVE FOR SNOW ACROSS MUCH OF THE CWA SATURDAY
NIGHT INTO SUNDAY MORNING. AT THIS TIME IT APPEARS ANY
PRECIPITATION BEHIND THE LOW LEVEL BAROCLINIC WILL REMAIN FAIRLY
LIGHT ACROSS OUR CWA...THUS ANY SNOWFALL ACCUMULATIONS ACROSS OUR
CWA SHOULD REMAIN UNDER AN INCH. LOCATIONS WEST OF HIGHWAY 281 AND
NORTH OF I-80...WHICH IS WHERE THE LOW LEVEL COLD AIR ADVECTION
WILL BE FIRST TO INFILTRATE...SEEM MOST LIKELY TO OBSERVE THE MOST
SNOWFALL ACCUMULATION. IT IS WORTH NOTING THAT A FEW FORECAST
PROXIMITY SOUNDINGS SUGGEST A BRIEF PERIOD OF SLEET NEAR THE TRI-
CITIES AREA AS THE TRANSITION FROM RAIN TO SNOW BEGINS...BUT GIVEN
THE UNCERTAINTY AND BREVITY OF ANY SUCH POTENTIAL ACTIVITY...OPTED
TO HOLD OFF FROM MENTIONING THIS IN THE FORECAST FOR THE TIME
BEING.
FINALLY...TEMPERATURES LOOK TO FALL OFF DRAMATICALLY POST-FROPA
HEADING INTO SATURDAY NIGHT...AND WITH CONTINUED LOW LEVEL COLD
AIR ADVECTION AND LINGERING CLOUD COVER DURING THE DAY
SUNDAY...ITS DOUBTFUL TEMPERATURES WILL GO MUCH OF ANYWHERE DURING
THE DAY SUNDAY. LOWS IN THE MID 20S TO MID 30S ARE CURRENTLY
FORECAST FOR SATURDAY NIGHT...WITH TEMPERATURES STRUGGLING THROUGH
THE 30S DURING THE DAY SUNDAY. THE PASSAGE OF THE SURFACE RIDGE
AND THE INTRODUCTION OF LOW LEVEL RETURN FLOW SHOULD THEN PRESENT
A WARMING TREND TO FINISH OUT THE SHORT TERM FORECAST PERIOD.
FIRE WEATHER...A LOW LEVEL BAROCLINIC ZONE IS EXPECTED TO CLEAR
WESTERN PORTIONS OF OUR CWA BY LATE MORNING OR MIDDAY SATURDAY.
ALTHOUGH LOW LEVEL COLD AIR ADVECTION WILL BEGIN PUSHING INTO THE
AREA SHORTLY AFTER FROPA...THERE WILL BE A BRIEF PERIOD IN WHICH
LOW LEVEL DRY AIR ADVECTION WILL OUTWEIGH THE COLD AIR
ADVECTION...THUS ALLOWING LOW LEVEL RELATIVE HUMIDITY TO PLUMMET
AS WE HEAD INTO THE AFTERNOON HOURS SATURDAY. AT THIS TIME IT
APPEARS LOCATIONS GENERALLY WEST OF HIGHWAY 281 AND SOUTH OF I-80
WILL OBSERVE THE LOWEST RELATIVE HUMIDITY VALUES...SOMEWHERE NEAR
25%. THESE LOW VALUES OF RELATIVE HUMIDITY...WORKING IN CONCERT
WITH A STRONG LOW LEVEL WIND FIELD...SUSTAINED WELL ABOVE 17KTS
AND GUSTS WELL ABOVE 22KTS...WILL PROVIDE AN ELEVATED FIRE WEATHER
DANGER SATURDAY AFTERNOON. AS A RESULT...WILL GO AHEAD AND PRESENT
ELEVATED FIRE WEATHER WORDING IN THE FWF AND HWO.
LONG TERM...MONDAY THROUGH THURSDAY
THE MAIN THEME: ANOMALOUS "MID-WINTER"LIKE COLD EASES WITH TEMPS
REBOUNDING TO NORMAL AS FAVORABLE PATTERN DELIVERS ANOTHER PCPN
EVENT NEXT THU NGT-FRI AND MORE IN THE OFFING AFTER THAT.
HAZARDS: NONE FORESEEN ATTM. HOWEVER OUR CURRENT MIN RH IS FCST
AROUND 25% NEXT WED. IF WINDS END UP BREEZIER THAN CURRENTLY
EXPECTED...CAN SEE THIS BEING A DAY OF ELEVATED FIRE DANGER.
BIG PICTURE: BELIEVE OVERALL PATTERN CONTINUES TO SUGGEST MORE
RAIN IN OUR FUTURE...ESPECIALLY ALONG AND E OF HWY 281. THE NAO
WILL TRANSITION TO ITS POSITIVE PHASE NEXT WEEK WITH THE PNA
REMAINING NEGATIVE. THIS PHASE CONFIGURATION WILL BE SUPPORTIVE OF
AN ERN USA RIDGE/WRN USA TROF THRU MID-MONTH AND DELIVERS AT LEAST
TWO MORE FORESEEABLE CHANCES FOR PCPN. OVERALL...TEMPS WILL
AVERAGE NEAR NORMAL THRU NEXT THU.
QPF: THE NEXT DECENT OPPORTUNITY CONTS TO BE OUTLOOKED FOR NEXT
THU NGT-FRI /15TH-16TH/. MODELS ARE STRUGGLING WITH RUN-TO-RUN
CONSISTENCY ON HOW POTENT TO KEEP THE UPPER-LEVEL SYSTEM. THE 00Z
EC ENSEMBLE MEAN SHOWS SOME SPREAD AT THE BASE OF THE TROF. THIS
HAS IMPLICATIONS FOR PCPN AMTS. IF THE UPPER SYSTEM REMAINS
OPEN...IT WILL MOVE THRU FASTER WITH LESS OF AN OPPORTUNITY FOR
PCPN. WE`RE HOPING IT REMAINS CLOSED AS WE STRUGGLE TO EVEN
MAINTAIN NORMAL PCPN AMTS. ONCE THIS SYSTEM DEPARTS...WE GET
ANOTHER QUIET INTERLUDE NEXT WEEKEND. THEN WE LOOK TO THE 19TH-
20TH FOR THE NEXT TROF AND RAIN POTENTIAL.
THE DAILY DETAILS...
MON: THE UPPER TROF/CORE OF THE COLDEST AIR DEPARTS INTO THE MS
VALLEY...ALLOWING TEMPS TO EASE UPWARD. HIGH PRES AT THE SFC.
AFTER A BONE-CHILLING START WITH MOST PLACES IN THE TEENS...A NICE
BUT STILL CHILLY DAY.
TUE: LOW AMPLITUDE SHORTWAVE RIDGE WITH STRONG HIGH PRES OVER THE
ERN USA. THIS HIGH REMAINS PARKED THERE THRU THE REST OF THE WEEK
WITH A TENDENCY TO DRIFT TOWARD NEW ENGLAND. SUNNY. TEMPS RETURN
TO NEAR NORMAL /NOW ONLY IN THE LOWER 50S/.
WED: THE TRAILING END OF A WEAK COOL FRONT MOVES THRU LATE. THIS
MAY END UP MORE OF A WINDSHIFT LINE. ALL QG FORCING/MSTR WILL BE
FAR TO THE N. DRY WITH SEASONAL/NORMAL TEMPS. MORE BREEZY AS LEE
LOW DEVELOPS OVER CO...INTENSIFYING THE GRADIENT.
THU: NW FLOW/SHORTWAVE RIDGING AS PAC TROF MOVES INTO DESERT SW.
INCREASING CLOUDS AND BREEZY.
FRI: UPPER TROF EJECTS INTO SRN/CNTRL PLAINS. RAIN LOOKING
PROBABLE AND MAY BEGIN THU NGT. GFS ENSEMBLE PCPN PROBABILITIES
ARE HIGH WITH A 70% CHANCE FOR .10 IN 24 HRS WITH POTENTIAL FOR
MORE.
COOLER WITH TEMPS PROBABLY HELD DOWN IN THE 40S.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
503 PM EST FRI NOV 9 2012
.SYNOPSIS...
A STRENGTHENING WARM FRONTAL BOUNDARY WILL EXTEND FROM THE UPPER
GREAT LAKES TO LAKE ERIE TONIGHT...THEN WILL SLOWLY LIFT TO THE
NORTH ACROSS OUR REGION DURING THE DAY SATURDAY. THIS WILL KEEP OUR
FORECAST AREA SHROUDED WITH CLOUDS WHILE EVENTUALLY PROMOTING SOME
SHOWER ACTIVITY. THE SILVER LINING TO THIS PROCESS WILL BE THE NEAR
RECORD WARMTH THAT WILL FOLLOW FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
SOME VERY ISOLATED LAKE EFFECT SHOWERS HAVE DEVELOPED EAST OF LAKE
ONTARIO IN A NARROW BAND ACROSS FAR NORTHERN OSWEGO COUNTY AT 4PM.
THERE IS JUST ENOUGH COOL AIR OVER THE EAST END OF THE LAKE FOR LAKE
INDUCED CAPE OF 100-200 J/KG. SOME ADDITIONAL WEAK LIFT IS PRESENT
WITH THE 850 MB WARM FRONT ORIENTED JUST TO THE WEST FROM TORONTO
SOUTHEAST TO ROCHESTER. UPDATED FORECAST GRIDS FOR THIS NARROW BAND
WHICH THE 19Z HRRR MODEL SHOWS WELL. ONCE THE 850MB FRONT SLIDES A
BIT FURTHER NORTH THIS EVENING THE WARM ADVECTION ALOFT WILL END
ANY LAKE INSTABILITY.
PREVIOUS DISCUSSION...
THE NEXT 24 HOURS WILL BE A TRANSITION PERIOD BETWEEN THE EXTENSIVE
STRETCH OF CHILLY WEATHER THAT WE HAVE EXPERIENCED FOR THE PAST TWO
WEEKS...AND A WELCOMED BATCH OF ANOMALOUS WARMTH THAT WILL CARRY US
INTO THE START OF THE NEW WORK WEEK. MORE ON THIS IN A MOMENT.
MID AND UPPER LEVEL RIDGING WILL BE FOUND OVER THE REGION TONIGHT
WHILE A VERY WEAK SURFACE BOUNDARY WILL SAG SOUTH FROM SOUTHERN
ONTARIO. THIS BOUNDARY WILL STALL OVER THE VCNTY OF THE PENNSYLVANIA
BORDER DURING THE WEE HOURS OF THE MORNING BEFORE LIFTING BACK TO
THE NORTH ON SATURDAY IN THE FORM OF A WARM FRONT. WHILE THERE WILL
BE VERY LITTLE LIFT ASSOCIATED WITH THE PASSAGE OF THIS BOUNDARY...
WE WILL CONTINUE TO BE SHROUDED UNDER A WEALTH OF CLOUD COVER.
SAT IMAGERY SHOWS EXTENSIVE MID LEVEL MOISTURE (ALTO-CU) STREAMING
EASTWARD ACROSS ALL OF THE GREAT LAKES REGION. THIS MOIST FLOW WILL
CONTINUE THROUGH TONIGHT...ENSURING US OF KEEPING OUR MAINLY CLOUDY
SKIES. THE CLOUD COVER WILL KEEP OUR OVERNIGHT TEMPERATURES A FEW
DEGREES HIGHER THAN THOSE OF LAST NIGHT...WITH LOWS GENERALLY
RANGING FROM THE LOWER 30S EAST OF LK ONTARIO TO THE MID AND UPPER
30S OVER THE WESTERN COUNTIES.
AS WE PROGRESS THROUGH THE PRE DAWN HOURS...THE AFOREMENTIONED
FRONTAL BOUNDARY WILL START TO LIFT BACK TO THE NORTH. THE
ASSOCIATED ISENTROPIC LIFT SHOULD BE STRONG TO HELP GENERATE SOME
SHOWERS OVER THE SOUTHWEST CORNER OF THE STATE BEFORE DAYBREAK...
WITH THE SHOWERS GRADUALLY LIFTING NORTH ACROSS WESTERN NEW YORK
BETWEEN DAYBREAK AND LUNCHTIME ON SATURDAY.
DURING THE COURSE OF SATURDAY AFTERNOON...THE WARM FRONT WILL
CONTINUE ITS NORTHEASTWARD TREK BY MOVING FROM THE FINGER LAKES TO
THE EASTERN LAKE ONTARIO REGION....WHERE ANY ASSOCIATED LIGHT
SHOWERS WILL BE FOCUSED. WILL USE CHC POPS FOR THE BULK OF THE
REGION WITH THE EXCEPTION OF THE SRN TIER WHERE LIKELY POPS WILL BE
USED EARLY IN THE MORNING.
THE CLOUDS SHOULD THIN OUT ACROSS THE SRN TIER IN THE WAKE OF THE
FRONT DURING THE MID AND LATE AFTERNOON...AND BEING IN THE WARM
SECTOR...THIS AREA SHOULD BE ABLE TO EXPERIENCE HIGH TEMPERATURES IN
THE LOW TO MID 50S. MERCURY READINGS WILL SOME 10 DEG F LOWER ACROSS
THE NORTH COUNTRY.
SPEAKING OF TEMPS...READINGS ACROSS OUR FORECAST AREA HAVE AVERAGED
OVER 5 DEG F BELOW NORMAL DURING THE PAST TWO WEEKS. THIS TREND WILL
END TODAY. AS WE PROGRESS THROUGH THE END OF THE WEEKEND INTO EARLY
NEXT WEEK...TEMPS BEHIND THE WARM FRONT WILL BE AS MUCH AS 20
DEGREES F ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
THE NORTHWARD PASSAGE OF THE WARM FRONT ON SATURDAY NIGHT WILL ALSO
LIFT AND SHIFT ANY REMAINING PRECIP TO THE NORTH AND EAST. WILL
CARRY CHANCE POPS FOR THE NORTH COUNTRY AND THE SAINT LAWRENCE RIVER
FOR THE EVENING AND EARLY NIGHT...THEN UPPER AND MID LEVEL RIDGING
WILL SUPPRESS PRECIP ACROSS THE REST OF THE REGION. OVERNIGHT TEMPS
WILL SLIP ONLY A FEW DEGREES TO EARLY LOWS IN THE 40S...THEN CLIMB
SLOWLY OVERNIGHT TO THE MID TO UPPER 40S ALONG THE LAKE PLAINS AND
LOWER TO MID 40S ELSEWHERE.
THE WARM AIR WILL COVER THE REGION ON SUNDAY WITH TEMPERATURES CLOSE
TO RECORD HIGHS. THE RECORD HIGH TEMPERATURE OF 68 DEGREES IN
BUFFALO MAY BE TIED OR BROKEN...BUT ROCHESTER`S RECORD HIGH OF 73
MAY BE TOUGHER TO REACH. SUNNY SKIES WILL PREVAIL WITH A SOUTHERLY
BREEZE.
A COLD FRONT WILL APPROACH ON MONDAY WITH A DEEP MERIDIONAL
PATTERN...THE FRONT REACHING FROM LOW PRESSURE LIFTING NORTH FROM
THE WESTERN GREAT LAKES ALL THE WAY SOUTH TO THE GULF OF MEXICO.
SOUTHERLY WINDS WILL BE ON THE INCREASE AHEAD OF THE FRONT RANGING
15 TO 25 MPH AND GUSTING OVER 30 MPH. IT APPEARS THAT WE WILL NOT
REACH WIND ADVISORY CONDITIONS ON MONDAY...BUT IT IS WORTH CONTINUED
SCRUTINY.
THE COLD FRONT AND ASSOCIATED PRECIP WILL CROSS THE REGION MONDAY
NIGHT. THERE IS THE POSSIBILITY OF THUNDER ALONG THE FRONT AS BOTH
GFS AND ECMWF ARE SHOWING 850MB SOUTHERLY JET OF 50-60KT...WILL HOLD
ON INTRODUCING THUNDER ON THIS FORECAST SET UNTIL THE PATTERN
BECOMES MORE CERTAIN.
SUNDAY NIGHT WILL COOL TO OVERNIGHT LOW TEMPS IN THE LOWER 50S TO
UPPER 40S...THEN PREFRONTAL WARMING WILL RAISE TEMPS BACK TO THE
LOWER TO MID 60S ON MONDAY. NOT AS WARM AS SUNDAY AS THE CLOUDS WILL
THICKEN AHEAD OF THE APPROACHING FRONT. LOWS MONDAY NIGHT WILL BE
OCCUR FOLLOWING THE FRONTAL PASSAGE...FALLING TO THE UPPER 30S TO
LOW 40S ACROSS THE WESTERN COUNTIES AND TO THE MID TO UPPER 40S FOR
CENTRAL AND NORTHERN NEW YORK.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE COLD FRONT WILL CONTINUE ACROSS THE REGION ON TUESDAY WITH MUCH
COLDER AIR TO FOLLOW. THE BULK OF THE RAIN WILL BE ALONG OR PAST THE
EASTERN EDGE OF THE FORECAST AREA. THE TIMING OF THE FRONTAL PASSAGE
IS SIMILAR ON GFS AND ECMWF AS ARE THE PLACEMENT AND TRACK OF THE
TRAILING UPPER TROUGH AND THE BOUNDARY LAYER THERMAL PATTERN AND
COOLING. WILL EXPECT 850MB TEMPS OF -6C TO -8C DURING MUCH OF
TUESDAY AND ABOUT 6KFT TO 8KFT DEPTH TO THE UNSTABLE BOUNDARY
LAYER...THUS SOME LAKE RESPONSE IS EXPECTED. WILL HAVE SCATTERED
LAKE EFFECT SNOW SHOWERS TO THE EAST OF THE LAKES DURING
TUESDAY...TRANSITIONING TO A GEORGIAN BAY TO LAKE ONTARIO CONNECTION
ON MORE NORTHWESTERLY FLOW DURING TUESDAY NIGHT. THE SHALLOW DEPTH
OF THE UNSTABLE LAYER AND DRY AIR ALOFT SHOULD SUBSTANTIALLY LIMIT
THE AMOUNT OF LAKE EFFECT PRECIP...BUT SHOULD SEE ENOUGH FOR A
COATING TO AN INCH OR SO ACROSS THE TOP OF THE CHAUTAUQUA RIDGE AND
THE SOUTHERN TO WESTERN SLOPES OF THE TUG HILL AND SOUTHERN OSWEGO
COUNTY.
SURFACE HIGH PRESSURE OVERLAIN BY A ZONAL FLOW ALOFT FROM WEDNESDAY
THROUGH FRIDAY WILL BRING A PERIOD OF BENIGN AND DRY WEATHER WITH A
SLOW WARMING TREND. OVERNIGHT LOW TEMPS WILL BE IN THE MID 20S TO
LOW 30S EACH NIGHT WITH HIGHS ON WEDNESDAY IN THE MID 30S TO LOW 40S
CLIMBING TO THE LOWER TO MID 40S ON THURSDAY AND THE UPPER 40S TO
LOW 50S ON FRIDAY.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
MIX OF VFR AND MVFR CIGS ARE PRESENT ACROSS THE MAJORITY OF THE
REGION THIS EVENING AS A WEAK WARM FRONT IS POSITIONED JUST SOUTH OF
THE STATE. A VERY NARROW BAND OF LAKE EFFECT RAIN IS PRESENT EAST OF
LAKE ONTARIO SOUTH OF THE KART TERMINAL.
FOR TONIGHT...THE ALTO-CU DECK WILL REMAIN IN PLACE THROUGH
MIDNIGHT WITH CIGS GRADUALLY LOWERING OVERNIGHT. CIGS MAY DROP TO
MVFR LEVELS AGAIN AT KJHW AS LIGHT SHOWERS DEVELOP LATE IN THE VCNTY
OF A WARM FRONT. THE WEAK LAKE BAND SOUTH OF KART WILL FALL APART A
LITTLE LATER THIS EVENING WHEN MID LEVEL WARM AIR SPREADS OVER THE
LAKE.
SATURDAY THE SURFACE WARM FRONT WILL LIFT NORTH ACROSS THE STATE
THROUGH THE DAY WITH RAIN SHOWERS DEVELOPING ALONG AND AHEAD. MAINLY
LOW END VFR OR MVFR CIGS EXPECTED. SOME EARLY MORNING IFR CIGS COULD
DEVELOP AT KJHW WITH ANY SHOWERS BEFORE SUNRISE..
OUTLOOK...
SATURDAY NIGHT...MAINLY VFR WITH A CHANCE OF RAIN SHOWERS EAST OF
LAKE ONTARIO.
SUNDAY...VFR.
MONDAY...VFR DURING THE DAY THEN VFR/MVFR IN RAIN WITH FRONTAL
PASSAGE MON NIGHT.
TUESDAY...MVFR IN SCTD SNOW SHOWERS.
&&
.MARINE...
A WEAK FRONTAL BOUNDARY JUST NORTH OF LAKE ONTARIO THIS EVENING WILL
GRADUALLY DROP SOUTH ACROSS WESTERN NEW YORK DURING THE OVERNIGHT.
THIS WILL ALLOW MODERATE WEST TO SOUTHWEST BREEZES EARLY TONIGHT TO
BECOME LIGHT AND VARIABLE BEFORE FRESHENING FROM THE EAST LATE
TONIGHT AND SATURDAY. WHILE WINDS AND WAVES WILL BE CLOSE TO SCA
CRITERIA FROM SODUS BAY TO MEXICO BAY THIS EVENING...CONDITIONS
THROUGH SATURDAY SHOULD NOT WARRANT ANY MARINE FLAGS.
WINDS WILL VEER TO A SOUTHERLY COMPONENT IN THE WAKE OF A WARM FRONT
DURING THE SECOND HALF OF THE WEEKEND...FIRST OVER LAKE ERIE AND
EVENTUALLY OVER LAKE ONTARIO. AS THESE WINDS INCREASE LATE SUNDAY
NIGHT AND MONDAY...SCA WILL LIKELY BE NEEDED.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RSH
NEAR TERM...RSH/SMITH
SHORT TERM...WCH
LONG TERM...WCH
AVIATION...RSH/SMITH
MARINE...RSH
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
338 PM CST FRI NOV 9 2012
.DISCUSSION.../ISSUED AT 338 PM CST/
COMPLICATED FORECAST THROUGH SATURDAY NIGHT AS A STRONG AREA OF LOW
PRESSURE PUSHES TOWARDS THE REGION. FOR TONIGHT...EXPECT ANOTHER
AREA OF STRATUS TO FORM OVER EASTERN NEBRASKA AND MOVE NORTH INTO
OUR REGION. THIS AREA WILL LIKELY KEEP LOCATIONS ALONG AND NORTH OF
INTERSTATE 90 LOCKED IN THE CLOUDS MUCH OF THE NIGHT. LOCATIONS TO
THE SOUTH MAY SEE THIS STRATUS ACTUALLY LIFT NORTH OF THEM FOR A
PERIOD TONIGHT. EITHER WAY STILL EXPECTING LOW STRATUS TO REFORM
LATE TONIGHT INTO TOMORROW MORNING OVER MUCH OF THE AREA...WITH
AREAS OF FOG ALSO LIKELY. DRIZZLE SHOULD BE CONFINED TO OUR
NORTHEAST AREAS WHERE SOME WEAK LIFT WILL COINCIDE WITH THE DEEPEST
LOW LEVEL MOISTURE. NOT EXPECTING MUCH IF ANY MEASURABLE PRECIP
TONIGHT AS FORCING REMAINS WEAK AND MOISTURE SHALLOW. LOWS WONT DROP
TOO MUCH...AS THE CLOUDS...A BREEZE AND LOW LEVEL MOISTURE ADVECTION
WILL KEEP THEM IN THE 40S TO NEAR 50.
MODELS ARE TRENDING SLOWER WITH THE SYSTEM AND COLD FRONT FOR
SATURDAY. AS THE WARM FRONT LIFTS NORTH...STRONG SOUTHWESTERLY
FLOW SHOULD BE PRETTY EFFECTIVE AT DISSIPATING THE STRATUS. THUS IT
SHOULD BE QUITE THE WARM DAY ACROSS THE SOUTHEAST HALF OF THE AREA
WITH HIGHS IN THE 60S AND LOW 70S. WINDS WILL BE STRONG ACROSS
NORTHWEST IOWA AND PORTIONS OF SOUTHWEST MINNESOTA WITH BOUNDARY
LAYER MEAN WINDS APPROACHING 30 KTS. MAY EVEN END UP CLOSE TO WIND
ADVISORY CRITERIA...BUT WILL LET FUTURE SHIFTS TAKE ANOTHER LOOK.
FRONT SHOULD ENTER OUR WEST BY AROUND NOON...APPROACH INTERSTATE 29
BY MID AFTERNOON AND EXIT THE CWA DURING THE EVENING. WINDS WILL BE
STRONG OUT OF THE NORTHWEST BEHIND THE FRONT...WITH NEAR ADVISORY
CRITERIA ALSO POSSIBLE WEST OF THE JAMES RIVER. TOTAL PRECIP FROM
THE SYSTEM SHOULD BE GENERALLY UNDER A QUARTER INCH WEST OF
INTERSTATE 29 AND A QUARTER TO ISOLATED HALF INCH AMOUNTS TO THE
EAST...HEAVILY DEPENDENT ON ANY CONVECTIVE DEVELOPMENT SATURDAY
EVENING.
OTHER THINGS OF NOTE WILL BE SEVERE WEATHER POTENTIAL AHEAD OF THE
FRONT AND SNOW BEHIND IT. SEVERE POTENTIAL LOOKS PRETTY MINIMAL
ACROSS OUR CWA. STRONG CAPPING LOOKS PREVALENT AHEAD OF THE FRONT
AND THE BEST FRONTAL CONVERGENCE SHOULD STAY SOUTH OF OUR CWA. MOST
OF THE ACTIVITY LOOKS POST FRONTAL FOR US...WITH POSSIBLY AN AREA OF
ELEVATED THUNDERSTORMS EAST OF INTERSTATE 29. WILL HAVE TO CONTINUE
TO MONITOR THOUGH...ESPECIALLY ACROSS OUR FAR SOUTHEAST COUPLE
COUNTIES. IT IS POSSIBLE THAT A FEW STORMS COULD FORM OVER EASTERN
NEBRASKA AHEAD OF THE FRONT AND MOVE NORTHEAST AND CLIP OUR AREA
SATURDAY EVENING. ANY PRE FRONTAL CONVECTION WOULD HAVE THE
POTENTIAL OF BECOMING SEVERE...WITH IMPRESSIVE WIND PROFILES NOTED
ON SOUNDINGS...MAIN THREAT WOULD BE STRONG WINDS. ANY SNOW THREAT
WILL BE AS THE MID LEVEL FRONT MOVES ACROSS...AS THE BEST DYNAMICAL
LIFT STAYS TO OUR NORTHWEST. RAIN SHOULD MIX WITH AND CHANGE TO SNOW
FROM WEST TO EAST SATURDAY NIGHT. CURRENT INDICATIONS ARE THAT MUCH
OF THE SNOW STAYS TO OUR NORTHWEST CLOSER TO THE BETTER LIFT. THUS
ONLY THINKING AROUND AN INCH OF SNOW ALONG AND WEST OF THE JAMES
RIVER...WITH UNDER AN INCH ELSEWHERE. /CHENARD
SUNDAY BY FAR THE QUIETER DAY OF THE WEEKEND...WITH UPPER WAVE
LIFTING OFF TO THE NORTHEAST AND COLD FRONT/ASSOCIATED MID LEVEL
FRONT PUSHING EAST OF THE CWA. WILL HANG ONTO SOME SMALL POPS IN THE
FAR SOUTHEAST FOR LINGERING LIGHT PRECIP WITH THE MID LEVEL FRONT...
AND SLIGHT CHANCE OF LIGHT SNOW BAND LIFTING NORTH OUT WESTERN CWA.
OTHERWISE EXPECT TO SEE DECENT CLEARING ACROSS THE SOUTH WITH SOME
POTENTIAL FOR AFTERNOON STRATOCU DEVELOPMENT IN THE NORTH AS
TRAILING WAVE SWINGS ACROSS THE EASTERN DAKOTAS. TEMPERATURES WILL
BE SHARPLY COLDER THAN SATURDAY...THOUGH WITH THE POTENTIAL FOR AT
LEAST PARTLY SUNNY SKIES AND STRONG MIXING IN POST FRONTAL AIR
MASS...THINK TEMPERATURES ACROSS THE WEST/NORTH WILL BE ABLE TO
RECOVER A FEW DEGREES FROM MORNING LOWS INTO THE MID-UPPER 20S...
WHILE SOUTHEAST AREAS REMAIN FAIRLY STEADY IN THE LOWER 30S. WILL
FEEL MORE RAW THOUGH...AS GUSTY WEST-NORTHWEST WINDS PUSH WIND CHILL
VALUES INTO THE TEENS MOST OF THE DAY. WINDS STAY UP IN CONTINUED
NORTHWEST FLOW SUNDAY NIGHT...WHICH WILL KEEP TEMPS FROM COMPLETELY
BOTTOMING OUT...THOUGH LOWS IN THE TEENS STILL LOOK REASONABLE GIVEN
COLD AIR MASS.
UPPER TROUGH EXITS OFF TO THE EAST THROUGH THE GREAT LAKES MONDAY
WITH QUASI-ZONAL FLOW THEN DOMINATING THROUGH MOST OF NEXT WEEK.
TEMPERATURES WILL REMAIN QUITE COOL ON MONDAY...THOUGH TEMPERATURE
GRADIENT WILL PIVOT TO A MORE NORTHWEST-SOUTHEAST ORIENTATION...WITH
HIGHS FROM MID-UPPER 20S IN SOUTHWEST MN TO LOWER 30S THROUGH THE
MISSOURI VALLEY. MODERATION IN TEMPERATURES WILL BEGIN TUESDAY AS
SOUTHERLY FLOW KICKS IN BEHIND THE SURFACE RIDGE. ANY SNOWFALL FROM
THIS WEEKENDS SYSTEM COULD HOLD TEMPS BACK A BIT IN THE WEST...BUT
SHOULD GENERALLY SEE HIGHS IN THE UPPER 30S TO MID 40S TUESDAY.
EXPECT WEDNESDAY TO BE WARMEST DAY OF THE WEEK...WITH HIGHS AT LEAST
IN THE MID 40S TO LOWER 50S AS 925MB TEMPS WARM BACK INTO THE 5-10C
RANGE AHEAD OF WEAK COOL FRONT WHICH PUSHES SOUTHEAST THROUGH THE
REGION WEDNESDAY NIGHT.
MODELS SHOWING A WEAK WAVE KICKING OUT INTO THE PLAINS LATE NEXT
WEEK FRIDAY/SATURDAY TIME FRAME. 09/12Z RUN OF ECMWF IS A LITTLE
FASTER WITH THIS THAN ITS 09/00Z COUNTERPART...AND THAN THE 09/12Z
GFS. WITH UNCERTAINTY IN THE TIMING AT THIS RANGE...WILL KEEP THE
FORECAST DRY FOR NOW WITH SEASONABLE HIGHS IN THE 40S FOR THURSDAY
AND FRIDAY.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
COMPLICATED AND LOW CONFIDENCE TAF FORECAST THROUGH 18Z SATURDAY.
CURRENTLY SEEING STATUS RANGING FROM LIFR TO MVFR...WHICH IS SLOWLY
ERODING FROM EAST TO WEST. RAP AND HRRR SEEMS TO BE HANDLING THIS
THE BEST...ALTHOUGH IT IS LIKELY A LITTLE TO FAST WITH THE CLEARING.
THUS EXPECT CLEARING TO REACH KFSD THIS AFTERNOON FOR A BRIEF
TIME...WITH KHON LIKELY STAYING STUCK IN THE CLOUDS. ANOTHER AREA OF
STRATUS WILL REFORM THIS AFTERNOON TO OUR SOUTH AND MOVE NORTH INTO
THIS EVENING. THUS CIGS WILL DROP BACK DOWN INTO THE IFR RANGE BY
TONIGHT...WITH AREAS OF FOG AND DRIZZLE ALSO POSSIBLE. SOME LIFR
ONCE AGAIN SEEMS LIKELY LATE TONIGHT INTO TOMORROW MORNING.
SOUTHWESTERLY WINDS AHEAD OF THE FRONT SHOULD HELP MIX OUT THE
STRATUS QUICKER TOMORROW...WITH IT BEGINNING TO LIFT FROM SOUTH TO
NORTH BY 18Z. /CHENARD
&&
.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
1108 AM CST FRI NOV 9 2012
.DISCUSSION.../ISSUED AT 1035 AM CST/
TRICKY FORECAST FOR TODAY WITH LOW STRATUS AND AREAS OF FOG
CURRENTLY HANGING TOUGH ACROSS ALL BUT THE FAR SOUTHEAST PORTION OF
THE CWA. HRRR AND RUC ARE HANDLING THE CURRENT SITUATION WELL...BUT
BOTH APPEAR TO SCOUR OUT THE STRATUS TOO QUICKLY LATE THIS
MORNING...GIVEN EASTERLY WIND COMPONENT ACTING TO SLOW EROSION.
MEANWHILE A SECOND AREA OF STRATUS WILL LIKELY FORM THIS AFTERNOON
TO OUR SOUTH AND PUSH INTO OUR AREA THIS AFTERNOON. GFS SEEMS TOO
AGGRESSIVE WITH THIS. SO WE SHOULD SEE SOME DECENT SUN TODAY IN OUR
FAR SOUTHEAST. THINKING OTHER AREAS STAY MAINLY CLOUDY...AS BY THE
TIME THE CURRENT STATUS BEGINS TO ERODE...OUR NEXT BATCH WILL BE
MOVING IN FROM THE SOUTH. TRENDED TEMPERATURES DOWN TOWARDS THE
COOLER MAV...EXCEPT ACROSS OUR SOUTHEAST WHERE DECENT SUN SHOULD
STILL ALLOW MID OR EVEN UPPER 50S BY THIS AFTERNOON. /CHENARD
.PREVIOUS DISCUSSION.../ISSUED AT 427 AM CST/
BOUNDARY HAS SETTLED SOUTH OF THE CWA OVERNIGHT...AND IN WAKE A
FAIRLY WIDESPREAD STRATUS FIELD ACROSS THE NORTHERN AND WESTERN CWA.
DEALING WITH THE STRATUS AND IMPACT ON TEMPERATURES IS THE MAIN
ISSUE FOR TODAY. DRY AIR POISED TO THE EAST WILL LIKELY ERODE
STRATUS...WHICH EVEN FOR THE CURRENT TIME HAS A DECENT NORTHEAST
WIND SHADOW OFF THE BUFFALO RIDGE. STRATUS LOOKS MOST DIFFICULT TO
SHAKE IN THE NORTHWESTERN/WESTERN AREAS FROM KHON TOWARD LOWER BRULE
LOCATIONS...AND IN THESE AREAS LOWERED HIGHS BY SEVERAL DEGREES.
CONVERSELY...AREAS IN THE FAR SOUTHEAST WILL FIND STRATUS VACANT
FROM SKIES FOR A GOOD PART OF THE DAY...ALTHOUGH A FAIR COVERAGE OF
HIGH CLOUDS WILL STREAM THROUGH SKIES TODAY. MAINTAINED WARMER
READINGS SOUTHEAST...AND EVEN NUDGED UP IN THE FAR SOUTHEAST.
HOWEVER...NOTE ON EVENING RAOB ANALYSIS AREA OF ELEVATED MOISTURE
RETURN WITH 5-10C 850 HPA DEWPOINTS FROM OK INTO KS. AREA OF LOWER
TO MID 50S DEWPOINTS WORKING NORTHWARD AT SURFACE EVEN INTO
SOUTHERN KS AT THIS TIME. AS FLOW ALOFT TURNS MORE SOUTHERLY AND
STRENGTHENS...THE MOISTURE WORKS NORTHWARD AND LOOKS TO IMPACT AREA
STARTING AFT 21Z. SHOULD SEE INCREASE IN STRATUS WITH SOUNDINGS
CAPPING OFF MOISTURE ABOVE AS ELEVATED MIXED LAYER INCREASES THROUGH
THE DAY WITH SOUTHWEST MID LEVEL FLOW.
THIS STRATUS SHOULD CONTINUE TO BECOME MORE WIDESPREAD OVERNIGHT
NORTH OF WARM FRONT LIFTING THROUGH EASTERN NEBRASKA AND IOWA.
INCREASING SHEAR ATOP THE MOIST LAYER IS A LIKELY DRIZZLE
INITIATOR...AND WILL ALSO SEE FOG POTENTIAL INCREASE THROUGH THE
NIGHT...ESPECIALLY FOR HIGHER TERRAIN AS TOP DOWN SATURATION OCCURS.
LOWS WILL REMAIN QUITE MILD WITH THE CLOUD COVER AND INCREASING
MOISTURE...NOT TOO FAR BELOW NORMAL HIGHS...MAINLY IN THE 40S.
PRESENCE OF ELEVATED MIXED LAYER WITH WEAK WAVE RIPPLING NORTHEAST
COULD BRING A COUPLE OF LEGITIMATE LIGHT SHOWERS TO THE EASTERN CWA
LATER TONIGHT...BUT DID COVER A LOW MEASURABLE POP WITH DRIZZLE
THREAT.
CHANGES AND CHALLENGES BEGIN SATURDAY AS LARGE TROUGH IN
INTERMOUNTAIN WEST PUSHES TOWARD THE ROCKIES. PRESSURE FALLS IN THE
WESTERN PLAINS AND DEVELOPING LOW PRESSURE...WILL START TO PULL OUT
INTO THE REGION ALONG WITH A VERY STRONG COLD FRONT. BOUNDARY NOW
APPEARS TO BE JUST A TOUCH SLOWER TREND TO A FEW MODELS...WHICH WILL
OPEN THE WINDOW FOR SOME SLIGHTLY WARMER HIGHS IN THE SOUTHEAST
WHICH WILL BUST INTO THE WARM SECTOR IN THE AFTERNOON. 925 HPA TEMPS
OVERALL WOULD MIX INTO THE LOWER TO MID 70S FOR MUCH OF THE AREA
EAST OF INTERSTATE 29 AND SOUTH OF INTERSTATE 90...BUT A STRONG
INVERSION WILL BE IN PLACE TO LIMIT MIXING POTENTIAL...AND ALSO WILL
HELP TO POOL DEWPOINTS INTO THE 50S. EARLY DAY WILL SEE THE
STRATUS/DRIZZLE LIFTING NORTHWARD...AS INVERTED TROUGH WANDERS
TOWARD THE FAR WESTERN CWA. HIGHS REACHED EARLY IN THE DAY...
PERHAPS AS LATE AS MIDDAY FAR WEST...BEFORE STRONG COLD AIR
ADVECTION SLAMS INTO THE AREA. ECMWF PREFERRED OVERALL WITH
EVOLUTION OF THE VERY AMPLIFIED SYSTEM...WHICH HAS ALSO BEEN QUITE
CONSISTENT WITH OVERALL STRUCTURE.
NOT FULLY SUBSCRIBING TO THE SEVERE THREAT FOR SOUTHEASTERN THIRD OF
CWA...WITH TWO MAJOR CONCERNS BEING TOO MUCH SHEAR WITH 500 HPA
WINDS CLOSE TO 80 KNOTS...AND THE VERY CAPPED LOWER LEVELS IN PRE
FRONTAL ENVIRONMENT. AGAIN WOULD LIKELY TAKE STORMS DEVELOPING
OUTSIDE THE AREA...PERHAPS SOUTHERN NEBRASKA OR NORTHERN KANSAS...TO
RACE NORTHEAST. DID INCREASE THE EVENING POPS ACROSS NORTHWEST IOWA
TO ACCOUNT FOR THIS DEVELOPMENT/ADVECTION...WITH ONLY A VERY OUTSIDE
CHANCE FOR A SEVERE WIND GUST.
THE COLD SIDE OF THE SYSTEM PRESENTING CHALLENGES OF ITS OWN. MODELS
ARE FAR FROM AGREEING ON PRECIPITATION STRUCTURE WITHIN THE SYSTEM.
AGAIN...SIDING MORE WITH THE ECMWF/CANADIAN REGIONAL AND TO LESSER
EXTENT THE GFS /WHICH IS A NOT IMPOSSIBLE OUTLIER TOO SLOW WITH
BOUNDARY DUE TO STRONGER SECONDARY ENERGY HANGING SOUTH/... WOULD
FOCUS SOME BETTER PRECIP EVEN INTO SUNDAY THROUGH THE EASTERN CWA.
RAIN WILL START TO TRANSITION TO SNOW BY EARLY EVENING WEST OF THE
JAMES...AND ESPECIALLY MAKE INROADS TOWARDS 06Z WHEN UPPER PV SURGE
STARTS TO WORK NORTHWARD ALONG THE BOUNDARY. NOT TERRIBLY UNSTABLE
ABOVE FRONTAL SURFACE...SO NOT EXPECTING MORE THAN BROAD AREA OF
PRECIPITATION...PERHAPS WEAKLY FOCUSED FOR A WHILE AROUND 03Z-09Z.
SREF INDICATING VERY LITTLE FREEZING POTENTIAL...BUT STILL CAN SEE
WHERE SATURATION AHEAD OF THE MAIN MID LEVEL BOUNDARY AS COLD AIR
RUSHES AHEAD...MAY FIND LACK OF ICE PROCESSES IN PLACE TO SUPPORT
SOME PATCHY FREEZING DRIZZLE LATER SATURDAY NIGHT OR EARLY SUNDAY
FROM NEAR I29 AND EASTWARD. LINGERING FRONTAL BAND WILL WANE RAPIDLY
SUNDAY MORNING...AND ADDITIONAL ACCUMULATIONS WILL BE GENERALLY A
HALF INCH OR LESS AND MAINLY EARLY...AND TOTAL SNOW ACCUMULATIONS AS
A RESULT WILL DROP OFF SHARPLY EAST OF A MARSHALL TO SIOUX FALLS TO
YANKTON LINE...WITH AN INCH OR TWO WEST AND A HALF INCH OR MUCH LESS
EAST.
WINDY SUNDAY AND BREEZY MONDAY...BOTH WITH MUCH COOLER THAN NORMAL
TEMPERATURES. OVERALL WEATHER WILL BE QUIET BEYOND SUNDAY MORNING...
AND ONLY REAL CHANGES TO GUIDANCE WAS TO LOWER LOWS A BIT MORE ON
TUESDAY MORNING AS WEAK RIDGE SLIDES ACROSS THE AREA...AND RETURN
FLOW NOT EXPECTED TO BE TOO EFFECTIVE IN KEEPING WARM. LARGE SCALE
DISAGREEMENT BETWEEN MODELS TOWARD LATE WEEK...SO KEPT THINGS CLOSER
TO THE CONSENSUS. /CHAPMAN
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
COMPLICATED AND LOW CONFIDENCE TAF FORECAST THROUGH 18Z SATURDAY.
CURRENTLY SEEING STATUS RANGING FROM LIFR TO MVFR...WHICH IS SLOWLY
ERODING FROM EAST TO WEST. RAP AND HRRR SEEMS TO BE HANDLING THIS
THE BEST...ALTHOUGH IT IS LIKELY A LITTLE TO FAST WITH THE CLEARING.
THUS EXPECT CLEARING TO REACH KFSD THIS AFTERNOON FOR A BRIEF
TIME...WITH KHON LIKELY STAYING STUCK IN THE CLOUDS. ANOTHER AREA OF
STRATUS WILL REFORM THIS AFTERNOON TO OUR SOUTH AND MOVE NORTH INTO
THIS EVENING. THUS CIGS WILL DROP BACK DOWN INTO THE IFR RANGE BY
TONIGHT...WITH AREAS OF FOG AND DRIZZLE ALSO POSSIBLE. SOME LIFR
ONCE AGAIN SEEMS LIKELY LATE TONIGHT INTO TOMORROW MORNING.
SOUTHWESTERLY WINDS AHEAD OF THE FRONT SHOULD HELP MIX OUT THE
STRATUS QUICKER TOMORROW...WITH IT BEGINNING TO LIFT FROM SOUTH TO
NORTH BY 18Z. /CHENARD
&&
.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
1035 AM CST FRI NOV 9 2012
.DISCUSSION.../ISSUED AT 1035 AM CST/
TRICKY FORECAST FOR TODAY WITH LOW STRATUS AND AREAS OF FOG
CURRENTLY HANGING TOUGH ACROSS ALL BUT THE FAR SOUTHEAST PORTION OF
THE CWA. HRRR AND RUC ARE HANDLING THE CURRENT SITUATION WELL...BUT
BOTH APPEAR TO SCOUR OUT THE STRATUS TOO QUICKLY LATE THIS
MORNING...GIVEN EASTERLY WIND COMPONENT ACTING TO SLOW EROSION.
MEANWHILE A SECOND AREA OF STRATUS WILL LIKELY FORM THIS AFTERNOON
TO OUR SOUTH AND PUSH INTO OUR AREA THIS AFTERNOON. GFS SEEMS TOO
AGGRESSIVE WITH THIS. SO WE SHOULD SEE SOME DECENT SUN TODAY IN OUR
FAR SOUTHEAST. THINKING OTHER AREAS STAY MAINLY CLOUDY...AS BY THE
TIME THE CURRENT STATUS BEGINS TO ERODE...OUR NEXT BATCH WILL BE
MOVING IN FROM THE SOUTH. TRENDED TEMPERATURES DOWN TOWARDS THE
COOLER MAV...EXCEPT ACROSS OUR SOUTHEAST WHERE DECENT SUN SHOULD
STILL ALLOW MID OR EVEN UPPER 50S BY THIS AFTERNOON. /CHENARD
.PREVIOUS DISCUSSION.../ISSUED AT 427 AM CST/
BOUNDARY HAS SETTLED SOUTH OF THE CWA OVERNIGHT...AND IN WAKE A
FAIRLY WIDESPREAD STRATUS FIELD ACROSS THE NORTHERN AND WESTERN CWA.
DEALING WITH THE STRATUS AND IMPACT ON TEMPERATURES IS THE MAIN
ISSUE FOR TODAY. DRY AIR POISED TO THE EAST WILL LIKELY ERODE
STRATUS...WHICH EVEN FOR THE CURRENT TIME HAS A DECENT NORTHEAST
WIND SHADOW OFF THE BUFFALO RIDGE. STRATUS LOOKS MOST DIFFICULT TO
SHAKE IN THE NORTHWESTERN/WESTERN AREAS FROM KHON TOWARD LOWER BRULE
LOCATIONS...AND IN THESE AREAS LOWERED HIGHS BY SEVERAL DEGREES.
CONVERSELY...AREAS IN THE FAR SOUTHEAST WILL FIND STRATUS VACANT
FROM SKIES FOR A GOOD PART OF THE DAY...ALTHOUGH A FAIR COVERAGE OF
HIGH CLOUDS WILL STREAM THROUGH SKIES TODAY. MAINTAINED WARMER
READINGS SOUTHEAST...AND EVEN NUDGED UP IN THE FAR SOUTHEAST.
HOWEVER...NOTE ON EVENING RAOB ANALYSIS AREA OF ELEVATED MOISTURE
RETURN WITH 5-10C 850 HPA DEWPOINTS FROM OK INTO KS. AREA OF LOWER
TO MID 50S DEWPOINTS WORKING NORTHWARD AT SURFACE EVEN INTO
SOUTHERN KS AT THIS TIME. AS FLOW ALOFT TURNS MORE SOUTHERLY AND
STRENGTHENS...THE MOISTURE WORKS NORTHWARD AND LOOKS TO IMPACT AREA
STARTING AFT 21Z. SHOULD SEE INCREASE IN STRATUS WITH SOUNDINGS
CAPPING OFF MOISTURE ABOVE AS ELEVATED MIXED LAYER INCREASES THROUGH
THE DAY WITH SOUTHWEST MID LEVEL FLOW.
THIS STRATUS SHOULD CONTINUE TO BECOME MORE WIDESPREAD OVERNIGHT
NORTH OF WARM FRONT LIFTING THROUGH EASTERN NEBRASKA AND IOWA.
INCREASING SHEAR ATOP THE MOIST LAYER IS A LIKELY DRIZZLE
INITIATOR...AND WILL ALSO SEE FOG POTENTIAL INCREASE THROUGH THE
NIGHT...ESPECIALLY FOR HIGHER TERRAIN AS TOP DOWN SATURATION OCCURS.
LOWS WILL REMAIN QUITE MILD WITH THE CLOUD COVER AND INCREASING
MOISTURE...NOT TOO FAR BELOW NORMAL HIGHS...MAINLY IN THE 40S.
PRESENCE OF ELEVATED MIXED LAYER WITH WEAK WAVE RIPPLING NORTHEAST
COULD BRING A COUPLE OF LEGITIMATE LIGHT SHOWERS TO THE EASTERN CWA
LATER TONIGHT...BUT DID COVER A LOW MEASURABLE POP WITH DRIZZLE
THREAT.
CHANGES AND CHALLENGES BEGIN SATURDAY AS LARGE TROUGH IN
INTERMOUNTAIN WEST PUSHES TOWARD THE ROCKIES. PRESSURE FALLS IN THE
WESTERN PLAINS AND DEVELOPING LOW PRESSURE...WILL START TO PULL OUT
INTO THE REGION ALONG WITH A VERY STRONG COLD FRONT. BOUNDARY NOW
APPEARS TO BE JUST A TOUCH SLOWER TREND TO A FEW MODELS...WHICH WILL
OPEN THE WINDOW FOR SOME SLIGHTLY WARMER HIGHS IN THE SOUTHEAST
WHICH WILL BUST INTO THE WARM SECTOR IN THE AFTERNOON. 925 HPA TEMPS
OVERALL WOULD MIX INTO THE LOWER TO MID 70S FOR MUCH OF THE AREA
EAST OF INTERSTATE 29 AND SOUTH OF INTERSTATE 90...BUT A STRONG
INVERSION WILL BE IN PLACE TO LIMIT MIXING POTENTIAL...AND ALSO WILL
HELP TO POOL DEWPOINTS INTO THE 50S. EARLY DAY WILL SEE THE
STRATUS/DRIZZLE LIFTING NORTHWARD...AS INVERTED TROUGH WANDERS
TOWARD THE FAR WESTERN CWA. HIGHS REACHED EARLY IN THE DAY...
PERHAPS AS LATE AS MIDDAY FAR WEST...BEFORE STRONG COLD AIR
ADVECTION SLAMS INTO THE AREA. ECMWF PREFERRED OVERALL WITH
EVOLUTION OF THE VERY AMPLIFIED SYSTEM...WHICH HAS ALSO BEEN QUITE
CONSISTENT WITH OVERALL STRUCTURE.
NOT FULLY SUBSCRIBING TO THE SEVERE THREAT FOR SOUTHEASTERN THIRD OF
CWA...WITH TWO MAJOR CONCERNS BEING TOO MUCH SHEAR WITH 500 HPA
WINDS CLOSE TO 80 KNOTS...AND THE VERY CAPPED LOWER LEVELS IN PRE
FRONTAL ENVIRONMENT. AGAIN WOULD LIKELY TAKE STORMS DEVELOPING
OUTSIDE THE AREA...PERHAPS SOUTHERN NEBRASKA OR NORTHERN KANSAS...TO
RACE NORTHEAST. DID INCREASE THE EVENING POPS ACROSS NORTHWEST IOWA
TO ACCOUNT FOR THIS DEVELOPMENT/ADVECTION...WITH ONLY A VERY OUTSIDE
CHANCE FOR A SEVERE WIND GUST.
THE COLD SIDE OF THE SYSTEM PRESENTING CHALLENGES OF ITS OWN. MODELS
ARE FAR FROM AGREEING ON PRECIPITATION STRUCTURE WITHIN THE SYSTEM.
AGAIN...SIDING MORE WITH THE ECMWF/CANADIAN REGIONAL AND TO LESSER
EXTENT THE GFS /WHICH IS A NOT IMPOSSIBLE OUTLIER TOO SLOW WITH
BOUNDARY DUE TO STRONGER SECONDARY ENERGY HANGING SOUTH/... WOULD
FOCUS SOME BETTER PRECIP EVEN INTO SUNDAY THROUGH THE EASTERN CWA.
RAIN WILL START TO TRANSITION TO SNOW BY EARLY EVENING WEST OF THE
JAMES...AND ESPECIALLY MAKE INROADS TOWARDS 06Z WHEN UPPER PV SURGE
STARTS TO WORK NORTHWARD ALONG THE BOUNDARY. NOT TERRIBLY UNSTABLE
ABOVE FRONTAL SURFACE...SO NOT EXPECTING MORE THAN BROAD AREA OF
PRECIPITATION...PERHAPS WEAKLY FOCUSED FOR A WHILE AROUND 03Z-09Z.
SREF INDICATING VERY LITTLE FREEZING POTENTIAL...BUT STILL CAN SEE
WHERE SATURATION AHEAD OF THE MAIN MID LEVEL BOUNDARY AS COLD AIR
RUSHES AHEAD...MAY FIND LACK OF ICE PROCESSES IN PLACE TO SUPPORT
SOME PATCHY FREEZING DRIZZLE LATER SATURDAY NIGHT OR EARLY SUNDAY
FROM NEAR I29 AND EASTWARD. LINGERING FRONTAL BAND WILL WANE RAPIDLY
SUNDAY MORNING...AND ADDITIONAL ACCUMULATIONS WILL BE GENERALLY A
HALF INCH OR LESS AND MAINLY EARLY...AND TOTAL SNOW ACCUMULATIONS AS
A RESULT WILL DROP OFF SHARPLY EAST OF A MARSHALL TO SIOUX FALLS TO
YANKTON LINE...WITH AN INCH OR TWO WEST AND A HALF INCH OR MUCH LESS
EAST.
WINDY SUNDAY AND BREEZY MONDAY...BOTH WITH MUCH COOLER THAN NORMAL
TEMPERATURES. OVERALL WEATHER WILL BE QUIET BEYOND SUNDAY MORNING...
AND ONLY REAL CHANGES TO GUIDANCE WAS TO LOWER LOWS A BIT MORE ON
TUESDAY MORNING AS WEAK RIDGE SLIDES ACROSS THE AREA...AND RETURN
FLOW NOT EXPECTED TO BE TOO EFFECTIVE IN KEEPING WARM. LARGE SCALE
DISAGREEMENT BETWEEN MODELS TOWARD LATE WEEK...SO KEPT THINGS CLOSER
TO THE CONSENSUS. /CHAPMAN
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
IFR CEILINGS WILL BE IN PLACE OVER MOST OF THE AREA THROUGH MID TO
LATE MORNING. A SLIGHTLY DRIER FLOW OF AIR FROM THE EAST WILL AID IN
BREAKING UP SOME OF THIS STRATUS DURING THE AFTERNOON. CEILINGS WILL
LIKELY CLIMB BACK INTO THE MVFR CATEGORY BY LATE THIS MORNING AND
POSSIBLY INTO LOW END VFR. AREAS EAST OF INTERSTATE 29 COULD SEE
SCATTERED CLOUD COVER FOR A TIME TODAY. BUT LOWER CEILINGS WILL
AGAIN BE LIKELY OVERNIGHT AS WELL AS THE THREAT FOR SOME FOG AND
DRIZZLE...ESPECIALLY ALONG AND EAST OF INTERSTATE 29. CEILINGS AND
VISIBILITIES WILL LIKELY DROP INTO THE IFR CATEGORY. /08
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1127 AM PST Fri Nov 9 2012
.SYNOPSIS...
A slow moving low pressure area will continue to meander slowly
over the northeast corner of Washington which will result in more
light snow for the northern Idaho Panhandle and much of northeast
and north central Washington. The low will weaken overnight and be
replaced by weak ridging for the weekend. This will result in a
gradual drying trend...but cold temperatures will continue. Wet
and snowy weather is expected to return to the region by the
beginning of the next work week.
&&
.DISCUSSION...
Morning Update: Steady light snow with embedded heavier showers
continue along the northeastern periphery of a 700mb low. HRRR is
handling the current situation well and was generally referenced
for the remainder of the afternoon. Consequently, the main axis of
light snow will stretch from Lookout Pass...northwest to Sherman
Pass and this is where we will continue the snow advisory for now
with the main travel impacts being along roads that climb near
3000 feet or higher. This does not mean the valleys will escape
with no impacts but snow accumulations on roads will be confined
to isolated heavier showers. Meanwhile, drier, continental air
moving down the Purcell Trench continues to work against the snow
processes aloft and has resulted in little to no snow from
Sandpoint northward. All things considered, we have trimmed
several areas from the snow advisory including the Bonners Ferry
area, Spokane-CDA, and valleys west of Colville. Given the persistent
and heavier shower activity from Deer Park Chewelah, we left this
section of Hwy 395 in the advisory. See the "Detailed Hazard" tab.
South of the main low, sunbreaks have lead to increasing
instability and light showers will be possible just about
anywhere. We are not real concerned with snow accumulations with
this activity given the warmer surface temperatures. We will have
to keep a close eye on activity for the Blue Mtns and Camas
Prairie where orographic flow is a bit more northwesterly. /sb
&&
.AVIATION...
18Z TAFS: Steady snow and snow showers will continue along and
north of a line from COE-GEG. We do not expect additional
accumulations away from grassy surfaces. IFR cigs will trend MVFR
as drier air works in from the northeast. This will lead to breezy
winds down the Purcell Trench from COE-SZT with gusts to 30 mph.
Elewhere, sunbreaks will promote hit or miss light snow showers.
Under these showers, expect brief MVFR to locally IFR conditions.
Stratus will be the more dominate nuisance overnight frm Spokane
to CDA given the weak NE push but a combination of fog and stratus
will be possible at the remaining terminals and carry low
confidence. The system driving the snow today will weaken this
evening and overnight period and we expect most snow showers to
be over by early Saturday. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 36 19 30 16 33 25 / 50 30 0 0 10 30
Coeur d`Alene 35 18 30 14 34 24 / 90 40 10 0 10 20
Pullman 35 22 31 18 34 24 / 20 20 10 0 0 20
Lewiston 41 27 35 22 38 30 / 20 10 10 0 0 20
Colville 37 22 33 17 36 25 / 90 40 0 0 10 30
Sandpoint 35 19 29 11 33 21 / 90 30 0 0 10 10
Kellogg 34 20 27 15 30 22 / 90 70 10 0 0 0
Moses Lake 43 22 36 20 38 27 / 10 0 0 0 0 50
Wenatchee 43 28 37 23 37 29 / 20 10 10 0 0 50
Omak 42 24 36 21 37 27 / 10 10 0 0 10 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 4 PM PST this afternoon for
Central Panhandle Mountains-Northern Panhandle.
WA...Winter Weather Advisory until 4 PM PST this afternoon for
Northeast Mountains-Okanogan Highlands.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
253 PM CST FRI NOV 9 2012
.SHORT TERM...TONIGHT AND SATURDAY.
THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE LOW
PRESSURE EMERGING INTO THE CENTRAL GREAT PLAINS AND A WARM FRONT
SNAKING ITS WAY ACROSS KANSAS...NORTHERN MISSOURI...AND CENTRAL
ILLINOIS. AN 850MB DEFORMATION ZONE EXISTS OVER NORTHERN WISCONSIN
EARLY THIS AFTERNOON...AND THE CONVERGENCE IS HELPING TO CREATE
WIDESPREAD CLOUD COVER. SCT SHOWERS DEVELOPED EARLIER TODAY OVER
CENTRAL LAKE MICHIGAN ON THE NOSE OF A WEAK LOW LEVEL JET BUT THEY
HAVE SINCE MOVED ON INTO LOWER MICHIGAN. AS THE WARM FRONT LIFTS
NORTH TONIGHT AND SATURDAY...PRECIP AND THUNDER CHANCES ARE THE MAIN
FORECAST CONCERNS.
TONIGHT...AS HEIGHT FALLS OCCUR OVER THE WESTERN GREAT PLAINS WITH
THE APPROACH OF THE LARGE WESTERN CONUS TROUGH...WARM ADVECTION WILL
RAMP UP FROM THE NORTHERN MISSISSIPPI VALLEY TO THE EASTERN GREAT
LAKES TONIGHT. CURRENT LLJ OVER SOUTHERN LAKE MICHIGAN/SE LOWER
MICHIGAN AND ILLINOIS WILL BYPASS THE STATE AS IT SHIFTS TO THE
SOUTHEAST THIS EVENING. WILL HAVE TO WAIT FOR A SECONDARY AND
STRONGER LLJ TO ORGANIZE OVER THE SOUTHERN MISSOURI VALLEY AND LIFT
NORTHWARD LATE THIS EVENING FOR OUR MEANINGFUL PRECIP CHANCES TO
ARRIVE. OPERATIONAL MODELS THIS MORNING ARE DELAYING PRECIP CHANCES
AS IT LOOKS LIKE WEAK ISENTROPIC ASCENT THIS EVENING WILL GO TOWARDS
TRYING TO SATURATE THE COLUMN. HAVE TRIMMED POPS ACROSS THE NORTH
AS A RESULT. STRONGER ISENTROPIC ASCENT AND MOISTURE TRANSPORT THEN
ARRIVES AFTER MIDNIGHT AND HAVE INCREASED POPS TO LIKELY EVERYWHERE
EXCEPT NEAR THE U.P. BORDER. SHOULD ALSO SEE AREAS OF FOG DEVELOP
ONCE THE RAIN ARRIVES AS WELL. LOOKED AT THUNDER CHANCES TONIGHT
AND BUFKIT SOUNDINGS SHOW MID-LEVEL CAPPING AROUND 8KFT SO WILL KEEP
THUNDER OUT OF THE FORECAST. LOWS WILL STAY MILD AND RANGE FROM THE
MID 30S NORTH TO MID 40 SOUTHEAST.
SATURDAY...SURFACE LOW PRESSURE WILL TRACK NORTHEAST ACROSS THE
PLAINS INTO SOUTHERN MINNESOTA IN THE AFTERNOON. AHEAD OF THE
LOW...SW FLOW ALOFT WILL STRENGTHEN WHICH WILL INCREASE POP CHANCES
FOR THE MORNING INTO THE LIKELY/DEFINITE RANGE. AREAS OF FOG WILL
ALSO REMAIN AN ISSUE UNTIL DIURNAL HEATING CAN INCREASE THE
TEMPERATURE-DEWPOINT SPREAD BY LATE MORNING. MOST OF THE FORCING
SHOULD LIFT NORTH OF THE U.P. BORDER BY MID-AFTERNOON...WHICH SHOULD
END THE WIDESPREAD SHOWER THREAT. THE SURFACE WARM FRONT WILL LAG
BEHIND A BIT AND MOVE INTO CENTRAL WISCONSIN IN THE AFTERNOON.
TEMPS WILL BE THE WARMEST THERE...AND REACH INTO THE LOWER TO MIDDLE
60S. CAPPING ALSO DIMINISHES WITH THE APPROACH OF THE SURFACE WARM
FRONT...SO WILL LEAVE A MENTION OF ISOLATED THUNDER IN THE FORECAST.
.LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY. SHOWERS AND
ELEVATED THUNDERSTORMS POSSIBLE SATURDAY EVENING AS A WARM FRONT
MOVES INTO THE UPPER PENINSULA. THEN THERE WILL LIKELY BE LIGHHT
RAIN OR DRIZZLE LATE SATURDAY NIGHT AND SUNDAY ALONG WITH SOME
FOG. SURFACE WAVE MOVING NORTH ALONG A SLOW MOVING COLD FRONT
SHOULD PRODUCE A GOOD RAINFALL SUNDAY. THE RAIN WILL CHANGE TO
SNOW SUNDAY NIGHT OVER THE WESTERN PORTION OF THE FORECAST AREA
BUT ANY ACCUMULATIONS SHOULD BE LIGHT. BLUSTERY AND COLDER MONDAY
WITH CYCLONIC UPPER FLOW AND SCATTERED SNOW SHOWERS OR FLURRIES.
WINDS APPEAR TOO WESTERLY FOR LAKE EFFECT IN NORTHCENTRAL
WISCONSIN. DRY AND COOL TUESDAY THROUGH THURSDAY WITH UPPER FLOW
BECOMING ZONAL AND A SURFACE HIGH DRIFTING ACROSS THE AREA. SOME
CHANCE OF LIGHT PRECIPITATION TOWARDS THE END OF THE WEEK IN WARM
ADVECTION PATTERN BUT NOT MUCH MOISTURE SO LEFT IT DRY FRIDAY. &&
.AVIATION...SPOTTY MVFR CIGS OVER NORTHERN WISCONSIN WILL IMPROVE TO
VFR THIS AFTERNOON. THEN...A WARM FRONT WILL BE LIFTING NORTHWARD
ACROSS THE REGION LATE TONIGHT INTO SATURDAY. CIGS AND VSBYS WILL
BE FALLING MID-EVENING ONWARD AS LOW LEVEL MOISTURE INCREASES AHEAD
OF THIS FRONT. SHOWER/DRIZZLE CHANCES WILL ALSO IMPROVE THROUGH THE
NIGHT AS WELL. ONCE THE SHOWERS ARRIVE...CIGS AND VSBYS ARE
EXPECTED TO FALL INTO THE LIFR RANGE. SOME IMPROVEMENT EXPECTED BY
THE END OF THE TAF PERIOD AS SHOWERS LIFT OFF TO THE NORTHEAST.
MPC
&&
.MARINE...GUSTY SOUTH WINDS AND BUILDING WAVES MAY BE A HAZARD TO
SMALL CRAFT SATURDAY THROUGH EARLY SUNDAY. A COLD FRONT WILL MOVE
THROUGH SUNDAY AFTERNOON WITH GUSTY WEST WINDS AND LARGE WAVES
POSSIBLE FOLLOWING IT SUNDAY NIGHT AND MONDAY. &&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
RDM/MPC
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1218 PM MST FRI NOV 9 2012
.DISCUSSION...
IN A RECENT UPDATE HAVE ADDED SOUTHWEST CARBON COUNTY TO THE HIGH
WIND WARNING. KCOW HAS HAD GUSTS TO ABOVE 55 MPH SINCE 17Z. THE
WINDS AT KARL HAVE ALSO STARTED TO INCREASE...BUT GRADIENT MAY BE
TOO SOUTHERLY FOR THAT LOCATION FOR HIGH WINDS.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 1105 AM MST FRI NOV 9 2012/...
.UPDATE...WINDS CONTINUE TO INCREASE OVER MAINLY THE WEST PART
OF THE CWA AT MID MORNING. AS OF 17Z...SOME LOCATIONS HAD
SUSTAINED WINDS BETWEEN 35 AND 40 MPH AND GUSTS BETWEEN 50 AND 55
MPH. THOSE PLACES INCLUDE KRWL AS WELL AS LOCATIONS ALONG OR NEAR
INTERSTATE 80 FROM KARL TO KRWL. WITH THE FAST MID LEVEL FLOW ABLE
TO MIX TODAY... WILL CONTINUE TO PREVIOUSLY ISSUED HIGH WIND
WARNING FOR THAT AREA.
THE OTHER CONCERN FOR THE REST OF THE DAY IS THE DURATION OF THE
LOW CLOUDS AND FOG OVER THE EAST PART OF THE CWA. SOUTHEAST WIND
FLOW AND WARMING TEMPERATURES IN THE MID LEVELS SHOULD COMBINE TO
KEEP THE LOW CLOUDS OVER MOST OF THAT AREA THROUGH THE EARLY
AFTERNOON. CLOUD BASES WILL SLOWLY LIFT OVER THAT TIME WITH
CLEARING ALREADY TAKING PLACE AT KIBM AND JUST OCCURRED AT KSNY.
THE SLOW IMPROVEMENT IS SHOWN ON THE LATEST HRRR AS WELL AS TIME
HEIGHT PLOTS FOR THOSE AREAS. FOG CONTINUES TO SLOWLY LIFT OVER
THAT AREA WITH THE VISIBILITIES NOW BETWEEN 3 AND 6 MILES. THE LOW
CLOUDS SHOULD KEEP HIGH TEMPERATURES LOWER THAN EXPECTED OVER THE
PANHANDLE. MEANWHILE...FURTHER WEST...TEMPERATURES ARE ALREADY
APPROACHING FORECAST HIGHS AND SO HAVE BUMPED UP AFTERNOON HIGHS IN
THOSE AREAS.
&&
.AVIATION...18Z TAFS. THROUGH 01Z...STRONG SOUTHWEST WINDS SUSTAINED
NEAR 40 KNOTS GUSTING TO 50 KNOTS AT RAWLINS. THROUGH 00Z...VFR
WITH SURFACE LOW STRENGTHENING ACROSS WESTERN WYOMING NEAR
THERMOPOLIS...PRODUCING INCREASING SOUTH AND SOUTHEAST WINDS ACROSS
TAF SITES. AFTER 00Z...SURFACE LOW DEVELOPING FROM NORTHEAST
COLORADO TO NORTH CENTRAL NEBRASKA WITH A COLD FRONT MOVING EASTWARD
AND STRETCHING FROM CHADRON TO FORT COLLINS BY 12Z SATURDAY.
AFTER 04Z...SCATTERED SNOW SHOWERS AND AREAS OF FOG AT RAWLINS
PRODUCING IFR AND MVFR AND MOUNTAIN OBSCUREMENT. VFR ELSEWHERE.
AFTER 15Z...WINDS BECOMING NORTH AND NORTHWEST AFTER COLD FRONTAL
PASSAGE AND INCREASING WITH WINDS GUSTING TO 30 KNOTS. SCATTERED
SHOW SHOWERS PRODUCING MVFR AT RAWLINS TAF WITH VFR AT OTHER
SITES. RUBIN
&&
.PREV DISCUSSION... /ISSUED 509 AM MST FRI NOV 9 2012/
SHORT TERM...TODAY THROUGH SUNDAY NIGHT...
MAIN FORECAST FOCUS WAS GIVEN TO THE HIGH WIND POTENTIAL ACROSS
PORTIONS OF CARBON COUNTY TODAY AND THE RETURN TO WINTRY WEATHER ON
SATURDAY.
BEFORE THEN...EARLY MORNING 11-3.9 FOG PRODUCT SHOWS THE EDGE OF
FOG/LOW STRATUS SLOWLY PROGRESSING WEST ALONG A LUSK TO BRIDGEPORT
LINE. MODELS DO NOT SUGGEST MUCH FURTHER MOVEMENT WEST OF THIS
FOG...SO FOR NOW HAVE KEPT IT EAST OF LUSK/SCOTTSBLUFF/SIDNEY.
ALTHOUGH...WILL NEED TO WATCH THIS CLOSELY THROUGH SUNRISE.
ATTENTION THEN TURNS TO THE UPSTREAM HIGH AMPLITUDE TROUGH THAT WILL
MOVE FROM THE WEST COAST TODAY INTO THE INTERMOUNTAIN WEST TONIGHT
AND SATURDAY. STRONG SOUTHWEST FLOW OUT AHEAD OF THIS TROUGH WILL
BECOME COUPLED TODAY AS THE MIXED LAYER DEEPENS. MEANWHILE...SFC
PRESSURE FALLS ACROSS CENTRAL WYOMING SHOULD FURTHER STRENGTHEN THE
LLVL GRADIENT LATER TODAY. ALTHOUGH AN ATYPICAL HIGH WIND
PATTERN...EXPECT TO SEE THE 50 TO 55 KNOTS OF WINDS AT THE TOP OF
THE MIXED LAYER BE REALIZED LATER THIS MORNING AND DURING THE
AFTERNOON HOURS. SO...HAVE WENT AHEAD AND UPGRADED TO A HIGH WIND
WARNING ACROSS MOST LOWER ELEVATIONS OF CARBON COUNTY TODAY. WINDS
WILL DECOUPLE THROUGH THE EVENING...SO EXPECT THE STRONGEST WINDS TO
SUBSIDE THEN. OTHERWISE EXPECT CLOUDS TO BE ON THE INCREASE FOR MOST
LOCATIONS THROUGH THE DAY AS PACIFIC MOISTURE STREAMS AHEAD OF THE
TROUGH. ONE MORE MILD DAY IN STORE TODAY...THE LIKES OF WHICH WE
WONT SEE AGAIN AT LEAST FOR THE NEXT 7 DAYS. UPSTREAM 00Z SOUNDINGS
HAVE A BROAD AREA OF 5C AT H7...SO EXPECT 50S AND LOW 60S FOR HIGHS
TODAY.
BY TONIGHT...SFC LOW WILL DEEPEN AS IT SLIDES SOUTHEAST ACROSS THE
CWFA. THIS WILL PULL THE COLD FRONT SOUTH INTO NRN ZONES BY AROUND
MIDNIGHT AND THROUGH THE REST OF THE CWFA SATURDAY MORNING.
INITIALLY..SNOW WILL DEVELOP AS A RESULT OF AROUND 40 KNOTS OF
MOIST H7 SOUTHWESTERLY FLOW INTO THE SNOWY/SIERRA MADRES LATE
THIS EVENING. AS THE SFC FRONT DEEPENS AND THE FAVORABLE LFQ OF H3
ARRIVES ON SATURDAY...WILL BEGIN TO SEE PRECIPITATION SPILL OUT
INTO LOWER ELEVATIONS. TEMPERATURES MAY BE WARM ENOUGH TO SEE A
PERIOD OF LIGHT RAIN INITIALLY...ESPECIALLY OVER THE SRN NE
PANHANDLE. HOWEVER CHANGE-OVER WILL OCCUR QUICKLY AS COLD AIR
FILTERS IN BEHIND THE COLD FROPA. WILL NEED TO WATCH THIS CLOSELY
AS ANY RAIN OUT AHEAD OF THE COLD FRONT MAY CREATE SLIPPERY
DRIVING CONDITIONS. THE BEST H7-H5 FRONTOGENESIS WILL BECOME
JUXTAPOSED WITH BEST JET SUPPORT ON SATURDAY AFTERNOON/EVENING
SUGGESTING THAT THE BEST SNOW POTENTIAL WILL OCCUR THEN. 00Z MODEL
OUTPUT CONTINUES TO TREND TOWARDS A SPLIT TROUGH SOLUTION WHICH
WILL LIMIT SNOWFALL POTENTIAL. ONLY TRENDED TOWARDS THIS DRIER
SOLUTION AND WILL AWAIT FURTHER CONFIRMATION FROM SUBSEQUENT RUNS.
STILL THINK THAT AN INCH OR TWO WILL CATCH MOST OF THE LOWER
ELEVATIONS...WITH PERHAPS UP TO 3 IN AREAS CLOSEST TO THE
MOUNTAINS. THE SNOWIES/SIERRA MADRES WILL FARE THE BEST WITH 6 TO
10 INCHES EXPECTED WITH HIGHER AMOUNTS POSSIBLE ALONG WEST FACING
SLOPES. SO...DID ISSUE A WINTER WEATHER ADVISORY FOR THAT AREA
BEGINNING AT 9 PM TONIGHT AND CONTINUING THROUGH MIDNIGHT SATURDAY
NIGHT. THE UPPER TROUGH WILL REMAIN OVER THE AREA ON
SUNDAY...WHICH SHOULD RESULT IN SOME RESIDUAL SNOW SHOWERS
ESPECIALLY OVER THE MOUNTAINS. OTHERWISE...EXPECT A GENERALLY DRY
DAY FOR SUNDAY.
THE OTHER MAJOR IMPACT FROM THIS SYSTEM WILL BE THE FRIGID AIR MASS
THAT WILL USHER IN THE COLDEST AIR THUS FAR THIS SEASON. H7
TEMPERATURES OF -14C TO -16C WILL PREVENT HIGH TEMPERATURES FROM
CLIMBING OUT OF THE 20S AT MOST LOCATIONS ON SUNDAY.
LIKEWISE...OVERNIGHT LOW TEMPERATURES WILL DIP INTO THE SINGLE
DIGITS AND TEENS FOR BOTH SATURDAY AND SUNDAY NIGHTS. WOULD NOT BE
AT ALL SURPRISED FOR SHELTERS VALLEYS WEST OF THE LARAMIE RANGE TO
FALL BELOW ZERO...ESPECIALLY ON SUNDAY NIGHT.
LONG TERM...MONDAY THROUGH FRIDAY...UPPER LEVEL WINDS WILL BACK TO
THE WEST ON MONDAY AS A BROAD RIDGE BUILDS OVER THE WESTERN CONUS
FOR MONDAY THROUGH WEDNESDAY. EXPECTING DRY CONDITIONS UNDER
PARTLY TO MOSTLY CLOUDY SKIES AS A MID/HIGH LEVEL CLOUD DECK
STREAMS OVERHEAD IN THIS ZONAL PATTERN. WINDS WILL REMAIN BREEZY
ALONG AND WEST OF THE LARAMIE RANGE THROUGH THIS TIME AS WELL WITH
THE RIDGE BUILDING IN FROM THE WEST. 700MB TEMPERATURES WILL
STEADILY CLIMB THROUGH THE WEEK BACK TO NEAR 0C BY WEDNESDAY...SO
EXPECTING HIGH TEMPS TO BECOME MORE NORMAL FOR THIS TIME OF YEAR
THROUGH THE WEEKEND. THE NEXT SYSTEM WILL MOVE ACROSS THE ROCKIES
THURSDAY NIGHT AND FRIDAY...DRAGGING A COLD FRONT THROUGH THE
FORECAST AREA EARLY FRIDAY MORNING. 00Z ECMWF IS QUITE A BIT
SLOWER THAN THE 00Z GFS...PREVIOUS RUNS...AND THE GFS ENSEMBLE
MEAN...SO WILL DISCOUNT THE 00Z ECMWF FOR THIS FORECAST. THE MAIN
UPPER TROUGH AXIS MOVES OVERHEAD 06Z FRIDAY WITH FLOW ALOFT
BECOMING SOUTHWEST AHEAD OF THE TROUGH. THE LEESIDE SFC TROUGH
WILL DEEPEN AHEAD OF THE UPPER TROUGH AS WELL WITH SOUTHEAST SFC
FLOW STRENGTHENING ACROSS THE EASTERN PLAINS ON THURSDAY. THE COLD
FRONT WILL MOVE EAST EARLY FRIDAY MORNING WITH SLIGHTLY COOLER
TEMPS EXPECTED FOR FRIDAY. MOIST SOUTHWEST FLOW AHEAD OF THE
TROUGH WILL BRING A SLIGHT CHANCE FOR RAIN/SNOW SHOWERS ALONG THE
WESTERN SLOPES OF THE MOUNTAINS BEGINNING THURSDAY AND CONTINUING
THE WEEKEND.
AVIATION...12Z TAF ISSUANCE...STRONG WEST TO SOUTHWEST WINDS ARE
EXPECTED TODAY ALONG AND WEST OF THE LARAMIE RANGE...WITH GUSTS
IN EXCESS OF 45 KTS EXPECTED FROM RAWLINS TO ARLINGTON. THESE WINDS
WILL EASE OVERNIGHT. ACROSS THE EAST...WIND WILL BE OUT OF THE
SOUTHEAST AT 10 TO 15 KTS...WITH IFR CIGS AND VSBYS ACROSS THE
NORTHERN PANHANDLE SITES THROUGH MIDMORNING. EXPECTING VFR THEN TO
RETURN FOR THE REMAINDER OF THE PERIOD IN THE EAST. A LOW PRESSURE
SYSTEM MOVING ACROSS THE REGION TONIGHT AND SATURDAY WILL BRING
SNOW TO THE MOUNTAINS LATE TONIGHT THROUGH TOMORROW...WITH SNOW
SPREADING INTO THE EASTERN PLAINS ON SATURDAY MORNING. LIKELY
TO SEE MVFR TO IFR DEVELOPING SATURDAY WITH OBSCURED MOUNTAINS.
FIRE WEATHER...ONE MORE MILD DAY IN STORE ACROSS THE DISTRICT
TODAY AS THE NEXT STORM SYSTEM BEARS DOWN ON THE REGION LATER
TONIGHT AND CONTINUING INTO THE WEEKEND. WINDY CONDITIONS WILL
DEVELOP TODAY ACROSS LOWER ELEVATIONS OF CARBON COUNTY WITH GUSTS
APPROACHING 60 MPH. THESE WILL SUBSIDE THIS EVENING AS A COLD
FRONT BEGINS TO WORK THROUGH. THIS FRONTAL SYSTEM WILL BRING SNOW
TO THE SNOWIES/SIERRA MADRES TONIGHT...SPILLING OUT ONTO THE
PLAINS ON SATURDAY. SNOWFALL AMOUNTS OF GENERALLY 1 TO 3 INCHES
WILL BE POSSIBLE ACROSS LOWER ELEVATIONS...WITH 6 TO 10 INCHES
ACROSS IN THE SNOWIES/SIERRA MADRES. SNOW WILL BEGIN TO WIND DOWN
LATE SATURDAY NIGHT...GIVING WAY TO MOSTLY DRY CONDITIONS ON
SUNDAY. TEMPERATURES WILL BECOME MUCH COLDER BEHIND THE COLD FRONT
HIGH TEMPERATURES ONLY CLIMBING INTO THE 30S ON SATURDAY...AND 20S
FOR SUNDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...HIGH WIND WARNING UNTIL 6 PM FRIDAY FOR WYZ104-WYZ109-WYZ110-
WYZ111.
WINTER WEATHER ADVISORY FROM 9 PM FRIDAY TO MIDNIGHT SUNDAY FOR
WYZ112-WYZ114.
NE...NONE.
&&
$$
UPDATE...WEILAND
SHORT TERM/FIRE WEATHER...HAHN
LONG TERM/AVIATION...RJM
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1105 AM MST FRI NOV 9 2012
.UPDATE...WINDS CONTINUE TO INCREASE OVER MAINLY THE WEST PART
OF THE CWA AT MID MORNING. AS OF 17Z...SOME LOCATIONS HAD
SUSTAINED WINDS BETWEEN 35 AND 40 MPH AND GUSTS BETWEEN 50 AND 55
MPH. THOSE PLACES INCLUDE KRWL AS WELL AS LOCATIONS ALONG OR NEAR
INTERSTATE 80 FROM KARL TO KRWL. WITH THE FAST MID LEVEL FLOW ABLE
TO MIX TODAY... WILL CONTINUE TO PREVIOUSLY ISSUED HIGH WIND
WARNING FOR THAT AREA.
THE OTHER CONCERN FOR THE REST OF THE DAY IS THE DURATION OF THE
LOW CLOUDS AND FOG OVER THE EAST PART OF THE CWA. SOUTHEAST WIND
FLOW AND WARMING TEMPERATURES IN THE MID LEVELS SHOULD COMBINE TO
KEEP THE LOW CLOUDS OVER MOST OF THAT AREA THROUGH THE EARLY
AFTERNOON. CLOUD BASES WILL SLOWLY LIFT OVER THAT TIME WITH
CLEARING ALREADY TAKING PLACE AT KIBM AND JUST OCCURRED AT KSNY.
THE SLOW IMPROVEMENT IS SHOWN ON THE LATEST HRRR AS WELL AS TIME
HEIGHT PLOTS FOR THOSE AREAS. FOG CONTINUES TO SLOWLY LIFT OVER
THAT AREA WITH THE VISIBILITIES NOW BETWEEN 3 AND 6 MILES. THE LOW
CLOUDS SHOULD KEEP HIGH TEMPERATURES LOWER THAN EXPECTED OVER THE
PANHANDLE. MEANWHILE...FURTHER WEST...TEMPERATURES ARE ALREADY
APPROACHING FORECAST HIGHS AND SO HAVE BUMPED UP AFTERNOON HIGHS IN
THOSE AREAS.
&&
.AVIATION...18Z TAFS. THROUGH 01Z...STRONG SOUTHWEST WINDS SUSTAINED
NEAR 40 KNOTS GUSTING TO 50 KNOTS AT RAWLINS. THROUGH 00Z...VFR
WITH SURFACE LOW STRENGTHENING ACROSS WESTERN WYOMING NEAR
THERMOPOLIS...PRODUCING INCREASING SOUTH AND SOUTHEAST WINDS ACROSS
TAF SITES. AFTER 00Z...SURFACE LOW DEVELOPING FROM NORTHEAST
COLORADO TO NORTH CENTRAL NEBRASKA WITH A COLD FRONT MOVING EASTWARD
AND STRETCHING FROM CHADRON TO FORT COLLINS BY 12Z SATURDAY.
AFTER 04Z...SCATTERED SNOW SHOWERS AND AREAS OF FOG AT RAWLINS
PRODUCING IFR AND MVFR AND MOUNTAIN OBSCUREMENT. VFR ELSEWHERE.
AFTER 15Z...WINDS BECOMING NORTH AND NORTHWEST AFTER COLD FRONTAL
PASSAGE AND INCREASING WITH WINDS GUSTING TO 30 KNOTS. SCATTERED
SHOW SHOWERS PRODUCING MVFR AT RAWLINS TAF WITH VFR AT OTHER
SITES. RUBIN
&&
.PREV DISCUSSION... /ISSUED 509 AM MST FRI NOV 9 2012/
SHORT TERM...TODAY THROUGH SUNDAY NIGHT...
MAIN FORECAST FOCUS WAS GIVEN TO THE HIGH WIND POTENTIAL ACROSS
PORTIONS OF CARBON COUNTY TODAY AND THE RETURN TO WINTRY WEATHER ON
SATURDAY.
BEFORE THEN...EARLY MORNING 11-3.9 FOG PRODUCT SHOWS THE EDGE OF
FOG/LOW STRATUS SLOWLY PROGRESSING WEST ALONG A LUSK TO BRIDGEPORT
LINE. MODELS DO NOT SUGGEST MUCH FURTHER MOVEMENT WEST OF THIS
FOG...SO FOR NOW HAVE KEPT IT EAST OF LUSK/SCOTTSBLUFF/SIDNEY.
ALTHOUGH...WILL NEED TO WATCH THIS CLOSELY THROUGH SUNRISE.
ATTENTION THEN TURNS TO THE UPSTREAM HIGH AMPLITUDE TROUGH THAT WILL
MOVE FROM THE WEST COAST TODAY INTO THE INTERMOUNTAIN WEST TONIGHT
AND SATURDAY. STRONG SOUTHWEST FLOW OUT AHEAD OF THIS TROUGH WILL
BECOME COUPLED TODAY AS THE MIXED LAYER DEEPENS. MEANWHILE...SFC
PRESSURE FALLS ACROSS CENTRAL WYOMING SHOULD FURTHER STRENGTHEN THE
LLVL GRADIENT LATER TODAY. ALTHOUGH AN ATYPICAL HIGH WIND
PATTERN...EXPECT TO SEE THE 50 TO 55 KNOTS OF WINDS AT THE TOP OF
THE MIXED LAYER BE REALIZED LATER THIS MORNING AND DURING THE
AFTERNOON HOURS. SO...HAVE WENT AHEAD AND UPGRADED TO A HIGH WIND
WARNING ACROSS MOST LOWER ELEVATIONS OF CARBON COUNTY TODAY. WINDS
WILL DECOUPLE THROUGH THE EVENING...SO EXPECT THE STRONGEST WINDS TO
SUBSIDE THEN. OTHERWISE EXPECT CLOUDS TO BE ON THE INCREASE FOR MOST
LOCATIONS THROUGH THE DAY AS PACIFIC MOISTURE STREAMS AHEAD OF THE
TROUGH. ONE MORE MILD DAY IN STORE TODAY...THE LIKES OF WHICH WE
WONT SEE AGAIN AT LEAST FOR THE NEXT 7 DAYS. UPSTREAM 00Z SOUNDINGS
HAVE A BROAD AREA OF 5C AT H7...SO EXPECT 50S AND LOW 60S FOR HIGHS
TODAY.
BY TONIGHT...SFC LOW WILL DEEPEN AS IT SLIDES SOUTHEAST ACROSS THE
CWFA. THIS WILL PULL THE COLD FRONT SOUTH INTO NRN ZONES BY AROUND
MIDNIGHT AND THROUGH THE REST OF THE CWFA SATURDAY MORNING.
INITIALLY..SNOW WILL DEVELOP AS A RESULT OF AROUND 40 KNOTS OF
MOIST H7 SOUTHWESTERLY FLOW INTO THE SNOWY/SIERRA MADRES LATE
THIS EVENING. AS THE SFC FRONT DEEPENS AND THE FAVORABLE LFQ OF H3
ARRIVES ON SATURDAY...WILL BEGIN TO SEE PRECIPITATION SPILL OUT
INTO LOWER ELEVATIONS. TEMPERATURES MAY BE WARM ENOUGH TO SEE A
PERIOD OF LIGHT RAIN INITIALLY...ESPECIALLY OVER THE SRN NE
PANHANDLE. HOWEVER CHANGE-OVER WILL OCCUR QUICKLY AS COLD AIR
FILTERS IN BEHIND THE COLD FROPA. WILL NEED TO WATCH THIS CLOSELY
AS ANY RAIN OUT AHEAD OF THE COLD FRONT MAY CREATE SLIPPERY
DRIVING CONDITIONS. THE BEST H7-H5 FRONTOGENESIS WILL BECOME
JUXTAPOSED WITH BEST JET SUPPORT ON SATURDAY AFTERNOON/EVENING
SUGGESTING THAT THE BEST SNOW POTENTIAL WILL OCCUR THEN. 00Z MODEL
OUTPUT CONTINUES TO TREND TOWARDS A SPLIT TROUGH SOLUTION WHICH
WILL LIMIT SNOWFALL POTENTIAL. ONLY TRENDED TOWARDS THIS DRIER
SOLUTION AND WILL AWAIT FURTHER CONFIRMATION FROM SUBSEQUENT RUNS.
STILL THINK THAT AN INCH OR TWO WILL CATCH MOST OF THE LOWER
ELEVATIONS...WITH PERHAPS UP TO 3 IN AREAS CLOSEST TO THE
MOUNTAINS. THE SNOWIES/SIERRA MADRES WILL FARE THE BEST WITH 6 TO
10 INCHES EXPECTED WITH HIGHER AMOUNTS POSSIBLE ALONG WEST FACING
SLOPES. SO...DID ISSUE A WINTER WEATHER ADVISORY FOR THAT AREA
BEGINNING AT 9 PM TONIGHT AND CONTINUING THROUGH MIDNIGHT SATURDAY
NIGHT. THE UPPER TROUGH WILL REMAIN OVER THE AREA ON
SUNDAY...WHICH SHOULD RESULT IN SOME RESIDUAL SNOW SHOWERS
ESPECIALLY OVER THE MOUNTAINS. OTHERWISE...EXPECT A GENERALLY DRY
DAY FOR SUNDAY.
THE OTHER MAJOR IMPACT FROM THIS SYSTEM WILL BE THE FRIGID AIR MASS
THAT WILL USHER IN THE COLDEST AIR THUS FAR THIS SEASON. H7
TEMPERATURES OF -14C TO -16C WILL PREVENT HIGH TEMPERATURES FROM
CLIMBING OUT OF THE 20S AT MOST LOCATIONS ON SUNDAY.
LIKEWISE...OVERNIGHT LOW TEMPERATURES WILL DIP INTO THE SINGLE
DIGITS AND TEENS FOR BOTH SATURDAY AND SUNDAY NIGHTS. WOULD NOT BE
AT ALL SURPRISED FOR SHELTERS VALLEYS WEST OF THE LARAMIE RANGE TO
FALL BELOW ZERO...ESPECIALLY ON SUNDAY NIGHT.
LONG TERM...MONDAY THROUGH FRIDAY...UPPER LEVEL WINDS WILL BACK TO
THE WEST ON MONDAY AS A BROAD RIDGE BUILDS OVER THE WESTERN CONUS
FOR MONDAY THROUGH WEDNESDAY. EXPECTING DRY CONDITIONS UNDER
PARTLY TO MOSTLY CLOUDY SKIES AS A MID/HIGH LEVEL CLOUD DECK
STREAMS OVERHEAD IN THIS ZONAL PATTERN. WINDS WILL REMAIN BREEZY
ALONG AND WEST OF THE LARAMIE RANGE THROUGH THIS TIME AS WELL WITH
THE RIDGE BUILDING IN FROM THE WEST. 700MB TEMPERATURES WILL
STEADILY CLIMB THROUGH THE WEEK BACK TO NEAR 0C BY WEDNESDAY...SO
EXPECTING HIGH TEMPS TO BECOME MORE NORMAL FOR THIS TIME OF YEAR
THROUGH THE WEEKEND. THE NEXT SYSTEM WILL MOVE ACROSS THE ROCKIES
THURSDAY NIGHT AND FRIDAY...DRAGGING A COLD FRONT THROUGH THE
FORECAST AREA EARLY FRIDAY MORNING. 00Z ECMWF IS QUITE A BIT
SLOWER THAN THE 00Z GFS...PREVIOUS RUNS...AND THE GFS ENSEMBLE
MEAN...SO WILL DISCOUNT THE 00Z ECMWF FOR THIS FORECAST. THE MAIN
UPPER TROUGH AXIS MOVES OVERHEAD 06Z FRIDAY WITH FLOW ALOFT
BECOMING SOUTHWEST AHEAD OF THE TROUGH. THE LEESIDE SFC TROUGH
WILL DEEPEN AHEAD OF THE UPPER TROUGH AS WELL WITH SOUTHEAST SFC
FLOW STRENGTHENING ACROSS THE EASTERN PLAINS ON THURSDAY. THE COLD
FRONT WILL MOVE EAST EARLY FRIDAY MORNING WITH SLIGHTLY COOLER
TEMPS EXPECTED FOR FRIDAY. MOIST SOUTHWEST FLOW AHEAD OF THE
TROUGH WILL BRING A SLIGHT CHANCE FOR RAIN/SNOW SHOWERS ALONG THE
WESTERN SLOPES OF THE MOUNTAINS BEGINNING THURSDAY AND CONTINUING
THE WEEKEND.
AVIATION...12Z TAF ISSUANCE...STRONG WEST TO SOUTHWEST WINDS ARE
EXPECTED TODAY ALONG AND WEST OF THE LARAMIE RANGE...WITH GUSTS
IN EXCESS OF 45 KTS EXPECTED FROM RAWLINS TO ARLINGTON. THESE WINDS
WILL EASE OVERNIGHT. ACROSS THE EAST...WIND WILL BE OUT OF THE
SOUTHEAST AT 10 TO 15 KTS...WITH IFR CIGS AND VSBYS ACROSS THE
NORTHERN PANHANDLE SITES THROUGH MIDMORNING. EXPECTING VFR THEN TO
RETURN FOR THE REMAINDER OF THE PERIOD IN THE EAST. A LOW PRESSURE
SYSTEM MOVING ACROSS THE REGION TONIGHT AND SATURDAY WILL BRING
SNOW TO THE MOUNTAINS LATE TONIGHT THROUGH TOMORROW...WITH SNOW
SPREADING INTO THE EASTERN PLAINS ON SATURDAY MORNING. LIKELY
TO SEE MVFR TO IFR DEVELOPING SATURDAY WITH OBSCURED MOUNTAINS.
FIRE WEATHER...ONE MORE MILD DAY IN STORE ACROSS THE DISTRICT
TODAY AS THE NEXT STORM SYSTEM BEARS DOWN ON THE REGION LATER
TONIGHT AND CONTINUING INTO THE WEEKEND. WINDY CONDITIONS WILL
DEVELOP TODAY ACROSS LOWER ELEVATIONS OF CARBON COUNTY WITH GUSTS
APPROACHING 60 MPH. THESE WILL SUBSIDE THIS EVENING AS A COLD
FRONT BEGINS TO WORK THROUGH. THIS FRONTAL SYSTEM WILL BRING SNOW
TO THE SNOWIES/SIERRA MADRES TONIGHT...SPILLING OUT ONTO THE
PLAINS ON SATURDAY. SNOWFALL AMOUNTS OF GENERALLY 1 TO 3 INCHES
WILL BE POSSIBLE ACROSS LOWER ELEVATIONS...WITH 6 TO 10 INCHES
ACROSS IN THE SNOWIES/SIERRA MADRES. SNOW WILL BEGIN TO WIND DOWN
LATE SATURDAY NIGHT...GIVING WAY TO MOSTLY DRY CONDITIONS ON
SUNDAY. TEMPERATURES WILL BECOME MUCH COLDER BEHIND THE COLD FRONT
HIGH TEMPERATURES ONLY CLIMBING INTO THE 30S ON SATURDAY...AND 20S
FOR SUNDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...HIGH WIND WARNING UNTIL 6 PM FRIDAY FOR WYZ104-WYZ109-WYZ110.
WINTER WEATHER ADVISORY FROM 9 PM FRIDAY TO MIDNIGHT SUNDAY FOR
WYZ112-WYZ114.
NE...NONE.
&&
$$
UPDATE...WEILAND
SHORT TERM/FIRE WEATHER...HAHN
LONG TERM/AVIATION...RJM