Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 04/17/12
AREA FORECAST DISCUSSION
NWS ALBANY NY
1031 PM EDT MON APR 16 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE REGION OVERNIGHT WITH
THE BEST CHANCE OF SHOWERS NORTH AND WEST OF THE CAPITAL DISTRICT.
AFTER THE COLD FRONTAL PASSAGE...A PERIOD OF DRY WEATHER IS EXPECTED
TUESDAY THROUGH THURSDAY WITH MORE SEASONABLE TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 1030 PM...THE COLD FRONT AND ITS ASSOCIATED PREFRONTAL SFC
TROUGH CONTINUE TO MOVE EASTWARD ACROSS W-CNTRL NY. THERE WERE A
FEW CG LTG STRIKES RIGHT OFF THE ERN SHORES OF LAKE ONTARIO A FEW
HOURS AGO...BUT SINCE THE LTG ACTIVITY HAS DIMINISHED. WE HAVE
REMOVED THUNDER FROM FCST DUE TO THE LACK OF INSTABILITY...AND LOW
LEVEL MOISTURE. WE HAVE SEEN A FEW WIND GUSTS UPSTREAM TO 30-35
KTS /KRME HAD A GUST TO 35 KTS AT 02Z/. WE INCREASED THE POPS TO
HIGH CHANCE AND LIKELY VALUES OVER THE SRN DACKS FOR A FEW HOURS
BASED ON THE RADAR TRENDS AT THIS TIME. THE LATEST HRRR AND NAM
INDICATE THIS AREA OF SHOWERS WILL SHRIVEL UP...AS IT HEADS EAST
INTO THE HUDSON RIVER VALLEY. THE LATEST 00Z KALB IS VERY DRY WITH
A STRONG INVERSION IN THE H700-600 LAYER. WE DID INCREASE THE
GUSTS TO 30-35 MPH WITH THE FRONTAL PASSAGE. TEMPS WERE ALSO
REDONE BASED ON THE HOURLY TRENDS...AND WE WENT A LITTLE COOLER
OVER THE NW ZONES WITH THE COLD AIR ADVECTION. EXPECT LOWS IN THE
40S NORTH AND WEST OF THE CAPITAL REGION...AND UPPER HUDSON
VALLEY...AND GENERALLY 50-55F SOUTH AND EAST...WITH A FEW MID AND
U40S OVER THE MTNS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY THROUGH THURSDAY IS EXPECTED TO BE DRY WITH MORE
SEASONABLE CONDITIONS AS IN THE WAKE OF THE COLD FRONT A LARGE
RIDGE OF HIGH PRESSURE WILL MOVE INTO THE REGION. SEE FIRE WEATHER
DISCUSSION BELOW FOR WINDS THE NEXT SEVERAL DAYS. THE OTHER
CONCERN IS FROST/FREEZE IN AREAS WHERE THE GROWING SEASON HAS
STARTED MOHAWK VALLEY...HUDSON VALLEY AND LITCHFIELD COUNTY IN
CONNECTICUT. AREAS OF FROST AND WIDESPREAD FROST HAVE BEEN
MENTIONED IN THE FORECAST FOR AREAS WHERE TEMPS ARE EXPECTED TO
DROP TO 33 TO 36 DEGREES AND 32 DEGREES OR BELOW RESPECTIVELY.
HIGHS ON TUESDAY ARE EXPECTED TO RANGE FROM THE MID 50S NORTHWEST
TO MID 70S SOUTHEAST...LOWS TUESDAY NIGHT IN THE MID 20S TO MID
30S...HIGHS ON WEDNESDAY IN THE MID 50S TO MID 60S...LOWS
WEDNESDAY NIGHT IN THE UPPER 20S TO MID 30S...AND HIGHS ON
THURSDAY IN THE 60S TO AROUND 70.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE EXTENDED FORECAST TRENDS TO A WET AND UNSETTLED STRETCH...WHICH
IS MORE TYPICAL OF APRIL...AS A CUTOFF LOW PRESSURE SITUATED NEAR
THE SOUTHEAST OR TN VALLEY COULD BRING A WIDESPREAD HEAVY RAINFALL
FOR THE WEEKEND INTO EARLY NEXT WEEK.
THE EXTENDED OPENS WITH ZONAL UPPER LEVEL FLOW OVER THE
NORTHEAST...AS HIGH PRESSURE RETREATS OFF THE NJ AND SRN NEW ENGLAND
COAST. A COLD FRONT SLOWLY DESCENDS SOUTH AND EAST FROM THE ST
LAWRENCE RIVER VALLEY THU NIGHT INTO FRIDAY. A WAVE APPROACHES ON
THE GFS/ECMWF FROM THE LOWER GREAT LAKES REGION FRIDAY MORNING...BUT
THE BETTER LIFT AND UPPER LEVEL JET DYNAMICS ARE NORTH AND WEST OF
THE FCST AREA OVER SE CANADA. WE GRADUALLY BROUGHT SLIGHT AND LOW
CHC POPS IN FOR THE REGION THU NIGHT INTO FRI. HPC BRINGS THE
FRONTAL BOUNDARY OVER THE CAPITAL REGION...AND CNTRL NEW ENGLAND BY
FRIDAY. WE WENT WITH THE HIGHER CHANCE POPS OVER THE NRN
ZONES...THOUGH THE ECMWF WOULD KEEP IT DRY TO CLOSE THE WEEK WITH
SOME MID AND UPPER RIDGING OFF THE EAST COAST BLOCKING THE FRONTAL
PASSAGE. LOWS THU NIGHT WILL GENERALLY BE IN THE 40S...AND HIGHS ON
FRIDAY WILL RANGE FROM THE U60S TO L70S MAINLY IN THE VALLEYS...AND
U50S TO M60S OVER THE HILLS AND MTNS. THESE ABOVE NORMAL TEMPS
LOOK ONLY TO LAST ONE MORE DAY.
FRIDAY NIGHT INTO SATURDAY...THE GFS/ECMWF/GEFS/HPC GRAPHICS ALL
INDICATE A DEVELOPING NEUTRAL TILTED LONG-WAVE TROUGH OVER THE MS
RIVER VALLEY. INITIALLY WEAK RIPPLES OF LOW PRESSURE MAY FORM ON
THE ERN SIDE OF TROUGH...AND THE OLD COLD FRONT WILL LIFT N/NE THAT
MAY BRING A THREAT OF SHOWERS TO THE FCST AREA DURING THIS TIME
FRAME. HOWEVER...THE MEDIUM RANGE GUIDANCE SHOWS THE UPPER TROUGH
CLOSING OFF OVER THE SOUTHEAST/TN VALLEY. THE GFS CLOSES THE UPPER
TROUGH OVER THE LOWER MS RIVER VALLEY FASTER THAN THE ECMWF /WHICH
IS FURTHER EAST/. LATE SATURDAY PM...A STRATIFORM RAINFALL MAY MOVE
INTO THE REGION...THOUGH WE CHANGED THE WX TYPE FROM SHOWERS FRI
NIGHT...TO RAIN ON SATURDAY.
SATURDAY NIGHT THROUGH SUNDAY NIGHT...WET AND UNSETTLED WX WILL
DOMINATE...AS AN AREA OF UPPER LEVEL DIFFLUENCE SETS UP OVER THE
NORTHEAST WITH MULTIPLE WAVES OF LOW PRESSURE ROTATING AROUND THE
H500 CUTOFF. THE GFS IS FURTHER INLAND AND WEST WITH THE MAIN SFC
CYCLONE FOR THE SECOND HALF OF THE WEEKEND...WHERE THE ECMWF AND HPC
GUIDANCE HAVE A COASTAL WAVE LIFTING N/NE FROM THE CAROLINAS ON
SUNDAY WITH A DEEP TRANSPORT OF SUBTROPICAL MOISTURE IN ADVANCE OF
IT. STRONG THERMAL ADVECTION AND QG LIFT AHEAD OF A WARM FRONT AND
THE COASTAL CYCLONE COULD BRING PERIODS OF MODERATE TO HVY
RAINFALL. WE KEPT HIGH CHANCE POPS IN THE FORECAST INTO EARLY
MONDAY...UNTIL CONFIDENCE INCREASES FOR THIS WIDESPREAD PCPN
POTENTIAL. THIS COULD BE THE WIDESPREAD SOAKING RAINFALL THE FCST
AREA NEEDS AFTER THE PERSISTENT DRY SPELL OVER THE PAST MONTH OR
SO. TEMPS WILL GENERALLY BE NEAR NORMAL OR SLIGHTLY ABOVE NORMAL IN
THE DAMP AIR MASS.
MONDAY...A CHANCE OF SHOWERS WILL PERSIST WITH THE STACKED CYCLONE
OVER THE UPPER MID ATLANTIC REGION. THERE ARE SOME SIGNS THE FCST
AREA COULD GET INTO A DRY SLOT FOR PART OF THE DAY. HOWEVER...WITH
SHORTWAVE ENERGY MOVING AROUND THE CUT-OFF SCT SHOWERS WILL STILL BE
POSSIBLE.
OVERALL...PCPN COULD BE WELL ABOVE NORMAL...AND TEMPS NEAR NORMAL IN
THE LONG TERM.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
EXPECT VFR CONDITIONS AT THE TAF SITES FOR THE ENTIRE TAF PERIOD
ENDING AT 00Z WEDNESDAY.
MAINLY SKC CONDITIONS WILL PREVAIL AT THE TAF SITES UNTIL JUST
BEFORE ARRIVAL OF THE COLD FRONT BETWEEN 04Z AND 06Z. SKIES WILL
MAINLY BE FEW-SCT040-050 SCT-BKN250 WITH COLD FRONTAL PASSAGE
THROUGH THE END OF TONIGHT AND THEN SCT250 OR SKC FROM LATE TONIGHT
THROUGH TUE.
SOUTH WINDS AT 10-14 KTS WITH GUSTS UP TO 20 KTS WILL SHIFT TO THE
WEST TO NORTHWEST AT 10-12 KTS WITH GUSTS TO 22 KTS...AND THEN
INCREASE BY TUESDAY AFTERNOON TO 12-15 KTS WITH GUSTS UP TO 30
KTS.
.OUTLOOK...
TUE NGT-THU NGT...MAINLY VFR...NO SIG WX.
FRI-SAT...CHC VFR/MVFR -SHRA.
&&
.FIRE WEATHER...
FIRE WEATHER WATCH IS IN EFFECT FROM NOON TO 8 PM EDT TUESDAY FOR
THE EASTERN MOHAWK VALLEY...SCHOHARIE VALLEY...GREATER CAPITAL
DISTRICT...SARATOGA REGION...MID HUDSON VALLEY...EASTERN
CATSKILLS...TACONICS...WESTERN MASSACHUSETTS...AND NORTHWESTERN
CONNECTICUT.
A COLD FRONT WILL CROSS THE REGION TONIGHT INTO EARLY TUESDAY MORNING
WITH THE BEST CHANCE OF SHOWERS...AND A FEW THUNDERSTORMS NORTH
AND WEST OF THE CAPITAL DISTRICT THIS EVENING. AFTER THE COLD
FRONTAL PASSAGE...A PERIOD OF DRY WEATHER IS EXPECTED TUESDAY
THROUGH THURSDAY WITH MORE SEASONABLE TEMPERATURES.
RELATIVE HUMIDITIES ARE EXPECTED TO RECOVER TO 70 TO 95 PERCENT TONIGHT
DROP TO 20 TO 35 PERCENT ON TUESDAY...RECOVER TO 65 TO 100
PERCENT TUESDAY NIGHT...AND DROP TO 20 TO 40 PERCENT ON WEDNESDAY.
WINDS ARE EXPECTED TO BE SOUTHWEST AT 10 TO 20 MPH WITH GUSTS UP
TO 30 MPH TONIGHT...WEST TO NORTHWEST AT 10 TO 20 MPH WITH GUSTS
UP TO 35 MPH ON TUESDAY DIMINISHING TO 5 TO 10 MPH AFTER MIDNIGHT
TUESDAY NIGHT...AND LIGHT AND VARIABLE AT 5 MPH OR LESS ON WEDNESDAY.
&&
.HYDROLOGY...
LITTLE PRECIPITATION IS EXPECTED DURING THE NEXT 5 DAYS. FORECAST
PRECIPITATION THROUGH SATURDAY MORNING RANGES FROM NEAR ZERO OVER
THE SOUTHEAST PART OF THE AREA TO AROUND THREE QUARTERS OF AN INCH
OVER THE NORTHWEST PART OF THE AREA. A LARGE LOW PRESSURE SYSTEM
COULD BRING A SOAKING RAIN THE REGION LATER SATURDAY THROUGH SUNDAY.
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.
&&
.CLIMATE...
RECORD HIGH TEMPERATURE WAS SET AT THE ALBANY INTERNATIONAL
AIRPORT WHEN IT REACHED 91 DEGREES AT 440 PM EDT. THIS BREAKS THE
PREVIOUS RECORD OF 89 DEGREES SET IN 2002 AND ALSO MARKS EARLIEST
90 DEGREE TEMPERATURE FOR ALBANY. PREVIOUSLY THE EARLIEST 90
DEGREE TEMPERATURE READING WAS APRIL 17TH OF 2002 WHEN THE
TEMPERATURE REACHED 91 DEGREES.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY
EVENING FOR CTZ001-013.
NY...FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY
EVENING FOR NYZ039>041-047>054-058>061-063>066-082.
MA...FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY
EVENING FOR MAZ001-025.
VT...NONE.
&&
$$
SYNOPSIS...11/WASULA
NEAR TERM...WASULA
SHORT TERM...11
LONG TERM...WASULA
AVIATION...11
FIRE WEATHER...11/WASULA
HYDROLOGY...SND
CLIMATE...11
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1253 PM EDT SUN APR 15 2012
.SYNOPSIS...
HIGH PRESSURE CENTERED OFF THE SOUTHEAST COAST WILL INFLUENCE OUR
REGION THROUGH MONDAY. A COLD FRONT FROM THE NORTHWEST IS FORECAST
TO CROSS THE REGION MONDAY NIGHT. HIGH PRESSURE WILL THEN BUILD
BACK IN FOR TUESDAY THROUGH THURSDAY. ANOTHER COLD FRONT IS
ANTICIPATED TO ARRIVE ON THURSDAY NIGHT OR FRIDAY. A STRONGER
STORM MAY IMPACT THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WITH THE EARLY AFTERNOON UPDATE, HOURLY TEMPERATURES WERE ADJUSTED
DOWN A FEW DEGREES ACROSS OUR CENTRAL TO NORTHERN ZONES WHERE MID-
LEVEL CLOUDS HAD REMAINED THICKER. WITH MORE BREAKS AND THE CLOUDS
THINNING OVER THESE AREAS EARLY THIS AFTERNOON, FCST MAX
TEMPERATURES STILL LOOK TO BE ON TRACK. MEANWHILE, GRADUAL CLEARING
HAD OCCURRED EARLIER ACROSS OUR DELMARVA ZONES, AND LITTLE
ADJUSTMENT WAS NEEDED FOR TEMPS. WE HAVE KEPT ISOLATED SHOWERS IN
THE FORECAST OVER THE NEXT SEVERAL HOURS FOR OUR FAR NORTHWEST
ZONES, AS THE HRRR APPEARED TO HAVE A GOOD REPRESENTATION OF THE
CURRENT ACTIVITY MOVING EASTWARD ALONG THE PA/NY BORDER.
OTHERWISE, VERY WEAK IMPULSES AT MID LEVEL LOOK LIKE THEY WILL BE
FIGHTING A LOSING BATTLE FROM SOUTH TO NORTH AGAINST THE BUILDING
RIDGE WITH THE AXIS TO OUR WEST TODAY. SHOWER ACTIVITY HAD GONE TO
THE ISOLATED LEVEL THIS MORNING, AND BY THIS AFTERNOON WE STILL
EXPECT AT LEAST THE SOUTHERN ZONES TO BE CLEAR OF ANY RAINFALL.
SEVERAL DAYS AGO, THIS WARM FRONTAL PASSAGE WAS DEPICTED AS
PRODUCING SOME SIGNIFICANT RAIN, BUT THAT HAS NOT YET COME TO
FRUITION. BARRING SOME UNEXPECTED DEVELOPMENT OVER OUR NORTHERN
ZONES LATER TODAY, IT WON`T.
WARM ADVECTION CLOUDS ARE FORECAST TO LINGER OVER MOST OF OUR
REGION THIS MORNING WITH A DECREASE IN CLOUD COVER THIS AFTERNOON
AS THE MID LEVEL RIDGE CONTINUES TO BUILD OVERHEAD.
WITH MARGINAL INSTABILITY ACROSS OUR NORTHERN COUNTIES, WE HAVE
MENTIONED ISOLATED SHOWERS THERE INTO THE EARLY AFTERNOON HOURS.
DUE TO THE SOUTHWESTERLY FLOW AND INCREASING SUNSHINE THIS
AFTERNOON, TEMPERATURES SHOULD RISE WELL INTO THE 70S IN OUR
REGION WITH A FEW SPOTS IN OUR WESTERN AND SOUTHERN COUNTIES
POSSIBLY REACHING THE 80 DEGREE MARK. THE NAM AND ECMWF FORECASTS
FOR 925 MB TEMPERATURES AT 12Z TODAY BASICALLY VERIFIED, AND THEIR
CONSENSUS FORECAST GENERALLY SUPPORTS THE AFTERNOON MAXES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
THE MID LEVEL RIDGE AXIS IS FORECAST TO PASS OVERHEAD TONIGHT
WITH A MOSTLY CLEAR SKY ANTICIPATED ALONG WITH A LIGHT SOUTHWEST
TO SOUTH WIND.
TEMPERATURES TONIGHT WILL BE RATHER MILD WITH LOWS MAINLY FROM
THE MIDDLE 50S TO THE LOWER 60S.
WITH DEW POINT TEMPERATURES ON THE RISE, THERE MAY BE SOME FOG
DEVELOPING OVER OUR COASTAL WATERS TONIGHT.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
ERLY IN THE EXTENDD PD, HIGH PRESSURE WILL BE OVER THE REGION
WITH AN AREA OF LOW PRES NR THE GRTLKS WILL MOVG EWD INTO SRN
CANADA AND A CDFNT WILL MOVE THRU THE REGION MONDAY NIGHT. ATTM,
IT APPEARS THE CDFNT WILL COME THRU DRY OR MOSTLY DRY. HIGH
PRESSURE THEN BUILDS BACK IN FOR TUESDAY THRU THURSDAY. ANOTHER
AREA OF LOW PRESSURE WILL MOVE BY TO THE NORTH THURSDAY NIGHT OR
FRIDAY MORNING BRINGING ANOTHER WK CDFNT THRU, WITH ANOTHER CHANCE
OF SOME SHOWERS ON FRIDAY. THEN, IT LOOKS LIKE A MORE ORGANIZED
CHANCE OF RAIN, AS A STORM ORGANIZES ACRS THE LWR MS VLY FRIDAY
NIGHT AND MOVES TO THE NE THRU THE WEEKEND. THERE ARE STILL TIMING
AND STRENGTH DIFFS WRT THIS SYS AS CAN BE EXPECTED WITH THIS TIME
SCALE. HOWEVER, ATTM IT LOOKS LIKE IT COULD BE THE MOST
SIGNIFICANT RAIN EVENT WE HAVE SEEN IN QUITE SOME TIME.
WITH THE HIGH PRESSURE IN CONTROL FOR MONDAY TEMPS LOOK TO BE
20-25 DEGREES ABOVE NRML AND WILL GRADUALLY DECREASE THRU THE WEEK
BUT WILL REMAIN ABOVE NRML THRU THE PD.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
ISOLATED LIGHT SHOWERS THIS MORNING HAVE ONLY A SMALL CHANCE OF
AFFECTING ANY INDIVIDUAL TAF SITE IN A TRANSIENT MANNER. CEILING
AND VISIBILITY VALUES THEREFORE ARE FORECAST TO REMAIN IN THE VFR
RANGE. OVERCAST TO BROKEN CLOUDS ABOVE 3500 FEET RANGE SHOULD
BECOME SCATTERED FOR THIS AFTERNOON WITH SOME CIRRUS OVERHEAD.
THE SKY IS EXPECTED TO BECOME MOSTLY CLEAR FOR TONIGHT. HOWEVER,
A FOG BANK MAY DEVELOP OVER OUR COASTAL WATERS. IT COULD DRIFT
INLAND A BIT, POSSIBLY AFFECTING KACY AND KMIV LATE TONIGHT.
FORECAST CONFIDENCE IS LOW REGARDING THE FOG, SO IT HAS NOT BEEN
INCLUDED IN THE TAFS AT THIS TIME.
A SOUTHWEST WIND AROUND 4 TO 8 KNOTS IS FORECAST TO INCREASE INTO
THE 8 TO 12 KNOT RANGE THIS AFTERNOON WITH GUSTS AROUND 20 KNOTS
POSSIBLE. THE SOUTHWEST WIND SHOULD DECREASE BACK INTO THE 4 TO 8
KNOT RANGE FOR TONIGHT.
OUTLOOK...
MONDAY THRU THURSDAY...VFR WITH HIGH PRESSURE IN CONTROL. SOME
BRIEF SHOWERS CAN NOT BE RULED OUT MONDAY NIGHT WITH THE PASSAGE
OF A WEAK CDFNT.
&&
.MARINE...
WAVES AT BUOYS 44009 AND 44065 HAD DROPPED IN EXCESS OF ONE FOOT
BELOW THE ADVISORY CRITERION THIS MORNING, AND SO THE ADVISORY FOR
ROUGH SEAS WAS CANCELLED.
A SOUTHWEST TO SOUTH WIND AT AROUND 10 KNOTS WILL PICK UP A BIT
ALONG THE IMMEDIATE COASTLINE BUT NOT FURTHER OUT THIS AFTERNOON.
THE AIR WILL WARM AND RIDE OVER THE COOL WATER, LESSENING THE
MIXING OF THE BOUNDARY LAYER. WAVE HEIGHTS ARE FORECAST IN THE 2
TO 4 FEET RANGE FOR THIS AFTERNOON ON OUR OCEAN WATERS. WE WILL
CONTINUE TO MONITOR THE TRENDS IN THE EVENT THAT THE FLOW BECOMES
SUFFICIENTLY SOUTH OF OFFSHORE TO CAUSE ANOTHER RISE.
MEANWHILE WIND SPEEDS AND GUSTS ARE FORECAST TO REMAIN BELOW 25
KNOTS INTO MONDAY. THE DIRECTION WILL CONTINUE TO FAVOR THE SOUTH
AND SOUTHWEST.
WITH DEW POINT TEMPERATURES ON THE RISE, THERE MAY BE SOME FOG
DEVELOPING OVER OUR COASTAL WATERS TONIGHT.
OUTLOOK...
HIGH PRESSURE WILL BE IN CONTROL TO START THE PD AND WINDS AND
SEAS WILL REMAIN BELOW CRITERIA. A WK CDFNT WILL CROSS THE REGION
MONDAY NIGHT AND SOME GUIDANCE IS INDICATING THAT SCA CRITERIA
WILL BE REACHED AT THAT TIME. HIGH PRESSURE THEN BUILDS BACK IN
FOR THE BALANCE OF THE WEEK WITH WINDS AND SEAS REMAINING BELOW
SCA CRITERIA. BY THURSDAY NIGHT OR FRIDAY ANOTHER COLD FRONT WILL
APPROACH AND WE COULD BE LOOKING AT MARGINAL SCA CONDS AGAIN, BUT
THE BEST CHANCE FOR SCA CRITERIA LOOKS TO BE OVER THE WEEKEND WHEN
A STRONGER STORM WILL IMPACT THE COASTAL WATERS.
&&
.FIRE WEATHER...
FINE FUELS REMAIN DRY WITH THE LITTLE BIT OF RAIN THAT HAS
OCCURRED. WIND AND RELATIVE HUMIDITY CONDITIONS SHOULD NOT COMBINE
TO CREATE ENHANCED FIRE WEATHER CONCERNS FOR TODAY. HOWEVER,
CONDITIONS MAY GET CLOSE IN PARTS OF OUR REGION AGAIN ON MONDAY.
&&
.CLIMATE...
WITH A MUCH WARMER AIR MASS MAKING ITS WAY TO OUR REGION FOR
EARLY NEXT WEEK, THERE IS THE POTENTIAL FOR SOME OF THE REGIONS
RECORD HIGH TEMPERATURES TO BE APPROACHED.
HERE ARE THE RECORD HIGH TEMPERATURES FOR ALL EIGHT OF OUR
CLIMATE SITES FOR MONDAY.
ALLENTOWN 89 - 2002
ATLANTIC CITY 89 - 2002
GEORGETOWN 89 - 2002
MOUNT POCONO 85 - 2002
PHILADELPHIA 90 - 2002
READING 88 - 2002
TRENTON 90 - 2002
WILMINGTON 92 - 1896
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NIERENBERG
NEAR TERM...DELISI/IOVINO/KLINE
SHORT TERM...IOVINO
LONG TERM...NIERENBERG
AVIATION...DELISI/IOVINO/NIERENBERG
MARINE...DELISI/IOVINO/NIERENBERG
FIRE WEATHER...IOVINO
CLIMATE...MEOLA
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1002 PM EDT Mon Apr 16 2012
.UPDATE...
No major changes to the inherited forecast as it generally seems
on track. PoPs were slightly redistributed to be focused more in
our SE Alabama zones where shower and thunderstorm activity has
been most persistent. To the west of Dothan, PoPs were increased
into the 50-60% range to produce a small area of "numerous
showers" wording in the forecast in the evening. Isolated thunder
was included through 04z given recent lightning strikes, but as
instability wanes so should lightning activity in a few hours.
Previous gradient of low temperatures still looks good: warmest in
the NW where clouds will persist longer, and coolest in the SE
where clouds should not be an issue.
HYSPLIT runs using the RUC and NAM, as well as analysis of our
local WRF boundary layer winds suggests that any smoke from the
County Line Fire will be transported mainly north through 09z and
then eventually NNE-NE. There may be a bit of smoke that drifts
into our area near Valdosta, but visibility should not be a major
issue. Despite the consistency of the models, the I-75 corridor
will be monitored closely for visibility trends overnight.
&&
.PREV DISCUSSION (issued at 732 PM EDT Mon Apr 16 2012)...
SYNOPSIS... Surface analysis shows a cold front starting at a low
between Wisconsin and Michigan, extending down through Texas.
Ahead of this cold front, especially in the southeast, severe
storms have already developed. Local radar imagery shows some
thunderstorms have developed over Mobile`s watch area as well,
although the severe cells remain to the west, over Texas,
Louisiana, and into Mississippi.
NEAR TERM (Rest of today and tonight)... The aforementioned
storms are not expected to reach our area until later tomorrow,
however the western portion of our warning area may see some
showers this afternoon and evening ahead of the front. Highs today
should be in the mid to upper 80s, with temperatures higher to the
east where rain is unlikely and the possibility of highs not
reaching their full potential with rain onset to the west. Highs
will also be lower near the coast. Lows tonight will be in the
lower 60s overnight.
SHORT TERM (Tuesday through Wednesday night)... High resolution
and global guidance both agree that the main shortwave trough
responsible for the approaching weather will not affect our local
area until Tuesday evening. There will be the possibility for a
few showers during the afternoon on Tuesday as a low-level vort
max rotates north out of the Gulf across north Florida, and
eventually into Georgia and Alabama. The NAM, and the full suite
of high resolution guidance both support this. Showers and
isolated thunderstorms with the shortwave will approach our
Alabama and Florida panhandle counties by Tuesday evening and
won`t clear our SE Big Bend counties until Wednesday evening.
The threat for severe weather with both waves of showers
and thunderstorms is low. Although instability will exist each
afternoon, and lapse rates are more favorable than recent events,
the low-level and deep layer shear appear too weak to support
organized updrafts. This is supported in full by near nil severe
probabilities generated locally by both high resolution and
global guidance. There will certainly be some thunderstorms
around, and the main threat with the strongest of these storms
will be gusty winds and small hail (both below severe thresholds).
With the shortwave trough holding position to our west on Tuesday,
highs will still be able to reach the middle 80s for most
locations. Lower 80s are likely along the coast and across our
westernmost Florida and Alabama counties. Tuesday night, lower 60s
will be common area wide. On Wednesday, more rain coupled with
slightly lower heights will yield temperatures in the upper 70s to
lower 80s.
LONG TERM (Thursday through next Monday)... Both the GFS and
ECMWF are in general agreement to commence the period. This shows
a rather deamplified large scale longwave pattern highlighted by
weak troughing over Wrn states and very broad ridging over Ern
states. At surface, the quasi-stnry front responsible for
Wednesday`s weather has exited just south of local area with high
pressure beginning to ridge in from the ENE with some residual
moisture lingering showers especially ern third of CWA.
Both models now in better agreement in evolution of upstream trough
as it begins to dig into the mid south by weekend, however EURO
more amplified by time it arrives across NE Gulf on Sat. Ahead of
system, next upper shortwave begins to dig into MS Valley on Fri
with a strong sly flow pattern setting up ahead. By eve, amplified
ridge over Wrn half and trough over Ern half with axis swd down MS
Valley and by Sat aftn axis from Great Lakes down thru NE Gulf.
Trough begins to lift newd beginning Sat night with upstream ridge
beginning to impact Ern states with subsidence, rising heights and
NW steering flow overspreading region into Mon. At surface, by Fri
morning, low over TX/OK panhandle with cold front across TX. By Fri
eve, low lifts to Nrn TN Valley with front SSW across Ern MS. Low
lifts newd to mid-Atlc coast Sat aftn with strong cold front moving
across local region. It looks like a squall line will be developing
ahead of the front. New 00z guidance shows ECMWF with low developing
on front over forecast area at 18z Sat before lifting into Carolinas
by 12z Sun. GFS with weaker low across GA/SC border at that time. If
all falls into place (and especially if EURO verifies) strong to
severe storms a good bet. By sat eve, front exits ewd of local area
with drier and cooler air building in its wake thru rest of the
period. Expect breezy offshore winds and hazardous marine conditions
Sun into Mon.
Will go with nil pops except for mid sct pops sat aftn and wdly sct-
low sct pops sat morning and night as well as Wed night. With local
area remaining in the warm sector, min/max temps will be around 5
degrees above climo wed, night thru Fri night dropping around climo
sat and sat night and 5 degrees below normal sun then 5 to 10
degrees below climo sun night and Mon in the wake of the front if
GFS verifies, and downright cold, in excess of 10 degrees if EURO
verifies. (avg inland min/max climo is 54/81 degrees).
AVIATION (through 00Z Wednesday)... Scattered showers and
isolated TS in the vicinity of DHN should dissipate by 01-02Z.
Brief MVFR vsby restrictions will be possible at all terminals for
a few hours around sunrise. Our confidence is highest at VLD which
will once again be impacted by smoke from the east. In an attempt
to keep the Columbia Line fire from flaring once again, a planned
burnout operation occurred for a few hours this afternoon. This
has once again generated a modest amount of smoke and dispersion
models show this drifting northwest to the VLD vicinity overnight.
For now, we hold the vsby at the low end of MVFR, but IFR
conditions will certainly be possible. Looking ahead to the
daytime hours Tuesday, it appears that a broken VFR ceiling around
6-7 kft will prevail throughout the day. Any convection that fires
before 00Z should be limited to the DHN area once again and we
indicated a small chance for TS at that terminal.
MARINE... Light winds and seas will continue through the rest of
the week as the majority of the surface based pressure systems
remain north of our coastal waters. However, there will be a
chance for rain throughout at least the middle of the work week.
FIRE WEATHER... A frontal system will likely move through our
region tomorrow through Wednesday. Thursday and Friday will be
drier in terms of weather, but relative humidity values will
remain higher with the approach of another frontal system which
should reach our area on Saturday. These fronts will bring some
needed moisture to the region and keep the relative humidity
values above critical values until around Sunday when the dry air
mass behind the second cold front will begin to dominate.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 59 85 62 81 59 / 10 20 30 50 20
Panama City 65 80 65 79 62 / 10 20 50 50 10
Dothan 63 83 60 80 55 / 40 30 60 40 10
Albany 62 84 62 79 56 / 20 20 50 60 20
Valdosta 59 85 62 81 57 / 10 20 20 40 30
Cross City 57 84 60 81 59 / 10 10 20 50 30
Apalachicola 64 79 66 77 63 / 10 10 40 50 20
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
Update...Lamers
Aviation...Wool
Short Term...Harrigan
Marine...Harrigan
Rest of Discussion...Moore
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
511 PM CDT SUN APR 15 2012
.MESOSCALE DISCUSSION...
235 PM CDT
THE 18Z SOUNDINGS FROM DVN AND ILX BOTH SHOW A MUCH MORE STOUT
CAPPING INVERSION PRESENT THAN HAD BEEN FORECAST BY THE VARIOUS
MODELS. DESPITE FAIRLY EXTENSIVE AND IN SOME CASES DENSE
CIRRUS...SFC TEMPS CONTINUE TO WARM WHICH IS HELPING WEAKEN THE
BOUNDARY LAYER CONVECTIVE INHIBITION SOMEWHAT...THOUGH SERIES OF
ACARS SOUNDINGS OUT OF MDW SHOW EVIDENCE OF INCREASING MID LEVEL
SUBSIDENCE...LIKELY IN THE WAKE OF THE LEAD WAVE THAT PASSED BY THIS
MORNING.
SOME MOISTENING/COOLING HAS BEEN NOTED ON WATER VAPOR IMAGERY OVER
SOUTHERN MISSOURI LIKELY IN ASSOCIATION WITH INCREASING ASCENT WITH
APPROACHING MID/UPPER LEVEL JET ROUNDING THE BASE OF THE TROUGH.
GIVEN THE CAPPING IN PLACE SUSPECT THAT MORE THE ROBUST/WIDESPREAD
CONVECTION IN OUR AREA MAY END UP WAITING UNTIL THE ARRIVAL OF THIS
FORCING LATE THIS AFTERNOON INTO THIS EVENING. FORECAST SOUNDINGS
FROM THE RUC DO SUGGEST THAT THIS WILL OCCUR...SO THE THREAT STILL
IS THERE FOR SEVERE WEATHER IS STILL THIS EVENING.
ASSUMING MORE INTENSE CONVECTION DOES INDEED GET GOING IN THE AREA
THIS EVENING...ITS LOOKING MORE LIKELY THAT IT WILL BE A VERY HIGH
SHEAR/LOW CAPE TYPE ENVIRONMENT WITH MAINLY A DAMAGING WIND THREAT.
THOUGH AS ALLUDED TO IN THE PREVIOUS MESO-AFD...THE EXTREME SHEAR
DOES CERTAINLY RAISE CONCERNS ABOUT THE TORNADO POTENTIAL DESPITE
THE EXPECTED LIMITED INSTABILITY.
IZZI
&&
.DISCUSSION...
300 PM CDT
THE REMAINDER OF THE SHORT TERM...MONDAY THROUGH WEDNESDAY...
CONDITIONS WILL QUIET DOWN CONSIDERABLE FOLLOWING THE PASSAGE OF
THE COLD FRONT MONDAY MORNING. THERE IS A CHANCE FOR SOME WRAP
AROUND SHOWERS OVER THE NRN PORTIONS OF THE CWA MONDAY AFTERNOON
AS THE LOW PRESSURE SYSTEM EXITS TO THE NORTHEAST...BUT ANY PCPN
WOULD LIKELY BE ONLY SOME LIGHT RAIN SHOWERS. STRONG COLD
ADVECTION WILL SET UP FOLLOWING THE FROPA...SO THERE SHOULD BE
LITTLE DIURNAL WARMING THROUGH THE DAY WITH TEMPERATURES REMAINING
STEADY IN THE MIDDLE 50S TO LOWER 60S THROUGH THE DAY. THROUGH THE
EVENING AND INTO THE OVERNIGHT HOURS...COOL HIGH PRESSURE WILL
BUILD OUT OF THE PLAINS AND INTO THE AREA...WITH THE HIGH PRESSURE
SPREADING INTO THE OHIO VALLEY BY TUESDAY MORNING. CLEARING SKIES
AND DECREASING WINDS...COINCIDENT WITH SHARPLY LOWER DEWPOINTS
WILL SET UP A SCENARIO FOR STRONG RADIATIVE COOLING...WITH MUCH OF
THE CWA NORTH OF THE ILLINOIS/KANKAKEE RIVER VALLEYS SEEING
TEMPERATURES DROPPING TO AS LOW AS 34-35 DEGREES. THIS SHOULD
ALLOW FOR AT LEAST PATCHY FROST TO FORM DURING THE EARLY MORNING
HOURS. AT THIS POINT...DO NOT SEE TEMPERATURES DROPPING INTO THE
LOWER 30S...SO A FREEZE IS NOT EXPECTED. THE URBANIZED AREAS OF
THE CHICAGO METRO AREA AND LOCATIONS INVOF LAKE MICHIGAN SHOULD
REMAIN A BIT WARMER WITH TEMPERATURES REMAINING IN THE UPPER 30S
TO ARND 40F...SO NO FROST IS LIKELY THERE. THE REMAINDER OF
TUESDAY SHOULD BE DRY WITH NELY WINDS SETTING UP AS THE HIGH
PASSES OFF TO THE EAST. THE ONSHORE FLOW OFF OF LAKE MICHIGAN WILL
KEEP LAKEFRONT LOCATIONS RATHER COOL...WITH HIGHS ONLY IN THE
UPPER 40S TO LOWER 50S...BUT AMPLE SUNSHINE WILL ALLOW THE
REMAINDER OF THE AREA TO WARM UP INTO THE UPPER 50S TO LOWER 60S.
TUESDAY NIGHT AND INTO WEDNESDAY SHOULD SEE A RETURN TO MORE
SOUTHERLY FLOW AS THE HIGH CONTINUES EWD AND THE NEXT UPSTREAM
SYSTEM DROPS OUT OF THE NRN ROCKIES AND TRACKS ACROSS THE NRN PLAINS
TO THE UPPER GREAT LAKES. THE LATEST GFS/ECMWF ARE IN QUITE GOOD
AGREEMENT ON HANDLING THIS SYSTEM AND ARE TRENDING A LITTLE SLOWER
THAN THE NAM SOLUTION. FOR THE END OF THE SHORT TERM FORECAST
PERIOD AND INTO THE LONG TERM PERIOD...FROM WEDNESDAY AND THROUGH
THE WEEKEND...HAVE GENERALLY FOLLOWED FAIRLY CLOSELY TO THE
GFS/ECMWF PATTERN. THIS SOLUTIONS BRINGS THE NEXT SIGNIFICANT
CHANCE OF PCPN TO THE AREA WEDNESDAY AFTERNOON AND EVENING. THIS
RESPONSIBLE SYSTEM WILL BE A NRN STREAM SYSTEM...ALMOST
CLIPPER-LIKE...TRACKING THROUGH THE UPPER MISSISSIPPI VALLEY AND
UPPER GREAT LAKES REGIONS. A TRAILING WEAK COLD FRONT SHOULD SWEEP
THROUGH THE CWA LATE WEDNESDAY AFTERNOON...BRINGING SHOWERS AND
PERHAPS A CHANCE FOR A FEW THUNDERSTORMS...BUT THIS SYSTEM WILL BE
RATHER QUICK-MOVING SO THE WINDOW OF OPPORTUNITY FOR THUNDER WILL BE
FAIRLY SHORT...AND THERE SHOULD BE LITTLE OR NO POTENTIAL FOR ANY
SEVERE WEATHER WITH THIS SYSTEM. THERE MAY BE ANOTHER CHANCE FOR
SOME RAIN OVER THE AREA BY THURSDAY NIGHT OR FRIDAY AS A SOUTHERN
STREAM SYSTEM LIFTS OUT OF THE SRN PLAINS. THE MODELS ARE SHOWING A
BIT MORE OF A SPREAD IN THE TRACK OF THIS SYSTEM WITH THE ECMWF
ADVERTISING A FASTER...MORE NORTHERLY TRACK THROUGH NRN
IL/IN/OH...WHILE THE GFS IS A BIT INDICATES A SLOWER...MORE
SOUTHERLY TRACK THROUGH THE OHIO VALLEY. A QUICK LOOK AT THE GEM
SPLITS THE DIFFERENCE BETWEEN THE GFS/ECMWF TRACKS...SO THE PATH OF
LEAST RESISTANCE AT THIS POINT HAS BEEN TO GO WITH THE MORE MIDDLE
OF THE ROAD APPROACH. ANY OF THESE SCENARIOS WOULD BRING SOME RAIN
TO THE CWA...BUT ANY THUNDERSTORM POTENTIAL WOULD BE MORE DIRECTLY
IMPACTED BY THE EXACT PATH OF THE SYSTEM. SO HAVE INDICATED A
SLIGHT CHANCE FOR SOME THUNDER ON THURSDAY...BUT CONFIDENCE IS NOT
VERY HIGH ON THIS POTENTIAL.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* BRIEF PERIOD OF SHOWERS AND MAYBE A RUMBLE OF THUNDER AROUND 23
UTC AT KMDW AS SOME SHOWERS QUICKLY MOVE ACROSS THE AREA.
* ADDITIONAL TSRA MOVING THROUGH THE TERMINALS THIS EVENING.
PERIODS OF HEAVY RAIN...HAIL...FREQUENT LIGHTNING...AND BRIEF
IFR VIS POSSIBLE.
* STRONG SOUTH WINDS GUSTING TO 30-35 KT INTO THE EVENING...NOT
ASSOCIATED WITH THUNDERSTORMS.
IZZI/KB
//DISCUSSION...UPDATED 18Z...
STRONG LOW PRESSURE CENTER MOVING INTO MINNESOTA BY THIS EVENING
WILL SUPPORT REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS BY THIS
EVENING. THE MOST FAVORABLE AREA FOR REDEVELOPMENT IS TO THE WEST
OF THE TERMINALS...AND THEN MOVING EAST THROUGH THE EVENING. LOW
LEVEL SOUTH-SOUTHWEST WINDS ASSOCIATED WITH THE LOW WILL GUST INTO
THE 30-35 KT RANGE AT TIMES DURING THE AFTERNOON AND EVENING.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM CONFIDENCE ON TIMING TS MOVING THROUGH THIS EVENING.
* MEDIUM TO HIGH CONFIDENCE ON WIND TRENDS.
IZZI/KB
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...
TUESDAY...VFR.
WEDNESDAY...VFR. CHC MVFR CIGS W/SHRA ISO TSRA
MIDDAY/AFTN.
THURSDAY...VFR. CHC SHRA.
FRIDAY...VFR. CHC SHRA ISO TSRA.
SATURDAY...VFR. CHC SHRA.
LENNING
&&
.MARINE...
257 PM...STRONG LOW PRESSURE ACROSS THE PLAINS THIS AFTERNOON WILL
MOVE NORTHEAST ACROSS THE NORTHERN LAKES MONDAY MORNING AND INTO
QUEBEC MONDAY NIGHT. AS THIS LOW APPROACHES...A WARM FRONT CURRENTLY
OVER NORTHERN LAKE MICHIGAN WILL LIFT NORTH OF THE LAKE...WITH
SOUTHEAST WINDS TURNING MORE SOUTHERLY. DENSE FOG ALONG AND AHEAD
OF THIS FRONT SHOULD IMPROVE ONCE WINDS TURN SOUTHERLY.
WHILE THE GRADIENT WILL CONTINUE TO TIGHTEN AS THE LOW APPROACHES...
A VERY STABLE MARINE LAYER SHOULD PREVENT WINDS FROM INCREASING MUCH
ABOVE 30 KTS OVER THE OPEN WATERS...PERHAPS A FEW HIGHER GUSTS AT
TIMES. OFFSHORE FLOW FROM DEEPER MIXING OVER LAND WILL STILL SUPPORT
FREQUENT GALES IN THE ILLINOIS AND INDIANA NEARSHORE WATERS AND HAVE
EXTENDED THE GALE WARNING FOR THE ILLINOIS/INDIANA NEARSHORE WATERS
THROUGH MONDAY AFTERNOON. AND AT THIS TIME...HAVE MAINTAINED THE
GALE WATCH FOR THE OPEN WATERS. WHILE GALES STILL LOOK POSSIBLE OVER
THE NORTHERN PART OF THE LAKE LATE MONDAY AFTERNOON INTO MONDAY
EVENING...BY THE TIME THE MARINE LAYER WEAKENS DUE TO COLDER AIR
ARRIVING...THE WINDS ALOFT ARE 30 KTS OR LESS. THE POTENTIAL FOR
GALE FORCE WINDS STILL EXISTS...BUT CONFIDENCE IS FAIRLY LOW OVER
SOUTHERN LAKE MICHIGAN. WINDS SHOULD DIMINISH QUICKLY MONDAY
NIGHT INTO TUESDAY MORNING AS HIGH PRESSURE BECOMES CENTERED OVER
THE LAKE BY MIDDAY TUESDAY...WITH LAKE BREEZES LIKELY ALONG ALL OF
THE SHORES OF LAKE MICHIGAN. THIS HIGH QUICKLY MOVES EAST TUESDAY
NIGHT WITH LOW PRESSURE LIFTING NORTHEAST ACROSS THE UPPER MIDWEST
AND EVENTUALLY THE NORTHERN LAKES ON WEDNESDAY...WHICH WILL
TIGHTEN A SOUTHERLY GRADIENT WITH WINDS TO 30 KTS POSSIBLE. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 1 AM MONDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 1 AM
MONDAY.
LM...GALE WATCH...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...10 AM MONDAY TO 9 PM
MONDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 7 PM
SUNDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...3 PM MONDAY TO 1 AM TUESDAY.
GALE WARNING...NEARSHORE WATERS UNTIL 7
PM MONDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
303 PM CDT SUN APR 15 2012
.MESOSCALE DISCUSSION...
235 PM CDT
THE 18Z SOUNDINGS FROM DVN AND ILX BOTH SHOW A MUCH MORE STOUT
CAPPING INVERSION PRESENT THAN HAD BEEN FORECAST BY THE VARIOUS
MODELS. DESPITE FAIRLY EXTENSIVE AND IN SOME CASES DENSE
CIRRUS...SFC TEMPS CONTINUE TO WARM WHICH IS HELPING WEAKEN THE
BOUNDARY LAYER CONVECTIVE INHIBITION SOMEWHAT...THOUGH SERIES OF
ACARS SOUNDINGS OUT OF MDW SHOW EVIDENCE OF INCREASING MID LEVEL
SUBSIDENCE...LIKELY IN THE WAKE OF THE LEAD WAVE THAT PASSED BY THIS
MORNING.
SOME MOISTENING/COOLING HAS BEEN NOTED ON WATER VAPOR IMAGERY OVER
SOUTHERN MISSOURI LIKELY IN ASSOCIATION WITH INCREASING ASCENT WITH
APPROACHING MID/UPPER LEVEL JET ROUNDING THE BASE OF THE TROUGH.
GIVEN THE CAPPING IN PLACE SUSPECT THAT MORE THE ROBUST/WIDESPREAD
CONVECTION IN OUR AREA MAY END UP WAITING UNTIL THE ARRIVAL OF THIS
FORCING LATE THIS AFTERNOON INTO THIS EVENING. FORECAST SOUNDINGS
FROM THE RUC DO SUGGEST THAT THIS WILL OCCUR...SO THE THREAT STILL
IS THERE FOR SEVERE WEATHER IS STILL THIS EVENING.
ASSUMING MORE INTENSE CONVECTION DOES INDEED GET GOING IN THE AREA
THIS EVENING...ITS LOOKING MORE LIKELY THAT IT WILL BE A VERY HIGH
SHEAR/LOW CAPE TYPE ENVIRONMENT WITH MAINLY A DAMAGING WIND THREAT.
THOUGH AS ALLUDED TO IN THE PREVIOUS MESO-AFD...THE EXTREME SHEAR
DOES CERTAINLY RAISE CONCERNS ABOUT THE TORNADO POTENTIAL DESPITE
THE EXPECTED LIMITED INSTABILITY.
IZZI
&&
.DISCUSSION...
300 PM CDT
THE REMAINDER OF THE SHORT TERM...MONDAY THROUGH WEDNESDAY...
CONDITIONS WILL QUIET DOWN CONSIDERABLE FOLLOWING THE PASSAGE OF
THE COLD FRONT MONDAY MORNING. THERE IS A CHANCE FOR SOME WRAP
AROUND SHOWERS OVER THE NRN PORTIONS OF THE CWA MONDAY AFTERNOON
AS THE LOW PRESSURE SYSTEM EXITS TO THE NORTHEAST...BUT ANY PCPN
WOULD LIKELY BE ONLY SOME LIGHT RAIN SHOWERS. STRONG COLD
ADVECTION WILL SET UP FOLLOWING THE FROPA...SO THERE SHOULD BE
LITTLE DIURNAL WARMING THROUGH THE DAY WITH TEMPERATURES REMAINING
STEADY IN THE MIDDLE 50S TO LOWER 60S THROUGH THE DAY. THROUGH THE
EVENING AND INTO THE OVERNIGHT HOURS...COOL HIGH PRESSURE WILL
BUILD OUT OF THE PLAINS AND INTO THE AREA...WITH THE HIGH PRESSURE
SPREADING INTO THE OHIO VALLEY BY TUESDAY MORNING. CLEARING SKIES
AND DECREASING WINDS...COINCIDENT WITH SHARPLY LOWER DEWPOINTS
WILL SET UP A SCENARIO FOR STRONG RADIATIVE COOLING...WITH MUCH OF
THE CWA NORTH OF THE ILLINOIS/KANKAKEE RIVER VALLEYS SEEING
TEMPERATURES DROPPING TO AS LOW AS 34-35 DEGREES. THIS SHOULD
ALLOW FOR AT LEAST PATCHY FROST TO FORM DURING THE EARLY MORNING
HOURS. AT THIS POINT...DO NOT SEE TEMPERATURES DROPPING INTO THE
LOWER 30S...SO A FREEZE IS NOT EXPECTED. THE URBANIZED AREAS OF
THE CHICAGO METRO AREA AND LOCATIONS INVOF LAKE MICHIGAN SHOULD
REMAIN A BIT WARMER WITH TEMPERATURES REMAINING IN THE UPPER 30S
TO ARND 40F...SO NO FROST IS LIKELY THERE. THE REMAINDER OF
TUESDAY SHOULD BE DRY WITH NELY WINDS SETTING UP AS THE HIGH
PASSES OFF TO THE EAST. THE ONSHORE FLOW OFF OF LAKE MICHIGAN WILL
KEEP LAKEFRONT LOCATIONS RATHER COOL...WITH HIGHS ONLY IN THE
UPPER 40S TO LOWER 50S...BUT AMPLE SUNSHINE WILL ALLOW THE
REMAINDER OF THE AREA TO WARM UP INTO THE UPPER 50S TO LOWER 60S.
TUESDAY NIGHT AND INTO WEDNESDAY SHOULD SEE A RETURN TO MORE
SOUTHERLY FLOW AS THE HIGH CONTINUES EWD AND THE NEXT UPSTREAM
SYSTEM DROPS OUT OF THE NRN ROCKIES AND TRACKS ACROSS THE NRN PLAINS
TO THE UPPER GREAT LAKES. THE LATEST GFS/ECMWF ARE IN QUITE GOOD
AGREEMENT ON HANDLING THIS SYSTEM AND ARE TRENDING A LITTLE SLOWER
THAN THE NAM SOLUTION. FOR THE END OF THE SHORT TERM FORECAST
PERIOD AND INTO THE LONG TERM PERIOD...FROM WEDNESDAY AND THROUGH
THE WEEKEND...HAVE GENERALLY FOLLOWED FAIRLY CLOSELY TO THE
GFS/ECMWF PATTERN. THIS SOLUTIONS BRINGS THE NEXT SIGNIFICANT
CHANCE OF PCPN TO THE AREA WEDNESDAY AFTERNOON AND EVENING. THIS
RESPONSIBLE SYSTEM WILL BE A NRN STREAM SYSTEM...ALMOST
CLIPPER-LIKE...TRACKING THROUGH THE UPPER MISSISSIPPI VALLEY AND
UPPER GREAT LAKES REGIONS. A TRAILING WEAK COLD FRONT SHOULD SWEEP
THROUGH THE CWA LATE WEDNESDAY AFTERNOON...BRINGING SHOWERS AND
PERHAPS A CHANCE FOR A FEW THUNDERSTORMS...BUT THIS SYSTEM WILL BE
RATHER QUICK-MOVING SO THE WINDOW OF OPPORTUNITY FOR THUNDER WILL BE
FAIRLY SHORT...AND THERE SHOULD BE LITTLE OR NO POTENTIAL FOR ANY
SEVERE WEATHER WITH THIS SYSTEM. THERE MAY BE ANOTHER CHANCE FOR
SOME RAIN OVER THE AREA BY THURSDAY NIGHT OR FRIDAY AS A SOUTHERN
STREAM SYSTEM LIFTS OUT OF THE SRN PLAINS. THE MODELS ARE SHOWING A
BIT MORE OF A SPREAD IN THE TRACK OF THIS SYSTEM WITH THE ECMWF
ADVERTISING A FASTER...MORE NORTHERLY TRACK THROUGH NRN
IL/IN/OH...WHILE THE GFS IS A BIT INDICATES A SLOWER...MORE
SOUTHERLY TRACK THROUGH THE OHIO VALLEY. A QUICK LOOK AT THE GEM
SPLITS THE DIFFERENCE BETWEEN THE GFS/ECMWF TRACKS...SO THE PATH OF
LEAST RESISTANCE AT THIS POINT HAS BEEN TO GO WITH THE MORE MIDDLE
OF THE ROAD APPROACH. ANY OF THESE SCENARIOS WOULD BRING SOME RAIN
TO THE CWA...BUT ANY THUNDERSTORM POTENTIAL WOULD BE MORE DIRECTLY
IMPACTED BY THE EXACT PATH OF THE SYSTEM. SO HAVE INDICATED A
SLIGHT CHANCE FOR SOME THUNDER ON THURSDAY...BUT CONFIDENCE IS NOT
VERY HIGH ON THIS POTENTIAL.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* TSRA MOVING THROUGH THE TERMINALS THIS EVENING. PERIODS OF HEAVY
RAIN...HAIL...FREQUENT LIGHTNING...AND BRIEF IFR VIS POSSIBLE.
* STRONG SOUTH-SOUTHWEST WINDS GUSTING TO 30-35 KT THROUGH THE DAY
AND INTO THE EVENING...NOT ASSOCIATED WITH THUNDERSTORMS.
IZZI
//DISCUSSION...UPDATED 18Z...
STRONG LOW PRESSURE CENTER MOVING INTO MINNESTOA BY THIS EVENING
WILL SUPPORT REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS BY THIS
EVENING. THE MOST FAVORABLE AREA FOR REDEVELOPMENT IS TO THE WEST
OF THE TERMINALS...AND THEN MOVING EAST THROUGH THE EVENING. LOW
LEVEL SOUTH-SOUTHWEST WINDS ASSOCIATED WITH THE LOW WILL GUST INTO
THE 30-35 KT RANGE AT TIMES DURING THE AFTERNOON AND EVENING.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN NO PRECIPITATION THROUGH THE AFTERNOON.
* MEDIUM CONFIDENCE ON TIMING TS MOVING THROUGH THIS EVENING.
* MEDIUM TO HIGH CONFIDENCE ON WIND TRENDS.
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...
TUESDAY...VFR.
WEDNESDAY...VFR. CHC MVFR CIGS W/SHRA ISO TSRA
MIDDAY/AFTN.
THURSDAY...VFR. CHC SHRA.
FRIDAY...VFR. CHC SHRA ISO TSRA.
SATURDAY...VFR. CHC SHRA.
LENNING
&&
.MARINE...
257 PM...STRONG LOW PRESSURE ACROSS THE PLAINS THIS AFTERNOON WILL
MOVE NORTHEAST ACROSS THE NORTHERN LAKES MONDAY MORNING AND INTO
QUEBEC MONDAY NIGHT. AS THIS LOW APPROACHES...A WARM FRONT CURRENTLY
OVER NORTHERN LAKE MICHIGAN WILL LIFT NORTH OF THE LAKE...WITH
SOUTHEAST WINDS TURNING MORE SOUTHERLY. DENSE FOG ALONG AND AHEAD
OF THIS FRONT SHOULD IMPROVE ONCE WINDS TURN SOUTHERLY.
WHILE THE GRADIENT WILL CONTINUE TO TIGHTEN AS THE LOW APPROACHES...
A VERY STABLE MARINE LAYER SHOULD PREVENT WINDS FROM INCREASING MUCH
ABOVE 30 KTS OVER THE OPEN WATERS...PERHAPS A FEW HIGHER GUSTS AT
TIMES. OFFSHORE FLOW FROM DEEPER MIXING OVER LAND WILL STILL SUPPORT
FREQUENT GALES IN THE ILLINOIS AND INDIANA NEARSHORE WATERS AND HAVE
EXTENDED THE GALE WARNING FOR THE ILLINOIS/INDIANA NEARSHORE WATERS
THROUGH MONDAY AFTERNOON. AND AT THIS TIME...HAVE MAINTAINED THE
GALE WATCH FOR THE OPEN WATERS. WHILE GALES STILL LOOK POSSIBLE OVER
THE NORTHERN PART OF THE LAKE LATE MONDAY AFTERNOON INTO MONDAY
EVENING...BY THE TIME THE MARINE LAYER WEAKENS DUE TO COLDER AIR
ARRIVING...THE WINDS ALOFT ARE 30 KTS OR LESS. THE POTENTIAL FOR
GALE FORCE WINDS STILL EXISTS...BUT CONFIDENCE IS FAIRLY LOW OVER
SOUTHERN LAKE MICHIGAN. WINDS SHOULD DIMINISH QUICKLY MONDAY
NIGHT INTO TUESDAY MORNING AS HIGH PRESSURE BECOMES CENTERED OVER
THE LAKE BY MIDDAY TUESDAY...WITH LAKE BREEZES LIKELY ALONG ALL OF
THE SHORES OF LAKE MICHIGAN. THIS HIGH QUICKLY MOVES EAST TUESDAY
NIGHT WITH LOW PRESSURE LIFTING NORTHEAST ACROSS THE UPPER MIDWEST
AND EVENTUALLY THE NORTHERN LAKES ON WEDNESDAY...WHICH WILL
TIGHTEN A SOUTHERLY GRADIENT WITH WINDS TO 30 KTS POSSIBLE. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 1 AM MONDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 1 AM
MONDAY.
LM...GALE WATCH...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...10 AM MONDAY TO 9 PM
MONDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 7 PM
SUNDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...3 PM MONDAY TO 1 AM TUESDAY.
GALE WARNING...NEARSHORE WATERS UNTIL 7
PM MONDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
247 PM CDT SUN APR 15 2012
.MESOSCALE DISCUSSION...
235 PM CDT
THE 18Z SOUNDINGS FROM DVN AND ILX BOTH SHOW A MUCH MORE STOUT
CAPPING INVERSION PRESENT THAN HAD BEEN FORECAST BY THE VARIOUS
MODELS. DESPITE FAIRLY EXTENSIVE AND IN SOME CASES DENSE
CIRRUS...SFC TEMPS CONTINUE TO WARM WHICH IS HELPING WEAKEN THE
BOUNDARY LAYER CONVECTIVE INHIBITION SOMEWHAT...THOUGH SERIES OF
ACARS SOUNDINGS OUT OF MDW SHOW EVIDENCE OF INCREASING MID LEVEL
SUBSIDENCE...LIKELY IN THE WAKE OF THE LEAD WAVE THAT PASSED BY THIS
MORNING.
SOME MOISTENING/COOLING HAS BEEN NOTED ON WATER VAPOR IMAGERY OVER
SOUTHERN MISSOURI LIKELY IN ASSOCIATION WITH INCREASING ASCENT WITH
APPROACHING MID/UPPER LEVEL JET ROUNDING THE BASE OF THE TROUGH.
GIVEN THE CAPPING IN PLACE SUSPECT THAT MORE THE ROBUST/WIDESPREAD
CONVECTION IN OUR AREA MAY END UP WAITING UNTIL THE ARRIVAL OF THIS
FORCING LATE THIS AFTERNOON INTO THIS EVENING. FORECAST SOUNDINGS
FROM THE RUC DO SUGGEST THAT THIS WILL OCCUR...SO THE THREAT STILL
IS THERE FOR SEVERE WEATHER IS STILL THIS EVENING.
ASSUMING MORE INTENSE CONVECTION DOES INDEED GET GOING IN THE AREA
THIS EVENING...ITS LOOKING MORE LIKELY THAT IT WILL BE A VERY HIGH
SHEAR/LOW CAPE TYPE ENVIRONMENT WITH MAINLY A DAMAGING WIND THREAT.
THOUGH AS ALLUDED TO IN THE PREVIOUS MESO-AFD...THE EXTREME SHEAR
DOES CERTAINLY RAISE CONCERNS ABOUT THE TORNADO POTENTIAL DESPITE
THE EXPECTED LIMITED INSTABILITY.
IZZI
&&
.DISCUSSION...
1026 AM CDT
VERY DEEP //989MB// SFC LOW OVER CENTRAL NEBRASKA WILL CONTINUE TO
LIFT NORTHEAST TOWARD THE UPPER MISSISSIPPI VALLEY THROUGH
TONIGHT. PRESSURE GRADIENT AROUND THIS LOW HAS ALREADY RESULTED IN
WINDS GUSTING TO BETWEEN 30 AND 40 MPH THIS MORNING. WINDS SHOULD
CONTINUE TO INCREASE THIS AFTERNOON WITH SOME MIXED SUNSHINE AND
HEATING/MIXING...AND WHILE WE WILL SEE SOME DIURNAL SLACKENING OF
THE WINDS JUST OF THE DECK STILL THINK GUSTS OVER 40 MPH COULD
OCCUR THIS AFTERNOON. BY THIS EVENING SHOULD SEE WINDS JUST OFF
THE DECK RAPIDLY INCREASE TO 50-60KT 2000FT AGL AS EARLY AS 00Z
AND WITH STRONG PRESSURE FALLS/ISALOBARIC PUSH MAY SEE VERY LITTLE
DECOUPLING THIS EVENING WITH SURFACE WINDS PROBABLY INCREASING
EVEN FURTHER THIS EVENING. GIVEN THIS POTENTIAL HAVE OPTED TO
HOIST A WIND ADVISORY THROUGH 06Z FOR THE ENTIRE CWA.
WILL SHOOT TO HAVE A CONVECTIVE MESOSCALE AFD ISSUED PRIOR TO 17Z.
IZZI
//PREV DISCUSSION...
345 AM CDT
THE BULK OF THE OVERNIGHT SHOWER AND THUNDERSTORM ACTIVITY WILL BE
ON THE WANE AS WE APPROACH SUNRISE...WITH THE OVERALL ORIENTATION OF
THE REFLECTIVITY RETURNS TO SHIFT TO THE NORTHEAST AND EVENTUALLY
OUT OF THE CWA BY THE EARLY MORNING HOURS AS A SHORTWAVE SHOOTS OFF
TO MICHIGAN. HIGH RESOLUTION GUIDANCE HAD A DIFFICULT TIME DEALING
WITH SMALL SCALE FEATURES TONIGHT...AND NOTHING CAUGHT AN MCV
CHARGING EAST OUT OF KANSAS. IT WAS WITH THIS AREA THAT AN
IMPRESSIVE SQUALL WAS CHARGING THROUGH...PLOWING INTO IOWA AND
EVENTUALLY ACROSS OUR AREA. BY THE TIME IT HIT NORTH CENTRAL AND
NORTHEASTERN ILLINOIS...IT WEAKENED CONSIDERABLY AS THE ATMOSPHERE
WEST OF THE MISSISSIPPI WAS MUCH MORE PRIMED WHEN COMPARED TO
ACROSS THE CWA. HOWEVER...SPC ANALYSIS OF H8 MOISTURE TRANSPORT IS
INCREDIBLE AND WAS HELPING TO ADVECT IN HIGH PRECIPITABLE WATER
INTO THE AREA AND ALSO HELP TO PUSH SOME INSTABILITY ACROSS.
THE MAIN SURFACE LOW RESPONSIBLE FOR THE CURRENT WEATHER
SITUATION ACROSS THE PLAINS WILL LIFT NORTHEAST AND THROUGH
WISCONSIN BY THIS AFTERNOON. SOUTH OF THIS LOW IS A COLD FRONT
THAT WILL SWEEP ACROSS NORTHERN ILLINOIS AND NORTHWESTERN INDIANA
IN THE EVENING HOURS AND BRING THE NEXT CHANCES FOR SHOWERS AND
THUNDERSTORMS. THERE ARE A LOT OF LITTLE THINGS THAT WILL GO INTO
HOW THE FORECAST WILL PAN OUT TODAY AND TONIGHT. TO
BEGIN...AFTERNOON HIGHS WILL BE IN JEOPARDY DUE TO POTENTIAL CLOUD
COVER AND THE AMOUNT OF MIXING THAT WILL TAKE PLACE. NOT TO SOLD
ON THE FACT THAT AREAS WILL SEE FULL SUNSHINE THROUGH THE
DAY...OTHER THAN POCKETS OF BLUE. WITH THE OVERNIGHT
RAINFALL...GENERALLY THAT FELL NORTH OF I-80...THINK IT WILL TAKE
A LITTLE BIT OF TIME TO WARM...AND THAT AREAS TO THE SOUTH SHOULD
STILL SEE THE WARMEST OF TEMPS...AND THEY MAY BE UNDERDONE AS A
DRY SLOT MOVES THROUGH. LOW LEVEL FLOW WILL BE CONSIDERABLE INTO
THE AFTERNOON HOURS...AND AM ON THE FENCE WITH RESPECT TO A
POTENTIAL ADVISORY. EXPECT WINDS TO INCREASE INTO THIS AFTERNOON IN
THE WARM SECTOR AND COULD FORESEE GUSTS APPROACHING 40-45 MPH INTO
THE AFTERNOON. TECHNICAL CRITERIA FOR AN ADVISORY IS TO SEE
SUSTAINED WINDS OF 30 TO 39 MPH LASTING AN HOUR OR LONGER OR WINDS
OF 45 TO 57 MPH FOR ANY DURATION. WHILE FORECAST SOUNDINGS
INDICATE THAT THE AREA SHOULD BE MIXING UP TO H9 TO H85...AND SHOW
THE TOP OF THE MIXED CHANNEL HITTING MID TO UPPER 40 TO 50 KT
RANGE...STILL HAVING A HARD TIME SEEING COMPLETELY EFFICIENT
MIXING HAPPENING UNDER THE MOIST WARM ADVECTION REGIME. WILL HIT
WORDING AT THE UPPER NON ADVISORY THRESHOLD...AND DETAIL A BIT IN
THE HWO AS WELL.
EARLY EVENING HOURS THEN WILL BE THE MAIN EVENT FOR ACTIVITY ACROSS
THE AREA AS A COLD FRONT WILL BRING THE NEXT CHANCE FOR STRONG TO
POSSIBLY SEVERE STORMS TO THE ENTIRE AREA. SOUNDINGS FOR THE
CHICAGO AREA LOOK...SLOPPY INTO THE AFTERNOON AND EVENING HOURS
THOUGH THERE IS AN INDICATION THAT WE WILL BE MILDLY CAPPED WITH
THE INCREDIBLE WAA ONGOING. EVENTUALLY THE AREA WILL BECOME
UNSTABLE AND GUIDANCE IS INDICATING THAT CAPE VALUES OF BETWEEN
600-1000 J/KG ACROSS OUR EAST...WITH 1000-1200 J/KG WEST WILL BE
ON HAND TO START OUT. BASICALLY UNIDIRECTIONAL SHEAR WILL BE IN
PLACE AND EARLY MORNING INDICATIONS OF 0-1 BLK SHEAR VALUES OF
30-35 KT AND 0-6 VALUES OF 45 TO 50 KT WILL INCREASE TO NEAR 60 KT
IN THE EVENING AND WILL SUPPORT SEMI DISCREET CELLULAR ACTIVITY.
DESPITE THE LOW WEAKENING INTO THE EVENING AND BEING SO FAR
DISPLACED FROM OUR AREA...STILL ANTICIPATE SOME OF THE STORMS TO
APPROACH AND BECOME SEVERE AS THE FRONT RIPS THROUGH. GENERALLY
EXPECT RAPID DEVELOPMENT OF THUNDERSTORMS ACROSS SOUTHEASTERN IA
AND NORTHWESTERN MISSOURI BY THE EARLY AFTERNOON HOURS....WITH
ACTIVITY SHIFTING EAST THROUGH THE EVENING AND IMPACTING THE
CHICAGO METRO IN OR AROUND THE AROUND THE 7PM HOUR. THE BIGGEST
THREAT FOR ANY SEVERE ACTIVITY TOMORROW WILL BE HAIL AND DAMAGING
WINDS. AT THIS POINT AN ISOLATED TORNADO THREAT DOES EXIST AT
LEAST FOR A TIME GIVEN THE LOW LEVEL WIND FIELDS AND POTENTIAL FOR
GOOD LOW LEVEL INSTABILITY...BUT THE INCREASED LIKELIHOOD WILL BE
TIED CLOSER TO THE SURFACE LOW AND WARM FRONTAL INTERSECTION MORE
IN THE VICINITY OF LA CROSS. THAT SAID...ANY POTENTIAL BOUNDARY
THAT IS KICKED OUT BY DECAYING STORMS...MAY MODIFY THE WIND FIELD
ENOUGH FOR TORNADOGENESIS TO TAKE PLACE. ANY ACTIVITY SHOULD EXIT
THE AREA BY OR DURING THE OVERNIGHT HOURS. SPC`S DAY 1 OUTLOOK HAS
SHIFTED THE MODERATE BOX A LITTLE TO THE SOUTH AS THE MAIN SURFACE
LOW IS NOT MOVING AS QUICKLY AS MODELS PROGGED IT OVER THE LAST
FEW DAYS.
BEYOND THE TS ACTIVITY INTO THE EVENING...IT WILL TAKE SOME TIME FOR
WINDS TO SHIFT TO THE WEST AND FOR THE DRYING TO COMMENCE. WITH THE
LINGERING CLOUD COVER AND LIMITED COLDER AIR ADVECTION...MOST AREAS
SHOULD STAY RELATIVELY WARM TONIGHT AND INTO SUNDAY MORNING...WITH
OVERNIGHT LOWS ONLY FALLING TO THE MID 50S GENERALLY EAST OF I
57...AND A FEW DEGREES COOLER WEST AND NORTH.
NOT MUCH TIME TO GET DETAILED IN THE EXTENDED FORECAST WITH THE
ONGOING STORMS LAST NIGHT AND ACTIVE PERIOD EXPECTED TONIGHT. THE
MAIN UPPER TROUGH WILL MOVE EAST AND RIDGING WILL GRADUALLY SLIDE
OVER...BRINGING ANOTHER COOL DOWN BY MID WEEK. GUIDANCE IS STILL
AT ODDS WITH HOW THE END OF THE WEEK WILL PAN OUT...BUT CHANCES
FOR FROST LOOK GOOD NORTH OF I-88 MONDAY NIGHT AND INTO TUESDAY AS
OVERNIGHT LOWS TUMBLE. SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* TSRA MOVING THROUGH THE TERMINALS THIS EVENING. PERIODS OF HEAVY
RAIN...HAIL...FREQUENT LIGHTNING...AND BRIEF IFR VIS POSSIBLE.
* STRONG SOUTH-SOUTHWEST WINDS GUSTING TO 30-35 KT THROUGH THE DAY
AND INTO THE EVENING...NOT ASSOCIATED WITH THUNDERSTORMS.
IZZI
//DISCUSSION...UPDATED 18Z...
STRONG LOW PRESSURE CENTER MOVING INTO MINNESTOA BY THIS EVENING
WILL SUPPORT REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS BY THIS
EVENING. THE MOST FAVORABLE AREA FOR REDEVELOPMENT IS TO THE WEST
OF THE TERMINALS...AND THEN MOVING EAST THROUGH THE EVENING. LOW
LEVEL SOUTH-SOUTHWEST WINDS ASSOCIATED WITH THE LOW WILL GUST INTO
THE 30-35 KT RANGE AT TIMES DURING THE AFTERNOON AND EVENING.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN NO PRECIPITATION THROUGH THE AFTERNOON.
* MEDIUM CONFIDENCE ON TIMING TS MOVING THROUGH THIS EVENING.
* MEDIUM TO HIGH CONFIDENCE ON WIND TRENDS.
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...
TUESDAY...VFR.
WEDNESDAY...VFR. CHC MVFR CIGS W/SHRA ISO TSRA
MIDDAY/AFTN.
THURSDAY...VFR. CHC SHRA.
FRIDAY...VFR. CHC SHRA ISO TSRA.
SATURDAY...VFR. CHC SHRA.
LENNING
&&
.MARINE...
350 AM CDT
DEEPENING LOW PRESSURE MOVING OUT OF THE PLAINS WILL REACH
SOUTHERN MINNESOTA THIS EVENING AND MOVE INTO NORTHERN LAKE
MICHIGAN BY MONDAY MORNING. WARM SOUTHERLY WINDS WILL BE GUSTING
INTO THE 35 KT RANGE OVER LAND AND NEARSHORE WATERS TODAY...BUT
THE STRONG STABLE LAYER OVER THE COOL OPEN WATERS IS EXPECTED TO
HINDER ANY MIXING DOWN TO THE LAKE SURFACE. THOSE ON HIGHER
VESSELS COULD SEE AN OCCASIONAL GUST INTO THE MIDDLE 30S...BUT THE
GALE WARNING FOR THE OPEN WATERS APPEARS MUCH MORE LIKELY ON
MONDAY WHEN COLD AIR STARTS WORKING IN ON WEST AND NORTHWEST WINDS
BEHIND A COLD FRONT THAT WILL CROSS THE LAKE EARLY MONDAY. THE
NORTH HALF OF THE LAKE CLOSER TO THE LOW IS EXPECTED TO SEE
SLIGHTLY HIGHER WIND GUSTS MONDAY...BUT THESE WOULD START LATER IN
THE DAY COMPARED TO THE SOUTH HALF. LIKEWISE...GALES ALSO ARE
EXPECTED IN THE NEARSHORE WATERS MONDAY...BUT WITH TWO HEADLINES
ALREADY IN EFFECT TODAY...WILL NOT BE ISSUING A WATCH FOR THAT
AREA THIS MORNING. THE IDEA OF JUST CONTINUING TODAY`S GALE
WARNING ALL NIGHT INTO MONDAY WAS CONSIDERED...BUT THERE APPEARS
TO BE A PERIOD OF SOMEWHAT LIGHTER WINDS OVERNIGHT INTO EARLY
MONDAY.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 1 AM MONDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 1 AM
MONDAY.
LM...GALE WATCH...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...10 AM MONDAY TO 9 PM
MONDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 7 PM
SUNDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...3 PM MONDAY TO 1 AM TUESDAY.
GALE WARNING...NEARSHORE WATERS UNTIL 7
PM MONDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
235 PM CDT SUN APR 15 2012
.MESOSCALE DISCUSSION...
235 PM CDT
THE 18Z SOUNDINGS FROM DVN AND ILX BOTH SHOW A MUCH MORE STOUT
CAPPING INVERSION PRESENT THAN HAD BEEN FORECAST BY THE VARIOUS
MODELS. DESPITE FAIRLY EXTENSIVE AND IN SOME CASES DENSE
CIRRUS...SFC TEMPS CONTINUE TO WARM WHICH IS HELPING WEAKEN THE
BOUNDARY LAYER CONVECTIVE INHIBITION SOMEWHAT...THOUGH SERIES OF
ACARS SOUNDINGS OUT OF MDW SHOW EVIDENCE OF INCREASING MID LEVEL
SUBSIDENCE...LIKELY IN THE WAKE OF THE LEAD WAVE THAT PASSED BY THIS
MORNING.
SOME MOISTENING/COOLING HAS BEEN NOTED ON WATER VAPOR IMAGERY OVER
SOUTHERN MISSOURI LIKELY IN ASSOCIATION WITH INCREASING ASCENT WITH
APPROACHING MID/UPPER LEVEL JET ROUNDING THE BASE OF THE TROUGH.
GIVEN THE CAPPING IN PLACE SUSPECT THAT MORE THE ROBUST/WIDESPREAD
CONVECTION IN OUR AREA MAY END UP WAITING UNTIL THE ARRIVAL OF THIS
FORCING LATE THIS AFTERNOON INTO THIS EVENING. FORECAST SOUNDINGS
FROM THE RUC DO SUGGEST THAT THIS WILL OCCUR...SO THE THREAT STILL
IS THERE FOR SEVERE WEATHER IS STILL THIS EVENING.
ASSUMING MORE INTENSE CONVECTION DOES INDEED GET GOING IN THE AREA
THIS EVENING...ITS LOOKING MORE LIKELY THAT IT WILL BE A VERY HIGH
SHEAR/LOW CAPE TYPE ENVIRONMENT WITH MAINLY A DAMAGING WIND THREAT.
THOUGH AS ALLUDED TO IN THE PREVIOUS MESO-AFD...THE EXTREME SHEAR
DOES CERTAINLY RAISE CONCERNS ABOUT THE TORNADO POTENTIAL DESPITE
THE EXPECTED LIMITED INSTABILITY.
IZZI
&&
.DISCUSSION...
1026 AM CDT
VERY DEEP //989MB// SFC LOW OVER CENTRAL NEBRASKA WILL CONTINUE TO
LIFT NORTHEAST TOWARD THE UPPER MISSISSIPPI VALLEY THROUGH
TONIGHT. PRESSURE GRADIENT AROUND THIS LOW HAS ALREADY RESULTED IN
WINDS GUSTING TO BETWEEN 30 AND 40 MPH THIS MORNING. WINDS SHOULD
CONTINUE TO INCREASE THIS AFTERNOON WITH SOME MIXED SUNSHINE AND
HEATING/MIXING...AND WHILE WE WILL SEE SOME DIURNAL SLACKENING OF
THE WINDS JUST OF THE DECK STILL THINK GUSTS OVER 40 MPH COULD
OCCUR THIS AFTERNOON. BY THIS EVENING SHOULD SEE WINDS JUST OFF
THE DECK RAPIDLY INCREASE TO 50-60KT 2000FT AGL AS EARLY AS 00Z
AND WITH STRONG PRESSURE FALLS/ISALOBARIC PUSH MAY SEE VERY LITTLE
DECOUPLING THIS EVENING WITH SURFACE WINDS PROBABLY INCREASING
EVEN FURTHER THIS EVENING. GIVEN THIS POTENTIAL HAVE OPTED TO
HOIST A WIND ADVISORY THROUGH 06Z FOR THE ENTIRE CWA.
WILL SHOOT TO HAVE A CONVECTIVE MESOSCALE AFD ISSUED PRIOR TO 17Z.
IZZI
//PREV DISCUSSION...
345 AM CDT
THE BULK OF THE OVERNIGHT SHOWER AND THUNDERSTORM ACTIVITY WILL BE
ON THE WANE AS WE APPROACH SUNRISE...WITH THE OVERALL ORIENTATION OF
THE REFLECTIVITY RETURNS TO SHIFT TO THE NORTHEAST AND EVENTUALLY
OUT OF THE CWA BY THE EARLY MORNING HOURS AS A SHORTWAVE SHOOTS OFF
TO MICHIGAN. HIGH RESOLUTION GUIDANCE HAD A DIFFICULT TIME DEALING
WITH SMALL SCALE FEATURES TONIGHT...AND NOTHING CAUGHT AN MCV
CHARGING EAST OUT OF KANSAS. IT WAS WITH THIS AREA THAT AN
IMPRESSIVE SQUALL WAS CHARGING THROUGH...PLOWING INTO IOWA AND
EVENTUALLY ACROSS OUR AREA. BY THE TIME IT HIT NORTH CENTRAL AND
NORTHEASTERN ILLINOIS...IT WEAKENED CONSIDERABLY AS THE ATMOSPHERE
WEST OF THE MISSISSIPPI WAS MUCH MORE PRIMED WHEN COMPARED TO
ACROSS THE CWA. HOWEVER...SPC ANALYSIS OF H8 MOISTURE TRANSPORT IS
INCREDIBLE AND WAS HELPING TO ADVECT IN HIGH PRECIPITABLE WATER
INTO THE AREA AND ALSO HELP TO PUSH SOME INSTABILITY ACROSS.
THE MAIN SURFACE LOW RESPONSIBLE FOR THE CURRENT WEATHER
SITUATION ACROSS THE PLAINS WILL LIFT NORTHEAST AND THROUGH
WISCONSIN BY THIS AFTERNOON. SOUTH OF THIS LOW IS A COLD FRONT
THAT WILL SWEEP ACROSS NORTHERN ILLINOIS AND NORTHWESTERN INDIANA
IN THE EVENING HOURS AND BRING THE NEXT CHANCES FOR SHOWERS AND
THUNDERSTORMS. THERE ARE A LOT OF LITTLE THINGS THAT WILL GO INTO
HOW THE FORECAST WILL PAN OUT TODAY AND TONIGHT. TO
BEGIN...AFTERNOON HIGHS WILL BE IN JEOPARDY DUE TO POTENTIAL CLOUD
COVER AND THE AMOUNT OF MIXING THAT WILL TAKE PLACE. NOT TO SOLD
ON THE FACT THAT AREAS WILL SEE FULL SUNSHINE THROUGH THE
DAY...OTHER THAN POCKETS OF BLUE. WITH THE OVERNIGHT
RAINFALL...GENERALLY THAT FELL NORTH OF I-80...THINK IT WILL TAKE
A LITTLE BIT OF TIME TO WARM...AND THAT AREAS TO THE SOUTH SHOULD
STILL SEE THE WARMEST OF TEMPS...AND THEY MAY BE UNDERDONE AS A
DRY SLOT MOVES THROUGH. LOW LEVEL FLOW WILL BE CONSIDERABLE INTO
THE AFTERNOON HOURS...AND AM ON THE FENCE WITH RESPECT TO A
POTENTIAL ADVISORY. EXPECT WINDS TO INCREASE INTO THIS AFTERNOON IN
THE WARM SECTOR AND COULD FORESEE GUSTS APPROACHING 40-45 MPH INTO
THE AFTERNOON. TECHNICAL CRITERIA FOR AN ADVISORY IS TO SEE
SUSTAINED WINDS OF 30 TO 39 MPH LASTING AN HOUR OR LONGER OR WINDS
OF 45 TO 57 MPH FOR ANY DURATION. WHILE FORECAST SOUNDINGS
INDICATE THAT THE AREA SHOULD BE MIXING UP TO H9 TO H85...AND SHOW
THE TOP OF THE MIXED CHANNEL HITTING MID TO UPPER 40 TO 50 KT
RANGE...STILL HAVING A HARD TIME SEEING COMPLETELY EFFICIENT
MIXING HAPPENING UNDER THE MOIST WARM ADVECTION REGIME. WILL HIT
WORDING AT THE UPPER NON ADVISORY THRESHOLD...AND DETAIL A BIT IN
THE HWO AS WELL.
EARLY EVENING HOURS THEN WILL BE THE MAIN EVENT FOR ACTIVITY ACROSS
THE AREA AS A COLD FRONT WILL BRING THE NEXT CHANCE FOR STRONG TO
POSSIBLY SEVERE STORMS TO THE ENTIRE AREA. SOUNDINGS FOR THE
CHICAGO AREA LOOK...SLOPPY INTO THE AFTERNOON AND EVENING HOURS
THOUGH THERE IS AN INDICATION THAT WE WILL BE MILDLY CAPPED WITH
THE INCREDIBLE WAA ONGOING. EVENTUALLY THE AREA WILL BECOME
UNSTABLE AND GUIDANCE IS INDICATING THAT CAPE VALUES OF BETWEEN
600-1000 J/KG ACROSS OUR EAST...WITH 1000-1200 J/KG WEST WILL BE
ON HAND TO START OUT. BASICALLY UNIDIRECTIONAL SHEAR WILL BE IN
PLACE AND EARLY MORNING INDICATIONS OF 0-1 BLK SHEAR VALUES OF
30-35 KT AND 0-6 VALUES OF 45 TO 50 KT WILL INCREASE TO NEAR 60 KT
IN THE EVENING AND WILL SUPPORT SEMI DISCREET CELLULAR ACTIVITY.
DESPITE THE LOW WEAKENING INTO THE EVENING AND BEING SO FAR
DISPLACED FROM OUR AREA...STILL ANTICIPATE SOME OF THE STORMS TO
APPROACH AND BECOME SEVERE AS THE FRONT RIPS THROUGH. GENERALLY
EXPECT RAPID DEVELOPMENT OF THUNDERSTORMS ACROSS SOUTHEASTERN IA
AND NORTHWESTERN MISSOURI BY THE EARLY AFTERNOON HOURS....WITH
ACTIVITY SHIFTING EAST THROUGH THE EVENING AND IMPACTING THE
CHICAGO METRO IN OR AROUND THE AROUND THE 7PM HOUR. THE BIGGEST
THREAT FOR ANY SEVERE ACTIVITY TOMORROW WILL BE HAIL AND DAMAGING
WINDS. AT THIS POINT AN ISOLATED TORNADO THREAT DOES EXIST AT
LEAST FOR A TIME GIVEN THE LOW LEVEL WIND FIELDS AND POTENTIAL FOR
GOOD LOW LEVEL INSTABILITY...BUT THE INCREASED LIKELIHOOD WILL BE
TIED CLOSER TO THE SURFACE LOW AND WARM FRONTAL INTERSECTION MORE
IN THE VICINITY OF LA CROSS. THAT SAID...ANY POTENTIAL BOUNDARY
THAT IS KICKED OUT BY DECAYING STORMS...MAY MODIFY THE WIND FIELD
ENOUGH FOR TORNADOGENESIS TO TAKE PLACE. ANY ACTIVITY SHOULD EXIT
THE AREA BY OR DURING THE OVERNIGHT HOURS. SPC`S DAY 1 OUTLOOK HAS
SHIFTED THE MODERATE BOX A LITTLE TO THE SOUTH AS THE MAIN SURFACE
LOW IS NOT MOVING AS QUICKLY AS MODELS PROGGED IT OVER THE LAST
FEW DAYS.
BEYOND THE TS ACTIVITY INTO THE EVENING...IT WILL TAKE SOME TIME FOR
WINDS TO SHIFT TO THE WEST AND FOR THE DRYING TO COMMENCE. WITH THE
LINGERING CLOUD COVER AND LIMITED COLDER AIR ADVECTION...MOST AREAS
SHOULD STAY RELATIVELY WARM TONIGHT AND INTO SUNDAY MORNING...WITH
OVERNIGHT LOWS ONLY FALLING TO THE MID 50S GENERALLY EAST OF I
57...AND A FEW DEGREES COOLER WEST AND NORTH.
NOT MUCH TIME TO GET DETAILED IN THE EXTENDED FORECAST WITH THE
ONGOING STORMS LAST NIGHT AND ACTIVE PERIOD EXPECTED TONIGHT. THE
MAIN UPPER TROUGH WILL MOVE EAST AND RIDGING WILL GRADUALLY SLIDE
OVER...BRINGING ANOTHER COOL DOWN BY MID WEEK. GUIDANCE IS STILL
AT ODDS WITH HOW THE END OF THE WEEK WILL PAN OUT...BUT CHANCES
FOR FROST LOOK GOOD NORTH OF I-88 MONDAY NIGHT AND INTO TUESDAY AS
OVERNIGHT LOWS TUMBLE. SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* STRONG LINE OF THUNDERSTORMS MOVING THROUGH THE TERMINALS THIS
EVENING. PERIODS OF HEAVY RAIN...HAIL...FREQUENT
LIGHTNING...OCNL IFR CIGS/VIS POSSIBLE.
* STRONG SOUTH-SOUTHWEST WINDS GUSTING TO 30-35 KT THROUGH THE DAY
AND INTO THE EVENING...NOT ASSOCIATED WITH THUNDERSTORMS.
PAW
//DISCUSSION...UPDATED 18Z...
STRONG LOW PRESSURE CENTER MOVING INTO MINNESTOA BY THIS EVENING
WILL SUPPORT REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS BY THIS
EVENING. THE MOST FAVORABLE AREA FOR REDEVELOPMENT IS TO THE WEST
OF THE TERMINALS...AND THEN MOVING EAST THROUGH THE EVENING. LOW
LEVEL SOUTH-SOUTHWEST WINDS ASSOCIATED WITH THE LOW WILL GUST INTO
THE 30-35 KT RANGE AT TIMES DURING THE AFTERNOON AND EVENING.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE IN NO PRECIPITATION THROUGH THE AFTERNOON.
* MEDIUM CONFIDENCE ON TIMING OF RENEWED CONVECTION AND LINE OF TS
MOVING THROUGH THIS EVENING.
* MEDIUM TO HIGH CONFIDENCE ON WIND TRENDS.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...
TUESDAY...VFR.
WEDNESDAY...VFR. CHC MVFR CIGS W/SHRA ISO TSRA
MIDDAY/AFTN.
THURSDAY...VFR. CHC SHRA.
FRIDAY...VFR. CHC SHRA ISO TSRA.
SATURDAY...VFR. CHC SHRA.
LENNING
&&
.MARINE...
350 AM CDT
DEEPENING LOW PRESSURE MOVING OUT OF THE PLAINS WILL REACH
SOUTHERN MINNESOTA THIS EVENING AND MOVE INTO NORTHERN LAKE
MICHIGAN BY MONDAY MORNING. WARM SOUTHERLY WINDS WILL BE GUSTING
INTO THE 35 KT RANGE OVER LAND AND NEARSHORE WATERS TODAY...BUT
THE STRONG STABLE LAYER OVER THE COOL OPEN WATERS IS EXPECTED TO
HINDER ANY MIXING DOWN TO THE LAKE SURFACE. THOSE ON HIGHER
VESSELS COULD SEE AN OCCASIONAL GUST INTO THE MIDDLE 30S...BUT THE
GALE WARNING FOR THE OPEN WATERS APPEARS MUCH MORE LIKELY ON
MONDAY WHEN COLD AIR STARTS WORKING IN ON WEST AND NORTHWEST WINDS
BEHIND A COLD FRONT THAT WILL CROSS THE LAKE EARLY MONDAY. THE
NORTH HALF OF THE LAKE CLOSER TO THE LOW IS EXPECTED TO SEE
SLIGHTLY HIGHER WIND GUSTS MONDAY...BUT THESE WOULD START LATER IN
THE DAY COMPARED TO THE SOUTH HALF. LIKEWISE...GALES ALSO ARE
EXPECTED IN THE NEARSHORE WATERS MONDAY...BUT WITH TWO HEADLINES
ALREADY IN EFFECT TODAY...WILL NOT BE ISSUING A WATCH FOR THAT
AREA THIS MORNING. THE IDEA OF JUST CONTINUING TODAY`S GALE
WARNING ALL NIGHT INTO MONDAY WAS CONSIDERED...BUT THERE APPEARS
TO BE A PERIOD OF SOMEWHAT LIGHTER WINDS OVERNIGHT INTO EARLY
MONDAY.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 1 AM MONDAY.
IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 1 AM
MONDAY.
LM...GALE WATCH...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...10 AM MONDAY TO 9 PM
MONDAY.
DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 7 PM
SUNDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...3 PM MONDAY TO 1 AM TUESDAY.
GALE WARNING...NEARSHORE WATERS UNTIL 7
PM MONDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
125 AM CDT SUN APR 15 2012
.MESOSCALE DISCUSSION...
110 AM CDT
THE MESOSCALE CONVECTIVE VORTEX THAT EMANATED FROM CONVECTION IN
KS/NE/IA SATURDAY AFTERNOON IS NOW DECAYING OVER SE WI AS IT
MOVES EAST. REMNANT STORMS HAVE BECOME MORE WEST-TO-EAST ORIENTED
AS THE SYSTEM HAS WEAKENED AND SYNOPTIC FORCING/FLOW/CONVERGENCE
IS TAKING OVER. CONTINUED REGENERATION OF STORMS IS SEEN PER
RADAR AND IR ANALYSIS ACROSS THE DVN CWA AS BROAD SCALE HEIGHT
FALLS WITHIN UPPER LEVEL DIFFLUENCE MOVE OVER THE AREA. THESE
WILL CONTINUE TO PROPAGATE INTO VERY RICH MOISTURE...WITH 700MB
DEW POINTS ON THE ORDER OF 0C-4C...BEING TRANSPORTED NORTHWARD ON
A 60-65 KT LOW-LEVEL JET PER PROFILER ANALYSIS. THIS IS AT A
SOMEWHAT IDEAL 90 DEGREE ANGLE INTO THE WEST-TO-EAST STORM MOTIONS
BEING OBSERVED.
THE STORMS LIE WELL WITHIN ANALYZED DEEP LAYER MOISTURE
CONVERGENCE AND ALONG AN ELEVATED THERMAL/MOISTURE
BOUNDARY...WHICH IS FORECAST TO SLOWLY MOVE NORTH THROUGH THE
OVERNIGHT BY THE RUC MODEL. THIS NORTHWARD MOTION MAY BE VERY SLOW
TO HAPPEN HOWEVER WITH SUPPRESSION IN THE WAKE OF THE MCV TO THE
NORTH OF THIS BOUNDARY ACROSS NE IA/SW WI. THUS...IN COORDINATING
WITH NESDIS...WE DO EXPECT CONTINUED EFFICIENT RAINFALL PRODUCING
THUNDERSTORMS ACROSS THE WESTERN AND NORTHERN FORECAST AREA
OVERNIGHT.
RAINFALL RATES IN THE PAST HOUR ACROSS THE DVN FORECAST AREA ARE
INDICATIVE OF THREE QUARTER TO ONE INCH OF RAIN PER HOUR
RATES IN SWATHS...AND GIVEN THE AREAL COVERAGE OF 45-50 DBZ
/WHICH CORRELATES TO AT LEAST ONE INCH OF RAIN IN CONVECTIVE
REGIMES/...EXPECT THAT TO BE THE GENERAL TREND INTO THE WESTERN
FORECAST AREA...WITH LOCALIZED HIGHER AMOUNTS LIKELY. THREE HOUR
FLASH FLOOD GUIDANCE OF 2.25 TO 3.25 INCHES SHOULD HOLD IN MOST
PLACES. WILL HAVE TO WATCH...ESPECIALLY IF ANY MORE WAVES OF
STORMS PASS OVER ROCKFORD...FOR POSSIBLE FLOOD STATEMENTS OR
WARNINGS. WOULD EXPECT IT TO BE A LOCALIZED ENOUGH THREAT FOR NO
FLOOD WATCH...BUT WILL HAVE TO RE-EVALUATE LOOKING AT THE BIG
PICTURE THROUGH SUNDAY AND SUNDAY NIGHT.
MTF
&&
.DISCUSSION...
838 PM CDT
UPDATE FOR TONIGHT...
DEEPENING SURFACE LOW CURRENTLY OVER CENTRAL NEB WITH GREATEST
PRESSURE FALLS TO THE N THROUGH ENE OF THE LOW ACROSS SD...SW MN
AND NW IA. A SMALLER SEPARATE PRESSURE FALL CENTER HAS MOVED E
FROM SE NEB TO S CENTRAL IA OVER THE LAST 3 HRS JUST AHEAD OF THE
ENE MOVING MCV...WHICH IS NOW SW OF DSM. CONTINUING ON THIS PATH
WOULD TAKE IT TO THE WESTERN IL-WI STATE LINE 05-06Z TIME FRAME
AND THEN ON INTO S CENTRAL WI OVERNIGHT.
LOW LEVELS ARE STABLE ACROSS N CENTRAL AND NE IL...AS WELL AS NW
IND WITH DEW POINTS STILL IN THE 50S N OF THE WARM FRONT AND
TEMPERATURES HELD DOWN TO MAINLY THE MID 60S AS DENSE ANVIL
BLOW-OFF COVERED THE AREA THROUGH THE DAY. HOWEVER...MODELS
INDICATE THAT LOCAL MID LEVELS WILL DESTABILIZE DURING THE REST
OF THE EVENING WITH SHOWALTER INDEX FALLING TO -2...MU CAPE
RISING TO 400-600 J/KG AND TOTAL TOTALS REACHING 50+ BY 06Z.
VAD AND PROFILER WINDS HAVE SHOWN A STRENGTHENING OF THE LLJ
PUSHING E TO THE MS RIVER AND MODELS CONTINUE THIS TREND
EXTENDING THE NOSE OF THE LLJ NE TO SOUTHERN LAKE MI AND SOUTHERN
LOWER MI BY 12Z. WITH INCREASING ISENTROPIC LIFT IN THE MID
LEVELS OCCURRING BELIEVE THAT SHOWERS AND T-STORMS IN SE IA AND
EXTREME NE MO WILL CONTINUE TO SPREAD E ACROSS THE MS RIVER AND
LIFT NORTHEASTWARD AND EVENTUALLY OVER THE FORECAST AREA DURING
THE LATE EVENING AND OVERNIGHT N OF THE WARM FRONT TO BE LIFTING
ACROSS CENTRAL TO NORTHERN IL DURING THE NIGHT.
LATEST RUNS OF HI RESOLUTION MODELS INCLUDING HRRR...RUC13 AND
VSREF HAVE RAIN REACHING IROQUOIS AND LIVINGSTON COUNTIES 04-05Z
AND INTO THE CHICAGO METRO AREA 06-07Z. THIS TIMING LOOKS
REASONABLE.
TRS
//PREV DISCUSSION...
305 PM CDT
MAIN CONCERN FOR THE AFTERNOON UPDATE WILL FOCUS ON SEVERE WEATHER
POTENTIAL FOR TOMORROW...BUT CHANCES FOR THUNDERSTORMS OVERNIGHT
TONIGHT WILL BE A CONCERN AS WELL.
FOR THE REMAINDER OF THIS AFTERNOON AND INTO EARLY THIS
EVENING...CONDITIONS ACROSS THE AREA WILL BE RELATIVELY QUIET AS THE
EARLIER SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A LEAD SHORTWAVE
HAVE MOVED WELL EAST INTO THE UPPER OHIO VALLEY. IN THE MEAN
TIME...LOW PRESSURE IS DEVELOPING OVER THE WESTERN PLAINS WITH A
WARM FRONT EXTENDING EAST THROUGH NRN MO AND CNTRL IL/IN. THIS WARM
FRONT WILL BECOME THE FOCUS FOR NEW THUNDERSTORM DEVELOPMENT
OVERNIGHT TONIGHT AS IT LIFTS NWD. ANTICIPATE THAT THE WRMFNT WILL
TRAVERSE THE CWA BTWN 03Z-09Z WITH OVERRUNNING PCPN AND ELEVATED
CONVECTION POSSIBLE NORTH OF THE WARM FRONT THROUGH THE EVENING AND
POSSIBLY TRANSITIONING TO MORE SFC BASED CONVECTION AS THE WARM
SECTOR OVERSPREADS THE ENTIRE CWA DURG THE EARLY MORNING HOURS.
GIVEN THE MAIN SFC LOW IS WELL TO THE WEST AND THE LESS THAN
FAVORABLE TIME THAT THE WARM FRONT IS LIFTING THROUGH THE CWA...DO
NOT ANTICIPATE A SGFNT SEVERE THREAT WITH STORMS DEVELOPING
OVERNIGHT TONIGHT...BUT WITH DEEP LAYER MOISTURE ON THE
INCREASE...OCNL HEAVY DOWNPOURS AND PERIODS OF SMALL HAIL ARE VERY
LIKELY.
THE MAIN FOCUS FOR THE SEVERE WEATHER CONCERN WILL BE TAKING SHAPE
FOR TOMORROW. THE SHORT RANGE MODEL GUIDANCE IS CONVERGING ON
REASONABLY DECENT CONSISTENCY IN DEEPENING THE WRN PLAINS SFC LOW AS
IT LIFTS NEWD THROUGH THE PLAINS AND INTO THE UPPER MISSOURI VALLEY
BY SUNDAY AFTERNOON AND INTO THE UPPER MISSOURI VALLEY BY SUNDAY
EVENING. THROUGH THE DAY...A STRONG LOW LEVEL JET WILL SET UP WITH
SWLY WINDS OF 55-60KT OVER NRN IL AND INTO WISCONSIN. SFC WINDS ARE
EXPECTED TO BACK SSELY THROUGH THE DAY TOMORROW ENHANCING THE LOW
LEVEL SHEAR PROFILE. STRONG WARM ADVECTION WILL ALLOW SFC
TEMPERATURES TO RISE INTO THE UPPER 70S TO LOWER 80S. THE
COMBINATION OF HEAT AND HUMIDITY WILL SET UP A VERY UNSTABLE
ENVIRONMENT. MODEL SOUNDINGS INDICATE SOME WEAK CAPPING INTO THE
EARLY AFTERNOON...BUT EXPECTED SFC WARMING SHOULD HAVE NO PROBLEM
OVERCOMING AND WEAK CAPPING AND CONVECTIVE INITIATION IS LIKELY
OVER THE WRN PORTIONS OF THE CWA...FROM I-39 TO THE MISSISSIPPI
RIVER DURING THE AFTERNOON. GIVEN THE MODEST LOW LEVEL WIND
SHEAR...THE INITIAL CONVECTIVE MODE WILL BE CONDUCIVE TO DISCRETE
SUPERCELLS WITH LARGE HAIL...STRONG DAMAGING WINDS AND EVEN ISOLATED
TORNADOES ARE A POSSIBILITY. ALSO THROUGH THE DAYTIME
HOURS...STRONG SYNOPTIC WINDS WILL BE A CONCERN EVEN BEFORE
CONVECTIVE INITIATION. A STRENGTHENING PRESSURE GRADIENT EAST OF
THE DEEPENING SFC LOW WILL DRIVE SLY WINDS TO 25KT THROUGH THE
MORNING HOURS AND WITH DAYTIME WARMING...MIXING WILL BEGIN TO TAP
THE STRONG WINDS ALOFT AND EXPECT SYNOPTIC SCALE WIND GUSTS OF 35 TO
40KT OVER THE ENTIRE CWA IN ADDITION TO ANY LOCALLY HIGHER
THUNDERSTORM GENERATED WIND GUSTS.
BY EARLY EVENING...THE DISCRETE SUPERCELL THREAT SHOULD MORPH INTO A
LINEAR SQUALL LINE MODE. AT THIS TIME...EXPECT THAT THE WRN
PORTIONS OF THE CWA...GENERALLY ALONG AND WEST OF THE I-39 CORRIDOR
WILL HAVE THE GREATEST DISCRETE SUPERCELL POTENTIAL DURING THE
AFTERNOON. THE TRANSITION OVER TO A LINEAR SQUALL LINE MODE SHOULD
OCCUR DURING THE EARLY EVENING HOURS OVER THE CENTRAL PORTIONS OF
THE CWA...GENERALLY BETWEEN I-39 AND I-55...AND THEN STEADILY MARCH
EWD THROUGH THE NIGHT...EXITING THE NWRN INDIANA COUNTIES DURG THE
EARLY MORNING HOURS. WITH THE TRANSITION FROM DISCRETE SUPERCELL TO
LINEAR SQUALL LINE...THE MAIN SEVERE THREAT WILL FOCUS ON STRONG
DAMAGING WINDS. LOCALLY HEAVY RAINFALL MAY ALSO BECOME A CONCERN
OVERNIGHT AS PRECIPITABLE WATER VALUES OVER THE AREA SHOULD BE IN
EXCESS OF 1.5 INCHES AND ANY ECHO TRAINING ALONG THE MAIN CONVECTIVE
LINE COULD LEAD TO LOCALIZED FLASH FLOODING.
BY DAYBREAK MONDAY MORNING...THE MAIN UPPER TROUGH SHOULD PUSH
THROUGH THE UPPER MIDWEST AND GREAT LAKES REGIONS...FORCING THE SFC
COLD FRONT EAST OF THE CWA. THIS SHOULD BRING A QUICK END TO ANY
PCPN POTENTIAL AND MONDAY SHOULD BRING DECREASING CLOUD COVER AND
LITTLE DIURNAL TEMPERATURE SWING THROUGH THE DAY WITH PERSISTENT
COLD ADVECTION SETTING UP BEHIND THE COLD FRONT. TEMPERATURES ON
MONDAY SHOULD ONLY BE IN THE MIDDLE 50S TO MIDDLE 60S. HIGH
PRESSURE WILL QUICKLY BUILD IN OVER MONDAY NIGHT AND
TUESDAY...KEEPING CONDITIONS RELATIVELY COOLER AND DRIER.
FOR THE EXTENDED PERIOD...FROM WEDNESDAY THROUGH SATURDAY...A
RELATIVELY HIGH AMPLITUDE...BUT PROGRESSIVE PATTERN WILL SET UP.
THE NEXT SIGNIFICANT CHANCE FOR PCPN WILL BE ON THURSDAY NIGHT AND
FRIDAY AS A NRN STREAM SHORT WAVE DROPPING OUT OF THE
ROCKIES...LEADING TO STRONG SFC DEVELOPMENT OVER THE CNTRL PLAINS.
THE MAIN SFC LOW SHOULD TRACK THROUGH THE LOCALLY LATE THURSDAY
NIGHT AND FRIDAY...BRINGING THE NEXT CHANCE FOR SHOWERS AND
THUNDERSTORMS TO THE AREA.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* THUNDERSTORMS OVERNIGHT AND TOWARD MORNING WITH ASSOCIATED LOW
CIGS/VSBYS.
* ADDITIONAL THUNDERSTORMS POSSIBLE DURING THE DAY...MOST LIKELY
LATER TOWARD AFTERNOON AND EVENING.
LENNING
//DISCUSSION...UPDATED 06Z...
RADAR AND LIGHTNING DISPLAY AT THIS HOUR SHOWS LINES OF
THUNDERSTORMS STRETCHING FROM THE CHICAGO AREA WEST ACROSS IOWA
INTO SOUTHERN MINNESOTA...THEN SOUTH IN A NEARLY UNBROKEN SWATH
FROM MINNESOTA INTO TEXAS. THE FIRST LINE OF STORMS TO REACH THE
TERMINALS HAS MOSTLY MOVED THROUGH MDW AT THIS TIME...ALTHOUGH
ORD IS CLOSER TO THE EMBEDDED NORTH-SOUTH ORIENTED SECTIONS OF
THE LINE AND WILL SEE MORE PROLONGED TSRA ACTIVITY. MDW WILL SEE A
SHORT BREAK BEFORE THE NEXT ROUND ARRIVES AROUND 08-09Z...WHILE
ORD MAY SEE ONLY A SHORT BREAK OR NONE AT ALL.
THE BIGGER QUESTIONS CENTER AROUND DAYBREAK WHEN TRAFFIC IS
SCHEDULED TO PICK UP. GENERALLY THE THOUGHT IS OVERNIGHT ACTIVITY
WILL DISSIPATE OR LIFT NORTH BY MORNING...WITH THE NEXT ROUND
ARRIVING WHEN THE LINE NOW RUNNING FROM MN TO TX REACHES THE AREA
LATE IN THE DAY.
LENNING
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE OF MULTIPLE ROUNDS OF THUNDERSTORMS OVERNIGHT.
* LOW CONFIDENCE ON COVERAGE OF STORMS INTO THE 12-13Z PERIOD
WHEN TRAFFIC STARTS TO PICK UP.
* LOW CONFIDENCE ON COVERAGE OF ANY TSRA ACTIVITY DURING THE
MORNING AND AFTERNOON.
* MEDIUM TO HIGH CONFIDENCE OF ANOTHER ROUND OF STORMS LATER IN
THE DAY.
LENNING
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...VFR. CHC MVFR W/CHC SHRA EARLY.
TUESDAY...VFR.
WEDNESDAY...VFR. CHC MVFR CIGS W/SHRA ISO TSRA MIDDAY/AFTN.
THURSDAY...VFR. CHC SHRA.
FRIDAY...VFR. CHC SHRA ISO TSRA.
BEACHLER
&&
.MARINE...
257 PM...FORECAST REMAINS ACTIVE THROUGH MONDAY NIGHT WITH SOME
UNCERTAINTY REGARDING HOW HIGH WIND SPEEDS/GUSTS WILL BECOME. LOW
PRESSURE OVER WESTERN ONTARIO WILL MOVE EAST INTO NORTHERN QUEBEC
BY SUNDAY AFTERNOON. A TRAILING FRONTAL BOUNDARY FROM THIS LOW
WILL LIKELY SAG SOUTH ACROSS FAR NORTHERN LAKE MICHIGAN TONIGHT
TURNING WINDS EASTERLY. UNTIL THEN...THE GRADIENT WILL SUPPORT 15
TO 25 KTS ON THE NORTH END OF THE LAKE INTO EARLY THIS EVENING.
MEANWHILE LOW PRESSURE OVER EASTERN COLORADO WILL MOVE NORTHEAST
ACROSS THE PLAINS TONIGHT AND SUNDAY REACHING THE UPPER PENINSULA
OF MICHIGAN BY MONDAY MORNING. THE GRADIENT WILL TIGHTEN AS THIS
LOW APPROACHES. BUT WITH STRONG WARM AIR SPREADING OVER THE COOLER
WATER...CONFIDENCE REGARDING JUST HOW STRONG THE WINDS WILL BECOME
OVER THE OPEN WATERS REMAINS LOW. ITS POSSIBLE THAT THE GRADIENT
MAY BECOME TIGHT ENOUGH FOR LOW END GALES EVEN WITH A LACK OF
MIXING. IF THIS WERE TO OCCUR...THE BEST TIMING WOULD LIKELY BE
SUNDAY EVENING. FOR NOW...HAVE MAINTAINED WINDS TO 30KTS. AND HAVE
ALSO MAINTAINED THE GALE WATCH FOR THE INDIANA/ILLINOIS NEARSHORE
WATERS WITH STRONG WINDS/GUSTS EXPECTED OVER LAND...SPREADING
ACROSS THE NEARSHORE WATERS. AS THE LOW ELONGATES AND LIFTS
NORTHEAST...WINDS WILL SHIFT WESTERLY BY MIDDAY MONDAY AND THEN
NORTHWEST BY MONDAY EVENING. THE GRADIENT APPEARS STRONG ENOUGH
THAT A SHORT PERIOD OF GALES WILL BE POSSIBLE ACROSS NORTHERN LAKE
MICHIGAN MONDAY AFTERNOON. HIGH PRESSURE SPREADS ACROSS THE LAKES
REGION LATE MONDAY NIGHT...CROSSING THE LAKE TUESDAY AFTERNOON
WITH A PERIOD OF LIGHT WINDS EXPECTED...ALONG WITH LAKE BREEZES ON
THE ILLINOIS/INDIANA NEARSHORE WATERS. LOW PRESSURE MOVING ACROSS
THE PLAINS TUESDAY NIGHT INTO WEDNESDAY WILL QUICKLY TIGHTEN A
SOUTHERLY GRADIENT TUESDAY NIGHT INTO WEDNESDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...6 AM SUNDAY TO NOON SUNDAY.
GALE WATCH...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...NOON
SUNDAY TO 10 PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
112 AM CDT SUN APR 15 2012
.MESOSCALE DISCUSSION...
110 AM CDT
THE MESOSCALE CONVECTIVE VORTEX THAT EMANATED FROM CONVECTION IN
KS/NE/IA SATURDAY AFTERNOON IS NOW DECAYING OVER SE WI AS IT
MOVES EAST. REMNANT STORMS HAVE BECOME MORE WEST-TO-EAST ORIENTED
AS THE SYSTEM HAS WEAKENED AND SYNOPTIC FORCING/FLOW/CONVERGENCE
IS TAKING OVER. CONTINUED REGENERATION OF STORMS IS SEEN PER
RADAR AND IR ANALYSIS ACROSS THE DVN CWA AS BROAD SCALE HEIGHT
FALLS WITHIN UPPER LEVEL DIFFLUENCE MOVE OVER THE AREA. THESE
WILL CONTINUE TO PROPAGATE INTO VERY RICH MOISTURE...WITH 700MB
DEW POINTS ON THE ORDER OF 0C-4C...BEING TRANSPORTED NORTHWARD ON
A 60-65 KT LOW-LEVEL JET PER PROFILER ANALYSIS. THIS IS AT A
SOMEWHAT IDEAL 90 DEGREE ANGLE INTO THE WEST-TO-EAST STORM MOTIONS
BEING OBSERVED.
THE STORMS LIE WELL WITHIN ANALYZED DEEP LAYER MOISTURE
CONVERGENCE AND ALONG AN ELEVATED THERMAL/MOISTURE
BOUNDARY...WHICH IS FORECAST TO SLOWLY MOVE NORTH THROUGH THE
OVERNIGHT BY THE RUC MODEL. THIS NORTHWARD MOTION MAY BE VERY SLOW
TO HAPPEN HOWEVER WITH SUPPRESSION IN THE WAKE OF THE MCV TO THE
NORTH OF THIS BOUNDARY ACROSS NE IA/SW WI. THUS...IN COORDINATING
WITH NESDIS...WE DO EXPECT CONTINUED EFFICIENT RAINFALL PRODUCING
THUNDERSTORMS ACROSS THE WESTERN AND NORTHERN FORECAST AREA
OVERNIGHT.
RAINFALL RATES IN THE PAST HOUR ACROSS THE DVN FORECAST AREA ARE
INDICATIVE OF THREE QUARTER TO ONE INCH OF RAIN PER HOUR
RATES IN SWATHS...AND GIVEN THE AREAL COVERAGE OF 45-50 DBZ
/WHICH CORRELATES TO AT LEAST ONE INCH OF RAIN IN CONVECTIVE
REGIMES/...EXPECT THAT TO BE THE GENERAL TREND INTO THE WESTERN
FORECAST AREA...WITH LOCALIZED HIGHER AMOUNTS LIKELY. THREE HOUR
FLASH FLOOD GUIDANCE OF 2.25 TO 3.25 INCHES SHOULD HOLD IN MOST
PLACES. WILL HAVE TO WATCH...ESPECIALLY IF ANY MORE WAVES OF
STORMS PASS OVER ROCKFORD...FOR POSSIBLE FLOOD STATEMENTS OR
WARNINGS. WOULD EXPECT IT TO BE A LOCALIZED ENOUGH THREAT FOR NO
FLOOD WATCH...BUT WILL HAVE TO RE-EVALUATE LOOKING AT THE BIG
PICTURE THROUGH SUNDAY AND SUNDAY NIGHT.
MTF
&&
.DISCUSSION...
838 PM CDT
UPDATE FOR TONIGHT...
DEEPENING SURFACE LOW CURRENTLY OVER CENTRAL NEB WITH GREATEST
PRESSURE FALLS TO THE N THROUGH ENE OF THE LOW ACROSS SD...SW MN
AND NW IA. A SMALLER SEPARATE PRESSURE FALL CENTER HAS MOVED E
FROM SE NEB TO S CENTRAL IA OVER THE LAST 3 HRS JUST AHEAD OF THE
ENE MOVING MCV...WHICH IS NOW SW OF DSM. CONTINUING ON THIS PATH
WOULD TAKE IT TO THE WESTERN IL-WI STATE LINE 05-06Z TIME FRAME
AND THEN ON INTO S CENTRAL WI OVERNIGHT.
LOW LEVELS ARE STABLE ACROSS N CENTRAL AND NE IL...AS WELL AS NW
IND WITH DEW POINTS STILL IN THE 50S N OF THE WARM FRONT AND
TEMPERATURES HELD DOWN TO MAINLY THE MID 60S AS DENSE ANVIL
BLOW-OFF COVERED THE AREA THROUGH THE DAY. HOWEVER...MODELS
INDICATE THAT LOCAL MID LEVELS WILL DESTABILIZE DURING THE REST
OF THE EVENING WITH SHOWALTER INDEX FALLING TO -2...MU CAPE
RISING TO 400-600 J/KG AND TOTAL TOTALS REACHING 50+ BY 06Z.
VAD AND PROFILER WINDS HAVE SHOWN A STRENGTHENING OF THE LLJ
PUSHING E TO THE MS RIVER AND MODELS CONTINUE THIS TREND
EXTENDING THE NOSE OF THE LLJ NE TO SOUTHERN LAKE MI AND SOUTHERN
LOWER MI BY 12Z. WITH INCREASING ISENTROPIC LIFT IN THE MID
LEVELS OCCURRING BELIEVE THAT SHOWERS AND T-STORMS IN SE IA AND
EXTREME NE MO WILL CONTINUE TO SPREAD E ACROSS THE MS RIVER AND
LIFT NORTHEASTWARD AND EVENTUALLY OVER THE FORECAST AREA DURING
THE LATE EVENING AND OVERNIGHT N OF THE WARM FRONT TO BE LIFTING
ACROSS CENTRAL TO NORTHERN IL DURING THE NIGHT.
LATEST RUNS OF HI RESOLUTION MODELS INCLUDING HRRR...RUC13 AND
VSREF HAVE RAIN REACHING IROQUOIS AND LIVINGSTON COUNTIES 04-05Z
AND INTO THE CHICAGO METRO AREA 06-07Z. THIS TIMING LOOKS
REASONABLE.
TRS
//PREV DISCUSSION...
305 PM CDT
MAIN CONCERN FOR THE AFTERNOON UPDATE WILL FOCUS ON SEVERE WEATHER
POTENTIAL FOR TOMORROW...BUT CHANCES FOR THUNDERSTORMS OVERNIGHT
TONIGHT WILL BE A CONCERN AS WELL.
FOR THE REMAINDER OF THIS AFTERNOON AND INTO EARLY THIS
EVENING...CONDITIONS ACROSS THE AREA WILL BE RELATIVELY QUIET AS THE
EARLIER SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A LEAD SHORTWAVE
HAVE MOVED WELL EAST INTO THE UPPER OHIO VALLEY. IN THE MEAN
TIME...LOW PRESSURE IS DEVELOPING OVER THE WESTERN PLAINS WITH A
WARM FRONT EXTENDING EAST THROUGH NRN MO AND CNTRL IL/IN. THIS WARM
FRONT WILL BECOME THE FOCUS FOR NEW THUNDERSTORM DEVELOPMENT
OVERNIGHT TONIGHT AS IT LIFTS NWD. ANTICIPATE THAT THE WRMFNT WILL
TRAVERSE THE CWA BTWN 03Z-09Z WITH OVERRUNNING PCPN AND ELEVATED
CONVECTION POSSIBLE NORTH OF THE WARM FRONT THROUGH THE EVENING AND
POSSIBLY TRANSITIONING TO MORE SFC BASED CONVECTION AS THE WARM
SECTOR OVERSPREADS THE ENTIRE CWA DURG THE EARLY MORNING HOURS.
GIVEN THE MAIN SFC LOW IS WELL TO THE WEST AND THE LESS THAN
FAVORABLE TIME THAT THE WARM FRONT IS LIFTING THROUGH THE CWA...DO
NOT ANTICIPATE A SGFNT SEVERE THREAT WITH STORMS DEVELOPING
OVERNIGHT TONIGHT...BUT WITH DEEP LAYER MOISTURE ON THE
INCREASE...OCNL HEAVY DOWNPOURS AND PERIODS OF SMALL HAIL ARE VERY
LIKELY.
THE MAIN FOCUS FOR THE SEVERE WEATHER CONCERN WILL BE TAKING SHAPE
FOR TOMORROW. THE SHORT RANGE MODEL GUIDANCE IS CONVERGING ON
REASONABLY DECENT CONSISTENCY IN DEEPENING THE WRN PLAINS SFC LOW AS
IT LIFTS NEWD THROUGH THE PLAINS AND INTO THE UPPER MISSOURI VALLEY
BY SUNDAY AFTERNOON AND INTO THE UPPER MISSOURI VALLEY BY SUNDAY
EVENING. THROUGH THE DAY...A STRONG LOW LEVEL JET WILL SET UP WITH
SWLY WINDS OF 55-60KT OVER NRN IL AND INTO WISCONSIN. SFC WINDS ARE
EXPECTED TO BACK SSELY THROUGH THE DAY TOMORROW ENHANCING THE LOW
LEVEL SHEAR PROFILE. STRONG WARM ADVECTION WILL ALLOW SFC
TEMPERATURES TO RISE INTO THE UPPER 70S TO LOWER 80S. THE
COMBINATION OF HEAT AND HUMIDITY WILL SET UP A VERY UNSTABLE
ENVIRONMENT. MODEL SOUNDINGS INDICATE SOME WEAK CAPPING INTO THE
EARLY AFTERNOON...BUT EXPECTED SFC WARMING SHOULD HAVE NO PROBLEM
OVERCOMING AND WEAK CAPPING AND CONVECTIVE INITIATION IS LIKELY
OVER THE WRN PORTIONS OF THE CWA...FROM I-39 TO THE MISSISSIPPI
RIVER DURING THE AFTERNOON. GIVEN THE MODEST LOW LEVEL WIND
SHEAR...THE INITIAL CONVECTIVE MODE WILL BE CONDUCIVE TO DISCRETE
SUPERCELLS WITH LARGE HAIL...STRONG DAMAGING WINDS AND EVEN ISOLATED
TORNADOES ARE A POSSIBILITY. ALSO THROUGH THE DAYTIME
HOURS...STRONG SYNOPTIC WINDS WILL BE A CONCERN EVEN BEFORE
CONVECTIVE INITIATION. A STRENGTHENING PRESSURE GRADIENT EAST OF
THE DEEPENING SFC LOW WILL DRIVE SLY WINDS TO 25KT THROUGH THE
MORNING HOURS AND WITH DAYTIME WARMING...MIXING WILL BEGIN TO TAP
THE STRONG WINDS ALOFT AND EXPECT SYNOPTIC SCALE WIND GUSTS OF 35 TO
40KT OVER THE ENTIRE CWA IN ADDITION TO ANY LOCALLY HIGHER
THUNDERSTORM GENERATED WIND GUSTS.
BY EARLY EVENING...THE DISCRETE SUPERCELL THREAT SHOULD MORPH INTO A
LINEAR SQUALL LINE MODE. AT THIS TIME...EXPECT THAT THE WRN
PORTIONS OF THE CWA...GENERALLY ALONG AND WEST OF THE I-39 CORRIDOR
WILL HAVE THE GREATEST DISCRETE SUPERCELL POTENTIAL DURING THE
AFTERNOON. THE TRANSITION OVER TO A LINEAR SQUALL LINE MODE SHOULD
OCCUR DURING THE EARLY EVENING HOURS OVER THE CENTRAL PORTIONS OF
THE CWA...GENERALLY BETWEEN I-39 AND I-55...AND THEN STEADILY MARCH
EWD THROUGH THE NIGHT...EXITING THE NWRN INDIANA COUNTIES DURG THE
EARLY MORNING HOURS. WITH THE TRANSITION FROM DISCRETE SUPERCELL TO
LINEAR SQUALL LINE...THE MAIN SEVERE THREAT WILL FOCUS ON STRONG
DAMAGING WINDS. LOCALLY HEAVY RAINFALL MAY ALSO BECOME A CONCERN
OVERNIGHT AS PRECIPITABLE WATER VALUES OVER THE AREA SHOULD BE IN
EXCESS OF 1.5 INCHES AND ANY ECHO TRAINING ALONG THE MAIN CONVECTIVE
LINE COULD LEAD TO LOCALIZED FLASH FLOODING.
BY DAYBREAK MONDAY MORNING...THE MAIN UPPER TROUGH SHOULD PUSH
THROUGH THE UPPER MIDWEST AND GREAT LAKES REGIONS...FORCING THE SFC
COLD FRONT EAST OF THE CWA. THIS SHOULD BRING A QUICK END TO ANY
PCPN POTENTIAL AND MONDAY SHOULD BRING DECREASING CLOUD COVER AND
LITTLE DIURNAL TEMPERATURE SWING THROUGH THE DAY WITH PERSISTENT
COLD ADVECTION SETTING UP BEHIND THE COLD FRONT. TEMPERATURES ON
MONDAY SHOULD ONLY BE IN THE MIDDLE 50S TO MIDDLE 60S. HIGH
PRESSURE WILL QUICKLY BUILD IN OVER MONDAY NIGHT AND
TUESDAY...KEEPING CONDITIONS RELATIVELY COOLER AND DRIER.
FOR THE EXTENDED PERIOD...FROM WEDNESDAY THROUGH SATURDAY...A
RELATIVELY HIGH AMPLITUDE...BUT PROGRESSIVE PATTERN WILL SET UP.
THE NEXT SIGNIFICANT CHANCE FOR PCPN WILL BE ON THURSDAY NIGHT AND
FRIDAY AS A NRN STREAM SHORT WAVE DROPPING OUT OF THE
ROCKIES...LEADING TO STRONG SFC DEVELOPMENT OVER THE CNTRL PLAINS.
THE MAIN SFC LOW SHOULD TRACK THROUGH THE LOCALLY LATE THURSDAY
NIGHT AND FRIDAY...BRINGING THE NEXT CHANCE FOR SHOWERS AND
THUNDERSTORMS TO THE AREA.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* AREA OF SHOWERS/THUNDERSTORMS OVER IA SLIDING EAST ARRIVING ARND
7Z AT TERMINALS.
* ISO IFR CIGS DEVELOPING...OTHERWISE MAINLY LOW END MVFR CIGS.
* STRONG SOUTH WINDS SUN MIDDAY/AFTN...GUSTS UP TO 40 MPH.
BEACHLER
//DISCUSSION...UPDATED 00Z...
VERY DYNAMIC AND POTENT SYSTEM CONTINUES TO DEVELOP. CURRENT
GUIDANCE HAS THE MAIN LOW PRESSURE CENTER WELL TO THE WEST OF
NORTHERN IL/NORTHWEST IN THROUGH THE OVERNIGHT PERIOD...AS A
FRONTAL BOUNDARY CURRENTLY OVER SOUTHERN IL RACES NORTH THIS
EVENING. AS THIS BOUNDARY APPROACHES THE AREA...SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO ACCOMPANY THIS BOUNDARY. GUIDANCE
HAS CORRECTED SLIGHTLY TOWARDS A FOCUS OF 07Z SUN FOR ARRIVAL.
HAVE CONTINUED THIS WITHIN THE CURRENT TAF PKG...AND AS THE
BOUNDARY LIFTS NORTH OVERNIGHT THE BETTER CHC FOR CONVECTION WILL
LIFT NORTH WITH IT AS WELL. THE OTHER ITEM TO NOTE IS THAT
GUIDANCE HAS STEADILY PROGGED A LLVL JET ARND 2KFT AGL OF 40 TO 50
KT DEVELOPING AND LIFTING OVER THE AIRFIELDS OVERNIGHT. HAVE
HANDLED THIS WITH A MENTION OF WS WITHIN THE TAF. THEN SHORTLY AFT
DAYBREAK SUN STRONG SOUTHERLY WINDS WILL MIX DOWN TO THE SFC AND
ERODE THE WS. GUSTS BY SUN AFTN COULD APPROACH 30-35KT AT TIMES.
THE NEXT FOCUS WILL TURN TOWARDS CONVECTION
DEVELOPMENT...TIMING...AND COVERAGE FOR SUN AFTN/EVE. AT THIS TIME
IT APPEARS THUNDER WILL REMAIN OUT OF THE AIRFIELDS UNTIL CLOSER
TO 22 SUN - 00Z MON. HOWEVER...THIS COULD CHANGE QUICKLY DEPENDING
ON THE SPEED AND PLACEMENT OF THE OVERNIGHT THUNDERSTORMS.
THE THIRD CHALLENGE RESIDES WITH HOW LOW CIGS WILL BE. FEEL THE
IFR CIGS ARE STILL PSBL...HOWEVER HAVE A SLIGHTLY LOWER CONFIDENCE
IN THIS. HAVE BACKED OFF TO LOW END MVFR CIGS...AND COULD SEE THIS
FLIRTING WITH IFR CIGS OVERNIGHT. IT WILL ALL HINGE UPON PRECIP
COVERAGE/INTENSITY. THEN WITH BETTER MIXING AFT SUNRISE...CIGS
WILL IMPROVE BACK TO VFR CONDS.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM CONFIDENCE IN WIND FORECAST.
* MEDIUM/HIGH CONFIDENCE IN WS FORECAST.
* LOW CONFIDENCE IN PRECIP TIMING/COVERAGE.
* MEDIUM CONFIDENCE IN CIGS FORECAST.
* LOW CONFIDENCE ON PRECIP/CONVECTION TIMING SUN AFTN/EVE.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...VFR. CHC MVFR W/CHC SHRA EARLY.
TUESDAY...VFR.
WEDNESDAY...VFR. CHC MVFR CIGS W/SHRA ISO TSRA MIDDAY/AFTN.
THURSDAY...VFR. CHC SHRA.
FRIDAY...VFR. CHC SHRA ISO TSRA.
BEACHLER
&&
.MARINE...
257 PM...FORECAST REMAINS ACTIVE THROUGH MONDAY NIGHT WITH SOME
UNCERTAINTY REGARDING HOW HIGH WIND SPEEDS/GUSTS WILL BECOME. LOW
PRESSURE OVER WESTERN ONTARIO WILL MOVE EAST INTO NORTHERN QUEBEC
BY SUNDAY AFTERNOON. A TRAILING FRONTAL BOUNDARY FROM THIS LOW
WILL LIKELY SAG SOUTH ACROSS FAR NORTHERN LAKE MICHIGAN TONIGHT
TURNING WINDS EASTERLY. UNTIL THEN...THE GRADIENT WILL SUPPORT 15
TO 25 KTS ON THE NORTH END OF THE LAKE INTO EARLY THIS EVENING.
MEANWHILE LOW PRESSURE OVER EASTERN COLORADO WILL MOVE NORTHEAST
ACROSS THE PLAINS TONIGHT AND SUNDAY REACHING THE UPPER PENINSULA
OF MICHIGAN BY MONDAY MORNING. THE GRADIENT WILL TIGHTEN AS THIS
LOW APPROACHES. BUT WITH STRONG WARM AIR SPREADING OVER THE COOLER
WATER...CONFIDENCE REGARDING JUST HOW STRONG THE WINDS WILL BECOME
OVER THE OPEN WATERS REMAINS LOW. ITS POSSIBLE THAT THE GRADIENT
MAY BECOME TIGHT ENOUGH FOR LOW END GALES EVEN WITH A LACK OF
MIXING. IF THIS WERE TO OCCUR...THE BEST TIMING WOULD LIKELY BE
SUNDAY EVENING. FOR NOW...HAVE MAINTAINED WINDS TO 30KTS. AND HAVE
ALSO MAINTAINED THE GALE WATCH FOR THE INDIANA/ILLINOIS NEARSHORE
WATERS WITH STRONG WINDS/GUSTS EXPECTED OVER LAND...SPREADING
ACROSS THE NEARSHORE WATERS. AS THE LOW ELONGATES AND LIFTS
NORTHEAST...WINDS WILL SHIFT WESTERLY BY MIDDAY MONDAY AND THEN
NORTHWEST BY MONDAY EVENING. THE GRADIENT APPEARS STRONG ENOUGH
THAT A SHORT PERIOD OF GALES WILL BE POSSIBLE ACROSS NORTHERN LAKE
MICHIGAN MONDAY AFTERNOON. HIGH PRESSURE SPREADS ACROSS THE LAKES
REGION LATE MONDAY NIGHT...CROSSING THE LAKE TUESDAY AFTERNOON
WITH A PERIOD OF LIGHT WINDS EXPECTED...ALONG WITH LAKE BREEZES ON
THE ILLINOIS/INDIANA NEARSHORE WATERS. LOW PRESSURE MOVING ACROSS
THE PLAINS TUESDAY NIGHT INTO WEDNESDAY WILL QUICKLY TIGHTEN A
SOUTHERLY GRADIENT TUESDAY NIGHT INTO WEDNESDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...6 AM SUNDAY TO NOON SUNDAY.
GALE WATCH...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...NOON
SUNDAY TO 10 PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
337 PM CDT SUN APR 15 2012
.SYNOPSIS...
12Z UA ANALYSIS HAS A NEGATIVELY TILTED EXTRATROPICAL CYCLONE OVER
THE PLAINS. 850 AND 700MB WARM AND COLD FRONTS RAN FROM THE UPPER
LOW OVER NEBRASKA INTO SOUTH DAKOTA AND MINNESOTA. THE COLD FRONTS
DROPPED SOUTH FROM THE LOW INTO THE SOUTHERN PLAINS. A LLJ OF 50-70
KNOTS RAIN FROM THE GULF COAST INTO THE GREAT LAKES HELPING TO
TRANSPORT MOISTURE NORTH FROM THE GULF.
18Z SFC ANALYSIS HAS A LOW NEAR KODX WITH A SECONDARY LOW NEAR KYKN.
THE WARM FRONT RAN NORTHEAST INTO SOUTHERN MINNESOTA AND THEN EAST
INTO CENTRAL WISCONSIN. THE COLD FRONT RAN FROM THE KYKN LOW SOUTH
THROUGH THE EASTERN PARTS OF KANSAS...OKLAHOMA...AND TEXAS. A SUBTLE
TROF RAN FROM THE KYKN LOW INTO NORTHEAST MISSOURI. A NARROW BAND OF
60 DEWPOINTS FROM WISCONSIN SOUTH THROUGH ILLINOIS AND THE LOWER
MISSISSIPPI VALLEY. OUTSIDE OF THIS BAND DEW POINTS WERE IN THE 50S.
DEW POINTS IN THE 30S AND 40S WERE ACROSS THE PLAINS.
&&
.SHORT TERM...TONIGHT AND MONDAY
BASED ON CURRENT RUC TRENDS THE BETTER RAIN CHANCES WILL BE ACROSS
THE EASTERN CWFA THIS EVENING. THE WINDOW OF OPPORTUNITY FOR ANY
SEVERE STORMS IS STARTING TO CLOSE. THE SUBSTANTIAL CAP ON THE 18Z
SOUNDING IS THE LIMITING FACTOR. IF THE CAP DOES NOT BREAK BY SUNSET
THEN THE CHANCES FOR ANY SEVERE STORMS WILL RAPIDLY DECREASE.
MOST OF THE PRECIPITATION THIS EVENING WILL BE DONE BY 10 PM EXCEPT
FOR THE FAR EASTERN PARTS OF THE CWFA. WHATEVER CONVECTION IS STILL
PRESENT IN THE CWFA AT 03Z WILL EXIT THE CWFA BY MIDNIGHT. AFTER
MIDNIGHT QUIET ALBEIT WINDY CONDITIONS WILL BE SEEN ACROSS THE AREA.
WRAP AROUND CLOUDS WILL MOVE ACROSS THE CWFA MONDAY MORNING WITH
SOME SHOWERS OVER ROUGHLY THE NORTHERN HALF OF THE CWFA. SKIES WILL
SLOWLY CLEAR DURING THE AFTERNOON HOURS. THE COMBINATION OF CLOUDS
AND PRECIPITATION DURING THE MORNING HOURS WILL HOLD TEMPERATURES TO
BELOW NORMAL.
.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY
THE MODELS HAVE A WEAK DISTURBANCE THAT MOVES THROUGH THE AREA LATE
MONDAY NIGHT/TUESDAY MORNING. SOME MODELS INITIATE PRECIP WITH THIS
FEATURE WHILE OTHERS DO NOT. FOR NOW HAVE OPTED TO KEEP THE SCHC
POPS BUT MOISTURE AVAILABILITY FOR ANYTHING TO DEVELOP IS
QUESTIONABLE. THE FACT THERE IS A WEAK DISTURBANCE MOVING THROUGH
THE AREA INDICATES MORE CLOUDS WILL BE PRESENT WHICH WILL HAVE AN
AFFECT ON TEMPERATURES. HIGH PRESSURE OVER THE AREA WILL RESULT IN
LIGHT WINDS WHICH WILL ALLOW TEMPERATURES TO COOL. FREEZING
TEMPERATURES ARE QUESTIONABLE BUT SOME PATCHY FROST MIGHT OCCUR IN
AND IMMEDIATELY SOUTH OF THE HWY 20 CORRIDOR.
AFTER A QUIET TUESDAY AFTERNOON/EVENING THE NEXT SYSTEM APPROACHES
THE AREA FROM THE PLAINS. MODELS SHOW THIS SYSTEM TO BE MORE
VIGOROUS SO THE CHANCES FOR PRECIPITATION SHOULD BE BETTER. THUS THE
SCHC/CHC POPS AFTER MIDNIGHT LOOK REASONABLE GIVEN THE TIMING.
ON WEDNESDAY THIS SYSTEM WILL MOVE ACROSS THE AREA BRINGING ANOTHER
CHANCE OF RAIN. POPS HAVE BEEN INCREASED TO HIGH CHC OVER MOST OF
THE AREA BUT MAY NEED TO BE INCREASED FURTHER TO LIKELY IF CURRENT
TRENDS WITH THE MODELS CONTINUE.
WEDNESDAY NIGHT ON...
MODEL CONSENSUS MAINTAINS AN ACTIVE NORTHWEST FLOW WITH SEVERAL
DISTURBANCES MOVING THROUGH IT. THE INITIAL WAVE ON WEDNESDAY EXITS
THE AREA WED EVENING SO THE SCHC/CHC POPS LOOK REASONABLE. MODELS
CONTINUE TO DISAGREE ON POSITION AND TIMING BUT ANOTHER STORM SYSTEM
WILL MOVE THROUGH THE AREA IN THE THURSDAY THROUGH FRIDAY EVENING
TIME PERIOD. CONSENSUS GIVES MAINLY CHC POPS WITH THE HIGHEST POPS
CENTERED ON THURSDAY NIGHT.
CONSENSUS HAS A WEAK DISTURBANCE MOVING THROUGH THE AREA ON
SATURDAY. MOISTURE IS QUESTIONABLE RIGHT NOW SO THE SCHC POPS BY THE
CONSENSUS LOOKS REASONABLE. RIGHT NOW SUNDAY LOOKS DRY WITH HIGH
PRESSURE MOVING THROUGH THE AREA. ..08..
&&
.AVIATION... /ISSUED 1234 PM CDT SUN APR 15 2012/
VERY WINDY WEATHER WITH SCATTERED STRONG TO SEVERE THUNDERSTORMS
ARE EXPECTED AT ALL EASTERN IOWA AND ILLINOIS TAF SITES TODAY.
SOUTH WINDS WILL INCREASE TO 20 TO 30 KTS...GUSTING 35 TO 40 KTS
IN THE NEXT COUPLE HOURS...AND WILL CONTINUE THROUGH 02Z
TONIGHT...BEFORE DIMINISHING TO AROUND 15 TO 25 KTS SOUTHWEST
AFTER 08Z/16. A COLD FRONT WILL MOVE THROUGH GENERALLY AROUND
12Z/16TH...SWITCHING WINDS TO NORTHWEST SUSTAINED 15 TO 20 KTS
WITH GUSTS TO 25KTS. VARIABLE VFR TO MVFR WEATHER WILL CONTINUE
NEAR THUNDERSTORMS TODAY...AND EARLY THIS EVENING...WITH GENERALLY
VFR WEATHER OTHERWISE. ..LE..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR BENTON-BUCHANAN-
CEDAR-CLINTON-DELAWARE-DES MOINES-DUBUQUE-HENRY IA-IOWA-
JACKSON-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-
MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR BUREAU-CARROLL-
HANCOCK-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-MERCER-
PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE.
MO...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR CLARK-SCOTLAND.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1210 AM CDT SUN APR 15 2012
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
STRONG-SEVERE THUNDERSTORMS WILL BE IN THE VICINITY OF KSLN AND
MOVING INTO KHUT/KICT SHORTLY AFTER START OF FORECAST. DRYLINE WILL
BE MOVING ACROSS MOST OF THE AREA THROUGH DAYBREAK. IFR
CONDITIONS...HAIL AND 50KT+ WINDS WILL BE BRIEFLY POSSIBLE WITH
ANY OF THE SEVERE STORMS. VERY GUSTY SOUTHWEST WINDS ANTICIPATED
BEHIND DRYLINE. SOME VFR CLOUDS IN WRAP AROUND POSSIBLE AT
KRSL/KSLN SUN AFTERNOON. -HOWERTON
&&
.PREV DISCUSSION... /ISSUED 632 PM CDT SAT APR 14 2012/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
CONVECTIVE TRENDS WILL BE THE MAIN ISSUE...WITH STRONG-SEVERE
THUNDERSTORMS IN THE VICINITY OF KSLN AND NOT TOO FAR FROM KHUT AT
START OF FORECAST. WILL CONTINUE WITH VCTS AT KRSL/KICT...AS
TIMING OF STORMS IS A BIT UNCLEAR AND IMPACT IF INCLUDED WOULD BE
SIGNIFICANT. 00-06 UTC WILL LIKELY BE THE MOST ACTIVE AT
KHUT/KICT/KSLN. WITH DRYLINE REMAINING WELL WEST OF THE
AREA...STORMS MAY CONTINUE TO REGENERATE THROUGHOUT THE EVENING. IFR
CONDITIONS...LARGE HAIL AND 50KT+ WINDS WILL BE BRIEFLY POSSIBLE
WITH ANY OF THE SEVERE STORMS. ANTICIPATE DRYLINE SHOULD ENTER THE
AREA AROUND 0700 UTC AND NOT EXIT SOUTHEAST KS UNTIL AFTER 1200
UTC. VERY GUSTY SOUTHWEST WINDS ANTICIPATED BEHIND DRYLINE.
-HOWERTON
PREV DISCUSSION... /ISSUED 333 PM CDT SAT APR 14 2012/
DISCUSSION...
MAIN FORECAST CONCERN: THIS EVENING AND TONIGHT WILL BE THE MOST
CONCERNING PORTION OF THE FORECAST WITH AMPLIFIED SEVERE THREAT FOR
THE COUNTY WARNING AREA. OTHERWISE...THE ISSUES INCLUDE THE POPS FOR
SUNDAY INTO MONDAY WITH THE LOW PUSHING OUT OF THE AREA AND ANY
POTENTIAL WRAP AROUND.
TONIGHT:
DRYLINE WILL BE EVEN SLOWER TO MOVE ACROSS THE AREA...MOST LIKELY
LATER TONIGHT. HOWEVER CONSIDERABLE INSTABILITY/SHEAR ALREADY IN
PLACE...WITH ISOLATED SEVERE STORMS JUST WEST OF AREA AT THIS
TIME. BELIEVE CONDITIONS ARE SUFFICIENT FOR THESE TO CONTINUE AS
THEY MOVE EAST...WITH WITH SOUTHERN SECTIONS LIKELY HAVING BETTER
INSTABILITY THROUGH SUNSET. GIVEN HODOGRAPHS...SUPERCELLS WITH
TORNADIC POTENTIAL WILL EXIST...WELL INTO THE EVENING. DRYLINE
SHOULD SWEEP ACROSS THE AREA DURING MIDDLE OF THE NIGHT.
TEMPERATURES WILL LIKELY REMAIN QUASI STEADY AHEAD OF THE DRYLINE
GIVEN THE LOW LEVEL MOISTURE AND GRADIENT WINDS. -HOWERTON
SUNDAY:
BETTER ALIGNMENT OF THE SURFACE AND UPPER LEVEL TROUGH WHICH WILL
CONTINUE TO PUSH OFF TO THE NORTHEAST ON SUNDAY. A COLD FRONT WITH
THIS SYSTEM IS ANTICIPATED TO SLIDE THROUGH CENTRAL KANSAS FIRST
THEN THROUGH THE REST OF SOUTH CENTRAL AND SOUTHEAST KANSAS THROUGH
THE DAY. THERE IS CONCERN OF STRONG WINDS AHEAD OF AND BEHIND
FRONTAL PASSAGE WITH SUSTAINED SPEEDS JUST SHY OF WIND ADVISORY
CRITERIA BASED ON CURRENT TRENDS. DECIDED AGAINST ISSUING ANY WIND
HEADLINES RIGHT NOW...BUT THE NEXT FORECAST MAY DECIDE TO GO FORWARD
WITH IT. THERE MAY BE LINGERING SHOWERS AND THUNDERSTORMS WITH THE
EXITING LOW WHICH WILL CONTINUE INTO THE MORNING AND AFTERNOON HOURS
IN SOUTHEAST KANSAS...BUT SEVERE POTENTIAL DOES NOT APPEAR TO BE
HIGH WITH THE MAJOR SOURCES OF INSTABILITY DIMINISHING. DID DECREASE
THE POPS SUNDAY EVENING AND NIGHT AS THE PROGRESSION OF THE SYSTEM
APPEARS TO BE MUCH QUICKER THAN PREVIOUSLY ANTICIPATED.
MONDAY:
A SECONDARY WAVE APPEARS TO BE ASSOCIATED WITH THE UPPER LEVEL AT
500MB THAT WILL SLIDE THROUGH ON MONDAY...YET HIGH PRESSURE AT THE
SURFACE TO 850MB. THERE MAY BE A FEW SHOWERS ASSOCIATED WITH THIS
WAVE PARTICULARLY IN CENTRAL AND POTENTIALLY SOUTH CENTRAL KANSAS.
PV DOES INDICATE A PIECE ENERGY MOVING WITH THIS SYSTEM...HOWEVER
MODELS VARY IN LOCATION AND DEVELOPMENT OF ANY PRECIPITATION. THUS
DECIDED TO WAIT ON CHANCES FOR NOW.
TUESDAY TO SATURDAY:
THE NEXT TROUGH WILL START TO DO MOST OF ITS DEVELOPMENT WHEN IT
MOVES OVER THE ROCKIES FOR WEDNESDAY TO THURSDAY...HOWEVER 850MB
INDICATES THE MAIN SYSTEM TO STAY IN THE NORTHERN PLAINS. AT THE
SURFACE...THERE IS INDICATION OF THE LOW PASSING THROUGH ON THURSDAY
WITH SOME ASSOCIATED INSTABILITY FOR THE AFTERNOON AND EVENING
HOURS. THUS KEPT THUNDERSTORM CHANCES IN FOR THIS TIME FRAME.
MOVEMENT OF THIS NEXT TROUGH IN THIS EXTENDED IS A BIT QUESTIONABLE
WITH MODEL VARIATION IN THE TIMING...DEPTH AND EXACT LOCATION. THIS
COULD CHANGE ANY POTENTIAL IN POPS. TEMPERATURES ARE ON TRACK TO
CLIMB TO NEAR TO ABOVE NORMAL WITH THURSDAY LOOKING TO BE THE
WARMEST DAY OF THE WEEK WITH THE GOOD SURGE OF WARM AIR ADVECTION
OUT AHEAD OF THE NEXT SYSTEM.
VP
PREV DISCUSSION... /ISSUED 242 PM CDT SAT APR 14 2012/
UPDATE...
12 UTC AND LATER RUC MODEL RUNS SUGGEST DRYLINE WILL BE EVEN SLOWER
TO MOVE ACROSS THE AREA...MOST LIKELY LATER TONIGHT. THIS WILL
IMPACT SEVERE THREAT ACROSS THE AREA. AT THIS TIME...BEST
INSTABILITY/WEAKEST CAP IS OCCURRING ACROSS WESTERN SECTIONS OF
CENTRAL KS WITH CAP HOLDING ON ACROSS MOST OF SOUTH CENTRAL/
SOUTHEAST KS. GIVEN LACK OF SURFACE BOUNDARY AND EXTENSIVE CLOUDS
SO FAR...MAY BE TOUGH TO BREAK CAP ACROSS SOUTH CENTRAL KS THIS
AFTERNOON. HOWEVER A FEW SMALL BREAKS IN CLOUDS ARE EVIDENT IN
VISIBILITY SATELLITE SOUTH/WEST OF ICT. IF STORMS CAN DEVELOP IN
THIS AREA...CLEARLY ENVIRONMENT WOULD BE CONDUCIVE FOR STRONG/
SEVERE STORMS. BIGGEST THREAT TONIGHT IS ROUGHLY ALONG AND SOUTH
OF HIGHWAY 400 ACROSS SOUTH CENTRAL KS...EAST TO HIGHWAY 99 IN
THE 00-04 UTC TIME FRAME...WITH INCREASING ELEVATED STORM RISK
03-06 UTC ACROSS CENTRAL KS EAST OF I-135. -HOWERTON
AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
CONVECTIVE TRENDS WILL BE THE MAIN ISSUE...WITH STRONG-SEVERE
THUNDERSTORMS IN THE VICINITY OF KRSL AT START. ISOLATED-SCATTERED
RAIN SHOWERS/THUNDERSTORMS WILL BE POSSIBLE DURING THE AFTERNOON AT
KSLN/KHUT/KICT...BUT EXPECT COVERAGE/INTENSITY TO RAMP UP TOWARDS
0000 UTC...WITH 0000 UTC-06 UTC THE MOST ACTIVE AT KHUT/KICT/KSLN.
IFR CONDITIONS...LARGE HAIL AND 50KT+ WINDS WILL BE BRIEFLY
POSSIBLE WITH ANY OF THE SEVERE STORMS. DRYLINE SHOULD ENTER THE
AREA LATER TONIGHT...BRINGING END TO PRECIPITATION AND LOSS OF
CEILING. GUSTY SOUTHWEST WINDS ANTICIPATED BEHIND DRYLINE.
-HOWERTON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 44 66 45 71 / 0 10 10 0
HUTCHINSON 44 66 42 70 / 0 10 10 0
NEWTON 45 65 42 70 / 10 10 10 0
ELDORADO 45 67 43 71 / 10 10 10 0
WINFIELD-KWLD 45 69 46 72 / 10 10 0 0
RUSSELL 39 64 41 71 / 10 20 10 10
GREAT BEND 39 64 42 70 / 10 20 10 0
SALINA 43 65 41 70 / 10 20 10 10
MCPHERSON 44 65 41 70 / 10 10 10 10
COFFEYVILLE 47 68 44 71 / 10 10 10 0
CHANUTE 47 67 42 70 / 10 10 10 0
IOLA 47 66 42 69 / 10 10 10 0
PARSONS-KPPF 47 68 44 70 / 10 10 10 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS JACKSON KY
906 PM EDT MON APR 16 2012
.UPDATE...
ISSUED AT 906 PM EDT MON APR 16 2012
SHOWERS AND TSTORMS THAT DEVELOPED ALONG THE FRONT ARE NOW EXITING
OUR VA BORDER COUNTIES. THE PAST COUPLE RUNS OF THE HRRR BRING
ANOTHER AREA OF SHOWERS NORTHEAST FROM NORTHERN ALABAMA INTO FAR
SOUTHEAST KENTUCKY TOWARDS DAWN SO WILL LINGER A 20 POP OVERNIGHT
INTO EARLY TUESDAY MORNING FOR BELL AND HARLAN COUNTIES. THE REST OF
THE AREA SHOULD REMAIN DRY. THE REMAINDER OF THE FORECAST LOOKS ON
TRACK WITH JUST SOME FINE TUNING OF SKY/TEMPS/DEWS NEEDED. HAVE A
GOOD NIGHT.
UPDATE ISSUED AT 523 PM EDT MON APR 16 2012
ILL DEFINED COLD FRONT IS WORKING ACROSS THE AREA WITH ANOTHER TROUGH
EVIDENT BY A WIND SHIFT ENTERING NORTH CENTRAL KENTUCKY AT THIS TIME.
RADAR RETURNS NEAR LAKE CUMBERLAND ARE LIKELY VIRGA AND ANY
ADDITIONAL SHOWER ACTIVITY THIS EVENING SHOULD BE ISOLATED AT BEST
AND HAVE TRIMMED BACK NEAR TERM POPS TO FIT THAT SCENARIO.
OTHERWISE...HAVE JUST PROVIDED SOME TWEAKS TO TEMPS/DEWPOINTS/SKY
COVER/WINDS TO FIT CURRENT AND EXPECTED NEAR TERM CONDITIONS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 215 PM EDT MON APR 16 2012
WAVE OF SHRA CROSSING ERN KY THIS AFTERNOON. PROJECTING THE TRAILING
EDGE OF THE PCPN HAS IT JUST EAST OF THE STATE BY 8 PM. THIS IS WELL
REFLECTED IN NEARLY ALL THE MODELS. CLOUD COVER EXTENDS FROM MI TO TX
SO CLEARING WILL TAKE A WHILE TONIGHT AND WILL KEEP CONSIDERABLE
CLOUDS IN FCST THRU THE OVERNIGHT PERIOD TONIGHT. COOLER AIR WILL
THEN CYCLE BACK INTO THE AREA FOR TUE AS TEMPS BEHIND THE FRONT ARE
10-15 DEG COOLER THAN PRE FRONTAL. EXPECTING HIGHS ON TUE ONLY TO
REACH THE MID 60S. THE CURRENT FRONT WILL STALL TO OUR SOUTH
THRU TUE AND THEN A WAVE IN THE GULF WILL SLIDE EAST AND WAVE THE
BOUNDARY BACK TO THE NORTH LATE TUE NIGHT WITH CHANCE POPS IN OUR
SERN COUNTIES. THE CHANCE OF RAIN DROPS OFF QUICKLY AS YOU HEAD NORTH
AND THE BLUEGRASS COUNTIES IN OUR NORTHERN FCST AREA SHOULD BE RAIN
FREE. THE CLOUD COVER THAT ACCOMPANIES THE RAIN TUE NIGHT WILL KEEP
OVERNIGHT LOWS A BIT WARMER IN THE SOUTH. THE PARTLY CLOUDY SKIES AND
LIGHT WINDS TUE NIGHT WILL ALLOW TEMPS TO DROP INTO THE UPPER 40S
SOUTH AND MID 40S NORTH...WHICH IS ABOUT NORMAL FOR THIS TIME OF THE
YEAR.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 300 PM EDT MON APR 16 2012
THE EXTENDED FORECAST PERIOD BEGINS ON WEDNESDAY WITH A PROGRESSIVE
MOSTLY ZONAL PATTERN IN PLACE. A DEVELOPING SHORTWAVE LOCATED OVER
THE SOUTHEAST EXITS THE EAST COAST BY WEDNESDAY NIGHT. AT THE
SURFACE...DURING THE DAY WEDNESDAY...A LOW DEVELOPS AND MOVES NE OFF
THE EAST COAST. EASTERN KENTUCKY WILL STILL STAND TO RECEIVE SOME
DEFORMATION PRECIP ON THE BACK EDGE OF THE SYSTEM AS IT EXITS OFF TO
THE NORTHEAST. WEAK RIDGING THEN WILL KEEP EASTERN KENTUCKY DRY FOR
THE THURSDAY THROUGH FRIDAY NIGHT TIME FRAME. BY FRIDAY NIGHT...THE
UPPER LEVEL PATTERN GAINS SOME AMPLITUDE AND BECOMES MERIDIONAL AS BY
SATURDAY...A TROUGH DIGS INTO THE SOUTH CENTRAL PLAINS WHILE RIDGING
BUILDS IN THE SOUTHWEST AND OFF THE EAST COAST. BY LATE
SATURDAY...SURFACE LOW PRESSURE REDEVELOPS ALONG A NEARLY STALLED
BOUNDARY DRAPED FROM THE LOWER MS VALLEY NORTHEAST INTO THE OH
VALLEY. THE SYSTEM STRENGTHENS AS IT BEGINS TO MOVE UP THE EAST
COAST. BOTH THE EURO AND GFS PAINT THIS SIMILAR SCENARIO.
AFTER RUNNING THE INITIALIZATION...HAD TO TRIM BACK POPS FOR THE
APPROACHING FRONT FRIDAY NIGHT. THE DEVELOPING AMPLITUDE OF THE
PATTERN WOULD SUGGEST A SLOWING TO THE APPROACH OF THE FRONT AND THE
12Z GFS AND 00Z EURO AGREE TO THIS SO BROUGHT THE BULK OF THE POPS
INTO THE AREA BY 12Z SATURDAY. WITH BOTH THE GFS AND THE EURO CLOSING
OFF THE UPPER LOW OVER THE EAST TOWARD THE END OF THE PERIOD AND THE
SURFACE LOW TRANSITIONING TO A COASTAL LOW TYPE SET UP...KEPT POPS IN
THE FORECAST FOR THE REST OF THE EXTENDED. OTHERWISE...ANY OTHER
ADJUSTMENTS WERE FOR TERRAIN AND MATCHING UP WITH NEIGHBORING
OFFICES.
WITH THE SOUTHERLY FLOW AHEAD OF THE LOW FOR THE FIRST FEW DAY OF
THE EXTENDED...HIGHS WILL BE AROUND IF NOT A LITTLE ABOVE NORMAL. BY
DAYS 6 AND 7...TEMPERATURES WILL DROP BY 5 TO 10 DEGREES BELOW NORMAL
AS AT THIS POINT...MODELS ARE INDICATING QUITE A BIT OF COLDER AIR
BEHIND THIS SYSTEM.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 718 PM EDT MON APR 16 2012
A COLD FRONT WILL STALL OUT TO OUR SOUTHEAST OVER THE NEXT 24 HOURS.
A WAVE OF LOW PRESSURE WILL FORM AND MOVE ALONG THIS FRONT ON
TUESDAY KEEPING CLOUDS RATHER PROLIFIC DURING THE PERIOD...ALTHOUGH
CIGS WILL BE VFR. AFTER THE ISOLATED SHOWERS AFFECTING 1A6 NOW MOVE
EAST THIS EVENING...NO PRECIP IS EXPECTED ACROSS EAST KENTUCKY UNTIL
AFTER 00Z TUESDAY EVENING. WINDS WILL DROP OFF AFTER SUNSET...AND
SPEND THE REST OF THIS TAF PERIOD BELOW 10 KTS FROM A NORTH TO
NORTHEASTERLY DIRECTION.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ABE
SHORT TERM...DUSTY
LONG TERM....SHALLENBERGER
AVIATION...ABE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
708 PM EDT MON APR 16 2012
.SYNOPSIS...
ISSUED AT 408 PM EDT MON APR 16 2012
WINDY CONDITIONS WILL CONTINUE INTO THE EVENING HOURS BEFORE
SUBSIDING AFTER DARK. HIGH WINDS CAN BE EXPECTED THROUGH 800 PM OR
SO. SCATTERED RAIN SHOWERS THIS EVENING WILL MIX WITH SOME SNOW
BEFORE ENDING TOWARDS MIDNIGHT. OVERNIGHT CLOUDS WILL DECREASE AS
WILL THE WINDS SETTING THE STAGE FOR ANOTHER ROUND OF FROST AND
FREEZING TEMPERATURES LATE. A DRY AND COOL DAY IS EXPECTED ON
TUESDAY...BEFORE RAIN RETURNS TO THE FORECAST FOR
WEDNESDAY...THURSDAY AND FRIDAY. THE RAIN WILL BE ASSOCIATED WITH
A FRONTAL BOUNDARY THAT LINGERS IN THE REGION.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 408 PM EDT MON APR 16 2012
MAIN CONCERNS IN THE SHORT TERM PERTAIN TO HEADLINES. NAMELY...THE
WIND ADVISORY THAT IS OUT THROUGH 1000PM AND FROST AND FREEZE
HEADLINES.
REGARDING THE WIND ADVISORY...MAINTAINED IT AS IS...COVERING THE
ENTIRE FORECAST AREA THROUGH 1000PM. LATEST HRRR MODEL CONTINUES
TO INDICATE THE EXPIRATION TIME LOOKS GOOD. STRONG WINDS CONTINUE
THROUGH 800 PM OR SO...THEN DIMINISH STEADILY THEREAFTER. SOLID
PUSH OF COLD AIR ADVECTION IS NOW COMING ACROSS THE LAKE AND
EXPECT STRONG WINDS IN THE COLD AIR ADVECTION TO CONTINUE. GUSTS
OF 45 TO 55 MPH SHOULD CONTINUE THROUGH SUNSET.
WILL BE ISSUING A FREEZE WARNING FOR THE NORTHERN HALF OF THE
FORECAST AREA...MUSKEGON...NEWAYGO...MONTCALM AND CLINTON COUNTIES
NORTHWARD. A FROST ADVISORY FOR OTTAWA...KENT...IONIA AND INGHAM
COUNTIES SOUTHWARD. CLOUDS WILL SCATTER OUT OVERNIGHT AND WINDS
WILL DIMINISH CONSIDERABLY AFTER 06Z. THE COLD AIR ADVECTION ONLY
WILL DRIVE TEMPERATURES TO LEVELS THAT WILL BE A CONCERN TO TENDER
VEGETATION. EXPECTING UPPER 20S FOR LOWS TO THE NORTH AND LOWER
30S TO THE SOUTH.
OTHERWISE...QUIET WEATHER ON TUESDAY WITH SURFACE RIDGING SLIDING
ACROSS THE LOWER PENINSULA. INCREASING CLOUDS ARE EXPECTED TUESDAY
NIGHT AHEAD OF A SHORTWAVE SLIDING EAST IN ZONAL FLOW. KEPT THE
FORECAST DRY AS THE PRECIP SHOULD HOLD OFF INTO WEDNESDAY. ANOTHER
FROST/FREEZE POTENTIAL TUESDAY NIGHT...BUT AN INCREASE WIND AND
CLOUD COVER MAY END THE THREAT. LATER FORECASTS WILL LOOK INTO
THIS THREAT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 408 PM EDT MON APR 16 2012
PROGRESSIVE FLOW WILL BRING ANOTHER NORTHERN STREAM WAVE INTO THE
REGION WED/WED NIGHT. MODEL TRENDS ARE A BIT FASTER...SO HAVE ADDED
POPS TO THE EASTERN CWA LATE WED...THEN REMOVED POPS FOR LATE WED
NIGHT IN THE NW CWA. COULD BE A FEW ISOLATED THUNDERSTORMS WITH
SOME WEAK INSTABILITY.
THE FRONT STALLS JUST TO OUR SOUTH WITH A WAVE OF LOW PRESSURE
TRACKING ALONG IT. THE MODELS ARE TRENDING FURTHER NORTH WITH THIS
LOW...THE GFS COMING MORE IN LINE WITH THE EURO. SO THE SHOWERS
SHOULD RETURN/LINGER INTO THURSDAY/THURSDAY NIGHT. COLD ENOUGH AIR
MAY FILTER IN BEHIND THE LOW...WHERE RAIN COULD MIX WITH SOME SNOW
LATE FRIDAY INTO FRIDAY NIGHT. BUT BY THIS TIME FRAME THE PCPN
SHOULD BE RATHER LIGHT.
THE WEEKEND CONTINUES TO LOOK DRY BUT COOL AS THE PATTERN BECOMES
BLOCKED. THE LOW TO OUR EAST STALLS AND MAY EVEN RETROGRADE A BIT
INTO THE FIRST PART OF NEXT WEEK. HAVE PUT LOW POPS IN FOR THE FAR
SE CWA FOR MON.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 708 PM EDT MON APR 16 2012
GUSTY WESTERLY WINDS UP TO 30 KNOTES EXPECTED THROUGH AROUND 03Z
TUESDAY BEFORE WINDS DIMINISH. LOW VFR CLOUD DECK TO HANG ON
THOUGH AROUND 03Z TUESDAY AS WELL...BEFORE SKIES CLEAR. VFR
CONDITIONS EXPECTED THROUGH THE PERIOD.
&&
.MARINE...
ISSUED AT 408 PM EDT MON APR 16 2012
MAINTAINED THE GALE WARNING THROUGH 1000 PM AS SOME OF THE
STRONGER WINDS IN COLD AIR ADVECTION ARE MOVING OUT OVER THE LAKE
AT THIS TIME. LOOKING FOR GALES TO CONTINUE THROUGH THE EARLY
EVENING HOURS...BEFORE SLOWLY SUBSIDING AROUND 1000 PM. A SMALL
CRAFT ADVISORY WILL BE NEEDED FOR THE RESIDUAL WAVE FIELD AFTER
THE GALES DIE DOWN. MOST LIKELY A SCA THROUGH THE REST OF THE
NIGHT WILL COVER IT. LIGHT WINDS ARE EXPECTED FOR TUESDAY INTO
TUESDAY NIGHT. SOUTHERLY WINDS RAMP UP AGAIN ON WEDNESDAY.
&&
.HYDROLOGY...
ISSUED AT 408 PM EDT MON APR 16 2012
RAINFALL OVER THE WEEKEND REACHED THE 1.00 TO 2.00 INCH RANGE IN
MANY LOCATIONS. THE HIGHEST TOTAL OCCURRED AT THE SOUTH HAVEN
WATER INTAKE PLANT WHERE 3.02 INCHES OF RAIN WAS MEASURED. THE
HEAVIEST RAINS WERE NOTED ACROSS THE WEST AND SOUTHWEST PORTIONS
OF THE FORECAST AFFECTING THE KALAMAZOO AND ST. JOSEPH RIVER
BASINS THE MOST. AT THIS POINT...RIVERS ARE SHOWING WITHIN BANK
RISES...BUT NO ADVISORIES AND WARNINGS HAVE BEEN ISSUED.
NOT EXPECTING MUCH IN THE WAY OF ADVISORIES OR WARNINGS BASED ON
HOW THE RAIN FELL. IN ADDITION WE ARE LOOKING AT MAINLY DRY
WEATHER THROUGH TUESDAY NIGHT. RAINFALL WITH A FRONT ON WEDNESDAY
SHOULD BE FAIRLY LIGHT AS WELL. RIVERS SHOULD BE ABLE TO STAY
WITHIN BANK OR RECEDE THROUGH MID WEEK AT MOST LOCATIONS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FROST ADVISORY FROM 2 AM TO 9 AM EDT TUESDAY FOR MIZ056>059-
064>067-071>074.
WIND ADVISORY UNTIL 10 PM EDT THIS EVENING FOR MIZ037>040-
043>046-050>052-056>059-064>067-071>074.
FREEZE WARNING FROM 2 AM TO 9 AM EDT TUESDAY FOR MIZ037>040-
043>046-050>052.
LM...GALE WARNING UNTIL 10 PM EDT THIS EVENING FOR LMZ844>849.
&&
$$
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...JK
AVIATION...JMM
HYDROLOGY...DUKE
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
449 PM EDT SUN APR 15 2012
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 446 PM EDT SUN APR 15 2012
SHORT TERM FCST HAS BEEN A CHALLENGE TODAY WITH IMPORTANT DETAILS TO
CAPTURE IN THE GRIDS WITH NEARLY ALL FCST ELEMENTS... INCLUDING
SIGNIFICANT NON-DIURNAL TEMPS TRENDS...GALES ON THE LAKE/POSSIBLE
ADVY WINDS INLAND...POSSIBLE SVR TSRA TONIGHT...AND MIX PCPN ISSUES
MON.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS SHORTWAVE
LIFTING NE THRU THE WRN PLAINS. SFC LOW IS OVER NE NEBRASKA WITH SFC
WARM FRONT EXTENDING NE TO NEAR KMSP THAN E TO JUST N OF KGRB. FRONT
HAS MADE LITTLE PROGRESS OVER THE LAST FEW HRS...AND SO FAR...THERE
HASN`T BEEN MUCH SHRA ACTIVITY N OF THE FRONT. STRONGER LOW-MIDLEVEL
FRONTOGENESIS IS SUPPORTING BEST SHRA DEVELOPMENT TO THE W IN NE
MN/WRN LAKE SUPERIOR. HOWEVER...WITH MODELS INDICATING MOISTURE
TRANSPORT BECOMING FOCUSED TOWARD UPPER MI OVER THE NEXT FEW HRS...
SHRA SHOULD EXPAND OVER THE FCST AREA. WITH ELEVATED CAPE ALSO
INCREASING...ISOLD/SCT TSRA SHOULD ALSO DEVELOP. SVR THREAT IS
UNCERTAIN TONIGHT DUE TO UNCERTAINTY IN PROGRESS OF WARM FRONT. IF
FRONT LINGERS TO S THIS EVENING AND ELEVATED STORMS DO DEVELOP...
EFFECTIVE SHEAR WILL SUPPORT ORGANIZED UPDRAFTS AND A HAIL
POTENTIAL...ESPECIALLY OVER THE SCNTRL. IF WARM FRONT LIFTS N THRU
CNTRL/ERN UPPER MI...THERE MAY NOT BE MUCH ACTIVITY UNTIL COLD FRONT
ARRIVES LATE TONIGHT WHEN INSTABILITY WILL BE DIMINISHING. AT THIS
POINT...ELEVATED SVR STORMS APPEAR THE MORE LIKELY SCENARIO IF
STORMS CAN ORGANIZE N OF SLOW MOVING WARM FRONT. TEMPS TONIGHT WILL
ALSO BE HIGHLY DEPENDENT ON WARM FRONT LOCATION. TEMPS MAY RISE
ACROSS THE CNTRL/E WHILE A CHILLY E WIND KEEPS READINGS OVER THE
KEWEENAW IN THE LWR 40S. FOG MAY BE DENSE AT TIMES WHERE FLOW IS
UPSLOPE OFF LAKE SUPERIOR AND LAKE MICHIGAN.
SFC LOW WILL TRACK ACROSS CNTRL UPPER MI/SE LAKE SUPERIOR LATE
TONIGHT/MON MORNING. SHARP/STRONG CAA MON WILL BRING A QUICK DROP IN
TEMPS FROM NW TO SE AFTER COLD FROPA. FCST SOUNDINGS SUGGEST AT
LEAST SOME POTENTIAL FOR A BRIEF PERIOD OF SLEET BTWN THE TRANSITION
FROM RAIN TO SNOW. LOW-LEVEL TEMPS ALSO APPEAR TO FALL ENOUGH FOR
SOME LAKE ENHANCEMENT IN THE DEFORMATION PCPN AREA SWINGING ACROSS
UPPER MI MON. RIGHT NOW...EXPECT 1 TO 2 INCHES OF SNOW MON OVER THE
W AND NCNTRL. HIGH TERRAIN OF THE FAR W MAY SEE UP TO 3 INCHES.
COULD BE A SNOW ADVY EVENT IF DEFORMATION PCPN SHIELD BECOMES WELL
ORGANIZED TO THE W TONIGHT. AS FOR WINDS...SHARP CAA WILL ENHANCE
LOW-LEVEL MIXING...AND WITH 40-45KT AVBL IN THE MIXED LAYER...ADVY
LEVEL WINDS ARE A GOOD BET NEAR LAKE SUPERIOR MON...ESPECIALLY
KEWEENAW COUNTY BEGINNING IN THE MORNING AND FROM KMQT EASTWARD IN
THE AFTN. ISALLOBARIC COMPONENT TO THE WIND ROUGHLY 90 DEGREES TO
THE GRADIENT WIND SHOULD KEEP THIS FROM BEING A HIGHER END WIND
EVENT. TEMPS WILL FALL FROM NW TO SE THRU THE DAY...THOUGH THERE
WILL BE SOME WARMING OVER THE E MON MORNING PRIOR TO COLD FROPA.
TEMPS IN THE AFTN WILL PROBABLY BE AT OR BELOW FREEZING OVER THE W
AND NCNTRL.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 446 PM EDT SUN APR 15 2012
NO SIGNIFICANT CHANGES TO UPPER PATTERN DEPICTION SHOWN BY MEDIUM
RANGE MODELS YDY WITH NEGATIVE ANAMOLIES STATIONED OVER NORTHEAST
PACIFIC OCEAN/GULF OF ALASKA AND OVR HUDSON BAY INTO NUNAVUT CANADA.
ZONAL FLOW DOMINATES CONUS MUCH OF THE WEEK AND REALLY INTO NEXT
WEEKEND AS WELL. ATTM ONLY ONE SYSTEM WILL IMPACT THE AREA IN THE
LONGER TERM...BUT THAT MAY CHANGE DEPENDING ON TRACK OF LATE WEEK
SYSTEM.
BLAST OF WINTRY WEATHER GRADUALLY DIMINISHES ON MONDAY NIGHT. PLENTY
OF 925-850MB MOISTURE...CYCLONIC SFC-H85 FLOW...AND 900 TEMPS AROUND
-10C SO PREFER TO LET SNOW SHOWERS LINGER ALONG LK SUPERIOR INTO THE
OVERNIGHT HOURS FOR AREAS FAVORED BY NW WINDS. ADDITIONAL SNOW
ACCUMS MONDAY NIGHT WILL STILL BE MINIMAL. MAIN ISSUE WILL BE GUSTY
NORTH-NORTHWEST WINDS UP TO 45 MPH ALONG LK SUPERIOR ALONG WITH THE
SNOW SHOWERS. ARRIVAL OF LOW-LEVEL RIDGE DIMINISHES SNOW SHOWERS
TOWARD MORNING OVER EASTERN CWA. SFC RIDGE AND EDGE OF THERMAL TROUGH
RESULTS IN LIGHT WINDS/COOL CONDITIONS ON TUESDAY. COOLEST READINGS
AROUND 40 DEGREES ALONG LK SUPERIOR WITH NE WINDS.
SHORTWAVE ON SOUTHERN EDGE OF TROUGH OVR GULF OF ALASKA FCST TO
SLIDE ACROSS ROCKIES INTO NORTHERN PLAINS BY TUESDAY NIGHT AND PUSH
ACROSS UPPER GREAT LAKES ON WEDNESDAY. SW WINDS AHEAD OF SFC-H85
TROUGH HELP TO BRING MUCH WARMER AIR INTO UPR LAKES IN WAKE OF EARLY
WEEK CHILL AND INCREASING MOISTURE AS WELL. JET STREAKS SLIDING
ACROSS THE NORTHERN PLAINS AND OVR ONTARIO SHOULD HELP SYSTEM STAY
FAIRLY ORGANIZED AS IT CROSSES CWA ON WEDNESDAY. MSLP FCSTS DEPICT
THIS AS WELL WITH PRESSURES STEADY OR EVEN SLOWLY FALLING FM TUESDAY
NIGHT INTO WEDNESDAY ACROSS UPPER LAKES. GIVEN OVERALL DRY PATTERN
WE ARE IN CANNOT GET TOO EXCITED ABOUT SIGNIFICANT PRECIPITATION
WITH THE SYSTEM...BUT TOTAL LIQUID COULD CHECK IN AROUND 0.25 INCH
IN SOME AREAS. PTYPE MAY BE ISSUE INITIALLY LATE TUESDAY NIGHT OVER
THE WEST AS SHALLOW COLD AIR HANGS TOUGH IN WAKE OF COLD PUSH EARLY
IN THE WEEK. LATEST MODEL RUNS INDICATE POTENTIAL FOR FROZEN PRECIP
IS NOT AS HIGH AS BEFORE AS SOUTH WINDS ADVECT WELL ABOVE FREEZING
DWPNTS INTO UPR MI BY DAYBREAK WEDNESDAY. OVERALL...MAY BE SOME SNOW
OR PERHAPS FREEZING RAIN...BUT AS IT STANDS NOW IT WOULD BE PRETTY
SHORT LIVED. SOME POTENTIAL SOME SNOW AS SYSTEM EXITS ON WEDNESDAY
NIGHT. 850MB/925MB TEMPS AS LOW AS -10C/-6C WOULD EVEN OPEN DOOR TO
BRIEF LAKE ENHANCED SNOW OVR HIGHER TERRAIN OF WEST GIVEN ENOUGH
MOISTURE REMAINS AS COLDER AIR WORKS INTO UPR LAKES REGION.
IN THE EXTENDED...FRIDAY SYSTEM THAT ECMWF HAS BEEN SHOWING OFF AND
ON THE LAST FEW DAYS WAS OFF ON THE 00Z RUN BUT IS KIND OF BACK ON
AGAIN WITH THE 12Z RUN...THOUGH BULK OF HEAVIER QPF REMAINS SOUTH OF
UPR MI. GFS IS MUCH FARTHER SOUTH. SOUTHERN TRACK DOES MAKE SOME
SENSE AS PRIMARY FRONTAL BOUNDARY IS FCST TO SETTLE INTO THE
NORTHERN PORTIONS OF THE OHIO VALLEY IN WAKE OF THE WEDNESDAY SYSTEM
AND SINCE BETTER CHANCE OF CYCLOGENESIS WOULD BE ALONG THE BETTER
SFC TEMPERATURE GRADIENT. SYSTEM IS STILL NEAR THE ALLUTIANS IN THE
PACIFIC SO THERE LIKELY WILL BE SOME JUMPING AROUND ON THE POSITION
OF THE LOW YET THIS WEEK. FOR NOW THOUGH...POPS WILL STAY ON THE LOW
SIDE FOR THIS SYSTEM WITH THE HIGHER POPS OVER THE SOUTHERN CWA
THURSDAY NIGHT AND FRIDAY. ECMWF IDEA FM 12Z/14 APRIL AND 12Z THIS
MORNING WOULD INDICATE SIGNIFICANT SNOW OVR PORTIONS OF UPR LAKES
INCLUDING UPR MI.
BEYOND FRIDAY APPEARS DRY WEATHER IS IN STORE FOR NEXT WEEKEND. WILL
NOT BE ESPECIALLY WARM THOUGH AS LARGER SCALE TROUGH RESIDES OVR
MUCH OF EASTERN CANADA AND EASTERN CONUS. MODELS SHOW ANOTHER WAVE
DIVING IN FM THE PACIFIC TROUGH BUT WITH EXPECTED AMPLITUDE OF
TROUGH THIS SYSTEM WILL PROBABLY STAY TO THE SOUTH OF UPR LAKES AS
THE LATE WEEK ONE DOES. SFC-H85 RIDGE WILL BE OVERHEAD LEADING TO
LIGHT WINDS/LK BREEZES. BEST CHANCE FOR DAYTIME TEMPS AT LEAST NEAR
NORMAL WILL BE WELL INLAND FM THE LAKES TOWARD WISCONSIN BORDER.
COULD ALSO BE CHILLY NIGHTS AS WELL...WITH TEMPS POSSIBLY IN THE
TEENS AND 20S. RELATIVE HUMIDITIES LIKELY WILL BE ON THE LOW SIDE
FOR THE WEEKEND AS WELL.
APPEARS PATTERN BEGINS TO CHANGE DAYS 8-10 OR STARTING ON 24 APRIL
AS STRONG RIDGE BUILDS FM CNTRL CONUS INTO WESTERN GREAT LAKES.
GIVEN LACK OF RAINFALL THIS MONTH AND SINCE WE ARE STILL NOT
COMPLETELY GREENED UP OVR UPR MI...THE WARMER AND DRY WEATHER WILL
PROBABLY LEAD TO INCREASING FIRE WEATHER ISSUES. PLENTY OF TIME TO
DIAGNOSE THIS THOUGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 143 PM EDT SUN APR 15 2012
COMPLICATED FORECAST OVER THE NEXT 24 HOURS WITH WARM FRONT SOUTH OF
THE AREA TODAY AND THIS EVENING...AND A VERY DYNAMIC SYSTEM SET TO
MOVE DIRECTLY OVER UPPER MI TONIGHT. RAIN AND ISOLATED THUNDER WILL
MOVE INTO UPPER MICHIGAN THIS AFTERNOON INTO TONIGHT. THUNDER WILL
LIKELY BE AWAY FROM THE TERMINALS...THOUGH BEST CHANCE WILL BE AT
SAW. MOST CONCERN RIGHT NOW IS WITH CIGS DROPPING FAST AT ALL SITES.
MOISTURE IS INCREASING AND FLOW HAS BECOME MORE EASTERLY EARLY THIS
AFTERNOON...SO EXPECT CIGS TO FALL QUICKLY AT CMX. CONDITIONS MAY BE
DOWN TO NEAR AIRFIELD LANDING MINIMUMS STARTING LATE THIS AFTERNOON.
FOG ALREADY OVER LAKE MI IS REVEALING PLENTY OF MOISTURE FOR SE
UPSLOPE WINDS AT SAW TO DECREASE CIGS AND VIS LATE THIS AFTERNOON.
LLWS IS POSSIBLE LATE THIS EVENING AT SAW AS LOW-LEVEL WINDS
STRENGTHEN JUST ABOVE A SHALLOW SURFACE COOL LAYER AHEAD OF THE
FRONT. RAIN SHOULD LIGHTEN UP AND VIS/CIGS SHOULD IMPROVE TONIGHT AS
THE WARM FRONT MOVES NORTH OF THE AREA. HEADING INTO MONDAY...WINDS
WILL QUICKLY TURN TO THE NNW AT ALL SITES IN THE MORNING. EXPECT
VERY GUSTY WINDS...LIKELY OVER 30KTS. -RA CHANGING TO -SN WILL ALSO
BE LIKELY DURING THE MORNING AT IWD AND CMX AS COLD AIR FILTERS INTO
THE AREA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 PM EDT SUN APR 15 2012
SFC LOW TRACKING FROM NE NEBRASKA TO UPPER MI/SE LAKE SUPERIOR
TONIGHT/MON MORNING WILL BRING A NE TO N GALE EVENT TO LAKE SUPERIOR
TONIGHT AND MON. GALES HAVE BEEN A LITTLE SLOW TO DEVELOP OVER THE
FAR W THIS AFTN...BUT WINDS SHOULD QUICKLY RAMP UP OVER THE NEXT FEW
HRS AS PRES FALLS INCREASE IN MAGNITUDE TO THE SW OF THE LAKE AHEAD
OF THE APPROACHING SFC LOW. AS THE LOW SHIFTS ACROSS UPPER MI/SE
LAKE SUPERIOR AND THEN E MON...NE WINDS WILL BACK N WITH GALES
QUICKLY EXPANDING E ACROSS THE LAKE. SHARP CAA/STRONG LOW-LEVEL
INSTABILITY WILL SUPPORT FREQUENT HIGH END GALE GUSTS. WINDS WILL
DIMINISH TO UNDER 20KT FROM W TO E MON NIGHT/EARLY TUE AS HIGH PRES
RIDGE BUILDS SE TO THE UPPER LAKES. LIGHTER WINDS WILL PERSIST THRU
TUE AFTN. NEXT LOW PRES SYSTEM MOVING THRU THE UPPER LAKES WED WILL
BRING ANOTHER PERIOD OF 15-25KT WINDS WED/THU...WITH THE STRONGER
WINDS AFFECTING MAINLY THE E HALF OF THE LAKE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 5 PM MONDAY TO 2 AM EDT TUESDAY FOR LSZ251-267.
GALE WARNING FROM 11 AM MONDAY TO 2 AM EDT TUESDAY FOR LSZ266.
GALE WARNING UNTIL 2 PM EDT /1 PM CDT/ MONDAY FOR LSZ162.
GALE WARNING FROM 8 PM THIS EVENING TO 8 PM EDT MONDAY FOR
LSZ242>244-263-264.
GALE WARNING FROM 11 AM TO 8 PM EDT MONDAY FOR LSZ265.
GALE WARNING FROM 2 PM MONDAY TO 2 AM EDT TUESDAY FOR LSZ249-250.
GALE WARNING FROM 2 PM TO 8 PM EDT MONDAY FOR LSZ248.
GALE WARNING FROM 5 AM TO 8 PM EDT MONDAY FOR LSZ245.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ221-248-
250.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...TK
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1256 AM EDT SUN APR 15 2012
.SYNOPSIS...
ISSUED AT 412 PM EDT SAT APR 14 2012
A WARM FRONT WILL BRING A PERIOD OF THUNDERSTORMS WITH LOCALLY
HEAVY RAINFALL LATE TONIGHT INTO MID MORNING SUNDAY. THE COLD
FRONT MONDAY NIGHT WILL BRING AN PERIOD OF THUNDERSTORMS WITH
GUSTY WINDS WITH IT. NO MONDAY IT WILL BECOME VERY WINDY WITH
FALLING TEMPERATURES DURING THE DAY AS WELL AS SCATTERED SHOWERS.
FROST AND FREEZING TEMPERATURES ARE EXPECTED BY TUESDAY MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 412 PM EDT SAT APR 14 2012
LITTLE CHANGE IN THINKING FROM MY LATE MORNING DISCUSSION. A
PERIOD OF THUNDERSTORMS (NOT SEVERE) WITH THE WARM FRONT
TONIGHT...DRY MIDDAY SUNDAY UNTIL MID EVENING...THEN THE FRONTAL
RAIN BAND WITH GUSTY WINDS LATE EVENING SUNDAY INTO THE EARLY
MORNING HOURS OF MONDAY.
TONIGHT THE LOW LEVEL JET BIFURCATES WITH PART OF IT GOING INTO OHIO
AND THE REST OF IT HEADED TOWARD MN/WI. THAT ALSO IS NOT CONDUCIVE
FOR CONVECTION HERE. IT IS NOT UNTIL MID MORNING SUNDAY THE
SOUTHERN BRANCH OF THE BIFURCATED LOW LEVEL JET EVEN SHOWS A SIGN OF
GETTING INTO THE I-94 REGION AND BY THEN IT IS WEAKENING. THE
PRIMARY CORE STAYS OVER WI/MI/IA THROUGH THE DAY AND SLOWLY
DEVELOPS NORTHWARD NOT EASTWARD. SO I EXPECT A BAND OF
THUNDERSTORMS TO HEAD NORTH THROUGH LOWER MICHIGAN MID MORNING BUT
WILL LIKELY NOT BE SEVERE (NOT SURFACE BASED). THE HRRR RUC FROM
THE 16Z MODEL RUN SHOWS THIS NICELY. SO MOST OF THE RAIN FROM THE
WARM FRONTAL RAIN BAND WILL BE BETWEEN MIDNIGHT AND 10 AM MONDAY.
THE MODELS AND SOUNDING SHOW NO SURFACE BASED CAPE AND ONLY 500 TO
1000 J/KG OF MOST UNSTABLE CAPE (FROM 800 MB LAYER). THUS I DO NOT
SEE MUCH OF SEVERE THREAT TONIGHT WITH THESE STORMS. JUST LOCALLY
HEAVY RAINFALL.
ON SUNDAY THE WARM FRONT LIFTS NORTH OF THE CWA AND SO WILL THE
ASSOCIATED CONVECTION. THERE IS SURFACE BASED INSTABILITY SUNDAY BUT
NO FOCUS SO I DO NOT BELIEVE WE WILL BE SEEING MUCH IF ANY
CONVECTION IN THE GRR CWA DURING THE AFTERNOON. IF THE SUN REALLY
CAME OUT TEMPERATURES COULD REACH 80 SOUTH OF INTERSTATE 96.
SUNDAY NIGHT WILL BE OUR CONVECTIVE "SHOW" IF ONE COULD CALL IT
THAT. IT TAKES UNTIL 2 AM FOR THE LOW LEVEL JET CORE TO GET TO
I-31. WHILE FORECAST SHOWS 1500-2000 J/KG OF SURFACE BASED CAPE
OVER WI SUN AFTERNOON BY THE TIME THIS REACHES LOWER MICHIGAN
AFTER MIDNIGHT IT IS LESS THE 500 J/KG. ON THE OTHER HAND WE DO
STILL HAVE SURFACE BASED CAPE SO AND A 60 TO 70 KNOT LOW LEVEL
JET. GIVEN THE LOW CAPE VALUE LARGE HAIL SEEMS OUT OF THE
QUESTION. MOSTLY GUSTY WINDS BUT WITH WEAK CAPE ONE HAS TO EVEN
WONDER ABOUT THAT. SO I AM NOT EXPECTING A MAJOR SEVERE OUTBREAK
IN OUR CWA FROM THIS EVENT. JUST ISOLATED SEVERE STORMS POSSIBLE
AFTER MIDNIGHT. SPC`S OUTLOOK FOR SUNDAY NIGHT INTO MONDAY AGREES
WITH THIS WITH A 15 PCT CHANCE OVER OUR NW CWA.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 412 PM EDT SAT APR 14 2012
TRENDED POPS LOWER FOR MONDAY AND ALSO TRENDED COOLER FOR MONDAY
NIGHT AND TUESDAY NIGHT. MODEL TRENDS ARE MORE PROGRESSIVE WITH
MOVING THE SURFACE LOW OUT OF THE AREA ON MONDAY. THIS SHOULD
RESULT IN QUICKER CLEARING MONDAY NIGHT...AND REMAINING MOSTLY CLEAR
TUESDAY NIGHT WITH HIGH PRESSURE OVER MI. FROST AND FREEZING TEMPS
WILL BE A CONCERN UNDER THIS SCENARIO...ESPECIALLY TUESDAY NIGHT AS
WINDS SHOULD BE LIGHTER.
NEXT CHANCE OF PCPN SHOULD HOLD OFF UNTIL WED AFTERNOON OR EVENING
AS A NORTHERN STREAM WAVE BRINGS A COLD FRONT LATE WED NIGHT OR
EARLY THU. THE FRONT THEN STALLS TO OUR SOUTH WITH OVER-RUNNING
PCPN LINGERING. IT APPEARS THE CWA WILL BE ON THE NORTHERN FRINGE
OF THIS PCPN...SO I HAVE HIGHER POPS IN THE SOUTHERN CWA...AND LOWER
POPS NORTH. THE EURO HOLDS ON TO PCPN RIGHT INTO SAT...BUT THE GFS
GOES DRY. HAVE FAVORED THE DRIER GFS AS THE PATTERN LOOKS MORE
PROGRESSIVE THAN WHAT THE EURO SUGGESTS. TEMPS WILL REMAIN COOL WITH
NE LOW LEVEL FLOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1256 AM EDT SUN APR 15 2012
MAIN CONCERNS WITH THE 06Z TAFS WILL BE CONVECTIVE TRENDS AND
ASSOCIATED CONDITIONS THROUGH THE PERIOD...AND WIND GUST
POTENTIAL.
COMPLEX OF STORMS OVER NRN IL/SRN WI/ERN IA AS OF 05Z IS EXPECTED
TO CONTINUE MOVING E/NE TOWARD THE AREA. EXTRAPOLATION OF THESE
STORMS PUTS THEM INTO THE WRN FOUR TERMINALS AROUND 07Z OR
SO...AND THE KJXN AND KLAN AROUND 08Z OR SO. WE ARE EXPECTING
MAINLY MVFR CONDITIONS WITH SOME TEMPO IFR DUE TO VSBY AND SOME
CIGS. THESE STORMS WILL THEN GRADUALLY LIFT TO THE NORTH AFTER
DAYBREAK AS A WARM FRONT MOVES NORTH. SHOWERS AND STORMS SHOULD
CLEAR THE TERMINALS BY 15Z.
ONCE THE STORMS MOVE NORTH...THE AREA WILL GET INTO THE WARM AIR.
WE WILL SEE SRLY WINDS INCREASE WITH GUSTS 25 TO 30 KNOTS LIKELY.
THESE WINDS WILL CONTINUE ALL DAY AND INTO THE EVENING HOURS AHEAD
OF THE INCOMING FRONT. LOW CLOUDS WILL SCOUR OUT. WE CAN NOT RULE
OUT A POP UP SHOWER OR STORM DURING THE DAY...BUT CHCS ARE TOO LOW
TO INCLUDE IN THE FCST AT THIS TIME. BETTER CHC FOR STORMS WILL
COME IN BEGINNING AROUND RIGHT AROUND THE END OF THIS FCST PERIOD
AROUND 06Z MON.
&&
.MARINE...
ISSUED AT 1023 PM EDT SAT APR 14 2012
WE DECIDED TO BUMP UP THE TIMING ON THE SMALL CRAFT ADVISORY TO
AROUND 06Z TONIGHT. WINDS ALONG THE LAKESHORE AT THE COASTAL SITES
ARE GENERALLY RUNNING 10 TO 15 KNOTS...WITH BIG SABLE POINT COMING
IN AROUND 20 KNOTS ALREADY. LOW LEVEL WINDS WILL BE
INCREASING...HOWEVER STABLE ENVIRONMENT OVER THE LAKE WILL LIMIT
THE WIND SPEED SOME AT THE SFC. WE STILL THINK THAT THERE WILL BE
ENOUGH OF AN INCREASE TO JUSTIFY THE ADVISORY...AND IT VERY WELL
COULD BEGIN BEFORE 12Z SUN.
&&
.HYDROLOGY...
ISSUED AT 412 PM EDT SAT APR 14 2012
LOCALLY HEAVY RAINFALL IS POSSIBLE TONIGHT WITH THE WARM FRONT
PRECIPITATION BAND MOVING NORTHWARD THROUGH SOUTHWEST LOWER
MICHIGAN. AT THIS POINT THROUGH WE DO NOT SEE A LARGE SCALE GENERAL
HEAVY RAINFALL. MOST LOCATIONS TONIGHT SHOULD GET AROUND A HALF
INCH. THE COLD FRONT RAIN BAND SHOULD NOT BE AS HEAVY...GENERALLY
AROUND A QUARTER INCH. THIS SHOULD NOT CAUSE TO MANY PROBLEMS FOR
OUR RIVERS BUT COULD LOCALLY CAUSE ISSUES ON SMALLER STREAMS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT MONDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...JK
AVIATION...NJJ
HYDROLOGY...WDM
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
402 PM CDT SUN APR 15 2012
.DISCUSSION...
MAIN EMPHASIS IS IN THE SHORT TERM WITH A GOOD CHANCE FOR SEVERE
WEATHER THIS AFTERNOON AND EARLY EVENING...RAIN OVERNIGHT...AND A
BRIEF CHANGE OVER TO SNOW MONDAY MORNING BEFORE THE PRECIP MOVES
OUT.
TORNADO WATCH IS IN EFFECT THIS AFTERNOON/EVENING. VISIBLE
SATELLITE CONTINUES TO SHOW GOOD CLEARING AND DESTABILIZATION IN
THE WARM SECTOR WITH GOOD DRYING ALONG WITH 20-40M 500MB HEIGHT
FALLS SHOWING UP IN WESTERN IA. THE WARM FRONT STRETCHES FROM
SOUTHWEST MN UP THROUGH THE NORTHERN TWIN CITIES METRO AND INTO
WEST CENTRAL WI. OBSERVATIONS IN THE NORTH METRO HAVEN`T TURNED
OVER TO SOUTH YET...BUT SHOULD BE CLOSE TO DOING SO.
TORNADOES...HAIL...AND WIND IS POSSIBLE ANYWHERE IN THE WARM
SECTOR AND JUST NORTH OF THE BOUNDARY WHERE LOW LEVEL HELICITY
WILL BE ENHANCED. WE ALREADY HAVE CONVECTIVE INITIATION IN SW MN
AND IA...AND THIS POTENT WAVE WILL HAVE NO TROUBLE DRIVING STORMS
ACROSS THE AREA.
SHEAR IS VERY STRONG PER AREA VWPS AND FORECAST SOUNDINGS. 0-6KM
SHEAR IS MORE THAN SUFFICIENT FOR SUPERCELLS AND 0-1KM SHEAR OF
25-30KTS SUPPORTED BY RUC ANALYSIS AND MPX 18Z SOUNDING. THESE
SOURCES ALSO SUGGEST LITTLE CIN AND AND LOW LCL TO GO ALONG WITH
1000-2000 J/KG OF SURFACE CAPE. THESE ARE STRONG INDICATORS OF
TORNADOGENESIS AND EVEN THE POTENTIAL FOR STRONG TORNADOES GIVEN
THE STRONG SHEAR PROFILE IF SUPERCELLS CAN REMAIN DISCRETE. SUPERCELLS
WILL BE LIKELY WITH TORNADOES POSSIBLE. STORMS THAT FORM AND RIDE
ALONG THE WARM FRONT MAY PRODUCE TORNADOES AND ALSO SWATHS OF
DAMAGING WINDS. TORNADO THREAT DIMINISH GREATER THAN 30KM OR SO
NORTH OF THE WARM FRONT...WHERE STORMS SHOULD BECOME ELEVATED.
THERE WILL STILL BE A HAIL THREAT WITH THE STORMS THAT RIDE NORTH
OF THE WARM FRONT THIS EVENING. AGAIN...TORNADOES ARE POSSIBLE
RIGHT ALONG THE WARM FRONT...INCLUDING THE TWIN CITIES METRO.
LATE TONIGHT...THE COLD FRONT PASSES THROUGH AND 850MB
TEMPERATURES COLLAPSE FROM NORTHWEST TO SOUTHEAST BY MONDAY
MORNING. FORECAST PROFILES AND 1000-850MB LAYER WET BULB ARE COLD
ENOUGH TO SUPPORT SNOW EARLY MONDAY MORNING IN WESTERN AND
PORTIONS OF CENTRAL MN...EVEN INTO NORTHWEST WI. THE QUESTION IS
WHETHER THE THERMAL PROFILE GETS COLD ENOUGH BEFORE THE PRECIP
ENDS. WE THINK IT WILL...BUT ONLY ENOUGH FOR AN INCH OR AT THE
MOST A COUPLE INCHES NEAR AND NORTH OF A LINE FROM ALEXANDRIA TO
LITTLE FALLS TO RICE LAKE WI. A FEW INCHES IS POSSIBLE IN NORTHERN
MN.
IN THE EXTENDED...ZONAL FLOW ACROSS THE LOWER CONUS TRANSITIONS IN
MOST GUIDANCE TO A MORE AMPLIFIED FLOW PATTERN BY NEXT WEEKEND AS
MID-UPPER LEVEL TROUGHING JUST OFF THE WEST COAST DIGS
SOUTHWARD. RIDGING OVER THE WESTERN US AND A DOWNSTREAM TROUGH TO
THE EASTERN US. MODELS AND ENSEMBLES HAVE EMBEDDED IMPULSE
DISAGREEMENT INTO WED/THU...BUT FORECAST SPREAD AND UNCERTAINTY
INCREASE MORE FRI-SUN. WENT HIGHER POPS LATE IN THE FOR THAT NEXT
IMPULSE...WITH THUNDER CHANCES TO GO ALONG WITH THE POPS. RECENT
GFS AND PARALLEL GFS RUNS OFFER MORE AMPLIFIED MID-LATITUDE
FLOW...BUT AS THE ECMWF AND OTHER MODELS OFFER POOR RUN TO RUN
CONTINUITY WITH EMBEDDED SYSTEMS HARD TO ADD TO MUCH CONFIDENCE TO
THE EXTENDED. HPC SOLUTION REFLECTS A BLEND OF GFS/NAEFS/ECMWF
ENSEMBLE MEANS AS WELL.
&&
.AVIATION.../12Z TAF ISSUANCE/
WRFNT CURRENTLY LIES FROM NEAR RWF TO JUST S OF MSP TO S OF EAU AND
SHUD CONTINUE TO MAKE A BIT OF PROGRESS N THIS AFTN...MAINLY E PTN
OF FNT. RADAR IS SHOWING DVLPG SHWRS NEAR THE FNT WITH AIRMASS
QUICKLY BECOMING MORE UNSTABLE S OF FNT. TSTMS COULD DEVELOP VERY
RAPIDLY DURING NEXT HOUR OR SO AFFECTING MAINLY MSP AND EAU.
ELEVATED SHWRS AND TSTMS STRETCH ACRS CENTRAL MN AND WILL CONTINUE
TO AFFECT STC/AXN THRU MUCH OF AFTN. S OF WRMFNT MAINLY AT MSP/EAU
INTO RNH SHUD SEE MVFR TO PRDS OF VFR DRNG AFTN WITH STRATUS
BREAKING UP...HOWEVER IFR CONDS COULD DVLP QUICKLY IN STG TSTMS.
SFC LOW NEAR SUX WILL REACH MSP AREA ARND 00Z AND THEN TRACK INTO NW
WI. STG NLY WINDS ON BACKSIDE OF LOW WILL CREATE WINDS GUSTING 30
TO 35 KTS WITH MVFR/IFR CIGS AND -RA WHICH WILL MIX WITH AND CHG TO
-SN MAINLY AXN/STC AFT 06Z.
KMSP...MAIN CONCERN IS WITH RPDLY DVLPG TSTMS THIS AFTN WITH WRMFNT
VERY NEAR THE ARPT. THESE STORMS COULD QUICLY BECOME SEVERE. WIND
DIRECTION IS PROBLEMATIC WITH SFC BOUNDRY SO CLOSE TO ARPT. TREND
SHUD BE FOR CURRENT ELY WINDS TO BECOME MORE SOUTHERLY NEXT COUPLE
OF HOURS...BUT WILL BE VARIBILITY IN PCPN.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BLUE EARTH-
FARIBAULT-FREEBORN-MARTIN-STEELE-WASECA-WATONWAN.
WIND ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR BLUE EARTH-BROWN-
FARIBAULT-FREEBORN-MARTIN-NICOLLET-STEELE-WASECA-WATONWAN.
WIND ADVISORY FROM 7 PM THIS EVENING TO 7 AM CDT MONDAY FOR
CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-POPE-REDWOOD-
RENVILLE-STEVENS-SWIFT-YELLOW MEDICINE.
WI...NONE.
&&
$$
CLF/BAP
AREA FORECAST DISCUSSION
NWS JACKSON MS
408 PM CDT SUN APR 15 2012
.SHORT TERM...TODAY THROUGH TUESDAY
THE OVERALL SEVERE CONCERN REMAINS MARGINAL LATE TONIGHT THRU MONDAY
MORNING AS THE FRONT STALLS. SOME REDEVELOPMENT OF TSTORMS/SHOWERS
APPEAR POSSIBLE MONDAY AFTN AS FRONT SLOWLY OOZES SOUTH WITH SMALLER
AREA OF ACTIVITY TUESDAY AFTN AS FRONT FINALLY CLEARS THE REGION.
LATEST REGIONAL RADAR DEPICTS A STRUGGLING BROKEN LINE OF SHOWERS AND
A FEW THUNDERSTORMS ACROSS EAST TEXAS. MESO-ANALYSIS CONTINUES TO
SHOW DECENT SB/ML CAPPING ALONG WITH THE 18Z KSHV RAOB IN PRESENCE OF
ELEVATED LFCS AND ~1500 ML CAPE. HI-RES MODEL RUNS AND NUMEROUS
ITERATIONS OF THE HRRR CONTINUE TO SUGGEST A SEMI-ORGANIZED BROKEN
LINE OF THUNDERSTORMS TO APPROACH WRN ZONES BY 10-MIDNIGHT TONIGHT
AND SLOWLY PUSH TOWARDS THE I-55 CORRIDOR BY SUNRISE MONDAY. FAR WRN
AREAS WILL HAVE GREATEST RISK OF STRONG TO PERHAPS A SEVERE STORM AS
DEEP-LYR ASCENT PULLS NORTH. GREATEST RISK OF THESE STORMS WILL BE
STRAIGHT-LINE WINDS OF 40-60 MPH. EXPECT LINE TO WEAKEN AS IT
CONTINUES IT`S SLOW PROGRESSION EWD THROUGH SUNRISE.
THE SYNOPTIC FRONT IS EXPECTED TO STALL ACROSS THE NRN 2/3RDS OF
REGION MONDAY MORNING AS FORCING CONTINUES TO PULL AWAY. AN UNSTABLE
BUT WEAKLY SHEARED AIRMASS WILL REMAIN IN PLACE SOUTH OF THE FRONT
MONDAY. DEPENDING ON HOW THE CONVECTIVE OUTFLOW/COLD POOL MOVES
THROUGH (NMM/ARW SUPPORTED) OR DOES NOT (SEVERAL ITERATION`S OF THE
HRRR) WILL DETERMINE OVERALL COVERAGE OF REDEVELOPMENT OF
SHOWERS/TSTORMS MONDAY AFTN. VIA GLOBAL AND REGIONAL MODELS...ENOUGH
INSTABILITY APPEARS TO BE PRESENT THAT COULD SUPPORT A FEW STRONG
STORMS AS HIGHER PWATS SLOWLY POOL SOUTH OF THE SYNOPTIC FRONT. GIVEN
THE WEAKLY SHEARED...AND SLOW LOW-LVL FLOW SOUTH OF FRONT...SOME
LOCALIZED RAIN AMOUNTS OF SEMI-ORGANIZED PULSE TSTORMS COULD REACH
UPWARDS OF 1-3 INCHES SOUTH OF THE FRONT. OVERALL RAINFALL RATES WILL
DECREASE AS INSTABILITY WANES MON NIGHT/TUE MORNING.
REGION WILL CONTINUE TO LOCATED AHEAD OF DE-AMPLIFYING L/WV TROUGH
THAT WILL PIVOT OVER THE REGION TUESDAY MORNING. THIS FEATURE WILL
PROVIDE IMPETUS TO SLOWLY PUSH THE FRONT FARTHER SOUTH TOWARD THE 84
CORRIDOR BUT ALSO ALLOW FOR SHOWER ACTIVITY TO LINGER OVERNIGHT AND
RE-INVIGORATE AHEAD OF THE FRONT TUESDAY BEFORE IT CLEARS SOUTH OF
THE REGION BY LATE TUESDAY WITH A DRYING TREND EXPECTED WEDNESDAY.
/ALLEN/
.LONG TERM...WEDNESDAY THROUGH NEXT SUNDAY...
THE TROUGH WILL FINALLY PUSH THE FRONT SOUTHEAST AND OUT OF THE
FORECAST AREA TUESDAY NIGHT. QUASI-ZONAL FLOW ALOFT WEDNESDAY INTO
THURSDAY WILL CAUSE CONDITIONS TO WARM HEADING INTO THE END OF THE
WORK WEEK. RAIN CHANCES WILL AGAIN BE ON THE INCREASE FRIDAY INTO
FRIDAY NIGHT AS ANOTHER UPPER TROUGH DIGS SOUTHEAST INTO THE DEEP
SOUTH. THIS WILL FORCE A COLD FRONT THROUGH THE CWA FRIDAY NIGHT INTO
SATURDAY. IF MODELS ARE CORRECT...A RATHER NOTICEABLY COOLER AIRMASS
WILL FILTER INTO THE ARKLAMISS SATURDAY INTO SUNDAY.
AS FAR AS NUMBERS ARE CONCERNED...I STAYED PRETTY CLOSE TO
GUIDANCE. THE ONLY NOTABLE CHANGE WAS TO INCREASE HIGHS A BIT
FOR LOCATIONS EAST OF THE MISSISSIPPI RIVER FRIDAY AFTERNOON. WITH
THE FRONT STILL WEST OF THE RIVER...EVEN WITH CLOUD COVER INCREASING
DURING THE DAY...MUCH OF THE REGION WILL STILL HAVE A GOOD
OPPORTUNITY TO WARM ABOVE THE LOW/MID 70S SUGGESTED BY GUIDANCE. /19/
&&
.AVIATION...MAIN ISSUE TODAY WILL BE WITH STRONG GUSTY
WINDS...ESPECIALLY OVER THE W/NW HALF OF THE AREA. LOOK FOR
SUSTAINED SOUTHERLY WINDS NEAR 25 MPH WITH GUSTS UP TO 40 MPH FOR
WESTERN AND NW AREAS. MOST OF THE CENTRAL AND EASTERN AREAS WILL SEE
BREEZY CONDITIONS WITH SUSTAINED WINDS 15-20 MPH AND GUSTS TO 30
MPH. WINDS WILL DISSIPATE AROUND 00Z. LATER THIS EVE/OVERNIGHT...TIMING
A WEAKENING LINE OF SHRA/TSRA WILL BE THE FOCUS. LOOK FOR MVFR
CEILINGS TO AGAIN DEVELOP AHEAD OF THAT FEATURE. CEILINGS MAY START
LOWERING BY 02-04Z. SOME LOWER RESTRICTIONS WILL BE POSSIBLE WITH AND
JUST BEHIND THE LINE AS PRECIP OCCURS. REDEVELOPMENT OF
SHOWERS/TSTORMS WILL ALSO BE POSSIBLE MON AFTN SOUTH OF THE FRONT
WITH TS BEING TIMED IN AND OUT OF TAFS. /ALLEN/CME/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 65 80 60 76 / 38 69 62 39
MERIDIAN 65 81 61 75 / 6 61 70 59
VICKSBURG 65 81 58 78 / 76 67 48 37
HATTIESBURG 69 85 64 77 / 2 79 70 61
NATCHEZ 65 80 61 76 / 77 71 63 47
GREENVILLE 63 79 57 77 / 99 31 25 12
GREENWOOD 64 80 58 76 / 76 58 36 21
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MSZ018-019-025>027-
034>036-040>042-047.
LA...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LAZ007>009-015-016-
023>026.
AR...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ARZ074-075.
&&
$$
ALLEN/CME/19
AREA FORECAST DISCUSSION
NWS BILLINGS MT
319 PM MDT SUN APR 15 2012
.SHORT TERM...VALID FOR MON AND TUE...
THE 500-HPA FLOW WILL QUICKLY DEAMPLIFY OVER THE UNITED STATES THE
NEXT 24 HOURS...HERALDING A MORE ZONAL FLOW OF PACIFIC ORIGIN THAT
WILL CONTINUE THROUGH THE WEEK. THE 12 UTC MODELS ARE DISPLAYING A
FASTER TREND WITH THE FIRST SHORT WAVE TROUGH IN THAT REGIME WHICH
IS SET TO ARRIVE ON TUE...SO WE FOLLOWED ALONG WITH A FEW FORECAST
ADJUSTMENTS IN THAT DIRECTION TOO. THE GFS MAY BE THE LEAD ON THAT
FASTER SHORT WAVE TIMING...BUT WE NOTE THAT IT IS ON THE AMPLIFIED
SIDE OF THE GUIDANCE SPREAD TOO...SO ITS SOLUTION NEEDS TO BE USED
WITH A BIT OF CAUTION.
TONIGHT...A SHORT WAVE THAT IS A RESIDUAL PART OF THE LARGER-SCALE
TROUGH THAT IMPACTED THE WESTERN HALF OF THE NATION WILL BE MOVING
ACROSS THE AREA. AS OF 21 UTC...PRECIPITATION IS INCREASING ACROSS
SOUTH CENTRAL MT ON THE LEADING EDGE OF QG FORCING WITH THIS WAVE.
SATELLITE AND RADAR IMAGES SHOW A CONVECTIVE NATURE TO MUCH OF THE
MOISTURE...VERIFYING WELL WITH THE LAST FEW HRRR RUNS...WHICH HAVE
SHOWN AN ENHANCED AREA OF CONVECTIVE SHOWERS MOVING SOUTHEAST PAST
BILLINGS AND INTO SHERIDAN BY EARLY EVENING. A MODEST ZONE OF 500-
300 Q-VECTOR CONVERGENCE IS NOTED IN THE 12 UTC GFS AND NAM ACROSS
THOSE SAME AREAS...FURTHER SUPPORTING LIKELY POPS THIS EVENING FOR
THIS REGION. HOWEVER...IF PRECIPITATION REMAINS MORE CONVECTIVE IN
NATURE LIKE IT HAS BECOME EVEN UPSTREAM AT GREAT FALLS...THEN THIS
COULD BE A BIT OVERDONE.
IN THE FOOTHILLS...UPSLOPE FLOW IS EXPECTED TO GENERATE RELATIVELY
GREATER AMOUNTS OF QPF. THE 12 UTC NAM AND GFS BOTH SIMULATE UP TO
A HALF INCH OF LIQUID-EQUIVALENT MOISTURE IN PLACES LIKE RED LODGE
THANKS TO THE UPSLOPE-ASSISTED OMEGA FIELDS. THAT CERTAINLY FAVORS
OUR WINTER WEATHER ADVISORY FOR THOSE AREAS. HAVING SAID THAT...WE
NEED TO NOTE TWO CAVEATS TO THIS SCENARIO...1/ BOTH THE 18 UTC NAM
AND 12 UTC ECMWF HAVE ARRIVED WITH LOWER QPF...AND 2/ SNOW THAT IS
FALLING AT RED LODGE AS OF 21 UTC IS MELTING AS IT FALLS. WE COULD
END UP BEING SOMEWHAT HIGH WITH OUR SNOW FORECAST GIVEN THAT...BUT
THERE IS MORE THAN ENOUGH TO STAY THE COURSE WITH THE ADVISORY FOR
NOW. THE HRRR ALSO SUPPORTS SEVERAL INCHES OF SNOW IN THIS AREA.
MON...WARM AIR ADVECTION AND WESTERLY FLOW WILL BE IN PLACE ACROSS
THE AREA. MIXING TO 700 HPA SHOULD YIELD HIGHS WELL INTO THE 50S F
IN MOST AREAS...WITH SOME 60+ F READINGS POSSIBLE IN SOME LOCALES.
A FEW MODEL SOLUTIONS ATTEMPT TO SIMULATE LIGHT PRECIPITATION WITH
THE WARM AIR ADVECTION REGIME...BUT FORECAST SOUNDINGS SUPPORT DRY
CONDITIONS THANKS TO A DRY BOUNDARY LAYER.
BY TUE...A SHORT WAVE WILL BE MOVING ACROSS THE AREA...BUT GIVEN A
WESTERLY FLOW OF PACIFIC NATURE...WE ARE NOT SURE HOW MANY SHOWERS
WILL OCCUR IN THE LOWER ELEVATIONS. CERTAINLY THIS REGIME DELIVERS
A SOLID FETCH OF FORCING INTO THE WEST-FACING MOUNTAIN SLOPES...SO
WE HAVE GONE WITH LIKELY POPS IN THOSE AREAS. HOWEVER...WE DECIDED
TO MAINTAIN CONTINUITY WITH MAINLY 30 TO 40 PERCENT POPS FOR LOWER
ELEVATIONS AND THE PLAINS...AS FORECAST SOUNDINGS SUPPORT A RATHER
DRY BOUNDARY LAYER. WE ALLOWED CONTINUITY TO RULE HIGH TEMPERATURE
FORECASTS TUE...EVEN THOUGH IT IS SEVERAL F WARMER THAN THE MULTI-
MODEL CONSENSUS IN SOME CASES. THAT IS IN RESPECT TO THE POTENTIAL
FOR ENHANCED MIXING ATTENDANT TO THE WAVE PASSAGE...WHICH SOUNDING
PROFILES DO HINT AT.
ON TUE NIGHT...WE ARE ACTUALLY UNDERCUTTING MOST GUIDANCE SINCE IT
LOOKS LIKE WEAK SURFACE RIDGING WILL MOVE ACROSS THE AREA WITH THE
FASTER WAVE TIMING ON TUE. VERIFICATION FROM SIMILAR EVENTS IN THE
RECENT PAST FAVORED THE BIAS-CORRECTED NAM OR GFS GUIDANCE...WHICH
SUGGESTS LOWS POSSIBLY INTO THE 20S F IN SOME AREAS FOR TUE NIGHT.
OF COURSE...THAT IS PREDICATED ON SOME REDUCTION IN CLOUD COVER...
AND LIGHT WINDS. SCHULTZ
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
A PROGRESSIVE PATTERN STILL EXPECTED TO DOMINATE MUCH OF THE
EXTENDED FORECAST. PREVIOUS MODEL RUNS HAD BEEN DEPICTING
WEDNESDAY AS A DRIER DAY ACROSS THE REGION WITH SOME WEAK RIDGING
BETWEEN TWO SHORTWAVES. HOWEVER...THE LATEST GFS AND ECMWF RUNS
HAVE TRENDED TO A MORE ZONAL FLOW WITH EMBEDDED WEAK VORTICITY
MAXIMA. THIS COMBINED WITH THE MOISTURE EMBEDDED IN THE ZONAL
PACIFIC FLOW...WE EXPECT TO SEE A FEW MORE SHOWERS POSSIBLE ACROSS
THE REGION ON WEDNESDAY. THE BEST CHANCES FOR PRECIP WILL BE IN
THE MOUNTAINS AND IN THE WESTERN PORTION OF THE CWA...WHERE
OROGRAPHIC LIFT WILL BE ENOUGH TO PRODUCE PRECIPITATION...HOWEVER
SOME ISOLATED TO SCATTERED SHOWERS CANNOT BE RULED OUT ACROSS THE
PLAINS. HAVE DECIDED TO INCLUDE WORDING FOR ISOLATED THUNDER IN
THE WEST SINCE FORECAST SOUNDINGS SUGGEST 100 TO 400 J/KG OF MUCAPE
DURING MAX HEATING WEDNESDAY AFTERNOON.
THE MAIN SHORTWAVE APPROACHES THE REGION WEDNESDAY NIGHT INTO
THURSDAY...AND IS PROGGED TO BE A SPLITTING WAVE WITH TWO AREAS OF
MAX QG FORCING. GIVEN THE UNCERTAINTY IN THE EXACT TRACK DETAILS OF
THE SPLITTING WAVE...AND THE CHANCE FOR MORE WIDELY SCATTERED
SHOWERS...HAVE ELECTED TO KEEP BROAD BRUSHED POP CHANCES ACROSS
THE AREA. FORECAST SOUNDINGS AGAIN HINT AT MUCAPE VALUES OF 100 TO
400 J/KG IN THE WESTERN PORTION OF THE CWA THURSDAY AFTERNOON
DURING PEAK HEATING...THUS HAVE ELECTED TO INCLUDE MENTION OF
ISOLATED THUNDER AGAIN.
THE MODELS HAVE FINALLY COME INTO BETTER AGREEMENT ABOUT THE
PATTERN FOR THIS COMING WEEKEND. THE TREND HAS BEEN FOR A MORE
AMPLIFIED RIDGE BUILDING ACROSS THE WESTERN CONUS FRIDAY THROUGH
THE WEEKEND. EXPECT TO SEE A WARMING TREND IN TEMPERATURES AS WE
HEAD INTO THE WEEKEND...WITH DRIER CONDITIONS. HOWEVER...AS THE
RIDGE IS BUILDING IN ON FRIDAY...BOTH THE GFS AND ECMWF HINT AT A
SHORTWAVE TROUGH RIDING OVER THE TOP OF THE RIDGE WHICH COULD
BRING SOME SHOWERS ACROSS THE AREA. THEREFORE...HAVE BUMPED UP THE
POPS FOR FRIDAY TO CLIMATOLOGICAL VALUES. CHURCH
&&
.AVIATION...
UPPER DISTURBANCE DROPPING SOUTHEAST INTO SOUTH CENTRAL MONTANA
AND NORTH CENTRAL WYOMING WILL BRING INCREASING PRECIPITATION
POTENTIAL THROUGH THIS EVENING...MAINLY WEST OF A ROUNDUP TO
BROADUS LINE. MVFR OR LOWER CEILINGS CAN BE EXPECTED IN THIS AREA
THROUGH THE NIGHT...WITH LOCAL IFR CONDITIONS IN PRECIPITATION.
AREAS OF FOG DEVELOPMENT ARE POSSIBLE FROM BILLINGS WEST IN THE
EARLY MORNING HOURS WHICH COULD RESULT IN LOCAL LIFR CONDITIONS.
PRECIPITATION WILL MOVE OUT OF THE AREA BEFORE SUNRISE MONDAY.
SOUTHEAST MONTANA WILL SEE MAINLY VFR CEILINGS WITH LOCAL MVFR
CONDITIONS NEAR ISOLATED SHOWER ACTIVITY. MOUNTAIN OBSCURATION
CONTINUE FOR ALL AREA MOUNTAINS TONIGHT INTO MONDAY MORNING.
CHAMBERS
&&
.PRELIMINARY POINT TEMP/POPS...
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 030/058 039/063 034/062 043/060 036/065 040/066 043/070
61/B 14/W 22/W 33/W 22/W 21/B 11/B
LVM 026/057 036/060 034/058 038/055 032/061 036/063 040/068
71/N 24/W 24/T 43/T 33/W 32/W 21/B
HDN 030/059 036/066 031/064 038/063 036/067 038/069 039/073
51/B 14/W 22/W 33/W 32/W 21/B 11/B
MLS 030/057 037/065 029/063 038/059 038/064 040/070 041/073
31/B 14/W 22/W 34/W 32/W 21/B 11/B
4BQ 026/055 033/065 030/064 037/058 037/064 038/070 038/073
32/W 13/W 22/W 34/W 32/W 21/B 11/B
BHK 027/054 032/063 030/060 037/056 035/060 036/067 036/069
32/W 14/W 22/W 34/W 32/W 21/N 11/B
SHR 028/055 033/063 029/062 037/058 036/064 039/070 040/073
72/W 13/W 22/W 33/W 32/W 21/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MDT MONDAY FOR
ZONES 56-66.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1234 AM CDT SUN APR 15 2012
.AVIATION...06Z KGRI TAF. A LINE OF THUNDERSTORMS ABOUT TO MOVE
INTO THE TAF AREA. AFTER THIS LINE OF STORMS MOVES THRU LOOKS LIKE
THE THUNDERSTORM SHOW IS DONE AT KGRI FOR THE NIGHT. VFR
CONDITIONS EXPECTED THROUGH THE NIGHT...BUT WOULD NOT BE SHOCKED
TO SEE A STRAY SHOWER WITH SOME MVFR CEILINGS PASS THRU
PERIODICALLY THRU THE PERIOD. NO MENTION AT THIS POINT SINCE
CHANCES LOW. BIGGEST CONCERN WILL THE VERY STRONG NORTHWEST WINDS
TODAY. A VERY STRONG PRESSURE GRADIENT WILL PRODUCE GUSTS TO 35KTS
AT TIMES THIS AFTERNOON.
&&
PREV DISCUSSION... /ISSUED 420 PM CDT SAT APR 14 2012/
SHORT TERM...THROUGH SUNDAY AFTERNOON. THE OBVIOUS CONCERN IS THE
EVOLUTION OF SEVERE CONVECTION OVER AT LEAST THE NEXT 6-8 HOURS.
IN SHORT...THE FIRST ROUND OF STRONG-SEVERE CONVECTION IS IN THE
PROCESS OF EXITING FAR EASTERN PORTIONS OF THE CWA...ESSENTIALLY
BRINGING ROUND 1 TO A CLOSE. THESE STORMS RESULTED IN AT LEAST 3
UNCONFIRMED BRIEF TORNADOES NEAR AND SOUTH OF THE STATE
LINE...ALONG WITH SOME LOCALLY HEAVY RAIN IN EXCESS OF 2 INCHES.
THE CONCERN NOW SHIFTS BACK TO THE FAR WESTERN-SOUTHWESTERN
CWA...AS CLEARING SKIES ARE RAPIDLY DESTABILIZING AREAS CLOSER TO
THE SURFACE DRYLINE FROM SOUTHWEST NEB DOWN ACROSS WESTERN KS. AS
A RESULT...WANT TO EMPHASIZE THAT THIS EVENT IS FAR FROM BEING
OVER.
PARAMETERS FOR ADDITIONAL DEVELOPMENT ARE VERY FAVORABLE FOR
HIGH-END SEVERE...AS THE 110+KT UPPER LEVEL JET STREAK CURRENTLY
MAKING ITS WAY INTO FAR WESTERN KS OVERSPREADS THE AREA.
SUPERCELLS ARE LIKELY WITH 0-6KM BULK SHEAR OF AT LEAST 50KT...AND
WITH LOW LEVEL 0-1KM BULK SHEAR OF 30-40 KT. 0-1KM STORM RELATIVE
HELICITY IS QUITE IMPRESSIVE AS WELL...WITH 300-400+ M2/S2 ACROSS
MUCH OF THE CWA...WHICH COULD ONLY INCREASE INTO THE EVENING HOURS
AS THE LOW LEVEL JET STRENGTHENS. FOLLOWING CONVECTIVE REFLECTIVITY
PROGS FROM LATEST HRRR...ALONG WITH 12Z RUNS OF 4KM WRF-NMM...ALONG
WITH LATEST RUC FIELDS...SIGNIFICANT SURFACE-BASED INSTABILITY
WILL CONTINUE SURGING NORTHEAST INTO THE CWA THROUGH THE NEXT
SEVERAL HOURS WITH LOW LEVEL CAPE IN EXCESS OF 2000 J/KG
PERSISTING WELL INTO THE EVENING. HRRR SUGGESTS A COMBINATION OF
DISCRETE SUPERCELLS AND QUASI LINEAR STORM MODES WILL CONTINUE
WELL INTO THE EVENING...WITH SOUTHERN AND WESTERN PORTIONS OF THE
CWA LIKELY MOST UNDER THE GUN. ALTHOUGH HYDRO ISSUES SEEM TO BE
MINIMAL SO FAR...ANOTHER 1-2 INCHES OF RAIN ACROSS ROUGHLY THE
SOUTHEAST 1/3 OF THE CWA ON TOP OF WHAT FELL EARLIER COULD LEAD TO
SOME ISSUES.
SO FAR...WIND ADVISORY IN EFFECT FOR KS ZONES THROUGH 00Z IS NOT
PANNING OUT VERY WELL WITH CONVECTIVE ACTIVITY INTERFERING...AND
ALTHOUGH NEITHER AN IMMEDIATE CANCELLATION OR AN EXTENSION IS NOT
PLANNED AT THIS TIME...WILL PROBABLY SEE STRONGER SOUTHERLY WINDS
ACTUALLY PICK UP OVERNIGHT AS THE SURFACE LOW DEEPENS TO AROUND
987MB IN THE NORTHEAST CO/SOUTHWEST NEB AREA. SPEAKING OF WIND...A
GOOD CHUNK OF THE CWA WILL ALMOST CERTAINLY NEED AN ADVISORY
DURING THE DAY SUNDAY...AS STRONG WINDS INITIALLY ARE FROM THE
SOUTH...BUT THEN FROM THE WEST AND NORTHWEST BEHIND THE COLD
FRONT. INSERTED A STRONG WIND MENTION INTO THE GRIDS AND HAZARDOUS
WEATHER OUTLOOK...BUT WITH EVERYTHING ELSE GOING ON TODAY WILL
DEFER TO MIDNIGHT SHIFT TO PULL THE TRIGGER ON THE NEXT WIND
HEADLINE...WHICH WILL UNDOUBTEDLY BE MORE ROBUST THAN THE CURRENT
ONE.
AS FOR STORM CHANCES LATE TONIGHT...ONLY HAVE 20-30 PERCENT
CHANCES POST-06Z...AND ALTHOUGH THE VAST MAJORITY OF THE CWA
SHOULD BE FREE OF SEVERE WEATHER BY THEN...COULD FORESEE A
MARGINALLY SEVERE STORMS HANGING ON IN NORTHERN ZONES LATE INTO
THE NIGHT. SHOULD BE A LULL IN PRECIPITATION ACROSS MUCH OF THE
CWA LATE TONIGHT INTO SUNDAY MORNING AS THE SYNOPTIC DRY SLOT
SURGES IN...BUT RAIN SHOWERS WILL GRADUALLY SPREAD INTO THE CWA
FROM WEST TO EAST WRAPPING AROUND THE DEPARTING LOW. THE
COMBINATION OF ANY RAIN SHOWERS WITH THE STRONG WINDS WILL MAKE
THE FORECAST HIGHS IN THE MID 50S TO MID 60S FEEL COLDER THAN IT
MAY SOUND.
LONG TERM...SUNDAY EVENING THROUGH NEXT SATURDAY. OVERALL FEW
NOTABLE CHANGES MADE TO PREVIOUS FORECAST...WITH FORECAST BASED ON
A GENERAL BLEND OF THE 12Z ECMWF/GFS.
STARTING OFF RIGHT AWAY SUNDAY EVENING...A WIND ADVISORY MAY
CONTINUE FOR A FEW MORE HOURS ESPECIALLY IN NORTHEAST AREAS...BUT
LIKELY NOT BEYOND 03Z AS THE STRONG SURFACE LOW PULLS GRADUALLY
AWAY ACROSS SOUTHERN MN. LINGERED A SLIGHT CHANCE OF LIGHT SHOWERS
INTO THE EVENING HOURS MAINLY ACROSS THE NORTHEAST...BUT DRY AFTER
MIDNIGHT. HEADING INTO MONDAY...LEFT THE MORNING DRY BUT HAVE
20-30 PERCENT CHANCES FOR SHOWERS IN THE AFTERNOON AS A TRAILING
SHORTWAVE TRACKS OUT OF SOUTHERN SD INTO NORTHERN NEB. NEXT SLIGHT
CHANCE FOR SHOWERS ARRIVES IN NORTHEAST COUNTIES FOR TUESDAY NIGHT
AS THE NEXT QUICK MOVING WAVE PASSES BY IN QUASI-ZONAL FLOW ALOFT.
A FAIRLY ACTIVE UPPER PATTERN CONTINUES INTO THE LATTER PART OF
THE WEEK...AND MAINTAINED 20-30 PERCENT CHANCES FOR SHOWERS/STORMS
FROM THURS INTO THURS NIGHT AS THE NEXT WAVE CROSSES THE REGION.
AT THIS TIME...SEVERE WEATHER THREAT APPEARS LOW. BEYOND THURSDAY
NIGHT...MAINTAINED A DRY FORECAST THROUGH SATURDAY AS THERE ARE
SUGGESTIONS OF AT LEAST WEAK SHORTWAVE RIDGING BUILDING INTO THE
PLAINS.
TEMPERATURE WISE THROUGH THE EXTENDED...HAVE MOST DAYS IN THE
LOW-MID 70S FOR HIGHS...EXCEPT FOR COOLER UPPER 50S-LOW 60S ON
MONDAY. AS FOR OVERNIGHT LOWS...COULD EVENTUALLY NEED TO INSERT
SOME FROST WORDING FOR SUNDAY NIGHT AND/OR MONDAY NIGHT WITH LOWS
IN THE MID-UPPER 30S...ALTHOUGH BREEZES MAY REMAIN JUST STRONG
ENOUGH TO PRECLUDE MUCH DEVELOPMENT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
212 PM EDT SUN APR 15 2012
.SYNOPSIS...
SHOWERS ARE EXPECTED THIS AFTERNOON TO EARLY EVENING AS A WARM
FRONT MOVES THROUGH THE AREA...ESPECIALLY FOR CENTRAL NEW
YORK...AND LIFTING NORTHWARD INTO TONIGHT. WITH THE PASSAGE OF THE
WARM FRONT TONIGHT...HIGHS WILL INTO THE 80S MOST LOCATIONS MONDAY
AFTERNOON. A COLD FRONT WILL BRING A SHOT AT SHOWERS AND
THUNDERSTORMS TOWARD MONDAY EVENING AND INTO THE OVERNIGHT. BEHIND
THE FRONT TEMPERATURES RETURN TO MORE SEASONABLE LEVELS FOR
MIDWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1020 AM UPDATE...RAISED POPS TO LOW CAT FOR THE NRN 1/3 OF THE
FCST AREA AND REMOVED THUNDER THREAT. ACTIVITY WILL BCM MORE
SHOWERY IN NATURE AS IT MOVS INTO CNTRL NY BUT ENUF CVRG TO
WARRANT CAT POPS NRN ZONES. PREV BLO...
855 AM UPDATE...FOR THE MRNG UPDATE WE HAVE OPTED TO RAISE POPS TO
LOW LIKELY ACRS A GOOD PORTION OF CNTRL NY AS THE NXT WAVE APRCHS
LATER THIS MRNG AND AFTN. GIVEN THE CLDS AND XPCTD SHRA WE ALSO
TWEAKED DOWN MAXES BY A FEW DEG. PREV BLO...
4 AM UPDATE...THE FORECAST IS IN VERY GOOD SHAPE AND NOT MUCH TO
CHANGE. AN AREA OF SHOWERS NOW OVER THE EASTERN PART OF THE CWA
WILL EXIT STAGE RIGHT PRIOR TO DAYBREAK WITH MOST OF THIS MORNING
ENDING UP DRY. WE WAIT THE ARRIVAL OF A WARM FRONT NOW OVER THE
OHIO VALLEY LATER TODAY. HI RES MODELS SUCH AS THE
ARW...NMM...NAM12 AND HRRR ARE ALL IN GOOD AGREEMENT WITH SOME
SCT. SHOWERS DEVELOPING OVER THE WESTERN AND CENTRAL PART OF OUR
CWA...MAINLY NORTH OF THE NY/PA LINE...BETWEEN 15Z AND 18Z. AS THE
WARM FRONT LIFTS NORTH...MAIN SHOT AT SHOWERS WILL TRACK NORTHEAST
THROUGH THE MOHAWK VALLEY LATER TODAY. BEST SHOT AT SHOWERS IN
NORTHERN PA LOOKS TO BE BRADFORD OR SUSQUEHANNA COUNTY...WITH
AGAIN HIGHEST POPS OVER NY. LEFT IN A SHOT AT ISOLATED THUNDER
TODAY BUT WITH A CAP EARLY THIS MORNING AND PLENTY OF CLOUDS
AROUND...INSTABILITY LOOKS TO BE LACKING TOO MUCH TO BE A REAL
CONCERN FOR MORE THAN A FEW RUMBLES. TOWARD LATE IN THE
DAY...FOCUS FOR SHOWERS WILL SHIFT NORTH WITH DRIER AIR BUILDING
IN FROM THE SOUTHWEST.
TONIGHT...DRYING TREND WILL CONTINUE AS WE GET INTO THE WARM
SECTOR AND PRONOUNCED DRYING OCCURS FROM NEAR THE SURFACE UP
THROUGH THE ENTIRE COLUMN. IT DOES APPEAR A FEW SHOWERS MAY
LINGER OR HANG UP OVER ONEIDA COUNTY BUT EVEN HERE WE DRY OUT
TOWARD OR SLIGHTLY AFTER MIDNIGHT AT THE LATEST. LIKE THE PREVIOUS
FORECASTER`S IDEA OF WARMER THAN GUIDANCE AND STAYED THE COURSE.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
MONDAY...BREAK OUT THE SHORTS. SEE LITTLE TO CHANGE FROM OUR
FORECAST OF 80-86 ACROSS THE CWA. STILL EXPECTING MOST OF THE DAY
TO BE DRY WITH EXCELLENT AGREEMENT BETWEEN THE MODELS...INCLUDING
THE GFS/NAM/CANADIAN ALONG WITH THE HIGHER RESOLUTION MODELS. AS
A COLD FRONT APPROACHES POPS WILL INCREASE OVER THE WESTERN FINGER
LAKES INTO THE WESTERN MOHAWK VALLEY BETWEEN 21Z AND 0Z. AS FAR AS
SEVERE WEATHER POTENTIAL GOES...THE TIMING OF THE FRONT...IF
TOTALLY CORRECT AS IT STANDS NOW...MAY BE JUST A TAD TOO LATE FOR
PEAK HEATING AND THE BEST INSTABILITY. A GOOD EXAMPLE OF THIS IS
THE NAM BUFKIT SOUNDINGS FOR KSYR/KELM/KITH WHICH SHOW CAPES
AROUND 300 J/KG TOWARD EVENING...COMPARED TO KROC WHICH HAS CAPES
IN THE 700 J/KG RANGE. I LOVE THE DEPICTION FROM SPC WITH SLIGHT
RISK MAINLY ACROSS WNY...AND JUST GETTING INTO THE EXTREME WESTERN
PART OF OUR CWA...WITH SEE TEXT ELSEWHERE. THIS MATCHES UP VERY
WELL WITH THE POP FORECAST OUTLINED ABOVE THROUGH 0Z TUESDAY. WE
WILL HAVE TO WATCH THE TIMING VERY CAREFULLY BECAUSE IF THE FRONT
IS JUST A BIT FASTER...AND WE HAVE MORE INSTABILITY TO WORK
WITH...DAMAGING WINDS ARE A REAL THREAT. 0-6 KM BULK SHEAR VALUES
ON BOTH THE GFS AND NAM ARE 50-55 KTS...AND WE HAVE DRY AIR IN
BOTH THE LOW LEVELS (INVERTED V SOUNDING) AND MID-LEVELS.
MONDAY NIGHT...AS THE FRONT MOVES EAST BEST SHOT AT SOME THUNDER
AND SHOWERS WILL BE THROUGH 03Z...WITH MOISTURE AND INSTABILITY
DIMINISHING QUICKLY AS THE NIGHT WEARS ON. WITH THAT IN MIND
HIGHEST POPS WILL BE ROUGHLY NEAR I-81 AND POINTS WEST...WITH
CHANCES FOR MEASURABLE RAIN DROPPING OFF SHARPLY THE FARTHER
SOUTH AND EAST YOU GO.
TUESDAY...COOLER TEMPS FOR SURE BEHIND THE FRONT...BUT A SLOW
COOLING TREND AT 850 MB SHOULD ALLOW FOR A DECENT TEMP GRADIENT.
850S CLOSER TO +5C WILL ALLOW FOR A RANGE OF NEAR 70 OVER PIKE
COUNTY...TO 50S ACROSS THE NORTH WITH 850S SLIDING TO BELOW ZERO.
A SHORT WAVE WILL PASS TO THE NORTH OF OUR AREA BY AFTERNOON. THIS
SYSTEM WILL BE MOISTURE STARVED BUT THE SOUNDINGS ACROSS NORTHERN
ONEIDA COUNTY SHOW JUST ENOUGH MOISTURE TO WARRANT AN ISOLATED
SHOWER UP HERE FOR THE AFTERNOON HOURS. DRIER WEATHER BUILDS IN
TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
UNCERTAINTY BY THE WEEKEND WITH AMPLIFYING PATTERN...AND LARGE
SPREAD AMONG THE GFS ENSEMBLES. GENERALLY ACCEPTED HPC
GRIDS...EXCEPT DID NOT SWING AS COLD FOR TEMPERATURES INTO
SATURDAY BECAUSE HPC HIGHS WERE AT OR BELOW THE COLDEST OF THE GFS
ENSEMBLE MEMBERS. GFS AMPLIFICATION IN THE 12Z RUN TAKES LONGER TO
SET UP COMPARED TO PRIOR RUNS...THAT IS LATER IN THE
WEEKEND...WHILE THE ECWMF TAKES EVEN LONGER...WHICH ALSO COMPELLED
ME TO PULL BACK FROM DROPPING TOO QUICKLY ON THE TEMPERATURES.
PERIOD BEGINS FAIRLY MILD AHEAD OF COLD FRONT THURSDAY...WITH THAT
FRONT PASSING THROUGH IN THE AFTERNOON OR EVENING /MODELS IN
PRETTY GOOD AGREEMENT THIS EARLY IN THE LONG TERM/. I DID NOT GO
BEYOND CHANCE POPS WITH THIS FEATURE BECAUSE OF SUGGESTION IN BOTH
ECWMF AND GFS THAT THE DEEPER MOISTURE AND UPPER LEVEL WAVE WILL
RUN OUT AHEAD OF THE SURFACE FRONT...GETTING OUT OF PHASE AND THUS
OF QUESTIONABLE ORGANIZATION FOR SHOWERS.
FRONT THEN STALLS OUT A BIT TO OUR SOUTH...WHICH WITH MOIST
SOUTHWEST FLOW ALOFT...SETS UP PROLONGED PERIOD IN MOIST
BAROCLINIC LIFT ZONE LATE FRIDAY THROUGH AT LEAST SATURDAY. POPS
WERE INCREASED TO HIGH CHANCE OR LIKELY SATURDAY/SATURDAY NIGHT.
MODELS THEN DIVERGE GREATLY AS TO WHETHER AN UPPER LOW CUTS OFF
AND PHASES WITH A NEW COASTAL LOW SUNDAY...AS PER 12Z GFS...OR
SIMPLY KICKS THE WAVE THROUGH LEAVING THE AREA DRY LIKE 00Z ECWMF.
TIME OF YEAR SUGGESTS CUT OFF SCENARIO MORE LIKELY...BUT DETAILS
AND PLACEMENT OF HOW THAT OCCURS CAN BE EXPECTED TO FLUCTUATE
GREATLY IN THE MODELS DURING COMING DAYS. DEPENDING ON HOW IT
SHAKES OUT...LOOKS LIKE POTENTIAL FOR RECEIVING THE HIGHEST
PRECIPITATION AMOUNTS OF ANY EVENT OF THE LAST COUPLE
MONTHS...ALBEIT NOT A VERY HIGH HURDLE TO CLEAR.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
WARM FRONT STRETCHES FROM LAKE ERIE...ACROSS THE WESTERN NY/PA
BORDER...THEN CROSSES SLIGHTLY INTO NORTHERN COUNTIES OF PA AS OF
18Z. ALONG AND NORTH OF THIS BOUNDARY...CLOUDS STUCK UNDER SHALLOW
FRONT AND PASSING SHOWERS...WILL CAUSE MVFR CONDITIONS INITIALLY BUT
LIFTING NORTHWARD WITH TIME /SEE TAFS FOR DETAILS/. VFR AREAWIDE
BY EARLY EVENING. WITH SOUTH TO NORTH CLEARING INTO
TONIGHT...SHALLOW YET SHARP INVERSION SETS UP TONIGHT DECOUPLING
THE SURFACE WIND...ABOVE WHICH INCREASING WSW FLOW WILL YIELD LLWS
WITHIN THE LOWEST 2 KFT AGL. ONCE MIXING GETS GOING AFTER DAWN
MONDAY...LOOK FOR INCREASINGLY GUSTY SW WINDS...BUT THUNDER
CHANCES FROM COLD FRONT APPROACHING FROM THE WEST WILL WAIT
UNTIL AFTER 18Z MONDAY.
.OUTLOOK...
MON AFTN/EVNG...BAND SHRA/TSRA ALONG COLD FRONT...MOVING WEST TO
EAST YET WEAKENING WITH TIME...INCLUDING POSSIBLE MVFR AND STRONG GUSTY
WINDS /ESPECIALLY WESTERN TERMINALS/.
MON NGT THRU THU MRNG...MAINLY VFR.
THU AFTN THRU FRI...SCT MVFR IN -SHRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...HEDEN
NEAR TERM...
SHORT TERM...HEDEN
LONG TERM...MDP
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
857 AM EDT SUN APR 15 2012
.SYNOPSIS...SHOWERS AND EVEN THE RUMBLE OF THUNDER ARE POSSIBLE
FROM LATE THIS MORNING INTO THIS AFTERNOON AS A WARM FRONT MOVES
THROUGH THE AREA...WITH THE MOST WIDESPREAD ACTIVITY ACROSS
CENTRAL NEW YORK. WE WILL BE DRY TONIGHT INTO MOST OF MONDAY BUT THE
BIGGER STORY WILL BE THE WARM-UP. WE EXPECT HIGHS TO BE INTO THE
80S MOST LOCATIONS MONDAY AFTERNOON. A COLD FRONT WILL BRING A
SHOT AT SHOWERS AND THUNDERSTORMS TOWARD MONDAY EVENING AND INTO
THE OVERNIGHT. BEHIND THE FRONT TEMPERATURES RETURN TO MORE
SEASONABLE LEVELS FOR MIDWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
855 AM UPDATE...FOR THE MRNG UPDATE WE HAVE OPTED TO RAISE POPS TO
LOW LIKELY ACRS A GOOD PORTION OF CNTRL NY AS THE NXT WAVE APRCHS
LATER THIS MRNG AND AFTN. GIVEN THE CLDS AND XPCTD SHRA WE ALSO
TWEEKED DOWN MAXES BY A FEW DEG. PREV BLO...
4 AM UPDATE...THE FORECAST IS IN VERY GOOD SHAPE AND NOT MUCH TO
CHANGE. AN AREA OF SHOWERS NOW OVER THE EASTERN PART OF THE CWA
WILL EXIT STAGE RIGHT PRIOR TO DAYBREAK WITH MOST OF THIS MORNING
ENDING UP DRY. WE WAIT THE ARRIVAL OF A WARM FRONT NOW OVER THE
OHIO VALLEY LATER TODAY. HI RES MODELS SUCH AS THE
ARW...NMM...NAM12 AND HRRR ARE ALL IN GOOD AGREEMENT WITH SOME
SCT. SHOWERS DEVELOPING OVER THE WESTERN AND CENTRAL PART OF OUR
CWA...MAINLY NORTH OF THE NY/PA LINE...BETWEEN 15Z AND 18Z. AS THE
WARM FRONT LIFTS NORTH...MAIN SHOT AT SHOWERS WILL TRACK NORTHEAST
THROUGH THE MOHAWK VALLEY LATER TODAY. BEST SHOT AT SHOWERS IN
NORTHERN PA LOOKS TO BE BRADFORD OR SUSQUEHANNA COUNTY...WITH
AGAIN HIGHEST POPS OVER NY. LEFT IN A SHOT AT ISOLATED THUNDER
TODAY BUT WITH A CAP EARLY THIS MORNING AND PLENTY OF CLOUDS
AROUND...INSTABILITY LOOKS TO BE LACKING TOO MUCH TO BE A REAL
CONCERN FOR MORE THAN A FEW RUMBLES. TOWARD LATE IN THE
DAY...FOCUS FOR SHOWERS WILL SHIFT NORTH WITH DRIER AIR BUILDING
IN FROM THE SOUTHWEST.
TONIGHT...DRYING TREND WILL CONTINUE AS WE GET INTO THE WARM
SECTOR AND PRONOUNCED DRYING OCCURS FROM NEAR THE SURFACE UP
THROUGH THE ENTIRE COLUMN. IT DOES APPEAR A FEW SHOWERS MAY
LINGER OR HANG UP OVER ONEIDA COUNTY BUT EVEN HERE WE DRY OUT
TOWARD OR SLIGHTLY AFTER MIDNIGHT AT THE LATEST. LIKE THE PREVIOUS
FORECASTER`S IDEA OF WARMER THAN GUIDANCE AND STAYED THE COURSE.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
MONDAY...BREAK OUT THE SHORTS. SEE LITTLE TO CHANGE FROM OUR
FORECAST OF 80-86 ACROSS THE CWA. STILL EXPECTING MOST OF THE DAY
TO BE DRY WITH EXCELLENT AGREEMENT BETWEEN THE MODELS...INCLUDING
THE GFS/NAM/CANADIAN ALONG WITH THE HIGHER RESOLUTION MODELS. AS
A COLD FRONT APPROACHES POPS WILL INCREASE OVER THE WESTERN FINGER
LAKES INTO THE WESTERN MOHAWK VALLEY BETWEEN 21Z AND 0Z. AS FAR AS
SEVERE WEATHER POTENTIAL GOES...THE TIMING OF THE FRONT...IF
TOTALLY CORRECT AS IT STANDS NOW...MAY BE JUST A TAD TOO LATE FOR
PEAK HEATING AND THE BEST INSTABILITY. A GOOD EXAMPLE OF THIS IS
THE NAM BUFKIT SOUNDINGS FOR KSYR/KELM/KITH WHICH SHOW CAPES
AROUND 300 J/KG TOWARD EVENING...COMPARED TO KROC WHICH HAS CAPES
IN THE 700 J/KG RANGE. I LOVE THE DEPICTION FROM SPC WITH SLIGHT
RISK MAINLY ACROSS WNY...AND JUST GETTING INTO THE EXTREME WESTERN
PART OF OUR CWA...WITH SEE TEXT ELSEWHERE. THIS MATCHES UP VERY
WELL WITH THE POP FORECAST OUTLINED ABOVE THROUGH 0Z TUESDAY. WE
WILL HAVE TO WATCH THE TIMING VERY CAREFULLY BECAUSE IF THE FRONT
IS JUST A BIT FASTER...AND WE HAVE MORE INSTABILITY TO WORK
WITH...DAMAGING WINDS ARE A REAL THREAT. 0-6 KM BULK SHEAR VALUES
ON BOTH THE GFS AND NAM ARE 50-55 KTS...AND WE HAVE DRY AIR IN
BOTH THE LOW LEVELS (INVERTED V SOUNDING) AND MID-LEVELS.
MONDAY NIGHT...AS THE FRONT MOVES EAST BEST SHOT AT SOME THUNDER
AND SHOWERS WILL BE THROUGH 03Z...WITH MOISTURE AND INSTABILITY
DIMINISHING QUICKLY AS THE NIGHT WEARS ON. WITH THAT IN MIND
HIGHEST POPS WILL BE ROUGHLY NEAR I-81 AND POINTS WEST...WITH
CHANCES FOR MEASURABLE RAIN DROPPING OFF SHARPLY THE FARTHER
SOUTH AND EAST YOU GO.
TUESDAY...COOLER TEMPS FOR SURE BEHIND THE FRONT...BUT A SLOW
COOLING TREND AT 850 MB SHOULD ALLOW FOR A DECENT TEMP GRADIENT.
850S CLOSER TO +5C WILL ALLOW FOR A RANGE OF NEAR 70 OVER PIKE
COUNTY...TO 50S ACROSS THE NORTH WITH 850S SLIDING TO BELOW ZERO.
A SHORT WAVE WILL PASS TO THE NORTH OF OUR AREA BY AFTERNOON. THIS
SYSTEM WILL BE MOISTURE STARVED BUT THE SOUNDINGS ACROSS NORTHERN
ONEIDA COUNTY SHOW JUST ENOUGH MOISTURE TO WARRANT AN ISOLATED
SHOWER UP HERE FOR THE AFTERNOON HOURS. DRIER WEATHER BUILDS IN
TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
GNRLY ZONAL FLOW IS FCST IN THE MEDIUM RNG. HI PRES IS XPCTD TO BRING
FAIR WEATHER ON WED...WITH ANOTHER FNTL PSSG ON THU. LATE IN THE
PD...DEEPENING TROF MOVG INTO THE OH VLY MAY BRING UNSETTLED WX
FRI INTO SAT. NO SIG CHGS TO HPC GUIDANCE OTHER THAN BEING A BIT
MORE OPTIMISTIC ON CLD CVR TUE NGT INTO WED.
&&
.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
WRM FNT OVER ERN OH AND NRN PA WILL LFT THRU THE REGION TODAY.
BETTER MIXING BHD THE FNT AND WITH HTG WILL RAISE CIGS BACK INTO
THE VFR CAT LTR TODAY...WITH JUST SOME ISLTD SHWRS. TNGT...INCRSD
MOISTURE AND LGT WINDS MAY RESULT IN A RETURN TO SOME MVFR
CIGS...ESP ACROSS NY WHERE THERE/S BETTER LL MOISTURE.
LGT AND VRBL WND THIS MRNG WILL BECOME SLY WITH MIXING LTR THIS
MRNG...AND GO BACK TO LGT MOST STATIONS TNGT AS THE BNDRY LYR
DECPLS.
.OUTLOOK...
MON...VFR...BUT A BAND OF MVFR CIGS/SHRA PSBL WITH FROPA LATE MON
OR MON EVNG.
MON NGT THRU WED NGT...VFR.
THU...SCT MVFR IN -SHRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...HEDEN
LONG TERM...HEDEN
AVIATION...DGM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
650 AM EDT SUN APR 15 2012
.SYNOPSIS...
A FEW SHOWERS AND EVEN THE RUMBLE OF THUNDER ARE POSSIBLE FROM
LATE THIS MORNING INTO THIS AFTERNOON AS A WARM FRONT MOVES
THROUGH THE AREA. WE WILL BE DRY TONIGHT INTO MOST OF MONDAY BUT
THE BIGGER STORY WILL BE THE WARM-UP. WE EXPECT HIGHS TO BE INTO
THE 80S MOST LOCATIONS MONDAY AFTERNOON. A COLD FRONT WILL BRING A
SHOT AT SHOWERS AND THUNDERSTORMS TOWARD MONDAY EVENING AND INTO
THE OVERNIGHT. BEHIND THE FRONT TEMPERATURES RETURN TO MORE
SEASONABLE LEVELS FOR MIDWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
4 AM UPDATE...THE FORECAST IS IN VERY GOOD SHAPE AND NOT MUCH TO
CHANGE. AN AREA OF SHOWERS NOW OVER THE EASTERN PART OF THE CWA
WILL EXIT STAGE RIGHT PRIOR TO DAYBREAK WITH MOST OF THIS MORNING
ENDING UP DRY. WE WAIT THE ARRIVAL OF A WARM FRONT NOW OVER THE
OHIO VALLEY LATER TODAY. HI RES MODELS SUCH AS THE
ARW...NMM...NAM12 AND HRRR ARE ALL IN GOOD AGREEMENT WITH SOME
SCT. SHOWERS DEVELOPING OVER THE WESTERN AND CENTRAL PART OF OUR
CWA...MAINLY NORTH OF THE NY/PA LINE...BETWEEN 15Z AND 18Z. AS THE
WARM FRONT LIFTS NORTH...MAIN SHOT AT SHOWERS WILL TRACK NORTHEAST
THROUGH THE MOHAWK VALLEY LATER TODAY. BEST SHOT AT SHOWERS IN
NORTHERN PA LOOKS TO BE BRADFORD OR SUSQUEHANNA COUNTY...WITH
AGAIN HIGHEST POPS OVER NY. LEFT IN A SHOT AT ISOLATED THUNDER
TODAY BUT WITH A CAP EARLY THIS MORNING AND PLENTY OF CLOUDS
AROUND...INSTABILITY LOOKS TO BE LACKING TOO MUCH TO BE A REAL
CONCERN FOR MORE THAN A FEW RUMBLES. TOWARD LATE IN THE
DAY...FOCUS FOR SHOWERS WILL SHIFT NORTH WITH DRIER AIR BUILDING
IN FROM THE SOUTHWEST.
TONIGHT...DRYING TREND WILL CONTINUE AS WE GET INTO THE WARM
SECTOR AND PRONOUNCED DRYING OCCURS FROM NEAR THE SURFACE UP
THROUGH THE ENTIRE COLUMN. IT DOES APPEAR A FEW SHOWERS MAY
LINGER OR HANG UP OVER ONEIDA COUNTY BUT EVEN HERE WE DRY OUT
TOWARD OR SLIGHTLY AFTER MIDNIGHT AT THE LATEST. LIKE THE PREVIOUS
FORECASTER`S IDEA OF WARMER THAN GUIDANCE AND STAYED THE COURSE.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
MONDAY...BREAK OUT THE SHORTS. SEE LITTLE TO CHANGE FROM OUR
FORECAST OF 80-86 ACROSS THE CWA. STILL EXPECTING MOST OF THE DAY
TO BE DRY WITH EXCELLENT AGREEMENT BETWEEN THE MODELS...INCLUDING
THE GFS/NAM/CANADIAN ALONG WITH THE HIGHER RESOLUTION MODELS. AS
A COLD FRONT APPROACHES POPS WILL INCREASE OVER THE WESTERN FINGER
LAKES INTO THE WESTERN MOHAWK VALLEY BETWEEN 21Z AND 0Z. AS FAR AS
SEVERE WEATHER POTENTIAL GOES...THE TIMING OF THE FRONT...IF
TOTALLY CORRECT AS IT STANDS NOW...MAY BE JUST A TAD TOO LATE FOR
PEAK HEATING AND THE BEST INSTABILITY. A GOOD EXAMPLE OF THIS IS
THE NAM BUFKIT SOUNDINGS FOR KSYR/KELM/KITH WHICH SHOW CAPES
AROUND 300 J/KG TOWARD EVENING...COMPARED TO KROC WHICH HAS CAPES
IN THE 700 J/KG RANGE. I LOVE THE DEPICTION FROM SPC WITH SLIGHT
RISK MAINLY ACROSS WNY...AND JUST GETTING INTO THE EXTREME WESTERN
PART OF OUR CWA...WITH SEE TEXT ELSEWHERE. THIS MATCHES UP VERY
WELL WITH THE POP FORECAST OUTLINED ABOVE THROUGH 0Z TUESDAY. WE
WILL HAVE TO WATCH THE TIMING VERY CAREFULLY BECAUSE IF THE FRONT
IS JUST A BIT FASTER...AND WE HAVE MORE INSTABILITY TO WORK
WITH...DAMAGING WINDS ARE A REAL THREAT. 0-6 KM BULK SHEAR VALUES
ON BOTH THE GFS AND NAM ARE 50-55 KTS...AND WE HAVE DRY AIR IN
BOTH THE LOW LEVELS (INVERTED V SOUNDING) AND MID-LEVELS.
MONDAY NIGHT...AS THE FRONT MOVES EAST BEST SHOT AT SOME THUNDER
AND SHOWERS WILL BE THROUGH 03Z...WITH MOISTURE AND INSTABILITY
DIMINISHING QUICKLY AS THE NIGHT WEARS ON. WITH THAT IN MIND
HIGHEST POPS WILL BE ROUGHLY NEAR I-81 AND POINTS WEST...WITH
CHANCES FOR MEASURABLE RAIN DROPPING OFF SHARPLY THE FARTHER
SOUTH AND EAST YOU GO.
TUESDAY...COOLER TEMPS FOR SURE BEHIND THE FRONT...BUT A SLOW
COOLING TREND AT 850 MB SHOULD ALLOW FOR A DECENT TEMP GRADIENT.
850S CLOSER TO +5C WILL ALLOW FOR A RANGE OF NEAR 70 OVER PIKE
COUNTY...TO 50S ACROSS THE NORTH WITH 850S SLIDING TO BELOW ZERO.
A SHORT WAVE WILL PASS TO THE NORTH OF OUR AREA BY AFTERNOON. THIS
SYSTEM WILL BE MOISTURE STARVED BUT THE SOUNDINGS ACROSS NORTHERN
ONEIDA COUNTY SHOW JUST ENOUGH MOISTURE TO WARRANT AN ISOLATED
SHOWER UP HERE FOR THE AFTERNOON HOURS. DRIER WEATHER BUILDS IN
TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
GNRLY ZONAL FLOW IS FCST IN THE MEDIUM RNG. HI PRES IS XPCTD TO BRING
FAIR WEATHER ON WED...WITH ANOTHER FNTL PSSG ON THU. LATE IN THE
PD...DEEPENING TROF MOVG INTO THE OH VLY MAY BRING UNSETTLED WX
FRI INTO SAT. NO SIG CHGS TO HPC GUIDANCE OTHER THAN BEING A BIT
MORE OPTIMISTIC ON CLD CVR TUE NGT INTO WED.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
WRM FNT OVER ERN OH AND NRN PA WILL LFT THRU THE REGION TODAY.
BETTER MIXING BHD THE FNT AND WITH HTG WILL RAISE CIGS BACK INTO
THE VFR CAT LTR TODAY...WITH JUST SOME ISLTD SHWRS. TNGT...INCRSD
MOISTURE AND LGT WINDS MAY RESULT IN A RETURN TO SOME MVFR
CIGS...ESP ACROSS NY WHERE THERE/S BETTER LL MOISTURE.
LGT AND VRBL WND THIS MRNG WILL BECOME SLY WITH MIXING LTR THIS
MRNG...AND GO BACK TO LGT MOST STATIONS TNGT AS THE BNDRY LYR
DECPLS.
.OUTLOOK...
MON...VFR...BUT A BAND OF MVFR CIGS/SHRA PSBL WITH FROPA LATE MON
OR MON EVNG.
MON NGT THRU WED NGT...VFR.
THU...SCT MVFR IN -SHRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...HEDEN
NEAR TERM...HEDEN
SHORT TERM...HEDEN
LONG TERM...
AVIATION...DGM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
419 AM EDT SUN APR 15 2012
.SYNOPSIS...
A FEW SHOWERS AND EVEN THE RUMBLE OF THUNDER ARE POSSIBLE FROM
LATE THIS MORNING INTO THIS AFTERNOON AS A WARM FRONT MOVES
THROUGH THE AREA. WE WILL BE DRY TONIGHT INTO MOST OF MONDAY BUT
THE BIGGER STORY WILL BE THE WARM-UP. WE EXPECT HIGHS TO BE INTO
THE 80S MOST LOCATIONS MONDAY AFTERNOON. A COLD FRONT WILL BRING A
SHOT AT SHOWERS AND THUNDERSTORMS TOWARD MONDAY EVENING AND INTO
THE OVERNIGHT. BEHIND THE FRONT TEMPERATURES RETURN TO MORE
SEASONABLE LEVELS FOR MIDWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
4 AM UPDATE...THE FORECAST IS IN VERY GOOD SHAPE AND NOT MUCH TO
CHANGE. AN AREA OF SHOWERS NOW OVER THE EASTERN PART OF THE CWA
WILL EXIT STAGE RIGHT PRIOR TO DAYBREAK WITH MOST OF THIS MORNING
ENDING UP DRY. WE WAIT THE ARRIVAL OF A WARM FRONT NOW OVER THE
OHIO VALLEY LATER TODAY. HI RES MODELS SUCH AS THE
ARW...NMM...NAM12 AND HRRR ARE ALL IN GOOD AGREEMENT WITH SOME
SCT. SHOWERS DEVELOPING OVER THE WESTERN AND CENTRAL PART OF OUR
CWA...MAINLY NORTH OF THE NY/PA LINE...BETWEEN 15Z AND 18Z. AS THE
WARM FRONT LIFTS NORTH...MAIN SHOT AT SHOWERS WILL TRACK NORTHEAST
THROUGH THE MOHAWK VALLEY LATER TODAY. BEST SHOT AT SHOWERS IN
NORTHERN PA LOOKS TO BE BRADFORD OR SUSQUEHANNA COUNTY...WITH
AGAIN HIGHEST POPS OVER NY. LEFT IN A SHOT AT ISOLATED THUNDER
TODAY BUT WITH A CAP EARLY THIS MORNING AND PLENTY OF CLOUDS
AROUND...INSTABILITY LOOKS TO BE LACKING TOO MUCH TO BE A REAL
CONCERN FOR MORE THAN A FEW RUMBLES. TOWARD LATE IN THE
DAY...FOCUS FOR SHOWERS WILL SHIFT NORTH WITH DRIER AIR BUILDING
IN FROM THE SOUTHWEST.
TONIGHT...DRYING TREND WILL CONTINUE AS WE GET INTO THE WARM
SECTOR AND PRONOUNCED DRYING OCCURS FROM NEAR THE SURFACE UP
THROUGH THE ENTIRE COLUMN. IT DOES APPEAR A FEW SHOWERS MAY
LINGER OR HANG UP OVER ONEIDA COUNTY BUT EVEN HERE WE DRY OUT
TOWARD OR SLIGHTLY AFTER MIDNIGHT AT THE LATEST. LIKE THE PREVIOUS
FORECASTER`S IDEA OF WARMER THAN GUIDANCE AND STAYED THE COURSE.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
MONDAY...BREAK OUT THE SHORTS. SEE LITTLE TO CHANGE FROM OUR
FORECAST OF 80-86 ACROSS THE CWA. STILL EXPECTING MOST OF THE DAY
TO BE DRY WITH EXCELLENT AGREEMENT BETWEEN THE MODELS...INCLUDING
THE GFS/NAM/CANADIAN ALONG WITH THE HIGHER RESOLUTION MODELS. AS
A COLD FRONT APPROACHES POPS WILL INCREASE OVER THE WESTERN FINGER
LAKES INTO THE WESTERN MOHAWK VALLEY BETWEEN 21Z AND 0Z. AS FAR AS
SEVERE WEATHER POTENTIAL GOES...THE TIMING OF THE FRONT...IF
TOTALLY CORRECT AS IT STANDS NOW...MAY BE JUST A TAD TOO LATE FOR
PEAK HEATING AND THE BEST INSTABILITY. A GOOD EXAMPLE OF THIS IS
THE NAM BUFKIT SOUNDINGS FOR KSYR/KELM/KITH WHICH SHOW CAPES
AROUND 300 J/KG TOWARD EVENING...COMPARED TO KROC WHICH HAS CAPES
IN THE 700 J/KG RANGE. I LOVE THE DEPICTION FROM SPC WITH SLIGHT
RISK MAINLY ACROSS WNY...AND JUST GETTING INTO THE EXTREME WESTERN
PART OF OUR CWA...WITH SEE TEXT ELSEWHERE. THIS MATCHES UP VERY
WELL WITH THE POP FORECAST OUTLINED ABOVE THROUGH 0Z TUESDAY. WE
WILL HAVE TO WATCH THE TIMING VERY CAREFULLY BECAUSE IF THE FRONT
IS JUST A BIT FASTER...AND WE HAVE MORE INSTABILITY TO WORK
WITH...DAMAGING WINDS ARE A REAL THREAT. 0-6 KM BULK SHEAR VALUES
ON BOTH THE GFS AND NAM ARE 50-55 KTS...AND WE HAVE DRY AIR IN
BOTH THE LOW LEVELS (INVERTED V SOUNDING) AND MID-LEVELS.
MONDAY NIGHT...AS THE FRONT MOVES EAST BEST SHOT AT SOME THUNDER
AND SHOWERS WILL BE THROUGH 03Z...WITH MOISTURE AND INSTABILITY
DIMINISHING QUICKLY AS THE NIGHT WEARS ON. WITH THAT IN MIND
HIGHEST POPS WILL BE ROUGHLY NEAR I-81 AND POINTS WEST...WITH
CHANCES FOR MEASURABLE RAIN DROPPING OFF SHARPLY THE FARTHER
SOUTH AND EAST YOU GO.
TUESDAY...COOLER TEMPS FOR SURE BEHIND THE FRONT...BUT A SLOW
COOLING TREND AT 850 MB SHOULD ALLOW FOR A DECENT TEMP GRADIENT.
850S CLOSER TO +5C WILL ALLOW FOR A RANGE OF NEAR 70 OVER PIKE
COUNTY...TO 50S ACROSS THE NORTH WITH 850S SLIDING TO BELOW ZERO.
A SHORT WAVE WILL PASS TO THE NORTH OF OUR AREA BY AFTERNOON. THIS
SYSTEM WILL BE MOISTURE STARVED BUT THE SOUNDINGS ACROSS NORTHERN
ONEIDA COUNTY SHOW JUST ENOUGH MOISTURE TO WARRANT AN ISOLATED
SHOWER UP HERE FOR THE AFTERNOON HOURS. DRIER WEATHER BUILDS IN
TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
GNRLY ZONAL FLOW IS FCST IN THE MEDIUM RNG. HI PRES IS XPCTD TO BRING
FAIR WEATHER ON WED...WITH ANOTHER FNTL PSSG ON THU. LATE IN THE
PD...DEEPENING TROF MOVG INTO THE OH VLY MAY BRING UNSETTLED WX
FRI INTO SAT. NO SIG CHGS TO HPC GUIDANCE OTHER THAN BEING A BIT
MORE OPTIMISTIC ON CLD CVR TUE NGT INTO WED.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
WRM FNT OVER ERN OH AND NRN PA WILL LFT THRU THE REGION TODAY
BRINGING SCT SHWRS AND BRIEFLY LWRD CIGS. AIR BLO LIFT NEAR THE
SFC IS STILL FAIRLY DRY SO IFR CIGS AND VSBY ARE NOT LIKELY BEFORE
SUNRISE...BUT OCNL MVFR CIGS SEEM LIKELY...ESP OVER THE HILLTOPS
TERMINALS. LIGT WINDS THIS MRNG WILL BECOME SLY ON SUN BHD THE FNT
WITH INCRSD MIXING. ALSO...MIXING WILL HELP RAISE CIGS AND THEY
SHD REMAIN VFR THRU THE END OF THE TAF PD. ANY SHWRS WILL BE LGT
THIS MRNG.
.OUTLOOK...
SUN NGT...VFR.
MON...VFR...BUT A BAND OF MVFR CIGS/SHRA PSBL WITH FROPA LATE MON OR
MON EVNG.
MON NGT THRU WED NGT...VFR.
THU...SCT MVFR IN -SHRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...HEDEN
NEAR TERM...HEDEN
SHORT TERM...HEDEN
LONG TERM...
AVIATION...DGM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
227 AM EDT SUN APR 15 2012
.SYNOPSIS...
A WARM FRONT WILL PASS THROUGH THE REGION TONIGHT INTO
SUNDAY...ACCOMPANIED BY A CHANCE OF SHOWERS AND PERHAPS
THUNDER...WHICH WILL SHIFT NORTHWARD WITH TIME. TEMPERATURES
WILL CONTINUE TO SURGE WARMER SUNDAY AND ESPECIALLY MONDAY...TO
THE TUNE OF 25 DEGREES OR SO ABOVE NORMAL. A COLD FRONT WILL PASS
MONDAY AFTERNOON INTO EVENING...WITH SHOWERS AND A CHANCE OF
THUNDER. TEMPERATURES RETURN TO MORE SEASONABLE LEVELS FOR
MIDWEEK.
&&
.NEAR TERM /THROUGH TODAY/...
1245 AM UPDATE...MINOR UPDATE. INITIALLY DESPITE DECENT RADAR
RETURNS IN SOUTHERN AND CENTRAL NY...WE WERE NOT GETTING PRECIP AT
THE GROUND DUE TO VERY DRY BOUNDARY LAYER CONDITIONS. WITH A FEW
OBS NOW REPORTING VERY LIGHT RAIN...ADDED ISOLATED SHOWERS TO
THESE AREAS OVERNIGHT. THE PREVIOUS AFD IS BELOW...
1010 PM UPDATE... AS DISCUSSED IN THE PREVIOUS
UPDATE...SHOWERS EXITING THE OHIO VLY CONTINUE TO MOVE ACROSS
ACROSS SOUTHWESTERN PA THIS EVENING. CONSIDERING THAT THE LOW-
LEVEL JET IS EXPECTED TO VEER TOWARDS A WESTERLY DIRECTION
OVERNIGHT...CURRENT THINKING IS THAT MUCH OF THE FORECAST AREA
WILL NOT BE IMPACTED BY THIS FEATURE. AS A RESULT...HAVE TRIMMED
POPS EVEN FURTHER WITH THE LATEST UPDATE. CLOSER TO HOME...LATEST
RADAR TRENDS STILL SHOWING ISOLATED LIGHT SHOWER ACTIVITY MOVING
THROUGH THE TWIN TIERS AND NORTHEAST PA...HOWEVER WITH DEWPOINT
DEPRESSIONS STILL REMAINING ANYWHERE BETWEEN 10-20
DEGREES...EXPECT NOTHING MORE THAN A SPRINKLE OR LGT SHOWER AT
BEST. IN GENERAL...HAVE MAINTAINED SLGT CHC TO CHC MENTION FROM
THE TWIN TIERS SOUTH. ASIDE FROM MINOR TEMP/DEWPOINT
ADJUSTMENTS...NO OTHER CHANGES NEEDED AT THIS TIME.
750 PM UPDATE...AS STATED IN THE PREVIOUS NEAR TERM
DISCUSSION...CURRENT ACTIVITY MOVING OVER THE FORECAST AREA IS
HAVING LITTLE IMPACT AS DEWPOINT DEPRESSIONS REMAIN ANYWHERE
BETWEEN 20-25 DEGREES EARLY THIS EVENING. AS THIS INITIAL SHIELD
EXITS STAGE RIGHT...ATTENTION WILL THEN SHIFT TO NEXT AREA OF
PRECIP NOW ENTERING WESTERN PA FROM THE OHIO VLY. QUICK LOOK AT
REGIONAL RADAR MOSAIC SHOWS THIS ACTIVITY MOVING EAST THIS EVENING
IN A DUE EASTERLY MOTION...SUGGESTING MUCH OF THIS ACTIVITY WILL
REMAIN SOUTH OF THE NY/PA STATE LINE..AND POSSIBLY EVEN THE ENTIRE
CWA. LATEST HRRR HIGH RES SIMULATED REFLECTIVITY ALONG WITH THE
LATEST RUC QPF FCST SUPPORT THIS LINE OF THINKING AS THE LOW-LEVEL
JET VEERS AND BECOMES NEARLY WESTERLY OVERNIGHT. BASED ON
THIS...FEEL LITTLE IF ANY PRECIP WILL OCCUR FROM THE FINGER LAKES
NORTH...AND WE HAVE TRIMMED POPS ACROSS THESE AREAS ACCORDINGLY.
WE MAY HAVE TO CONTINUE TO TRIMMING POPS FROM NORTH TO SOUTH WITH
THE NEXT UPDATE BASED ON CURRENT TRAJECTORIES BUT WILL CONTINUE TO
MONITOR TRENDS BEFORE MAKING ANY WHOLESALE CHANGES. ASIDE FROM
THAT...JUST SOME MINOR COSMETIC CHANGES TO TEMPS AND DEWPOINTS.
415 PM UPDATE...DESPITE BUSY LOOKING RADAR WITH INCOMING
SHOWERS...VERY DRY LOW LEVELS ARE MAKING THE TOP DOWN MOISTENING
PROCESS GRADUAL...WITH DEW POINT DEPRESSIONS OF ROUGHLY 30 DEGREES
WEST TO ALMOST 40 DEGREES EAST. ONLY EXPECTING SPRINKLES TO
ENCROACH LATE AFTERNOON TO EARLY EVENING...BEFORE 850MB JET CAN
BRING IN ENOUGH MOISTURE FOR MORE SIGNIFICANT RAIN CHANCES. LATEST
MODEL RUNS ARE AGREEING THAT AN EMBEDDED NORTHERN STREAM SHORTWAVE
WILL DROP WNW TO ENE THROUGH THE AREA 01Z-04Z. MODELS DISAGREE
DETAILS OF SHOWER ACTIVITY...BUT CONSENSUS HAS DEFINITELY SHIFTED
TOWARDS FAVORING SOUTHWESTERN ZONES...BECAUSE OF POSITIONING OF
WARM FRONT...AND EFFECT OF DRY AIR FARTHER NORTH AND EAST.
REGARDLESS...WAVE HEADS OUT SHORTLY AFTER MIDNIGHT FOR A RELATIVE
LULL IN ACTIVITY DURING THE PREDAWN HOURS. POPS HAVE BEEN ADJUSTED
ACCORDINGLY. ALSO...WITH AMOUNT OF CLOUD COVER AND GOOD MIXING...I
WENT WELL ABOVE MAV GUIDANCE AND SLIGHTLY ABOVE MET GUIDANCE FOR
LOW TEMPERATURES.
SUNDAY IS NOT LOOKING VERY FAVORABLE FOR CONVECTION...COMPARED TO
EARLIER MODEL RUNS. SHALLOW WARM FRONT...WITH SURGING HEIGHTS
ALOFT YET DELAYED RESPONSE NEAR THE SURFACE...WILL ALLOW FOR AN
INHIBITIVE CAP TO DEVELOP ABOVE LOWERING CLOUD COVER LATE TONIGHT
INTO SUNDAY MORNING. CLOUD COVER WILL LIMIT AMOUNT OF WARMING IN
THE MORNING. BY THE TIME SURFACE FRONT RETREATS NORTHWARD SUNDAY
AFTERNOON AND LOW CLOUDS START MIXING OUR...CAP WILL BE IN PLACE.
THE OLD ADAGE...NEVER TRUST A WARM FRONT...APPLIES HERE THOUGH. SO I
STILL BRING AN AXIS OF CHANCE POPS NORTHWARD WITH THE WARM FRONT
DURING THE DAY SUNDAY...ERADICATING FROM THE SOUTH DURING THE
AFTERNOON. BECAUSE OF SHALLOW WARM FRONT/CLOUD COVER...I LOWERED
TEMPERATURES SOMEWHAT FOR SUNDAY...THOUGH IT WILL STILL TURN OUT
AT LEAST A FEW TO SEVERAL DEGREES WARMER THAN TODAY /SATURDAY/.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
415 PM UPDATE...DRYING OUT WITH STRONG CAP AMIDST IMPRESSIVE WARM
SECTOR SUNDAY NIGHT. I AGAIN WENT ABOVE GUIDANCE FOR LOWS MONDAY
MORNING...WHICH WILL FEEL EERILY SUMMER-LIKE AT DAWN. THE WARM HEAD
START...850MB TEMPERATURES 2 TO 3 STANDARD DEVIATIONS ABOVE
NORMAL...AND WITH SUNSHINE FOR AT LEAST A MAJORITY OF THE
DAY...WILL YIELD HIGHS ROUGHLY 25 OR SO DEGREES ABOVE NORMAL. THIS
WILL BE WITHIN A FEW TO SEVERAL DEGREES OF RECORD DAILY
HIGHS...THOUGH ACTUALLY BREAKING THE RECORDS IS CURRENTLY NOT
FORECAST /YET/.
MODELS HAVE COME INTO GOOD AGREEMENT ON TIMING OF INCOMING FRONT
MID TO LATE AFTERNOON IN THE WESTERN CWA MONDAY...SLOWING DOWN
WHILE BECOMING MORE FLOW-PARALLEL INTO MONDAY EVENING AS IT EDGES
EASTWARD. STRONG CAP EARLY IN DAY...ERODES TO POINT OF BREAKING AS
FRONT MOVES IN. AT FIRST GLANCE...FRONT APPEARS TO TAKE ANAFRONT
NATURE...AND ACTUALLY EVENTUALLY DOES. HOWEVER...DURING THE DAY
MONDAY...CLOSER INSPECTION REVEALS THAT MOISTURE IS POOLED
IMMEDIATELY ALONG FRONT RATHER THAN BEHIND...AND THERE IS ENOUGH
INSTABILITY AND SHEAR FOR THUNDERSTORMS WHICH COULD BE GUSTY /AT
LEAST IN THE WESTERN HALF OF THE AREA/. THIS WILL BEAR WATCHING IN
COMING MODEL RUNS. FOR NOW...SPC TALKS ABOUT OUR SITUATION WITHIN
THE TEXT OF THE DAY 3 OUTLOOK...BUT NOT ENOUGH CONFIDENCE TO
INCLUDE WITHIN SLIGHT RISK FOR SEVERE. I AGREE THAT UNTIL THERE IS
HIGHER CONFIDENCE IN THE INSTABILITY/CAPE EXISTING ALONG THE
FRONT...TOO EARLY TO MENTION SEVERE POTENTIAL WITHIN THE HAZARDOUS
WEATHER OUTLOOK.
DRAMATIC TEMPERATURE FALL INBOUND FOR TUESDAY BEHIND THE
FRONT...YET ONLY BACK TO NEAR SEASONAL VALUES. COLUMN APPEARS TOO
DRY IN THE MODELS TO SUPPORT MENTIONABLE POPS...SO I TOOK WHAT
LITTLE WE HAD IN THE FORECAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
GNRLY ZONAL FLOW IS FCST IN THE MEDIUM RNG. HI PRES IS XPCTD TO BRING
FAIR WEATHER ON WED...WITH ANOTHER FNTL PSSG ON THU. LATE IN THE
PD...DEEPENING TROF MOVG INTO THE OH VLY MAY BRING UNSETTLED WX
FRI INTO SAT. NO SIG CHGS TO HPC GUIDANCE OTHER THAN BEING A BIT
MORE OPTIMISTIC ON CLD CVR TUE NGT INTO WED.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
WRM FNT OVER ERN OH AND NRN PA WILL LFT THRU THE REGION TODAY
BRINGING SCT SHWRS AND BRIEFLY LWRD CIGS. AIR BLO LIFT NEAR THE
SFC IS STILL FAIRLY DRY SO IFR CIGS AND VSBY ARE NOT LIKELY BEFORE
SUNRISE...BUT OCNL MVFR CIGS SEEM LIKELY...ESP OVER THE HILLTOPS
TERMINALS. LIGT WINDS THIS MRNG WILL BECOME SLY ON SUN BHD THE FNT
WITH INCRSD MIXING. ALSO...MIXING WILL HELP RAISE CIGS AND THEY
SHD REMAIN VFR THRU THE END OF THE TAF PD. ANY SHWRS WILL BE LGT
THIS MRNG.
.OUTLOOK...
SUN NGT...VFR.
MON...VFR...BUT A BAND OF MVFR CIGS/SHRA PSBL WITH FROPA LATE MON OR
MON EVNG.
MON NGT THRU WED NGT...VFR.
THU...SCT MVFR IN -SHRA.
&&
.FIRE WEATHER...
FIRE SENSITIVE CONDITIONS AGAIN THIS AFTERNOON...WITH AREA WIDE
RELATIVE HUMIDITY WELL BELOW 30 PERCENT FOR MOST OF THE AREA...AND
GUSTS NEAR 20 MPH IN THE POCONOS. FINE FUELS CONTINUE TO REMAIN
VERY DRY RUNNING BETWEEN 5 AND 8 PERCENT. HOWEVER...FIRE THREAT
IS NOW BEING MITIGATED BY THICKENING HIGH CLOUDS THE REMAINDER OF
THE AFTERNOON...WHICH WILL LIMIT MIXING DOWN OF WINDS. WITH GUSTS
NOT EXPECTED TO CONSISTENTLY REACH CRITERIA LEVELS...NO RED FLAG
NEEDED.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...CMG/HEDEN/MDP
SHORT TERM...MDP
LONG TERM...
AVIATION...DGM
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1242 AM EDT SUN APR 15 2012
.SYNOPSIS...
A WARM FRONT WILL PASS THROUGH THE REGION TONIGHT INTO
SUNDAY...ACCOMPANIED BY A CHANCE OF SHOWERS AND PERHAPS
THUNDER...WHICH WILL SHIFT NORTHWARD WITH TIME. TEMPERATURES
WILL CONTINUE TO SURGE WARMER SUNDAY AND ESPECIALLY MONDAY...TO
THE TUNE OF 25 DEGREES OR SO ABOVE NORMAL. A COLD FRONT WILL PASS
MONDAY AFTERNOON INTO EVENING...WITH SHOWERS AND A CHANCE OF
THUNDER. TEMPERATURES RETURN TO MORE SEASONABLE LEVELS FOR
MIDWEEK.
&&
.NEAR TERM /THROUGH TODAY/...
1245 AM UPDATE...MINOR UPDATE. INITIALLY DESPITE DECENT RADAR
RETURNS IN SOUTHERN AND CENTRAL NY...WE WERE NOT GETTING PRECIP AT
THE GROUND DUE TO VERY DRY BOUNDARY LAYER CONDITIONS. WITH A FEW
OBS NOW REPORTING VERY LIGHT RAIN...ADDED ISOLATED SHOWERS TO
THESE AREAS OVERNIGHT. THE PREVIOUS AFD IS BELOW...
1010 PM UPDATE... AS DISCUSSED IN THE PREVIOUS
UPDATE...SHOWERS EXITING THE OHIO VLY CONTINUE TO MOVE ACROSS
ACROSS SOUTHWESTERN PA THIS EVENING. CONSIDERING THAT THE LOW-
LEVEL JET IS EXPECTED TO VEER TOWARDS A WESTERLY DIRECTION
OVERNIGHT...CURRENT THINKING IS THAT MUCH OF THE FORECAST AREA
WILL NOT BE IMPACTED BY THIS FEATURE. AS A RESULT...HAVE TRIMMED
POPS EVEN FURTHER WITH THE LATEST UPDATE. CLOSER TO HOME...LATEST
RADAR TRENDS STILL SHOWING ISOLATED LIGHT SHOWER ACTIVITY MOVING
THROUGH THE TWIN TIERS AND NORTHEAST PA...HOWEVER WITH DEWPOINT
DEPRESSIONS STILL REMAINING ANYWHERE BETWEEN 10-20
DEGREES...EXPECT NOTHING MORE THAN A SPRINKLE OR LGT SHOWER AT
BEST. IN GENERAL...HAVE MAINTAINED SLGT CHC TO CHC MENTION FROM
THE TWIN TIERS SOUTH. ASIDE FROM MINOR TEMP/DEWPOINT
ADJUSTMENTS...NO OTHER CHANGES NEEDED AT THIS TIME.
750 PM UPDATE...AS STATED IN THE PREVIOUS NEAR TERM
DISCUSSION...CURRENT ACTIVITY MOVING OVER THE FORECAST AREA IS
HAVING LITTLE IMPACT AS DEWPOINT DEPRESSIONS REMAIN ANYWHERE
BETWEEN 20-25 DEGREES EARLY THIS EVENING. AS THIS INITIAL SHIELD
EXITS STAGE RIGHT...ATTENTION WILL THEN SHIFT TO NEXT AREA OF
PRECIP NOW ENTERING WESTERN PA FROM THE OHIO VLY. QUICK LOOK AT
REGIONAL RADAR MOSAIC SHOWS THIS ACTIVITY MOVING EAST THIS EVENING
IN A DUE EASTERLY MOTION...SUGGESTING MUCH OF THIS ACTIVITY WILL
REMAIN SOUTH OF THE NY/PA STATE LINE..AND POSSIBLY EVEN THE ENTIRE
CWA. LATEST HRRR HIGH RES SIMULATED REFLECTIVITY ALONG WITH THE
LATEST RUC QPF FCST SUPPORT THIS LINE OF THINKING AS THE LOW-LEVEL
JET VEERS AND BECOMES NEARLY WESTERLY OVERNIGHT. BASED ON
THIS...FEEL LITTLE IF ANY PRECIP WILL OCCUR FROM THE FINGER LAKES
NORTH...AND WE HAVE TRIMMED POPS ACROSS THESE AREAS ACCORDINGLY.
WE MAY HAVE TO CONTINUE TO TRIMMING POPS FROM NORTH TO SOUTH WITH
THE NEXT UPDATE BASED ON CURRENT TRAJECTORIES BUT WILL CONTINUE TO
MONITOR TRENDS BEFORE MAKING ANY WHOLESALE CHANGES. ASIDE FROM
THAT...JUST SOME MINOR COSMETIC CHANGES TO TEMPS AND DEWPOINTS.
415 PM UPDATE...DESPITE BUSY LOOKING RADAR WITH INCOMING
SHOWERS...VERY DRY LOW LEVELS ARE MAKING THE TOP DOWN MOISTENING
PROCESS GRADUAL...WITH DEW POINT DEPRESSIONS OF ROUGHLY 30 DEGREES
WEST TO ALMOST 40 DEGREES EAST. ONLY EXPECTING SPRINKLES TO
ENCROACH LATE AFTERNOON TO EARLY EVENING...BEFORE 850MB JET CAN
BRING IN ENOUGH MOISTURE FOR MORE SIGNIFICANT RAIN CHANCES. LATEST
MODEL RUNS ARE AGREEING THAT AN EMBEDDED NORTHERN STREAM SHORTWAVE
WILL DROP WNW TO ENE THROUGH THE AREA 01Z-04Z. MODELS DISAGREE
DETAILS OF SHOWER ACTIVITY...BUT CONSENSUS HAS DEFINITELY SHIFTED
TOWARDS FAVORING SOUTHWESTERN ZONES...BECAUSE OF POSITIONING OF
WARM FRONT...AND EFFECT OF DRY AIR FARTHER NORTH AND EAST.
REGARDLESS...WAVE HEADS OUT SHORTLY AFTER MIDNIGHT FOR A RELATIVE
LULL IN ACTIVITY DURING THE PREDAWN HOURS. POPS HAVE BEEN ADJUSTED
ACCORDINGLY. ALSO...WITH AMOUNT OF CLOUD COVER AND GOOD MIXING...I
WENT WELL ABOVE MAV GUIDANCE AND SLIGHTLY ABOVE MET GUIDANCE FOR
LOW TEMPERATURES.
SUNDAY IS NOT LOOKING VERY FAVORABLE FOR CONVECTION...COMPARED TO
EARLIER MODEL RUNS. SHALLOW WARM FRONT...WITH SURGING HEIGHTS
ALOFT YET DELAYED RESPONSE NEAR THE SURFACE...WILL ALLOW FOR AN
INHIBITIVE CAP TO DEVELOP ABOVE LOWERING CLOUD COVER LATE TONIGHT
INTO SUNDAY MORNING. CLOUD COVER WILL LIMIT AMOUNT OF WARMING IN
THE MORNING. BY THE TIME SURFACE FRONT RETREATS NORTHWARD SUNDAY
AFTERNOON AND LOW CLOUDS START MIXING OUR...CAP WILL BE IN PLACE.
THE OLD ADAGE...NEVER TRUST A WARM FRONT...APPLIES HERE THOUGH. SO I
STILL BRING AN AXIS OF CHANCE POPS NORTHWARD WITH THE WARM FRONT
DURING THE DAY SUNDAY...ERADICATING FROM THE SOUTH DURING THE
AFTERNOON. BECAUSE OF SHALLOW WARM FRONT/CLOUD COVER...I LOWERED
TEMPERATURES SOMEWHAT FOR SUNDAY...THOUGH IT WILL STILL TURN OUT
AT LEAST A FEW TO SEVERAL DEGREES WARMER THAN TODAY /SATURDAY/.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
415 PM UPDATE...DRYING OUT WITH STRONG CAP AMIDST IMPRESSIVE WARM
SECTOR SUNDAY NIGHT. I AGAIN WENT ABOVE GUIDANCE FOR LOWS MONDAY
MORNING...WHICH WILL FEEL EERILY SUMMER-LIKE AT DAWN. THE WARM HEAD
START...850MB TEMPERATURES 2 TO 3 STANDARD DEVIATIONS ABOVE
NORMAL...AND WITH SUNSHINE FOR AT LEAST A MAJORITY OF THE
DAY...WILL YIELD HIGHS ROUGHLY 25 OR SO DEGREES ABOVE NORMAL. THIS
WILL BE WITHIN A FEW TO SEVERAL DEGREES OF RECORD DAILY
HIGHS...THOUGH ACTUALLY BREAKING THE RECORDS IS CURRENTLY NOT
FORECAST /YET/.
MODELS HAVE COME INTO GOOD AGREEMENT ON TIMING OF INCOMING FRONT
MID TO LATE AFTERNOON IN THE WESTERN CWA MONDAY...SLOWING DOWN
WHILE BECOMING MORE FLOW-PARALLEL INTO MONDAY EVENING AS IT EDGES
EASTWARD. STRONG CAP EARLY IN DAY...ERODES TO POINT OF BREAKING AS
FRONT MOVES IN. AT FIRST GLANCE...FRONT APPEARS TO TAKE ANAFRONT
NATURE...AND ACTUALLY EVENTUALLY DOES. HOWEVER...DURING THE DAY
MONDAY...CLOSER INSPECTION REVEALS THAT MOISTURE IS POOLED
IMMEDIATELY ALONG FRONT RATHER THAN BEHIND...AND THERE IS ENOUGH
INSTABILITY AND SHEAR FOR THUNDERSTORMS WHICH COULD BE GUSTY /AT
LEAST IN THE WESTERN HALF OF THE AREA/. THIS WILL BEAR WATCHING IN
COMING MODEL RUNS. FOR NOW...SPC TALKS ABOUT OUR SITUATION WITHIN
THE TEXT OF THE DAY 3 OUTLOOK...BUT NOT ENOUGH CONFIDENCE TO
INCLUDE WITHIN SLIGHT RISK FOR SEVERE. I AGREE THAT UNTIL THERE IS
HIGHER CONFIDENCE IN THE INSTABILITY/CAPE EXISTING ALONG THE
FRONT...TOO EARLY TO MENTION SEVERE POTENTIAL WITHIN THE HAZARDOUS
WEATHER OUTLOOK.
DRAMATIC TEMPERATURE FALL INBOUND FOR TUESDAY BEHIND THE
FRONT...YET ONLY BACK TO NEAR SEASONAL VALUES. COLUMN APPEARS TOO
DRY IN THE MODELS TO SUPPORT MENTIONABLE POPS...SO I TOOK WHAT
LITTLE WE HAD IN THE FORECAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
GNRLY ZONAL FLOW IS FCST IN THE MEDIUM RNG. HI PRES IS XPCTD TO BRING
FAIR WEATHER ON WED...WITH ANOTHER FNTL PSSG ON THU. LATE IN THE
PD...DEEPENING TROF MOVG INTO THE OH VLY MAY BRING UNSETTLED WX
FRI INTO SAT. NO SIG CHGS TO HPC GUIDANCE OTHER THAN BEING A BIT
MORE OPTIMISTIC ON CLD CVR TUE NGT INTO WED.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
00Z SUN UPDATE... TOUGH CALL OVERNIGHT WITH REGARDS TO PCPN.
CURRENT INDICATIONS ARE THAT MOST OF THE RAIN WILL STAY S OF OUR
TERMINALS...OTHER THAN A FEW SPRINKLES AT KELM/KAVP MAINLY. AS A
RESULT...VSBY`S SHOULD STAY UNRESTRICTED.
HOWEVER...IT STILL APPEARS THAT LWR CIGS WILL OVERSPREAD THE RGN
FROM W TO E LATER THIS EVE...THEN PERSIST TIL THE MIDDAY HRS SUN.
WE`LL BRING IN MVFR CIGS IN THE 04-07Z TIME FRAME...THEN INDICATE
SOME IMPROVEMENT BACK TO VFR IN THE 14-17Z PD SUN.
LIGHT VRBL WINDS (AOB 5 KT) OVERNIGHT...WILL BECOME SWLY BY EARLY
SUN AFTN...INCRG TO ARND 10 KT.
.OUTLOOK...
SUN NGT...VFR.
MON...VFR...BUT A BAND OF MVFR CIGS/SHRA PSBL WITH FROPA LATE MON OR
MON EVNG.
MON NGT THRU WED NGT...VFR.
THU...SCT MVFR IN -SHRA.
&&
.FIRE WEATHER...
FIRE SENSITIVE CONDITIONS AGAIN THIS AFTERNOON...WITH AREA WIDE
RELATIVE HUMIDITY WELL BELOW 30 PERCENT FOR MOST OF THE AREA...AND
GUSTS NEAR 20 MPH IN THE POCONOS. FINE FUELS CONTINUE TO REMAIN
VERY DRY RUNNING BETWEEN 5 AND 8 PERCENT. HOWEVER...FIRE THREAT
IS NOW BEING MITIGATED BY THICKENING HIGH CLOUDS THE REMAINDER OF
THE AFTERNOON...WHICH WILL LIMIT MIXING DOWN OF WINDS. WITH GUSTS
NOT EXPECTED TO CONSISTENTLY REACH CRITERIA LEVELS...NO RED FLAG
NEEDED.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...CMG/HEDEN/MDP
SHORT TERM...MDP
LONG TERM...
AVIATION...MLJ
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS TULSA OK
1245 PM CDT SUN APR 15 2012
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
SHOWERS AND THUNDERSTORMS WILL AFFECT THE ARKANSAS TAF SITES FOR
THE FIRST COUPLE HOURS OF THE FORECAST PERIOD. MVFR TO IFR
CONDITIONS MAY OCCUR IN THE STORMS. ALL SITES WILL SEE VFR
CONDITIONS BY LATE AFTERNOON WITH SKIES CLEARING OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 339 AM CDT SUN APR 15 2012/
DISCUSSION...
LARGE H5 TROUGH IS STARTING TO PIVOT EAST. MAJOR PORTION OF THE
TROUGH EJECTS TODAY...WITH REMAINDER OF TROUGH SWEEPING EAST
MONDAY AND MONDAY NIGHT. SQUALL LINE AND PSEUDO FRONT WILL PUSH
THROUGH EASTERN OK AND NORTHWEST AR TODAY. MAIN COLD FRONT/SURFACE
TROUGH WILL BE NEAR OMA-CDS LINE BY 7 PM TONIGHT...THEN SWING QUICKLY
EAST TONIGHT. NORTHWEST WINDS AND HIGH PRESSURE WILL BUILD OVER
THE AREA ON MONDAY.
NORTHWEST FLOW ALOFT WILL BRING A SHORT WAVE TROUGH THROUGH ON
WEDNESDAY...WITH SOME CLOUDINESS...BUT EXPECT NO PRECIPITATION.
TROUGH APPEARS TO MINOR OUT AS IT MOVES SOUTHEAST...AND FLOW
BECOMES NEARLY ZONAL. BETTER CHANCE OF SHOWERS OR THUNDERSTORMS
DEVELOPS ON THURSDAY AND THURSDAY NIGHT...AS H5 TROUGH DEVELOPS IN
THE FLOW AND MOVES OVER THE CENTRAL PLAINS. THE GFS AND ECMWF
TIMING ARE A LITTLE DIFFERENT...BUT BOTH SEE THIS DEVELOPMENT.
KEPT CHANCE POPS FOR THIS EVENT. MAJOR TROUGH EVENTUALLY DEVELOPS
BY NEXT WEEKEND OVER THE SOUTHEAST STATES...PUTTING OK IN NORTHWEST
FLOW.
TIMING OF PRECIPITATION THIS MORNING AND LATER TODAY IS THE
PRIMARY ISSUE. ANTICIPATE THE LINE OF STORMS TO BE FROM ABOUT
NOWATA TO TULSA TO OKEMAH AROUND 6-7 AM. THE PRECIPITATION SHOULD
REACH NORTHWEST ARKANSAS BY MID TO LATE MORNING. EXPECT THE
EXISTING LINE TO CARRY ALL THE PRECIPITATION...AND SIGNIFICANTLY
LOWERED OR DROPPED POPS BEHIND THE LINE.
GENERALLY STAYED CLOSE TO MAV/MEX MOS GUIDANCE FOR TEMPS...WITH
MINOR ADJUSTMENT TO ECMWF IN A COUPLE OF PERIODS.
WIND GUSTS ARE BECOMING MORE ISOLATED AND LATEST RUC RELAXES
SURFACE PRESSURE GRADIENT...SO WILL DROP THE WIND ADVISORY.
STILL...THERE WILL BE FREQUENT GUSTS OVER 30 MPH UNTIL THE LINE OF
STORMS MOVES THROUGH.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...05
AREA FORECAST DISCUSSION
NWS TULSA OK
339 AM CDT SUN APR 15 2012
.DISCUSSION...
LARGE H5 TROUGH IS STARTING TO PIVOT EAST. MAJOR PORTION OF THE
TROUGH EJECTS TODAY...WITH REMAINDER OF TROUGH SWEEPING EAST
MONDAY AND MONDAY NIGHT. SQUALL LINE AND PSEUDO FRONT WILL PUSH
THROUGH EASTERN OK AND NORTHWEST AR TODAY. MAIN COLD FRONT/SURFACE
TROUGH WILL BE NEAR OMA-CDS LINE BY 7 PM TONIGHT...THEN SWING QUICKLY
EAST TONIGHT. NORTHWEST WINDS AND HIGH PRESSURE WILL BUILD OVER
THE AREA ON MONDAY.
NORTHWEST FLOW ALOFT WILL BRING A SHORT WAVE TROUGH THROUGH ON
WEDNESDAY...WITH SOME CLOUDINESS...BUT EXPECT NO PRECIPITATION.
TROUGH APPEARS TO MINOR OUT AS IT MOVES SOUTHEAST...AND FLOW
BECOMES NEARLY ZONAL. BETTER CHANCE OF SHOWERS OR THUNDERSTORMS
DEVELOPS ON THURSDAY AND THURSDAY NIGHT...AS H5 TROUGH DEVELOPS IN
THE FLOW AND MOVES OVER THE CENTRAL PLAINS. THE GFS AND ECMWF
TIMING ARE A LITTLE DIFFERENT...BUT BOTH SEE THIS DEVELOPMENT.
KEPT CHANCE POPS FOR THIS EVENT. MAJOR TROUGH EVENTUALLY DEVELOPS
BY NEXT WEEKEND OVER THE SOUTHEAST STATES...PUTTING OK IN NORTHWEST
FLOW.
TIMING OF PRECIPITATION THIS MORNING AND LATER TODAY IS THE
PRIMARY ISSUE. ANTICIPATE THE LINE OF STORMS TO BE FROM ABOUT
NOWATA TO TULSA TO OKEMAH AROUND 6-7 AM. THE PRECIPITATION SHOULD
REACH NORTHWEST ARKANSAS BY MID TO LATE MORNING. EXPECT THE
EXISTING LINE TO CARRY ALL THE PRECIPITATION...AND SIGNIFICANTLY
LOWERED OR DROPPED POPS BEHIND THE LINE.
GENERALLY STAYED CLOSE TO MAV/MEX MOS GUIDANCE FOR TEMPS...WITH
MINOR ADJUSTMENT TO ECMWF IN A COUPLE OF PERIODS.
WIND GUSTS ARE BECOMING MORE ISOLATED AND LATEST RUC RELAXES
SURFACE PRESSURE GRADIENT...SO WILL DROP THE WIND ADVISORY.
STILL...THERE WILL BE FREQUENT GUSTS OVER 30 MPH UNTIL THE LINE OF
STORMS MOVES THROUGH.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 77 47 72 49 / 50 10 0 10
FSM 79 50 72 48 / 80 10 10 10
MLC 78 47 74 47 / 70 10 0 10
BVO 72 46 72 43 / 30 20 0 10
FYV 71 45 69 42 / 80 20 0 10
BYV 73 46 68 46 / 80 20 10 10
MKO 75 47 74 47 / 70 10 10 10
MIO 76 46 70 46 / 70 20 0 10
F10 76 48 72 50 / 60 10 0 0
HHW 77 49 75 50 / 70 10 0 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...WIND ADVISORY UNTIL 4 AM SUNDAY FOR OKZ054-OKZ055-OKZ059-OKZ060-
OKZ064-OKZ065-OKZ066.
AR...NONE.
&&
$$
SHORT TERM...22
LONG TERM....02
AREA FORECAST DISCUSSION
NWS TULSA OK
104 AM CDT SUN APR 15 2012
...MESOSCALE UPDATE...
.DISCUSSION...
SURFACE PRESSURE GRADIENT HAS TIGHTENED AND IS SUPPORTING FREQUENT
GUSTS OVER 40 MPH OVER THE AREA GENERALLY WEST OF HIGHWAY 75.
THESE ARE EVIDENT FROM THE OK MESONET DATA. THERE ARE A COUPLE OF
MESONET DATA FARTHER SOUTH TOWARD MCALESTER THAT HAVE GUSTED TO 41
AND 43 MPH...BUT FEEL THESE ARE OUTLIERS AND WILL NOT LAST. WILL
KNOW FOR SURE IN A COUPLE OF HOURS.
KEPT THE ADVISORY UP UNTIL THE 4 AM FORECASTS GO OUT. BY THAT
TIME...THE RUC RELAXES THE GRADIENT...PROBABLY IN RESPONSE TO THE
FRONT GETTING CLOSER. SHOULD BE ABLE TO DROP THE ADVISORY AT 4
AM...BUT WILL LIKELY BE MONITORING OTHER METEOROLOGICAL EVENTS BY
THAT TIME...
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...WIND ADVISORY UNTIL 4 AM SUNDAY FOR OKZ054-OKZ055-OKZ059-OKZ060-
OKZ064-OKZ065-OKZ066.
AR...NONE.
&&
$$
LONG TERM....02
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1055 PM CDT MON APR 16 2012
.DISCUSSION.../ISSUED AT 948 PM CDT/
FROST ADVISORY IS AREA OF MAIN CONCERN TONIGHT. CLOUDS A LITTLE
SLOWER TO CLEAR THUS FAR OVER NORTHERN PORTIONS OF THE CWA...AND
UPDATED EARLIER TO HANG ONTO THE CLOUD COVER IN THE NORTHEAST UNTIL
CLOSER TO MIDNIGHT. LATEST NAM AND RUC DO STILL SHOW THIS MOISTURE
LAYER DIMINISHING OVERNIGHT THOUGH...AS THE SURFACE RIDGE SLIDES
EAST...SO WILL CONTINUE WITH CLEARING TREND ACROSS THE NORTH...WITH
SOME INCREASE IN CLOUDS IN THE SOUTH AS MID LEVEL DECK WEST OF THE
MISSOURI RIVER SHIFTS EASTWARD. LIGHT WINDS SHOULD ACCOMPANY THE
CLEARING...ALLOWING TEMPERATURES TO FALL INTO THE LOWER TO MID 30S
AS FORECAST. WITH MORE LOW LEVEL MOISTURE PRESENT THAN WITH THE
COLD SNAP EARLIER THIS MONTH...AREAS OF FROST ARE A POSSIBILITY.
MAIN FROST THREAT MORE LIKELY IN LOW LYING/SHELTERED AREAS...AS
SURFACE RIDGE SHIFTS EAST OF CWA QUICKLY ENOUGH TO ALLOW FOR 5-7KT
RETURN FLOW TO SET UP IN MORE OPEN AREAS BY LATE TONIGHT. BUT WILL
LET THE ADVISORY RIDE FOR THE LATE NIGHT/EARLY MORNING HOURS AND
HIGHLIGHT SHELTERED AREAS FOR GREATER LIKELIHOOD.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
VFR LOOKS GOOD THROUGH 18/00Z. WITH LIGHT SOUTHEAST FLOW DEVELOPING
TONIGHT COOLING SEEMS TO SHALLOW FOR ANY FOG. ISOLATED CONVECTION
POSSIBLE 18Z-18/00Z BUT ANY LOWERING TO MVFR VERY UNCERTAIN AND
WOULD BE SO BRIEF AND CONFINED TO SUCH A SMALL AREA THAT IT WILL NOT
BE MENTIONED IN TAFS. 18/00Z-06Z WILL LIKELY SEE MORE SCATTERED
SHOWERS AND THUNDERSTORMS WITH BRIEF AND ISOLATED LOWERING OF
CEILINGS TO 3K FEET AND VISIBILITIES TO 3-5SM...STILL VFR LIKELY TO
BE PREVAILING.
&&
.PREV DISCUSSION.../ISSUED AT 355 PM CDT/
EXPECT CLOUDS TO BEGIN TO DIMINISH TONIGHT OVER MUCH OF THE AREA.
HIGH PRESSURE BUILDING IN OVERHEAD WILL ALLOW WINDS TO BECOME ALMOST
CALM FOR A PERIOD AS WELL. THIS COMBINATION SHOULD ALLOW FOR GOOD
RADIATIONAL COOLING OVER MUCH OF THE AREA. THE EXCEPTION MAY BE
CLOSER TO THE MISSOURI RIVER VALLEY...WHERE MODELS HINTING AT SOME
MID LEVEL CLOUDINESS HANGING AROUND. FOLLOWED CLOSE TO THE COOLER
GUIDANCE TONIGHT WHERE SKIES ARE EXPECTED TO BE CLEAR...AND MORE
TOWARDS CONSENSUS VALUES FURTHER SOUTH WHERE CLOUDS MAY LINGER. THIS
GIVES LOWS AROUND FREEZING IN THE NORTH...AND IN THE UPPER 30S
FURTHER SOUTH. WITH MOIST GROUND...THINK FROST WILL FORM WHERE
TEMPERATURES APPROACH FREEZING TONIGHT. MAY ALSO SEE SOME FOG FORM
IN THIS SAME AREA. THE ONE CAVEAT IS IF CLOUDS LINGER OR IF WINDS
PICK UP A BIT OUT OF THE SOUTH LATER TONIGHT. BUT FEEL THAT THESE
ARE LESS LIKELY EVENTS...SO WENT WITH THE FROST ADVISORY GENERALLY
NORTH OF INTERSTATE 90 AND INTO PORTIONS OF NORTHWEST IOWA.
TUESDAY LOOKS LIKE A WARM DAY ACROSS THE REGION. ANY MORNING CLOUDS
SHOULD GIVE WAY TO AT LEAST PARTLY SUNNY SKIES BY AFTERNOON. 925MB
TEMPERATURES SURGE TO NEAR 22C WEST OF THE JAMES RIVER BY
AFTERNOON...AND INTO THE MID TEENS FAR EAST. THIS WOULD SUPPORT
HIGHS AT LEAST MID 70S WEST AND MID TO UPPER 60S EAST. THUS RAISED
HIGHS A FEW DEGREES. INCREASING CLOUDS AHEAD OF OUR NEXT SHORTWAVE
ARE THE ONLY THING THAT MIGHT PREVENT HIGHS FROM REACHING THIS
HIGH...BUT THINK CLOUDS COVER WILL BE THIN ENOUGH AND SLOW TO
INCREASE. THIS WENT WITH HIGHS CLOSER TO THE WARMER GUIDANCE. SOME
WEAK INSTABILITY SHOULD DEVELOP ACROSS PORTIONS OF SOUTHWEST
MINNESOTA AND NORTHWEST IOWA LATE TOMORROW...WITH AROUND 500 J/KG
POSSIBLE. IF WE CAN GET WARM ENOUGH...WE MAY BE ABLE TO BREAK THE
CAP AND GET A FEW SHOWERS AND THUNDERSTORMS THERE. ONLY WENT SLIGHT
CHANCE...AS THINK COVERAGE WILL BE ISOLATED AT BEST THROUGH 0Z. ANY
STORM THAT DOES FORM SHOULD BE ON THE WEAK SIDE GIVEN THE MARGINAL
INSTABILITY. /CHENARD
ON TUESDAY NIGHT...THE CRUX OF THE NEXT FAST MOVING MID AND UPPER
WAVE MOVES EASTWARD THROUGH THE ZONAL FLOW. CLEARLY THE STRONG
DYNAMICS ARE TO THE NORTH OF THIS FORECAST AREA...AS EVIDENCED BY
THE PV AND QG FORCING. AHEAD OF THE WAVE IN THE EARLY EVENING...
THERE IS ENOUGH ENHANCE FORCING FROM LOW LEVEL WARM AIR ADVECTION IN
NW IA AND SW MN THAT SOME THUNDERSTORMS MAY DEVELOP. THESE WILL BE
AIDED BY MODEST MLCAPE VALUES THAT MAY HELP TO SUSTAIN SOME
UPDRAFTS. THIS ACTIVITY WILL LIKELY RAPIDLY WIND DOWN AFTER SUNSET.
BUT THEN THE SHORT WAVE ITSELF BEGINS TO TAKEOVER PRODUCING SHOWER
AND THUNDERSTORM CHANCES...WITH ELEVATED INSTABILITY...MOVING FROM
WEST TO EAST THROUGH THE NIGHT. AT THIS TIME...THERE IS NOT ENOUGH
MOISTURE SUPPORT TO GO LIKELY...EVEN IN OUR NORTHERN ZONES. LOW
TEMPERATURES SHOULD VARY FROM THE LOWER 40S IN OUR FAR WEST BEHIND
THE SURFACE WIND SHIFT AND CLEARING...TO THE LOWER 50S IN NORTHWEST
IA.
ON WEDNESDAY...HIGH PRESSURE FROM SOUTH CENTRAL CANADA BRINGS DOWN
FLOW FROM THE NORTH BUT TEMPERATURES DUE TO A WELL MIXED ATMOSPHERE
SHOULD STILL BE MILD. THE NEXT WAVE THEN MOVES INTO THIS AREA
WEDNESDAY NIGHT...DIGS A LITTLE IN THE CENTRAL PLAINS...THEN EXITS
LATE THURSDAY. THIS WAVE IS FURTHER SOUTH THEN TUESDAY NIGHTS WAVE
AND WILL LIKELY IMPACT THIS FORECAST AREA MORE. FOR NOW...CONTINUED
TO LEAVE THE MENTION OF THUNDER OUT OF THE FORECAST WEDNESDAY NIGHT
AND THURSDAY AS THE LAPSE RATES DO NOT SUPPORT CONVECTION. PLACED A
BAND OF LIKELY POPS THROUGH MOST OF THE NORTHERN HALF OF THE
FORECAST AREA RIGHT ALONG THE MID LEVEL CONVERGENCE AS THE LOW LEVEL
FLOW REMAINS OUT OF THE NORTHEAST. BECAUSE OF THE NORTHEAST FLOW...
THURSDAY WILL BE A NOT SO PLEASANT DAY...WITH CLOUD COVER AND
PROBABLE RAINFALL HOLDING TEMPERATURES DOWN IN THE UPPER 40S AND
50S.
NOT MANY CHANGES NEEDED TO THE EXTENDED. STILL LOOKS ON TARGET FOR A
POSSIBLE LIGHT RAINFALL EVENT FRIDAY AND FRIDAY NIGHT...ESPECIALLY
IN THE NORTHERN HALF OF THE AREA.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...FROST ADVISORY FROM 4 AM TO 8 AM CDT TUESDAY FOR IAZ001>003-
012>014.
MN...FROST ADVISORY FROM 4 AM TO 8 AM CDT TUESDAY FOR MNZ071-072-080-
081-089-090-097-098.
NE...NONE.
SD...FROST ADVISORY FROM 4 AM TO 8 AM CDT TUESDAY FOR SDZ038>040-
052>062-067.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
948 PM CDT MON APR 16 2012
.DISCUSSION.../ISSUED AT 948 PM CDT/
FROST ADVISORY IS AREA OF MAIN CONCERN TONIGHT. CLOUDS A LITTLE
SLOWER TO CLEAR THUS FAR OVER NORTHERN PORTIONS OF THE CWA...AND
UPDATED EARLIER TO HANG ONTO THE CLOUD COVER IN THE NORTHEAST UNTIL
CLOSER TO MIDNIGHT. LATEST NAM AND RUC DO STILL SHOW THIS MOISTURE
LAYER DIMINISHING OVERNIGHT THOUGH...AS THE SURFACE RIDGE SLIDES
EAST...SO WILL CONTINUE WITH CLEARING TREND ACROSS THE NORTH...WITH
SOME INCREASE IN CLOUDS IN THE SOUTH AS MID LEVEL DECK WEST OF THE
MISSOURI RIVER SHIFTS EASTWARD. LIGHT WINDS SHOULD ACCOMPANY THE
CLEARING...ALLOWING TEMPERATURES TO FALL INTO THE LOWER TO MID 30S
AS FORECAST. WITH MORE LOW LEVEL MOISTURE PRESENT THAN WITH THE
COLD SNAP EARLIER THIS MONTH...AREAS OF FROST ARE A POSSIBILITY.
MAIN FROST THREAT MORE LIKELY IN LOW LYING/SHELTERED AREAS...AS
SURFACE RIDGE SHIFTS EAST OF CWA QUICKLY ENOUGH TO ALLOW FOR 5-7KT
RETURN FLOW TO SET UP IN MORE OPEN AREAS BY LATE TONIGHT. BUT WILL
LET THE ADVISORY RIDE FOR THE LATE NIGHT/EARLY MORNING HOURS AND
HIGHLIGHT SHELTERED AREAS FOR GREATER LIKELIHOOD.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
A FEW CEILINGS 2-3K FEET FAR EASTERN PART OF AREA EAST OF TAF SITES
UNTIL 03Z OTHERWISE GENERALLY VFR THROUGH 18/00Z WITH AREAS OF
CLOUDS ABOVE 5K FEET AGL. ISOLATED SHOWERS OR THUNDERSTORMS MAY
DEVELOP AFTER 18Z BUT THREAT AND COVERAGE TOO LOW TO PUT IN CURRENT
TAFS. SURFACE GUSTS FROM THE SOUTH MAY APPROACH 25 KNOTS AFTER 18Z
SOUTHEAST PART OF AREA INCLUDING KSUX.
&&
.PREV DISCUSSION.../ISSUED AT 355 PM CDT/
EXPECT CLOUDS TO BEGIN TO DIMINISH TONIGHT OVER MUCH OF THE AREA.
HIGH PRESSURE BUILDING IN OVERHEAD WILL ALLOW WINDS TO BECOME ALMOST
CALM FOR A PERIOD AS WELL. THIS COMBINATION SHOULD ALLOW FOR GOOD
RADIATIONAL COOLING OVER MUCH OF THE AREA. THE EXCEPTION MAY BE
CLOSER TO THE MISSOURI RIVER VALLEY...WHERE MODELS HINTING AT SOME
MID LEVEL CLOUDINESS HANGING AROUND. FOLLOWED CLOSE TO THE COOLER
GUIDANCE TONIGHT WHERE SKIES ARE EXPECTED TO BE CLEAR...AND MORE
TOWARDS CONSENSUS VALUES FURTHER SOUTH WHERE CLOUDS MAY LINGER. THIS
GIVES LOWS AROUND FREEZING IN THE NORTH...AND IN THE UPPER 30S
FURTHER SOUTH. WITH MOIST GROUND...THINK FROST WILL FORM WHERE
TEMPERATURES APPROACH FREEZING TONIGHT. MAY ALSO SEE SOME FOG FORM
IN THIS SAME AREA. THE ONE CAVEAT IS IF CLOUDS LINGER OR IF WINDS
PICK UP A BIT OUT OF THE SOUTH LATER TONIGHT. BUT FEEL THAT THESE
ARE LESS LIKELY EVENTS...SO WENT WITH THE FROST ADVISORY GENERALLY
NORTH OF INTERSTATE 90 AND INTO PORTIONS OF NORTHWEST IOWA.
TUESDAY LOOKS LIKE A WARM DAY ACROSS THE REGION. ANY MORNING CLOUDS
SHOULD GIVE WAY TO AT LEAST PARTLY SUNNY SKIES BY AFTERNOON. 925MB
TEMPERATURES SURGE TO NEAR 22C WEST OF THE JAMES RIVER BY
AFTERNOON...AND INTO THE MID TEENS FAR EAST. THIS WOULD SUPPORT
HIGHS AT LEAST MID 70S WEST AND MID TO UPPER 60S EAST. THUS RAISED
HIGHS A FEW DEGREES. INCREASING CLOUDS AHEAD OF OUR NEXT SHORTWAVE
ARE THE ONLY THING THAT MIGHT PREVENT HIGHS FROM REACHING THIS
HIGH...BUT THINK CLOUDS COVER WILL BE THIN ENOUGH AND SLOW TO
INCREASE. THIS WENT WITH HIGHS CLOSER TO THE WARMER GUIDANCE. SOME
WEAK INSTABILITY SHOULD DEVELOP ACROSS PORTIONS OF SOUTHWEST
MINNESOTA AND NORTHWEST IOWA LATE TOMORROW...WITH AROUND 500 J/KG
POSSIBLE. IF WE CAN GET WARM ENOUGH...WE MAY BE ABLE TO BREAK THE
CAP AND GET A FEW SHOWERS AND THUNDERSTORMS THERE. ONLY WENT SLIGHT
CHANCE...AS THINK COVERAGE WILL BE ISOLATED AT BEST THROUGH 0Z. ANY
STORM THAT DOES FORM SHOULD BE ON THE WEAK SIDE GIVEN THE MARGINAL
INSTABILITY. /CHENARD
ON TUESDAY NIGHT...THE CRUX OF THE NEXT FAST MOVING MID AND UPPER
WAVE MOVES EASTWARD THROUGH THE ZONAL FLOW. CLEARLY THE STRONG
DYNAMICS ARE TO THE NORTH OF THIS FORECAST AREA...AS EVIDENCED BY
THE PV AND QG FORCING. AHEAD OF THE WAVE IN THE EARLY EVENING...
THERE IS ENOUGH ENHANCE FORCING FROM LOW LEVEL WARM AIR ADVECTION IN
NW IA AND SW MN THAT SOME THUNDERSTORMS MAY DEVELOP. THESE WILL BE
AIDED BY MODEST MLCAPE VALUES THAT MAY HELP TO SUSTAIN SOME
UPDRAFTS. THIS ACTIVITY WILL LIKELY RAPIDLY WIND DOWN AFTER SUNSET.
BUT THEN THE SHORT WAVE ITSELF BEGINS TO TAKEOVER PRODUCING SHOWER
AND THUNDERSTORM CHANCES...WITH ELEVATED INSTABILITY...MOVING FROM
WEST TO EAST THROUGH THE NIGHT. AT THIS TIME...THERE IS NOT ENOUGH
MOISTURE SUPPORT TO GO LIKELY...EVEN IN OUR NORTHERN ZONES. LOW
TEMPERATURES SHOULD VARY FROM THE LOWER 40S IN OUR FAR WEST BEHIND
THE SURFACE WIND SHIFT AND CLEARING...TO THE LOWER 50S IN NORTHWEST
IA.
ON WEDNESDAY...HIGH PRESSURE FROM SOUTH CENTRAL CANADA BRINGS DOWN
FLOW FROM THE NORTH BUT TEMPERATURES DUE TO A WELL MIXED ATMOSPHERE
SHOULD STILL BE MILD. THE NEXT WAVE THEN MOVES INTO THIS AREA
WEDNESDAY NIGHT...DIGS A LITTLE IN THE CENTRAL PLAINS...THEN EXITS
LATE THURSDAY. THIS WAVE IS FURTHER SOUTH THEN TUESDAY NIGHTS WAVE
AND WILL LIKELY IMPACT THIS FORECAST AREA MORE. FOR NOW...CONTINUED
TO LEAVE THE MENTION OF THUNDER OUT OF THE FORECAST WEDNESDAY NIGHT
AND THURSDAY AS THE LAPSE RATES DO NOT SUPPORT CONVECTION. PLACED A
BAND OF LIKELY POPS THROUGH MOST OF THE NORTHERN HALF OF THE
FORECAST AREA RIGHT ALONG THE MID LEVEL CONVERGENCE AS THE LOW LEVEL
FLOW REMAINS OUT OF THE NORTHEAST. BECAUSE OF THE NORTHEAST FLOW...
THURSDAY WILL BE A NOT SO PLEASANT DAY...WITH CLOUD COVER AND
PROBABLE RAINFALL HOLDING TEMPERATURES DOWN IN THE UPPER 40S AND
50S.
NOT MANY CHANGES NEEDED TO THE EXTENDED. STILL LOOKS ON TARGET FOR A
POSSIBLE LIGHT RAINFALL EVENT FRIDAY AND FRIDAY NIGHT...ESPECIALLY
IN THE NORTHERN HALF OF THE AREA.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...FROST ADVISORY FROM 4 AM TO 8 AM CDT TUESDAY FOR IAZ001>003-
012>014.
MN...FROST ADVISORY FROM 4 AM TO 8 AM CDT TUESDAY FOR MNZ071-072-080-
081-089-090-097-098.
NE...NONE.
SD...FROST ADVISORY FROM 4 AM TO 8 AM CDT TUESDAY FOR SDZ038>040-
052>062-067.
&&
$$
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
327 PM CDT SUN APR 15 2012
.DISCUSSION...
THE SFC FRONT IS SLOWLY WORKING ITS WAY INTO THE COASTAL
PLAINS...WITH SCATTERED CONVECTION CONTINUING ALONG THE FRONTAL
BOUNDARY. THE FRONT IS EXPECTED TO STALL ALONG THE COAST LATER
TONIGHT...WITH GOOD CONSENSUS AMONG THE NAM/GFS OF POST-FRONTAL
PRECIPITATION CONTINUING ACROSS OUR SOUTHERN COUNTIES.
HOWEVER...THE 18Z RUC AND 12Z HI-RES BOTH INDICATE THE PRECIP AXIS
WILL SHIFT COMPLETELY SOUTH OF OUR CWA THIS EVENING. HAVE SOMEWHAT
SPLIT THE DIFFERENCE AND KEPT TOKEN POPS ACROSS OUR SOUTHEASTERN
TIER OF COUNTIES FOR THIS EVENING.
AS THE FRONT STALLS ALONG THE COAST OVERNIGHT...THE MID-UPPER
LEVEL TROUGH AXIS WILL REMAIN NORTHWEST OF OUR AREA. THEREFORE
SOME POST-FRONTAL SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP
ACROSS THE SOUTHEASTERN HALF OF THE REGION TOMORROW AND INTO
TOMORROW NIGHT. RAIN CHANCES WILL CLEAR THE AREA ON TUESDAY AS THE
UPPER TROUGH AXIS SLIDES TO THE EAST OF THE REGION AND DRIER NW
FLOW ALOFT SETTLES INTO THE AREA. MOSTLY DRY AND SEASONABLE
CONDITIONS WILL PREVAIL THROUGH THE MIDDLE OF THE WEEK WITH
ONSHORE FLOW RETURNING LATE TUESDAY/EARLY WEDS. THE INCREASING LOW
LEVEL MOISTURE WILL RESULT IN A SLOW WARMING TREND THROUGH THE END
OF THE WEEK.
MID/LONG-RANGE MODELS CONTINUE TO HAVE FAIR CONSENSUS ON AN UPPER
TROUGH/COLD FRONT FOR OUR AREA LATE IN THE WEEK. CURRENT THINKING
IS THAT THE BEST TIME-FRAME FOR RAIN WOULD BE FRI AFTERNOON/NIGHT.
HOWEVER...THIS COULD EASILY SHIFT TO A FRI NIGHT/SAT MORNING OR
LATER SCENARIO GIVEN WE`RE TALKING ABOUT 126-PLUS HRS FROM NOW.
&&
.FIRE WEATHER...
ELEVATED TO NEAR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED
ACROSS THE SOUTHERN EDWARDS PLATEAU AND RIO GRANDE PLAINS THROUGH
THIS EVENING IN THE WAKE OF THE COLD FRONT. LOW RELATIVE HUMIDITIES
AND GUSTY NORTHWEST WINDS NEAR 15 MPH WILL CONTINUE THROUGH THE
REMAINDER OF THE AFTERNOON WITH WINDS DECREASING TO 10 TO 15 MPH
AFTER SUNSET. RH VALUES WILL BE SLOWER TO RECOVER. ELEVATED FIRE
WEATHER CONDITIONS ARE EXPECTED ACROSS WESTERN AREAS ON MONDAY
AFTERNOON MAINLY DUE TO LOW HUMIDITIES AS WINDS WILL BE AT OR
BELOW 10 MPH.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 54 81 57 82 60 / - 20 10 - -
AUSTIN BERGSTROM INTL AIRPORT 52 81 55 82 56 / - 20 10 - -
NEW BRAUNFELS MUNI AIRPORT 52 80 56 81 57 / - 20 10 - -
BURNET MUNI AIRPORT 49 78 52 80 55 / - - - 0 -
DEL RIO INTL AIRPORT 51 84 57 86 63 / - - - 0 -
GEORGETOWN MUNI AIRPORT 49 79 51 81 56 / - 10 10 - -
HONDO MUNI AIRPORT 50 81 55 84 58 / - 20 10 0 -
SAN MARCOS MUNI AIRPORT 53 80 57 81 58 / - 20 10 - -
LA GRANGE - FAYETTE REGIONAL 60 80 60 80 60 / 20 40 30 10 -
SAN ANTONIO INTL AIRPORT 54 81 58 82 60 / - 20 10 - -
STINSON MUNI AIRPORT 55 81 60 83 60 / - 20 10 - -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...08
SYNOPTIC/GRIDS...25
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
631 PM CDT MON APR 16 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
319 PM CDT MON APR 16 2012
MAIN FORECAST CONCERNS ARE ON FREEZE TONIGHT AND PRECIPITATION
CHANCES FOR TUESDAY NIGHT...WEDNESDAY AND AGAIN THURSDAY.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S....TROUGHING FROM ONTARIO INTO
TEXAS AND RIDGING ALONG THE EAST COAST OF THE U.S.. WITHIN THE
TROUGHING...A POTENT SHORTWAVE TROUGH WAS OVER UPPER MICHIGAN WHICH
HAS BEEN RESPONSIBLE FOR THE WINDY CONDITIONS LATELY...WHILE ANOTHER
SHORTWAVE WAS NEAR SIOUX FALLS SOUTH DAKOTA. THIS LATTER SHORTWAVE
WAS NOT DOING MUCH PRECIPITATION WISE...BUT THERE IS A DEFINITE BAND
OF LOW TO MID LEVEL CLOUDS COVERING MUCH OF THE DAKOTAS INTO
SOUTHWEST MINNESOTA. 12Z BIS SOUNDING WAS NEARLY SATURATED FROM 925
TO 700MB...SO THE SHORTWAVE DOES APPEAR TO BE SPREADING AT LEAST
CLOUDS EASTWARD. AHEAD OF THESE CLOUDS AND IN THE WAKE OF THE POTENT
TROUGH...THERE IS SOME CLEARING DROPPING DOWN THROUGH NORTHERN AND
CENTRAL MINNESOTA. WINDS ARE SLOWLY DIMINISHING ACROSS THE AREA DUE
TO A WEAKENING PRESSURE GRADIENT. SURFACE PRESSURE ANALYSIS SHOWED A
997MB LOW WAS LOCATED OVER THE EASTERN UPPER PENINSULA WHILE A RIDGE
OF HIGH PRESSURE WAS OVER THE DAKOTAS. THE WINDY NORTHWEST WINDS
HAVE DROPPED 850MB TEMPS DOWN TO -4 TO -8C OVER THE FORECAST AREA
PER RUC ANALYSIS...AND -10 TO -12C OVER NORTHERN WISCONSIN. THIS
COLD AIR LED TO SOME STRAIGHT SNOW OR RAIN/SNOW MIX OVER NORTHERN
PORTIONS OF THE FORECAST AREA THIS MORNING. 850MB TEMPS NOT MUCH
WARMER OVER THE DAKOTAS EITHER...-2 TO -6C...CONFIRMED TOO BY 12Z
RAOBS.
TONIGHT AND TUESDAY...UPPER LEVEL FLOW IS PROGGED TO BECOME MORE
ZONAL DURING THIS PERIOD AS A SHORTWAVE OFF THE PACIFIC NORTHWEST
COAST PLOWS INLAND ACROSS THE NORTHERN ROCKIES. FOR OUR AREA...WE
WILL HAVE A FEW SHORTWAVES MOVE THROUGH...THE FIRST OF WHICH IS THE
ONE NEAR SIOUX FALLS CROSSING THIS EVENING...THEN ANOTHER MUCH
WEAKER ONE SEEN ON WATER VAPOR OVER EASTERN MONTANA WHICH COMES
THROUGH TUESDAY MORNING. AGAIN...NOT ANTICIPATING ANY PRECIPITATION
WITH EITHER SHORTWAVE BECAUSE OF A LACK OF BOTH DYNAMICAL AND
ISENTROPIC LIFT. THEY WILL...HOWEVER...BRING AN INCREASE OF LOW TO
MID LEVEL STRATUS. SO AFTER WHAT COULD BE A BRIEF PERIOD OF CLEARING
THIS EVENING...MAINLY NORTH OF I-94 ASSOCIATED WITH THAT CLEARING
DROPPING DOWN THROUGH CENTRAL MINNESOTA...EXPECTING SKIES TO AT
LEAST TURN MOSTLY CLOUDY. LIKELY THE STRATUS SHOULD CLEAR OUT IN THE
WAKE OF THE SECOND SHORTWAVE...BUT THIS APPEARS BRIEF AS WELL.
LOOKING AT TUESDAY AFTERNOON...290-300 K ISENTROPIC LIFT REALLY
INCREASES DOWNSTREAM OF THAT SHORTWAVE COMING INTO THE ROCKIES...
RESULTING IN MORE MID LEVEL STRATUS. LIFT DOES NOT LOOK STRONG
ENOUGH TO PRODUCE PRECIPITATION...THOUGH. ALL OF THESE CLOUD
TRANSITIONS MAKE THE TEMPERATURE FORECAST DIFFICULT. IF IT WERE
CLEAR TONIGHT...THE SURFACE RIDGE MOVING IN AND HAVING 850MB TEMPS
IN THE 0 TO -6C RANGE IN PLACE WOULD BE VERY FAVORABLE FOR
TEMPERATURES TO PLUMMET WELL BELOW FREEZING. WITH THE CLOUDS MOVING
THROUGH TONIGHT...GENERALLY FOLLOWED CLOSE TO A BLEND OF THE 16.12Z
NAM12/16.09Z SREF MEAN. THE LOWS PROMPT THE NEED FOR A FREEZE
WARNING ALONG/NORTH OF I-94. LOWS MAY DIP TO FREEZING
ELSEWHERE...SUCH AS LA CROSSE...BUT CONFIDENCE IS NOT HIGH ENOUGH TO
ISSUE FREEZE WARNING DUE TO THE CLOUDS. FOR TUESDAY...RETURN FLOW
DOES HELP TO BOOST 850MB TEMPS UP TO 2-6C BY 00Z WEDNESDAY...BUT
TEMPERATURES WILL BE HELD BACK SOMEWHAT DUE TO THE CLOUDS. FOLLOWED
GENERALLY A BLEND OF GUIDANCE FOR HIGHS.
TUESDAY NIGHT AND WEDNESDAY...FOCUS IS ON THAT SHORTWAVE COMING OUT
OF THE ROCKIES. VERY GOOD MODEL AGREEMENT EXISTS THAT AS THE
SHORTWAVE CROSSES THE DAKOTAS AND LIFTS INTO FAR NORTHERN WISCONSIN
WEDNESDAY MORNING...IT WILL DEEPEN. IN RESPONSE TO THIS DEEPENING...
A STRONG SURGE OF SOUTHWEST 850MB MOISTURE TRANSPORT/ISENTROPIC LIFT
ON THE 290-295K SURFACE COMES ACROSS THE AREA TUESDAY EVENING.
SHOULD SEE SOME SHOWERS FALL IN THE EVENING. THERE IS SOME WEAK
CAPE...LESS THAN 200 J/KG...ENOUGH TO WARRANT A THUNDER MENTION.
AFTER MIDNIGHT INTO WEDNESDAY MORNING...THE COMBINATION OF HEIGHT
FALLS ALOFT WITH THE APPROACHING SHORTWAVE AND A PERSISTENT FLOW OF
850MB MOISTURE TRANSPORT SHOULD LEAD TO THE DEVELOPMENT OF A WARM
CONVEYOR BELT OF SHOWERS AND EMBEDDED THUNDERSTORMS. GIVEN DECENT
COVERAGE OF PRECIPITATION DEVELOPMENT...CAPE SHOULD STAY LIMITED AT
LESS THAN 500 J/KG...LIMITING ANY CHANCE FOR SEVERE WEATHER. THIS
WARM CONVEYOR BELT WILL TRACK WEST TO EAST ACROSS THE AREA THROUGH
WEDNESDAY MORNING. GIVEN GOOD MODEL CONSENSUS FOR PRECIPITATION...
HAVE RAISED PRECIPITATION CHANCES UP TO 80 PERCENT. A DRY SLOT THEN
ENTERS THE PICTURE FOR LATE WEDNESDAY MORNING INTO THE AFTERNOON...
PUNCHING IN FROM THE WEST IN THE WAKE OF THE SHORTWAVE TROUGH
LIFTING OFF TO THE NORTHEAST. THIS DRY SLOT SHOULD END PRECIPITATION
AND LIKELY RESULT IN A DECREASE IN CLOUDS. MUCH WARMER CONDITIONS
ANTICIPATED TUESDAY NIGHT WITH LOWS IN THE EVENING...THEN CLIMBING
SLIGHTLY AFTER MIDNIGHT WITH THE MOISTURE TRANSPORT SURGE. WARMER
850MB TEMPS OF 4-8C ON WEDNESDAY...PLUS SUN...WILL ALLOW FOR HIGHS
IN THE 60S TO EVEN 70.
WEDNESDAY NIGHT AND THURSDAY...THIS PERIOD FOCUS IS ON A COLLECTIONS
OF SHORTWAVES PROGGED TO MOVE INTO THE NORTHERN ROCKIES LATE
WEDNESDAY. HEIGHT FALLS DOWNSTREAM OF THESE SHORTWAVES HELP DEVELOP
A SURFACE LOW IN SOUTHEAST COLORADO. GOOD MODEL CONSENSUS EXISTS
THAT THE COLLECTION OF SHORTWAVES WILL DIG DOWN INTO THE CENTRAL
PLAINS WEDNESDAY NIGHT...LEADING TO A SHIELD OF DPVA AND DEFORMATION
FORCED PRECIPITATION DOWNSTREAM. AT THIS TIME IT APPEARS ANY
PRECIPITATION SHOULD HOLD OFF UNTIL THURSDAY. THERE ARE SOME ISSUES
THAT REMAIN FOR THURSDAY...THOUGH. ALTHOUGH GREAT MODEL AGREEMENT
EXISTS BETWEEN THE 16.12Z GFS/NAM/ECMWF/CANADIAN THAT MUCH OF THE
AREA SEES THAT DPVA AND DEFORMATION PRECIPITATION...THE
ECMWF/CANADIAN REMAIN FARTHER NORTH WITH THE ASSOCIATED SURFACE
SYSTEM. IF THESE HOLD TRUE...THUNDER CHANCES WOULD BE REQUIRED FOR
AT LEAST LOCATIONS SOUTH OF I-90. FOR NOW HAVE KEPT THUNDER OUT
GIVEN THAT IT RECENTLY WAS AND THE PERSISTENCE FOR MORE SOUTHERN
SOLUTIONS...BUT THIS WILL NEED TO BE WATCHED. CERTAINLY POTENTIAL
HERE FOR SOME DECENT QPE VALUES TOO...WITH CURRENT FORECAST QPF
ANYWHERE FROM 0.25 TO 0.75 INCHES.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
319 PM CDT MON APR 16 2012
GOOD AGREEMENT REMAINS AMONGST 16.12Z GFS/ECMWF/CANADIAN AND GFS
ENSEMBLES ON SHOWING MAJOR AMPLIFICATION WITH THE UPPER FLOW DURING
THE LONG TERM PERIOD. RIDGING IN THE WESTERN U.S. DEVELOPS THURSDAY
NIGHT THROUGH SATURDAY WHILE A POTENT SHORTWAVE RIDES DOWN THE
RIDGE...FORMING A DEEP TROUGH OVER THE SOUTHEASTERN U.S. BY SATURDAY
NIGHT. BY MONDAY...A BLOCKED UP PATTERN IS FORECAST WITH STRONG
RIDGING OVER THE WESTERN U.S. AND A WIDE/DEEP CUT-OFF UPPER LOW OVER
THE EASTERN U.S.. THIS MEANS A COOL PATTERN FOR THE FORECAST
AREA...THOUGH OVERALL RELATIVELY DRY. REALLY ONLY PRECIPITATION TO
SPEAK OF IS THURSDAY NIGHT...ASSOCIATED WITH DEFORMATION AND DPVA
INDUCED RAIN FROM THURSDAY SLOWLY EXITING. ENOUGH COLD AIR DOES WRAP
DOWN INTO THE AREA FOR A MIX OR CHANGE OVER TO SNOW...THOUGH IT IS
CONCEIVABLE THE PRECIPITATION ENDS BEFORE THE COLDER AIR ARRIVES.
ALSO HAVE A SLIGHT CHANCE OF RAIN SHOWERS IN FOR SATURDAY NIGHT
WHERE THERE ARE SUGGESTIONS OF A SHORTWAVE DROPPING DOWN INTO THE
EASTERN TROUGH. ONLY KEPT AT 20 PERCENT GIVEN VERY FEW MODELS HAVE
THIS PRECIPITATION. IN FACT...LATER FORECASTS MAY BE ABLE TO PULL
THIS IF ALL MODELS TREND TOWARD THE ECMWF/GFS. OTHERWISE...
TEMPERATURES ARE THE STORY WHICH AGAIN LOOK TO HOLD BELOW NORMAL. IN
ADDITION...COULD BE DEALING WITH FREEZE WARNINGS FOR FRIDAY NIGHT
AND POSSIBLY SATURDAY NIGHT AS WELL...IF THE PRECIPITATION DOES NOT
MATERIALIZE. BEST CHANCE FOR FREEZE IS AGAIN ALONG AND NORTH OF
I-94. PERHAPS TOWARDS MONDAY WE WILL BE ABLE TO CLIMB BACK TO NEAR
OR ABOVE NORMAL WITH HINTS OF THE UPPER RIDGE TRYING TO BUILD
TOWARDS THE AREA.
&&
.AVIATION...TONIGHT AND TUESDAY
631 PM CDT MON APR 16 2012
BIGGEST CHALLENGE IS CEILING FORECAST OVERNIGHT TONIGHT. WATER
VAPOR IMAGERY SHOWING A SHORTWAVE ROTATING ALONG THE
IOWA/MINNESOTA BORDER...WITH A SECOND ONE OVER SOUTHEAST NORTH
DAKOTA. SATELLITE SHOWS QUITE A FEW CLOUDS ASSOCIATED WITH BOTH
THESE FEATURES...WITH SOME BREAKS IN SOUTHEAST MINNESOTA. EXPECT
CEILINGS TO RISE IN THE VFR CATEGORY EARLY THIS EVENING AT KRST AND
REMAIN MVFR AT KLSE. THERE COULD BE SOME BREAKS...ESPECIALLY AT
KLSE FOR A FEW HOURS THIS EVENING AND HAVE ADDED A TEMPO SCATTERED
GROUP BETWEEN 01Z-03Z. A LITTLE STRONGER SUBSIDENCE BEHIND THE
LEADING SHORTWAVE AFTER 06Z. CONFIDENCE NOT REAL HIGH FOR CLOUDS
SCATTERING...BUT WILL KEEP THOSE TRENDS IN THIS SET OF TAFS AND
MONITOR THROUGHOUT THE EVENING. EVEN IF CEILINGS REMAIN
BROKEN...IT SHOULD BE IN THE VFR CATEGORY. BETTER CHANCES FOR
SCATTERED CLOUDS ARE AFTER 12Z TUESDAY. WITH THE HIGH MOVING OFF
RATHER QUICKLY...SOUTHERLY WINDS WILL INCREASE TO 10 TO 13 KNOTS
AND ALSO WILL LIKELY BRING A BROKEN DECK BETWEEN 6K-9K FEET LATE
IN THE DAY...ESPECIALLY AT KRST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
319 PM CDT MON APR 16 2012
WI...FREEZE WARNING FROM 1 AM TO 8 AM CDT TUESDAY FOR WIZ017-029-034-
042>044.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1017 AM CDT SUN APR 15 2012
.UPDATE...CONCERNED THAT FOCUS FOR INITIATION OF VIGOROUS/SUPERCELLULAR
CONVECTION WILL BE FURTHER WEST ACROSS ERN IOWA/SRN MINNESOTA
BASED ON OF UPPER JET DYNAMICS AND RUC ORIENTATION OF MLCAPE AXIS.
THESE STRONGER STORMS WOULD THEN SHIFT NORTHEAST...WELL WEST AND
NORTHWEST OF SRN WI. CRAVEN/BROOKS SVR PARAMETER POINTS TOWARDS
THIS REGION AS BEING THE BETTER INITIATION POINT AS DOES 4KM WRF-NMM.
HAVE PULLED BACK ON SEVERE WORDING FOR THE DAY AND LOWERED
POPS...ESPECIALLY IN SE WI. PLENTY OF MID/UPPER CLOUD DEBRIS
LINGERING IN SRN WI. THIN SPOTS WILL EVOLVE WHICH WILL HELP MIX
DOWN STRONGER WINDS AS 850 LOW LEVEL JET RAMPS UP. HOLDING OFF ON
AN ADVISORY AT THIS POINT BUT WILL WATCH CLOUD/MIXING TRENDS
CAREFULLY IN THIS REGARD.
PC
&&
.AVIATION/18Z TAFS/...SPOTTY MVFR CEILINGS LINGERING IN SC WI BUT
EXPECTING THESE LOWER CLOUDS TO MIX OUT WITH TIME. GUSTY SOUTH
WINDS LIKELY TO EVOLVE AS 850 MILLIBAR LOW LEVEL JET RAMPS UP.
CONVECTIVE TRENDS SUGGEST DEVELOPMENT OF MOST VIGOROUS CONVECTION
WILL BE ACROSS IOWA/MINNESOTA AND PERHAPS SHIFT NORTH AND WEST OF
SRN WI. AS SURFACE COLD FRONT DRAWS CLOSER TONIGHT THERE WILL BE A
BETTER CHANCE OF SHOWERS/STORMS THOUGH SOME MODELS SUGGEST A MISS
FOR SRN WI. STAY TUNED.
PC
&&
.MARINE...NO CHANGE TO SMALL CRAFT/GALE HEADLINES...BUT HAVE HOISTED A
DENSE FOG ADVISORY FOR THE NORTHERN ZONE TO ACCOUNT FOR LOWER
VSBYS SEEN ON WEBCAMS. THIS EXPECTED TO IMPROVE THIS AFTERNOON AS
WARM FRONT LIFTS FURTHER NORTH AND WINDS INCREASE.
PC
&&
.PREV DISCUSSION... /ISSUED 555 AM CDT SUN APR 15 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM
MOST OF THE LOW TO MID LEVEL BAROCLINIC ZONE AND WARM ADVECTION WILL
SHIFT NWD THIS MORNING ALONG WITH THE TSTORMS. HOWEVER THE NOSE OF A
BROAD LOW LEVEL JET STREAM WILL REMAIN IN THE VICINITY OF SRN WI SO
SCT SHOWERS/TSTORMS EXPECTED AT TIMES THROUGH THE DAY. DESPITE THIS
SOME BREAKS IN THE CLOUDS ARE EXPECTED LATER TODAY WITHIN THE WARM
SECTOR WITH TEMPS EXPECTED TO CLIMB INTO THE MID 70S.
LOW PRESSURE OVER THE CENTRAL PLAINS WILL DEEPEN TO 986 MB AS IT
MOVES INTO SRN MN BY LATE AFTERNOON AND THEN SLOWLY WEAKEN AS IT
MOVES ACROSS NRN WI. A 60-70 KT LLJ WILL BLAST NWD THROUGH THE WRN
HALF OF WI THIS AFTERNOON AND THEN SHIFT EWD TNT AHEAD OF THE COLD
FRONT. THE POLAR TROUGH/UPPER LOW MOVING INTO MN TNT AND NORTH TO
SOUTH PRE-FRONTAL TROUGH EXTENDING FROM THE LOW WILL TRIGGER MORE
ORGANIZED TSTORMS LATE THIS AFTERNOON AND EVENING. VERY STRONG WIND
SHEAR AND MLCAPES OF 500-1300 J/KG WILL BE IN PLACE FOR SUPERCELLS
OR EMBEDDED SUPERCELLS WITHIN A SEVERE SQUALL LINE. THUS THE SLIGHT
TO MDT RISK FOR ALL TYPES OF SEVERE INCLUDING TORNADOES. IN ADDITION
TO THE STORMS...THE LOW LEVEL JET WILL CREATE WINDY CONDITIONS LATE
THIS AFTERNOON AND FOR MUCH OF THE NIGHT AS LOW LEVEL LAPSE RATES
REMAIN FAIRLY STEEP. WITH 50KTS AT 2 KFT...MOMENTUM TRANSFER OF SVR
WINDS WITH THE TSTORMS WILL BE AN ADDITIONAL FACTOR.
MONDAY AND TUESDAY...FORECAST CONFIDENCE MEDIUM
KEPT CHANCE POPS ON MONDAY WITH TRAILING PRECIP ON THE BACK SIDE OF
THE SFC LOW...ALONG UPPER TROUGH AXIS. TEMPS MAY GENERALLY FALL FROM
MORNING HIGHS...AS COLD ADVECTION...CLOUDS...AND POSSIBLE PRECIP
COOL THINGS OFF. LOOKING EVEN WINDIER WITH LATEST MODEL SOUNDINGS
SUGGESTING GUSTS TO ALMOST 45 MPH POSSIBLE UNDER TIGHT PRESSURE
GRADIENT ON THE BACKSIDE OF THE LOW. MAY HAVE TO EVENTUALLY CONSIDER
A WIND ADVISORY IF MODELS REMAIN THIS WINDY.
COULD SEE SOME FROST MONDAY NIGHT WITH 925 MB FALLING TO AROUND 0C
OR COLDER...ALONG WITH DECREASING CLOUDS AND LIGHTER WINDS. WENT
WITH LOWS IN THE LOW 30S MOST PLACES.
SHOULD BE DRY WITH MOSTLY SUNNY SKIES TUESDAY UNDER SFC HIGH
PRESSURE. NEAR NORMAL HIGH TEMPS EXPECTED EXCEPT FOR NEAR LAKE
MICHIGAN WHERE A LAKE BREEZE SHOULD EASILY DEVELOP AND KEEP THINGS
COOLER.
WEDNESDAY AND THURSDAY...FORECAST CONFIDENCE MEDIUM
MODELS CONTINUE TO COME INTO BETTER AGREEMENT FOR MIDWEEK
SYSTEM...WITH SFC LOW PRESSURE WEDNESDAY AFTERNOON AND THURSDAY
EVENING. SOME TIMING AND PLACEMENT ISSUES STILL EXIST AMONG MODEL
SOLUTIONS...BUT ENOUGH CONFIDENCE FOR HIGH CHANCE TO LIKELY POPS
WEDNESDAY...WITH A CHANCE FOR PRECIP LINGERING INTO THE NIGHT.
MAINLY DRY WEATHER EXPECTED THURSDAY...THOUGH THE ECMWF AND CANADIAN
BRING PRECIP WITH THE NEXT SYSTEM TO OUR DOORSTEP BY EVENING.
SHOULD SEE TEMPS NEAR TO A COUPLE DEGREES ABOVE NORMAL FOR WEDNESDAY
AND THURSDAY.
THURSDAY NIGHT THROUGH SATURDAY...FORECAST CONFIDENCE LOW
NOT MUCH CONFIDENCE WITH FORECAST FROM THURSDAY NIGHT INTO THE
WEEKEND. MODELS CONTINUE TO BOUNCE ALL OVER THE PLACE WITH THURSDAY
NIGHT/FRIDAY SYSTEM. LATEST GFS IS DRY...WHILE THE ECMWF AND
CANADIAN ARE FARTHER NORTH AND BRING PRECIP ACROSS MUCH OR ALL OF
THE FORECAST AREA. STILL POTENTIAL FOR THIS STORM TO BE CHILLY...AS
THE ECMWF SUGGESTING A CHANGEOVER TO SNOW FOR A TIME THU NIGHT. A
CONSENSUS OF MODEL TEMPS NOT COLD ENOUGH FOR SNOW...SO KEPT RAIN
SHOWERS FOR NOW. WILL NEED TO CONTINUE TO KEEP AN EYE ON THIS LATE
WEEK STORM THOUGH...AS IT MAY BE INTERESTING IF ECMWF SOLUTION
PERSISTS.
UNCERTAINTY CONTINUES ON SATURDAY...WITH THE GFS DRY AND THE ECMWF
BRINGING MORE PRECIP BY EVENING.
AVIATION/12Z TAFS/...WIDESPREAD SHOWERS AND TSTORMS EARLY THIS AM
WILL BECOME MORE SCT FOR THE REMAINDER OF THE DAY AS THE WARM SECTOR
MOVES INTO SRN WI. ANOTHER ORGANIZED ROUND OF THUNDERSTORMS...SOME
SEVERE...IS EXPECTED THIS EVENING WITH A PRE-FRONTAL TROUGH LINE. A
SLY 60-70 KT LLJ WILL MAKE FOR WINDY AND GUSTY CONDITIONS LATE THIS
AFTERNOON AND TONIGHT. LIFR TO IFR CIGS AND MVFR VSBYS WILL
TRANSITION TO AREAS OF MVFR CIGS AND VFR VSBYS FOR THIS AFTERNOON
BEFORE WORSENING TNT WITH THE CONVECTION.
MARINE...A SMALL CRAFT ADVISORY GOES IN EFFECT TODAY AND IS
UPGRADED TO A GALE WARNING FOR TONIGHT THROUGH MONDAY AS STRONG LOW
PRESSURE AND LOW LEVEL JET STREAM MOVES ACROSS THE STATE. ADVECTION
FOG THIS MORNING FROM PORT WASHINGTON TO SHEBOYGAN WILL END BY
AFTERNOON AS THE WARM FRONT MOVES THROUGH THE REGION. THE RAIN AT
TIMES WILL BREAK UP THE FOG THIS MORNING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ645-646.
GALE WARNING FROM 7 PM THIS EVENING TO 7 PM CDT MONDAY FOR
LMZ643>646.
SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643-644.
DENSE FOG ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR LMZ643.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...GEHRING
MONDAY THROUGH SATURDAY...DDV
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
400 AM CDT TUE APR 17 2012
...UPDATE TO LONG TERM...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 346 AM CDT TUE APR 17 2012
PATCHY DENSE FOG HAS DEVELOPED OUT ALONG AND WEST OF A LINE FROM SCOTT
CITY AND GARDEN CITY DOWN TOWARD MEADE. MSAS/RUC ANALYSIS IS SHOWING
A SWATH OF LOW DEWPOINT DEPRESSION LINING UP WELL WITH THE FOG. SO FAR
THE FOG HAS REMAINED FAIRLY PATCHY AS INDICATED ON THE 11-3.9 MICRON
SATELLITE CHANNEL. MODEL SOUNDINGS SHOW MOISTURE TO BE VERY SHALLOW
AND THE SURFACE VISIBILITY FORECAST FROM THE HRRR IS TRENDING AWAY
FROM DEVELOPING WIDESPREAD LOW VISIBILITIES THIS MORNING. CURRENT
THINKING IS TO HANDLE THE FOG WITH A MENTION OF PATCHY DENSE IN
THE GRIDS AND NOWCAST IT THROUGH SUNRISE. IF DENSE FOG BECOMES
MORE WIDESPREAD MAY NEED TO ISSUE AN ADVISORY. THE FOG SHOULD BE
FAIRLY QUICK TO BURN OFF TODAY AS LOW LEVEL MIXING ENSUES AND
SOUTH TO SOUTHWEST WINDS INCREASE.
SHORTWAVE RIDGING OVER THE CENTRAL HIGH PLAINS EARLY THIS MORNING WILL
MOVE EAST TODAY WITH ZONAL FLOW SPREADING EASTWARD FROM THE ROCKIES
TODAY AND TONIGHT. GOOD MIXING TODAY WILL RESULT IN TEMPERATURES
CLIMBING INTO THE 70S...WITH UPPER 70S IN THE WEST. THE DEEP MIXING
SHOULD PUSH RELATIVE HUMIDITY LEVELS DOWN INTO THE UPPER TEENS OVER
FAR SOUTHWEST KANSAS. THE LOW RH`S SHOULD BE ATTENUATED SOMEWHAT
BY THE ONGOING GREENUP AND INCREASED EVAPOTRANSPIRATION SO ANY
SIGNIFICANT FIRE WEATHER ISSUES ARE NOT ANTICIPATED.
SOME SCATTERED CIRRUS WILL PASS OVER WESTERN KANSAS TONIGHT AS THE
AFOREMENTIONED SHORTWAVE MOVES EAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 400 AM CDT TUE APR 17 2012
MEDIUM RANGE MODELS INDICATE A ZONAL FLOW ALOFT PERSISTING ACROSS
THE WESTERN HIGH PLAINS TO BEGIN THE PERIOD WEDNESDAY. MEANWHILE, AN
UPPER LEVEL SHORTWAVE TROUGH WILL TRANSITION EAST FROM THE NORTHERN
PLAINS INTO THE GREAT LAKES REGION. A FAIRLY WEAK ATTENDANT COLD
FRONT IS EXPECTED TO PUSH JUST INTO NORTHWESTERN KANSAS BEFORE
STALLING OUT, POSSIBLY JUST INTO NORTHERN PORTIONS OF SOUTHWEST
KANSAS AND PORTIONS OF CENTRAL KANSAS JUST SOUTH OF THE I-70
CORRIDOR. HOWEVER, NO SIGNIFICANT PRECIPITATION IS EXPECTED WITH
THIS FRONT WITH A GENERALLY WEAK FLOW ALOFT. HOWEVER, THE CHANCES
FOR PRECIP DO PICK UP A LITTLE THURSDAY AS ANOTHER UPPER LEVEL
SHORTWAVE IS PROGGED TO SWING ACROSS THE WESTERN PLAINS. AN
ATTENDANT COLD FRONT TO THIS SYSTEM WILL PUSH SOUTHEAST WELL INTO
AND ACROSS WESTERN KANSAS DURING THE DAY THURSDAY BRINGING THE
CHANCE FOR SHOWERS AND A FEW THUNDERSTORMS TO PORTIONS OF WESTERN
KANSAS BY THURSDAY EVENING. HOWEVER, HOW STRONG ANY POSSIBLE STORMS
MAY BE REMAINS UNCERTAIN. NAM AND GFS MODEL SOUNDINGS HINT AT A
POSSIBLE LACK OF LOW LEVEL MOISTURE ALONG WITH LESS THAN FAVORABLE
INSTABILITY LEVELS. ADDITIONALLY, TIMING OF THE FRONT COULD BE AN
ISSUE AS WELL WITH ALL MODELS PROJECTING THE FRONTAL PASSAGE TO TAKE
PLACE EARLIER IN THE DAY. LOW END CHANCE CATEGORY POPS SEEM
REASONABLE AT THIS POINT. DRIER CONDITIONS ARE THEN EXPECTED
THROUGH THE WEEKEND AND INTO THE EARLY PART OF NEXT WEEK AS UPPER
LEVEL RIDGING DEVELOPS AND PUSHES EAST ACROSS THE INTERMOUNTAIN
WEST.
TEMPERATURES ARE EXPECTED TO BE JUST ABOVE NORMAL WEDNESDAY AS A
ZONAL FLOW PERSISTS ACROSS THE WESTERN HIGH PLAINS. A LEE SIDE
TROUGH OF LOW PRESSURE IS EXPECTED TO REDEVELOP ACROSS EASTERN
COLORADO RETURNING A LOW LEVEL SOUTHERLY FLOW TO SOUTHWESTERN AND
SOUTH CENTRAL KANSAS BY LATE AFTERNOON. THE NAM, GFS, AND ECMWF SHOW
H85 TEMPERATURES IN THE MID TO UPPER TEENS(C) ACROSS CENTRAL KANSAS
TO THE LOWER 20S(C) ACROSS SOUTHWESTERN KANSAS. WITH LOWER LEVEL DRY
LAPSE RATES LIKELY BY WEDNESDAY AFTERNOON, LOOK FOR HIGHS UP INTO
THE UPPER 70S(F) TO THE LOWER TO MID 80S(F). A GENERAL COOLING TREND
IS LIKELY THROUGH THE END OF THE WEEK AS MUCH COOLER AIR SURGES
SOUTH INTO WESTERN KANSAS IN WAKE OF THE COLD FRONTAL PASSAGE
THURSDAY. HIGHS COULD STRUGGLE TO REACH THE 70S(F) THURSDAY
DEPENDING ON ANY CLOUD COVER ASSOCIATED WITH THE COLD FRONT
AND THE TIMING OF THE PASSAGE ITSELF.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1237 AM CDT TUE APR 17 2012
VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THROUGH THIS FORECAST
PERIOD. WINDS WILL BECOME GUSTY FROM THE SOUTHWEST FROM LATE TUESDAY
MORNING UNTIL AROUND SUNSET AS DAYTIME MIXING OF THE LOWER ATMOSPHERE
INCREASES. FEW-SCT050 CUMULUS WILL BE POSSIBLE DURING THE AFTERNOON
MAINLY AT DODGE CITY AND HAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 76 49 81 53 / 0 10 0 0
GCK 74 46 81 50 / 0 0 0 0
EHA 76 47 83 51 / 0 0 0 0
LBL 77 48 84 53 / 0 10 0 0
HYS 73 49 78 52 / 0 10 0 0
P28 73 53 81 55 / 0 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GERARD
LONG TERM...JJOHNSON
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
346 AM CDT TUE APR 17 2012
...UPDATED SHORT TERM DISCUSSION...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 346 AM CDT TUE APR 17 2012
PATCHY DENSE FOG HAS DEVELOPED OUT ALONG AND WEST OF A LINE FROM SCOTT
CITY AND GARDEN CITY DOWN TOWARD MEADE. MSAS/RUC ANALYSIS IS SHOWING
A SWATH OF LOW DEWPOINT DEPRESSION LINING UP WELL WITH THE FOG. SO FAR
THE FOG HAS REMAINED FAIRLY PATCHY AS INDICATED ON THE 11-3.9 MICRON
SATELLITE CHANNEL. MODEL SOUNDINGS SHOW MOISTURE TO BE VERY SHALLOW
AND THE SURFACE VISIBILITY FORECAST FROM THE HRRR IS TRENDING AWAY
FROM DEVELOPING WIDESPREAD LOW VISIBILITIES THIS MORNING. CURRENT
THINKING IS TO HANDLE THE FOG WITH A MENTION OF PATCHY DENSE IN
THE GRIDS AND NOWCAST IT THROUGH SUNRISE. IF DENSE FOG BECOMES
MORE WIDESPREAD MAY NEED TO ISSUE AN ADVISORY. THE FOG SHOULD BE
FAIRLY QUICK TO BURN OFF TODAY AS LOW LEVEL MIXING ENSUES AND
SOUTH TO SOUTHWEST WINDS INCREASE.
SHORTWAVE RIDGING OVER THE CENTRAL HIGH PLAINS EARLY THIS MORNING WILL
MOVE EAST TODAY WITH ZONAL FLOW SPREADING EASTWARD FROM THE ROCKIES
TODAY AND TONIGHT. GOOD MIXING TODAY WILL RESULT IN TEMPERATURES
CLIMBING INTO THE 70S...WITH UPPER 70S IN THE WEST. THE DEEP MIXING
SHOULD PUSH RELATIVE HUMIDITY LEVELS DOWN INTO THE UPPER TEENS OVER
FAR SOUTHWEST KANSAS. THE LOW RH`S SHOULD BE ATTENUATED SOMEWHAT
BY THE ONGOING GREENUP AND INCREASED EVAPOTRANSPIRATION SO ANY
SIGNIFICANT FIRE WEATHER ISSUES ARE NOT ANTICIPATED.
SOME SCATTERED CIRRUS WILL PASS OVER WESTERN KANSAS TONIGHT AS THE
AFOREMENTIONED SHORTWAVE MOVES EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 219 PM CDT MON APR 16 2012
WESTERLY DOWNSLOPE FLOW BEGINS TO IMPROVE TOWARDS MID WEEK AS AN
UPPER LEVEL TROUGH EMBEDDED IN THIS FLOW MOVES QUICKLY EASTWARD
TOWARDS THE NORTHERN PLAINS. THIS UPPER LEVEL TROUGH WILL CROSS OUT
INTO THE PLAINS LATE TUESDAY AND AS IT DOES A SURFACE BOUNDARY WILL
MOVE EAST INTO WESTERN KANSAS. JET UPPER LEVEL DYNAMICS APPEAR
LACKING ACROSS WESTERN KANSAS LATE TUESDAY, HOWEVER THERE WILL BE
SOME FORCING DEVELOPING LATE DAY NEAR THIS BOUNDARY THAT WILL BE
LOCATED NEAR WAKEENEY AND DODGE CITY. AT THIS TIME PRECIPITATION
CHANCES TUESDAY NIGHT STILL APPEARS VERY LOW BASED ON THE WEAK
FORCING ALOFT AND WARMING TEMPERATURES IN THE 850-700MB LAYER WHICH
SHOULD SERVE AS A CAP. AS A RESULT WILL CONTINUE TO FAVOR A DRY
FORECAST TUESDAY NIGHT BUT GIVEN THE RETURN OF NEAR 50 DEGREE
SURFACE DEWPOINTS RETURNING ACROSS SOUTH CENTRAL KANSAS WILL
CONTINUE TO FAVOR THE WARMER PREVIOUS FORECAST FOR LOWS WHICH THE
MET NOW APPEARS TO HINTING AT.
THE NEXT IN A SERIES OF UPPER LEVEL DISTURBANCES WILL THEN CROSS OUT
INTO THE PLAINS ON LATE WEDNESDAY AS WARM AIR ADVECTION IMPROVES
NORTH OF A SURFACE BOUNDARY THAT WILL EXTEND FROM WEST TO EAST
ACROSS NORTHERN KANSAS. THIS CONVECTION SHOULD STAY NORTH OF THE I70
CORRIDOR. BASED ON THE NEW 850MB TEMPERATURE TRENDS FROM THE NAM AND
GFS WILL GO AHEAD AN WARM TEMPERATURES UP INTO THE 80 TO 85 DEGREE
RANGE FOR MUCH OF SOUTHWEST KANSAS.
BY LATE WEEK AN UPPER LEVEL RIDGE IS EXPECTED TO DEVELOP ACROSS THE
WESTERN UNITED STATES AS AN UPPER LOW NEAR THE GULF OF ALASKA BEGINS
TO DROP SOUTH/SOUTHEAST. THE NEXT UPPER LEVEL TROUGH WILL MOVE OUT
INTO THE PLAINS ON THURSDAY WHICH WILL ALLOW THE FRONT ACROSS
NORTHERN KANSAS TO CROSS INTO NORTHERN OKLAHOMA BY THURSDAY EVENING.
MOIST UPSLOPE FLOW DEVELOPING NORTH OF THIS FRONT COMBINED WITH THE
LEFT EXIT REGION OF AN UPPER LEVEL JET ROTATING AROUND THIS
DEVELOPING UPPER RIDGE WILL ENHANCE THUNDERSTORM CHANCES ACROSS MUCH
OF WESTERN KANSAS THURSDAY NIGHT. THESE PRECIPITATION CHANCES WILL
END FROM WEST TO EAST EARLY FRIDAY AS THE UPPER RIDGE LOCATED OVER
THE WEST COAST STARTS TO SHIFT EASTWARD TOWARDS THE ROCKIES. AS FOR
TEMPERATURES LATE WEEK AND OVER THE WEEKEND PERIOD...AFTER A COOL
DOWN BEHIND THE FRONT THURSDAY NIGHT AND FRIDAY A WARMING TREND WILL
BEGIN FOR THE WEEKEND PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1237 AM CDT TUE APR 17 2012
VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THROUGH THIS FORECAST
PERIOD. WINDS WILL BECOME GUSTY FROM THE SOUTHWEST FROM LATE TUESDAY
MORNING UNTIL AROUND SUNSET AS DAYTIME MIXING OF THE LOWER ATMOSPHERE
INCREASES. FEW-SCT050 CUMULUS WILL BE POSSIBLE DURING THE AFTERNOON
MAINLY AT DODGE CITY AND HAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 76 49 81 53 / 0 10 0 0
GCK 74 46 81 50 / 0 0 0 0
EHA 76 47 83 51 / 0 0 0 0
LBL 77 48 84 53 / 0 10 0 0
HYS 73 49 78 52 / 0 10 0 0
P28 73 53 81 55 / 0 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GERARD
LONG TERM...BURGERT
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1237 AM CDT TUE APR 17 2012
...UPDATED AVIATION DISCUSSION...
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 212 PM CDT MON APR 16 2012
SYNOPSIS:
THE 16 APRIL 2012 12Z SYNOPTIC MAPS SHOWED A STRONG 125 KT TO 135 KT
300 HPA JET ACROSS MISSOURI. ANOTHER 300 HPA JET STREAK WAS LOCATED
ACROSS QUEBEC. FURTHER UPSTREAM, A 50 KT TO 70 KT 300 HPA JET WAS LOCATED
ACROSS THE PACIFIC NORTHWEST. AT 500 HPA, A MINOR SHORTWAVE TROUGH WAS
MOVING ACROSS THE ROCKIES. MOISTURE ADVECTION DOWNSTREAM OF A 536 DM
LOW WAS OBSERVED ACROSS THE UPPER GREAT LAKES AND INTO THE OHIO RIVER
VALLEY. IN ADDITION, SOME MID LEVEL MOISTURE WAS PUSHING ONSHORE ACROSS
OREGON/WASHINGTON. AT 700 HPA, A RELATIVELY COOL AND DRY AIRMASS HAS
SPREAD OVER THE PLAINS IN THE WAKE OF A DEPARTING SYSTEM. AT 850 HPA,
SOME WRAP AROUND MOISTURE WAS OBSERVED ACROSS MINNESOTA AND STRETCHING
DOWN TO EASTERN KANSAS IN ASSOCIATION WITH A LOW TO MID LEVEL CYCLONE
TO THE NORTHEAST. AT THE SFC, A COLD FRONT WAS ANALYZED FROM SE ONTARIO
TO TEXAS. ANY GULF OF MEXICO MOISTURE WAS SOUTH OF THIS BOUNDARY.
TONIGHT:
VISIBLE SATELLITE AND WSR-88D TRENDS HAVE BEEN ECHOING MODEL OUTPUT,
PARTICULARLY FROM THE HRRR. AS A RESULT, HAVE RELIED HEAVILY ON THIS
MODEL FOR TONIGHT. AN UPPER LEVEL SHORTWAVE TROUGH/400 HPA PV ANOMALY
WILL MOVE ACROSS SOUTHWEST KANSAS THIS EVENING. CONVECTION HAS FORMED
ACROSS SOUTHEAST COLORADO AS A RESULT. EVEN THOUGH DEWPOINTS ARE RUNNING
ONLY IN THE 30S DEG F RANGE, THE HRRR SHOWS SOME WEAK INSTABILITY FORMING.
THIS IS ECHOED IN FORECAST SOUNDINGS ACROSS MY COUNTY WARNING AREA.
100-300 J/KG OF CAPE ALONG WITH FAIRLY STEEP 700 HPA TO 500 HPA WILL
LEAD TO EASTWARD PROPAGATING SHOWERS AND ISOLATED THUNDERSTORMS THROUGH
THE REST OF THIS AFTERNOON AND INTO THE EARLY EVENING. SEVERE WEATHER
IS NOT EXPECTED DUE TO WEAK INSTABILITY/SHEAR. OVERNIGHT LOWS WILL BE SLIGHTLY
WARMER WITH MID 30S DEG F OUT WEST AND MID 40S DEG F ACROSS SOUTH CENTRAL
KANSAS. THE 12Z NAM WAS SHOWING INCREASING 1000-850 HPA MOISTURE, BUT
THINK THIS IS AN OUTLIER COMPARED TO THE REST OF THE MODELS. THE MAIN
IMPLICATIONS FROM THIS WOULD BE AREAS OF STRATUS AND SLIGHTLY WARMER
MINIMUMS UNDER THE CLOUD DECK. WILL HOLD OFF FOR NOW ON THIS SOLUTION.
TOMORROW:
FLAT 500 HPA RIDGING IS EXPECTED ACROSS THE ROCKIES AND HIGH PLAINS
TOMORROW. THIS WILL LEAD TO WESTERLY FLOW ALOFT AND DOWNSLOPE SOUTHWESTERLY
SURFACE TO 600 HPA WINDS. THE ATMOSPHERE BECOMES DEEPLY MIXED TO ABOUT
650 HPA WHICH SUPPORTS WARMER MAXIMUM TEMPERATURES FOR TOMORROW VIA
ADIABATIC COMPRESSIONAL WARMING. THE WIND PROFILE WITHIN THIS LAYER
IS NOT PARTICULARLY STRONG, BUT I DO THINK BREEZY CONDITIONS ARE EXPECTED
AS MIXING AND RESULTANT MOMENTUM TRANSFER DEVELOPS/CONTINUES TOMORROW.
HIGHS WILL BE IN THE 70S DEG F RANGE. NO PRECIPITATION IS EXPECTED AS
SUBSIDENCE IN THE WAKE OF THE TROUGH PREVAILS. A LEE SURFACE TROUGH
ACROSS EASTERN COLORADO WILL CONTINUE AS WELL WITH THE AFOREMENTIONED
PERPENDICULAR FLOW TO THE ROCKIES.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 219 PM CDT MON APR 16 2012
WESTERLY DOWNSLOPE FLOW BEGINS TO IMPROVE TOWARDS MID WEEK AS AN
UPPER LEVEL TROUGH EMBEDDED IN THIS FLOW MOVES QUICKLY EASTWARD
TOWARDS THE NORTHERN PLAINS. THIS UPPER LEVEL TROUGH WILL CROSS OUT
INTO THE PLAINS LATE TUESDAY AND AS IT DOES A SURFACE BOUNDARY WILL
MOVE EAST INTO WESTERN KANSAS. JET UPPER LEVEL DYNAMICS APPEAR
LACKING ACROSS WESTERN KANSAS LATE TUESDAY, HOWEVER THERE WILL BE
SOME FORCING DEVELOPING LATE DAY NEAR THIS BOUNDARY THAT WILL BE
LOCATED NEAR WAKEENEY AND DODGE CITY. AT THIS TIME PRECIPITATION
CHANCES TUESDAY NIGHT STILL APPEARS VERY LOW BASED ON THE WEAK
FORCING ALOFT AND WARMING TEMPERATURES IN THE 850-700MB LAYER WHICH
SHOULD SERVE AS A CAP. AS A RESULT WILL CONTINUE TO FAVOR A DRY
FORECAST TUESDAY NIGHT BUT GIVEN THE RETURN OF NEAR 50 DEGREE
SURFACE DEWPOINTS RETURNING ACROSS SOUTH CENTRAL KANSAS WILL
CONTINUE TO FAVOR THE WARMER PREVIOUS FORECAST FOR LOWS WHICH THE
MET NOW APPEARS TO HINTING AT.
THE NEXT IN A SERIES OF UPPER LEVEL DISTURBANCES WILL THEN CROSS OUT
INTO THE PLAINS ON LATE WEDNESDAY AS WARM AIR ADVECTION IMPROVES
NORTH OF A SURFACE BOUNDARY THAT WILL EXTEND FROM WEST TO EAST
ACROSS NORTHERN KANSAS. THIS CONVECTION SHOULD STAY NORTH OF THE I70
CORRIDOR. BASED ON THE NEW 850MB TEMPERATURE TRENDS FROM THE NAM AND
GFS WILL GO AHEAD AN WARM TEMPERATURES UP INTO THE 80 TO 85 DEGREE
RANGE FOR MUCH OF SOUTHWEST KANSAS.
BY LATE WEEK AN UPPER LEVEL RIDGE IS EXPECTED TO DEVELOP ACROSS THE
WESTERN UNITED STATES AS AN UPPER LOW NEAR THE GULF OF ALASKA BEGINS
TO DROP SOUTH/SOUTHEAST. THE NEXT UPPER LEVEL TROUGH WILL MOVE OUT
INTO THE PLAINS ON THURSDAY WHICH WILL ALLOW THE FRONT ACROSS
NORTHERN KANSAS TO CROSS INTO NORTHERN OKLAHOMA BY THURSDAY EVENING.
MOIST UPSLOPE FLOW DEVELOPING NORTH OF THIS FRONT COMBINED WITH THE
LEFT EXIT REGION OF AN UPPER LEVEL JET ROTATING AROUND THIS
DEVELOPING UPPER RIDGE WILL ENHANCE THUNDERSTORM CHANCES ACROSS MUCH
OF WESTERN KANSAS THURSDAY NIGHT. THESE PRECIPITATION CHANCES WILL
END FROM WEST TO EAST EARLY FRIDAY AS THE UPPER RIDGE LOCATED OVER
THE WEST COAST STARTS TO SHIFT EASTWARD TOWARDS THE ROCKIES. AS FOR
TEMPERATURES LATE WEEK AND OVER THE WEEKEND PERIOD...AFTER A COOL
DOWN BEHIND THE FRONT THURSDAY NIGHT AND FRIDAY A WARMING TREND WILL
BEGIN FOR THE WEEKEND PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1237 AM CDT TUE APR 17 2012
VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THROUGH THIS FORECAST
PERIOD. WINDS WILL BECOME GUSTY FROM THE SOUTHWEST FROM LATE TUESDAY
MORNING UNTIL AROUND SUNSET AS DAYTIME MIXING OF THE LOWER ATMOSPHERE
INCREASES. FEW-SCT050 CUMULUS WILL BE POSSIBLE DURING THE AFTERNOON
MAINLY AT DODGE CITY AND HAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 48 80 53 75 / 10 0 0 20
GCK 45 80 50 73 / 0 0 0 20
EHA 46 82 51 75 / 0 0 0 30
LBL 47 83 53 76 / 10 0 0 20
HYS 48 77 52 71 / 10 0 10 10
P28 52 80 55 77 / 10 0 0 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...BURGERT
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS JACKSON KY
213 AM EDT TUE APR 17 2012
.UPDATE...
ISSUED AT 213 AM EDT TUE APR 17 2012
OTHER THAN THE ADJUSTMENTS TO THE HOURLY TEMP CURVES MAINLY TO
ACCOUNT FOR COLDER VALLEY TEMPS IN SOME PLACES...VERY LITTLE CHANGE
WAS NEEDED AT THIS POINT FOR THE OVERNIGHT PERIOD. THE LATEST WRF RUN
AND 21Z SREF AS WELL AS SOME OF THE HRR RUNS SUPPORT AN ISOLATED
SHOWER OR PERHAPS PATCHY LIGHT RAIN NEAR THE KY/VA/TN TRI STATE AREA
LATER ON TONIGHT INTO EARLY ON TUE.
UPDATE ISSUED AT 906 PM EDT MON APR 16 2012
SHOWERS AND TSTORMS THAT DEVELOPED ALONG THE FRONT ARE NOW EXITING
OUR VA BORDER COUNTIES. THE PAST COUPLE RUNS OF THE HRRR BRING
ANOTHER AREA OF SHOWERS NORTHEAST FROM NORTHERN ALABAMA INTO FAR
SOUTHEAST KENTUCKY TOWARDS DAWN SO WILL LINGER A 20 POP OVERNIGHT
INTO EARLY TUESDAY MORNING FOR BELL AND HARLAN COUNTIES. THE REST OF
THE AREA SHOULD REMAIN DRY. THE REMAINDER OF THE FORECAST LOOKS ON
TRACK WITH JUST SOME FINE TUNING OF SKY/TEMPS/DEWS NEEDED. HAVE A
GOOD NIGHT.
UPDATE ISSUED AT 523 PM EDT MON APR 16 2012
ILL DEFINED COLD FRONT IS WORKING ACROSS THE AREA WITH ANOTHER TROUGH
EVIDENT BY A WIND SHIFT ENTERING NORTH CENTRAL KENTUCKY AT THIS TIME.
RADAR RETURNS NEAR LAKE CUMBERLAND ARE LIKELY VIRGA AND ANY
ADDITIONAL SHOWER ACTIVITY THIS EVENING SHOULD BE ISOLATED AT BEST
AND HAVE TRIMMED BACK NEAR TERM POPS TO FIT THAT SCENARIO.
OTHERWISE...HAVE JUST PROVIDED SOME TWEAKS TO TEMPS/DEWPOINTS/SKY
COVER/WINDS TO FIT CURRENT AND EXPECTED NEAR TERM CONDITIONS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 215 PM EDT MON APR 16 2012
WAVE OF SHRA CROSSING ERN KY THIS AFTERNOON. PROJECTING THE TRAILING
EDGE OF THE PCPN HAS IT JUST EAST OF THE STATE BY 8 PM. THIS IS WELL
REFLECTED IN NEARLY ALL THE MODELS. CLOUD COVER EXTENDS FROM MI TO TX
SO CLEARING WILL TAKE A WHILE TONIGHT AND WILL KEEP CONSIDERABLE
CLOUDS IN FCST THRU THE OVERNIGHT PERIOD TONIGHT. COOLER AIR WILL
THEN CYCLE BACK INTO THE AREA FOR TUE AS TEMPS BEHIND THE FRONT ARE
10-15 DEG COOLER THAN PRE FRONTAL. EXPECTING HIGHS ON TUE ONLY TO
REACH THE MID 60S. THE CURRENT FRONT WILL STALL TO OUR SOUTH
THRU TUE AND THEN A WAVE IN THE GULF WILL SLIDE EAST AND WAVE THE
BOUNDARY BACK TO THE NORTH LATE TUE NIGHT WITH CHANCE POPS IN OUR
SERN COUNTIES. THE CHANCE OF RAIN DROPS OFF QUICKLY AS YOU HEAD NORTH
AND THE BLUEGRASS COUNTIES IN OUR NORTHERN FCST AREA SHOULD BE RAIN
FREE. THE CLOUD COVER THAT ACCOMPANIES THE RAIN TUE NIGHT WILL KEEP
OVERNIGHT LOWS A BIT WARMER IN THE SOUTH. THE PARTLY CLOUDY SKIES AND
LIGHT WINDS TUE NIGHT WILL ALLOW TEMPS TO DROP INTO THE UPPER 40S
SOUTH AND MID 40S NORTH...WHICH IS ABOUT NORMAL FOR THIS TIME OF THE
YEAR.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 300 PM EDT MON APR 16 2012
THE EXTENDED FORECAST PERIOD BEGINS ON WEDNESDAY WITH A PROGRESSIVE
MOSTLY ZONAL PATTERN IN PLACE. A DEVELOPING SHORTWAVE LOCATED OVER
THE SOUTHEAST EXITS THE EAST COAST BY WEDNESDAY NIGHT. AT THE
SURFACE...DURING THE DAY WEDNESDAY...A LOW DEVELOPS AND MOVES NE OFF
THE EAST COAST. EASTERN KENTUCKY WILL STILL STAND TO RECEIVE SOME
DEFORMATION PRECIP ON THE BACK EDGE OF THE SYSTEM AS IT EXITS OFF TO
THE NORTHEAST. WEAK RIDGING THEN WILL KEEP EASTERN KENTUCKY DRY FOR
THE THURSDAY THROUGH FRIDAY NIGHT TIME FRAME. BY FRIDAY NIGHT...THE
UPPER LEVEL PATTERN GAINS SOME AMPLITUDE AND BECOMES MERIDIONAL AS BY
SATURDAY...A TROUGH DIGS INTO THE SOUTH CENTRAL PLAINS WHILE RIDGING
BUILDS IN THE SOUTHWEST AND OFF THE EAST COAST. BY LATE
SATURDAY...SURFACE LOW PRESSURE REDEVELOPS ALONG A NEARLY STALLED
BOUNDARY DRAPED FROM THE LOWER MS VALLEY NORTHEAST INTO THE OH
VALLEY. THE SYSTEM STRENGTHENS AS IT BEGINS TO MOVE UP THE EAST
COAST. BOTH THE EURO AND GFS PAINT THIS SIMILAR SCENARIO.
AFTER RUNNING THE INITIALIZATION...HAD TO TRIM BACK POPS FOR THE
APPROACHING FRONT FRIDAY NIGHT. THE DEVELOPING AMPLITUDE OF THE
PATTERN WOULD SUGGEST A SLOWING TO THE APPROACH OF THE FRONT AND THE
12Z GFS AND 00Z EURO AGREE TO THIS SO BROUGHT THE BULK OF THE POPS
INTO THE AREA BY 12Z SATURDAY. WITH BOTH THE GFS AND THE EURO CLOSING
OFF THE UPPER LOW OVER THE EAST TOWARD THE END OF THE PERIOD AND THE
SURFACE LOW TRANSITIONING TO A COASTAL LOW TYPE SET UP...KEPT POPS IN
THE FORECAST FOR THE REST OF THE EXTENDED. OTHERWISE...ANY OTHER
ADJUSTMENTS WERE FOR TERRAIN AND MATCHING UP WITH NEIGHBORING
OFFICES.
WITH THE SOUTHERLY FLOW AHEAD OF THE LOW FOR THE FIRST FEW DAY OF
THE EXTENDED...HIGHS WILL BE AROUND IF NOT A LITTLE ABOVE NORMAL. BY
DAYS 6 AND 7...TEMPERATURES WILL DROP BY 5 TO 10 DEGREES BELOW NORMAL
AS AT THIS POINT...MODELS ARE INDICATING QUITE A BIT OF COLDER AIR
BEHIND THIS SYSTEM.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 213 AM EDT TUE APR 17 2012
A COLD FRONT WILL STALL OUT TO OUR SOUTHEAST OVER THE NEXT 6 TO 12
HRS. A WAVE OF LOW PRESSURE WILL FORM AND MOVE ALONG THIS FRONT ON
TUESDAY INTO TUE NIGHT KEEPING CLOUDS RATHER PROLIFIC DURING THE
PERIOD...ALTHOUGH CIGS WILL BE VFR. OTHER THAN SOME ISOLATED SHOWERS
OR PATCHY LIGHT RAIN BETWEEN 9Z AND 15Z NEAR 1A6...LIGHT RAIN IS NOT
EXPECTED TO ACROSS EAST KY UNTIL AFTER 22Z NEAR THE TN AND VA BORDERS.
THIS THREAT FOR SOME LIGHT RAIN WILL THEN SPREAD NW THROUGH THE END
OF THE PERIOD...BUT CIGS WITH THIS SHOULD STILL REMAIN VFR. GENERALLY
LIGHT NORTH TO NORTHEASTERLY WINDS ARE EXPECTED THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...DUSTY
LONG TERM....SHALLENBERGER
AVIATION...JP
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
447 AM EDT TUE APR 17 2012
.SYNOPSIS...
ISSUED AT 443 AM EDT TUE APR 17 2012
00Z RAOBS/LATEST WV IMAGERY AND LATEST RUC ANALYSIS SHOW SHRTWV
RESPONSIBLE FOR WINTRY MIX/GUSTY WINDS YDAY SHEARING ENEWD OVER
ONTARIO ON NW FLANK OF SHARP UPR RDG OFF THE SE COAST. ALTHOUGH
ASSOCIATED SFC LO IS WEAKENING AND MOVING QUICKLY TO THE E THRU
QUEBEC...SOME SHSN ARE FALLING OVER THE NCNTRL AND E AS OF MIDNGT
UNDER THE WEAKENING BUT LINGERING CYC NW FLOW LEFT IN ITS WAKE.
00Z H85 TEMPS AS LO AS -11C PER RUC ANALYSIS AND CONSIDERABLE
LLVL MSTR/INVRN BASE ARND H85 SHOWN ON THE 00Z APX RAOB ARE
CONDITIONS CONDUCIVE FOR THIS BIT OF LATE SEASON LES AND EXTENSIVE
LK SC. UNDER THE H85 THERMAL TROF...SFC TEMPS ARE QUITE CHILLY WITH
TEMPS GENERALLY IN THE 20S. ALTHOUGH PTCHY LO CLDS ARE STILL PRESENT
AS FAR W AS THE MN ARROWHEAD...ANY LINGERING PCPN IS ENDING OVER THE
W WITH APRCH OF TRAILING HI PRES RDG AND VERY DRY AIR SHOWN ON THE
00Z INL RAOB /PWAT 0.13 INCH/. LOOKING FARTHER W...AN UPPER RDG IS
BLDG INTO THE PLAINS WITH 12Z-24Z H3 RISES ARND 150M OVER THE NRN
PLAINS AND S OF NRN BRANCH TROF OVER CENTRAL CANADA. 00Z BISMARCK
RAOB DOES SHOW SOME MSTR THAT SUPPORTED A GOOD AMOUNT OF SC IN THE
NRN PLAINS YDAY. ANOTHER SHRTWV IS MOVING ONSHORE IN THE PAC NW.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 443 AM EDT TUE APR 17 2012
MAIN FCST CONCERNS DURING THIS TIME ARE PCPN TRENDS EARLY THIS
MRNG...TEMPS TODAY...AND THEN PCPN CHCS LATE TNGT THRU WED
ASSOCIATED WITH SHRTWV NOW MOVING THRU THE PAC NW.
EARLY THIS MRNG...AS SHRTWV/SFC LO TO THE E CONTINUE TO SLIDE AWAY
AND HI PRES BUILDS INTO THE WRN CWA BY 09Z UNDER STEADY H5
RISES/DNVA THAT IS FCST TO LOWER INVRN BASE TO UNDER 3K FT AT ERY BY
09Z. SO ALTHOUGH QUITE A BIT OF SC WILL LINGER...EXPECT ANY -SHSN TO
BE OVER BY 12Z. LINGERING SC OVER MUCH OF THE CWA WL LIMIT
ADDITIONAL DIURNAL TEMP DROP.
TODAY...WITH HI PRES/DRY AIRMASS PUSHING E ACROSS THE CWA...EXPECT
LAKE EFFECT SC IN THE MRNG TO DISSIPATE IN THE PRESENCE OF DAYTIME
HEATING AND WEAKENING CYC FLOW. BUT WITH HINT OF LINGERING H85
THERMAL TROF AND ARRIVAL OF SOME MSTR SHOWN ON THE 00Z BISMARCK
RAOB...MORE DIURNAL CU/SC SHOULD DVLP OVER MAINLY THE W HALF
INTERIOR INLAND AWAY FM LK BREEZES THAT FORM IN THE RELATIVELY WEAK
PRES GRADIENT. MIXING TO H85-8 ON NAM FCST SDNGS YIELD HI TEMPS
RANGING FM ARND 40 AT ERY TO THE UPR 40S NEAR THE WI BORDER. WITH LK
BREEZE FORMATION...EXPECT COOLER READINGS NEAR THE LK SHORES.
TNGT...LATEST NUMERICAL MODELS IN GOOD AGREEMENT SHOWING SHRTWV NOW
IN THE PAC NW/ACCOMPANYING SFC LO MOVING THRU THE NRN PLAINS AND
INTO NE MN BY 12Z WED...WITH WAD PCPN IN ADVANCE OF THIS FEATURE
OVERSPREADING THE W HALF OF UPR MI BY SUNRISE. MAIN FORCING
MECHANISMS LOOK TO BE VIGOROUS UPR DVGC IN LEFT EXIT OF SUPPORTING
H3 JET MAX/VIGOROUS ISENTROPIC ASCENT POWERED BY H85 SW 50-60KT
WINDS/VIGOROUS H85-7 FGEN IN ADVANCE OF ATTENDANT WARM FNT. OPTED TO
BUMP POPS UP TO CATEGORICAL OVER THE W AFT 06Z GIVEN THESE POTENT
DYNAMICS/IMPRESSIVE DEEP LYR QVECTOR CNVGC/MODEL CONSISTENCY ON
GENERATING PCPN IN THIS AREA. ALTHOUGH FCST H100-85 THKNS AS HI AS
1320-1335M IN ADVANCE OF PCPN ARRIVAL...RAPID ARRIVAL OF WAD
CLD...FASTER ADVECTION OF HIER LLVL SPECIFIC HUMIDITY THAN EARLIER
FCSTS INDICATED...ONSET OF STRONGER WINDS INDICATE PCPN SHOULD BE
ALL RA...INITIAL RELATIVE DRYNESS OF LLVLS THAT LOWERS WBLB TO BLO
32 AT THE SFC SUPPORTS MAINTAING A MENTION OF A BIT OF -FZRA AT THE
ONSET OF THE RA SHIELD OVER THE INTERIOR. ANY ICING WOULD BE
INSIGNIFICANT DUE TO STEADY WARMING SOON AFT PCPN ARRIVAL. UTILIZED
A NON-DIURNAL TEMP CURVE TO HANDLE TEMP TRENDS. TEMPS WL BE LOWEST
AND SINK BLO 32 OVER THE E...BUT PCPN WL NOT GET THERE BEFORE
SUNRISE. ALTHOUGH GFS/NAM SHOW LAPSE RATES NOT MUCH STEEPER THAN
MOIST ADIABATIC/ MUCAPE UNDER 50 J/KG...RETAINED MENTION OF SCHC TS
GIVEN VIGOROUS DYNAMICS/STRONG WARMING AT H85.
WED...SINCE THE SHRTWV/SFC LO AND ACCOMPANYING DYNAMICS ARE FCST TO
MOVE STEADILY EWD...EXPECT THE HIER POPS TO SHIFT W-E THRU THE CWA.
THERE IS AN INDICATION THAT WITH AFTN DRYING/RETURN OF SOME
SUNSHINE...THERE WL BE ENUF DESTABILIZATION TO RESULT IN SOME
SHRA/TS OVER THE INTERIOR W HALF. BUT FCST LARGER SCALE QVECTOR DVGC
IN THE WAKE OF THE DISTURBANCE THAT SHARPENS THE MID LVL INVRN
SHOULD LIMIT THIS CHC. WL RETAIN NO HIER THAN SCHC-CHC POPS OVER THE
INTERIOR FOLLOWING THE DEPARTURE OF THE DEEPER MSTR GIVEN FCST KINX
BLO 20 ON NAM FCST SDNGS.
WED NGT...HI PRES BLDG INTO AREA UNDER DNVA IN THE WAKE OF THE
DEPARTING SHRTWV WL BRING DRY WX TO THE CWA. ALTHOUGH THERE COULD BE
SOME LK CLDS IN THE ABSENCE OF DAYTIME HEATING WITH H85 TEMPS
SINKING AS LO AS -6C...DRYNESS OF THE INCOMING AIRMASS AND LLVL ACYC
FLOW SUGS THIS POTENTIAL IS LO.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 443 AM EDT TUE APR 17 2012
AFTER PASSAGE OF SHORTWAVE TROUGH...UPPER AIR PATTERN FOR THURSDAY
FEATURES INCREASING CONFLUENT FLOW EARLY ON. PRIMARY RESULT IS SFC
RIDGE OVR CNTRL CANADA BUILDING INTO UPPER LAKES REGION THROUGH THE
DAY AS SFC FRONTAL BOUNDARY SETTLES INTO CNTRL GREAT LAKES TO
NORTHERN FRINGE OF OHIO VALLEY. BY THURSDAY AFTN...H85 BAROCLINIC
ZONE FCST TO BE MORE FM NORTHERN IOWA INTO CNTRL LOWER MICHIGAN.
NEXT SHORTWAVE TROUGH ALREADY EMERGING ONTO THE PLAINS BY DAYBREAK
THURSDAY WILL BE QUICKLY HEADING INTO WESTERN GREAT LAKES BY AFTN.
MODELS REMAIN AT ODDS ON HOW FAR NORTH TO BRING SFC-H85 LOW PRESSURE
BY LATE THURSDAY AFTN. OPERATIONAL GFS AND GFS ENSEMBLES KEEP THE
LOW TIED TO SFC FRONT THAT WILL BE OVER SOUTHERN PORTIONS OF GREAT
LAKES AND INTO NORTHERN OHIO VALLEY. GFS HAS SHOWED A MORE SOUTHERN
SUPPRESSED SOLUTION FOR THIS SYSTEM QUITE SOME TIME NOW. OTHER
EXTREME IS ECMWF AND ASSOCIATED ENSEMBLES WHICH RIDE SFC LOW
MORE ALONG H85 THERMAL GRADIENT OVR WI AND LOWER MI. THUS...ECMWF
INSISTS THAT MAJORITY OF CWA EXCEPT FOR PERHAPS FAR NW WOULD BE
IMPACTED BY PRECIPITATION. NAM/UKMET AND THE CANADIAN REPRESENT
MIDDLE GROUND CLIPPING SOUTHERN AND EASTERN CWA WITH PRECIPITATION
BUT OTHERWISE KEEPING CWA DRY.
IT IS BECOMING APPARENT THAT A BIG KEY FOR THIS SYSTEM IS EXTENT OF
DRY AIR THAT LURKS AHEAD OF THE SYSTEM AS LATE AS THURSDAY AFTN.
FCST SOUNDINGS FM GFS/ECMWF AND NAM SHOW POCKET OF DRY AIR LINGERING
BTWN H9 AND H7. NAM IS QUITE EMPHATIC WITH THE DRY AIR SHOWING H85
AT 18Z THURSDAY AOB -20C OVR MUCH OF THE CWA BEFORE ERODING THIS
SOMEWHAT BY 00Z FRIDAY. DRY AIR FLOWING IN ON NORTHEAST SFC WINDS FM
LARGE HIGH PRESSURE OVR NORTHERN ONTARIO AND FACT THAT RIBBON OF
SHARP FRONTOGENEIS IS FCST OVR UPR LAKES SUPPORTS IDEA THAT THERE
COULD BE VERY SHARP CUTOFF TO NORTHERN EXTENT OF PRECIPITATION.
INTERESTING THAT EVEN THE ECMWF SHOWS H85 FGEN AXIS JUST SOUTH OF
CWA WITH H7 FGEN AXIS ROUGHLY FM IMT TO SSM ON THURSDAY NIGHT.
IMAGINE MOST OF THE PRECIPITATION FM THE SYSTEM WILL OCCUR ON THE
SOUTHERN EDGE OF THE H7 FGEN...SO THAT WOULD LEAVE FAR SOUTHEAST CWA
IN LINE TO SEE MOST PRECIPITATION WITH THE SYSTEM. MAJORITY OF THE
PRECIP WOULD PROBABLY FALL THURSDAY NIGHT AS THE LEADOFF FORCING ON
THURSDAY WILL ONLY SERVE TO MOISTEN THE VERY DRY LOW-LEVELS. PREV
FCST MATCHES UP WITH THIS THINKING WELL KEEPING HIGHEST POPS NEAR LK
MICHIGAN ON THURSDAY NIGHT. THIS ALSO MATCHES SURROUNDING WFOS VERY
NICELY.
NOW ON TO PTYPE. LOOKS LIKE SNOW FOR MUCH OF THE EVENT. NORTHEAST
SFC WINDS PROBABLY MITIGATE WARMING EFFECT OFF LK MICHIGAN FOR ALL
BUT SOUTHERN MNM COUNTY. ALSO LARGER SCALE FORCING/INTENSE
PRECIPITATION RATES MOST LIKELY WILL OVERWHELM A MINIMAL NEAR SFC
WARM LAYER. 1000-850MB THICKNESSES AND H85 TEMPS FM ECMWF SUPPORT
MAINLY SNOW BY LATER EVENING INTO THE OVERNIGHT HOURS. WWD GRAPHICS
FM HPC INDICATE SEVERAL INCHES OF SNOW POSSIBLE OVR SOUTH AND EAST
CWA ONCE THE RAIN CHANGES TO SNOW. EVEN THOUGH THIS COULD OCCUR IN
NON-GFS SOLUTIONS...REALLY TOUGH TO GO WITH MORE THAN CHANCY POPS
WITH DOWNPLAYED QPF/SNOW AT THIS POINT GIVEN PERSISTENT GFS SOUTHERN
SOLUTION AND FACT THAT SHARP CUTOFF COULD ULTIMATELY PUSH MOST OF
THE PRECIPITATION TO THE SOUTH OF CWA. SYSTEM IS CURRENTLY CHURNING
ACROSS EASTERN PACIFIC HEADING FOR WEST COAST. LOOKS PRETTY SHARP
AND WRAPPED UP ALREADY. UNTIL THE SYSTEM GETS BETTER SAMPLED BY ROAB
NETWORK OVR THE CONUS...PROBABLY WILL BE SEEING MODEL SOLUTIONS
SHOWING VARIABILITY WITH TRACK OF THE SYSTEM. IN OTHER WORDS...STAY
TUNED.
VERY QUIET BEYOND EARLY FRIDAY MORNING. BY FRIDAY AFTN...DEEP H85-H7
DRYING EVEN SHOWN BY STRONGER ECMWF...SO SKIES SHOULD BECOME MOSTLY
SUNNY ALL AREAS. HIGH PRESSURE RIDGE FM HUDSON BAY INTO QUEBEC WILL
BE DOMINANT SFC FEATURE THIS WEEKEND. EXPECT MOSTLY CLEAR SKIES WITH
TEMPERATURES STAYING BLO NORMAL NEAR THE LAKES AND POSSIBLY NEAR
NORMAL INLAND TOWARD WI BORDER /NORMAL HIGHS AT WFO MARQUETTE IN UPR
40S/. NIGHTTIME LOWS WILL LIKELY BE BELOW NORMAL WITH SOME NIGHTS IN
THE TEENS POSSIBLE WITH THE HIGH AND DRY AIRMASS OVERHEAD. EXPECT
AFTN HUMIDITY VALUES TO DROP INTO THE 30-35 PCT RANGE THOUGH COULD
EVEN SEE LOWER READINGS WITH DEEPER MIXING. LIGHT WINDS...COOLER
TEMPS...AND RECENT RAINFALL IN SOME AREAS SHOULD KEEP FIRE WX ISSUES
IN CHECK THROUGH THE WEEKEND THOUGH. APPEARS THAT WARMER TEMPS AND
POSSIBLY WINDY CONDITIONS ARE POSSIBLE EARLY TO MID NEXT WEEK...
THOUGH LATEST ECMWF/GFS INDICATE THIS WARM UP WITH BE REPLACED BY
ANOTHER COOL DOWN JUST BEYOND DAY 7.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 124 AM EDT TUE APR 17 2012
LIGHT SNOW SHOWERS WILL BE ENDING OVERNIGHT AT KCMX AND KSAW AS RDG
BUILDS IN FM WEST. MVFR CLOUD DECK SHOULD SCT OUT AT KIWD AROUND 09Z
AS WINDS SHIFT TO THE SE. WITH WEAKENING NW FLOW AT KCMX AND KSAW IT
WILL TAKE A BIT LONGER FOR CLRG TO REACH THERE (AROUND 12Z). 850 MB
COLD POOL AT LEAST INITIALLY MAY KEEP SOME SCT CUMULUS AROUND
THROUGH AT LEAST THE MORNING HRS ON TUE. ERLY LAKE BREEZE SHOULD
KICK IN AT KCMX BY MIDDAY. EXPECT INCREASING MID-HIGH CLOUDS TUE
EVENING AHEAD OF APPROACHING SYSTEM OVER THE PLAINS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 AM EDT TUE APR 17 2012
EXPECT LIGHT WINDS INTO TONIGHT WITH HI PRES RIDGE BUILDING INTO THE
AREA. AS A LO PRES SYSTEM APPROACHES TONIGHT AND THE PRES GRADIENT
SHARPENS OVER THE LAKE...S WINDS WILL INCREASE TO AROUND 30 KTS OVER
THE E HALF WED MORNING. IN THE WAKE OF THIS LO PUSHING TO THE E LATE
WED/WED NIGHT...PLAN ON A WSHFT TO THE W WITH WINDS UP TO 25-30 KTS.
THESE STRONGER WINDS WILL DIMINISH AGAIN ON WED NIGHT AS ANOTHER HI
PRES RIDGE BUILDS TOWARD THE UPPER LAKES. DEPENDING ON HOW FAR NORTH
A LOW PRESSURE SYSTEM MOVES...NE WINDS COULD INCREASE TO 25 KTS OVER
SOUTHEAST LAKE SUPERIOR. HI PRES BUILDING INTO THE GREAT LAKES WILL
BRING LIGHTER WINDS FOR THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLA
AVIATION...VOSS
MARINE...KC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
144 AM EDT TUE APR 17 2012
.SYNOPSIS...
ISSUED AT 408 PM EDT MON APR 16 2012
WINDY CONDITIONS WILL CONTINUE INTO THE EVENING HOURS BEFORE
SUBSIDING AFTER DARK. HIGH WINDS CAN BE EXPECTED THROUGH 800 PM OR
SO. SCATTERED RAIN SHOWERS THIS EVENING WILL MIX WITH SOME SNOW
BEFORE ENDING TOWARDS MIDNIGHT. OVERNIGHT CLOUDS WILL DECREASE AS
WILL THE WINDS SETTING THE STAGE FOR ANOTHER ROUND OF FROST AND
FREEZING TEMPERATURES LATE. A DRY AND COOL DAY IS EXPECTED ON
TUESDAY...BEFORE RAIN RETURNS TO THE FORECAST FOR
WEDNESDAY...THURSDAY AND FRIDAY. THE RAIN WILL BE ASSOCIATED WITH
A FRONTAL BOUNDARY THAT LINGERS IN THE REGION.
&&
.UPDATE...
ISSUED AT 906 PM EDT MON APR 16 2012
WE WENT AHEAD AND CANCELLED THE WIND ADVISORY EARLY AS WINDS HAVE
DIMINISHED WELL BELOW ADVISORY CRITERIA AS THE GRADIENT WEAKENS
AND DIURNAL MIXING IS LOST. THE FROST ADVISORY/FREEZE WARNING
REMAINS AS IS WITH NO CHANGES NEEDED THERE.
WE ALSO PULLED MOST OF THE PCPN FOR THE EVENING HOURS. REGIONAL
RADAR IMAGERY AND SFC OBSERVATIONS INDICATE THAT ALMOST ALL PCPN
IS NORTH OF THE CWFA. A FEW SPRINKLES/FLURRIES WILL BE POSSIBLE
THROUGH 10 PM THIS EVENING NORTH OF U.S.-10...HOWEVER THAT WILL BE
INSIGNIFICANT. WE WILL SEE A CLEARING TREND AS THE UPPER LOW PULLS AWAY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 408 PM EDT MON APR 16 2012
MAIN CONCERNS IN THE SHORT TERM PERTAIN TO HEADLINES. NAMELY...THE
WIND ADVISORY THAT IS OUT THROUGH 1000PM AND FROST AND FREEZE
HEADLINES.
REGARDING THE WIND ADVISORY...MAINTAINED IT AS IS...COVERING THE
ENTIRE FORECAST AREA THROUGH 1000PM. LATEST HRRR MODEL CONTINUES
TO INDICATE THE EXPIRATION TIME LOOKS GOOD. STRONG WINDS CONTINUE
THROUGH 800 PM OR SO...THEN DIMINISH STEADILY THEREAFTER. SOLID
PUSH OF COLD AIR ADVECTION IS NOW COMING ACROSS THE LAKE AND
EXPECT STRONG WINDS IN THE COLD AIR ADVECTION TO CONTINUE. GUSTS
OF 45 TO 55 MPH SHOULD CONTINUE THROUGH SUNSET.
WILL BE ISSUING A FREEZE WARNING FOR THE NORTHERN HALF OF THE
FORECAST AREA...MUSKEGON...NEWAYGO...MONTCALM AND CLINTON COUNTIES
NORTHWARD. A FROST ADVISORY FOR OTTAWA...KENT...IONIA AND INGHAM
COUNTIES SOUTHWARD. CLOUDS WILL SCATTER OUT OVERNIGHT AND WINDS
WILL DIMINISH CONSIDERABLY AFTER 06Z. THE COLD AIR ADVECTION ONLY
WILL DRIVE TEMPERATURES TO LEVELS THAT WILL BE A CONCERN TO TENDER
VEGETATION. EXPECTING UPPER 20S FOR LOWS TO THE NORTH AND LOWER
30S TO THE SOUTH.
OTHERWISE...QUIET WEATHER ON TUESDAY WITH SURFACE RIDGING SLIDING
ACROSS THE LOWER PENINSULA. INCREASING CLOUDS ARE EXPECTED TUESDAY
NIGHT AHEAD OF A SHORTWAVE SLIDING EAST IN ZONAL FLOW. KEPT THE
FORECAST DRY AS THE PRECIP SHOULD HOLD OFF INTO WEDNESDAY. ANOTHER
FROST/FREEZE POTENTIAL TUESDAY NIGHT...BUT AN INCREASE WIND AND
CLOUD COVER MAY END THE THREAT. LATER FORECASTS WILL LOOK INTO
THIS THREAT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 408 PM EDT MON APR 16 2012
PROGRESSIVE FLOW WILL BRING ANOTHER NORTHERN STREAM WAVE INTO THE
REGION WED/WED NIGHT. MODEL TRENDS ARE A BIT FASTER...SO HAVE ADDED
POPS TO THE EASTERN CWA LATE WED...THEN REMOVED POPS FOR LATE WED
NIGHT IN THE NW CWA. COULD BE A FEW ISOLATED THUNDERSTORMS WITH
SOME WEAK INSTABILITY.
THE FRONT STALLS JUST TO OUR SOUTH WITH A WAVE OF LOW PRESSURE
TRACKING ALONG IT. THE MODELS ARE TRENDING FURTHER NORTH WITH THIS
LOW...THE GFS COMING MORE IN LINE WITH THE EURO. SO THE SHOWERS
SHOULD RETURN/LINGER INTO THURSDAY/THURSDAY NIGHT. COLD ENOUGH AIR
MAY FILTER IN BEHIND THE LOW...WHERE RAIN COULD MIX WITH SOME SNOW
LATE FRIDAY INTO FRIDAY NIGHT. BUT BY THIS TIME FRAME THE PCPN
SHOULD BE RATHER LIGHT.
THE WEEKEND CONTINUES TO LOOK DRY BUT COOL AS THE PATTERN BECOMES
BLOCKED. THE LOW TO OUR EAST STALLS AND MAY EVEN RETROGRADE A BIT
INTO THE FIRST PART OF NEXT WEEK. HAVE PUT LOW POPS IN FOR THE FAR
SE CWA FOR MON.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 143 AM EDT TUE APR 17 2012
FORECAST CONCERNS TO AVIATION INTERESTS ARE MINIMAL FOR THIS SET
OF FCSTS. SKIES HAVE GENERALLY CLEARED OUT ACROSS THE
AREA...EXCEPT FOR A PATCH OF CLOUDS BASED AROUND 4K FEET NEAR
KGRR. THIS WILL REMAIN AROUND FOR THE NEXT FEW HOURS...BUT THEN
SKIES SHOULD GENERALLY GO CLEAR ONCE AGAIN AND REMAIN THAT WAY
THROUGH TUE. W/NW WINDS WILL REMAIN UP AROUND 5 TO 10 KNOTS THROUGH
THE NIGHT. GRADIENT WILL WEAKEN THROUGH TUE...BUT DIURNAL MIXING
WILL KEEP WIND SPEEDS STEADY. HIGH PRESSURE WILL MOVE OVERHEAD TUE
NIGHT...ALLOWING WINDS TO GO LIGHT AND VARIABLE.
&&
.MARINE...
ISSUED AT 906 PM EDT MON APR 16 2012
WE WENT AHEAD AND DOWNGRADED THE GALE WARNING TO A SMALL CRAFT
ADVISORY AS WINDS HAVE COME DOWN BELOW CRITERIA ALL ALONG THE
COAST. WINDS ARE RIGHT AROUND SMALL CRAFT ADVISORY
CRITERIA...HOWEVER THE WAVES ARE STILL ABOVE THE FOUR FOOT
CRITERIA PER THE MID LAKE BUOY. THE WAVE MODEL INDICATES THAT WE
MAY SEE FOUR FOOTERS REMAIN POSSIBLE INTO THE OVERNIGHT HOURS
BEFORE SUBSIDING. WE RAN THE ADVISORY OUT THROUGH 09Z...AND THIS
SHOULD BE ABLE TO EXPIRE ON TIME WITH THE MORNING FCST PACKAGE.
&&
.HYDROLOGY...
ISSUED AT 408 PM EDT MON APR 16 2012
RAINFALL OVER THE WEEKEND REACHED THE 1.00 TO 2.00 INCH RANGE IN
MANY LOCATIONS. THE HIGHEST TOTAL OCCURRED AT THE SOUTH HAVEN
WATER INTAKE PLANT WHERE 3.02 INCHES OF RAIN WAS MEASURED. THE
HEAVIEST RAINS WERE NOTED ACROSS THE WEST AND SOUTHWEST PORTIONS
OF THE FORECAST AFFECTING THE KALAMAZOO AND ST. JOSEPH RIVER
BASINS THE MOST. AT THIS POINT...RIVERS ARE SHOWING WITHIN BANK
RISES...BUT NO ADVISORIES AND WARNINGS HAVE BEEN ISSUED.
NOT EXPECTING MUCH IN THE WAY OF ADVISORIES OR WARNINGS BASED ON
HOW THE RAIN FELL. IN ADDITION WE ARE LOOKING AT MAINLY DRY
WEATHER THROUGH TUESDAY NIGHT. RAINFALL WITH A FRONT ON WEDNESDAY
SHOULD BE FAIRLY LIGHT AS WELL. RIVERS SHOULD BE ABLE TO STAY
WITHIN BANK OR RECEDE THROUGH MID WEEK AT MOST LOCATIONS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR MIZ056>059-
064>067-071>074.
FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR MIZ037>040-
043>046-050>052.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EDT EARLY THIS MORNING FOR
LMZ844>849.
&&
$$
UPDATE...NJJ
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...JK
AVIATION...NJJ
HYDROLOGY...DUKE
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
306 AM EDT TUE APR 17 2012
.SYNOPSIS...
A COLD FRONT WILL CLEAR SOUTHEAST PENNSYLVANIA OVERNIGHT. HIGH
PRESSURE WILL BUILD SOUTHEAST ACROSS THE AREA FOR MID WEEK. A
DEEPENING TROUGH WILL LIKELY FORM OVER THE EASTERN CONUS BY THE
WEEKEND OR EARLY NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
COLD FRONT PUSHING INTO EXTREME EASTERN PA AT 05Z. WILL REMOVE
LAST MENTION OF SHRA FROM THE FCST...AS MUCH DRIER AIR IS NOW
WORKING INTO CENTRAL PA ON A GUSTY WNW WIND. TIGHT PRES GRADIENT
WILL REMAIN OVER THE AREA...LEADING TO BREEZY CONDS EARLY THIS
MORNING. BLEND OF RUC13 AND LAMP GUIDANCE INDICATE TEMPS SHOULD
BOTTOM OUT AT DAWN FROM THE L40S NW MTNS...TO THE U50S ACROSS THE
LOWER SUSQ VALLEY. UPSTREAM SATL IMAGERY AND MDL DATA BOTH SUGGEST
AN INCREASE IN HIGH CLOUDS TOWARD DAWN OVER THE CENTRAL MTNS...AS
CIRRUS STREAMS NORTH FROM DEVELOPING WAVE OVR THE SOUTHEAST CONUS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
00Z MDLS NOW INDICATE A FAIR AMT OF CIRRUS WILL BE OVER CENTRAL
AND WESTERN PA LATER TODAY...AS HIGH LVL MOISTURE CONTINUES TO
STREAM NORTH FROM DEVELOPING WAVE OVR THE SE CONUS. WILL TERM SKY
COVER AS /PTSUNNY/ FOR MOST OF THE REGION AND HAVE LEANED TOWARD
THE SLIGHTLY COOLER MAV NUMBERS WITH MAX TEMPS FROM THE M50S NW
MTNS...TO L70S LOWER SUSQ VALLEY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
NOT A LOT OF CHANGE FROM YESTERDAY. MAIN THING WAS TO BACK OFF
THE COLD AIR AND MENTION OF SNOW FOR THE WEEKEND.
STILL A LOT OF SPREAD IN THE FCST FOR THE WEEKEND AND EARLY
NEXT WEEK. GFS AND HPC CHARTS NOW HAVE IN MORE IN THE MILDER
AIR BEFORE LATER SUNDAY INTO MONDAY. CUTOFF NOW FORMS FURTHER
SOUTH NOW...AND LATER IN TIME.
ASIDE FROM THE WEEKEND...LEFT THINGS CLOSE TO WHAT WE HAD.
FOR TUESDAY NIGHT...MODELS NOT SO COLD NOW...BUT STILL DOWN
NEAR FREEZING OR JUST BELOW ACROSS NORTHERN PA AND SOUTHERN
NY...BUT FOR NOW HELD OFF ON FREEZE WATCH.
FOR WED...DID EDGE TEMPS DOWN ACROSS THE SOUTH...EXPECT MORE
CLDS. WENT WITH A DRY FCST FOR WED. GFS FURTHER NORTH WITH
MOISTURE...BUT THE AIRMASS THAT COMES IN LATE TONIGHT IS
QUITE DRY.
DID EDGE POPS OFF ON THU AND FRIDAY...MODELS FURTHER NORTH
NOW WITH THE MOISTURE.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS EXPECTED TO CONTINUE OVERNIGHT. GUSTY WINDS WILL GRADUALLY
SHIFT TO THE WEST BEFORE DIMINISHING BY 09Z AS THE REGION DECOUPLES.
WHILE THE GRADIENT SLACKENS A LITTLE TONIGHT AND TUES...DAYTIME
MIXING TUES COULD STILL MAKE GUSTS INTO THE 20-25KT RANGE ONCE
AGAIN. OTHERWISE VFR AS THE HIGH PRESSURE BUILDS IN. CLEAR AND
CALM TUES NIGHT.
OUTLOOK...
WED-FRI...VFR. MAY SEE SOME SHRA FRI AS NEXT FRONT APPROACHES.
SAT...MVFR CIGS/VIS IN SHRA.
&&
.FIRE WEATHER...
TUESDAY WILL FEATURE LOWER WIND SPEEDS AND GUSTS AS THE GRADIENT
SLACKENS A BIT WITH APPCH OF HIGH PRES. HOWEVER...THE RH/S WILL
EASILY GET BELOW 30PCT OVER ALL OF THE AREA. WINDS WILL BE THE
DECIDING FACTOR...AND TUESDAY MORNING SHIFT WILL CONSULT WITH FORESTRY
OFFICIALS ON ANY RED FLAG CONCERNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/MARTIN
NEAR TERM...FITZGERALD
SHORT TERM...DANGELO/FITZGERALD
LONG TERM...MARTIN
AVIATION...LA CORTE/CERU
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1151 PM CDT MON APR 16 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
319 PM CDT MON APR 16 2012
MAIN FORECAST CONCERNS ARE ON FREEZE TONIGHT AND PRECIPITATION
CHANCES FOR TUESDAY NIGHT...WEDNESDAY AND AGAIN THURSDAY.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S....TROUGHING FROM ONTARIO INTO
TEXAS AND RIDGING ALONG THE EAST COAST OF THE U.S.. WITHIN THE
TROUGHING...A POTENT SHORTWAVE TROUGH WAS OVER UPPER MICHIGAN WHICH
HAS BEEN RESPONSIBLE FOR THE WINDY CONDITIONS LATELY...WHILE ANOTHER
SHORTWAVE WAS NEAR SIOUX FALLS SOUTH DAKOTA. THIS LATTER SHORTWAVE
WAS NOT DOING MUCH PRECIPITATION WISE...BUT THERE IS A DEFINITE BAND
OF LOW TO MID LEVEL CLOUDS COVERING MUCH OF THE DAKOTAS INTO
SOUTHWEST MINNESOTA. 12Z BIS SOUNDING WAS NEARLY SATURATED FROM 925
TO 700MB...SO THE SHORTWAVE DOES APPEAR TO BE SPREADING AT LEAST
CLOUDS EASTWARD. AHEAD OF THESE CLOUDS AND IN THE WAKE OF THE POTENT
TROUGH...THERE IS SOME CLEARING DROPPING DOWN THROUGH NORTHERN AND
CENTRAL MINNESOTA. WINDS ARE SLOWLY DIMINISHING ACROSS THE AREA DUE
TO A WEAKENING PRESSURE GRADIENT. SURFACE PRESSURE ANALYSIS SHOWED A
997MB LOW WAS LOCATED OVER THE EASTERN UPPER PENINSULA WHILE A RIDGE
OF HIGH PRESSURE WAS OVER THE DAKOTAS. THE WINDY NORTHWEST WINDS
HAVE DROPPED 850MB TEMPS DOWN TO -4 TO -8C OVER THE FORECAST AREA
PER RUC ANALYSIS...AND -10 TO -12C OVER NORTHERN WISCONSIN. THIS
COLD AIR LED TO SOME STRAIGHT SNOW OR RAIN/SNOW MIX OVER NORTHERN
PORTIONS OF THE FORECAST AREA THIS MORNING. 850MB TEMPS NOT MUCH
WARMER OVER THE DAKOTAS EITHER...-2 TO -6C...CONFIRMED TOO BY 12Z
RAOBS.
TONIGHT AND TUESDAY...UPPER LEVEL FLOW IS PROGGED TO BECOME MORE
ZONAL DURING THIS PERIOD AS A SHORTWAVE OFF THE PACIFIC NORTHWEST
COAST PLOWS INLAND ACROSS THE NORTHERN ROCKIES. FOR OUR AREA...WE
WILL HAVE A FEW SHORTWAVES MOVE THROUGH...THE FIRST OF WHICH IS THE
ONE NEAR SIOUX FALLS CROSSING THIS EVENING...THEN ANOTHER MUCH
WEAKER ONE SEEN ON WATER VAPOR OVER EASTERN MONTANA WHICH COMES
THROUGH TUESDAY MORNING. AGAIN...NOT ANTICIPATING ANY PRECIPITATION
WITH EITHER SHORTWAVE BECAUSE OF A LACK OF BOTH DYNAMICAL AND
ISENTROPIC LIFT. THEY WILL...HOWEVER...BRING AN INCREASE OF LOW TO
MID LEVEL STRATUS. SO AFTER WHAT COULD BE A BRIEF PERIOD OF CLEARING
THIS EVENING...MAINLY NORTH OF I-94 ASSOCIATED WITH THAT CLEARING
DROPPING DOWN THROUGH CENTRAL MINNESOTA...EXPECTING SKIES TO AT
LEAST TURN MOSTLY CLOUDY. LIKELY THE STRATUS SHOULD CLEAR OUT IN THE
WAKE OF THE SECOND SHORTWAVE...BUT THIS APPEARS BRIEF AS WELL.
LOOKING AT TUESDAY AFTERNOON...290-300 K ISENTROPIC LIFT REALLY
INCREASES DOWNSTREAM OF THAT SHORTWAVE COMING INTO THE ROCKIES...
RESULTING IN MORE MID LEVEL STRATUS. LIFT DOES NOT LOOK STRONG
ENOUGH TO PRODUCE PRECIPITATION...THOUGH. ALL OF THESE CLOUD
TRANSITIONS MAKE THE TEMPERATURE FORECAST DIFFICULT. IF IT WERE
CLEAR TONIGHT...THE SURFACE RIDGE MOVING IN AND HAVING 850MB TEMPS
IN THE 0 TO -6C RANGE IN PLACE WOULD BE VERY FAVORABLE FOR
TEMPERATURES TO PLUMMET WELL BELOW FREEZING. WITH THE CLOUDS MOVING
THROUGH TONIGHT...GENERALLY FOLLOWED CLOSE TO A BLEND OF THE 16.12Z
NAM12/16.09Z SREF MEAN. THE LOWS PROMPT THE NEED FOR A FREEZE
WARNING ALONG/NORTH OF I-94. LOWS MAY DIP TO FREEZING
ELSEWHERE...SUCH AS LA CROSSE...BUT CONFIDENCE IS NOT HIGH ENOUGH TO
ISSUE FREEZE WARNING DUE TO THE CLOUDS. FOR TUESDAY...RETURN FLOW
DOES HELP TO BOOST 850MB TEMPS UP TO 2-6C BY 00Z WEDNESDAY...BUT
TEMPERATURES WILL BE HELD BACK SOMEWHAT DUE TO THE CLOUDS. FOLLOWED
GENERALLY A BLEND OF GUIDANCE FOR HIGHS.
TUESDAY NIGHT AND WEDNESDAY...FOCUS IS ON THAT SHORTWAVE COMING OUT
OF THE ROCKIES. VERY GOOD MODEL AGREEMENT EXISTS THAT AS THE
SHORTWAVE CROSSES THE DAKOTAS AND LIFTS INTO FAR NORTHERN WISCONSIN
WEDNESDAY MORNING...IT WILL DEEPEN. IN RESPONSE TO THIS DEEPENING...
A STRONG SURGE OF SOUTHWEST 850MB MOISTURE TRANSPORT/ISENTROPIC LIFT
ON THE 290-295K SURFACE COMES ACROSS THE AREA TUESDAY EVENING.
SHOULD SEE SOME SHOWERS FALL IN THE EVENING. THERE IS SOME WEAK
CAPE...LESS THAN 200 J/KG...ENOUGH TO WARRANT A THUNDER MENTION.
AFTER MIDNIGHT INTO WEDNESDAY MORNING...THE COMBINATION OF HEIGHT
FALLS ALOFT WITH THE APPROACHING SHORTWAVE AND A PERSISTENT FLOW OF
850MB MOISTURE TRANSPORT SHOULD LEAD TO THE DEVELOPMENT OF A WARM
CONVEYOR BELT OF SHOWERS AND EMBEDDED THUNDERSTORMS. GIVEN DECENT
COVERAGE OF PRECIPITATION DEVELOPMENT...CAPE SHOULD STAY LIMITED AT
LESS THAN 500 J/KG...LIMITING ANY CHANCE FOR SEVERE WEATHER. THIS
WARM CONVEYOR BELT WILL TRACK WEST TO EAST ACROSS THE AREA THROUGH
WEDNESDAY MORNING. GIVEN GOOD MODEL CONSENSUS FOR PRECIPITATION...
HAVE RAISED PRECIPITATION CHANCES UP TO 80 PERCENT. A DRY SLOT THEN
ENTERS THE PICTURE FOR LATE WEDNESDAY MORNING INTO THE AFTERNOON...
PUNCHING IN FROM THE WEST IN THE WAKE OF THE SHORTWAVE TROUGH
LIFTING OFF TO THE NORTHEAST. THIS DRY SLOT SHOULD END PRECIPITATION
AND LIKELY RESULT IN A DECREASE IN CLOUDS. MUCH WARMER CONDITIONS
ANTICIPATED TUESDAY NIGHT WITH LOWS IN THE EVENING...THEN CLIMBING
SLIGHTLY AFTER MIDNIGHT WITH THE MOISTURE TRANSPORT SURGE. WARMER
850MB TEMPS OF 4-8C ON WEDNESDAY...PLUS SUN...WILL ALLOW FOR HIGHS
IN THE 60S TO EVEN 70.
WEDNESDAY NIGHT AND THURSDAY...THIS PERIOD FOCUS IS ON A COLLECTIONS
OF SHORTWAVES PROGGED TO MOVE INTO THE NORTHERN ROCKIES LATE
WEDNESDAY. HEIGHT FALLS DOWNSTREAM OF THESE SHORTWAVES HELP DEVELOP
A SURFACE LOW IN SOUTHEAST COLORADO. GOOD MODEL CONSENSUS EXISTS
THAT THE COLLECTION OF SHORTWAVES WILL DIG DOWN INTO THE CENTRAL
PLAINS WEDNESDAY NIGHT...LEADING TO A SHIELD OF DPVA AND DEFORMATION
FORCED PRECIPITATION DOWNSTREAM. AT THIS TIME IT APPEARS ANY
PRECIPITATION SHOULD HOLD OFF UNTIL THURSDAY. THERE ARE SOME ISSUES
THAT REMAIN FOR THURSDAY...THOUGH. ALTHOUGH GREAT MODEL AGREEMENT
EXISTS BETWEEN THE 16.12Z GFS/NAM/ECMWF/CANADIAN THAT MUCH OF THE
AREA SEES THAT DPVA AND DEFORMATION PRECIPITATION...THE
ECMWF/CANADIAN REMAIN FARTHER NORTH WITH THE ASSOCIATED SURFACE
SYSTEM. IF THESE HOLD TRUE...THUNDER CHANCES WOULD BE REQUIRED FOR
AT LEAST LOCATIONS SOUTH OF I-90. FOR NOW HAVE KEPT THUNDER OUT
GIVEN THAT IT RECENTLY WAS AND THE PERSISTENCE FOR MORE SOUTHERN
SOLUTIONS...BUT THIS WILL NEED TO BE WATCHED. CERTAINLY POTENTIAL
HERE FOR SOME DECENT QPE VALUES TOO...WITH CURRENT FORECAST QPF
ANYWHERE FROM 0.25 TO 0.75 INCHES.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
319 PM CDT MON APR 16 2012
GOOD AGREEMENT REMAINS AMONGST 16.12Z GFS/ECMWF/CANADIAN AND GFS
ENSEMBLES ON SHOWING MAJOR AMPLIFICATION WITH THE UPPER FLOW DURING
THE LONG TERM PERIOD. RIDGING IN THE WESTERN U.S. DEVELOPS THURSDAY
NIGHT THROUGH SATURDAY WHILE A POTENT SHORTWAVE RIDES DOWN THE
RIDGE...FORMING A DEEP TROUGH OVER THE SOUTHEASTERN U.S. BY SATURDAY
NIGHT. BY MONDAY...A BLOCKED UP PATTERN IS FORECAST WITH STRONG
RIDGING OVER THE WESTERN U.S. AND A WIDE/DEEP CUT-OFF UPPER LOW OVER
THE EASTERN U.S.. THIS MEANS A COOL PATTERN FOR THE FORECAST
AREA...THOUGH OVERALL RELATIVELY DRY. REALLY ONLY PRECIPITATION TO
SPEAK OF IS THURSDAY NIGHT...ASSOCIATED WITH DEFORMATION AND DPVA
INDUCED RAIN FROM THURSDAY SLOWLY EXITING. ENOUGH COLD AIR DOES WRAP
DOWN INTO THE AREA FOR A MIX OR CHANGE OVER TO SNOW...THOUGH IT IS
CONCEIVABLE THE PRECIPITATION ENDS BEFORE THE COLDER AIR ARRIVES.
ALSO HAVE A SLIGHT CHANCE OF RAIN SHOWERS IN FOR SATURDAY NIGHT
WHERE THERE ARE SUGGESTIONS OF A SHORTWAVE DROPPING DOWN INTO THE
EASTERN TROUGH. ONLY KEPT AT 20 PERCENT GIVEN VERY FEW MODELS HAVE
THIS PRECIPITATION. IN FACT...LATER FORECASTS MAY BE ABLE TO PULL
THIS IF ALL MODELS TREND TOWARD THE ECMWF/GFS. OTHERWISE...
TEMPERATURES ARE THE STORY WHICH AGAIN LOOK TO HOLD BELOW NORMAL. IN
ADDITION...COULD BE DEALING WITH FREEZE WARNINGS FOR FRIDAY NIGHT
AND POSSIBLY SATURDAY NIGHT AS WELL...IF THE PRECIPITATION DOES NOT
MATERIALIZE. BEST CHANCE FOR FREEZE IS AGAIN ALONG AND NORTH OF
I-94. PERHAPS TOWARDS MONDAY WE WILL BE ABLE TO CLIMB BACK TO NEAR
OR ABOVE NORMAL WITH HINTS OF THE UPPER RIDGE TRYING TO BUILD
TOWARDS THE AREA.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1151 PM CDT MON APR 16 2012
A MID TO HIGH DECK OF VFR CEILINGS WERE FOUND AT THE TAF SITES AT
05Z. SATELLITE TRENDS WERE SHOWING A GRADUAL DECREASE IN THE
CLOUDS ACROSS THE AREA AND MODEL SOUNDINGS ALSO INDICATING THIS
TREND. THUS DID SCATTERED OUT THE CEILINGS BETWEEN 06Z-09Z AT BOTH
SITES. VFR CONDITIONS THEN WILL PREVAIL THROUGH THE REMAINDER OF
THE FORECAST PERIOD. VFR CEILINGS LOOK TO RETURN LATER TODAY AHEAD
OF THE NEXT SYSTEM PUSHING THROUGH THE PLAINS. CEILINGS WILL
GRADUALLY LOWER TO AROUND 4K FEET AT KRST BY 04Z...WITH THE
POSSIBILITY OF A FEW SHOWERS FROM 04Z-06Z AT KRST AND DID INTRODUCED
VCSH IN THIS TIME FRAME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
319 PM CDT MON APR 16 2012
WI...FREEZE WARNING FROM 1 AM TO 8 AM CDT TUESDAY FOR WIZ017-029-034-
042>044.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
612 AM CDT TUE APR 17 2012
...UPDATE TO AVIATION...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 346 AM CDT TUE APR 17 2012
PATCHY DENSE FOG HAS DEVELOPED OUT ALONG AND WEST OF A LINE FROM SCOTT
CITY AND GARDEN CITY DOWN TOWARD MEADE. MSAS/RUC ANALYSIS IS SHOWING
A SWATH OF LOW DEWPOINT DEPRESSION LINING UP WELL WITH THE FOG. SO FAR
THE FOG HAS REMAINED FAIRLY PATCHY AS INDICATED ON THE 11-3.9 MICRON
SATELLITE CHANNEL. MODEL SOUNDINGS SHOW MOISTURE TO BE VERY SHALLOW
AND THE SURFACE VISIBILITY FORECAST FROM THE HRRR IS TRENDING AWAY
FROM DEVELOPING WIDESPREAD LOW VISIBILITIES THIS MORNING. CURRENT
THINKING IS TO HANDLE THE FOG WITH A MENTION OF PATCHY DENSE IN
THE GRIDS AND NOWCAST IT THROUGH SUNRISE. IF DENSE FOG BECOMES
MORE WIDESPREAD MAY NEED TO ISSUE AN ADVISORY. THE FOG SHOULD BE
FAIRLY QUICK TO BURN OFF TODAY AS LOW LEVEL MIXING ENSUES AND
SOUTH TO SOUTHWEST WINDS INCREASE.
SHORTWAVE RIDGING OVER THE CENTRAL HIGH PLAINS EARLY THIS MORNING WILL
MOVE EAST TODAY WITH ZONAL FLOW SPREADING EASTWARD FROM THE ROCKIES
TODAY AND TONIGHT. GOOD MIXING TODAY WILL RESULT IN TEMPERATURES
CLIMBING INTO THE 70S...WITH UPPER 70S IN THE WEST. THE DEEP MIXING
SHOULD PUSH RELATIVE HUMIDITY LEVELS DOWN INTO THE UPPER TEENS OVER
FAR SOUTHWEST KANSAS. THE LOW RH`S SHOULD BE ATTENUATED SOMEWHAT
BY THE ONGOING GREENUP AND INCREASED EVAPOTRANSPIRATION SO ANY
SIGNIFICANT FIRE WEATHER ISSUES ARE NOT ANTICIPATED.
SOME SCATTERED CIRRUS WILL PASS OVER WESTERN KANSAS TONIGHT AS THE
AFOREMENTIONED SHORTWAVE MOVES EAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 400 AM CDT TUE APR 17 2012
MEDIUM RANGE MODELS INDICATE A ZONAL FLOW ALOFT PERSISTING ACROSS
THE WESTERN HIGH PLAINS TO BEGIN THE PERIOD WEDNESDAY. MEANWHILE, AN
UPPER LEVEL SHORTWAVE TROUGH WILL TRANSITION EAST FROM THE NORTHERN
PLAINS INTO THE GREAT LAKES REGION. A FAIRLY WEAK ATTENDANT COLD
FRONT IS EXPECTED TO PUSH JUST INTO NORTHWESTERN KANSAS BEFORE
STALLING OUT, POSSIBLY JUST INTO NORTHERN PORTIONS OF SOUTHWEST
KANSAS AND PORTIONS OF CENTRAL KANSAS JUST SOUTH OF THE I-70
CORRIDOR. HOWEVER, NO SIGNIFICANT PRECIPITATION IS EXPECTED WITH
THIS FRONT WITH A GENERALLY WEAK FLOW ALOFT. HOWEVER, THE CHANCES
FOR PRECIP DO PICK UP A LITTLE THURSDAY AS ANOTHER UPPER LEVEL
SHORTWAVE IS PROGGED TO SWING ACROSS THE WESTERN PLAINS. AN
ATTENDANT COLD FRONT TO THIS SYSTEM WILL PUSH SOUTHEAST WELL INTO
AND ACROSS WESTERN KANSAS DURING THE DAY THURSDAY BRINGING THE
CHANCE FOR SHOWERS AND A FEW THUNDERSTORMS TO PORTIONS OF WESTERN
KANSAS BY THURSDAY EVENING. HOWEVER, HOW STRONG ANY POSSIBLE STORMS
MAY BE REMAINS UNCERTAIN. NAM AND GFS MODEL SOUNDINGS HINT AT A
POSSIBLE LACK OF LOW LEVEL MOISTURE ALONG WITH LESS THAN FAVORABLE
INSTABILITY LEVELS. ADDITIONALLY, TIMING OF THE FRONT COULD BE AN
ISSUE AS WELL WITH ALL MODELS PROJECTING THE FRONTAL PASSAGE TO TAKE
PLACE EARLIER IN THE DAY. LOW END CHANCE CATEGORY POPS SEEM
REASONABLE AT THIS POINT. DRIER CONDITIONS ARE THEN EXPECTED
THROUGH THE WEEKEND AND INTO THE EARLY PART OF NEXT WEEK AS UPPER
LEVEL RIDGING DEVELOPS AND PUSHES EAST ACROSS THE INTERMOUNTAIN
WEST.
TEMPERATURES ARE EXPECTED TO BE JUST ABOVE NORMAL WEDNESDAY AS A
ZONAL FLOW PERSISTS ACROSS THE WESTERN HIGH PLAINS. A LEE SIDE
TROUGH OF LOW PRESSURE IS EXPECTED TO REDEVELOP ACROSS EASTERN
COLORADO RETURNING A LOW LEVEL SOUTHERLY FLOW TO SOUTHWESTERN AND
SOUTH CENTRAL KANSAS BY LATE AFTERNOON. THE NAM, GFS, AND ECMWF SHOW
H85 TEMPERATURES IN THE MID TO UPPER TEENS(C) ACROSS CENTRAL KANSAS
TO THE LOWER 20S(C) ACROSS SOUTHWESTERN KANSAS. WITH LOWER LEVEL DRY
LAPSE RATES LIKELY BY WEDNESDAY AFTERNOON, LOOK FOR HIGHS UP INTO
THE UPPER 70S(F) TO THE LOWER TO MID 80S(F). A GENERAL COOLING TREND
IS LIKELY THROUGH THE END OF THE WEEK AS MUCH COOLER AIR SURGES
SOUTH INTO WESTERN KANSAS IN WAKE OF THE COLD FRONTAL PASSAGE
THURSDAY. HIGHS COULD STRUGGLE TO REACH THE 70S(F) THURSDAY
DEPENDING ON ANY CLOUD COVER ASSOCIATED WITH THE COLD FRONT
AND THE TIMING OF THE PASSAGE ITSELF.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 605 AM CDT TUE APR 17 2012
AREAS OF FOG HAVE DEVELOPED THIS MORNING ACROSS PORTIONS OF
SOUTHWEST KANSAS...INCLUDING IN THE VICINITY OF KGCK. PERIODS OF
IFR CIGS/VSBYS WILL CONTINUE IN THE VICINITY OF KGCK AND POSSIBLY
KDDC THROUGH MID MORNING. OTHERWISE, VFR CONDITIONS ARE EXPECTED
AT ALL TAF SITES FROM MID MORNING THROUGH LATE THIS EVENING. AS
FOR WINDS, A LEE SIDE TROUGH OF LOW PRESSURE WILL DEVELOP AND
STRENGTHEN ACROSS EASTERN COLORADO TODAY. AS A RESULT, LIGHT
SOUTHERLY WINDS EARLY THIS MORNING WILL INCREASE UP TO 15 TO
25KT BY EARLY THIS AFTERNOON. WINDS WILL THEN SUBSIDE THIS
EVENING BUT REMAIN SOUTHERLY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 76 49 81 53 / 0 10 0 0
GCK 74 46 81 50 / 0 0 0 0
EHA 76 47 83 51 / 0 0 0 0
LBL 77 48 84 53 / 0 10 0 0
HYS 73 49 78 52 / 0 10 0 0
P28 73 53 81 55 / 0 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CDT /9 AM MDT/ THIS MORNING FOR
KSZ043-044-061>063-075>078-086>088.
&&
$$
SHORT TERM...GERARD
LONG TERM...JJOHNSON
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1050 AM EDT TUE APR 17 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR DRY WEATHER THROUGH FRIDAY. A COLD
FRONT APPROACHING FROM THE WEST WILL RETURN THE CHANCE OF SHOWERS
AND THUNDERSTORMS LATE FRIDAY AND INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY IN A
SOUTHWESTERLY FLOW WITH A BROAD AND WEAK TROUGH ACROSS THE GREAT
LAKES. AT THE SURFACE, HIGH PRESSURE IS CENTERED ACROSS LAKE
MICHIGAN AND EXTENDS ACROSS THE OHIO VALLEY. MID TO UPPER LEVEL
MOISTURE IS FILTERING IN FROM THE SOUTHWEST, ALLOWING FOR PARTLY
CLOUDY SKIES.
MOISTURE ALOFT WILL CONTINUE TO FILTER IN FROM THE SOUTHWEST AND ALLOW
FOR PARTLY CLOUDY SKIES TODAY. TEMPS TODAY ARE NEAR LAMP
GUIDANCE, WITH HIGHS RANGING FROM THE MID 50S ALONG THE I-80
CORRIDOR AND EASTERN RIDGES TO THE MID 60S SOUTHWEST OF
PITTSBURGH.
MID-LEVEL FLOW WILL FLATTEN AND BECOME MORE ZONAL THROUGH
TONIGHT, WITH HIGH PRESSURE SLIDING ACROSS THE GREAT LAKES. THE
LOBE OF HIGH PRESSURE IS PROGGED TO BE CENTERED ACROSS LAKE
ONTARIO BY 12Z WEDNESDAY. 500-250MB LAYER MOISTURE SHOULD PROVIDE
ENOUGH CLOUD COVERAGE TO LIMIT RADIATIONAL COOLING. LOWS TONIGHT
ARE CLOSER TO THE WARMER MAV GUIDANCE, RANGING FROM THE MID 30S
ALONG THE I-80 CORRIDOR TO THE MID 40S ACROSS NORTH-CENTRAL WV.
THE I-80 CORRIDOR IS CURRENTLY MARGINALLY WARMER THAN FREEZING FOR
LOWS, SO WILL NOT ISSUE A FREEZE WARNING AT THIS TIME.
&&
.SHORT TERM /WEDNESDAY/...
RECENT SREF MODEL OUTPUT SHOWS SURFACE HIGH PRESSURE, COMING EAST
FROM IOWA, CONTINUING DRY CONDITIONS FOR MOST OF THE UPPER OHIO
VALLEY THROUGH WEDNESDAY.
A COUPLE SREF MEMBERS SHOW LOW PRESSURE MOVING NORTHEASTWARD THROUGH
THE MID-ATLANTIC STATES AND PERHAPS SPREAD ISOLATED LIGHT SHOWERS
ACROSS THE WV-MD MOUNTAINS DAYTIME WEDNESDAY.
TEMPERATURES SHOULD CONTINUE TO REMAIN CLOSE TO NORMAL VALUES BASED
OFF OF THE MOST RECENT MAV/MEX GUIDANCE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
RECENT SREF MODEL OUTPUT SHOWS EASTBOUND LOW PRESSURE THROUGH THE
GREAT LAKES PERHAPS LAYING A STALLED COLD FRONT ACROSS NORTHERN
PENNSYLVANIA THURSDAY. EXPECT LITTLE SHOWER DEVELOPMENT BUT AN
INCREASE IN CLOUDS THURSDAY INTO FRIDAY.
BLEND OF RECENT ECMWF, GFS, AND CMC, SHOW A BETTER DEVELOPED LOW
PRESSURE SYSTEM, COMING EAST FROM THE NORTHERN ROCKIES, WILL PROVIDE
THE UPPER OHIO VALLEY WITH SHOWERS AND POSSIBLE THUNDERSTORMS LATE
FRIDAY INTO SUNDAY.
GFS MOS AND NAEFS MEDIAN VALUES SHOW WARMER THAN NORMAL TEMPERATURES
INTO SATURDAY, FOLLOWED BY A POST-SYSTEM COOL DOWN TO SEASONABLE
TEMPERATURES SUNDAY AND MONDAY.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
EXPECT VFR TO CONTINUE THROUGH TONIGHT, WITH LITTLE MORE THAN
PASSING STRANDS OF ALTOCUMULUS AND CIRRUS.
SURFACE WINDS WILL REMAIN NORTHWESTERLY 8 TO 15 KTS INTO EVENING,
THEN DECREASE TO 5 KTS.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
VFR INTO FRIDAY. RESTRICTIONS LIKELY FRIDAY NIGHT AND SATURDAY FROM
PREFRONTAL SHOWERS AND POSSIBLE THUNDERSTORMS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
725 AM EDT TUE APR 17 2012
.SYNOPSIS...
ISSUED AT 443 AM EDT TUE APR 17 2012
00Z RAOBS/LATEST WV IMAGERY AND LATEST RUC ANALYSIS SHOW SHRTWV
RESPONSIBLE FOR WINTRY MIX/GUSTY WINDS YDAY SHEARING ENEWD OVER
ONTARIO ON NW FLANK OF SHARP UPR RDG OFF THE SE COAST. ALTHOUGH
ASSOCIATED SFC LO IS WEAKENING AND MOVING QUICKLY TO THE E THRU
QUEBEC...SOME SHSN ARE FALLING OVER THE NCNTRL AND E AS OF MIDNGT
UNDER THE WEAKENING BUT LINGERING CYC NW FLOW LEFT IN ITS WAKE.
00Z H85 TEMPS AS LO AS -11C PER RUC ANALYSIS AND CONSIDERABLE
LLVL MSTR/INVRN BASE ARND H85 SHOWN ON THE 00Z APX RAOB ARE
CONDITIONS CONDUCIVE FOR THIS BIT OF LATE SEASON LES AND EXTENSIVE
LK SC. UNDER THE H85 THERMAL TROF...SFC TEMPS ARE QUITE CHILLY WITH
TEMPS GENERALLY IN THE 20S. ALTHOUGH PTCHY LO CLDS ARE STILL PRESENT
AS FAR W AS THE MN ARROWHEAD...ANY LINGERING PCPN IS ENDING OVER THE
W WITH APRCH OF TRAILING HI PRES RDG AND VERY DRY AIR SHOWN ON THE
00Z INL RAOB /PWAT 0.13 INCH/. LOOKING FARTHER W...AN UPPER RDG IS
BLDG INTO THE PLAINS WITH 12Z-24Z H3 RISES ARND 150M OVER THE NRN
PLAINS AND S OF NRN BRANCH TROF OVER CENTRAL CANADA. 00Z BISMARCK
RAOB DOES SHOW SOME MSTR THAT SUPPORTED A GOOD AMOUNT OF SC IN THE
NRN PLAINS YDAY. ANOTHER SHRTWV IS MOVING ONSHORE IN THE PAC NW.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 443 AM EDT TUE APR 17 2012
MAIN FCST CONCERNS DURING THIS TIME ARE PCPN TRENDS EARLY THIS
MRNG...TEMPS TODAY...AND THEN PCPN CHCS LATE TNGT THRU WED
ASSOCIATED WITH SHRTWV NOW MOVING THRU THE PAC NW.
EARLY THIS MRNG...AS SHRTWV/SFC LO TO THE E CONTINUE TO SLIDE AWAY
AND HI PRES BUILDS INTO THE WRN CWA BY 09Z UNDER STEADY H5
RISES/DNVA THAT IS FCST TO LOWER INVRN BASE TO UNDER 3K FT AT ERY BY
09Z. SO ALTHOUGH QUITE A BIT OF SC WILL LINGER...EXPECT ANY -SHSN TO
BE OVER BY 12Z. LINGERING SC OVER MUCH OF THE CWA WL LIMIT
ADDITIONAL DIURNAL TEMP DROP.
TODAY...WITH HI PRES/DRY AIRMASS PUSHING E ACROSS THE CWA...EXPECT
LAKE EFFECT SC IN THE MRNG TO DISSIPATE IN THE PRESENCE OF DAYTIME
HEATING AND WEAKENING CYC FLOW. BUT WITH HINT OF LINGERING H85
THERMAL TROF AND ARRIVAL OF SOME MSTR SHOWN ON THE 00Z BISMARCK
RAOB...MORE DIURNAL CU/SC SHOULD DVLP OVER MAINLY THE W HALF
INTERIOR INLAND AWAY FM LK BREEZES THAT FORM IN THE RELATIVELY WEAK
PRES GRADIENT. MIXING TO H85-8 ON NAM FCST SDNGS YIELD HI TEMPS
RANGING FM ARND 40 AT ERY TO THE UPR 40S NEAR THE WI BORDER. WITH LK
BREEZE FORMATION...EXPECT COOLER READINGS NEAR THE LK SHORES.
TNGT...LATEST NUMERICAL MODELS IN GOOD AGREEMENT SHOWING SHRTWV NOW
IN THE PAC NW/ACCOMPANYING SFC LO MOVING THRU THE NRN PLAINS AND
INTO NE MN BY 12Z WED...WITH WAD PCPN IN ADVANCE OF THIS FEATURE
OVERSPREADING THE W HALF OF UPR MI BY SUNRISE. MAIN FORCING
MECHANISMS LOOK TO BE VIGOROUS UPR DVGC IN LEFT EXIT OF SUPPORTING
H3 JET MAX/VIGOROUS ISENTROPIC ASCENT POWERED BY H85 SW 50-60KT
WINDS/VIGOROUS H85-7 FGEN IN ADVANCE OF ATTENDANT WARM FNT. OPTED TO
BUMP POPS UP TO CATEGORICAL OVER THE W AFT 06Z GIVEN THESE POTENT
DYNAMICS/IMPRESSIVE DEEP LYR QVECTOR CNVGC/MODEL CONSISTENCY ON
GENERATING PCPN IN THIS AREA. ALTHOUGH FCST H100-85 THKNS AS HI AS
1320-1335M IN ADVANCE OF PCPN ARRIVAL...RAPID ARRIVAL OF WAD
CLD...FASTER ADVECTION OF HIER LLVL SPECIFIC HUMIDITY THAN EARLIER
FCSTS INDICATED...ONSET OF STRONGER WINDS INDICATE PCPN SHOULD BE
ALL RA...INITIAL RELATIVE DRYNESS OF LLVLS THAT LOWERS WBLB TO BLO
32 AT THE SFC SUPPORTS MAINTAING A MENTION OF A BIT OF -FZRA AT THE
ONSET OF THE RA SHIELD OVER THE INTERIOR. ANY ICING WOULD BE
INSIGNIFICANT DUE TO STEADY WARMING SOON AFT PCPN ARRIVAL. UTILIZED
A NON-DIURNAL TEMP CURVE TO HANDLE TEMP TRENDS. TEMPS WL BE LOWEST
AND SINK BLO 32 OVER THE E...BUT PCPN WL NOT GET THERE BEFORE
SUNRISE. ALTHOUGH GFS/NAM SHOW LAPSE RATES NOT MUCH STEEPER THAN
MOIST ADIABATIC/ MUCAPE UNDER 50 J/KG...RETAINED MENTION OF SCHC TS
GIVEN VIGOROUS DYNAMICS/STRONG WARMING AT H85.
WED...SINCE THE SHRTWV/SFC LO AND ACCOMPANYING DYNAMICS ARE FCST TO
MOVE STEADILY EWD...EXPECT THE HIER POPS TO SHIFT W-E THRU THE CWA.
THERE IS AN INDICATION THAT WITH AFTN DRYING/RETURN OF SOME
SUNSHINE...THERE WL BE ENUF DESTABILIZATION TO RESULT IN SOME
SHRA/TS OVER THE INTERIOR W HALF. BUT FCST LARGER SCALE QVECTOR DVGC
IN THE WAKE OF THE DISTURBANCE THAT SHARPENS THE MID LVL INVRN
SHOULD LIMIT THIS CHC. WL RETAIN NO HIER THAN SCHC-CHC POPS OVER THE
INTERIOR FOLLOWING THE DEPARTURE OF THE DEEPER MSTR GIVEN FCST KINX
BLO 20 ON NAM FCST SDNGS.
WED NGT...HI PRES BLDG INTO AREA UNDER DNVA IN THE WAKE OF THE
DEPARTING SHRTWV WL BRING DRY WX TO THE CWA. ALTHOUGH THERE COULD BE
SOME LK CLDS IN THE ABSENCE OF DAYTIME HEATING WITH H85 TEMPS
SINKING AS LO AS -6C...DRYNESS OF THE INCOMING AIRMASS AND LLVL ACYC
FLOW SUGS THIS POTENTIAL IS LO.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 443 AM EDT TUE APR 17 2012
AFTER PASSAGE OF SHORTWAVE TROUGH...UPPER AIR PATTERN FOR THURSDAY
FEATURES INCREASING CONFLUENT FLOW EARLY ON. PRIMARY RESULT IS SFC
RIDGE OVR CNTRL CANADA BUILDING INTO UPPER LAKES REGION THROUGH THE
DAY AS SFC FRONTAL BOUNDARY SETTLES INTO CNTRL GREAT LAKES TO
NORTHERN FRINGE OF OHIO VALLEY. BY THURSDAY AFTN...H85 BAROCLINIC
ZONE FCST TO BE MORE FM NORTHERN IOWA INTO CNTRL LOWER MICHIGAN.
NEXT SHORTWAVE TROUGH ALREADY EMERGING ONTO THE PLAINS BY DAYBREAK
THURSDAY WILL BE QUICKLY HEADING INTO WESTERN GREAT LAKES BY AFTN.
MODELS REMAIN AT ODDS ON HOW FAR NORTH TO BRING SFC-H85 LOW PRESSURE
BY LATE THURSDAY AFTN. OPERATIONAL GFS AND GFS ENSEMBLES KEEP THE
LOW TIED TO SFC FRONT THAT WILL BE OVER SOUTHERN PORTIONS OF GREAT
LAKES AND INTO NORTHERN OHIO VALLEY. GFS HAS SHOWED A MORE SOUTHERN
SUPPRESSED SOLUTION FOR THIS SYSTEM QUITE SOME TIME NOW. OTHER
EXTREME IS ECMWF AND ASSOCIATED ENSEMBLES WHICH RIDE SFC LOW
MORE ALONG H85 THERMAL GRADIENT OVR WI AND LOWER MI. THUS...ECMWF
INSISTS THAT MAJORITY OF CWA EXCEPT FOR PERHAPS FAR NW WOULD BE
IMPACTED BY PRECIPITATION. NAM/UKMET AND THE CANADIAN REPRESENT
MIDDLE GROUND CLIPPING SOUTHERN AND EASTERN CWA WITH PRECIPITATION
BUT OTHERWISE KEEPING CWA DRY.
IT IS BECOMING APPARENT THAT A BIG KEY FOR THIS SYSTEM IS EXTENT OF
DRY AIR THAT LURKS AHEAD OF THE SYSTEM AS LATE AS THURSDAY AFTN.
FCST SOUNDINGS FM GFS/ECMWF AND NAM SHOW POCKET OF DRY AIR LINGERING
BTWN H9 AND H7. NAM IS QUITE EMPHATIC WITH THE DRY AIR SHOWING H85
AT 18Z THURSDAY AOB -20C OVR MUCH OF THE CWA BEFORE ERODING THIS
SOMEWHAT BY 00Z FRIDAY. DRY AIR FLOWING IN ON NORTHEAST SFC WINDS FM
LARGE HIGH PRESSURE OVR NORTHERN ONTARIO AND FACT THAT RIBBON OF
SHARP FRONTOGENEIS IS FCST OVR UPR LAKES SUPPORTS IDEA THAT THERE
COULD BE VERY SHARP CUTOFF TO NORTHERN EXTENT OF PRECIPITATION.
INTERESTING THAT EVEN THE ECMWF SHOWS H85 FGEN AXIS JUST SOUTH OF
CWA WITH H7 FGEN AXIS ROUGHLY FM IMT TO SSM ON THURSDAY NIGHT.
IMAGINE MOST OF THE PRECIPITATION FM THE SYSTEM WILL OCCUR ON THE
SOUTHERN EDGE OF THE H7 FGEN...SO THAT WOULD LEAVE FAR SOUTHEAST CWA
IN LINE TO SEE MOST PRECIPITATION WITH THE SYSTEM. MAJORITY OF THE
PRECIP WOULD PROBABLY FALL THURSDAY NIGHT AS THE LEADOFF FORCING ON
THURSDAY WILL ONLY SERVE TO MOISTEN THE VERY DRY LOW-LEVELS. PREV
FCST MATCHES UP WITH THIS THINKING WELL KEEPING HIGHEST POPS NEAR LK
MICHIGAN ON THURSDAY NIGHT. THIS ALSO MATCHES SURROUNDING WFOS VERY
NICELY.
NOW ON TO PTYPE. LOOKS LIKE SNOW FOR MUCH OF THE EVENT. NORTHEAST
SFC WINDS PROBABLY MITIGATE WARMING EFFECT OFF LK MICHIGAN FOR ALL
BUT SOUTHERN MNM COUNTY. ALSO LARGER SCALE FORCING/INTENSE
PRECIPITATION RATES MOST LIKELY WILL OVERWHELM A MINIMAL NEAR SFC
WARM LAYER. 1000-850MB THICKNESSES AND H85 TEMPS FM ECMWF SUPPORT
MAINLY SNOW BY LATER EVENING INTO THE OVERNIGHT HOURS. WWD GRAPHICS
FM HPC INDICATE SEVERAL INCHES OF SNOW POSSIBLE OVR SOUTH AND EAST
CWA ONCE THE RAIN CHANGES TO SNOW. EVEN THOUGH THIS COULD OCCUR IN
NON-GFS SOLUTIONS...REALLY TOUGH TO GO WITH MORE THAN CHANCY POPS
WITH DOWNPLAYED QPF/SNOW AT THIS POINT GIVEN PERSISTENT GFS SOUTHERN
SOLUTION AND FACT THAT SHARP CUTOFF COULD ULTIMATELY PUSH MOST OF
THE PRECIPITATION TO THE SOUTH OF CWA. SYSTEM IS CURRENTLY CHURNING
ACROSS EASTERN PACIFIC HEADING FOR WEST COAST. LOOKS PRETTY SHARP
AND WRAPPED UP ALREADY. UNTIL THE SYSTEM GETS BETTER SAMPLED BY ROAB
NETWORK OVR THE CONUS...PROBABLY WILL BE SEEING MODEL SOLUTIONS
SHOWING VARIABILITY WITH TRACK OF THE SYSTEM. IN OTHER WORDS...STAY
TUNED.
VERY QUIET BEYOND EARLY FRIDAY MORNING. BY FRIDAY AFTN...DEEP H85-H7
DRYING EVEN SHOWN BY STRONGER ECMWF...SO SKIES SHOULD BECOME MOSTLY
SUNNY ALL AREAS. HIGH PRESSURE RIDGE FM HUDSON BAY INTO QUEBEC WILL
BE DOMINANT SFC FEATURE THIS WEEKEND. EXPECT MOSTLY CLEAR SKIES WITH
TEMPERATURES STAYING BLO NORMAL NEAR THE LAKES AND POSSIBLY NEAR
NORMAL INLAND TOWARD WI BORDER /NORMAL HIGHS AT WFO MARQUETTE IN UPR
40S/. NIGHTTIME LOWS WILL LIKELY BE BELOW NORMAL WITH SOME NIGHTS IN
THE TEENS POSSIBLE WITH THE HIGH AND DRY AIRMASS OVERHEAD. EXPECT
AFTN HUMIDITY VALUES TO DROP INTO THE 30-35 PCT RANGE THOUGH COULD
EVEN SEE LOWER READINGS WITH DEEPER MIXING. LIGHT WINDS...COOLER
TEMPS...AND RECENT RAINFALL IN SOME AREAS SHOULD KEEP FIRE WX ISSUES
IN CHECK THROUGH THE WEEKEND THOUGH. APPEARS THAT WARMER TEMPS AND
POSSIBLY WINDY CONDITIONS ARE POSSIBLE EARLY TO MID NEXT WEEK...
THOUGH LATEST ECMWF/GFS INDICATE THIS WARM UP WITH BE REPLACED BY
ANOTHER COOL DOWN JUST BEYOND DAY 7.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 724 AM EDT TUE APR 17 2012
WITH THE ARRIVAL OF DRIER AIR ASSOCIATED WITH A HI PRES RIDGE
BUILDING INTO THE UPPER LAKES AND DAYTIME HEATING...EXPECT MVFR CIGS
TO GIVE WAY TO VFR CONDITIONS BY LATE MORNING AT ALL 3 SITES. THEN
VFR CONDITIONS AND RELATIVELY LIGHT WINDS WILL PREVAIL THRU THIS
EVNG BEFORE AN INCRSG S WIND AHEAD OF AN APPROACHING LO PRES SYSTEM
CAUSES SOME LLWS OVERNGT. AS THE LO CLOSES IN...CLDS WL THICKEN...
BUT CONDITIONS SHOULD REMAIN VFR THRU 12Z EXPECT PERHAPS AT IWD...
WHICH WL BE CLOSER TO THE INCOMING LO.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 AM EDT TUE APR 17 2012
EXPECT LIGHT WINDS INTO TONIGHT WITH HI PRES RIDGE BUILDING INTO THE
AREA. AS A LO PRES SYSTEM APPROACHES TONIGHT AND THE PRES GRADIENT
SHARPENS OVER THE LAKE...S WINDS WILL INCREASE TO AROUND 30 KTS OVER
THE E HALF WED MORNING. IN THE WAKE OF THIS LO PUSHING TO THE E LATE
WED/WED NIGHT...PLAN ON A WSHFT TO THE W WITH WINDS UP TO 25-30 KTS.
THESE STRONGER WINDS WILL DIMINISH AGAIN ON WED NIGHT AS ANOTHER HI
PRES RIDGE BUILDS TOWARD THE UPPER LAKES. DEPENDING ON HOW FAR NORTH
A LOW PRESSURE SYSTEM MOVES...NE WINDS COULD INCREASE TO 25 KTS OVER
SOUTHEAST LAKE SUPERIOR. HI PRES BUILDING INTO THE GREAT LAKES WILL
BRING LIGHTER WINDS FOR THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1025 AM EDT TUE APR 17 2012
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL REMAIN IN CONTROL EARLY TODAY. A COLD
FRONT WILL DROP SOUTHEAST TO AND ACROSS THE LATE TODAY THROUGH
WEDNESDAY... INCREASING THE CHANCES OF SHOWERS AND THUNDERSTORMS.
THIS FRONT WILL STALL JUST OFFSHORE THURSDAY AND THEN DISSIPATE
FRIDAY. A STRONGER COLD FRONT IS EXPECTED SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM TUESDAY...A VERY SLOW MOVING COLD FRONT WHICH IS
CURRENTLY LOCATED FROM THE OUTER BANKS TO THE MIDLAND OF SOUTH
CAROLINA WILL BE THE FOCUS OF TODAYS WEATHER. THIS FRONTAL
BOUNDARY WILL SLOWLY SHIFT ACROSS THE REGION THROUGH TONIGHT.
STILL LOTS OF DRY AIR AROUND WITH THE HIGH PRESSURE AREA ALOFT.
THE 12Z NAM AND 11 UTC HRRR ARE SHOWING WIDELY SCATTED CONVECTION
STARTING BETWEEN 19 AN 20 UTC ALONG THE FRONTAL BOUNDARY FROM
HOLLY RIDGE NORTH CAROLINA TO LUMBERTON TO SOME ISOLATED
CONVECTION SOUTH THE FRONT OVER THE SOUTH CAROLINA COUNTIES.
AS MENTION EARLIER...LOTS OF PROBLEMS FOR DETERMINING THE COVERAGE
OF CONVECTION ALONG THE FRONT. BEST LIFTING WILL REMAIN TO THE WEST...
STILL FAIRLY DRY ALOFT UNTIL THIS AFTERNOON. THE 12 UTC NAM IS
SHOWING A THIN LAYER OF MOISTURE AROUND 5000 TO 8000 THOUSAND
FEET...BUT IT IS NOT DEEP. THE BEST SURFACE BASED CAPES OF 1000
TO 1300 J/KG ARE SEEN RUNNING JUST AHEAD OF THE BOUNDARY FROM DARE
COUNTY DOWN THE COAST OF SOUTHEAST NORTH CAROLINA AND OVER INTO
SOUTH CAROLINA JUST SOUTH OF CHARLOTTE. SO IF THIS INITIALIZATION
IS CORRECT THEM WE COULD EXPECT WIDELY SCATTERED TO SLOWLY SCATTERED
CONVECTION ALONG THIS BOUNDARY.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM TUESDAY...COLD FRONT WILL BE STALLED NEAR THE SOUTHERN
BORDER OF THE CWA EARLY WEDNESDAY. IN THE MID LEVELS A WEAKENING
SHORTWAVE TROUGH WILL BE APPROACHING FROM THE WEST. THIS WILL LEAD
TO A SENSE OF LOW LEVEL WARM ADVECTION THAT WILL SPREAD WEST TO EAST
ACROSS THE REGION. WARMTH AND MOISTURE WILL THEN OVERRUN THE SURFACE
WEDGE OF COOL AIR IN PLACE. THE UPPER TROUGHINESS AND WAA WILL DRAW
THE SURFACE FRONT BACK UP TO PARALLEL THE COASTLINE WHILE IT REMAINS
OFFSHORE WEDNESDAY NIGHT INTO THURSDAY. THE SURFACE WEDGE WILL ALSO
WEAKEN CUTTING DOWN ON THE STRENGTH OF THE SENSE OF ISENTROPIC
UPGLIDE MAKING RAIN CHANCES GO DOWN AS THE DAY WEARS ON. BY THURSDAY
NIGHT BOTH FEATURES WILL HAVE WEAKENED SUFFICIENTLY THAT RAINFALL
CAN BE TAKEN OUT OF THE FORECAST.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...WEAK FLOW/SUBTLE MID LEVEL RIDGING AND POORLY
DEFINED SURFACE GRADIENT IN PLACE EARLY FRIDAY. BY AFTERNOON THE
FORMER MOVES OFF THE COAST AND A FEW SHORTWAVES MAY MOVE THROUGH THE
FLOW CALLING FOR SOME LOW POPS. TEMPERATURES WILL RUN A FEW DEGREES
ABOVE CLIMO. MEANWHILE A SHARPENING UPPER TROUGH WILL BE DEVELOPING
TO OUR WEST. THIS WILL MAKE FOR A VERY UNSETTLED WEEKEND AS THE
TROUGH SHARPENS FURTHER ON SATURDAY AND LOW PRESSURE DEVELOPS ALONG
THE EASTBOUND COLD FRONT. WETTEST OF THE WEATHER LOOKS LIKE SATURDAY
AFTERNOON AS WIDESPREAD SHOWERS AND THUNDERSTORMS SEEM LIKELY. UPPER
TROUGH MAY TILT TO THE NEGATIVE AND LOW LEVEL JET LOOKS STRONG SO
ORGANIZED SEVERE WEATHER LOOKS POSSIBLE. WRAPAROUND MOISTURE AND
IMPRESSIVE COLD ADVECTION SHOULD BE ON TAP FOR SUNDAY. GIVEN THE
LARGE AMPLITUDE AND DISTANT TIME FRAME MODEL SOLUTIONS VARY
CONSIDERABLY. THE GFS LOOKS TOO FAR SOUTH AND CUTS OFF TOO
AGGRESSIVELY TO ARRIVE AT A SOLUTION THAT APPEARS QUITE
CLIMATOLOGICALLY UNLIKELY. THE EC HAS BEEN QUITE CONSISTENT AND
LOOKS MORE POSSIBLE FROM A CLIMO STANDPOINT AND IS WELL SUPPORTED BY
THE CANADIAN SOLUTION. THESE MODELS HAVE BEEN SHOWING A VERY STORMY
EAST COAST SCENARIO AND VERY STRONG COLD ADVECTION INTO THE
SOUTHEAST EARLY NEXT WEEK.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z...THERE IS HIGH CONFIDENCE OF VFR THIS MORNING INTO THE
MID-AFTERNOON HOURS. CONFIDENCE OF VFR LOWERS AFTER THAT TIME AS
SHOWERS AND THUNDERSTORMS DEVELOP ALONG A PRE-FRONTAL TROUGH LBT TO
FLO...AND ON THE SEA BREEZE BOUNDARY. THERE SHOULD BE LITTLE CHANCE
OF OCCURRENCE AT ANY ONE TERMINAL AS CONVECTION WILL BE
ISOLATED...AND ACTIVITY FORMING ON THE SEA BREEZE SHOULD OCCUR WHEN
IT IS LOCATED INLAND FROM THE COAST BUT NOT AS FAR INLAND AS FLO/LBT.
BUT BY EVENING CONVECTIVE COVERAGE IS EXPECTED TO INCREASE AS A COLD
FRONT APPROACHES...WITH THE BEST CHANCES OF OCCURRENCE AT THE FLO
LBT AND ILM TERMINALS. CONVECTION DECREASES AFTER 06Z BUT
SHOWERS/-RA WILL REMAIN LIKELY THOUGH THE END OF THE TAF VALID
PERIOD AS THE COLD FRONT DROPS TO NEAR THE CRE/MYR TERMINALS BY
SUNRISE.
WEST SOUTHWEST TO WEST WINDS WILL BECOME LIGHT NORTHERLY LATER THIS
MORNING AT LBT BEHIND THE PRE-FRONTAL TROUGH...AND MAY CAUSE WINDS
TO BE JUST BE LIGHT AND VARIABLE AT FLO/LBT ALL DAY. WINDS WILL
BECOME SOUTH AT THE CRE/MYR TERMINALS BY LATE MORNING AND AT THE ILM
TERMINALS EARLY AFTERNOON AS THE SEA BREEZE MOVES INLAND.
POST-FRONTAL BR DEVELOPMENT WILL BECOME MORE LIKELY AFTER MIDNIGHT
AS COOLER AIR FILTERS IN BEHIND THE COLD FRONT...WITH VISIBILITIES
DROPPING TO AT LEAST MVFR. THINK THE CHANCE OF IFR WILL BE LOW DUE
TO CLOUD COVER.
EXTENDED OUTLOOK...POSSIBLE TEMPO REDUCED FLIGHT CONDITIONS DUE TO
SCATTERED SHOWERS AND THUNDERSTORMS EACH DAY...WITH THE BEST CHANCE
FRIDAY INTO SATURDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM TUESDAY...SOUTHWEST WINDS OF 10 KNOTS ARE BLOWING
OVER THE WATERS AND SEAS ARE GENERALLY AROUND 2 FEET. SO NO
CHANGES ARE PLANNED. PREVIOUS DISCUSSION FOLLOWS...
HIGH PRESSURE OFF THE SOUTHEAST U.S. COAST WILL WEAKEN LATER TODAY
AS A COLD FRONT DROPS SOUTH THROUGH VIRGINIA AND NORTH
CAROLINA...REACHING THE COASTAL WATERS NEAR CAPE FEAR AROUND SUNSET.
SOUTHWEST WINDS OUT AHEAD OF THE FRONT WILL TURN EASTERLY NEAR AND
NORTH OF CAPE FEAR THIS EVENING...THEN NORTHEASTERLY TONIGHT AS HIGH
PRESSURE CENTERED OVER THE EASTERN GREAT LAKES TRIES TO BUILD SOUTH.
THE FRONT WON`T MAKE TREMENDOUS PROGRESS SOUTHWARD HOWEVER...AND THE
SOUTH CAROLINA COASTAL WATERS WILL PROBABLY NOT SEE THIS FRONT MOVE
THROUGH TONIGHT. SOUTHWESTERLY WINDS HERE THIS MORNING WILL BACK TO
SOUTHERLY WITH THE SEABREEZE THIS AFTERNOON AND REMAIN SOUTHERLY
TONIGHT. WAVE MODELS SHOW NO SIGNIFICANT SWELL TO AFFECT THE
AREA...AND SHORT PERIOD WIND WAVES SHOULD AVERAGE 2-3 FT THROUGH
TONIGHT.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...COLD FRONT WILL BE IN THE AREA FOR MUCH OF THE
PERIOD. ITS EXACT POSITION WILL BE RATHER UNCERTAIN FOR A GOOD PART
OF THE PERIOD MAKING THE EXACT DIRECTION OF THE WIND FORECAST IN
NEED OF POSSIBLE REFINEMENT. HOWEVER AS USUAL WITH A FRONT NEARBY
WIND SPEED WILL BE QUITE LOW. THE BOUNDARY WILL BE OFF TO THE SOUTH
EARLY WEDNESDAY BRINGING ON ONSHORE AND NORTHERLY WIND. AS THE FRONT
DRAWS CLOSER TO THE COAST WED NIGHT INTO THURSDAY THERE COULD BE A
SLIGHT DECREASE IN THE FLOW. SEAS WILL BE IN THE 2 TO 3 FT RANGE
MOST OF THE SHORT TERM. THE ONSHORE COMPONENT WILL ACT TO DIMINISH
THE NEARSHORE/OFFSHORE WAVE HEIGHT GRADIENT.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...A SOUTHERLY FLOW WILL BECOME RE-ESTABLISHED
EARLY IN THE PERIOD AS HIGH PRESSURE CONSOLIDATES OFF THE MID
ATLANTIC COAST. A STRONG COLD FRONT WILL BE APPROACHING FROM THE
WEST HOWEVER AND THIS WILL EVENTUALLY LEAD TO A DRAMATIC INCREASE IN
BOTH WIND AND WAVES. THERE IS SOME UNCERTAINTY REGARDING THE SPEED
OF THIS BOUNDARY (BUT MOST OF THE FORECAST UNCERTAINTY INVOLVES THE
POST-FRONTAL REGIME BEYOND THE VALID TIME OF THE LONG TERM). CURRENT
FORECAST WILL SHOW A RAMP UP TO WHERE SCEC HEADLINES WILL BE NEEDED
BUT IN LIGHT OF THE ANTICIPATED FURTHER DETERIORATION SMALL CRAFT
ADVISORIES APPEAR MUCH MORE LIKELY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DRH
SHORT TERM...III
LONG TERM...BACON
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
703 AM CDT TUE APR 17 2012
.DISCUSSION...LOW PRESSURE OVER FAR SOUTHWEST SASKATCHEWAN WILL
MOVE EAST SOUTHEAST INTO FAR WESTERN NORTH DAKOTA AROUND 18 UTC
TODAY. WARM SOUTHERLY FLOW AHEAD OF THE LOW HAS WARMED
TEMPERATURES ACROSS THE WEST ABOVE FORECAST VALUES. READINGS ARE
GENERALLY AROUND 40 DEGREES ACROSS THE FAR WEST. FARTHER
EAST...TEMPERATURES REMAIN IN THE MID 20S TO LOWER 30S BUT EXPECT
TEMPERATURES HERE TO BEGIN TO RISE QUICKLY AS MID AND HIGH LEVEL
CLOUDS ENCOMPASS THE REGION AND SURFACE FLOW INCREASES FROM THE
SOUTH. MADE SOME MINOR ADJUSTMENTS TO SKY COVER AND ALSO
TEMPERATURES TO ACCOUNT FOR CURRENT WARMER TEMPERATURES WEST.
LATEST SHORT TERM MODELS ARE KEEPING THE MAJORITY OF THE
PRECIPITATION THIS MORNING CONFINED TO THE NORTHERN TIER COUNTIES
OF WESTERN NORTH DAKOTA. 07 UTC HRRR IS FARTHER SOUTH WITH
REFLECTIVITIES BUT THIS IS OVERDONE WHEN COMPARING TO CURRENT
RADAR TRENDS. THUS WE DROPPED POPS DOWN TO SLIGHT CHANCE OVER THE
SOUTHWEST THIS MORNING.
&&
.AVIATION......MID AND HIGH LEVEL CLOUDINESS IS INCREASING ACROSS
THE WESTERN AND CENTRAL NORTH DAKOTA. SOUTHERLY SURFACE FLOW IS
OCCURRING OVER THE AREA WITH SURFACE HIGH PRESSURE MOVING EAST OF
THE JAMES RIVER VALLEY. A LOW PRESSURE SYSTEM CURRENTLY OVER
SOUTHWEST SASKATCHEWAN WILL MOVE QUICKLY SOUTHEAST INTO CENTRAL
NORTH DAKOTA BY THIS AFTERNOON...AND INTO MINNESOTA BY 12 UTC
THURSDAY. THIS WILL BRING A CHANCE OF SHOWERS AND POSSIBLY
AFTERNOON/EARLY EVENING THUNDERSTORMS TO THE AREA. THE LEADING
EDGE OF PRECIPITATION IS ABOUT TO PUSH INTO THE FAR NORTHWEST.
VFR CEILINGS ARE EXPECTED TODAY AHEAD OF THE SURFACE LOW. AS THE
LOW TRACKS EAST TONIGHT...WRAP AROUND MOISTURE AND SCATTERED MVFR
CEILINGS ARE POSSIBLE. SOUTHERLY FLOW AHEAD OF THE LOW WILL SHIFT
NORTHWEST TO NORTH BEHIND THE SYSTEM.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...TWH
LONG TERM....TWH
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS DENVER CO
302 PM MDT TUE APR 17 2012
.SHORT TERM...WEAK SHORTWAVE FINALLY SLIDING ACROSS WYOMING WITH
TAIL END MOVING OVER NORTHWEST COLORADO. RADAR SHOWING SOME
PRECIPITATION DEVELOPING OVER THE NORTHERN MOUNTAINS THOUGH WEB
CAMS SHOWING MOST OF THIS ACTIVITY ALONG CONTINENTAL DIVIDE IN
GRAND COUNTY. SHOULD BEGIN TO SEE THE PRECIP BECOMING A BIT MORE
WIDESPREAD AS MID LEVEL QG ASCENT INCREASES. MODELS SHOW BEST LIFT
TO STAY WELL NORTH OF COLORADO AS WAVE MOVES ACROSS REGION. RUC
AND NAM CROSS SECTIONS SHOW SOME INCREASE IN MOISTURE...MAINLY
ABOVE MOUNTAIN TOP. LATEST RUC AND HRRR AS WELL AS THE 18Z NAM
RUN DO NOT GENERATE MUCH IN THE WAY OF QPF THROUGH THE EVENING.
WILL MAINTAIN THE SCATTERED POPS FOR MOST OF MOUNTAIN AREAS NORTH
OF INTERSTATE 70 THROUGH EARLY EVENING...WITH DECREASING POPS
REST OF THE EVENING. AS FOR THUNDER CHANCES...FORECAST CAPES STILL
LOOKING LOW...MAYBE 300 J/KG FOR A SHORT TIME OVER THE NORTHERN
MOUNTAINS. SO FAR...NO LIGHTNING NOTED UPSTREAM. WILL NOT INCLUDE
FOR EVENING FORECASTS. TEMPERATURES TO BE COLD ENOUGH FOR SNOW
ACROSS THE MOUNTAINS WITH MAINLY RAIN VALLEY AREAS. ACROSS
PLAINS...STILL A SLIGHT CHANCE FOR A FEW HIGH BASED SHOWERS ALONG
THE WYOMING BORDER EARLY THIS EVENING WITH REST OF THE PLAINS DRY.
WINDS TO INCREASE FOR A SHORT TIME BEHIND THE EXITING WAVE BEFORE
DECREASING DURING THE EVENING. GRADUAL CLEARING EXPECTED OVERNIGHT
WHICH SHOULD KEEP TEMPERATURES FAIRLY MILD. ON WEDNESDAY...NEXT
TROUGH APPROACHES FROM THE NORTHWEST AS MODERATE WESTERLY FLOW
ALOFT CONTINUES OVER COLORADO. MODEL CROSS SECTIONS SHOW SOME
INCREASE IN MOISTURE ACROSS MOUNTAINS DURING THE AFTERNOON ALONG
WITH SOME WEAK QG ASCENT. BEST AREA FOR ANY PRECIPITATION LOOKS TO
BE THE NORTHERN MOUNTAINS SO WILL WILL INCREASE THE POPS THERE TO
THE CHANCE CATEGORY FOR THE AFTERNOON. THICKNESS PROGS SUGGEST
A SLIGHT CHANCE OF SNOW. FORECAST CAPES REMAIN LOW SO WILL NOT
MENTION THUNDER. AS FOR PLAINS...SOME SHOWERS POSSIBLE FOR AREAS
NEAR THE WYOMING BORDER IN AREA OF BETTER ASCENT. MODELS GENERATE
SOME CAPE ALONG THE BORDER...STILL LOOK A BIT LOW TO MENTION
THUNDER AT THIS TIME. THE SHOWERS THAT DO DEVELOP SHOULD BE HIGH
BASED AND CAPABLE OF PRODUCING BRIEF GUSTY WINDS. WILL LEAVE REST
OF PLAINS DRY. SOUTHERLY WINDS TO INCREASE AHEAD OF TROUGH...
THOUGH MODELS SHOW WINDS MORE WESTERLY ACROSS PLAINS WITH PASSAGE
OF WEAK FRONT. THIS MAY BE A BIT FAST GIVEN TO SLOW MOVEMENT OF
UPPER TROUGH. TEMPERATURE AND THICKNESS PROGS AS WELL AS GUIDANCE
SHOW HIGHS IN THE LOWER AND MIDDLE 70S ACROSS PLAINS. CURRENT
TEMPERATURE GRIDS IN LINE WITH GUIDANCE...LOOKS REASONABLE.
.LONG TERM...THE NEXT UPPER LEVEL TROF WILL MOVE ACROSS COLORADO
ON LATE WEDNESDAY AND THURSDAY AND GRADUALLY DEEPEN AS IT MOVES
INTO THE CENTRAL PLAINS. THE MODELS ARE VARIED ON MOISTURE
AVAILABILITY WITH THE GFS THE WETTER OF THE MODELS AND MORE
UPSLOPE WHILE THE NAM LOOKS LIKE DRIER WITH THE MOST DOWNSLOPE
FLOW. GIVEN THE VARIABILITY WILL LEAVE THE POPS MAINLY IN THE
SLIGHT CHANCE OVER LOWER ELEVATIONS BUT A SLIGHT BUMP UPWARDS. THE
MOUNTAINS WILL PROBABLY HAVE A BRIEF PERIOD OF RAIN/SNOW SHOWERS
ON THURSDAY AND THROUGH THE NIGHT WITH LIGHT NW OROGRAPHIC FLOW.
THE QG FIELDS ARE ONLY SHOWING WEAK ASCENT SO AT THIS POINT NOT
ALL THAT EXCITED ABOUT THIS NEXT DISTURBANCE.
HIGH PRESSURE RIDGE ALOFT WILL BUILD OVER THE ENTIRE REGION FROM
FRIDAY THROUGH EARLY NEXT WEEK WITH DRYING AND WARMING TREND
THROUGH THE PERIOD. MODELS ARE SHOWING A BIT OF MOISTURE
DEVELOPING UNDER THE RIDGE BY EARLY NEXT WEEK BUT NOT WORTH ADDING
ANY POPS AT THIS TIME.
&&
.AVIATION...TROUGH STILL WEST OF THE DENVER AREA...WITH VARIABLE
WINDS AT AREA AIRPORTS. THROUGH EXPECTED TO MOVE ACROSS THE AREA
EARLY EVENING. SHOULD SEE WINDS SHIFT TO THE NORTHWEST BY 23Z WITH
SPEEDS AROUND 15 KTS. SOME INCREASE IN MID LEVEL CLOUDS BUT NOW
DOES NOT APPEAR THAT ILS CEILINGS WILL DEVELOP. WILL MAINTAIN THE
LATEST UPDATE TRENDS FOR THE 00Z ISSUANCE. ANY SHOWERS THAT
DEVELOP WILL STAY NORTH AND WEST OF DENVER AIRPORTS. WINDS TO
DECREASE AND BECOME SOUTHERLY DURING THE EVENING AS DRAINAGE FLOW
DEVELOPS. THE SOUTHERLY WINDS TO CONTINUE THROUGH THE DAY...MAY
BECOME A BIT MORE SOUTHEAST DURING THE AFTERNOON. SOME HIGH BASED
SHOWERS POSSIBLE NORTH OF THE AREA AFTER 18Z...NOT EXPECTED TO
AFFECT THE AREA AIRPORTS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....ENTREKIN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
403 PM EDT TUE APR 17 2012
.SYNOPSIS...
A COLD FRONT WILL REMAIN POSITIONED WEST OF THE REGION OVERNIGHT.
THE FRONT WILL MOVE SLOWLY ACROSS THE REGION WEDNESDAY AFTERNOON AND
WEDNESDAY NIGHT BEFORE STALLING OVER OR JUST EAST OF THE AREA INTO
FRIDAY. A STRONG LOW PRESSURE SYSTEM WILL THEN AFFECT THE REGION
THIS WEEKEND FOLLOWED BY COOLER HIGH PRESSURE EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THIS AFTERNOON...THE EXPANSIVE CU FIELD CONTINUES ACROSS THE
FORECAST AREA WITH THE SEA BREEZE BEGINNING TO PUSH INLAND. SO FAR
THE SUBSIDENCE INVERSION AND CAP NOTICED ON MODEL SOUNDINGS IS
HOLDING AND NO SHOWERS OR STORMS HAVE STARTED DEVELOPING ACROSS THE
REGION. WATER VAPOR IMAGERY AND RUC DATA SHOW THE OFFSHORE RIDGE
HOLDING STRONG...AND RECENT RUNS OF THE HRRR SHOW VIRTUALLY NO
COVERAGE THROUGH THE EVENING HOURS.
TONIGHT...THE UPSTREAM SHORTWAVE WILL BEGIN TO MAKE SOME EASTWARD
PROGRESS AND GRADUALLY ERODE THE UPPER RIDGE. THROUGH SUNRISE IT
LOOKS AS THOUGH THE MAIN VORT ENERGY WILL REMAIN JUST WEST OF THE
FORECAST AREA. THE COLD FRONT WILL MAKE LITTLE PROGRESS OVERNIGHT AS
A WEAK SURFACE WAVE DEVELOPS OVER SOUTH AL/GA AND BEGINS TO RIDE TO
THE NE. THIS WILL PLACE THE FORECAST AREA IN BETWEEN THE WEAK
SURFACE LOW AND THE WESTERN ATLANTIC HIGH...WHICH WILL SUPPORT LIGHT
BUT PERSISTENT S TO SW FLOW. OVERALL SKIES WILL BE CLEAR TO MOSTLY
CLEAR FOR MUCH OF THE NIGHT...WITH SOME MAINLY HIGH LEVEL CLOUDINESS
MOVING IN FROM THE WEST. THERE ARE SOME INDICATIONS THAT AREAS OF
STRATOCU COULD DEVELOP AND ADVECT INLAND OVERNIGHT...BUT MODELS
DON/T SHOW A TREMENDOUS AMOUNT OF MOISTURE IN THE LOWEST 5K FT OF
THE ATMOSPHERE. THERE MAY ALSO BE SOME SHALLOW GROUND FOG IN THE FEW
HOURS RIGHT AROUND SUNRISE...BUT WE SHOULD MAINTAIN ENOUGH FLOW TO
PREVENT FOG FROM MUCH DEEPER OR WIDESPREAD. I HAVE TAPERED POPS BACK
TO KEEP MOST OF THE OVERNIGHT DRY...WITH JUST A SMALL AREA OF SLIGHT
CHANCE TO CHANCE ACROSS THE WEST AROUND SUNRISE. LOW TEMPS SHOULD BE
PRETTY SIMILAR TO LAST NIGHT...WITH LOW 60S TO NEAR 60 JUST ABOUT
EVERYWHERE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
AN UPPER SHORTWAVE TROUGH OF LOW PRESSURE WILL SHIFT THROUGH THE
AREA WEDNESDAY INTO WEDNESDAY NIGHT ALONG WITH A SURFACE COLD
FRONT AND WEAK AREA OF LOW PRESSURE. THE FRONT WILL THEN LIKELY
STALL OUT JUST OFFSHORE INTO FRIDAY AS HIGH PRESSURE SLIDES BY TO
THE NORTH. RAIN CHANCES LOOK TO INCREASE FROM THE WEST WEDNESDAY
THROUGH WEDNESDAY NIGHT WITH DEEPER MOISTURE MOVING THROUGH ALONG
WITH THE UPPER TROUGH AND SURFACE LOW/FRONT. INSTABILITY APPEARS
TO BE LIMITED ALTHOUGH 30-35 KT BULK SHEAR COULD LEAD TO A FEW
STRONGER STORMS. SOME SHOWERS AND THUNDERSTORMS EXPECTED THURSDAY
WITH THE LINGERING SURFACE BOUNDARY NEARBY...THE AFTERNOON SEA
BREEZE AND ADDITIONAL WEAK SHORTWAVE ENERGY ALOFT. RAIN CHANCES
LIKELY EVEN A BIT LESS ON FRIDAY GIVEN A BIT LESS MOISTURE AND
SLIGHT WARMING ALOFT. TEMPERATURES GENERALLY AT OR SLIGHTLY ABOVE
NORMAL...ESPECIALLY LOWS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A LARGE AND POTENTIALLY STRONG LOW PRESSURE SYSTEM WILL AFFECT THE
SOUTHEAST THIS WEEKEND. AT THIS TIME...MODELS ARE STRUGGLING WITH
THE TIMING AND TRACK OF THE LOW PRESSURE SYSTEM AS IT PASSES OVER
THE SOUTHEAST. LATEST GUIDANCE DOES FAVOR A MORE SOUTHERN TRACK OF A
DEEP LOW THROUGH THE SOUTHERN GULF STATES BEFORE SHIFTING OFF THE
SOUTHEAST ATLANTIC COAST. THIS TRACK ALONG WITH STRONG MID/UPPER LVL
DYNAMICS AND MODEST INSTABILITY IN THE WARM SECTOR WOULD FAVOR
STRONG THUNDERSTORMS OVER OR NEAR THE FORECAST AREA SOMETIME LATE
SATURDAY THROUGH SUNDAY EVENING. A COOLING/DRYING TREND IS THEN
ANTICIPATED ONCE FROPA OCCURS OVER THE WEEKEND. TEMPS WILL RANGE
FROM THE UPPER 70S/LOWER 80S SATURDAY AND POSSIBLY SUNDAY BEFORE
RETURNING TO NEAR OR BELOW NORMAL LEVELS MONDAY AND TUESDAY.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE TAF PERIOD. NO
CONCERNS IN THE FIRST 12 HOURS OF THE FORECAST...AFTER WHICH THERE
IS A SMALL CHANCE OF STRATOCU ADVECTING INLAND LATE TONIGHT. NONE
OF THE MODEL GUIDANCE IS HITTING THIS POTENTIAL VERY HARD SO I
HAVE LEFT THINGS VFR AND HAVE ONLY GONE WITH FEW MVFR CLOUDS. AS
THE WEAK SURFACE LOW DEVELOPS TO THE WEST...THE AREA WILL BE
CAUGHT BETWEEN THIS FEATURE AND THE PERSISTENT HIGH OVER THE
ATLANTIC. THIS SHOULD GENERATE ENOUGH FLOW TO KEEP FOG DEVELOPMENT
AS GROUND FOG AT BEST DESPITE CLEAR TO PARTLY CLOUDY SKIES. CLOUDS WILL
BEGIN INCREASING WEDNESDAY MORNING BUT IT APPEARS ANY PRECIP WILL
BE CONFINED TO THE AFTERNOON/EVENING HOURS.
EXTENDED AVIATION OUTLOOK...MVFR/IFR CIGS/VSBYS LIKELY AT BOTH
TERMINALS WED NIGHT AS SHOWERS/TSTMS AFFECT THE AREA AS A WEAK COLD
FRONT PUSHES OFFSHORE. ADDITIONAL MVFR/POSSIBLY WORSE CIGS/VSBYS
LATE THU NIGHT. BREEZY/GUSTY CONDITIONS LIKELY SAT WITH INCREASING
CHANCES FOR SUB-VFR CONDS THROUGH THE WEEKEND AS A STRONG LOW
PRESSURE SYSTEM APPROACHES THE AREA FROM THE W.
&&
.MARINE...
TONIGHT...THE LOCAL WATERS WILL BE CAUGHT IN AN AREA BETWEEN A
DEVELOPING WEAK LOW PRESSURE TO THE WEST AND HIGH PRESSURE JUST TO
THE EAST. THIS WILL HELP MAINTAIN A MODERATE S TO SW FLOW OF
GENERALLY 10 TO 15 KTS THROUGH THE NIGHT. SEAS WILL ALSO BE WELL
BELOW SCA CRITERIA...GENERALLY 2-3 FT WITH MOST OF THAT BEING
COMPRISED OF 1-2 FT SWELL EVERY 7-8 SECONDS.
WEDNESDAY THROUGH SUNDAY...A WEAK COLD FRONT WILL SHIFT OVER THE
COASTAL WATERS LATE WEDNESDAY INTO EARLY THURSDAY BEFORE STALLING
OUT OVER OR JUST E OF THE WATERS INTO FRIDAY. NO SIGNIFICANT MARINE
CONCERNS THROUGH FRI NIGHT...HOWEVER CONDITIONS WILL BEGIN TO GO
DOWNHILL LATER SATURDAY INTO SUNDAY AS A STRONG LOW PRESSURE SYSTEM
APPROACHES FROM THE WEST. SMALL CRAFT ADVISORIES ARE LIKELY SATURDAY
NIGHT FOR WINDS AND SEAS...AT LEAST BEYOND 20 NM...WITH THE
NEARSHORE WATERS LIKELY REACHING ADVISORY LEVELS SUNDAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...BSH
SHORT TERM...RJB
LONG TERM...RJB
AVIATION...BSH/RJB
MARINE...BSH/RJB
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1200 PM CDT TUE APR 17 2012
...UPDATE TO AVIATION FOR 18Z TAFS...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 346 AM CDT TUE APR 17 2012
PATCHY DENSE FOG HAS DEVELOPED OUT ALONG AND WEST OF A LINE FROM SCOTT
CITY AND GARDEN CITY DOWN TOWARD MEADE. MSAS/RUC ANALYSIS IS SHOWING
A SWATH OF LOW DEWPOINT DEPRESSION LINING UP WELL WITH THE FOG. SO FAR
THE FOG HAS REMAINED FAIRLY PATCHY AS INDICATED ON THE 11-3.9 MICRON
SATELLITE CHANNEL. MODEL SOUNDINGS SHOW MOISTURE TO BE VERY SHALLOW
AND THE SURFACE VISIBILITY FORECAST FROM THE HRRR IS TRENDING AWAY
FROM DEVELOPING WIDESPREAD LOW VISIBILITIES THIS MORNING. CURRENT
THINKING IS TO HANDLE THE FOG WITH A MENTION OF PATCHY DENSE IN
THE GRIDS AND NOWCAST IT THROUGH SUNRISE. IF DENSE FOG BECOMES
MORE WIDESPREAD MAY NEED TO ISSUE AN ADVISORY. THE FOG SHOULD BE
FAIRLY QUICK TO BURN OFF TODAY AS LOW LEVEL MIXING ENSUES AND
SOUTH TO SOUTHWEST WINDS INCREASE.
SHORTWAVE RIDGING OVER THE CENTRAL HIGH PLAINS EARLY THIS MORNING WILL
MOVE EAST TODAY WITH ZONAL FLOW SPREADING EASTWARD FROM THE ROCKIES
TODAY AND TONIGHT. GOOD MIXING TODAY WILL RESULT IN TEMPERATURES
CLIMBING INTO THE 70S...WITH UPPER 70S IN THE WEST. THE DEEP MIXING
SHOULD PUSH RELATIVE HUMIDITY LEVELS DOWN INTO THE UPPER TEENS OVER
FAR SOUTHWEST KANSAS. THE LOW RH`S SHOULD BE ATTENUATED SOMEWHAT
BY THE ONGOING GREENUP AND INCREASED EVAPOTRANSPIRATION SO ANY
SIGNIFICANT FIRE WEATHER ISSUES ARE NOT ANTICIPATED.
SOME SCATTERED CIRRUS WILL PASS OVER WESTERN KANSAS TONIGHT AS THE
AFOREMENTIONED SHORTWAVE MOVES EAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 400 AM CDT TUE APR 17 2012
MEDIUM RANGE MODELS INDICATE A ZONAL FLOW ALOFT PERSISTING ACROSS
THE WESTERN HIGH PLAINS TO BEGIN THE PERIOD WEDNESDAY. MEANWHILE, AN
UPPER LEVEL SHORTWAVE TROUGH WILL TRANSITION EAST FROM THE NORTHERN
PLAINS INTO THE GREAT LAKES REGION. A FAIRLY WEAK ATTENDANT COLD
FRONT IS EXPECTED TO PUSH JUST INTO NORTHWESTERN KANSAS BEFORE
STALLING OUT, POSSIBLY JUST INTO NORTHERN PORTIONS OF SOUTHWEST
KANSAS AND PORTIONS OF CENTRAL KANSAS JUST SOUTH OF THE I-70
CORRIDOR. HOWEVER, NO SIGNIFICANT PRECIPITATION IS EXPECTED WITH
THIS FRONT WITH A GENERALLY WEAK FLOW ALOFT. HOWEVER, THE CHANCES
FOR PRECIP DO PICK UP A LITTLE THURSDAY AS ANOTHER UPPER LEVEL
SHORTWAVE IS PROGGED TO SWING ACROSS THE WESTERN PLAINS. AN
ATTENDANT COLD FRONT TO THIS SYSTEM WILL PUSH SOUTHEAST WELL INTO
AND ACROSS WESTERN KANSAS DURING THE DAY THURSDAY BRINGING THE
CHANCE FOR SHOWERS AND A FEW THUNDERSTORMS TO PORTIONS OF WESTERN
KANSAS BY THURSDAY EVENING. HOWEVER, HOW STRONG ANY POSSIBLE STORMS
MAY BE REMAINS UNCERTAIN. NAM AND GFS MODEL SOUNDINGS HINT AT A
POSSIBLE LACK OF LOW LEVEL MOISTURE ALONG WITH LESS THAN FAVORABLE
INSTABILITY LEVELS. ADDITIONALLY, TIMING OF THE FRONT COULD BE AN
ISSUE AS WELL WITH ALL MODELS PROJECTING THE FRONTAL PASSAGE TO TAKE
PLACE EARLIER IN THE DAY. LOW END CHANCE CATEGORY POPS SEEM
REASONABLE AT THIS POINT. DRIER CONDITIONS ARE THEN EXPECTED
THROUGH THE WEEKEND AND INTO THE EARLY PART OF NEXT WEEK AS UPPER
LEVEL RIDGING DEVELOPS AND PUSHES EAST ACROSS THE INTERMOUNTAIN
WEST.
TEMPERATURES ARE EXPECTED TO BE JUST ABOVE NORMAL WEDNESDAY AS A
ZONAL FLOW PERSISTS ACROSS THE WESTERN HIGH PLAINS. A LEE SIDE
TROUGH OF LOW PRESSURE IS EXPECTED TO REDEVELOP ACROSS EASTERN
COLORADO RETURNING A LOW LEVEL SOUTHERLY FLOW TO SOUTHWESTERN AND
SOUTH CENTRAL KANSAS BY LATE AFTERNOON. THE NAM, GFS, AND ECMWF SHOW
H85 TEMPERATURES IN THE MID TO UPPER TEENS(C) ACROSS CENTRAL KANSAS
TO THE LOWER 20S(C) ACROSS SOUTHWESTERN KANSAS. WITH LOWER LEVEL DRY
LAPSE RATES LIKELY BY WEDNESDAY AFTERNOON, LOOK FOR HIGHS UP INTO
THE UPPER 70S(F) TO THE LOWER TO MID 80S(F). A GENERAL COOLING TREND
IS LIKELY THROUGH THE END OF THE WEEK AS MUCH COOLER AIR SURGES
SOUTH INTO WESTERN KANSAS IN WAKE OF THE COLD FRONTAL PASSAGE
THURSDAY. HIGHS COULD STRUGGLE TO REACH THE 70S(F) THURSDAY
DEPENDING ON ANY CLOUD COVER ASSOCIATED WITH THE COLD FRONT
AND THE TIMING OF THE PASSAGE ITSELF.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1200 PM CDT TUE APR 17 2012
VFR CIGS EXPECTED THROUGH THE ENTIRE TAF PERIOD. SOME CIRRUS IS
POSSIBLE THROUGH THE PERIOD AS AN UPPER LEVEL SHORTWAVE TROUGH MOVES
THROUGH. NEXT CONCERN IS WIND SHIFTS...A WEAK COLD FRONT/FRAGMENTING
LEE SURFACE TROUGH AXIS WILL MOVE THROUGH DURING THE MORNING HOURS.
BREEZY 15-20 KT SW WINDS THIS AFTERNOON WILL GRADUALLY VEER BY MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 76 49 81 53 / 0 10 0 0
GCK 74 46 81 50 / 0 0 0 0
EHA 76 47 83 51 / 0 0 0 0
LBL 77 48 84 53 / 0 10 0 0
HYS 73 49 78 52 / 0 10 0 0
P28 73 53 81 55 / 0 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GERARD
LONG TERM...JJOHNSON
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
333 PM EDT TUE APR 17 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR A DRY FORECAST FOR THE MAJORITY OF
THE AREA THROUGH FRIDAY. THE EXCEPTION WILL BE THE CHANCE OF
SHOWERS AS A WEAK LOW PRESSURE SYSTEM PASSES SOUTHEAST OF THE AREA
ON WEDNESDAY. A COLD FRONT APPROACHING FROM THE WEST WILL RETURN
THE CHANCE OF SHOWERS AND THUNDERSTORMS LATE FRIDAY AND INTO THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY IN A
SOUTHWESTERLY FLOW AHEAD OF A BROAD AND WEAK SHORT WAVE TROUGH
ACROSS THE GREAT LAKES. AT THE SURFACE, HIGH PRESSURE IS CENTERED
ACROSS LAKE MICHIGAN AND EXTENDS ACROSS THE OHIO VALLEY. MID TO
UPPER LEVEL MOISTURE CONTINUES TO FILTER IN FROM THE SOUTHWEST,
ALLOWING FOR MOSTLY CLOUDY SKIES.
THE MID-LEVEL FLOW WILL FLATTEN AND BECOME MORE ZONAL THROUGH
TONIGHT, WITH HIGH PRESSURE SLIDING ACROSS THE GREAT LAKES. THE LOBE
OF HIGH PRESSURE IS PROGGED TO BE CENTERED ACROSS LAKE ONTARIO BY
12Z WEDNESDAY. 500-250MB LAYER MOISTURE SHOULD PROVIDE ENOUGH CLOUD
COVERAGE TO LIMIT RADIATIONAL COOLING. LOWS TONIGHT ARE CLOSER TO
THE WARMER MAV GUIDANCE, RANGING FROM THE MID 30S ALONG THE I-80
CORRIDOR TO THE MID 40S ACROSS NORTH-CENTRAL WV. THE I-80 CORRIDOR
IS CURRENTLY MARGINALLY WARMER THAN FREEZING FOR LOWS, SO WILL NOT
ISSUE A FREEZE WARNING AT THIS TIME.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
THERE IS GFS/ECMWF/NAM AGREEMENT THAT A SHORT WAVE WILL PASS
SOUTHEAST OF THE AREA WITH A WEAK SURFACE LOW ON WEDNESDAY. TO THE
NORTHWEST, A SURFACE LOW WILL MOVE INTO THE NORTHERN GREAT LAKES,
PUSHING A WARM FRONT NORTHWARD INTO THE REGION. AT THIS TIME, IT
APPEARS THAT THE UPPER OHIO VALLEY WILL STAY MOSTLY DRY IN BETWEEN
THESE FEATURES ON WEDNESDAY. THERE IS STILL A LITTLE UNCERTAINTY AS
TO WHETHER PRECIP ON THE NORTHERN EDGE OF THE SHORT WAVE CAN MAKE IT
INTO THE SOUTHEASTERN RIDGES WEDNESDAY AFTERNOON, SO HAVE LEFT A
SCHC THERE. WITH ABUNDANT SUNSHINE ANTICIPATED AS A DEEP LAYER OF
DRY AIR CROSSES THE AREA, TEMPS ARE FORECAST TO RECOVER NICELY AFTER
THE COLD START. HIGHS ARE FORECAST TO BE AROUND 5 DEGREES ABOVE
SEASONAL NORMALS.
GFS/ECMWF REMAIN IN AGREEMENT WEDNESDAY NIGHT THROUGH FRIDAY
AFTERNOON. THE NAM IS CONSIDERED TO BE AN OUTLIER, BRINGING PRECIP IN
EARLIER IN THE DAY. THE FORECAST LEANS TO THE SLOWER ECMWF/GFS
SOLUTIONS, KEEPING THE FORECAST DRY MOST OF THE DAY FRIDAY AHEAD
OF A COLD FRONT APPROACHING FROM THE WEST. WITH THE WARM FRONT
NORTH OF THE AREA, TEMPERATURES WILL BECOME PROGRESSIVELY WARMER
THURSDAY INTO FRIDAY, WARMING TO 10 TO 15 DEGREES ABOVE NORMAL FOR
HIGHS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A COLD FRONT WILL SLOWLY ADVANCE EASTWARD ACROSS THE REGION FRIDAY
NIGHT THROUGH SATURDAY NIGHT. FORECAST A SWATH OF LIKELY POPS FOR
SHOWERS TO SHIFT SOUTHEASTWARD ACROSS THE FORECAST AREA ON
SATURDAY...WITH PRECIPITATION TAPERING TO SCATTERED COVERAGE DURING
SATURDAY NIGHT.
MODELS SHOW A CLOSED UPPER LOW FORMING AT THE BOTTOM OF A SHARP
TROUGH AND RIDING EAST ALONG THE GULF COAST SATURDAY AND SUNDAY.
LATEST MODEL RUNS STILL DIFFER ON THE TRACK OF A SURFACE LOW MOVING
ALONG THE EASTERN SEABOARD AND THE WESTERN EXTENT OF PRECIPITATION
MONDAY AND TUESDAY. FORECAST POPS ARE CLOSE TO HPC NUMBERS WITH HIGH
END CHANCE POPS SUNDAY TAPERING TO AROUND 30 PERCENT ALONG THE
RIDGES AND SLIGHT CHANCE FURTHER WEST BY MONDAY MORNING.
TEMPERATURES ARE FORECAST TO COOL TO BETWEEN 5 AND 10 DEGREES BELOW
NORMAL BY EARLY NEXT WEEK.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
SURFACE HIGH PRESSURE WILL DRIFT EAST ACROSS THE GREAT LAKES REGION
THROUGH WEDNESDAY. VFR CONDITIONS AND LIGHT WINDS ARE FORECAST
THROUGH THE TAF PERIOD...WITH AREAS OF MIDDLE AND HIGH CLOUDS MOVING
ACROSS THE UPPER OHIO VALLEY.
OUTLOOK...WEDNESDAY NIGHT THROUGH SUNDAY...
VFR WEATHER SHOULD PREVAIL INTO FRIDAY UNDER A WEAK RIDGE.
RESTRICTIONS WILL BE LIKELY IN SHOWERS LATE FRIDAY NIGHT THROUGH
SUNDAY AS A FRONTAL BOUNDARY SLOWLY CROSSES THE OHIO VALLEY AND A
SURFACE LOW TRACKS FROM THE GULF COAST TO ALONG THE CAROLINA
COAST.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
209 PM EDT TUE APR 17 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR A DRY FORECAST FOR THE MAJORITY OF
THE AREA THROUGH FRIDAY. THE EXCEPTION WILL BE THE CHANCE OF
SHOWERS AS A WEAK LOW PRESSURE SYSTEM PASSES SOUTHEAST OF THE AREA
ON WEDNESDAY. A COLD FRONT APPROACHING FROM THE WEST WILL RETURN
THE CHANCE OF SHOWERS AND THUNDERSTORMS LATE FRIDAY AND INTO THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO
INCREASE THE CLOUD COVERAGE THIS AFTERNOON AND OVERNIGHT.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A SOUTHWESTERLY FLOW WITH A BROAD AND WEAK TROUGH ACROSS THE
GREAT LAKES. AT THE SURFACE, HIGH PRESSURE IS CENTERED ACROSS LAKE
MICHIGAN AND EXTENDS ACROSS THE OHIO VALLEY. MID TO UPPER LEVEL
MOISTURE IS FILTERING IN FROM THE SOUTHWEST, ALLOWING FOR CLOUD
COVERAGE TO INCREASE TO MOSTLY CLOUDY.
MOISTURE ALOFT WILL CONTINUE TO FILTER IN FROM THE SOUTHWEST AND ALLOW
FOR MOSTLY CLOUDY SKIES. TEMPS TODAY ARE NEAR LAMP GUIDANCE, WITH
HIGHS RANGING FROM THE UPPER 50S ACROSS THE EASTERN RIDGES TO THE
MID 60S SOUTHWEST OF PITTSBURGH.
MID-LEVEL FLOW WILL FLATTEN AND BECOME MORE ZONAL THROUGH
TONIGHT, WITH HIGH PRESSURE SLIDING ACROSS THE GREAT LAKES. THE
LOBE OF HIGH PRESSURE IS PROGGED TO BE CENTERED ACROSS LAKE
ONTARIO BY 12Z WEDNESDAY. 500-250MB LAYER MOISTURE SHOULD PROVIDE
ENOUGH CLOUD COVERAGE TO LIMIT RADIATIONAL COOLING. LOWS TONIGHT
ARE CLOSER TO THE WARMER MAV GUIDANCE, RANGING FROM THE MID 30S
ALONG THE I-80 CORRIDOR TO THE MID 40S ACROSS NORTH-CENTRAL WV.
THE I-80 CORRIDOR IS CURRENTLY MARGINALLY WARMER THAN FREEZING FOR
LOWS, SO WILL NOT ISSUE A FREEZE WARNING AT THIS TIME.
&&
.SHORT TERM /WEDNESDAY/...
RECENT SREF MODEL OUTPUT SHOWS SURFACE HIGH PRESSURE, COMING EAST
FROM IOWA, CONTINUING DRY CONDITIONS FOR MOST OF THE UPPER OHIO
VALLEY THROUGH WEDNESDAY.
A COUPLE SREF MEMBERS SHOW LOW PRESSURE MOVING NORTHEASTWARD THROUGH
THE MID-ATLANTIC STATES AND PERHAPS SPREAD ISOLATED LIGHT SHOWERS
ACROSS THE WV-MD MOUNTAINS DAYTIME WEDNESDAY.
TEMPERATURES SHOULD CONTINUE TO REMAIN CLOSE TO NORMAL VALUES BASED
OFF OF THE MOST RECENT MAV/MEX GUIDANCE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
RECENT SREF MODEL OUTPUT SHOWS EASTBOUND LOW PRESSURE THROUGH THE
GREAT LAKES PERHAPS LAYING A STALLED COLD FRONT ACROSS NORTHERN
PENNSYLVANIA THURSDAY. EXPECT LITTLE SHOWER DEVELOPMENT BUT AN
INCREASE IN CLOUDS THURSDAY INTO FRIDAY.
BLEND OF RECENT ECMWF, GFS, AND CMC, SHOW A BETTER DEVELOPED LOW
PRESSURE SYSTEM, COMING EAST FROM THE NORTHERN ROCKIES, WILL PROVIDE
THE UPPER OHIO VALLEY WITH SHOWERS AND POSSIBLE THUNDERSTORMS LATE
FRIDAY INTO SUNDAY.
GFS MOS AND NAEFS MEDIAN VALUES SHOW WARMER THAN NORMAL TEMPERATURES
INTO SATURDAY, FOLLOWED BY A POST-SYSTEM COOL DOWN TO SEASONABLE
TEMPERATURES SUNDAY AND MONDAY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
EXPECT VFR TO CONTINUE THROUGH TONIGHT, WITH LITTLE MORE THAN
PASSING STRANDS OF ALTOCUMULUS AND CIRRUS.
SURFACE WINDS WILL REMAIN NORTHWESTERLY 8 TO 15 KTS INTO EVENING,
THEN DECREASE TO 5 KTS.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
VFR INTO FRIDAY. RESTRICTIONS LIKELY FRIDAY NIGHT AND SATURDAY FROM
PREFRONTAL SHOWERS AND POSSIBLE THUNDERSTORMS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
114 PM EDT TUE APR 17 2012
.SYNOPSIS...
ISSUED AT 443 AM EDT TUE APR 17 2012
00Z RAOBS/LATEST WV IMAGERY AND LATEST RUC ANALYSIS SHOW SHRTWV
RESPONSIBLE FOR WINTRY MIX/GUSTY WINDS YDAY SHEARING ENEWD OVER
ONTARIO ON NW FLANK OF SHARP UPR RDG OFF THE SE COAST. ALTHOUGH
ASSOCIATED SFC LO IS WEAKENING AND MOVING QUICKLY TO THE E THRU
QUEBEC...SOME SHSN ARE FALLING OVER THE NCNTRL AND E AS OF MIDNGT
UNDER THE WEAKENING BUT LINGERING CYC NW FLOW LEFT IN ITS WAKE.
00Z H85 TEMPS AS LO AS -11C PER RUC ANALYSIS AND CONSIDERABLE
LLVL MSTR/INVRN BASE ARND H85 SHOWN ON THE 00Z APX RAOB ARE
CONDITIONS CONDUCIVE FOR THIS BIT OF LATE SEASON LES AND EXTENSIVE
LK SC. UNDER THE H85 THERMAL TROF...SFC TEMPS ARE QUITE CHILLY WITH
TEMPS GENERALLY IN THE 20S. ALTHOUGH PTCHY LO CLDS ARE STILL PRESENT
AS FAR W AS THE MN ARROWHEAD...ANY LINGERING PCPN IS ENDING OVER THE
W WITH APRCH OF TRAILING HI PRES RDG AND VERY DRY AIR SHOWN ON THE
00Z INL RAOB /PWAT 0.13 INCH/. LOOKING FARTHER W...AN UPPER RDG IS
BLDG INTO THE PLAINS WITH 12Z-24Z H3 RISES ARND 150M OVER THE NRN
PLAINS AND S OF NRN BRANCH TROF OVER CENTRAL CANADA. 00Z BISMARCK
RAOB DOES SHOW SOME MSTR THAT SUPPORTED A GOOD AMOUNT OF SC IN THE
NRN PLAINS YDAY. ANOTHER SHRTWV IS MOVING ONSHORE IN THE PAC NW.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 443 AM EDT TUE APR 17 2012
MAIN FCST CONCERNS DURING THIS TIME ARE PCPN TRENDS EARLY THIS
MRNG...TEMPS TODAY...AND THEN PCPN CHCS LATE TNGT THRU WED
ASSOCIATED WITH SHRTWV NOW MOVING THRU THE PAC NW.
EARLY THIS MRNG...AS SHRTWV/SFC LO TO THE E CONTINUE TO SLIDE AWAY
AND HI PRES BUILDS INTO THE WRN CWA BY 09Z UNDER STEADY H5
RISES/DNVA THAT IS FCST TO LOWER INVRN BASE TO UNDER 3K FT AT ERY BY
09Z. SO ALTHOUGH QUITE A BIT OF SC WILL LINGER...EXPECT ANY -SHSN TO
BE OVER BY 12Z. LINGERING SC OVER MUCH OF THE CWA WL LIMIT
ADDITIONAL DIURNAL TEMP DROP.
TODAY...WITH HI PRES/DRY AIRMASS PUSHING E ACROSS THE CWA...EXPECT
LAKE EFFECT SC IN THE MRNG TO DISSIPATE IN THE PRESENCE OF DAYTIME
HEATING AND WEAKENING CYC FLOW. BUT WITH HINT OF LINGERING H85
THERMAL TROF AND ARRIVAL OF SOME MSTR SHOWN ON THE 00Z BISMARCK
RAOB...MORE DIURNAL CU/SC SHOULD DVLP OVER MAINLY THE W HALF
INTERIOR INLAND AWAY FM LK BREEZES THAT FORM IN THE RELATIVELY WEAK
PRES GRADIENT. MIXING TO H85-8 ON NAM FCST SDNGS YIELD HI TEMPS
RANGING FM ARND 40 AT ERY TO THE UPR 40S NEAR THE WI BORDER. WITH LK
BREEZE FORMATION...EXPECT COOLER READINGS NEAR THE LK SHORES.
TNGT...LATEST NUMERICAL MODELS IN GOOD AGREEMENT SHOWING SHRTWV NOW
IN THE PAC NW/ACCOMPANYING SFC LO MOVING THRU THE NRN PLAINS AND
INTO NE MN BY 12Z WED...WITH WAD PCPN IN ADVANCE OF THIS FEATURE
OVERSPREADING THE W HALF OF UPR MI BY SUNRISE. MAIN FORCING
MECHANISMS LOOK TO BE VIGOROUS UPR DVGC IN LEFT EXIT OF SUPPORTING
H3 JET MAX/VIGOROUS ISENTROPIC ASCENT POWERED BY H85 SW 50-60KT
WINDS/VIGOROUS H85-7 FGEN IN ADVANCE OF ATTENDANT WARM FNT. OPTED TO
BUMP POPS UP TO CATEGORICAL OVER THE W AFT 06Z GIVEN THESE POTENT
DYNAMICS/IMPRESSIVE DEEP LYR QVECTOR CNVGC/MODEL CONSISTENCY ON
GENERATING PCPN IN THIS AREA. ALTHOUGH FCST H100-85 THKNS AS HI AS
1320-1335M IN ADVANCE OF PCPN ARRIVAL...RAPID ARRIVAL OF WAD
CLD...FASTER ADVECTION OF HIER LLVL SPECIFIC HUMIDITY THAN EARLIER
FCSTS INDICATED...ONSET OF STRONGER WINDS INDICATE PCPN SHOULD BE
ALL RA...INITIAL RELATIVE DRYNESS OF LLVLS THAT LOWERS WBLB TO BLO
32 AT THE SFC SUPPORTS MAINTAING A MENTION OF A BIT OF -FZRA AT THE
ONSET OF THE RA SHIELD OVER THE INTERIOR. ANY ICING WOULD BE
INSIGNIFICANT DUE TO STEADY WARMING SOON AFT PCPN ARRIVAL. UTILIZED
A NON-DIURNAL TEMP CURVE TO HANDLE TEMP TRENDS. TEMPS WL BE LOWEST
AND SINK BLO 32 OVER THE E...BUT PCPN WL NOT GET THERE BEFORE
SUNRISE. ALTHOUGH GFS/NAM SHOW LAPSE RATES NOT MUCH STEEPER THAN
MOIST ADIABATIC/ MUCAPE UNDER 50 J/KG...RETAINED MENTION OF SCHC TS
GIVEN VIGOROUS DYNAMICS/STRONG WARMING AT H85.
WED...SINCE THE SHRTWV/SFC LO AND ACCOMPANYING DYNAMICS ARE FCST TO
MOVE STEADILY EWD...EXPECT THE HIER POPS TO SHIFT W-E THRU THE CWA.
THERE IS AN INDICATION THAT WITH AFTN DRYING/RETURN OF SOME
SUNSHINE...THERE WL BE ENUF DESTABILIZATION TO RESULT IN SOME
SHRA/TS OVER THE INTERIOR W HALF. BUT FCST LARGER SCALE QVECTOR DVGC
IN THE WAKE OF THE DISTURBANCE THAT SHARPENS THE MID LVL INVRN
SHOULD LIMIT THIS CHC. WL RETAIN NO HIER THAN SCHC-CHC POPS OVER THE
INTERIOR FOLLOWING THE DEPARTURE OF THE DEEPER MSTR GIVEN FCST KINX
BLO 20 ON NAM FCST SDNGS.
WED NGT...HI PRES BLDG INTO AREA UNDER DNVA IN THE WAKE OF THE
DEPARTING SHRTWV WL BRING DRY WX TO THE CWA. ALTHOUGH THERE COULD BE
SOME LK CLDS IN THE ABSENCE OF DAYTIME HEATING WITH H85 TEMPS
SINKING AS LO AS -6C...DRYNESS OF THE INCOMING AIRMASS AND LLVL ACYC
FLOW SUGS THIS POTENTIAL IS LO.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 443 AM EDT TUE APR 17 2012
AFTER PASSAGE OF SHORTWAVE TROUGH...UPPER AIR PATTERN FOR THURSDAY
FEATURES INCREASING CONFLUENT FLOW EARLY ON. PRIMARY RESULT IS SFC
RIDGE OVR CNTRL CANADA BUILDING INTO UPPER LAKES REGION THROUGH THE
DAY AS SFC FRONTAL BOUNDARY SETTLES INTO CNTRL GREAT LAKES TO
NORTHERN FRINGE OF OHIO VALLEY. BY THURSDAY AFTN...H85 BAROCLINIC
ZONE FCST TO BE MORE FM NORTHERN IOWA INTO CNTRL LOWER MICHIGAN.
NEXT SHORTWAVE TROUGH ALREADY EMERGING ONTO THE PLAINS BY DAYBREAK
THURSDAY WILL BE QUICKLY HEADING INTO WESTERN GREAT LAKES BY AFTN.
MODELS REMAIN AT ODDS ON HOW FAR NORTH TO BRING SFC-H85 LOW PRESSURE
BY LATE THURSDAY AFTN. OPERATIONAL GFS AND GFS ENSEMBLES KEEP THE
LOW TIED TO SFC FRONT THAT WILL BE OVER SOUTHERN PORTIONS OF GREAT
LAKES AND INTO NORTHERN OHIO VALLEY. GFS HAS SHOWED A MORE SOUTHERN
SUPPRESSED SOLUTION FOR THIS SYSTEM QUITE SOME TIME NOW. OTHER
EXTREME IS ECMWF AND ASSOCIATED ENSEMBLES WHICH RIDE SFC LOW
MORE ALONG H85 THERMAL GRADIENT OVR WI AND LOWER MI. THUS...ECMWF
INSISTS THAT MAJORITY OF CWA EXCEPT FOR PERHAPS FAR NW WOULD BE
IMPACTED BY PRECIPITATION. NAM/UKMET AND THE CANADIAN REPRESENT
MIDDLE GROUND CLIPPING SOUTHERN AND EASTERN CWA WITH PRECIPITATION
BUT OTHERWISE KEEPING CWA DRY.
IT IS BECOMING APPARENT THAT A BIG KEY FOR THIS SYSTEM IS EXTENT OF
DRY AIR THAT LURKS AHEAD OF THE SYSTEM AS LATE AS THURSDAY AFTN.
FCST SOUNDINGS FM GFS/ECMWF AND NAM SHOW POCKET OF DRY AIR LINGERING
BTWN H9 AND H7. NAM IS QUITE EMPHATIC WITH THE DRY AIR SHOWING H85
AT 18Z THURSDAY AOB -20C OVR MUCH OF THE CWA BEFORE ERODING THIS
SOMEWHAT BY 00Z FRIDAY. DRY AIR FLOWING IN ON NORTHEAST SFC WINDS FM
LARGE HIGH PRESSURE OVR NORTHERN ONTARIO AND FACT THAT RIBBON OF
SHARP FRONTOGENEIS IS FCST OVR UPR LAKES SUPPORTS IDEA THAT THERE
COULD BE VERY SHARP CUTOFF TO NORTHERN EXTENT OF PRECIPITATION.
INTERESTING THAT EVEN THE ECMWF SHOWS H85 FGEN AXIS JUST SOUTH OF
CWA WITH H7 FGEN AXIS ROUGHLY FM IMT TO SSM ON THURSDAY NIGHT.
IMAGINE MOST OF THE PRECIPITATION FM THE SYSTEM WILL OCCUR ON THE
SOUTHERN EDGE OF THE H7 FGEN...SO THAT WOULD LEAVE FAR SOUTHEAST CWA
IN LINE TO SEE MOST PRECIPITATION WITH THE SYSTEM. MAJORITY OF THE
PRECIP WOULD PROBABLY FALL THURSDAY NIGHT AS THE LEADOFF FORCING ON
THURSDAY WILL ONLY SERVE TO MOISTEN THE VERY DRY LOW-LEVELS. PREV
FCST MATCHES UP WITH THIS THINKING WELL KEEPING HIGHEST POPS NEAR LK
MICHIGAN ON THURSDAY NIGHT. THIS ALSO MATCHES SURROUNDING WFOS VERY
NICELY.
NOW ON TO PTYPE. LOOKS LIKE SNOW FOR MUCH OF THE EVENT. NORTHEAST
SFC WINDS PROBABLY MITIGATE WARMING EFFECT OFF LK MICHIGAN FOR ALL
BUT SOUTHERN MNM COUNTY. ALSO LARGER SCALE FORCING/INTENSE
PRECIPITATION RATES MOST LIKELY WILL OVERWHELM A MINIMAL NEAR SFC
WARM LAYER. 1000-850MB THICKNESSES AND H85 TEMPS FM ECMWF SUPPORT
MAINLY SNOW BY LATER EVENING INTO THE OVERNIGHT HOURS. WWD GRAPHICS
FM HPC INDICATE SEVERAL INCHES OF SNOW POSSIBLE OVR SOUTH AND EAST
CWA ONCE THE RAIN CHANGES TO SNOW. EVEN THOUGH THIS COULD OCCUR IN
NON-GFS SOLUTIONS...REALLY TOUGH TO GO WITH MORE THAN CHANCY POPS
WITH DOWNPLAYED QPF/SNOW AT THIS POINT GIVEN PERSISTENT GFS SOUTHERN
SOLUTION AND FACT THAT SHARP CUTOFF COULD ULTIMATELY PUSH MOST OF
THE PRECIPITATION TO THE SOUTH OF CWA. SYSTEM IS CURRENTLY CHURNING
ACROSS EASTERN PACIFIC HEADING FOR WEST COAST. LOOKS PRETTY SHARP
AND WRAPPED UP ALREADY. UNTIL THE SYSTEM GETS BETTER SAMPLED BY ROAB
NETWORK OVR THE CONUS...PROBABLY WILL BE SEEING MODEL SOLUTIONS
SHOWING VARIABILITY WITH TRACK OF THE SYSTEM. IN OTHER WORDS...STAY
TUNED.
VERY QUIET BEYOND EARLY FRIDAY MORNING. BY FRIDAY AFTN...DEEP H85-H7
DRYING EVEN SHOWN BY STRONGER ECMWF...SO SKIES SHOULD BECOME MOSTLY
SUNNY ALL AREAS. HIGH PRESSURE RIDGE FM HUDSON BAY INTO QUEBEC WILL
BE DOMINANT SFC FEATURE THIS WEEKEND. EXPECT MOSTLY CLEAR SKIES WITH
TEMPERATURES STAYING BLO NORMAL NEAR THE LAKES AND POSSIBLY NEAR
NORMAL INLAND TOWARD WI BORDER /NORMAL HIGHS AT WFO MARQUETTE IN UPR
40S/. NIGHTTIME LOWS WILL LIKELY BE BELOW NORMAL WITH SOME NIGHTS IN
THE TEENS POSSIBLE WITH THE HIGH AND DRY AIRMASS OVERHEAD. EXPECT
AFTN HUMIDITY VALUES TO DROP INTO THE 30-35 PCT RANGE THOUGH COULD
EVEN SEE LOWER READINGS WITH DEEPER MIXING. LIGHT WINDS...COOLER
TEMPS...AND RECENT RAINFALL IN SOME AREAS SHOULD KEEP FIRE WX ISSUES
IN CHECK THROUGH THE WEEKEND THOUGH. APPEARS THAT WARMER TEMPS AND
POSSIBLY WINDY CONDITIONS ARE POSSIBLE EARLY TO MID NEXT WEEK...
THOUGH LATEST ECMWF/GFS INDICATE THIS WARM UP WITH BE REPLACED BY
ANOTHER COOL DOWN JUST BEYOND DAY 7.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 113 PM EDT TUE APR 17 2012
WITH THE ARRIVAL OF DRIER AIR ASSOCIATED WITH A HIGH PRESSURE RIDGE
BUILDING INTO THE UPPER LAKES AND DAYTIME HEATING AND MIXING...VFR
CONDITIONS WILL CONTINUE AT ALL 3 SITES THROUGH LATE EVENING. AN
INCREASING SOUTH WIND AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM
WILL CAUSE SOME LLWS LATE TONIGHT AT ALL SITES. AS THE LOW CLOSES
IN...CLDS WL THICKEN...AND MVFR CIGS AND VIS WILL SET IN WITH RAIN
LATE TONIGHT INTO WED MORNING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 AM EDT TUE APR 17 2012
EXPECT LIGHT WINDS INTO TONIGHT WITH HI PRES RIDGE BUILDING INTO THE
AREA. AS A LO PRES SYSTEM APPROACHES TONIGHT AND THE PRES GRADIENT
SHARPENS OVER THE LAKE...S WINDS WILL INCREASE TO AROUND 30 KTS OVER
THE E HALF WED MORNING. IN THE WAKE OF THIS LO PUSHING TO THE E LATE
WED/WED NIGHT...PLAN ON A WSHFT TO THE W WITH WINDS UP TO 25-30 KTS.
THESE STRONGER WINDS WILL DIMINISH AGAIN ON WED NIGHT AS ANOTHER HI
PRES RIDGE BUILDS TOWARD THE UPPER LAKES. DEPENDING ON HOW FAR NORTH
A LOW PRESSURE SYSTEM MOVES...NE WINDS COULD INCREASE TO 25 KTS OVER
SOUTHEAST LAKE SUPERIOR. HI PRES BUILDING INTO THE GREAT LAKES WILL
BRING LIGHTER WINDS FOR THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLA
AVIATION...07
MARINE...KC
AREA FORECAST DISCUSSION
NWS JACKSON MS
351 PM CDT TUE APR 17 2012
.SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT...LARGE RAIN SHIELD
OVERSPREADING THE REGION AS ABUNDANT MOISTURE IS IN PLACE. BLENDED
TOTAL PRECIPITABLE WATER SATELLITE IMAGERY INDICATES 1-1.5 INCHES
ACROSS MAINLY LOCATIONS ALONG AND SOUTH OF I-20. THIS IS GENERALLY
120-180 PERCENT OF NORMAL. THIS HAS LED TO SEVERAL FLASH FLOOD
WARNINGS ACROSS THE REGION. STORM TOTAL PRECIP SINCE YESTERDAY
MORNING INDICATES THAT MANY LOCATIONS GENERALLY ALONG AND WEST OF
I-55 SHOWS RAINFALL TOTALS AROUND 3-5 INCHES. THIS ACTIVITY COMES AS
A SHORTWAVE TROUGH SLOWLY MOVES INTO THE REGION. WHILE THE PRIMARY
CONCERN IS THE FLOODING ACROSS THE REGION...SOME BETTER CONVECTIVE
CELLS HAVE EXHIBITED SOME STRONG TO SEVERE TENDENCY...ESPECIALLY
THOSE THAT ARE ENTERING A REGION THAT HAS BEEN ABLE TO WARM
UP/DESTABILIZE BETTER TODAY. EXTENSIVE CLOUD COVER AND CONTINUOUS
RAIN HAS KEPT TEMPERATURES IN THE UPPER 50S AND LOWER 60S FOR MUCH
OF THE DAY. THE FAR SOUTHEAST AND EAST HAVE BEEN ABLE TO WARM MORE
WITH LATER ONSET OF CLOUD COVER AND RAIN. THESE LOCATIONS HAVE
GOTTEN INTO THE MID TO UPPER 60S AND LOWER 70S. IT IS IN THESE AREAS
WHERE RUC ANALYSIS SHOWS SLIGHT BETTER SFC CAPE(CLOSE TO 1000 J/KG).
WHILE LOW LEVEL SHEAR IS ON THE LOW SIDE...DEEPER LAYER SHEAR IS
ABOUT 30-40KTS. THE MAIN CONCERN WITH THESE WOULD BE WIND GUSTS AS
MID LEVEL TEMPS ARE NOT TOO COLD WITH VALUES AROUND -11 TO -13C TO
SUPPORT MUCH HAIL...BUT IF ANY IT WILL BE ON THE SMALL SIDE.
AS THE SHORTWAVE TROUGH CONTINUES TO MOVE ACROSS THE REGION THIS
AFTERNOON AND THIS EVENING...THE AXIS OF RAIN WILL CONTINUE TO SHIFT
TO THE EAST. GRADUAL CLEARING WILL TAKE PLACE FROM WEST TO EAST
THROUGH THE EVENING INTO TONIGHT WITH DRIER AIR FILTERING IN BEHIND
IT ALONG WITH HIGH PRESSURE AT THE SFC. WITH THE CLEARING
SKIES...RELATIVELY LIGHT WINDS AND SATURATED SOILS...PATCHY FOG COULD
DEVELOP TONIGHT AFTER MIDNIGHT. THIS WOULD MAINLY BE FOR LOCATIONS
ALONG AND NORTHWEST OF THE NATCHEZ TRACE. DECENTLY HIGH SREF PROBS
ALSO INDICATE THIS PROBABILITY AND HAVE INCLUDED IN THE FORECAST. BY
12Z WEDNESDAY...MODEL PW VALUES ARE 0.45 INCHES ACROSS THE
DELTA...0.70 INCHES ACROSS THE JACKSON AREA AND JUST UNDER AN INCH IN
THE PINE BELT. THIS WILL ALLOW FOR A RATHER PLEASANT DAY WEDNESDAY.
SUNNY SKIES...A GOOD NORTH WIND AND DRIER AIR WILL BE IN PLACE.
TEMPERATURES WILL START OUT CHILLY IN THE MORNING WITH READINGS IN
THE UPPER 40S IN THE DELTA...TO THE MID/UPPER 50S IN THE PINE
BELT(WHERE CLOUDS AND RAIN WILL BE SLOWER TO DEPART OVERNIGHT).
AFTERNOON HIGHS WILL REACH INTO THE MID 70S WEDNESDAY.
SFC HIGH PRESSURE CENTERED ACROSS THE MID-ATLANTIC STATES CONTINUES
TO BE BETTER ESTABLISHED ACROSS THE AREA THROUGH THURSDAY WITH
GENERALLY ZONAL FLOW ALOFT. THIS WILL LEAD TO DRY
CONDITIONS...MOSTLY SUNNY SKIES...COOL OVERNIGHT LOWS DUE TO GOOD
RADIATIONAL COOLING CONDITIONS AND COOLER AFTERNOON HIGHS. BY THURSDAY
NIGHT...THE SFC HIGH WILL BE SHIFTING FURTHER EAST...BRINGING THE
REGION UNDER THE WESTERN PERIPHERY AND SOUTHERLY WINDS WILL RETURN.
MOISTURE WILL INCREASE AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM
LOCATED ACROSS THE TEXAS PANHANDLE/RED RIVER VALLEY AT 12Z FRIDAY.
WITH THE INCREASE IN MOISTURE...OVERNIGHT LOWS ON THURSDAY WILL BE
HIGHER AND INTO THE LOWER 50S. /28/
.LONG TERM...FRIDAY THROUGH TUESDAY...MAIN FOCUS IN THE MEDIUM RANGE
WILL BE ON A DIGGING SHORTWAVE INTO THE DEEP SOUTH THAT BOTH GFS AND
ECMWF MODELS NOW ARE CLOSING OFF A 500MB(560DM) LOW CENTER NEAR THE MS
COAST FOR SATURDAY NIGHT AND THEN MOVING IT SLOWLY EWD. MEANWHILE...A
FLAT MID LEVEL RIDGE ALOFT SHOULD HOLD A DRY WNW ZONAL FLOW IN PLACE
THURSDAY THAT BACKS WITH WEAK LOW LEVEL WARM ADVECTION DEVELOPING
THURSDAY NIGHT AND FRIDAY. EXPECT LOW LEVEL FRONTOGENESIS FROM THE MID
SOUTH TO THE ARKLATEX FRIDAY NIGHT WITH INCREASING RAIN/TSRA CHANCES
FOR OUR AREA FRIDAY AFTERNOON RIGHT THROUGH SATURDAY EVENING.
THE SLOWER PROGRESSION OF THIS SYSTEM WILL RESULT IN HIGHER QPF
AMOUNTS THAT WOULD NOW APPEAR TO BE AROUND 2 INCHES WITH LOCALLY
HIGHER 3 TO 4 INCHES POSSIBLE IN SERN MS BY EARLY SUNDAY. A WIDER
RIBBON OF 1.4 INCH PWATS AND 7-500MB LAPSE RATES OF 6.5C SUPPORT
SCATTERED TSRA ALONG THE SLOWING FRONT FRIDAY NIGHT WITH SURFACE
CYCLOGENESIS(1003MB) IN THE KMSY VICINITY EARLY SATURDAY. THE FRONT
PLODS EWD INTO THE I-59 CORRIDOR LATER ON SATURDAY WITH AN UPPER
DEFORMATION ZONE LOCKING IN THE WRAP AROUND MOISTURE BEING FORCED
NWWD ON STRENGTHENING ELY LOW LEVEL FLOW THROUGH THE GULF STATES. WE
COULD BE IN FOR A REAL SOAKER AS PATTERN TAKING ON MORE OF AN EL NINO
LOOK LATELY.
WE FINALLY BEGIN DRYING OUT EARLY SUNDAY FOLLOWED BY A NOTICEABLY
COOLER AIRMASS FOR THE START OF NEXT WEEK AS OVERNIGHT LOWS LIKELY TO
DIP INTO THE 40S EARLY SUNDAY AND MONDAY MORNINGS. OUR HIGHS STAY
WELL BELOW NORMAL IN THE 65-72F RANGE SUNDAY BEFORE A WARMING TREND
ARRIVES MONDAY AND TUESDAY. HAVE LEANED TOWARD THE ENSEMBLE MEANS
FOR MAXES OVER THE WEEKEND AS LONGER DAYLIGHT HOURS TEND TO MODERATE
THESE AIR MASSES EFFECTIVELY. 500MB HEIGHT RISES OF 40-60M SUNDAY AND
AGAIN ON MONDAY ALLOW LOW LEVEL WAA TO PUSH DAYTIME READINGS UPWARD
AND THESE SHOULD BE VERY CLOSE TO THE NORMALS FOR THIS TIME IN APRIL
WITH LOWS IN THE BACK INTO THE 50S AND HIGHS 75-80F BY TUESDAY./40/
&&
.AVIATION...WIDESPREAD IFR CONDITIONS ARE ASSOCIATED WITH A LARGE
RAIN/THUNDERSTORM COMPLEX MOVING ACROSS THE FORECAST AREA THIS AFTN.
WE WILL SEE IMPROVING CONDITIONS FROM WEST TO EAST AS WE GO THROUGH
LATE AFTERNOON WITH VFR CONDITIONS DEVELOPING FROM THE EVENING INTO
THE OVERNIGHT HOURS...ESPECIALLY AT GLH/GWO/JAN/HBG. IFR CATEGORY
STRATUS MAY BE GENERATED OVER EASTERN MS (GTR/MEI) IN THE WEAK COLD
ADVECTION PATTERN...AND WITH THE CLEARING SKIES AND DECREASING WIND
FARTHER WEST...AREAS OF FOG MAY DEVELOP AFTER 06Z AND PERSIST DURING
THE MORNING HOURS. ANY FOG/STRATUS WILL MIX OUT BY AROUND 15Z
WEDNESDAY MORNING AND VFR CONDITIONS CAN BE EXPECTED THROUGH
WEDNESDAY AFTERNOON/EVENING. /EC/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 48 75 49 81 / 31 2 0 0
MERIDIAN 52 76 48 81 / 83 7 0 0
VICKSBURG 49 74 48 81 / 11 0 0 0
HATTIESBURG 55 79 52 83 / 71 5 0 0
NATCHEZ 49 73 49 78 / 20 0 0 0
GREENVILLE 49 75 50 80 / 9 0 0 0
GREENWOOD 49 74 49 81 / 19 0 0 0
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
28/40/EC
AREA FORECAST DISCUSSION
NWS GLASGOW MT
1021 AM MDT TUE APR 17 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
UPDATED TO THE FORECAST TO MAKE A FEW MINOR CHANGES. LOOKING AT
FORECAST SOUNDING FROM BUFKIT AND AWIPS BUFR SOUNDING DECIDED TO
GO AHEAD AND LAUNCH A LAKE WIND ADVISORY FROM NOON UNTIL 9 PM THIS
EVENING. NORTHWEST WINDS OF 15 TO 25 MPH ARE LIKELY WITH THE
OCCASIONAL GUST UP TO 30 BEING MIXED TO THE SURFACE. RAISED THE
DAY TIME HIGHS SLIGHTLY SINCE WE ARE SEEING MORE CLEARING WITH
PARTLY CLOUDY SKIES ACROSS NEMONT. SOLAR RADIATION SHOULD BE ABLE
TO PENETRATE WHAT CLOUD COVER THERE IS TO WARM THINGS UP INTO THE
LOWER TO MID 60S THIS AFTERNOON.
ALSO THE 12Z NAM/GFS AND THE LATEST HRRR MODEL RUN INDICATES
POSSIBLE ISOLATED THUNDER WITH THE SCATTERED RAIN SHOWERS THIS
AFTERNOON. MODELS ARE HINTING AT A POSSIBLE .10 OF AN INCH OF QPF
SOUTH OF THE MISSOURI RIVER THIS AFTERNOON AND EVENING. THE
DISAPPOINTMENT IN THE MODELS QPF OUTPUT HAS BEEN SUBSTANTIAL FROM
MYSELF AND OTHER FORECASTER HERE. SO WITH THIS IN MIND DON`T COUNT
ON ANYTHING OVER A FEW HUNDREDTHS OF AN INCH OF PRECIPITATION
SOUTH OF THE MISSOURI RIVER THIS AFTERNOON AND EVENING. RSMITH
PREVIOUS DISCUSSION...SHORTWAVE SYSTEM FROM THE W MOVING INTO THE
AREA TODAY WITH MODELS INDICATING SOME SOME SPLITTING OF MOISTURE
AND UPPER SUPPORT. WARM FRONT SHOWERS THIS MORN WILL BE MAINLY
OVER CANADA AND OUR EXTREME N. A WEAK PACIFIC COLD FRONT WILL
BRING DOWN SLOPE WARMING AND DRYING INTO MUCH OF THE REST OF OUR
AREA...WITH MOISTURE HEADING MOSTLY INTO BYZ CWA. A SECONDARY
CANADIAN COLD FRONT ARRIVES LATE AFTERNOON AND EVE FROM THE NNW.
MORE MODEL VARIATION ON TIMING AND QPF...BUT GENERALLY NOT
EXPECTING MUCH.
MODELS SHOW 850-700 MB LAYER MB LAYER WINDS WILL BE 20-30 KT
EARLY MORNING...BUT DROPPING OFF TO 15-20 KT IN THE AFTERNOON WHEN
WE MIX DRY ADIABATICALLY TO THAT LEVEL. THIS WILL APPROACH...BUT
LIKELY FALL JUST A BIT SHORT OF LAKE WIND ADVISORY CRITERIA. MOS
VERY CLOSE TOO...BUT A LITTLE SHORT ALSO.
THE EDGE OF ANOTHER POLAR HIGH PRESSURE...CENTERED WELL TO OUR N
IN CANADA BRUSHES OUR AREA TONIGHT...GIVING CLEARING AND JUST A
LITTLE COLDER AIR BACK IN.
MODELS ARE QUICKER AND IN BETTER AGREEMENT WITH ANOTHER SYSTEM
ARRIVING WED AFTERNOON AND NIGHT. THEY HAVE TRENDED STRONGER AND
MUCH MOISTER TOO. SURFACE SYSTEM FORMS OVER W MT...AND MOVES ESE ACROSS
THE SC-SE MT BORDER WITH WY. FIRST IMPRESSIONS ARE THAT THIS COULD
ONLY IMPACT OUR EXTREME S...BUT THERE IS A SURPRISINGLY AMOUNT OF
LIFT AND MOISTURE FLUNG WELL N OF THAT...AS THERE IS A MODEST
INVERTED TROUGH. MODELS HAVE BEEN WAY TOO MOIST LATELY...AND
APPEAR THAT WAY AGAIN AS GFS HAS UP TO 0.4 QPF. HOWEVER THERE IS
DECENT AGREEMENT ON SIGNIFICANT QPF AND THE LOCATION...EXCEPT THE
NAM. SATELLITE CHANNELS SHOWING AN IMPRESSIVE LONG STREAM OF
MOISTURE INTO SEVERAL WAVES IN WESTERLY JET ACROSS MUCH OF THE PACIFIC.
SO...CHANCE POPS FOR MOST OF THE AREA FOR THIS SYSTEM APPEAR
REASONABLE.
THE AIR MASS NOT UNSTABLE WED NIGHT...SO WILL GO WITH STRATIFORM
LIGHT RAIN CHANCES. 850 MB TEMPS BELOW 0C IN OUR NORTHERN-MOST
ZONES...AND POSSIBLE LATE NIGHT ARRIVAL TIME FAVORABLE FOR
POSSIBLE SNOW IN PLACES. WILL LEAVE OUT ANY SNOW AMOUNTS THOUGH. FOR THE
REST OF THE AREA...IT COULD BE A RATHER COLD RAIN...AND NOT FAR
FROM TURNING TO SNOW. LINGERING PRECIP TURNS SHOWERY AS IT WARMS
UP AND TAPERS OFF IN THE THU AFTERNOON. SIMONSEN
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE EXTENDED BEINGS THURSDAY NIGHT WITH AN UPPER TROUGH MOVING OUT
OF THE REGION AND RIDGING BUILDING IN. STILL A FEW SHORTWAVES
NOTED IN THE FLOW TO KEEP A MENTION OF POPS GOING OVER THE REGION
THROUGH FRIDAY NIGHT. THIS WILL ALSO BE THE COOLEST PERIOD OF THE
FORECAST. DO NOT EXPECT MUCH QPF WITH ANY OF THE SHORT WAVES
MOVING THROUGH THE FLOW. BOTH THE EC AND GFS SEEM IN FAIR
AGREEMENT WITH THE PATTERN.
SATURDAY INTO EARLY NEXT WEEK... A LARGE RIDGE SETTLES IN OVER
NORTHEAST MONTANA. DRY IS FOR CERTAIN... TEMPERATURES DID STAY
SOMEWHAT CONSERVATIVE... BY MONDAY INTO TUESDAY WE COULD BE WELL
INTO THE 80S ACROSS EASTERN MONTANA. DO EXPECT SOME FIRE WEATHER
ISSUES EARLY NEXT WEEK. ANY RIPPLES IN THE UPPER FLOW OVER THE
MOUNTAINS COULD SPARK A THUNDERSTORM. THE MID LEVELS ARE FORECAST
TOO WARM FOR SURFACE CONVECTION. AT THIS TIME ITS JUST TOO FAR OUT
TO BE TRYING TO PREDICT VERY ISOLATED DRY THUNDERSTORMS. PROTON
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR ALL TAF SITES
THROUGHOUT THE ENTIRE TAF CYCLE. SOME ISOLATED RAIN SHOWERS CAN
BE EXPECTED ACROSS THE REGION INTO THIS EVENING...HOWEVER FLIGHT
CONDITIONS WOULD BE LOWERED TO MVFR ONLY IF ONE OF THESE SMALL
SHOWERS MOVE DIRECTLY OVER A TAF SITE. EXPECT VICINITY RAIN SHOWERS
NEAR KGGW AND KOLF BY MID AND NEAR KSDY AND KGDV BY MID AFTERNOON.
BREEZY WINDS FROM THE WEST THIS AFTERNOON WILL CALM FROM THE NORTH
TONIGHT. PROTON/BMICKELSON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR FOR FORT PECK
LAKE IN THE FORT PECK LAKE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1058 AM CDT TUE APR 17 2012
.DISCUSSION...
A FEW SPRINKLES CONTINUE ACROSS THE EASTERN HALF OF THE FORECAST
AREA. THESE SHOWERS ARE QUICKLY DIMINISHING AND SHOULD COME TO AN
END WITHIN THE NEXT HOUR OR AS THEY LOSE THE WEAK MID LEVEL SUPPORT.
UPDATED THE POPS THIS MORNING TO FOLLOW THESE SHOWERS ALONG WITH
MORE EXTENSIVE CLOUD COVERAGE ACROSS OUR EAST. HRRR AND NAM STILL
DEVELOPING SOME MUCAPE AROUND 500 J/KG WITH EFFECTIVE SHEAR
INCREASING TO AROUND 35 KT IN THE EARLY TO LATE AFTERNOON MAINLY
EAST OF I29. THE NAM IS SLIGHTLY BRING IN SLIGHTLY BROADER AREA OF
ELEVATED INSTABILITY EXTENDING EAST OF THE JAMES RIVER INTO OUR MN
AND IA COUNTIES. SLIGHTLY ADJUSTED THUNDERSTORM CHANCES TO FOCUS ON
MN AND IA FOR THIS AFTERNOON CLOSER WHERE THE BEST ELEVATED
INSTABILITY AND SHEAR LIES. BETTER OVERALL POTENTIAL FOR
PRECIPITATION WILL DEVELOP THIS EVENING AND OVERNIGHT.
&&
.AVIATION.../FOR THE 19Z TAF ISSUANCE/
OVERALL VFR CONDITIONS EXPECTED THROUGH 18Z/WED. BREEZY SOUTH WINDS
THIS AFTERNOON WILL TURN WEST THEN NORTHWEST LATE TONIGHT EARLY
WEDNESDAY BEHIND A FRONT. SCATTERED SHOWERS AND THUNDERSTORMS WILL
BE POSSIBLE EAST OF I29 THIS AFTERNOON WITH A BETTER CHANCE ACROSS
THE FORECAST AREA FROM 00Z TO 06Z. BRIEF AND ISOLATED LOWERING OF
CEILINGS TO 3K FEET AND VISIBILITIES TO 3-5SM WILL BE POSSIBLE UNDER
THUNDERSTORMS.
&&
.PREV DISCUSSION...
TEMPS HAVE FALLEN INTO THE 29 TO 35 DEGREE RANGE THUS FAR
OVERNIGHT...DESPITE THE PRESENCE OF POCKETS OF MID/UPPER CLOUD COVER.
THE FROST ADVISORY...WHICH EXISTS GENERALLY NORTH OF CHAMBERLAIN TO
HAWARDEN TO SPENCER LINE...LOOKS TO BE IN GOOD SHAPE THROUGH 8 AM
CDT. RETURN FLOW BECOMES REESTABLISHED TODAY...AND H85 TEMPERATURES
MODERATE TO BETWEEN +10C /SWRN MN/ AND +15C /SCNTRL SD/ ACROSS THE
FORECAST AREA. PROGGED MIXING YIELDS HIGHS IN THE MID 60S TO LOWER
70S. WEAK ELEVATED INSTABILITY DEVELOPS THIS AFTERNOON ON THE NOSE
OF THE INCREASING LLJ...SO COULD SEE SOME WIDELY SCT THUNDERSTORMS
OVER NWRN IA AND ADJACENT AREAS IN MN/SD/NE AFTER 21Z. PRECIPITATION
CHANCES THEN INCREASE DURING THE EVENING HOURS ACROSS THE FORECAST
AREA AS A SHORTWAVE TROUGH APPROACHES FROM THE WEST AND IS ALSO
REFLECTED IN THE LLVL PRESSURE FIELDS. THE SURFACE TROUGH WILL BE
DRAPED ACROSS THE DAKOTAS/NEBRASKA DURING THE PEAK OF DAYTIME
HEATING. ALTHOUGH MOISTURE RETURN WILL BE MODEST AT THAT
POINT...COULD STILL SEE A FEW STRONGER STORMS LATE THIS AFTERNOON
AND EVENING GIVEN THE SHEAR PROFILE WITH THE ADVANCING TROUGH.
SHOWERS AND THUNDERSTORM COVERAGE SHOULD INCREASE OVERNIGHT...AS A
DECENT AREA OF FORCING PASSES OVER THE AREA. SAID SHORTWAVE TROUGH
MARCHES ACROSS THE REGION AT A FAIRLY STEADY PACE...SO PRECIPITATION
IS EXPECTED TO HAVE ENDED BY DAYBREAK WEDNESDAY. LOW TEMPS WEDNESDAY
MORNING SHOULD BE ELEVATED IN THE LOWER 40S-50S RANGE GIVEN THE
EXTENSIVE CLOUD COVER. NOT A BIG SURGE OF COLD AIR BEHIND THIS WAVE
GIVEN THE CONTINUANCE OF THE SEMI-ZONAL FLOW REGIME...SO WEDNESDAY
HIGHS SHOULD BE ABLE TO RECOVER INTO THE LOW/MID 60S AND 70S. THE
NEXT SHORTWAVE WILL FOLLOW APPROXIMATELY 24 HOURS LATER...THIS TIME
WITH A SLIGHTLY MORE IMPRESSIVE ACCOMPANYING PV ANOMALY. THIS
FEATURE KICKS ACROSS THE REGION ON WEDNESDAY NIGHT AND
THURSDAY...WITH THE ATTENDANT SFC TROUGH NOSING INTO THE SOUTHERN
CWA. ALTHOUGH THERE ARE TEMPORAL/SPATIAL DIFFERENCES BETWEEN THE
MODEL SOLUTIONS...AM CONFIDENT ENOUGH TO GO WITH HIGH LIKELY POPS /70
PERCENT/ BETWEEN 06Z THURSDAY AND 00Z FRIDAY. HAVE LEANED TOWARD THE
LESS AGGRESSIVE GFS/ECMWF SOLUTIONS OVER THE FASTER NAM.
HIGH TEMPS ON FRIDAY SHOULD BE REDUCED BACK INTO THE 50S AS WEAK
TROUGHING PERSISTS...BUT THE PREVIOUSLY ADVERTISED WARM-UP LOOKS TO
BE ON TRACK AS RIDGING BUILDS INTO THE AREA INTO NEXT WEEK. AFTER THE
POSSIBILITY OF A FEW SHOWERS LATE FRIDAY INTO SATURDAY AS THE
TRANSITION OCCURS...DRY WEATHER IS EXPECTED ON SUNDAY AND MONDAY.
ADDITIONALLY...HIGHS WILL MODERATE FROM THE MID 50S/60S ON
SATURDAY...TO THE UPPER 60S/70S ON MONDAY AND TUESDAY...WHICH IS 10
TO 15 DEGREES ABOVE NORMAL FOR LATE APRIL.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
312 PM CDT TUE APR 17 2012
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
312 PM CDT TUE APR 17 2012
MAIN FORECAST CONCERN IS ON THE MULTITUDE OF PRECIPITATION CHANCES
THROUGHOUT THE SHORT TERM...ESPECIALLY THURSDAY NIGHT AND FRIDAY.
P-TYPE ALSO A CONCERN FOR THURSDAY NIGHT AND FRIDAY.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED NEARLY ZONAL FLOW ACROSS MUCH OF THE COUNTRY WITH PERHAPS
SOME WEAK RIDGING OVER IDAHO AND MINNESOTA. IN-BETWEEN THESE TWO
WEAK RIDGES...A FAIRLY POTENT SHORTWAVE TROUGH IS NOTED OVER CENTRAL
MONTANA. DOWNSTREAM OF THIS SHORTWAVE...MID CLOUDS HAVE BEEN
SPREADING EAST ACROSS THE DAKOTAS AND MINNESOTA. NO PRECIPITATION AS
OF YET...DUE TO DRY AIR SEEN ON THE 12Z BIS SOUNDING BELOW 600MB.
HOWEVER...SOUTHERLY 925MB WINDS OF 10 TO 20 KT IS SLOWLY BRINGING
MORE LOW LEVEL MOISTURE NORTHWARD. DEWPOINTS HAVE CLIMBED INTO THE
MID 40S OVER MUCH OF EASTERN SOUTH DAKOTA. FARTHER SOUTHEAST...
ISENTROPIC LIFT ON THE 295K SURFACE HAS RESULTED IN SCATTERED MID-
CLOUD DEVELOPMENT OVER IOWA AND SOUTHERN MINNESOTA. MOSTLY SUNNY
SKIES OVER THE FORECAST AREA COMBINED WITH 850MB TEMPS SLOWLY
RISING...WHICH WERE 0 TO -7C PER 12Z RAOB ANALYSIS...HAS HELPED
PUSH TEMPERATURES INTO THE 50S TO LOW 60S.
TONIGHT AND WEDNESDAY...FOCUS IS ON THE POTENT SHORTWAVE TROUGH.
MODELS REMAIN REMARKABLY CONSISTENT ON THIS TROUGH TRACKING
EAST...REACHING WESTERN UPPER MICHIGAN BY 18Z WEDNESDAY. AS THE
TROUGH APPROACHES TONIGHT...A STRONG SURGE OF 850MB MOISTURE
TRANSPORT COMES UP AHEAD OF IT. PRECIPITABLE WATER CLIMBS TO 0.75 TO
1 INCH BY 12Z WEDNESDAY...A JUMP FROM 0.3 TO 0.6 INCHES NOW. THIS
SURGE OF MOISTURE COMBINED WITH DPVA/HEIGHT FALLS ASSOCIATED WITH
THE TROUGH (30-70 METERS IN 12 HOURS) WILL LIKELY LEAD TO THE
DEVELOPMENT OF A NARROW WARM CONVEYOR BELT OF SHOWERS. MUCAPE VALUES
ARE LESS THAN 300 J/KG...WHICH IS A THIN CAPE TOO ON SOUNDINGS...SO
ANTICIPATE AT MOST JUST SOME SCATTERED EMBEDDED THUNDERSTORMS. GIVEN
VERY PERSISTENT SIGNAL ON PRECIPITATION TONIGHT INTO WEDNESDAY
MORNING...HAVE RAISED PRECIPITATION CHANCES TO 100...WITH THE PEAK
TIME OF PRECIPITATION EXPECTED BETWEEN 09-15Z WEDNESDAY. DURING THE
LATE MORNING AND AFTERNOON...A DRY SLOT IS PROGGED TO COME IN BEHIND
THE SHORTWAVE TROUGH...WHICH WHEN COMBINED WITH THE SURFACE FRONT
PUSHING EAST SHOULD END PRECIPITATION OVER THE NORTHWEST HALF OF THE
AREA. OVER THE SOUTHEAST HALF...THE COLD FRONT ENDS UP SLOWING DOWN
AS THE TROUGH PULLS AWAY. COULD SEE ADDITIONAL DIURNAL DEVELOPMENT
OF SHOWERS AND STORMS ALONG THIS FRONT AS CAPE JUMPS TO AROUND 500
J/KG. THEREFORE...CHANCES OF PRECIPITATION REMAIN IN THE SOUTHEAST
HALF IN THE AFTERNOON...MAINLY IN THE 40-50 RANGE. WITH INCREASING
WARM ADVECTION TONIGHT...LOWS LIKELY TO OCCUR IN THE EVENING WITH A
SLOW RISE THEREAFTER. NEEDLESS TO SAY...A MUCH WARMER NIGHT
TONIGHT. ON WEDNESDAY...A SURGE OF 6-8C 850MB TEMPS COMING UP
WITH THE TROUGH COMBINED WITH SUN SHOULD ALLOW FOR HIGHS IN THE
60S TO POSSIBLY LOW 70S.
WEDNESDAY NIGHT AND THURSDAY...FOLLOWED THE PREVIOUS FORECAST IN
MAINTAINING A 20 PERCENT CHANCE DOWN IN THE FAR SOUTHEAST SECTION OF
THE FORECAST AREA WEDNESDAY EVENING...TO ACCOUNT FOR THE SLOW MOVING
COLD FRONT AND ANY LINGERING SHOWERS/STORMS ON IT. A SURFACE RIDGE
OF HIGH PRESSURE BUILDS IN ELSEWHERE BEHIND THE FRONT...LEADING TO
DRY CONDITIONS FOR THE EVENING. ATTENTION THEN FOCUSES ON A
SHORTWAVE TROUGH JUST OFF THE PACIFIC NORTHWEST COAST. ON WEDNESDAY
NIGHT...THIS TROUGH ALONG WITH A FEW OTHERS COMING OFF THE PACIFIC
HELP DEVELOP A BROAD TROUGH ALONG THE LEE SIDE OF THE ROCKIES. IN
RESPONSE...MOISTURE TRANSPORT...ISENTROPIC LIFT AND LOW TO MID LEVEL
FRONTOGENESIS INCREASES DOWNSTREAM...LEADING TO PRECIPITATION
DEVELOPMENT. PRIOR TO 12Z THURSDAY...MUCH OF THIS PRECIPITATION
LOOKS TO BE CONFINED TO THE DAKOTAS INTO IOWA. DID MAINTAIN THE
20-30 PERCENT CHANCES MAINLY WEST OF THE RIVER LATE WEDNESDAY NIGHT
IN CASE THE PRECIPITATION SPREADS IN QUICKER. MUCH BETTER SHOT FOR
PRECIPITATION EXISTS ON THURSDAY AS THE LOW TO MID LEVEL
FRONTOGENESIS TIGHTENS THROUGH THE DAY OVER THE AREA. IN
ADDITION...THERE ARE INDICATIONS THAT IN THE AFTERNOON AN UPPER
LEVEL JET STREAK DEVELOPING OVER NORTHERN WISCONSIN. THIS WOULD BE
VERY FAVORABLE FOR PRECIPITATION. LASTLY...LOW LEVEL MOISTURE
TRANSPORT NORTH OF A DEVELOPING WARM FRONT NEAR US-20 SHOULD BRING
SOME INSTABILITY INTO THE FRONTOGENESIS ZONE. THEREFORE...HAVE
MAINTAINED THE THUNDER CHANCES. TEMPERATURES DEFINITELY COOLER
DURING THIS TIME PERIOD...ESPECIALLY NORTH OF I-90 WHERE A NORTHEAST
FLOW WILL HELP TO FEED COOL AIR IN. WILL HAVE TO WATCH TEMPERATURES
WHEN THE PRECIPITATION STARTS...AS THEY MAY FALL DUE TO THE FEED OF
30S DEWPOINTS INTO THE AREA. HOWEVER...DID NOT INCLUDE ANY
NON-DIURNAL TREND GIVEN THE 17.12Z ECMWF/CANADIAN/UKMET WHICH IS
FARTHER NORTH WITH THE WARMER AIR.
THURSDAY NIGHT AND FRIDAY...FOCUS CONTINUES ON THE STRENGTHENING
FRONTOGENESIS ZONE OVER THE AREA FROM THURSDAY AFTERNOON. ALL MODELS
ARE WELL AGREED UPON THAT THE TROUGHING OVER THE ROCKIES WILL DIG
DOWN INTO THE CENTRAL PLAINS THURSDAY NIGHT. HOWEVER...THE 17.12Z
GFS/NAM ARE MORE PROGRESSIVE WITH EXITING THE FRONTOGENESIS ZONE TO
THE EAST AND SOUTHEAST THAN THE 17.12Z ECMWF/UKMET/CANADIAN. AM
CONCERNED THE GFS/NAM ARE TOO PROGRESSIVE. IF SO...THE NON-NCEP
MODEL GROUP WOULD YIELD A LOT MORE PRECIPITATION THURSDAY NIGHT...
ESPECIALLY FROM NORTHEAST IOWA TO GREEN BAY. THEY SHOW ANYWHERE FROM
1 TO 2 INCHES OF RAINFALL. THE NORTH EDGE OF SOME OF THIS...SAY IN
CENTRAL AND NORTHERN WISCONSIN...IS LIKELY TO MIX WITH OR CHANGE
OVER TO SNOW AS CONTINUED DRY/COOL AIR FEED AND DYNAMIC COOLING HELP
LOWER THE THERMODYNAMIC PROFILE TEMPERATURES. TOO EARLY TO SAY HOW
MUCH SNOW SAY COULD ACCUMULATE IN TAYLOR COUNTY...WHICH IS MOST
LIKELY TO SEE SNOW...BUT SOMETHING TO KEEP AN EYE ON. IN ANY
EVENT...HAVE LEANED THE FORECAST FOR THIS PERIOD TOWARDS THE
ECMWF/UKMET/CANADIAN...WHICH RESULTS IN AN INCREASE IN PRECIPITATION
CHANCES AND QPF FOR BOTH THURSDAY NIGHT AND FRIDAY. FURTHER
INCREASES MAY BE NECESSARY...ESPECIALLY IF THE GFS/NAM COME AROUND.
FOR TEMPERATURES...TOOK A BLEND OF GUIDANCE FOR NOW UNTIL MODELS CAN
SETTLE DOWN.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
312 PM CDT TUE APR 17 2012
17.12Z ECMWF/GFS AND GFS ENSEMBLES ARE IN GOOD AGREEMENT SUGGESTING
THAT THE TROUGH DIGGING DOWN THROUGH THE CENTRAL PLAINS THURSDAY
NIGHT AND FRIDAY ENDS UP CLOSING OFF NEAR THE GULF COAST FOR
SATURDAY. THIS IS AN IMPORTANT CHANGE AS NOW THE TROUGHING OVER THE
FORECAST AREA FOR THE WEEKEND IS NOT NEARLY AS DEEP. COMPARE THIS TO
THE 17.12Z CANADIAN WHICH DEVELOPS A FULL-BLOWN EASTERN TROUGH THAT
LOOKS VERY COLD. THIS MODEL SCENARIO APPEARS TO BE AN OUTLIER AND
WAS DISCOUNTED. FOLLOWING THE MAIN MODEL GROUP...MUCH OF FRIDAY
NIGHT THROUGH MONDAY SHOULD BE DRY WITH THE AREA DOMINATED BY
SURFACE HIGH PRESSURE IN THE WAKE OF FRIDAYS FRONTOGENESIS ZONE.
MAY HAVE TO DEAL WITH A LITTLE LIGHT PRECIP SATURDAY NIGHT...
ASSOCIATED WITH A SHORTWAVE COMING DOWN THROUGH THE NORTHWEST
FLOW. ALSO...WITH WITH THE RIDGE BUILDING FRIDAY NIGHT...LOCATIONS
ALONG AND NORTH OF I-94 MAY HAVE TO CONTEND WITH ANOTHER FREEZE.
RIDGING THAT DEVELOPS DURING THE WEEKEND OVER THE WESTERN U.S.
IS FORECAST TO PUSH EASTWARD MONDAY INTO TUESDAY...DUE TO A POTENT
SHORTWAVE TROUGH DROPPING INTO THE PACIFIC NORTHWEST. THE RIDGING
WILL HELP TO PUSH WARMER AIR INTO THE AREA...WITH TEMPERATURES
LIKELY CLIMBING ABOVE NORMAL. CONVECTION COULD OCCUR LATE TUESDAY
AS A WARM FRONT / LOW PRESSURE SYSTEM OVER THE NORTHERN PLAINS
MOVES INTO OUR REGION.
&&
.AVIATION...THROUGH 18Z WEDNESDAY
1237 PM CDT TUE APR 17 2012
HIGH PRESSURE WILL MOVE EAST OF THE REGION THIS AFTERNOON AS LOW
PRESSURE DEEPENS OVER THE DAKOTAS. THE LOW IS EXPECTED TO MOVE INTO
NORTHERN MINNESOTA THIS EVENING. THE PRESSURE GRADIENT WILL TIGHTEN
OVER THE AREA...WITH SOUTH WINDS INCREASING INTO THE 15 TO 20 KT
RANGE THIS EVENING. A COLD FRONT IS EXPECTED TO MOVE THROUGH THE
AREA LATE TONIGHT INTO EARLY WEDNESDAY MORNING BRINGING SHOWERS
AND PERHAPS AN ISOLATED THUNDERSTORM OR TWO TO THE TAF SITES. PLAN
ON MVFR CONDITIONS TONIGHT AS LOW LEVEL MOISTURE STREAMS INTO THE
REGION AHEAD OF THE FRONT...WITH CEILINGS LOWERING INTO THE 2-3KFT
RANGE. WINDS WILL SWITCH TO THE SOUTHWEST BY MID WEDNESDAY MORNING
AS THE FRONT PASSES THROUGH...SWITCHING TO THE WEST BEHIND THE
FRONT. LOOK FOR CEILINGS TO IMPROVE TO VFR BY LATE WEDNESDAY
MORNING...IMPROVING TO AROUND 4KFT. FORECAST SOUNDINGS AT KLSE
ARE SHOWING MORE INSTABILITY OVER THE PREVIOUS GUIDANCE.
THUNDERSTORMS MAY NEED TO BE INCLUDED AT THE KLSE TAF STARTING AT
18Z IF THE INCREASE IN INSTABILITY MATERIALIZES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
312 PM CDT TUE APR 17 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP