Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/18/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1210 PM MDT TUE APR 16 2013
.UPDATE...
&&
.SHORT TERM...TAKING A CLOSER LOOK AT THE LATEST MODELS...NOW
APPEARS THE DEVELOPMENT OF SNOW ACROSS THE PLAINS MAY BE DELAYED A BIT
LONGER OVERNIGHT...PERHAPS NOT UNTIL 10Z. WILL KEEP THE BETTER
POPS AND WEATHER TOWARDS THE WYOMING BODER.
.AVIATION...LATEST MODELS NOW SHOWING WINDS GO COUNTERCLOCKWISE
LATER THIS EVENING AND OVERNIGHT WHICH COULD BRING SOME LOW
STRATUS AND PERHAPS FOG ACROSS THE AREA AIRPORTS AFTER 06Z. IT
ALSO APPEARS THE DEVELOPMENT OF LIGHT SNOW MAY ALSO BE DELAYED.
LATEST TAFS INDICATE THIS LATEST CHANCE. STILL POTENTIAL FOR 2 TO
4 INCHES ACROSS DENVER AREA BY 00Z.
&&
.PREV DISCUSSION... /ISSUED 1059 AM MDT TUE APR 16 2013/
UPDATE...
SHORT TERM...STILL SEEMS FROM WEB CAMS THAT A FEW FLURRIES STILL
ONGOING ALONG THE CHEYENNE RIDGE AS WELL AS THE FOOTHILLS...THOUGH
HAVE BEEN ON THE DECREASE. ALSO APPEARS ANY FREEZING DRIZZLE
THREAT HAS ENDED. SOUTHEAST WINDS CURRENTLY CRANKING ACROSS
MUCH OF THE PLAINS...WITH SOME GUSTS AROUND 30 KTS FROM DENVER
AREA EASTWARD. WEAK CYCLONE NORTH OF DENVER KEEPING LIGHT
NORTHWEST WINDS NORTHWEST DENVER SUBURBS. OTHERWISE...SOUTHWEST
FLOW ALOFT PREVAILING THROUGH TONIGHT AS UPPER TROUGH DIGS INTO
THE GREAT BASIN. SOUTHEAST WINDS EXPECTED TO CONTINUE THROUGH THE
DAY ACROSS THE PLAINS WITH UPPER TROUGH OVER GREAT BASIN. AIRMASS
BECOMES SLIGHTLY UNSTABLE DURING THE AFTERNOON WITH LAPSE RATES
APPROACHING 8 C/KM OVER MOUNTAINS AND AROUND 7 C/KM IN THE MID
LEVELS ACROSS PLAINS. STILL SOME CHANCE OF SHOWERS THIS AFTERNOON
MAINLY OVER THE MOUNTAINS...WILL CONTINUE CURRENT POPS AND WEATHER
TRENDS THERE. AS FOR PLAINS...SCATTERED POPS MAY BE A BIT OVERDONE
THROUGH 00Z BASED ON LATEST RAP. BUT THERE WILL BE SOME INCREASE
IN MID LEVEL QG ASCENT WHICH COULD PROVIDE SOME CONVECTIVE
ELEMENTS WITH THE BEST CHANCE TO BE IN AND NEAR NORTHERN FOOTHILLS.
LATEST MODELS STILL POINTING TOWARD NORTHERN MOUNTAINS AND
NORTHERN FOOTHILLS TONIGHT FOR DECENT SNOW FALL WITH POTENTIAL FOR
JET DYNAMICS AND CSI. AT SOME POINT...MAY NEED AN ADVISORY FOR
ZONES 30..32 AND 34 TONIGHT AS CSI BANDS COULD SET UP THERE. WILL
ADDRESS THIS FOR THE AFTERNOON PACKAGE. OVERALL...CURRENT
FORECASTS SEEM ON TRACK...WITH PERHAPS A BIT MORE WIND NEEDED
ACROSS PLAINS. TEMPERATURES LOOK REASONABLE.
$$
,AVIATION...SOME FOG AND OR HAZE STILL FLOATING AROUND AREA
AIRPORTS...WILL KEEP A MENTION THROUGH 19Z. SOUTHEAST WINDS
CURRENTLY GUSTING TO AROUND 25-30 KTS AT KDEN AND KAPA...WHICH
SHOULD CONTINUE THROUGH THE AFTERNOON PER LATEST RAP AND HRRR.
CYCLONE NORTH OF DENVER TO PERSIST THROUGH THE DAY...SHOULD KEEP
LIGHT NORTHWEST WINDS AT KBJC. OTHERWISE...CURRENT TAF TRENDS SEEM
ON TRACK. CEILINGS TO GRADUALLY IMPROVE...STILL 5000-6000 FOOT
CEILINGS TO PREVAIL. A FEW SHOWERS POSSIBLE ALONG FOOTHILLS DURING
THE AFTERNOON AND EVENING. BETTER CHANCE FOR SNOW SHOWERS AT AREA
AIRPORTS AFTER MIDNIGHT TONIGHT. ACCUMULATION SNOW POSSIBLE DURING
THE DAY WEDNESDAY WHEN DEEPER UPSLOPE FLOW DEVELOPS WITH 2 TO 4
INCHES POSSIBLE BY 00Z.
PREV DISCUSSION... /ISSUED 428 AM MDT TUE APR 16 2013/
SHORT TERM...HEAVY SNOW BAND ALONG WITH THE UPPER LEVEL JET HAD
SHIFTED NORTH INTO WYOMING EARLY THIS MORNING. AS A RESULT...
EXISTING WINTER STORM HIGHLIGHTS HAVE BEEN CANCELLED. BEHIND
THIS...THERE WERE STILL SNOW SHOWERS MAINLY IN THE NORTHERN
MOUNTAINS AND NORTHERN FRONT RANGE FOOTHILLS. SOME FREEZING
DRIZZLE HAD ALSO DEVELOPED ACROSS THE PLAINS WITH MOIST LOW LEVEL
EASTERLY UPSLOPE FLOW. LACK OF SEEDERS ALOFT SHOULD KEEP THREAT OF
FREEZING DRIZZLE IN THE FORECAST THIS MORNING.
ATTENTION THEN TURNS TOWARD CONVECTIVE SHOWER DEVELOPMENT THIS
AFTERNOON WHICH SHOULD AFFECT MAINLY THE MOUNTAIN AREAS WHERE
INSTABILITY IS SUFFICIENT. BY THIS EVENING...THE VARIOUS SHORT AND
MEDIUM RANGE MODELS SUGGEST A DEEPER SOUTHEAST FLOW DEVELOPING
WHICH FAVORS THE NORTHERN FRONT RANGE FOOTHILLS FOR PRECIP. THE
POTENTIAL FOR HEAVY SNOWFALL LIKELY DEPENDS ON LOCATION OF UPPER
JET AND DRY SLOT...WHICH AT THIS TIME SHOULD BE JUST FAR ENOUGH
SOUTH TO BRING HEAVY SNOW THREAT BACK INTO THE NORTHERN TIER OF
MOUNTAINS AND THE LARIMER COUNTY FOOTHILLS LATER THIS AFTERNOON
THROUGH TONIGHT. AT THIS POINT...THE PROBABILITY IS HIGH ENOUGH TO
ISSUE ANOTHER WINTER STORM WARNING BEGINNING IN THOSE LOCATIONS
LATER THIS AFTERNOON. AGAIN...THERE WILL LIKELY BE ANOTHER VERY
SHARP CUTOFF OF SIGNIFICATION PRECIPITATION JUST SOUTH OF THE JET
SO SITUATION WILL NEED TO MONITORED CLOSELY.
ON THE PLAINS...LOW LEVEL SOUTHEAST FLOW WILL STRENGTHEN
CONSIDERABLY TODAY. HOWEVER...COOLER BOUNDARY LAYER FLOW SHOULD
REMAIN IN PLACE WITH PLENTY OF LOW LEVEL MOISTURE...CLOUDINESS...
AND SNOW IN AREAS THAT SAW THE HEAVY ACCUMULATIONS YESTERDAY. THE
SOUTHEAST FLOW AND SNOWPACK LOCATION SHOULD SET UP A STRONG DENVER
CYCLONE THIS AFTERNOON...KEEPING COLD AIR IN PLACE FROM THE
WESTERN SECTIONS OF DENVER NORTHWARD TO FORT COLLINS. COULD SEE A
FEW RAIN OR SNOW SHOWERS DRIFT OFF THE FRONT RANGE LATER THIS
AFTERNOON BUT BETTER CHANCE OF SNOW DEVELOPING WILL OCCUR LATER
TONIGHT AS MOISTURE BEGINS TO DEEPEN AHEAD OF DIGGING TROUGH.
LONG TERM...UPPER TROUGH DRAPED OVER THE GREAT BASIN WILL MOVE
SOUTHEAST WEDNESDAY AND SEND A COLD FRONT RACING DOWN NORTHEASTERN
COLORADO DURING THE MORNING. UPSLOPE FLOW WILL FORM AGAINST THE
FOOTHILLS DURING THE DAY TO KEEP SNOW GOING THROUGH THE AFTERNOON
AT LEAST. SNOW WILL SPREAD OVER THE PLAINS BEHIND THE FRONT AND
AS THE UPSLOPE DEEPENS. NORTH WINDS BEHIND THE FRONT...GUSTING 30 TO
40 MPH OVER THE PLAINS WILL REMAIN THROUGHOUT WEDNESDAY DAY TO
CREATE SOME AREAS OF BLOWING AND DRIFTING SNOW. RIGHT NOW WILL NOT
ISSUE ANY HIGHLIGHTS AS THERE MAY BE A PERIOD OF RAIN MIXED WITH
SNOW OVER THE PLAINS LIMITING THE AMOUNT OF BLOWING SNOW. OTHERWISE
ALL PRECIP IS EXPECTED TO BE SNOW AS 700 TEMPS OF -14 CELSIUS
SPREAD IN BEHIND THE FRONT. THE 700 MB LOW WILL TRANSITION OVER
THE COLORADO PLAINS SOMETIME LATE AFTERNOON INTO THE
EVENING...WHICH WILL BEGIN TO DIMINISH THE SNOW FROM NORTHWEST TO
SOUTHEAST. SNOW SHOULD BE DIMINISHED JUST AFTER SUNSET IN MOST
AREAS EXCEPT THE FAR EASTERN PLAINS AND SOME LIGHT SNOW OVER THE
MOUNTAINS...UNLESS THIS SYSTEM DIGS A LITTLE FARTHER SOUTH AND
DEEPER WHICH WOULD SLOW IT DOWN. OVERALL...AMOUNTS WEDNESDAY AND
WEDNESDAY NIGHT LOOK TO BE ABOUT 2-5 INCHES OVER THE PLAINS AND
3-9 INCHES OVER THE MOUNTAINS...WITH THE LOWER AMOUNTS IN THE
VALLEYS. TEMPERATURES WEDNESDAY NIGHT WILL LIKELY BE IN THE TEENS
OVER THE PLAINS TO SINGLE DIGITS OVER THE MOUNTAINS.
THE UPPER LOW WILL MOVE EAST OF THE AREA THURSDAY. SHOULD SEE
SNOW SLOWLY DIMINISHING OVER THE MOUNTAINS AND A CHANCE OF SNOW
CONTINUING OVER THE FAR EASTERN PLAINS...BUT SHOULD BE DONE BY
LATE AFTERNOON. TEMPERATURES WILL BE WARMING SLIGHTLY BUT WILL
STILL BE AROUND 20 TO 30 DEGREES BELOW NORMAL. FRIDAY WILL
CONTINUE THE WARMING AND DRYING TREND AS A WEAK UPPER RIDGE BUILDS
OVERHEAD.
SATURDAY THROUGH MONDAY WILL FEATURE A COUPLE DISTURBANCES IN THE
NORTHWEST FLOW ALOFT TO BRING A RETURN TO UNSETTLED WEATHER. WILL
SEE AN INCREASE IN THE CHANCES OF PRECIPITATION AGAIN FOR THE
AREA. TEMPERATURES WILL BE BACK TOWARD NORMAL....BUT STILL
SLIGHTLY BELOW AVERAGE. THEREFORE WILL EXPECT MORE RAIN FOR THE
PLAINS AND CONTINUED RAIN MIXED WITH SNOW FOR THE MOUNTAINS.
AVIATION...AREAS OF IFR/LIFR CEILINGS EXPECTED ACROSS THE FRONT
RANGE AIRPORTS THIS MORNING ALONG WITH A THREAT OF LIGHT FREEZING
DRIZZLE GIVEN TEMP/MOISTURE PROFILE IN PLACE. IF WE SEE ANY SNOW
WE DO NOT SEE ANY THREAT OF ACCUMULATION WITH ONLY FLURRIES
POSSIBLE. CEILING SHOULD GRADUALLY LIFT TODAY AT KDEN AND KAPA
WITH POSSIBLE EAST/SOUTHEAST WINDS GUSTING TO AROUND 25KTS. KBJC
WILL LIKELY SEE LOWER PREVAILING CONDITIONS ON BACK SIDE OF
CYCLONE. CHANCE THAT WINDS GO BACK TO NORTH OR NORTHWEST AT KAPA
AND KDEN THIS AFTERNOON DEPENDING ON INTENSITY OF DENVER CYCLONE
THAT DEVELOPS. BEST CHANCE OF SNOW WILL BE AFTER MIDNIGHT TONIGHT
AND MAINLY WEDNESDAY WHEN DEEPER UPSLOPE FLOW OCCURS. COULD SEE
ANOTHER 2-5 INCHES OF SNOW LATE TONIGHT/WEDNESDAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO MIDNIGHT MDT
WEDNESDAY NIGHT FOR COZ031-033-035.
&&
$$
SHORT TERM...D-L
LONG TERM....KRIEDERMAN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1059 AM MDT TUE APR 16 2013
.UPDATE...
&&
.SHORT TERM...STILL SEEMS FROM WEB CAMS THAT A FEW FLURRIES STILL
ONGOING ALONG THE CHEYENNE RIDGE AS WELL AS THE FOOTHILLS...THOUGH
HAVE BEEN ON THE DECREASE. ALSO APPEARS ANY FREEZING DRIZZLE
THREAT HAS ENDED. SOUTHEAST WINDS CURRENTLY CRANKING ACROSS
MUCH OF THE PLAINS...WITH SOME GUSTS AROUND 30 KTS FROM DENVER
AREA EASTWARD. WEAK CYCLONE NORTH OF DENVER KEEPING LIGHT
NORTHWEST WINDS NORTHWEST DENVER SUBURBS. OTHERWISE...SOUTHWEST
FLOW ALOFT PREVAILING THROUGH TONIGHT AS UPPER TROUGH DIGS INTO
THE GREAT BASIN. SOUTHEAST WINDS EXPECTED TO CONTINUE THROUGH THE
DAY ACROSS THE PLAINS WITH UPPER TROUGH OVER GREAT BASIN. AIRMASS
BECOMES SLIGHTLY UNSTABLE DURING THE AFTERNOON WITH LAPSE RATES
APPROACHING 8 C/KM OVER MOUNTAINS AND AROUND 7 C/KM IN THE MID
LEVELS ACROSS PLAINS. STILL SOME CHANCE OF SHOWERS THIS AFTERNOON
MAINLY OVER THE MOUNTAINS...WILL CONTINUE CURRENT POPS AND WEATHER
TRENDS THERE. AS FOR PLAINS...SCATTERED POPS MAY BE A BIT OVERDONE
THROUGH 00Z BASED ON LATEST RAP. BUT THERE WILL BE SOME INCREASE
IN MID LEVEL QG ASCENT WHICH COULD PROVIDE SOME CONVECTIVE
ELEMENTS WITH THE BEST CHANCE TO BE IN AND NEAR NORTHERN FOOTHILLS.
LATEST MODELS STILL POINTING TOWARD NORTHERN MOUNTAINS AND
NORTHERN FOOTHILLS TONIGHT FOR DECENT SNOW FALL WITH POTENTIAL FOR
JET DYNAMICS AND CSI. AT SOME POINT...MAY NEED AN ADVISORY FOR
ZONES 30..32 AND 34 TONIGHT AS CSI BANDS COULD SET UP THERE. WILL
ADDRESS THIS FOR THE AFTERNOON PACKAGE. OVERALL...CURRENT
FORECASTS SEEM ON TRACK...WITH PERHAPS A BIT MORE WIND NEEDED
ACROSS PLAINS. TEMPERATURES LOOK REASONABLE.
$$
,AVIATION...SOME FOG AND OR HAZE STILL FLOATING AROUND AREA
AIRPORTS...WILL KEEP A MENTION THROUGH 19Z. SOUTHEAST WINDS
CURRENTLY GUSTING TO AROUND 25-30 KTS AT KDEN AND KAPA...WHICH
SHOULD CONTINUE THROUGH THE AFTERNOON PER LATEST RAP AND HRRR.
CYCLONE NORTH OF DENVER TO PERSIST THROUGH THE DAY...SHOULD KEEP
LIGHT NORTHWEST WINDS AT KBJC. OTHERWISE...CURRENT TAF TRENDS SEEM
ON TRACK. CEILINGS TO GRADUALLY IMPROVE...STILL 5000-6000 FOOT
CEILINGS TO PREVAIL. A FEW SHOWERS POSSIBLE ALONG FOOTHILLS DURING
THE AFTERNOON AND EVENING. BETTER CHANCE FOR SNOW SHOWERS AT AREA
AIRPORTS AFTER MIDNIGHT TONIGHT. ACCUMULATION SNOW POSSIBLE DURING
THE DAY WEDNESDAY WHEN DEEPER UPSLOPE FLOW DEVELOPS WITH 2 TO 4
INCHES POSSIBLE BY 00Z.
&&
.PREV DISCUSSION... /ISSUED 428 AM MDT TUE APR 16 2013/
SHORT TERM...HEAVY SNOW BAND ALONG WITH THE UPPER LEVEL JET HAD
SHIFTED NORTH INTO WYOMING EARLY THIS MORNING. AS A RESULT...
EXISTING WINTER STORM HIGHLIGHTS HAVE BEEN CANCELLED. BEHIND
THIS...THERE WERE STILL SNOW SHOWERS MAINLY IN THE NORTHERN
MOUNTAINS AND NORTHERN FRONT RANGE FOOTHILLS. SOME FREEZING
DRIZZLE HAD ALSO DEVELOPED ACROSS THE PLAINS WITH MOIST LOW LEVEL
EASTERLY UPSLOPE FLOW. LACK OF SEEDERS ALOFT SHOULD KEEP THREAT OF
FREEZING DRIZZLE IN THE FORECAST THIS MORNING.
ATTENTION THEN TURNS TOWARD CONVECTIVE SHOWER DEVELOPMENT THIS
AFTERNOON WHICH SHOULD AFFECT MAINLY THE MOUNTAIN AREAS WHERE
INSTABILITY IS SUFFICIENT. BY THIS EVENING...THE VARIOUS SHORT AND
MEDIUM RANGE MODELS SUGGEST A DEEPER SOUTHEAST FLOW DEVELOPING
WHICH FAVORS THE NORTHERN FRONT RANGE FOOTHILLS FOR PRECIP. THE
POTENTIAL FOR HEAVY SNOWFALL LIKELY DEPENDS ON LOCATION OF UPPER
JET AND DRY SLOT...WHICH AT THIS TIME SHOULD BE JUST FAR ENOUGH
SOUTH TO BRING HEAVY SNOW THREAT BACK INTO THE NORTHERN TIER OF
MOUNTAINS AND THE LARIMER COUNTY FOOTHILLS LATER THIS AFTERNOON
THROUGH TONIGHT. AT THIS POINT...THE PROBABILITY IS HIGH ENOUGH TO
ISSUE ANOTHER WINTER STORM WARNING BEGINNING IN THOSE LOCATIONS
LATER THIS AFTERNOON. AGAIN...THERE WILL LIKELY BE ANOTHER VERY
SHARP CUTOFF OF SIGNIFICATION PRECIPITATION JUST SOUTH OF THE JET
SO SITUATION WILL NEED TO MONITORED CLOSELY.
ON THE PLAINS...LOW LEVEL SOUTHEAST FLOW WILL STRENGTHEN
CONSIDERABLY TODAY. HOWEVER...COOLER BOUNDARY LAYER FLOW SHOULD
REMAIN IN PLACE WITH PLENTY OF LOW LEVEL MOISTURE...CLOUDINESS...
AND SNOW IN AREAS THAT SAW THE HEAVY ACCUMULATIONS YESTERDAY. THE
SOUTHEAST FLOW AND SNOWPACK LOCATION SHOULD SET UP A STRONG DENVER
CYCLONE THIS AFTERNOON...KEEPING COLD AIR IN PLACE FROM THE
WESTERN SECTIONS OF DENVER NORTHWARD TO FORT COLLINS. COULD SEE A
FEW RAIN OR SNOW SHOWERS DRIFT OFF THE FRONT RANGE LATER THIS
AFTERNOON BUT BETTER CHANCE OF SNOW DEVELOPING WILL OCCUR LATER
TONIGHT AS MOISTURE BEGINS TO DEEPEN AHEAD OF DIGGING TROUGH.
LONG TERM...UPPER TROUGH DRAPED OVER THE GREAT BASIN WILL MOVE
SOUTHEAST WEDNESDAY AND SEND A COLD FRONT RACING DOWN NORTHEASTERN
COLORADO DURING THE MORNING. UPSLOPE FLOW WILL FORM AGAINST THE
FOOTHILLS DURING THE DAY TO KEEP SNOW GOING THROUGH THE AFTERNOON
AT LEAST. SNOW WILL SPREAD OVER THE PLAINS BEHIND THE FRONT AND
AS THE UPSLOPE DEEPENS. NORTH WINDS BEHIND THE FRONT...GUSTING 30 TO
40 MPH OVER THE PLAINS WILL REMAIN THROUGHOUT WEDNESDAY DAY TO
CREATE SOME AREAS OF BLOWING AND DRIFTING SNOW. RIGHT NOW WILL NOT
ISSUE ANY HIGHLIGHTS AS THERE MAY BE A PERIOD OF RAIN MIXED WITH
SNOW OVER THE PLAINS LIMITING THE AMOUNT OF BLOWING SNOW. OTHERWISE
ALL PRECIP IS EXPECTED TO BE SNOW AS 700 TEMPS OF -14 CELSIUS
SPREAD IN BEHIND THE FRONT. THE 700 MB LOW WILL TRANSITION OVER
THE COLORADO PLAINS SOMETIME LATE AFTERNOON INTO THE
EVENING...WHICH WILL BEGIN TO DIMINISH THE SNOW FROM NORTHWEST TO
SOUTHEAST. SNOW SHOULD BE DIMINISHED JUST AFTER SUNSET IN MOST
AREAS EXCEPT THE FAR EASTERN PLAINS AND SOME LIGHT SNOW OVER THE
MOUNTAINS...UNLESS THIS SYSTEM DIGS A LITTLE FARTHER SOUTH AND
DEEPER WHICH WOULD SLOW IT DOWN. OVERALL...AMOUNTS WEDNESDAY AND
WEDNESDAY NIGHT LOOK TO BE ABOUT 2-5 INCHES OVER THE PLAINS AND
3-9 INCHES OVER THE MOUNTAINS...WITH THE LOWER AMOUNTS IN THE
VALLEYS. TEMPERATURES WEDNESDAY NIGHT WILL LIKELY BE IN THE TEENS
OVER THE PLAINS TO SINGLE DIGITS OVER THE MOUNTAINS.
THE UPPER LOW WILL MOVE EAST OF THE AREA THURSDAY. SHOULD SEE
SNOW SLOWLY DIMINISHING OVER THE MOUNTAINS AND A CHANCE OF SNOW
CONTINUING OVER THE FAR EASTERN PLAINS...BUT SHOULD BE DONE BY
LATE AFTERNOON. TEMPERATURES WILL BE WARMING SLIGHTLY BUT WILL
STILL BE AROUND 20 TO 30 DEGREES BELOW NORMAL. FRIDAY WILL
CONTINUE THE WARMING AND DRYING TREND AS A WEAK UPPER RIDGE BUILDS
OVERHEAD.
SATURDAY THROUGH MONDAY WILL FEATURE A COUPLE DISTURBANCES IN THE
NORTHWEST FLOW ALOFT TO BRING A RETURN TO UNSETTLED WEATHER. WILL
SEE AN INCREASE IN THE CHANCES OF PRECIPITATION AGAIN FOR THE
AREA. TEMPERATURES WILL BE BACK TOWARD NORMAL....BUT STILL
SLIGHTLY BELOW AVERAGE. THEREFORE WILL EXPECT MORE RAIN FOR THE
PLAINS AND CONTINUED RAIN MIXED WITH SNOW FOR THE MOUNTAINS.
AVIATION...AREAS OF IFR/LIFR CEILINGS EXPECTED ACROSS THE FRONT
RANGE AIRPORTS THIS MORNING ALONG WITH A THREAT OF LIGHT FREEZING
DRIZZLE GIVEN TEMP/MOISTURE PROFILE IN PLACE. IF WE SEE ANY SNOW
WE DO NOT SEE ANY THREAT OF ACCUMULATION WITH ONLY FLURRIES
POSSIBLE. CEILING SHOULD GRADUALLY LIFT TODAY AT KDEN AND KAPA
WITH POSSIBLE EAST/SOUTHEAST WINDS GUSTING TO AROUND 25KTS. KBJC
WILL LIKELY SEE LOWER PREVAILING CONDITIONS ON BACK SIDE OF
CYCLONE. CHANCE THAT WINDS GO BACK TO NORTH OR NORTHWEST AT KAPA
AND KDEN THIS AFTERNOON DEPENDING ON INTENSITY OF DENVER CYCLONE
THAT DEVELOPS. BEST CHANCE OF SNOW WILL BE AFTER MIDNIGHT TONIGHT
AND MAINLY WEDNESDAY WHEN DEEPER UPSLOPE FLOW OCCURS. COULD SEE
ANOTHER 2-5 INCHES OF SNOW LATE TONIGHT/WEDNESDAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO MIDNIGHT MDT
WEDNESDAY NIGHT FOR COZ031-033-035.
&&
$$
SHORT TERM...D-L
LONG TERM....KRIEDERMAN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
839 PM EDT Wed Apr 17 2013
.NEAR TERM [Through Tonight]...
The primary concern over the CWA for the overnight hours continues
to be the potential for the development of Low clouds and/or Fog,
mainly after the fairly thick Upper level canopy exits to our east.
As of early this evening, the back edge of this Upper level cloud
shield has reached the western FL Panhandle and south-central AL,
and it is continuing to make steady progress to the east. That said,
the trends in the latest model guidance (from numerical to Hi-Res)
are starting to back off on the Fog Potential across the region,
while still favoring some Low Cigs over eastern portions of the CWA,
mainly towards morning. There is excellent agreement between the
NARRE and the HRRR on this solution, with other indicators in the
Nam, WRF, and numerical guidance from the GFS supporting this as
well. Sfc winds expected to remain in the 4-6 kt range are not
favorable for Fog.
Therefore, will trim back the patchy fog in the grids to focus on
the east, and will also tweak the sky grids to show greater low
level cloud cover to the east as well. Otherwise, the current fcst
is on track with only minor adjustments expected.
&&
.SHORT TERM [Thursday Through Friday Night]...
Short term weather concerns will remain dominated by strong upper
level trough ejecting across the central U.S. through Friday.
Associated surface cold front will make steady progress esewd across
the OH/MS River valleys but will likely slow as it enters our region
Friday. This will occur as most of the energy with the upper
system ejects northeast and mid/upper level flow begins to parallel
the surface front. Deep ascent and increasing moisture ahead of
this impulse will subsequently increase clouds with low clouds
tonight possibly lingering in many areas tomorrow as Gulf moisture
is pulled north-northwest. This will make high temperature
forecast a bit tricky for Thursday. However models still suggest
another mild day with highs reaching into the lower 80s for inland
sites and a few degrees cooler on Friday with more clouds and
increasing chance of showers from west to east.
Although this system will likely support a considerable severe
thunderstorm threat well to the northwest of our region, the potential
for severe weather appears fairly low into the tri-state area
Friday. Although an isolated storm could become marginally severe
given the abundant moisture and modest deep layer shear, with SPC
keeping low severe probabilities across the region. Regardless,
system will likely bring showers and thunderstorms starting in the
west Friday morning and spreading into the eastern areas by the
late afternoon.
&&
.LONG TERM [Saturday through Wednesday]...
Long term looks a bit unsettled early in the period as a surface
cold front stalls into northern/central FL. This could keep some
showers around south central GA and the eastern Big Bend Saturday
and possibly into Sunday. After a fairly cool day Saturday behind
the front with highs in the lower 70s, temperatures will return
to near normal (highs in the upper 70s/lower 80s) for Sunday and
slowly warm into the middle part of next week. Another mid/upper
level trough and associated surface front will approach the area
around mid week and bring another shot at showers and
thunderstorms by Wednesday.
&&
.AVIATION...
[Through 00z Friday] VFR conditions are expected to prevail for
the first part of tonight but quickly fall off as low ceilings
creep into KTLH, KVLD, and KABY around 09z. Confidence for wide
spread fog tonight is low in the western portions of our CWA with
the greatest chance for fog being in Valdosta. With winds not
dying off overnight only light fog is expected in our eastern
sites with low ceilings being the main concern. VFR conditions
will resume by mid-morning and continue throughout the rest of the
period.
&&
.MARINE...
South to southeasterly winds will increase tonight and tomorrow
ahead of an approaching weather system, with winds switching to
out of the west-northwest Friday into Saturday behind a cold
front. Speeds may approach advisory criteria just ahead of the
front and over western areas for several hours behind the front.
This system will bring an increasing chance of showers and
thunderstorms to the western legs early Friday and spread across
the area during the day. Although western areas should clear
Saturday, a chance of lingering showers should persist around the
Big Bend possibly into Sunday.
&&
.FIRE WEATHER...
Ample low level moisture on Thursday will keep minimum humidities
above critical levels. Abundant low-level moisture and rain are expected
on Friday with a passing cold front precluding any concerns. In
its wake, the airmass will dry out on Saturday but remain above
critical levels and this trend will continue into midweek.
&&
.HYDROLOGY...
Flooding is not expected to be a concern through the forecast
period, although a few sites will remain in `action stage`. We
could see an additional 0.50-1.00 inch of rain with the cold front
Friday and Saturday. However, this is not expected to result in any
significant rise over the next several days.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 64 83 64 80 54 / 0 10 10 60 60
Panama City 67 80 67 74 53 / 0 10 10 80 50
Dothan 63 86 65 73 47 / 0 10 20 80 40
Albany 63 85 64 78 49 / 0 10 10 70 60
Valdosta 63 83 64 81 56 / 0 10 10 50 60
Cross City 63 85 65 82 60 / 0 10 10 30 50
Apalachicola 67 78 68 76 55 / 0 10 10 60 50
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Gould
SHORT TERM...Evans
LONG TERM...Evans
AVIATION...Harrigan/Hersey
MARINE...Gould/Evans
FIRE WEATHER...Block
HYDROLOGY...Evans
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
212 PM EDT TUE APR 16 2013
.PREV DISCUSSION... /ISSUED 1147 AM EDT TUE APR 16 2013/
UPDATE...
HAVE MADE SEVERAL TWEAKS TO THE GRIDS. MAIN CHANGES HAVE BEEN TO
INCREASE DEWPOINTS AND POPS...ESPECIALLY FOR THIS AFTERNOON. ALL
HI-RES MODELS INDICATING AN INCREASE IN CONVECTIVE COVERAGE
BETWEEN 18-00Z. SURFACE DEWPOINTS ARE ACTUALLY QUITE A BIT HIGHER
THAN FORECAST. LIMITING FACTOR WILL BE CAPE IN THE MIDLEVELS...AS
NOTED ON THE 12Z KFFC SOUNDING WITH A WEAK WARM NOSE AT ABOUT
640MB. EVEN MODIFYING THIS WARM NOSE /DECREASE TO 1C INSTEAD OF
3C/ ONLY YIELDS ABOUT 500 J/KG SBCAPE. HOWEVER...WITH SUCH A
STRONG SHORTWAVE PUSHING INTO THE AREA AS EVIDENT ON WATER VAPOR
LOOPS...THE LIFTING MAY SERVE TO COOL THAT WARM NOSE FURTHER. KBMX
HAS A HINT OF THE WARM NOSE AND KOHX DOES NOT SHOW IT...SO WITH
THE WESTERLIES ALOFT ADVECTING THAT AIRMASS THIS WAY IT WILL BE A
MATTER OF THESE COMPETING FACTORS. SO THAT SAID...HAVE INCREASED
POPS FOR NOW TO CHANCE...THOUGH IF YOU BELIEVE THE HRRR POPS MAY
NEED TO BE INCREASED SOME MORE FOR THIS AFTERNOON...AND INCREASED
THUNDER WORDING TO CHANCE /SCATTERED/ AS WELL. NOT TOTALLY SOLD ON
THE HIGHER COVERAGE THAT THE HRRR IS INDICATING BUT AT LEAST HAVE
TRENDED IN THAT DIRECTION. UPDATED PRODUCTS WILL BE OUT SHORTLY.
TDP
PREV DISCUSSION... /ISSUED 735 AM EDT TUE APR 16 2013/
SHORT TERM /TODAY THROUGH WEDNESDAY/...
WEAK UPPER-LEVEL RIDGING PERSISTS OVER THE REGION THROUGH WEDNESDAY.
INFLUENCE OF THE RIDGE WILL LIKELY KEEP CHANCES FOR AFTERNOON
CONVECTION AT A MINIMUM TODAY ALTHOUGH INSTABILITY IS SUFFICIENT FOR
A MENTION OF A SLIGHT CHANCE OVER THE WESTERN THIRD TO HALF OF NORTH
AND CENTRAL GEORGIA. YESTERDAY EVENINGS SOUNDING SHOWS SIGNIFICANT
COOLING WOULD BE NEEDED IN THE 700-400MB LEVELS FOR ANY SIGNIFICANT
SEVERE WEATHER THREAT...AND THAT DOES NOT APPEAR TO BE LIKELY TODAY.
BY WEDNESDAY THE RIDGE AXIS IS SHIFTING EAST OF THE STATE ALLOWING
FOR CHANCE POPS OVER THE WEST AND SLIGHT CHANCE POPS TO SPREAD EAST
OVER THE REMAINDER OF THE FORECAST AREA. ALTHOUGH AN ISOLATED STRONG
STORM OR TWO CANNOT BE RULED OUT...INSTABILITY IS EXPECTED TO REMAIN
TOO MARGINAL FOR A MENTION OF SEVERE THUNDERSTORMS AT THIS TIME.
20
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
LONG TERM PERIOD BEGINS WITH DEVELOPING SOUTHERLY FLOW WHICH
SHOULD ACT TO SHUNT MOISTURE AXIS NORTH OF THE AREA. WILL STILL
CARRY RESIDUAL 20 POPS FOR THE NORTH INTO THE FIRST PART OF THE
OVERNIGHT PERIOD BUT QUICKLY DISSIPATE AFTER 06Z THU. ANOTHER
ROUND POSSIBLE THU BUT OVERALL TRENDS ARE FOR LESS DIURNAL
COVERAGE GIVEN SLIGHTLY LESS MOISTURE AND CORRESPONDINGLY LESS
INSTABILITY.
MODELS STILL IN GOOD AGREEMENT WITH EXCELLENT RUN TO RUN
CONSISTENCY WRT NEXT STORM SYSTEM WHICH LOOKS TO EJECT OUT OF THE
CENTRAL PLAINS THURSDAY AND MOVE INTO THE MID MISSISSIPPI VALLEY
THURSDAY NIGHT. TIMING FOR THE LOCAL AREA INDICATES BAND OF
SHOWERS AND SCATTERED THUNDERSTORMS REACHING NW GEORGIA JUST PRIOR
TO 12Z FRIDAY. INSTABILITY STILL LOOKS MARGINAL FOR THIS EVENT
WITH ONLY A NARROW SLIVER OF 200J/KG TO 400J/KG SURFACE BASED CAPE
TO WORK WITH FOR NORTHERN SECTIONS. SLIGHTLY MORE INSTABILITY TO
THE SOUTH WITH THIS SYSTEM AND WILL HAVE INCREASED THUNDER CHANCES
ROUGHLY FROM THE ATLANTA METRO SOUTHWARD. 850MB JET IS VERY
IMPRESSIVE WITH THIS SYSTEM WITH NEARLY 90 KTS INDICATED FOR THE
OHIO VALLEY. OUR AREA ONLY GETS THE SOUTHERN END OF THIS BUT STILL
GOOD ENOUGH FOR 65 KTS FOR NW CORNER. INSTABILITY LOOKS TO BE
AHEAD OF MAIN WIND CORE SO TIMING MAY NOT LINE UP FOR THIS ONE.
REGARDLESS...925MB WINDS ARE 50KTS OVER THE LOCAL AREA WHICH
SHOULD RESULT IN NEAR SEVERE WINDS EVEN WITH THE ABSENCE OF ROBUST
CONVECTION. WILL BEGIN TO RAMP UP WORDING IN HWO.
ONCE SYSTEM CLEARS...BENIGN BUT COLD CONDITIONS FOR THIS TIME OF
YEAR WITH LOWS RETURNING TO THE 30S.
DEESE
&&
.AVIATION...
18Z UPDATE...
VFR THIS AFTERNOON WITH SHRA OR POSSIBLE TSRA DEVELOPING MAINLY
FOR THE METRO TAFS...THOUGH WITH SOME QUESTIONS ABOUT COVERAGE
HAVE INCLUDED VCSH WITH A TEMPO TSRA. EXPECT THIS ACTIVITY TO
DIMINISH AFTER 00Z TONIGHT. CIGS SHOULD DROP AGAIN AFTER 08-09Z IN
THE MORNING...WITH SOME GUIDANCE HINTING AT IFR. HAVE INCLUDED LOW
MVFR FOR NOW BUT THIS WILL NEED TO BE REEVALUATED. MVFR FOG LIKELY
AT MOST SITES EXCEPT ATL AS WELL. EXPECT A LIFTING/CLEARING TREND
LATE WEDNESDAY MORNING. INCLUDED PROB30 TSRA FOR ATL WEDNESDAY
AFTERNOON. E TO SE WINDS GENERALLY 5-10KT THROUGH THE PERIOD
EXCEPT LIGHTER OVERNIGHT.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON OCCURRENCE OF TSRA THIS AFTERNOON...LOW ON IMPACTS TO ATL.
MEDIUM ON CIGS WEDNESDAY MORNING.
HIGH ON ALL OTHER ELEMENTS.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 79 59 82 59 / 20 10 30 20
ATLANTA 78 63 81 62 / 40 20 30 20
BLAIRSVILLE 76 57 77 58 / 30 20 40 20
CARTERSVILLE 81 60 82 59 / 40 20 30 20
COLUMBUS 83 64 85 63 / 20 10 20 20
GAINESVILLE 78 61 80 61 / 30 20 30 20
MACON 82 59 83 58 / 20 5 20 10
ROME 81 60 82 60 / 40 20 30 20
PEACHTREE CITY 78 59 82 60 / 40 20 30 20
VIDALIA 81 62 83 62 / 5 0 10 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1147 AM EDT TUE APR 16 2013
.UPDATE...
HAVE MADE SEVERAL TWEAKS TO THE GRIDS. MAIN CHANGES HAVE BEEN TO
INCREASE DEWPOINTS AND POPS...ESPECIALLY FOR THIS AFTERNOON. ALL
HI-RES MODELS INDICATING AN INCREASE IN CONVECTIVE COVERAGE
BETWEEN 18-00Z. SURFACE DEWPOINTS ARE ACTUALLY QUITE A BIT HIGHER
THAN FORECAST. LIMITING FACTOR WILL BE CAPE IN THE MIDLEVELS...AS
NOTED ON THE 12Z KFFC SOUNDING WITH A WEAK WARM NOSE AT ABOUT
640MB. EVEN MODIFYING THIS WARM NOSE /DECREASE TO 1C INSTEAD OF
3C/ ONLY YIELDS ABOUT 500 J/KG SBCAPE. HOWEVER...WITH SUCH A
STRONG SHORTWAVE PUSHING INTO THE AREA AS EVIDENT ON WATER VAPOR
LOOPS...THE LIFTING MAY SERVE TO COOL THAT WARM NOSE FURTHER. KBMX
HAS A HINT OF THE WARM NOSE AND KOHX DOES NOT SHOW IT...SO WITH
THE WESTERLIES ALOFT ADVECTING THAT AIRMASS THIS WAY IT WILL BE A
MATTER OF THESE COMPETING FACTORS. SO THAT SAID...HAVE INCREASED
POPS FOR NOW TO CHANCE...THOUGH IF YOU BELIEVE THE HRRR POPS MAY
NEED TO BE INCREASED SOME MORE FOR THIS AFTERNOON...AND INCREASED
THUNDER WORDING TO CHANCE /SCATTERED/ AS WELL. NOT TOTALLY SOLD ON
THE HIGHER COVERAGE THAT THE HRRR IS INDICATING BUT AT LEAST HAVE
TRENDED IN THAT DIRECTION. UPDATED PRODUCTS WILL BE OUT SHORTLY.
TDP
&&
.PREV DISCUSSION... /ISSUED 735 AM EDT TUE APR 16 2013/
SHORT TERM /TODAY THROUGH WEDNESDAY/...
WEAK UPPER-LEVEL RIDGING PERSISTS OVER THE REGION THROUGH WEDNESDAY.
INFLUENCE OF THE RIDGE WILL LIKELY KEEP CHANCES FOR AFTERNOON
CONVECTION AT A MINIMUM TODAY ALTHOUGH INSTABILITY IS SUFFICIENT FOR
A MENTION OF A SLIGHT CHANCE OVER THE WESTERN THIRD TO HALF OF NORTH
AND CENTRAL GEORGIA. YESTERDAY EVENINGS SOUNDING SHOWS SIGNIFICANT
COOLING WOULD BE NEEDED IN THE 700-400MB LEVELS FOR ANY SIGNIFICANT
SEVERE WEATHER THREAT...AND THAT DOES NOT APPEAR TO BE LIKELY TODAY.
BY WEDNESDAY THE RIDGE AXIS IS SHIFTING EAST OF THE STATE ALLOWING
FOR CHANCE POPS OVER THE WEST AND SLIGHT CHANCE POPS TO SPREAD EAST
OVER THE REMAINDER OF THE FORECAST AREA. ALTHOUGH AN ISOLATED STRONG
STORM OR TWO CANNOT BE RULED OUT...INSTABILITY IS EXPECTED TO REMAIN
TOO MARGINAL FOR A MENTION OF SEVERE THUNDERSTORMS AT THIS TIME.
20
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
LONG TERM PERIOD BEGINS WITH DEVELOPING SOUTHERLY FLOW WHICH
SHOULD ACT TO SHUNT MOISTURE AXIS NORTH OF THE AREA. WILL STILL
CARRY RESIDUAL 20 POPS FOR THE NORTH INTO THE FIRST PART OF THE
OVERNIGHT PERIOD BUT QUICKLY DISSIPATE AFTER 06Z THU. ANOTHER
ROUND POSSIBLE THU BUT OVERALL TRENDS ARE FOR LESS DIURNAL
COVERAGE GIVEN SLIGHTLY LESS MOISTURE AND CORRESPONDINGLY LESS
INSTABILITY.
MODELS STILL IN GOOD AGREEMENT WITH EXCELLENT RUN TO RUN
CONSISTENCY WRT NEXT STORM SYSTEM WHICH LOOKS TO EJECT OUT OF THE
CENTRAL PLAINS THURSDAY AND MOVE INTO THE MID MISSISSIPPI VALLEY
THURSDAY NIGHT. TIMING FOR THE LOCAL AREA INDICATES BAND OF
SHOWERS AND SCATTERED THUNDERSTORMS REACHING NW GEORGIA JUST PRIOR
TO 12Z FRIDAY. INSTABILITY STILL LOOKS MARGINAL FOR THIS EVENT
WITH ONLY A NARROW SLIVER OF 200J/KG TO 400J/KG SURFACE BASED CAPE
TO WORK WITH FOR NORTHERN SECTIONS. SLIGHTLY MORE INSTABILITY TO
THE SOUTH WITH THIS SYSTEM AND WILL HAVE INCREASED THUNDER CHANCES
ROUGHLY FROM THE ATLANTA METRO SOUTHWARD. 850MB JET IS VERY
IMPRESSIVE WITH THIS SYSTEM WITH NEARLY 90 KTS INDICATED FOR THE
OHIO VALLEY. OUR AREA ONLY GETS THE SOUTHERN END OF THIS BUT STILL
GOOD ENOUGH FOR 65 KTS FOR NW CORNER. INSTABILITY LOOKS TO BE
AHEAD OF MAIN WIND CORE SO TIMING MAY NOT LINE UP FOR THIS ONE.
REGARDLESS...925MB WINDS ARE 50KTS OVER THE LOCAL AREA WHICH
SHOULD RESULT IN NEAR SEVERE WINDS EVEN WITH THE ABSENCE OF ROBUST
CONVECTION. WILL BEGIN TO RAMP UP WORDING IN HWO.
ONCE SYSTEM CLEARS...BENIGN BUT COLD CONDITIONS FOR THIS TIME OF
YEAR WITH LOWS RETURNING TO THE 30S.
DEESE
AVIATION...
12Z UPDATE...
MAINLY IFR CONDITIONS PREVAILING ACROSS THE FORECAST AREA AT THIS
TIME. I EXPECT IFR...WITH LOCAL LIFR...CEILINGS AND VISIBILITIES TO
LAST THROUGH 14Z...IMPROVING TO MOSTLY MVFR CONDITIONS ACROSS THE
AREA 14-19Z WITH VFR EXPECTED AFTER. ISOLATED SHOWERS AND
THUNDERSTORMS ARE POSSIBLE ACROSS THE WESTERN HALF OF THE FORECAST
AREA THIS AFTERNOON...BUT PROBABILITIES AT TAF SITES TOO LOW TO
INCLUDE IN THE TAFS AT THIS TIME. WINDS WILL REMAIN EAST TO
SOUTHEAST THROUGH THE FORECAST PERIOD. WINDS SPEEDS WILL REMAIN 6KT
OR LESS THROUGH 14Z...INCREASING INTO THE 6-9KT RANGE THROUGH 22Z
BEFORE DIMINISHING TO 6KT OR LESS AGAIN.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON TIMING OF CIGS/VIS TRENDS THIS MORNING.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 79 59 80 60 / 20 10 30 20
ATLANTA 78 63 80 62 / 40 20 30 20
BLAIRSVILLE 76 57 78 59 / 30 20 30 20
CARTERSVILLE 81 59 81 60 / 40 20 30 20
COLUMBUS 83 64 83 63 / 20 10 20 20
GAINESVILLE 78 62 80 61 / 30 20 30 20
MACON 82 61 82 61 / 20 5 20 20
ROME 81 59 81 61 / 40 20 30 20
PEACHTREE CITY 78 58 81 58 / 40 20 30 20
VIDALIA 81 62 83 63 / 5 0 10 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
935 PM CDT WED APR 17 2013
.DISCUSSION...
934 PM CDT
EVENING/MESOSCALE UPDATE...
HAVE CANCELLED REMAINING CONVECTIVE WATCHES...THOUGH FLOODING WILL
CONTINUE TO BE A SIGNIFICANT ISSUE THROUGH THURSDAY AND BEYOND.
WARM FRONT EXTENDS FROM LOW PRESSURE WAVE OVER WESTERN MISSOURI...
NORTHEAST INTO CENTRAL ILLINOIS AND CENTRAL INDIANA AT 02Z. OUTFLOW
FROM PERSISTENT ELEVATED THUNDERSTORMS ACROSS IA/NORTHERN IL/IN HAS
CONTINUED TO SUPPRESS SURFACE WARM FRONT SOUTH OF THE CWA...AND WILL
LIKELY CONTINUE TO DO SO OVERNIGHT BEFORE DEEPENING SURFACE LOW
LIFTS FROM MISSOURI INTO NORTHWEST IL IN ASSOCIATION WITH SHORT WAVE
LIFTING OUT OF BASE OF UPPER TROUGH OVER THE SOUTHERN PLAINS.
UNFORTUNATELY...THIS WILL RESULT IN CONTINUED FORCED ASCENT ATOP
CONVECTIVELY ENHANCED FRONTAL ZONE TONIGHT WITHIN A BROAD REGION OF
PERSISTENT STRONG WARM/MOIST ADVECTION AHEAD OF DEEP UPPER TROUGH
OVER THE PLAINS.
ILX 00Z SOUNDING TELLS THE STORY WITH RESPECT TO THE DIMINISHED
SEVERE THREAT WITH STRONG LOW LEVEL INVERSION NORTH OF FRONT
PREVENTING NEAR SFC-BASED STORMS. RAP GUIDANCE CONTINUES TO DEPICT A
GRADIENT IN THE MUCAPE FIELD INCREASING TO 500-1000 J/KG AS YOU MOVE
FARTHER SOUTH OF I-80. WHILE EFFECTIVE BULK SHEAR IN EXCESS OF 60 KT
WILL CONTINUE TO ALLOW SOME ORGANIZATION FOR ELEVATED CONVECTION
NORTH OF WARM FRONT...THE THREAT OF SEVERE WEATHER SHOULD BE
LIMITED TO MARGINAL HAIL WITH THE BETTER ORGANIZED STORMS.
WHILE THE SEVERE THREAT INTO THE OVERNIGHT HOURS IS RATHER LOW...
FLOODING THREAT CONTINUES TO BE SIGNIFICANT INTO THURSDAY. RADAR
ESTIMATES AND OBSERVED RAINFALL REPORTS INDICATE THAT MOST AREAS
HAVE SEEN UPWARDS OF 0.75 INCHES OF RAIN...WITH MANY AREAS BETWEEN
1.5 AND 2.0 INCHES AND PARTS OF NORTH CENTRAL ILLINOIS IN EXCESS OF
2.5 INCHES. ILX 00Z RAOB DEPICTS PWAT OF 1.38 INCHES...199 PERCENT
OF NORMAL...AN INDICATION OF THE VERY MOIST AIR MASS. ADDITIONAL
RAINFALL AMOUNTS IN THE 1-2 INCH RANGE ARE VERY LIKELY THROUGH
THURSDAY...LIKELY LEADING TO EXTENSIVE FLOODING ON AREA STREAMS AND
RIVERS. AERIAL FLOOD WARNINGS REMAIN IN EFFECT INTO MIDDAY
THURSDAY...AND MANY RIVER FORECAST SITES ARE HEADED FOR MODERATE TO
MAJOR FLOODING.
RATZER
&&
.PREV DISCUSSION...
342 PM CDT
.SHORT TERM...THROUGH FRIDAY...
HAZARDOUS WEATHER ISSUES FROM SEVERE THUNDERSTORMS TO EXCESSIVE
RAINFALL TO TORNADIC POTENTIAL WILL IMPACT THE REGION THROUGH
THURSDAY NIGHT.
FOR THE REMAINDER OF THE AFTERNOON AND INTO THIS EVENING...AT 230PM
CDT...STRONG THUNDERSTORMS EXTEND ALONG A LINE FROM NEAR
WAUKEGAN...SOUTHWEST THROUGH OTTAWA. WEST OF THIS LINE...AN
EXTENSIVE AREA OF OVERRUNNING PCPN WITH EMBEDDED THUNDER EXTENDED
BACK THROUGH ERN IOWA AND MISSOURI. MUCH OF THE ACTIVITY OVER NRN
IL HAS FORMED ALONG AN ELEVATED WARM FRONT...BUT A MORE SOLID LINE
HAS DEVELOPED IN THE WARM SECTOR. EXPECT THAT THE THUNDERSTORMS
WILL SAG SEWD THROUGH THE EVENING...BRINGING SHOWERS AND
THUNDERSTORMS INTO EAST-CENTRAL ILLINOIS AND NORTHWESTERN INDIANA.
WITH COPIOUS AMOUNTS OF MOISTURE STREAMING INTO THE REGION...THE
STORMS HAVE BEEN VERY EFFICIENT RAIN PRODUCERS...WITH 0.81 INCHES OF
RAIN MEASURED AT THE ROCKFORD AIRPORT BTWN 12-18Z THIS MORNING.
STORMS HAVE ALSO BEEN MARGINALLY SEVERE WITH NUMEROUS REPORTS OF
SMALL HAIL RECEIVED...AND A FEW REPORTS OF LARGER HAIL AS WELL.
THIS WILL BE THE CONVECTIVE MODE FOR THE REMAINDER OF THE EVENING
AND OVERNIGHT TONIGHT...WITH MODERATE TO HEAVY RAIN AND SMALL HAIL
AND OCCASIONAL STRONG WINDS GUSTS.
THE FLOODING AND SEVERE WEATHER POTENTIAL WILL RAMP UP EVEN FURTHER
TOMORROW AS THE UPPER TROUGH MOVES OUT OVER THE CENTRAL PLAINS AND A
SFC LOW DEEPENS. THE SFC LOW WILL SWING THROUGH THE SOUTH HIGH
PLAINS EARLY THIS EVENING BEFORE TURNING NEWD...RIPPLING ALONG A
QUASI-STATIONARY COLD FRONT AND WARM FRONT. BY THURSDAY
MORNING...THE LOW WILL ELONGATE FROM NWRN IL THROUGH NWRN MO...WITH
THE SFC WARM FRONT EXTENDING NEWD ACROSS CENTRAL LAKE MICHIGAN.
THIS WILL PUT THE CWA FIRMLY IN THE WARM SECTOR. WITH A WIDE OPEN
GLFMEX...DEEP LAYER MOISTURE WILL STREAM NWD INTO THE REGION...WITH
PWATS EXCEEDING 1.5 INCHES FOR AN EXTENDED PERIOD OF TIME...LEADING
TO THE POTENTIAL FOR SIGNIFICANT WIDESPREAD RIVER AND AREAL
FLOODING. SEE THE HYDROLOGY SECTION FOR FURTHER DETAILS.
THE SEVERE WEATHER MODE SHOULD FOCUS ON STRONG...DAMAGING WINDS AND
POSSIBLE TORNADOES. THE LATEST SPC DAY 2 CONVECTIVE OUTLOOK HAS
INCREASED THE AREA SOUTH OF A LINE FROM EVANSTON TO PONTIAC TO A
MODERATE RISK...WITH THE REMAINDER OF THE AREA IN A SLIGHT RISK.
INCREASING HEAT AND MOISTURE...TEMPERATURES REACHING INTO THE LOW TO
MIDDLE 70S AND DEW POINTS IN THE LOW TO MIDDLE 60S IN THE WARM
SECTOR...INSTABILITY WILL BE AMPLE. WHILE THE GENERAL CONVECTIVE
MODE WILL BE LINEAR WITH SMALL LINES AND BOWS POSSIBLE...PRODUCING
DAMAGING WINDS...THE MODEL GUIDANCE IS IN GOOD AGREEMENT ON A STRONG
LOW LEVEL JET...WITH SWLY WINDS OF 55-65KT ACROSS THE REGION. WHILE
SFC WINDS ARE GENERALLY PROGGED TO BE SOUTHERLY...THERE WILL BE
OPPORTUNITY FOR SFC WINDS TO BACK A LITTLE MORE EAST OF SOUTH AS THE
SFC LOW TRACKS THROUGH NWRN IL AND INTO SRN WI. GIVEN THE AMPLE
INSTABILITY...COMBINED WITH CLOCKWISE TURNING HODOGRAPHS...DISCRETE
SUPER CELLS MAY DEVELOP OUT IN THE WARM SECTOR AHEAD OF THE LINEAR
CONVECTION...WHICH WOULD BRING THE TORNADIC POTENTIAL TO THE
REGION.
THE POTENTIAL FOR SEVERE WEATHER AND HEAVY RAINFALL WILL CONTINUE
UNTIL THE ASSOCIATED COLD FRONT PUSHES THROUGH THE REGION...BRINGING
IN MUCH COOLER AIR. THE GUIDANCE IS IN GOOD AGREEMENT ON PUSHING
THE FRONT ACROSS THE AREA THURSDAY EVENING. AS THE SFC LOW PUSHES
OFF TO THE NORTHEAST...THE UPPER TROUGH WILL ALSO CROSS THE AREA.
WITH PLENTY OF RESIDUAL SFC MOISTURE AND COOLER AIR AND CYCLONIC
CURVATURE ALOFT...SOME LINGERING INSTABILITY SHOWERS SHOULD PERSIST
INTO FRIDAY. HIGHS ON FRIDAY SHOULD DROP BACK INTO THE MIDDLE TO
UPPER 40S.
KREIN
.LONG TERM - SATURDAY THROUGH WEDNESDAY...
SPRAWLING SURFACE HIGH PRESSURE TO BUILD INTO THE AREA SATURDAY
BEHIND DEPARTING SURFACE LOW/UPPER LEVEL TROUGH. A RETURN TO
UNSEASONABLY COOL TEMPS WITH A NEEDED BREAK IN PRECIPITATION WILL BE
SHORT LIVED HOWEVER AS THE UPPER FLOW QUICKLY RETURNS SOUTHWESTERLY
AS ANOTHER POWERFUL SHORTWAVE TROUGH DIGS INTO WESTERN NORTH AMERICA
ON SUNDAY. THIS SHORTWAVE CARVES OUT A TROUGH ACROSS THE MOUNTAIN
WEST SUNDAY NIGHT INTO MONDAY.
A SERIES OF UPPER LEVEL SHORT WAVE TROUGHS WILL THEN RIPPLE
NORTHEAST IN THE SW FLOW ALOFT. SPECIFIC FEATURES ARE POORLY
RESOLVED BY MEDIUM RANGE MODELS BUT OVERALL TREND WILL BE A RETURN
TO INCREASING MOISTURE AS GULF OPENS BACK UP AGAIN. MEDIUM RANGE
MODELS ARE IN FAIRLY GOOD AGREEMENT IN CONCEPT IN SAGGING THE
SURFACE FRONTAL BOUNDARY SOUTH ACROSS THE LOCAL AREA MONDAY NIGHT
AND STALLING IT OUT TUESDAY SETTING THE STAGE FOR ANOTHER PROLONGED
PERIOD OF WET WEATHER TUESDAY INTO WEDNESDAY AS RIPPLES OF LOW
PRESSURE LIFT NORTHEAST ALONG THE BOUNDARY.
EF
&&
.HYDROLOGY...
350 PM CDT
WITH SFC DEW POINTS EXPECTED TO REACH INTO THE LOWER TO MIDDLE 60S
AND PWATS POSSIBLY REACHING AS HIGH AS 1.75 INCHES...ANY
THUNDERSTORMS THAT DEVELOP WILL BE EFFICIENT RAIN PRODUCERS. BASED
ON THE MATT BUNKERS PWAT CLIMATOLOGY...THESE VALUES APPROACH
RECORD LEVELS. SO...FLOODING WILL BE A MAJOR CONCERN FOR THE
ENTIRE CWA...WITH STORM TOTAL PCPN AMOUNTS OF 2-3 INCHES OVER THE
SERN PORTIONS OF THE CWA...GENERALLY SOUTH OF I-80...AND 3-4
INCHES TO THE NORTH. LATEST LOCAL QPF WOULD SUGGEST AN AREA OF
PCPN OF 4-5 INCHES IS POSSIBLE ALONG OVER NORTHERN ILLINOIS. THIS
REPRESENTS AN INCREASE OVER PREVIOUS FORECASTS...BUT GIVEN THE
RECORD LEVEL PWATS FOR AN EXTENDED PERIOD OF TIME...CONFIDENCE IS
INCREASING FOR THIS SIGNIFICANT RAINFALL. WITH MANY RIVERS AND
STREAMS ARE ALREADY NEAR OR ABOVE MINOR FLOOD STAGE...THIS AMOUNT
OF RAIN WILL BRING ADDITIONAL RISES TO MODERATE AND MAJOR FLOOD
LEVEL. IN ADDITION TO RIVER FLOODING...AREAL FLOODING OR
RURAL...SUBURBAN AND URBAN AREAS IS LIKELY...WITH LOW LYING ROADS
AND VIADUCTS FLOODING...AS WELL AS...ROADSIDE DRAINAGE DITCHES AND
DRAINAGE PONDS EXCEEDING CAPACITY. AREAS NOT SEEING FLOODING WILL
AT LEAST SEE AREAS OF STANDING OR PONDING WATER ON ROADS.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* WIDESPREAD LIGHT TO OCCASIONAL MODERATE RAIN FIRST PART OF
EVENING WITH A FEW EMBEDDED TS AND LOCALIZED HEAVY RAIN.
* WIDESPREAD RAIN CONTINUES LATE EVENING INTO OVERNIGHT WITH MORE
NUMEROUS TS AND MORE WIDESPREAD AREAS OF +RA.
* WIDESPREAD MVFR WITH AREAS IFR TO START OUT THE EVE THEN IFR TO
BECOME PREVAILING AS RA AND TS COVERAGE INCREASES FOR LATER EVE
AND OVERNIGHT.
* ENE SFC WINDS TO GRADUALLY BECOME SSE AND BECOMING MODERATELY
GUSTY BY DAYBREAK AND INCREASINGLY GUSTY FROM SSE-SSW WINDS
DURING THE DAY.
TRS
//DISCUSSION...UPDATED 00Z...
MULTIPLE SHORT WAVES CONTINUE/TO CONTINUE TO MOVE FROM THE
SOUTHERN PLAINS NORTHEASTWARD ACROSS THE MID MO AND MID AND UPPER
MS VALLEYS TO THE WESTERN GREAT LAKES TONIGHT AND THU AS THE
UPPER UPPER TROUGH CONTINUE TO MOVE E FROM THE ROCKIES AND OVER
THE PLAINS.
THESE MULTIPLE SMALL TO MEDIUM DISTURBANCES ARE EXPECTED TO
CONTINUE TO PERIODICALLY CAUSE INCREASED RA COVERAGE AND NUMBER
OF TS OVER THE CHI TERMINALS ALONG AND N OF THE SURFACE BOUNDARY
TONIGHT AS THEY LIFT NE TOWARD AN THEN OVER THE LOCAL AREA.
PROFILER...VAD AND RAOB WIND MEASUREMENTS CONFIRM INCREASING S TO
SW FLOW ABOVE THE INCREASINGLY SHALLOW BOUNDARY LAYER WITH SPEED
OF 50 TO 60KT WITHIN 1 TO 2K FT OF SURFACE BY LATE OVERNIGHT
TONIGHT AND HAVE CONTINUED LLWS FORECASTS DURING THE NIGHT IN 00Z
SET OF TAFORS.
MVFR AND AREAS OF IFR CEILINGS EXPECTED TO PERSIST N OF THE
SURFACE FRONT TIL IT LIFTS NORTHWARD AND ACROSS THE LOCAL
TERMINALS DURING THE PREDAWN TO EARLY MORNING HOURS OF THU. WITH
THE WARM FRONT TO THE N OF THE LOCAL AREA BY EARLY THU MORNING THE
STRONGEST FORCING RESULTING FROM THE VERY STRONG LOW LEVEL WAA AND
CONVERGENCE IS ANTICIPATED TO SHIFT GENERALLY TO THE N OF THE
LOCAL TERMINALS THOUGH ACROSS THE LOCAL AREA S OF THE BOUNDARY
SURFACE BASED INSTABILITY WILL BE INCREASING DURING THU SO CANNOT
RULE OUT SCATTERED TSRA FROM MID AFTERNOON INTO EARLY EVENING.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN FORECAST WIND TRENDS.
* MODERATE CONFIDENCE IN TIMING OF BETTER TIME FRAMES FOR MORE
WIDESPREAD RA AND +RA/+TSRA.
* LOW CONFIDENCE IN ONSET AND DURATION OF IFR CONDITIONS.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...VFR...CHANCE SHRA WITH LOCAL MVFR.
SATURDAY...VFR...LAKE BREEZE DEVELOPING AND REACHING CHI TERMINALS
EARLY-MID AFTERNOON.
SUNDAY...VFR...SLIGHT CHANCE SHRA.
MONDAY...VFR...CHANCE SHOWERS.
TUESDAY...MVFR LOWERING TO IFR....CHANCE OF SHOWERS.
TRS
&&
.MARINE...
420 PM CDT
A PAIR OF LOW PRESSURE CENTERS OVER NORTHERN MISSOURI AND THE
TEXAS PANHANDLE WILL MOVE NORTHEAST TONIGHT AND THURSDAY AND
OVERSPREAD THE GREAT LAKES AREA. A BRIEF PERIOD OF OCCASIONALLY
GALE FORCE GUSTS WILL OCCUR ACROSS SOUTHERN LAKE MICHIGAN
THURSDAY AS THE SURFACE PRESSURE GRADIENT INTENSIFIES SOUTH OF THE
ELONGATED LOW PRESSURE AREA FROM THE SAULT TO GREEN BAY.
AS LOW PRESSURE LOCATES NEAR MILWAUKEE THURSDAY EVENING AND THEN
MOVES NORTHEAST TO THE STRAITS OF MACKINAC BY DAYBREAK FRIDAY... A
POWERFUL COLD FRONT WILL SURGE EAST ACROSS THE LAKE WITH WINDS
INCREASING RAPIDLY BEHIND THE FRONT DURING THE PREDAWN HOURS
FRIDAY. WINDS WILL RAPIDLY REACH GALE FORCE TO 45 KTS FRIDAY WITH
A DIMINISHING TREND BEGINNING AFTER DARK FRIDAY EVENING. SURFACE
HIGH PRESSURE WILL BUILD INTO THE AREA SATURDAY BRINGING A PERIOD
OF LIGHT WINDS LASTING ONLY UNTIL DAYBREAK SUNDAY WHEN SOUTHERLY
FLOW WILL AGAIN INCREASE AHEAD OF AN APPROACHING FRONTAL BOUNDARY.
ED F
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 7 AM FRIDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 AM
FRIDAY.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 AM FRIDAY TO 4 AM
SATURDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742...7 AM THURSDAY TO 7 PM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 7 AM THURSDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...7 AM THURSDAY TO 10 PM
THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1228 PM CDT TUE APR 16 2013
.DISCUSSION...
ISSUED 1030 AM CDT TUE APR 16 2013
COLD FRONT HAS PUSHED JUST SOUTH OF OUR CWA...BUT WAS CLOSE ENOUGH
TO LAWRENCEVILLE THAT TEMPERATURES THERE ARE STILL IN THE MID 60S.
MOSTLY SEEING 40S ELSEWHERE WITH SOME LOWER 50S. ELEVATED
CONVECTION NORTH OF THE BOUNDARY HAS BEEN INCREASING OVER CENTRAL
ILLINOIS AS IT MOVES OUT OF MISSOURI...AND COVERED MOST OF THE
CWA AT 1030 AM EXCEPT FOR THE FAR NORTHWEST AND FAR SOUTHEAST.
LATEST RAP MODEL SHOWING THE SCATTERED CONVECTION CONTINUING
ACROSS MUCH OF THE CWA INTO THIS AFTERNOON...WITH LESS COVERAGE
NORTHWEST OF THE ILLINOIS RIVER. HAVE SENT OUT SOME ZONE/GRID
UPDATES TO INCREASE THE RAIN CHANCES TODAY...WITH SOME MINOR
ADJUSTMENTS TO TEMPERATURES REQUIRED AS WELL.
GEELHART
&&
.HYDROLOGY...
ISSUED 1030 AM CDT TUE APR 16 2013
EARLY LOOK AT 12Z MODEL RUNS CONTINUE TO SUPPORT AN INCREASING
POOL OF MOISTURE INTO ILLINOIS ON WEDNESDAY...WITH PRECIPITABLE
WATER VALUES UP TO AROUND 1.5 TO 1.6 INCHES BY LATE WEDNESDAY
AFTERNOON...WHICH IS ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL.
BULK OF THE HEAVIEST RAIN EXPECTED WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. LATEST QPF FORECAST SHOWS OVER 3 INCHES ACROSS A
LARGE PART OF THE FORECAST AREA THROUGH FRIDAY...WITH 2-3 INCHES
ACROSS ABOUT THE SOUTHEAST THIRD. PROBABILITY FORECASTS FROM THE
WEATHER PREDICTION CENTER SHOW A 50-60 PERCENT CHANCE OF RECEIVING
AT LEAST 2.5 INCHES OF RAIN FROM WEDNESDAY EVENING THROUGH
THURSDAY EVENING.
CURRENTLY ONLY THE ILLINOIS RIVER AT HAVANA AND BEARDSTOWN ARE IN
FLOOD...BUT MORE FLOODING IS EXPECTED ACROSS MANY RIVERS. STANDARD
RIVER FORECASTS ONLY ACCOUNT FOR 24-HOUR QPF...BUT RFC CONTINGENCY
FORECASTS BASED ON 72-HOUR QPF SHOW POTENTIAL FOR MODERATE OR
MAJOR FLOODING IN SOME CASES.
HAVE SENT OUT A HYDROLOGIC OUTLOOK TO ADDRESS THE HEAVY RAIN
POTENTIAL...WHILE REMAINING MODEL GUIDANCE IS DIGESTED TO
DETERMINE THE POTENTIAL FOR ANY FLOOD WATCHES WITH THE AFTERNOON
FORECAST PACKAGE.
GEELHART
&&
.AVIATION...
ISSUED 1224 PM CDT TUE APR 16 2013
BAND OF THUNDERSTORMS WILL CONTINUE TO AFFECT KCMI AND KDEC FOR
ANOTHER HOUR OR TWO...WITH MVFR CEILINGS/VISIBILITIES. GENERAL
TREND OTHERWISE WILL BE FOR SCATTERED SHOWERS TO CONTINUE THIS
AFTERNOON...WITH CEILINGS GENERALLY VFR FOR A TIME. HOWEVER...
ADDITIONAL CONVECTIVE DEVELOPMENT WILL BRING MVFR CONDITIONS AGAIN
THIS EVENING. BASED ON SOUNDINGS...CEILINGS AFTER 06Z MAY FALL TO
AROUND 1000 FEET OR SO...WHICH WILL LINGER A GOOD PART OF
WEDNESDAY MORNING. HOWEVER...A WARM FRONT WILL LIFT NORTHWARD
ACROSS THE TAF SITES TOWARD LATE MORNING...RAPIDLY LIFTING
CEILINGS BACK INTO VFR RANGE.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 330 AM CDT TUE APR 16 2013
VERY UNSETTLED WEATHER PATTERN TO OCCUR THROUGH FRIDAY ACROSS
CENTRAL AND SE IL WITH PERIODS OF SHOWERS AND THUNDERSTORM GIVING
2-4 INCHES OF RAIN BY FRIDAY WITH THE HEAVIEST AMOUNTS FROM I-55 NW.
SPC ALSO CONTINUES SLIGHT RISK OF SEVERE STORMS ACROSS AREAS WEST OF
I-57 WED NIGHT AND ACROSS MUCH OF REGION THU/THU EVENING. LIKE
YESTERDAYS MODEL RUNS...THE 00Z MODEL SUITE TODAY CONTINUES SLOWER
TREND WITH POTENT COLD FRONT MOVING EASTWARD ACROSS IL THU
AFTERNOON/EVENING.
SHORT TERM...TODAY THROUGH FRIDAY
MCS FROM CENTRAL MO NE ACROSS CENTRAL IL INTO NW INDIANA HAS
GRADUALLY BEEN WEAKENING THE PAST HOUR OR SO. A BROKEN LINE OF
THUNDERSTORMS WITH HEAVY RAINS WAS ALONG SE EDGE OF THIS MCS FROM
TAYLORVILLE AND SHELBYVILLE TO TUSCOLA AND CHRISMAN. HAD A FEW
REPORTS OF HAIL BETWEEN MIDNIGHT AND 1 AM OVER PARTS OF SANGAMON AND
LOGAN COUNTIES. COLD FRONT HAD SAGGED SLOWLY INTO SE IL...SE OF
I-70 EARLY THIS MORNING BEING PULLED SE BY MCS AND 1012 MB LOW
PRESSURE NEAR INDY. COLD FRONT EXTENDED SW TO A 1000 MB LOW
PRESSURE OVER EASTERN NM. BROAD SW UPPER LEVEL FLOW OVER THE
COUNTRY HAS BEEN SLOWLY DOWN THE SE PROGRESSION OF THIS COLD FRONT.
RADAR ESTIMATED 1.5-2.5 INCHES OF RAIN ALONG AND JUST SE OF A
RUSHVILLE TO BLOOMINGTON LINE.
CONVECTION TO CONTINUE TO WEAKEN DURING THE MORNING WITH AS LOW
LEVEL JET THAT PEAKED AROUND 40 KTS WEAKENS. BEST CHANCES OF
SHOWERS AND THUNDERSTORMS TODAY SHIFTS INTO SE IL CLOSER TO
FRONTAL BOUNDARY WHICH CONTINUES TO SLOWLY SAG SOUTHWARD TODAY...
WHILE DRIER AND COOLER TO THE NORTH. SCATTERED SHOWERS AND
THUNDERSTORMS POSSIBLE THIS AFTERNOON ESPECIALLY FROM I-72 SOUTH.
HIGHS TODAY RANGE FROM THE MID 50S OVER THE IL RIVER VALLEY FROM
I-55 NW TO THE UPPER 60S TO NEAR 70F IN FAR SE IL ALONG HIGHWAY
50.
INCREASING LOW LEVEL JET TO INCREASE CHANCES OF SHOWERS AND
THUNDERSTORMS TONIGHT ESPECIALLY OVERNIGHT WHEN SPC HAS SLIGHT
CHANCE OF SEVERE OVER SE IL AND SW OF SPRINGFIELD. MAINLY A HAIL
THREAT SW OF SPRINGFIELD WHILE HAIL AND WIND IN FAR SE IL NEAR
HIGHWAY 50.
FRONTAL BOUNDARY TO BEGIN TO LIFT BACK NORTHWARD OVER CENTRAL IL
WED WITH SHOWERS AND THUNDERSTORMS LIKELY ESPECIALLY NW AREAS.
HIGHS RANGE FROM THE MID 60S NW OF THE IL RIVER TO THE UPPER 70S
AND LOWER 80S ACROSS SE IL. BEST CHANCES OF SHOWERS AND
THUNDERSTORMS OVER THE AREAS WED NIGHT THROUGH THU NIGHT AS STRONG
COLD FRONT MOVES EASTWARD OVER IL THU AFTERNOON/EVENING. SPC HAS
MUCH OF AREA IN A SLIGHT RISK OF SEVERE STORMS DURING THIS TIME
FOR DAMAGING WIND GUSTS WITH A SQUALL LINE AND LARGE HAIL ALSO
A RISK. HEAVIEST RAINS TO OCCUR WED NIGHT THROUGH THU NIGHT WITH
2-4 INCHES POSSIBLE AND HEAVIEST OVER THE IL RIVER VALLEY. HIGHS
THU TRICKING DEPENDING ON HOW FAST COLD FRONT MOVES INTO AREA...
BUT UPPER 70S AND LOWER 80S POSSIBLE OVER EASTERN IL ESPECIALLY
NEAR THE WABASH RIVER WHILE TEMPS EXPECTED TO FALL OVER THE IL
RIVER VALLEY THU AFTERNOON.
COLD FRONT PASSES EAST OF IL FRI BUT STRONG UPPER LEVEL TROF
MOVING INTO AREA TO CONTINUE LOW CLOUDS ALONG WITH A GOOD CHANCE
OF SHOWERS. COULD BE COLD ENOUGH FOR A CHANCE OF LIGHT SNOW
SHOWERS TOO NORTH OF PEORIA FRIDAY MORNING THOUGH BEST CHANCES OF
SNOW SHOWERS IS FURTHER NW OVER NW IL. HIGHS FRI ONLY 45-50 OVER
CENTRAL IL AND LOWER 50S IN SE IL.
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
CANADIAN HIGH PRESSURE TO BUILD INTO IL SAT AND BRING DRY BUT COOL
WEATHER FRIDAY NIGHT THRU SAT NIGHT. LOWS FRIDAY NIGHT IN THE
LOWER 30S CENTRAL IL AND MID 30S SE IL. HIGHS SAT IN THE LOW TO
MID 50S. LOWS SAT NIGHT IN THE MID TO UPPER 30S. CANADIAN HIGH
DRIFTING INTO THE EASTERN GREAT LAKES REGION SUNDAY TO ALLOW TEMPS
TO MODIFY INTO THE UPPER 50S AND LOWER 60S SUNDAY AND INTO THE LOW
TO MID 60S MONDAY. A COLD FRONT APPROACHING THE MS VALLEY MONDAY
TO GIVE CENTRAL AND WESTERN IL CHANCES OF SHOWERS AND ISOLATED
THUNDERSTORMS WHICH CONTINUES ACROSS AREA MONDAY NIGHT/TUE AS COLD
FRONT SWEEPS THROUGH BRINGING COOLER AIR TUE ON BREEZY NW WINDS.
ECMWF AND GFS MODELS FAIRLY SIMILAR WITH THIS WEATHER SYSTEM EARLY
NEXT WEEK.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1034 AM CDT TUE APR 16 2013
.DISCUSSION...
ISSUED 1030 AM CDT TUE APR 16 2013
COLD FRONT HAS PUSHED JUST SOUTH OF OUR CWA...BUT WAS CLOSE ENOUGH
TO LAWRENCEVILLE THAT TEMPERATURES THERE ARE STILL IN THE MID 60S.
MOSTLY SEEING 40S ELSEWHERE WITH SOME LOWER 50S. ELEVATED
CONVECTION NORTH OF THE BOUNDARY HAS BEEN INCREASING OVER CENTRAL
ILLINOIS AS IT MOVES OUT OF MISSOURI...AND COVERED MOST OF THE
CWA AT 1030 AM EXCEPT FOR THE FAR NORTHWEST AND FAR SOUTHEAST.
LATEST RAP MODEL SHOWING THE SCATTERED CONVECTION CONTINUING
ACROSS MUCH OF THE CWA INTO THIS AFTERNOON...WITH LESS COVERAGE
NORTHWEST OF THE ILLINOIS RIVER. HAVE SENT OUT SOME ZONE/GRID
UPDATES TO INCREASE THE RAIN CHANCES TODAY...WITH SOME MINOR
ADJUSTMENTS TO TEMPERATURES REQUIRED AS WELL.
GEELHART
&&
.HYDROLOGY...
ISSUED 1030 AM CDT TUE APR 16 2013
EARLY LOOK AT 12Z MODEL RUNS CONTINUE TO SUPPORT AN INCREASING
POOL OF MOISTURE INTO ILLINOIS ON WEDNESDAY...WITH PRECIPITABLE
WATER VALUES UP TO AROUND 1.5 TO 1.6 INCHES BY LATE WEDNESDAY
AFTERNOON...WHICH IS ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL.
BULK OF THE HEAVIEST RAIN EXPECTED WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. LATEST QPF FORECAST SHOWS OVER 3 INCHES ACROSS A
LARGE PART OF THE FORECAST AREA THROUGH FRIDAY...WITH 2-3 INCHES
ACROSS ABOUT THE SOUTHEAST THIRD. PROBABILITY FORECASTS FROM THE
WEATHER PREDICTION CENTER SHOW A 50-60 PERCENT CHANCE OF RECEIVING
AT LEAST 2.5 INCHES OF RAIN FROM WEDNESDAY EVENING THROUGH
THURSDAY EVENING.
CURRENTLY ONLY THE ILLINOIS RIVER AT HAVANA AND BEARDSTOWN ARE IN
FLOOD...BUT MORE FLOODING IS EXPECTED ACROSS MANY RIVERS. STANDARD
RIVER FORECASTS ONLY ACCOUNT FOR 24-HOUR QPF...BUT RFC CONTINGENCY
FORECASTS BASED ON 72-HOUR QPF SHOW POTENTIAL FOR MODERATE OR
MAJOR FLOODING IN SOME CASES.
HAVE SENT OUT A HYDROLOGIC OUTLOOK TO ADDRESS THE HEAVY RAIN
POTENTIAL...WHILE REMAINING MODEL GUIDANCE IS DIGESTED TO
DETERMINE THE POTENTIAL FOR ANY FLOOD WATCHES WITH THE AFTERNOON
FORECAST PACKAGE.
GEELHART
&&
.AVIATION...
ISSUED 645 AM CDT TUE APR 16 2013
CLOUDS REMAIN OVER THE REGION AND WILL LIKELY STAY THAT WAY
THROUGH THE PERIOD. MAIN QUESTION IS WHAT WILL THE CIG HEIGHTS BE
THROUGH THE PERIOD AND WHEN WILL PCPN RETURN. SPI/PIA/BMI WILL ALL
BE VFR AT START AND THROUGH MOST OF THE PERIOD...UNTIL PCPN MOVES
BACK OVER THE SITES LATE THIS EVENING AND INTO THE OVERNIGHT
HOURS. FOR DEC...BASED ON SATELLITE TRENDS BELIEVE DEC WILL START
AS VFR...BUT LOWER MVFR CIGS MAY LINGER IN THE AREA FOR COUPLE OF
HOURS...SO HAVE 2HR TEMPO GROUP FIRST COUPLE OF HOURS THIS
MORNING. BASED ON SATELLITE TRENDS...CMI SHOULD START WITH MVFR
CIGS...BUT IFR CIGS ARE THERE NOW SO HAVE A ONE HOUR TEMPO GROUP
FOR IFR AND THEN 2HR TEMPO GROUP FOR MVFR CIGS...SINCE VFR CIGS
SHOULD BE AT THE SITE IN NEXT COUPLE OF HOURS. THEN DEC AND CMI
SHOULD BE VFR THROUGH THE DAY...AND LIKE THE OTHER SITES...NOT
BECOME MVFR TIL PCPN MOVES BACK INTO THE AREA. UNSURE HOW LOW CIGS
WILL GET LATER TONIGHT WITH PCPN...BUT WILL START WITH MVFR...BUT
COULD GET LOWER. WINDS WILL BE NORTHERLY TO START TODAY AND THEN
GRADUALLY SHIFT TO NORTHEAST-EAST BY THIS EVENING. WIND SPEEDS
WILL BE AROUND 10KTS OR LESS THROUGH THE PERIOD.
AUTEN
&&
.PREV DISCUSSION...
ISSUED 330 AM CDT TUE APR 16 2013
VERY UNSETTLED WEATHER PATTERN TO OCCUR THROUGH FRIDAY ACROSS
CENTRAL AND SE IL WITH PERIODS OF SHOWERS AND THUNDERSTORM GIVING
2-4 INCHES OF RAIN BY FRIDAY WITH THE HEAVIEST AMOUNTS FROM I-55 NW.
SPC ALSO CONTINUES SLIGHT RISK OF SEVERE STORMS ACROSS AREAS WEST OF
I-57 WED NIGHT AND ACROSS MUCH OF REGION THU/THU EVENING. LIKE
YESTERDAYS MODEL RUNS...THE 00Z MODEL SUITE TODAY CONTINUES SLOWER
TREND WITH POTENT COLD FRONT MOVING EASTWARD ACROSS IL THU
AFTERNOON/EVENING.
SHORT TERM...TODAY THROUGH FRIDAY
MCS FROM CENTRAL MO NE ACROSS CENTRAL IL INTO NW INDIANA HAS
GRADUALLY BEEN WEAKENING THE PAST HOUR OR SO. A BROKEN LINE OF
THUNDERSTORMS WITH HEAVY RAINS WAS ALONG SE EDGE OF THIS MCS FROM
TAYLORVILLE AND SHELBYVILLE TO TUSCOLA AND CHRISMAN. HAD A FEW
REPORTS OF HAIL BETWEEN MIDNIGHT AND 1 AM OVER PARTS OF SANGAMON AND
LOGAN COUNTIES. COLD FRONT HAD SAGGED SLOWLY INTO SE IL...SE OF
I-70 EARLY THIS MORNING BEING PULLED SE BY MCS AND 1012 MB LOW
PRESSURE NEAR INDY. COLD FRONT EXTENDED SW TO A 1000 MB LOW
PRESSURE OVER EASTERN NM. BROAD SW UPPER LEVEL FLOW OVER THE
COUNTRY HAS BEEN SLOWLY DOWN THE SE PROGRESSION OF THIS COLD FRONT.
RADAR ESTIMATED 1.5-2.5 INCHES OF RAIN ALONG AND JUST SE OF A
RUSHVILLE TO BLOOMINGTON LINE.
CONVECTION TO CONTINUE TO WEAKEN DURING THE MORNING WITH AS LOW
LEVEL JET THAT PEAKED AROUND 40 KTS WEAKENS. BEST CHANCES OF
SHOWERS AND THUNDERSTORMS TODAY SHIFTS INTO SE IL CLOSER TO
FRONTAL BOUNDARY WHICH CONTINUES TO SLOWLY SAG SOUTHWARD TODAY...
WHILE DRIER AND COOLER TO THE NORTH. SCATTERED SHOWERS AND
THUNDERSTORMS POSSIBLE THIS AFTERNOON ESPECIALLY FROM I-72 SOUTH.
HIGHS TODAY RANGE FROM THE MID 50S OVER THE IL RIVER VALLEY FROM
I-55 NW TO THE UPPER 60S TO NEAR 70F IN FAR SE IL ALONG HIGHWAY
50.
INCREASING LOW LEVEL JET TO INCREASE CHANCES OF SHOWERS AND
THUNDERSTORMS TONIGHT ESPECIALLY OVERNIGHT WHEN SPC HAS SLIGHT
CHANCE OF SEVERE OVER SE IL AND SW OF SPRINGFIELD. MAINLY A HAIL
THREAT SW OF SPRINGFIELD WHILE HAIL AND WIND IN FAR SE IL NEAR
HIGHWAY 50.
FRONTAL BOUNDARY TO BEGIN TO LIFT BACK NORTHWARD OVER CENTRAL IL
WED WITH SHOWERS AND THUNDERSTORMS LIKELY ESPECIALLY NW AREAS.
HIGHS RANGE FROM THE MID 60S NW OF THE IL RIVER TO THE UPPER 70S
AND LOWER 80S ACROSS SE IL. BEST CHANCES OF SHOWERS AND
THUNDERSTORMS OVER THE AREAS WED NIGHT THROUGH THU NIGHT AS STRONG
COLD FRONT MOVES EASTWARD OVER IL THU AFTERNOON/EVENING. SPC HAS
MUCH OF AREA IN A SLIGHT RISK OF SEVERE STORMS DURING THIS TIME
FOR DAMAGING WIND GUSTS WITH A SQUALL LINE AND LARGE HAIL ALSO
A RISK. HEAVIEST RAINS TO OCCUR WED NIGHT THROUGH THU NIGHT WITH
2-4 INCHES POSSIBLE AND HEAVIEST OVER THE IL RIVER VALLEY. HIGHS
THU TRICKING DEPENDING ON HOW FAST COLD FRONT MOVES INTO AREA...
BUT UPPER 70S AND LOWER 80S POSSIBLE OVER EASTERN IL ESPECIALLY
NEAR THE WABASH RIVER WHILE TEMPS EXPECTED TO FALL OVER THE IL
RIVER VALLEY THU AFTERNOON.
COLD FRONT PASSES EAST OF IL FRI BUT STRONG UPPER LEVEL TROF
MOVING INTO AREA TO CONTINUE LOW CLOUDS ALONG WITH A GOOD CHANCE
OF SHOWERS. COULD BE COLD ENOUGH FOR A CHANCE OF LIGHT SNOW
SHOWERS TOO NORTH OF PEORIA FRIDAY MORNING THOUGH BEST CHANCES OF
SNOW SHOWERS IS FURTHER NW OVER NW IL. HIGHS FRI ONLY 45-50 OVER
CENTRAL IL AND LOWER 50S IN SE IL.
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
CANADIAN HIGH PRESSURE TO BUILD INTO IL SAT AND BRING DRY BUT COOL
WEATHER FRIDAY NIGHT THRU SAT NIGHT. LOWS FRIDAY NIGHT IN THE
LOWER 30S CENTRAL IL AND MID 30S SE IL. HIGHS SAT IN THE LOW TO
MID 50S. LOWS SAT NIGHT IN THE MID TO UPPER 30S. CANADIAN HIGH
DRIFTING INTO THE EASTERN GREAT LAKES REGION SUNDAY TO ALLOW TEMPS
TO MODIFY INTO THE UPPER 50S AND LOWER 60S SUNDAY AND INTO THE LOW
TO MID 60S MONDAY. A COLD FRONT APPROACHING THE MS VALLEY MONDAY
TO GIVE CENTRAL AND WESTERN IL CHANCES OF SHOWERS AND ISOLATED
THUNDERSTORMS WHICH CONTINUES ACROSS AREA MONDAY NIGHT/TUE AS COLD
FRONT SWEEPS THROUGH BRINGING COOLER AIR TUE ON BREEZY NW WINDS.
ECMWF AND GFS MODELS FAIRLY SIMILAR WITH THIS WEATHER SYSTEM EARLY
NEXT WEEK.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
712 PM CDT WED APR 17 2013
.UPDATE...
ISSUED AT 711 PM CDT WED APR 17 2013
THUNDERSTORMS HAVE YET TO FORM ALONG THE SURFACE FRONT OVER
SOUTHEAST KS. INSPECTION OF MODIFIED RUC SOUNDINGS INDICATE POOR
LAPSE RATES/RELATIVELY WARM TEMPERATURES THROUGH
700-600MB. SO DESPITE GOOD CONVERGENCE ALONG THE SURFACE
FRONT...NEAR-SURFACE COLD AIR IS LIKELY TOO SHALLOW TO BREAK
THROUGH THE WARMER MID-LEVEL TEMPERATURES...WITH ONLY WEAK
BUOYANCY FROM THE SURFACE-700/600MB. CONSEQUENTLY...FEEL THE HIGH-
END SEVERE WEATHER THREAT INCLUDING TORNADOES...DAMAGING WINDS AND
VERY LARGE HAIL IS WANING...ALTHOUGH STILL CANNOT RULE OUT SEVERE
ACTIVITY EITHER DEVELOPMENT OVER MOVING NORTHEAST OUT OF OK INTO
SE KS.
WONDERING IF THE HIGHER CONFIDENCE SCENARIO (SUPPORTED BY THE
RUC)...IS SHOWERS/THUNDERSTORMS RAMPING UP IN COVERAGE/INTENSITY
LATER THIS EVENING OVER SOUTH-CENTRAL/CENTRAL KS IN RESPONSE TO
INCREASING ISENTROPIC ASCENT AND MOISTURE TRANSPORT AHEAD OF
APPROACHING DEEP MID/UPPER TROUGH...WITH A BROAD SHIELD OF
MODERATE TO HEAVY SHOWERS/THUNDERSTORMS PUSHING EAST ACROSS
EASTERN HALF OF KS OVERNIGHT ALONG THE ADVANCING 850-700MB FRONT.
GIVEN THE PRESENCE OF AMPLE ELEVATED INSTABILITY AND EFFECTIVE
DEEP LAYER SHEAR...LARGE HAIL IS POSSIBLE. POCKETS OF HEAVY RAIN
AND MINOR FLOODING ARE POSSIBLE...ALONG WITH MODEST RISES IN AREA
RIVERS...SO WILL KEEP THE FLOOD WATCH GOING OVER SOUTHEAST KS.
ADDITIONALLY...ENOUGH LOW-LEVEL COLD AIR MAY FILTER SOUTHEAST TO
RESULT IN A WINTRY MIX OVER CENTRAL KS AFTER MIDNIGHT...SO WILL
KEEP A WINTER WX ADVISORY GOING THERE.
ADK
&&
UPDATE ISSUED AT 652 PM CDT WED APR 17 2013
UPDATED AVIATION SECTION BELOW.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 237 PM CDT WED APR 17 2013
CONVECTION
PRE AND POST FRONTAL STRONG TO SEVERE CONVECTION WITH HEAVY
RAINFALL EXPECTED THRU THIS EVENING ACROSS PORTIONS OF CENTRAL
AND SOUTHEAST KANSAS. THE HIGHER IMPACT SEVERE IS STILL EXPECTED
ALONG THE SURFACE FRONT ACROSS SOUTHEAST KANSAS WITH DAMAGING
WINDS...LARGE HAIL AND A TORNADO POSSIBLE DURING THE EARLY
EVENING. HOWEVER ELEVATED INSTABILITY OVER THE COLD AIR WILL
STILL SUPPORT SOME HAILERS FURTHER WEST ACROSS PORTIONS OF
CENTRAL KANSAS. CONVECTION WILL TEND TO REDEVELOP AND
REPEAT/TRAIN OVER SOME AREAS WHICH PORTENDS TO HEAVY RAINFALL
AND FLOOD POTENTIAL. THE LONGER DURATION APPEARS TO BE OVER
SOUTHEAST KANSAS INTO THE OVERNIGHT HOURS...SO WILL ISSUE A
FLOOD WATCH FOR THESE AREAS.
WINTRY PRECIP
NEXT CHALLENGE IS WITH THE SURGE OF COLD AIR AND POST FRONTAL
PRECIPITATION LATER TONIGHT INTO THURSDAY MORNING. WHILE NOT
QUITE AS IMPRESSIVE AS LAST WEEK...IT DOES LOOK LIKE WE WILL GET
A TRANSIENT AREA OF A LIGHT WINTRY MIX ACROSS CENTRAL KANSAS WITH
THE NAM PREFERRED IN THIS REGARD. DEPENDING ON CHANGEOVER AND
MOISTURE DEPTH/LIFT...THIS COULD BE SOME LIGHT FREEZING RAIN
AND/OR SNOW OR FREEZING DRIZZLE...THOUGH FOR NOW ANY ACCUMS ARE
STILL EXPECTED TO BE LIGHT. THAT SAID...THIS IN COMBO WITH STRONG
NORTH WINDS NEAR ADVISORY CRITERIA INTO EARLY THURSDAY
MORNING...PLAN TO ISSUE A WINTER WEATHER ADVISORY FOR A PORTION
OF CENTRAL KANSAS. SOME LIGHT MIXED PRECIP COULD BE OBSERVED AS
FAR EAST AS THE FLINT HILLS INTO LATER THURSDAY MORNING...HOWEVER
TEMPERATURES SHOULD RECOVER TO A BIT ABOVE FREEZING BY THEN SO OF
LITTLE CONSEQUENCE EXPECTED.
FREEZE/RECORD COLD THURSDAY NIGHT
THE THIRD CONCERN IS WITH RECORD COLD AND WIDESPREAD FREEZE
EXPECTED. THIS LOOKS TO BE A PURE COLD ADVECTION TYPE WITH
MINS INTO THE MID TO UPPER 20S IN MOST LOCALES DESPITE A BIT
OF NOCTURNAL/EARLY MORNING WIND. CONSIDERED A HEADLINE/WATCH
FOR THIS...HOWEVER WITH THE OTHER MORE IMMINENT IMPACTS IN
THE SHORTER TERM HAVE DECIDED TO HOLD OFF AND MAINTAIN MENTION
IN THE HAZARDOUS WEATHER OUTLOOK. HOWEVER IF CONFIDENCE
REMAINS HIGH...A FREEZE WARNING WILL LIKELY BE FORTHCOMING IN
THE NEXT FORECAST CYCLE OR TWO.
SOME MODERATION AND RETURN TO DRY WEATHER IS EXPECTED FOR
FRIDAY AND SATURDAY AND MADE ONLY A SLIGHT UPTWEAK TO THE
TEMPERATURES CLOSER TO SEASONAL CLIMO BY SATURDAY.
DARMOFAL
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 237 PM CDT WED APR 17 2013
SINCE MAIN FOCUS HAS BEEN ON SHORT TERM DO NOT PLAN ON ANY
SIGNIFICANT CHANGES TO THE OUTER PERIODS WITH THIS FORECAST.
MEDIUM RANGE STILL SUPPORTS ANOTHER COOL DOWN EARLY NEXT
WEEK WITH SOME PRECIP CHANCES AHEAD OF AND JUST BEHIND THE
FRONTAL PASSAGE FROM SUNDAY INTO TUESDAY.
DARMOFAL
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 652 PM CDT WED APR 17 2013
A SHARP FRONTAL ZONE WILL BE THE FOCUS FOR NUMEROUS/WIDESPREAD
SHOWERS AND THUNDERSTORMS ACROSS THE EASTERN 1/2 TO 2/3 OF KS
TONIGHT. A RELATIVE LULL IN ACTIVITY IS ANTICIPATED THIS
EVENING...WITH SHORT-RANGE GUIDANCE SUGGESTING WIDESPREAD
SHOWERS/THUNDERSTORMS RAMPING UP BETWEEN 03-05Z. HEAVY
RAINFALL...STRONG ERRATIC WINDS AND HAIL WILL BE POSSIBLE WITH
STRONGEST ACTIVITY OVERNIGHT. AS COLDER AIR CONTINUES FILTERING
SOUTHEAST...KRSL COULD POTENTIALLY SEE A MIX OF RAIN...FREEZING
RAIN...SLEET AND SNOW AFTER 05Z. OTHERWISE...LIFR/IFR CIGS WILL
GRADUALLY IMPROVE FROM THE NORTHWEST TONIGHT AND TOMORROW...AS
COLDER AND DRIER AIR MOVES IN.
ADK
&&
.FIRE WEATHER...
ISSUED AT 237 PM CDT WED APR 17 2013
GRASSLAND FIRE DANGER WILL REMAIN LOW DUE TO WIDESPREAD
PRECIPITATION TONIGHT INTO EARLY THURSDAY. A DRYING PROCESS
WILL BEGIN INTO THE START OF THE WEEKEND BEFORE ANOTHER CHANCE
FOR RAIN SUNDAY INTO EARLY NEXT WEEK.
KED
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 34 43 28 56 / 90 30 0 0
HUTCHINSON 32 41 27 56 / 90 30 0 0
NEWTON 33 41 27 54 / 90 40 0 0
ELDORADO 34 43 28 55 / 90 40 0 0
WINFIELD-KWLD 36 45 29 59 / 90 40 0 0
RUSSELL 29 40 24 56 / 90 50 0 0
GREAT BEND 29 40 25 56 / 90 30 0 0
SALINA 32 41 26 55 / 90 50 0 0
MCPHERSON 32 40 26 56 / 90 40 0 0
COFFEYVILLE 45 49 31 58 / 100 60 10 0
CHANUTE 44 46 30 57 / 100 60 10 0
IOLA 43 45 30 56 / 100 60 10 0
PARSONS-KPPF 45 48 30 56 / 100 60 10 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 1 AM TO 7 AM CDT THURSDAY FOR
KSZ032-033-047-048-050-067-082.
FLOOD WATCH THROUGH THURSDAY MORNING FOR KSZ070>072-094>096-
098>100.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
703 PM CDT WED APR 17 2013
...UPDATED AVIATION SECTION FOR 00Z TAFS...
.SYNOPSIS...
ISSUED AT 343 PM CDT WED APR 17 2013
THE 12Z UPPER AIR ANALYSIS SHOWED A DEEP TROUGH EXTENDING FROM THE
NORTHERN ROCKIES INTO THE GREAT BASIN. A 150+ KNOT UPPER LEVEL JET
WAS IN THE BASE OF THE TROUGH OVER SOUTHERN ARIZONA AND NEW MEXICO.
AT THE 850 MB LEVEL...LOW PRESSURE WAS CENTERED OVER NORTHERN NEW
MEXICO. EAST OF THE LOW...A NEARLY STATIONARY FRONTAL BOUNDARY
EXTENDED EAST ACROSS THE NORTHERN TEXAS PANHANDLE INTO SOUTH CENTRAL
AND EASTERN KANSAS. AT THE SURFACE...THE FRONTAL BOUNDARY EXTENDED
FROM EASTERN NEW MEXICO ACROSS WEST TEXAS AND THEN NORTHEAST ACROSS
CENTRAL OKLAHOMA. WARM AND MOIST AIR WAS STREAMING NORTH ACROSS
TEXAS INTO THE CENTRAL PLAINS AND WAS CONTRIBUTING TO A VERY
UNSTABLE AIRMASS ACROSS OKLAHOMA INTO SOUTH CENTRAL AND SOUTHEAST
KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 343 PM CDT WED APR 17 2013
THERE WILL BE A CONTINUED THREAT FOR SEVERE WEATHER OVER SOUTH
CENTRAL KANSAS THIS EVENING. THE NAM IS INDICATING THAT THE 850 MB
FRONTAL BOUNDARY WILL BE IN THE AREA FROM COLDWATER AND MEDICINE
LODGE TO ST JOHN THIS EVENING BEFORE SHIFTING SOUTH OF THE AREA BY
MIDNIGHT. RAP MODEL SOUNDINGS SHOW AROUND 1500 J/KG OF ELEVATED CAPE
IN THAT AREA. AS THE SOUTHWESTERN U.S. UPPER JET PROPAGATES EASTWARD
INTO THE SOUTHERN PLAINS THIS EVENING...INCREASING UPWARD VERTICAL
MOTION COULD AID IN THE DEVELOPMENT OF ADDITIONAL THUNDERSTORMS.
THERE WILL BE A THREAT FOR HAIL UP TO QUARTER SIZE IN THAT AREA.
THE UPPER TROUGH MOVES EAST OUT OVER THE HIGH PLAINS TONIGHT. MODEL
SOUNDINGS ARE INDICATING SATURATED CONDITIONS GENERALLY BELOW 700 MB
THROUGH THE NIGHT WITH THE LEVELS ABOVE 700 MB SATURATING FOR A 3-6
HOUR TIME FRAME DURING THE NIGHT. LOCATIONS FARTHER WEST ACROSS
WESTERN KANSAS WILL SEE AREAS OF DRIZZLE CONTINUING ALONG WITH A
CHANCE FOR RAIN SHOWERS. THERE WILL BE A TRANSITION FROM RAIN TO
SNOW WITH A PERIOD OF SLEET/FREEZING RAIN POSSIBLE IN BETWEEN. THE
ATMOSPHERE SHOULD COOL OFF ENOUGH FOR SNOW TO DEVELOP OVER WEST
CENTRAL KANSAS DURING THE EVENING HOURS WITH THIS SPREADING INTO
CENTRAL KANSAS AFTER MIDNIGHT. GIVEN THE SHORT WINDOW OF OPPORTUNITY
FOR THE SEEDER/FEEDER MECHANISM TO OCCUR...DO NOT EXPECT SNOW
AMOUNTS TO BE SIGNIFICANT WITH ONLY SOME LIGHT ACCUMULATIONS
POSSIBLE ON GRASSY AREAS. AM NOT ANTICIPATING ANY SIGNIFICANT ICE
ACCUMULATIONS TO OCCUR ALTHOUGH SOME ELEVATED SURFACES COULD GET
SOME LIGHT COATINGS.
AS COLD AIR ADVECTION INCREASES...STRONG NORTHERLY WINDS DEVELOP
OVER THE WESTERN HIGH PLAINS AND SPREAD EASTWARD TONIGHT. LOW LEVEL
WINDS THROUGH THE 850 MB LEVEL INCREASE TO 40-50 KNOTS OVERNIGHT
WHICH SHOULD SUPPORT WIND ADVISORY CRITERIA WINDS LATER TONIGHT INTO
THURSDAY MORNING. HAVE ISSUED A WIND ADVISORY FOR MIDNIGHT TONIGHT
UNTIL NOON THURSDAY FOR ALL OF SOUTHWEST AND CENTRAL KANSAS.
PRECIPITATION SHOULD BE WINDING DOWN FAIRLY QUICKLY LATE TONIGHT AND
THURSDAY MORNING AS THE UPPER SYSTEM MOVES EAST OF THE REGION.
CLOUDS SHOULD BE BREAKING UP FROM WEST TO EAST DURING THE DAY. WITH
SOME SUN...AFTERNOON HIGH TEMPERATURES MAY BE ABLE TO CLIMB INTO THE
LOWER 40S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 338 PM CDT WED APR 17 2013
FRIDAY:
UPPER LEVEL WNW FLOW WILL CONTINUE ON FRIDAY. AT THE SURFACE, HIGH
PRESSURE WILL RIDGE ACROSS THE PLAINS. NORTHWESTERLY WINDS WILL
EVENTUALLY BECOME SOUTHERLY AFTER SUNSET. HIGHS WILL BE IN THE 50S
AND LOWS WILL BE IN THE 20S. NO PRECIPITATION IS EXPECTED AS DRY
FLOW ALOFT AND LACK OF BL MOISTURE CONTINUES.
WEEKEND:
AN UPPER LEVEL TROUGH WILL DIG ACROSS THE CENTRAL AND SOUTHERN
ROCKIES THROUGH THE WEEKEND. THIS WILL PROMOTE A WARM AIR ADVECTION
PATTERN DOWNSTREAM ACROSS OUR REGION. A WARM 850 HPA PLUME WILL
ADVECT OFF THE ROCKIES AND OUT ACROSS SOUTHWEST KANSAS SATURDAY.
THIS WILL FAVOR DEEP MIXING AND HIGHS IN THE UPPER 60S TO LOWER 70S.
OVERNIGHT LOWS WILL MODERATE AS WELL WITH 30S ON SATURDAY AND 40S ON
SUNDAY. TEMPERATURES AROUND 70 DEG F CAN BE EXPECTED SUNDAY AS THE
AFOREMENTIONED WARM PLUME CONTINUES ACROSS THE REGION. THERE COULD BE
A FEW SHOWERS ACROSS SC/S KANSAS IN ASSOCIATION WITH WARM ADVECTION
BUT CONFIDENCE IS LOW AND MODELS ARE FAIRLY LIGHT ON QPF.
NEXT WEEK AND BEYOND:
A MAJOR CHANGE IN WEATHER IS POSSIBLE MONDAY OR TUESDAY. ANOTHER TROF
DIGGING OUT OF THE NORTHERN ROCKIES WILL USHER IN THE PASSAGE OF A
SIGNIFICANT COLD FRONT. THE ECMWF IS FAIRLY COLD WITH 850 HPA
TEMPERATURES DECREASING DOWN TO -6 DEG C. BOTH THE GFS AND ECMWF
INDICATE SOME LIGHT SNOWFALL ACROSS THE REGION ASSOCIATED WITH THIS
FRONT. CONFIDENCE IS LOW FOR PRECIPITATION TYPE BUT THERE IS HIGHER
CONFIDENCE IN LOWER TEMPERATURES WITH 40S AND 50S FOR HIGHS BY
TUESDAY/WEDNESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 659 PM CDT WED APR 17 2013
POOR AVIATION CONDITIONS WILL CONTINUE THROUGH THE NIGHT AS A
ROUND OF PRECIPITATION DEVELOPS THIS EVENING AND LINGERS THROUGH
THE OVERNIGHT HOURS. THE PRECIPITATION TYPE WILL BE RAIN AT GCK,
DDC, AND HYS THROUGH THE LATE EVENING...BUT A TRANSITION TO SLEET
AND/OR SNOW IS EXPECTED LATE THIS EVENING AND ESPECIALLY AFTER
MIDNIGHT. ONLY LIGHT PRECIPITATION IS EXPECTED, HOWEVER, AFTER
MIDNIGHT SO NO ACCUMULATION OF SIGNIFICANCE IS EXPECTED. STRONG
NORTH WINDS OF 25 OR MORE KNOTS WILL DEVELOP LATE AS THE MAIN
UPPER LEVEL STORM SYSTEM APPROACHES. IFR CEILINGS WILL PREVAIL AT
LEAST THROUGH THE MID MORNING HOURS THURSDAY...BUT GRADUALLY
SCATTERING OUT TO VFR CONDITIONS THEREAFTER AS THE STORM EXITS THE
WESTERN PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 27 38 24 59 / 70 10 0 0
GCK 27 37 22 60 / 60 10 0 0
EHA 26 39 23 60 / 40 10 0 0
LBL 28 41 23 60 / 50 10 0 0
HYS 28 36 23 58 / 80 30 0 0
P28 31 44 28 60 / 70 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM MIDNIGHT CDT /11 PM MDT/ TONIGHT TO NOON CDT
/11 AM MDT/ THURSDAY FOR KSZ030-031-043>046-061>066-074>081-
084>090.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...GERARD
LONG TERM...SUGDEN
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS GOODLAND KS
512 PM MDT WED APR 17 2013
.SHORT TERM...(THIS AFTERNOON THROUGH THURSDAY)
ISSUED AT 132 PM MDT WED APR 17 2013
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS POSITIVELY
TITLED LONGWAVE TROUGH EXTENDING SOUTH ALONG CENTRAL ROCKIES WITH
DRY SLOT/AREA OF SUBSIDENCE IN PLACE AHEAD OF THIS OVER WESTERN
KANSAS AND CENTRAL NEBRASKA. LOW AT THE SURFACE A STALLED FRONT
EXTENDS FROM THE TEXAS PANHANDLE ACROSS CENTRAL OKLAHOMA TO
SOUTHEAST KANSAS. NORTHWEST FLOW IS IN PLACE ACROSS OUR CWA WITH
VERY MOIST BL CONDITIONS PERSISTING...WHICH HAS RESULTED IN AREAS
OF FOG AND DRIZZLE PERSISTING THROUGH THE AFTERNOON HOURS. WITH
TEMPERATURES NEAR OR BELOW FREEZING...WE COULD CONTINUE TO SEE
LIGHT ICE ACCUMULATIONS ON ELEVATED SURFACES BEFORE SNOW DEVELOPS
LATER.
THE PRIMARY FORECAST FOCUS IS ON DEVELOPING WINTER STORM FOR
LATE THIS AFTERNOON THROUGH EARLY THURSDAY MORNING.
UPPER LEVEL TROUGH IS PROGGED TO SHIFT EAST THIS EVENING...WITH
LARGE SCALE ASCENT AND MID LEVEL MOISTURE OVERSPREADING THE CWA.
BROAD AXIS OF MID LEVEL FRONTOGENESIS IS EXPECTED TO SET UP ACROSS
THE NORTHWEST HALF OF OUR CWA THIS EVENING. LIGHT SNOW AND
BANDS OF MODERATE SNOW TRAINING FROM THE SOUTH TO THE NORTH. WITH
SURFACE TEMPS ALREADY BELOW FREEZING THIS AFTERNOON IN THE
NORTHWEST AND A SECOND COLD SURGE EXPECTED LATE THIS
AFTERNOON/EARLY THIS EVENING...I THINK WE SHOULD SEE A FAST
RAIN/SNOW CHANGEOVER WITH ALL SNOW IN OUR CWA THIS EVENING AND
TONIGHT. THERE IS QUITE A BIT OF SPREAD REGARDING QPF
VALUES...WITH GFS THE HIGH OUTLIER. WITH SREF (TRADITIONALLY HIGH)
AND OTHER GUIDANCE MORE IN LINE WITH PREVIOUS FORECAST QPF/SNOW
TOTALS I DISCOUNTED THE GFS SOLUTION AND ONLY MADE MINOR CHANGES
TO AMOUNTS. WE ARE CURRENTLY FORECAST 3-5 INCHES FOR MOST OF THE
AREA...WITH HIGHS AMOUNTS MORE LIKELY NORTH OF INTERSTATE 70.
OTHER CONCERN (AND POSSIBLY THE HIGHER IMPACT) IS STRONG WINDS
PROGGED TO DEVELOP THIS EVENING. ALL GUIDANCE IS SUPPORTIVE OF
GUSTY WINDS...HOWEVER GFS/MAV CONTINUES TO BE THE HIGH OUTLIER
WITH GUSTS IN EXCESS OF 60 MPH. NAM/SREF/ECMWF ALL ARE LOWER...AND
WITH BEST PRESSURE RISES ADVERTISED TO BE FURTHER SOUTH...THESE
SOLUTIONS MAY BE MORE REASONABLE. I USED A BLEND THAT FAVORED THE
NAM MIXED LAYER WINDS AND NUDGED A LITTLE TOWARDS GFS/MAV WHICH
RESULTS IN GUSTS THIS EVENING TO 50 MPH. EVEN WITH THE LOWER END
OF GUIDANCE WE SHOULD SEE BLOWING SNOW WITH REDUCED VISIBILITIES. THE
SPREAD IN GUIDANCE AND POSSIBLE LIMITED DURATION OF THE STRONGEST
WINDS IN OUR AREA RAISES QUESTIONS TO HOW LOW THESE VISIBILITIES WILL
BE AND HOW LONG. I FELT THE WINTER WEATHER ADVISORY WAS APPROPRIATE
WITH BRIEF BLIZZARD CONDITIONS POSSIBLE. IF WINDS END UP BEING MORE
IN LINE WITH GFS SOLUTION WE MAY NEED TO CONVERT WESTERN LOCATIONS TO
A BLIZZARD WARNING...CONFIDENCE JUST ISNT THERE RIGHT NOW.
THE WORST CONDITIONS SHOULD BE 03Z THROUGH ABOUT 09Z TONIGHT...WITH
SNOW ENDING QUICKLY FROM THE WEST TO THE EAST EARLY THU MORNING.
WE COULD SEE LINGERING SNOW INTO THU IN OUR NORTHEAST...HOWEVER
WITH BEST FORCING/MOISTURE OUTSIDE OUR AREA I AM NOT ANTICIPATING
VERY MUCH ADDITIONAL ACCUMULATION. WE SHOULD SEE ANOTHER BLUSTERY
DAY THURSDAY WITH HIGHS IN THE 30S AND GUSTY WINDS THROUGH THE
DAY. GFS/MAV IS AGAIN MUCH HIGHER ON WINDS THU AND MIGHT SUPPORT
ADVISORY CRITERIA. I WILL HAVE TO SEE WHAT KIND OF BIAS THE GFS
HAD TONIGHT TO HAVE ANY ANY CONFIDENCE IN THE HIGHER WINDS THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 316 PM MDT WED APR 17 2013
FORECAST PROBLEMS WILL BE HOW MUCH IT WARMS UP THROUGH THE WEEKEND
BEFORE THE NEXT COLD FRONT MOVES THROUGH AND THE PRECIPITATION
CHANCES THIS WEEKEND AND CONTINUING INTO THE BEGINNING OF NEXT WEEK.
SATELLITE SHOWING THE LARGE SCALE FLOW PATTERN BEING AMPLIFIED AND
BLOCKY FROM THE PACIFIC INTO THE EASTERN NORTH AMERICA.
THURSDAY NIGHT...SYSTEM THAT WILL HAVE BROUGHT THE AREA SNOW AND
WIND WILL CONTINUE TO MOVE AWAY. MODERATE GRADIENT CONTINUES THROUGH
THE NIGHT AND LOOKS LIKE THE WINDS WILL STAY UP ENOUGH TO KEEP THE
TEMPERATURES FROM BOTTOMING OUT.
FRIDAY/FRIDAY NIGHT...RIGHT REAR QUADRANT OF UPPER JET GOES ACROSS
THE NORTHERN PORTION OF THE AREA DURING THE DAY. AT THIS TIME WITH
A LARGE DRY LAYER IN THE LOW AND MID LEVELS...THIS ONLY LOOKS LIKE
IT WILL SPREAD CLOUDS ACROSS THE AREA. DURING THE NIGHT...THE LEFT
FRONT QUADRANT IS NEAR OR JUST SOUTHWEST OF THE SOUTHWEST PORTION OF
OUR AREA. AS IT LOOKS THE MAIN MID LEVEL LIFT LOOKS TO STAY TO NORTH
AND SOUTH OF THE AREA. ALSO PROBLEM AGAIN LOOKS TO BE A LACK OF
MOISTURE IN THE LOW LEVELS. SO WILL KEEP THIS PERIOD DRY AS WELL.
CLOUDS WILL DECREASE THROUGH THE NIGHT WITH THE MODELS SHOWING A
HIGHLY VARIABLE WIND FIELD AND DISAGREE WITH EACH OTHER. WILL TEND
TOWARD THE COOLER SIDE.
SATURDAY...MAIN JET REMAINS SOUTH AND WEST OF THE AREA. HIGHER LEVEL
CLOUD COVER INCREASES THROUGH THE DAY AS A COUPLE DIFFERENT SHORTWAVE
TROUGHS MOVE THROUGH. THIS MAY HINDER THE TEMPERATURES. HOWEVER...
MODELS HAVE BEEN MISSING THE BOAT ON TEMPERATURES HERE RECENTLY. HAVE
A LIGHT AND VARIABLE WIND FIELD WHICH ALSO DOES NOT BODE WELL FOR
GOING TOO WARM. MODELS HANDLE THIS DIFFERENTLY DUE TO THE DIFFERENT
HANDLING OF THE INCOMING SYSTEM. 700 TO 500 MB PATTERN WOULD
DEFINITELY SUPPORT AN EARLIER SURFACE TROUGH/FRONTAL PASSAGE. MORE
SUPPORT FOR GOING WARMER SO DID NUDGE UP TEMPERATURES A LITTLE BUT
NOT A LOT OF CONFIDENCE IN THIS DUE TO RECENT TEMPERATURE
PERFORMANCE.
NOT A LOT OF SURFACE CONVERGENCE WITH THIS WIND FIELD. PLUS ALL THE
MOISTURE LOOKS TO BE ABOVE 700 MB. SO WILL KEEP THIS PERIOD DRY.
SATURDAY NIGHT THROUGH WEDNESDAY...IN GENERAL THE MODELS ARE
CAPTURING THE OVERALL PATTERN. THE MODELS DROP A SYSTEM INTO THE
NORTH CENTRAL PORTION OF THE COUNTRY SUNDAY INTO MONDAY AND THEN
BRING THE UPPER TROUGH THROUGH AROUND TUESDAY AND THEN EAST OF THE
AREA. HOWEVER...THEY ARE DIFFERING ON THE TIMING OF THE NUMEROUS
SHORTWAVE TROUGHS THAT MOVE THROUGH IN THE WESTERLY FLOW ALOFT PRIOR
TO THE UPPER TROUGH MOVING THROUGH. THEY ALSO DIFFER IN HOW FAR SOUTH
AND HOW FAST THEY TAKE THE UPPER TROUGH THROUGH.
SO IN GENERAL THEY AGREE ON MAKING IT WET BUT NOT THE TIMING. THE
BIGGEST PROBLEM ON TIMING CENTERS AROUND TUESDAY. THE ECMWF TAKES
THE UPPER TROUGH THROUGH SOONER THAN THE GFS AND CANADIAN. SO DID
NOT HAVE ANY PROBLEM WITH WHAT THE CRH INIT GAVE ME WHICH IS
RAMPING UP POPS SUNDAY NIGHT WITH THE HIGHEST POPS MONDAY INTO
MONDAY NIGHT. FOR TUESDAY THE INIT GAVE ME POPS IN THE MIDDLE OF
THE TWO CAMPS AND COULD LIVE WITH THAT. AFTER TUESDAY IT LOOKS DRY.
STRONG COLD FRONT COMES THROUGH LATE SUNDAY NIGHT INTO EARLY MONDAY
MORNING. PER THIS RATHER FAST FRONTAL PASSAGE AND COLLABORATION
CHOSE TO LOWER MONDAY AND TUESDAY MAXES FROM WHAT THE CRH INIT GAVE
ME. OTHERWISE MADE NO OTHER CHANGES
THANKS TO ALL FOR THE COLLABORATION
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 511 PM MDT WED APR 17 2013
DYNAMICS FROM THE UPPER TROUGH WILL MOVE ACROSS THE TERMINALS
TONIGHT BRINGING LIGHT SNOW FOR SEVERAL HOURS UNTIL AROUND 14Z
THURSDAY. STRONG NORTH WIND WILL CAUSE SOME BLOWING SNOW AND REDUCED
VISIBILITIES WITH CONDITIONS DROPPING TO LIFR. CONDITIONS SHOULD
IMPROVE TO MVFR BY AFTERNOON AS THE SYSTEM MOVES AWAY.
&&
.CLIMATE...
ISSUED AT 330 AM MDT WED APR 17 2013
RECORD LOW HIGH TEMPERATURES IN JEOPARDY THURSDAY:
GOODLAND.....38 DEGREES
HILL CITY....47 DEGREES
MCCOOK.......35 DEGREES
BURLINGTON...35 DEGREES
YUMA.........36 DEGREES
COLBY........39 DEGREES
TRIBUNE......40 DEGREES
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY UNTIL 6 AM MDT /7 AM CDT/ THURSDAY FOR
KSZ001>004-013>016-027>029-041-042.
CO...WINTER WEATHER ADVISORY UNTIL 6 AM MDT THURSDAY FOR COZ090>092.
NE...WINTER WEATHER ADVISORY UNTIL 6 AM MDT /7 AM CDT/ THURSDAY FOR
NEZ079>081.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...FS
CLIMATE...JTL
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1206 AM CDT TUE APR 16 2013
.UPDATE...
ISSUED AT 1059 PM CDT MON APR 15 2013
LATEST MODEL GUIDANCE...PARTICULARLY THE RAP AND 00Z NAM SUGGEST
THAT THE BAND OF ISENTROPIC ASCENT CURRENTLY FEEDING THUNDERSTORMS
FROM SOUTHEAST KANSAS INTO MISSOURI WILL REMAIN FOCUSED OVER THE
AREA ALREADY SEEING TSTORM ACTIVITY. WHILE A FEW CELLS MAY DEVELOP
TO THE NORTH OF THE MAIN BAND OF ACTIVITY...THERE SEEMS TO BE
LIMITED INSTABILITY TO THE NORTH AND PERHAPS EVEN AN ELEVATED CAP
INHIBITING MORE ROBUST DEVELOPMENT. SO WITH THIS UPDATE HAVE KEPT
MOST THUNDERSTORM CHANCES SOUTH OF I-35 THROUGH AROUND 09Z...AND
USING THIS REASONING HAVE ALSO KEPT THE SEVERE THUNDERSTORM WATCH
SOUTH OF THE LOCAL FORECAST AREA FOR NOW.
HOWEVER...BY 08Z TO 10Z...EXPECT AN AREA OF LOW LEVEL MOISTURE
CURRENTLY EVIDENT OVER CENTRAL AND NORTH CENTRAL OKLAHOMA TO
STREAM NORTH ON THE NOSE OF AN INTENSIFYING LOW LEVEL JET. THIS
WARM MOIST AIRMASS WILL UNDERCUT SLIGHTLY STEEPER MID LEVEL LAPSE
RATES THAT ARE ADVECTING IN FROM SOUTHWEST KANSAS...EVIDENT ON THE
00Z DDC UPPER AIR SOUNDING. AS THIS WARM MOIST ADVECTION BECOMES
DEEP ENOUGH AND ISENTROPIC ASCENT IS ENHANCED WITHIN IT...AGAIN
PROBABLY IN THE 08Z TO 10Z TIME PERIOD...EXPECT SCATTERED
THUNDERSTORMS TO DEVELOP FROM SOUTH CENTRAL KANSAS NORTH INTO THE
EMPORIA AREA...AND EVENTUALLY FARTHER NORTH TOWARD THE I-70
CORRIDOR. MUCAPE INITIALLY SHOULD BE IN THE 400 TO 800 J/KG RANGE
WITH SOME INDICATIONS OF INCREASING CLOSER TO 1000 TO 1500 J/KG
AFTER SUNRISE. EFFECTIVE SHEAR ALOFT WILL BE QUITE STRONG AND WILL
SUPPORT STORM ORGANIZATION. IF THE STRONGER INSTABILITY COMES TO
FRUITION...COULD POTENTIALLY SEE A FEW STORMS PRODUCE SEVERE HAIL
MAINLY ALONG AND SOUTH OF I-70 AND PROBABLY AROUND SUNRISE OR
THEREAFTER. COULD BE A MARGINAL EVENT AS CONVECTIVE INTERACTIONS
MAY MITIGATE STORM STRENGTH. WILL HAVE TO MONITOR THE SITUATION
CLOSELY AS THE EVENING PROGRESSES REGARDING EVENTUAL SEVERE HAIL
POTENTIAL.
TO THE NORTH...AN AREA OF VERY LIGHT RAIN AND SNOW WAS EVIDENT ON
RADAR IN SOUTHERN NEBRASKA. THIS ACTIVITY SHOULD STAY NORTH OF THE
LOCAL FORECAST AREA BUT I SUPPOSE A SPRINKLE OR SNOWFLAKE WOULD
NOT BE COMPLETELY OUT OF THE QUESTION IN FAR NORTH CENTRAL KANSAS.
BARJENBRUCH
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 359 PM CDT MON APR 15 2013
FRONTAL BOUNDARY REMAINS SOUTH OF KANSAS ACROSS OKLAHOMA NORTHEAST
INTO MISSOURI AT 19Z. SOME CLEARING OF MID LEVEL DECK OCCURRING
ACROSS THE NORTH CENTRAL KANSAS COUNTIES WHILE SOLID OVERCAST
CONTINUES ACROSS EAST CENTRAL KANSAS. THE COMBINATION OF NORTHERLY
WINDS AND CLOUDS HAVE KEPT TEMPERATURES COOLER THAN EARLIER FORECAST
AND MADE ADJUSTMENTS DOWNWARD.
TONIGHT...ISENTROPIC LIFT OVER THE BOUNDARY WILL DEVELOP ELEVATED
SHOWERS AND SOME THUNDERSTORMS ACROSS THE AREA LATER TONIGHT.
PROFILERS ALREADY SHOWING SOUTHERLY 925MB-850MB WINDS IN EASTERN
OKLAHOMA. ISENTROPIC LIFT ON THE 300K SURFACE AND THE 305K SURFACE
INCREASES AFTER 06Z TONIGHT. BETTER ELEVATED INSTABILITY WILL BE
SOUTHEAST OF THE TURNPIKE. ELEVATED CAPE OF ONLY 100-200 J/KG
FORECAST OVERNIGHT. LOWS TONIGHT WILL COOL INTO THE MID 30S NORTH
CENTRAL TO THE MID 40S EAST CENTRAL.
SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE MORNING HOURS
THEN DECREASE SOME IN THE AFTERNOON. EML STRENGTHENS TUESDAY
AFTERNOON ACROSS THE AREA. HIGHS TUESDAY WILL ONLY BE IN THE UPPER
40S TO LOWER 50S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 359 PM CDT MON APR 15 2013
WARM AIR AND MOISTURE ADVECTION WILL DRAMATICALLY INCREASE TUESDAY
NIGHT AS A STRONG LLVL JET DEVELOPS. THIS WILL ESPECIALLY BE THE
CASE IN THE OVERNIGHT HOURS. ELEVATED CAPE WILL INCREASE INTO THE
1200-1800 J/KG RANGE ACROSS MUCH OF THE SOUTH COUNTY WARNING. WITH
DECREASING INHIBITION...EXPECT AT LEAST SCATTERED THUNDERSTORMS TO
DEVELOP WHICH COULD PRODUCE LARGE HAIL THROUGH SUNRISE ACROSS AREAS
GENERALLY ALONG AND SOUTH OF I 70 AS THE WARM FRONT REMAINS
GENERALLY SOUTH OF THE COUNTY WARNING AREA. MODELS SHOW CONSIDERABLE
DIFFERENCES IN THE TIMING OF THE STRONG UPPER LEVEL TROUGH COMING
OUT OF THE ROCKIES BY WEDNESDAY NIGHT AND HOW FAR THE WARM FRONT AND
SFC LOW DEVELOPS/MOVES. HAVE LEANED MORE TOWARDS A MORE SOUTHERLY
TRACK OF THE SFC LOW AND ASSOCIATED WARM FRONT WITH AN INVERTED
TROUGH EXTENDING NORTHEAST FROM THE LOW INTO THE CWA WEDNESDAY. AS
THE FLOW ALOFT INCREASES AND MOISTURE CONTINUES TO SURGE NORTHWARD
AS THE MAIN DYNAMICS OF THE SYSTEM ROTATE OUT INTO THE PLAINS EXPECT
MULTIPLE ROUNDS OF CONVECTION ACROSS MOST OF THE CWA TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT...SOME OF WHICH COULD PRODUCE LARGE
HAIL...ALTHOUGH STRONG WINDS WILL ALSO BE POSSIBLE AHEAD OF THE
ADVANCING TROUGH WEDNESDAY AND WEDNESDAY EVENING. LOCALLY HEAVY
RAINFALL AMOUNTS WILL ALSO BE POSSIBLE ESPECIALLY ACROSS THE
SOUTHEAST HALF OF THE CWA. FAVORED THE EC MODEL IN THE OUTER PERIODS
OF THIS SYSTEM AS IT EJECTS OUT INTO THE PLAINS THURSDAY WITH A RAIN
SNOW MIX POSSIBLE IN THE FAR NORTH CENTRAL COUNTIES LATE WEDNESDAY
NIGHT THEN ACROSS THE NORTHWEST HALF THURSDAY AND THE FAR NORTH
THURSDAY EVENING AS COLDER AIR SURGES IN WITHIN THE WRAPAROUND
MOISTURE FIELD ON THE BACKSIDE OF THE DEPARTING SYSTEM. DO NOT HAVE
HIGH ENOUGH CONFIDENCE TO GO ALL SNOW AT THIS POINT IN ANY ONE
LOCATION. THERE WILL BE A LARGE A DIFFICULT TO FORECAST TEMPERATURE
SPREAD ACROSS THE CWA WITH THE FRONT ON WEDNESDAY. FOR NOW WILL GO
WITH THE UPPER 40S NORTH CENTRAL TO NEAR 70 IN THE FAR SOUTHEAST
CORNER. TEMPERATURES WILL THEN FALL INTO THURSDAY WITH HIGHS FROM
THE UPPER 30S NORTH CENTRAL TO THE 40S ELSEWHERE.
THE MODELS ARE STILL IN AGREEMENT THAT AFTER THE DEEP TROUGH PASSES
THROUGH THE AREA THURSDAY...IT SHOULD BE DRY UNTIL THE PASSAGE OF
ANOTHER SHORTWAVE TROUGH OCCURS SUNDAY INTO MONDAY. THIS WILL BE THE
NEXT CHANCE FOR SHOWERS. HIGHS FOLLOWING THE THURSDAY SYSTEM WILL
REMAIN BELOW NORMAL WITH READINGS IN THE UPPER 40S AND LOW 50S
FRIDAY THEN THE 60S FOR SATURDAY INTO MONDAY. FROST AND OR FREEZING
TEMPERATURES REMAIN A CONCERN PRIMARILY FOR FRIDAY AND SATURDAY
MORNINGS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1203 AM CDT TUE APR 16 2013
VFR CONDITIONS ARE EXPECTED THROUGH AROUND 22Z. A WINDOW OF
THUNDERSTORM POTENTIAL EXISTS BETWEEN AROUND 10Z AND 18Z...WITH
BEST CHANCE FOR TS AT FOE/TOP. TS WILL BE SCATTERED IN NATURE AND
NOT PREDOMINANT...AND MAY STAY SOUTH OF TAF SITES SO DID NOT
INCLUDE TSRA IN THE TAF AT THIS TIME. IF STRONG STORMS MOVE
OVERHEAD...HAIL WILL BE POSSIBLE. MVFR CIGS SHOULD BUILD IN BY
LATE AFTERNOON/EVENING.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BARJENBRUCH
SHORT TERM...53
LONG TERM...63
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1116 PM CDT MON APR 15 2013
...UPDATED FORECAST FOR THUNDERSTORM EXPECTATIONS THROUGH MORNING...
.UPDATE...
ISSUED AT 1059 PM CDT MON APR 15 2013
LATEST MODEL GUIDANCE...PARTICULARLY THE RAP AND 00Z NAM SUGGEST
THAT THE BAND OF ISENTROPIC ASCENT CURRENTLY FEEDING THUNDERSTORMS
FROM SOUTHEAST KANSAS INTO MISSOURI WILL REMAIN FOCUSED OVER THE
AREA ALREADY SEEING TSTORM ACTIVITY. WHILE A FEW CELLS MAY DEVELOP
TO THE NORTH OF THE MAIN BAND OF ACTIVITY...THERE SEEMS TO BE
LIMITED INSTABILITY TO THE NORTH AND PERHAPS EVEN AN ELEVATED CAP
INHIBITING MORE ROBUST DEVELOPMENT. SO WITH THIS UPDATE HAVE KEPT
MOST THUNDERSTORM CHANCES SOUTH OF I-35 THROUGH AROUND 09Z...AND
USING THIS REASONING HAVE ALSO KEPT THE SEVERE THUNDERSTORM WATCH
SOUTH OF THE LOCAL FORECAST AREA FOR NOW.
HOWEVER...BY 08Z TO 10Z...EXPECT AN AREA OF LOW LEVEL MOISTURE
CURRENTLY EVIDENT OVER CENTRAL AND NORTH CENTRAL OKLAHOMA TO
STREAM NORTH ON THE NOSE OF AN INTENSIFYING LOW LEVEL JET. THIS
WARM MOIST AIRMASS WILL UNDERCUT SLIGHTLY STEEPER MID LEVEL LAPSE
RATES THAT ARE ADVECTING IN FROM SOUTHWEST KANSAS...EVIDENT ON THE
00Z DDC UPPER AIR SOUNDING. AS THIS WARM MOIST ADVECTION BECOMES
DEEP ENOUGH AND ISENTROPIC ASCENT IS ENHANCED WITHIN IT...AGAIN
PROBABLY IN THE 08Z TO 10Z TIME PERIOD...EXPECT SCATTERED
THUNDERSTORMS TO DEVELOP FROM SOUTH CENTRAL KANSAS NORTH INTO THE
EMPORIA AREA...AND EVENTUALLY FARTHER NORTH TOWARD THE I-70
CORRIDOR. MUCAPE INITIALLY SHOULD BE IN THE 400 TO 800 J/KG RANGE
WITH SOME INDICATIONS OF INCREASING CLOSER TO 1000 TO 1500 J/KG
AFTER SUNRISE. EFFECTIVE SHEAR ALOFT WILL BE QUITE STRONG AND WILL
SUPPORT STORM ORGANIZATION. IF THE STRONGER INSTABILITY COMES TO
FRUITION...COULD POTENTIALLY SEE A FEW STORMS PRODUCE SEVERE HAIL
MAINLY ALONG AND SOUTH OF I-70 AND PROBABLY AROUND SUNRISE OR
THEREAFTER. COULD BE A MARGINAL EVENT AS CONVECTIVE INTERACTIONS
MAY MITIGATE STORM STRENGTH. WILL HAVE TO MONITOR THE SITUATION
CLOSELY AS THE EVENING PROGRESSES REGARDING EVENTUAL SEVERE HAIL
POTENTIAL.
TO THE NORTH...AN AREA OF VERY LIGHT RAIN AND SNOW WAS EVIDENT ON
RADAR IN SOUTHERN NEBRASKA. THIS ACTIVITY SHOULD STAY NORTH OF THE
LOCAL FORECAST AREA BUT I SUPPOSE A SPRINKLE OR SNOWFLAKE WOULD
NOT BE COMPLETELY OUT OF THE QUESTION IN FAR NORTH CENTRAL KANSAS.
BARJENBRUCH
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 359 PM CDT MON APR 15 2013
FRONTAL BOUNDARY REMAINS SOUTH OF KANSAS ACROSS OKLAHOMA NORTHEAST
INTO MISSOURI AT 19Z. SOME CLEARING OF MID LEVEL DECK OCCURRING
ACROSS THE NORTH CENTRAL KANSAS COUNTIES WHILE SOLID OVERCAST
CONTINUES ACROSS EAST CENTRAL KANSAS. THE COMBINATION OF NORTHERLY
WINDS AND CLOUDS HAVE KEPT TEMPERATURES COOLER THAN EARLIER FORECAST
AND MADE ADJUSTMENTS DOWNWARD.
TONIGHT...ISENTROPIC LIFT OVER THE BOUNDARY WILL DEVELOP ELEVATED
SHOWERS AND SOME THUNDERSTORMS ACROSS THE AREA LATER TONIGHT.
PROFILERS ALREADY SHOWING SOUTHERLY 925MB-850MB WINDS IN EASTERN
OKLAHOMA. ISENTROPIC LIFT ON THE 300K SURFACE AND THE 305K SURFACE
INCREASES AFTER 06Z TONIGHT. BETTER ELEVATED INSTABILITY WILL BE
SOUTHEAST OF THE TURNPIKE. ELEVATED CAPE OF ONLY 100-200 J/KG
FORECAST OVERNIGHT. LOWS TONIGHT WILL COOL INTO THE MID 30S NORTH
CENTRAL TO THE MID 40S EAST CENTRAL.
SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE MORNING HOURS
THEN DECREASE SOME IN THE AFTERNOON. EML STRENGTHENS TUESDAY
AFTERNOON ACROSS THE AREA. HIGHS TUESDAY WILL ONLY BE IN THE UPPER
40S TO LOWER 50S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 359 PM CDT MON APR 15 2013
WARM AIR AND MOISTURE ADVECTION WILL DRAMATICALLY INCREASE TUESDAY
NIGHT AS A STRONG LLVL JET DEVELOPS. THIS WILL ESPECIALLY BE THE
CASE IN THE OVERNIGHT HOURS. ELEVATED CAPE WILL INCREASE INTO THE
1200-1800 J/KG RANGE ACROSS MUCH OF THE SOUTH COUNTY WARNING. WITH
DECREASING INHIBITION...EXPECT AT LEAST SCATTERED THUNDERSTORMS TO
DEVELOP WHICH COULD PRODUCE LARGE HAIL THROUGH SUNRISE ACROSS AREAS
GENERALLY ALONG AND SOUTH OF I 70 AS THE WARM FRONT REMAINS
GENERALLY SOUTH OF THE COUNTY WARNING AREA. MODELS SHOW CONSIDERABLE
DIFFERENCES IN THE TIMING OF THE STRONG UPPER LEVEL TROUGH COMING
OUT OF THE ROCKIES BY WEDNESDAY NIGHT AND HOW FAR THE WARM FRONT AND
SFC LOW DEVELOPS/MOVES. HAVE LEANED MORE TOWARDS A MORE SOUTHERLY
TRACK OF THE SFC LOW AND ASSOCIATED WARM FRONT WITH AN INVERTED
TROUGH EXTENDING NORTHEAST FROM THE LOW INTO THE CWA WEDNESDAY. AS
THE FLOW ALOFT INCREASES AND MOISTURE CONTINUES TO SURGE NORTHWARD
AS THE MAIN DYNAMICS OF THE SYSTEM ROTATE OUT INTO THE PLAINS EXPECT
MULTIPLE ROUNDS OF CONVECTION ACROSS MOST OF THE CWA TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT...SOME OF WHICH COULD PRODUCE LARGE
HAIL...ALTHOUGH STRONG WINDS WILL ALSO BE POSSIBLE AHEAD OF THE
ADVANCING TROUGH WEDNESDAY AND WEDNESDAY EVENING. LOCALLY HEAVY
RAINFALL AMOUNTS WILL ALSO BE POSSIBLE ESPECIALLY ACROSS THE
SOUTHEAST HALF OF THE CWA. FAVORED THE EC MODEL IN THE OUTER PERIODS
OF THIS SYSTEM AS IT EJECTS OUT INTO THE PLAINS THURSDAY WITH A RAIN
SNOW MIX POSSIBLE IN THE FAR NORTH CENTRAL COUNTIES LATE WEDNESDAY
NIGHT THEN ACROSS THE NORTHWEST HALF THURSDAY AND THE FAR NORTH
THURSDAY EVENING AS COLDER AIR SURGES IN WITHIN THE WRAPAROUND
MOISTURE FIELD ON THE BACKSIDE OF THE DEPARTING SYSTEM. DO NOT HAVE
HIGH ENOUGH CONFIDENCE TO GO ALL SNOW AT THIS POINT IN ANY ONE
LOCATION. THERE WILL BE A LARGE A DIFFICULT TO FORECAST TEMPERATURE
SPREAD ACROSS THE CWA WITH THE FRONT ON WEDNESDAY. FOR NOW WILL GO
WITH THE UPPER 40S NORTH CENTRAL TO NEAR 70 IN THE FAR SOUTHEAST
CORNER. TEMPERATURES WILL THEN FALL INTO THURSDAY WITH HIGHS FROM
THE UPPER 30S NORTH CENTRAL TO THE 40S ELSEWHERE.
THE MODELS ARE STILL IN AGREEMENT THAT AFTER THE DEEP TROUGH PASSES
THROUGH THE AREA THURSDAY...IT SHOULD BE DRY UNTIL THE PASSAGE OF
ANOTHER SHORTWAVE TROUGH OCCURS SUNDAY INTO MONDAY. THIS WILL BE THE
NEXT CHANCE FOR SHOWERS. HIGHS FOLLOWING THE THURSDAY SYSTEM WILL
REMAIN BELOW NORMAL WITH READINGS IN THE UPPER 40S AND LOW 50S
FRIDAY THEN THE 60S FOR SATURDAY INTO MONDAY. FROST AND OR FREEZING
TEMPERATURES REMAIN A CONCERN PRIMARILY FOR FRIDAY AND SATURDAY
MORNINGS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 626 PM CDT MON APR 15 2013
EXPECT VFR CONDITIONS THROUGH AT LEAST THE FIRST 12 HOURS OF THE
TAF...AND PROBABLY THROUGH 18Z. CIGS IN THE 4K TO 6K FOOT RANGE
WILL PERSIST THROUGH THE NIGHT INTO TUESDAY MORNING...BUT ARE
EXPECTED TO DECREASE TO AROUND 2500 FEET DURING THE AFTERNOON. TS
APPEAR POSSIBLE AFTER 10Z-12Z BUT SHOULD BE SCATTERED. TS WILL
INITIALLY COME CLOSE TO TOP/FOE...BUT EVENTUALLY TS CHANCES SPREAD
WEST TO MHK AS WELL. AT THIS TIME...IT APPEARS THAT SCATTERED TS
POSSIBLE ALMOST ANY TIME OF DAY ON TUESDAY.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BARJENBRUCH
SHORT TERM...53
LONG TERM...63
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
631 PM EDT TUE APR 16 2013
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS ARE LIKELY TODAY AND TONIGHT AS A COLD
FRONT SLIDES ACROSS THE REGION.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
JUST MADE A QUICK UPDATE TO BETTER REFLECT WARMING TEMPERATURES IN
THE LOCATIONS AHEAD OF THE COLD FRONT THAT ARE SEEING BREAKS IN
CLOUD COVER. ADJUSTED POP TIMING A LITTLE FOR THE OVERNIGHT HOURS
BASED ON THE MOST RECENT HRRR SINCE IT SEEMS TO BE REFLECTING THE
CURRENT SITUATION QUITE WELL. OTHERWISE...NO OTHER CHANGES.
PREVIOUS DISCUSSION FOLLOWS...
WHILE AMPLE CLOUD COVER HAS REMAINED ACROSS THE REGION
TODAY...SURFACE TEMPERATURES AND DEWOPINTS OUT AHEAD OF THE COLD
FRONT HAVE STILL REBOUNDED QUITE NICELY ALLOWING FOR AN INCREASE
IN CAPE TO NEAR 1000J/KG FOR SOUTHERN PORTIONS OF THE REGION. THIS
IS EXPECTED TO CONTINUE AND WHILE THE BETTER INSTABILITY AND SHEAR
CURRENTLY DO NOT LINE UP WELL...THIS COULD CHANGE AS ANOTHER
SHORTWAVE APPROACHES THE COLD FRONT AS IT GRADUALLY SAGS
SOUTHWARD. GIVEN THIS...CANNOT RULE OUT A FEW THUNDERSTORMS
MAINTAINING THEMSELVES TO SEVERE LEVELS. THUS...AFTER
COLLABORATION WITH SURROUNDING OFFICES AND THE STORM PREDICTION
CENTER...A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED THROUGH 11PM
THIS EVENING.
BASED ON THE MOST RECENT HRRR AND OTHER HI-RES MODELS...THE LINE
OF SHOWERS SHOULD REACH THE SOUTHERN HALF OF THE REGION OVERNIGHT
BEFORE THE BOUNDARY STALLS OVER SOMEWHERE ALONG THE MASON DIXON
LINE.
WARM NR TERM TEMPS WERE FORECAST USING A BLEND OF GUIDANCE AND THE
LATEST OBSERVATION TRENDS.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
STALLED FRONT WILL DRIFT NORTHWARD WED...BUT APPEARS TO ALMOST
WASH OUT AS RIDGES STRENGTHENS OVER THE UPPER OHIO VALLEY. THE
FRONT WILL BE FORCED NORTHWARD AS THE MAIN SFC LOW SWINGS OUT OF
THE SOUTHERN ROCKIES AND INTO THE SOUTHERN PLAINS. THE HEIGHT
RISES ARE IN RESPONSE TO A LARGE TROUGH WHICH WILL DIG INTO THE
ROCKIES. WILL INCLUDE THE CHC FOR SHOWERS AND STORMS WED AS AN
UPPER LEVEL WAVE WILL CREST THE TOP OF THE BUILDING RIDGE.
AREA WILL LIE IN THE WARM SECTOR BY WED NIGHT AND REMAIN THERE
THROUGH THU. EXPECT WED NIGHT TO REMAIN DRY WITH SCT SHOWERS/STORMS
POSSIBLE THU WITH DAYTIME HEATING.
UNDER SOUTHERLY FLOW...TEMPS WILL RISE ABOVE NORMAL ON THU.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A CDFNT SHOULD BE EXITING THE RGN FRI EVE...WITH ANY SHRA/TS CHCS
ENDG FRI NGT. AN UPR LVL TROF IS EXPD TO MOVE ACRS THE GT LKS RGN
SAT...BUT MOISTURE IS LMTD SO KEPT FCST DRY ATTM. HIGH PRES BLDS IN
SAT NGT THRU MON NGT UNTIL A CDFNT APRCHS FM THE W ON TUE WITH
ANOTHER CHC FOR SHRA/TS. TEMPS SHOULD BE BLO AVG LVLS OVR THE
WKEND...WITH A WRMG TREND ERLY NXT WK.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
COLD FRONT WILL MOVE ACROSS THE REGION THIS EVENING. THINK THAT A
BRIEF PERIOD OF TSRA REMAINS POSSIBLE WITH THE FRONT AS IT PASSES.
GUSTY SW WNDS LATE THIS AFTN SHOULD SHFT TO THE W AND THEN N THIS
EVE AFT FROPA. MVFR CIGS WILL REMAIN A POSSIBILITY AT FKL/DUJ INTO
THE EVE...OTRW GENL LOW END VFR CIGS FCST OUTSIDE OF ANY PCPN ACRS
THE RGN.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/...
THE FNT WL MOVE BACK N AS A WRMFNT WED NGT INTO THU WITH BRF RESTRNS
PSBL. A CDFNT WL MOVE E ACRS THE RGN FRI WITH SHRA/TS RESTRNS BEFORE
HI PRES BLDS IN SAT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
431 PM EDT TUE APR 16 2013
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS ARE LIKELY TODAY AND TONIGHT AS A COLD
FRONT SLIDES ACROSS THE REGION.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
WHILE AMPLE CLOUD COVER HAS REMAINED ACROSS THE REGION TODAY...SURFACE
TEMPERATURES AND DEWOPINTS OUT AHEAD OF THE COLD FRONT HAVE STILL
REBOUNDED QUITE NICELY ALLOWING FOR AN INCREASE IN CAPE TO NEAR
1000J/KG FOR SOUTHERN PORTIONS OF THE REGION. THIS IS EXPECTED TO
CONTINUE AND WHILE THE BETTER INSTABILITY AND SHEAR CURRENTLY DO
NOT LINE UP WELL...THIS COULD CHANGE AS ANOTHER SHORTWAVE
APPROACHES THE COLD FRONT AS IT GRADUALLY SAGS SOUTHWARD. GIVEN
THIS...CANNOT RULE OUT A FEW THUNDERSTORMS MAINTAINING THEMSELVES
TO SEVERE LEVELS. THUS...AFTER COLLABORATION WITH SURROUNDING
OFFICES AND THE STORM PREDICTION CENTER...A SEVERE THUNDERSTORM
WATCH HAS BEEN ISSUED THROUGH 11PM THIS EVENING.
BASED ON THE MOST RECENT HRRR AND OTHER HI-RES MODELS...THE LINE
OF SHOWERS SHOULD REACH THE SOUTHERN HALF OF THE REGION OVERNIGHT
BEFORE THE BOUNDARY STALLS OVER SOMEWHERE ALONG THE MASON DIXON
LINE.
WARM NR TERM TEMPS WERE FORECAST USING A BLEND OF GUIDANCE AND THE
LATEST OBSERVATION TRENDS.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
STALLED FRONT WILL DRIFT NORTHWARD WED...BUT APPEARS TO ALMOST
WASH OUT AS RIDGES STRENGTHENS OVER THE UPPER OHIO VALLEY. THE
FRONT WILL BE FORCED NORTHWARD AS THE MAIN SFC LOW SWINGS OUT OF
THE SOUTHERN ROCKIES AND INTO THE SOUTHERN PLAINS. THE HEIGHT
RISES ARE IN RESPONSE TO A LARGE TROUGH WHICH WILL DIG INTO THE
ROCKIES. WILL INCLUDE THE CHC FOR SHOWERS AND STORMS WED AS AN
UPPER LEVEL WAVE WILL CREST THE TOP OF THE BUILDING RIDGE.
AREA WILL LIE IN THE WARM SECTOR BY WED NIGHT AND REMAIN THERE
THROUGH THU. EXPECT WED NIGHT TO REMAIN DRY WITH SCT SHOWERS/STORMS
POSSIBLE THU WITH DAYTIME HEATING.
UNDER SOUTHERLY FLOW...TEMPS WILL RISE ABOVE NORMAL ON THU.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A CDFNT SHOULD BE EXITING THE RGN FRI EVE...WITH ANY SHRA/TS CHCS
ENDG FRI NGT. AN UPR LVL TROF IS EXPD TO MOVE ACRS THE GT LKS RGN
SAT...BUT MOISTURE IS LMTD SO KEPT FCST DRY ATTM. HIGH PRES BLDS IN
SAT NGT THRU MON NGT UNTIL A CDFNT APRCHS FM THE W ON TUE WITH
ANOTHER CHC FOR SHRA/TS. TEMPS SHOULD BE BLO AVG LVLS OVR THE
WKEND...WITH A WRMG TREND ERLY NXT WK.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
COLD FRONT WILL MOVE ACROSS THE REGION THIS EVENING. THINK THAT A
BRIEF PERIOD OF TSRA REMAINS POSSIBLE WITH THE FRONT AS IT PASSES.
GUSTY SW WNDS LATE THIS AFTN SHOULD SHFT TO THE W AND THEN N THIS
EVE AFT FROPA. MVFR CIGS WILL REMAIN A POSSIBILITY AT FKL/DUJ INTO
THE EVE...OTRW GENL LOW END VFR CIGS FCST OUTSIDE OF ANY PCPN ACRS
THE RGN.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/...
THE FNT WL MOVE BACK N AS A WRMFNT WED NGT INTO THU WITH BRF RESTRNS
PSBL. A CDFNT WL MOVE E ACRS THE RGN FRI WITH SHRA/TS RESTRNS BEFORE
HI PRES BLDS IN SAT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
211 PM EDT TUE APR 16 2013
.SYNOPSIS...
A WEAK FRONTAL BOUNDARY WILL CROSS JUST NORTH OF THE REGION
TONIGHT. OTHERWISE...HIGH PRESSURE BECOMES CENTERED OFF THE MID
ATLANTIC COAST FOR MOST OF THIS WEEK. A MORE VIGOROUS COLD FRONT
WILL IMPACT THE AREA FRIDAY INTO SATURDAY..
&&
.NEAR TERM /THROUGH TONIGHT/...
OVERALL CONDITIONS IMPROVE AS CLOUDY SKIES THIS MORNING BREAK UP
DURING THIS AFTN AND TEMPS WARM TOWARD 70-75 DEGREES AREAWIDE...EXCEPT AT
THE BEACHES WHERE TEMPS WILL BE IN THE 60S DUE TO PERSISTENT
ONSHORE FLOW. THE LOCAL WRF AND THE RAP MODELS ALL SHOW THE
MOISTURE SLOW TO MIX OUT IN THE WEST IN THE 925 TO 850 MB LAYER.
THEY DO SHOW THAT LEVEL WINDS SLOWLY MOVING TO SOUTHWEST AND
DRYING DEVELOPING. WILL ALSO KEEP TEMPERATURES COOLER IN THE WEST
INITIALLY WITH MORE CLOUD COVER. FOR TONIGHT...A COLD FRONT
PASSES ACROSS NEW ENGLAND AND WILL DRAG A WEAK BOUNDARY ACROSS
NWRN PORTIONS OF THE FA OVERNIGHT. THIS FEATURE WILL BRING
INCREASED CLOUDS TO THIS AREA WITH PARTLY CLOUDY SKIES FARTHER TO
THE SE. LOW TEMPS WILL RUN ABOUT 5 DEGREES ABOVE NORMAL AS CLOUD
COVER INSULATES THE ATMOSPHERE TONIGHT. EXPECT LOWS IN THE MID TO
UPPER 50S REGIONWIDE (LOW TO MID 50S IMMEDIATE COAST).
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
WED/WED NIGHT...RELATIVELY FLAT UPPER LEVEL RIDGING AND SW FLOW
OVER THE TN VALLEY AND SPINE OF THE APPALACHIANS WILL ALLOW
MOISTURE AND WEAK SHORTWAVE ENERGY TO MOVE AROUND THE PERIPHERY OF
THE UPPER RIDGE DURING THE AFTN/EVENING. THE DEVELOPMENT OF A LEE
TROUGH IS ALSO POSSIBLE AS THE FRONT FROM TUE NIGHT STALLS ACROSS
SE VA/NE NC. UNLIKE MOST LEE TROUGHS THAT TEND TO DEVELOP OVER THE
ERN PIEDMONT...THIS ONE IS EXPECTED TO TAKE ON MORE OF A
POSITIVELY TILTED ORIENTATION (ENE TO WSW). INCREASING TEMPS AND
DEWPOINTS DURING THE DAY WILL CREATE ENOUGH LOW-LEVEL INSTABILITY
FOR LIGHT SHOWERS TO BE POSSIBLE NORTH OF THE TROUGH AXIS.
HOWEVER...WEAK DYNAMICS AND VERY LIGHT WINDS BELOW 500 MB WILL
LIMIT THUNDER POTENTIAL TO A SLIGHT CHANCE IN THE AFTN/EVENING.
EXPECT A NICE WARM-UP WITH HIGHS IN THE LOWER 80S FOR MOST
AREAS...IN THE MID-UPPER 70S FOR THE IMMEDIATE COAST...AND IN THE
UPPER 60S NEAR OCEAN CITY MD. ANY SHOWERS THAT DEVELOP SHOULD
DISSIPATE QUICKLY AROUND SUNSET DUE TO THE LOSS OF DAYTIME HEATING
AND BECAUSE OF THE WEAK DYNAMICS ALREADY PRESENT. MOSTLY CLOUDY
SKIES WILL ONCE AGAIN HAMPER LOW TEMPS FROM DROPPING TO THEIR FULL
POTENTIAL. LOWS SHOULD GENERALLY BE AROUND 60 (MID-UPPER 50S
IMMEDIATE COAST).
THU/THU NIGHT...THE MID AND UPPER LEVEL RIDGE AXES MOVE OFFSHORE ON
THU. SW FLOW ALOFT WILL RESULT IN WAA TAKING PLACE THUS ALLOWING
HIGH TEMPS TO WARM A FEW MORE DEGREES AS COMPARED TO WED. AN
APPROACHING COLD FRONT MOVING ACROSS THE CTRL U.S. WILL CAUSE THE
SFC PRESSURE GRADIENT TO TIGHTEN...THEREFORE GUSTS OF 20-25 MPH ARE
ANTICIPATED DURING THE AFTN. ASIDE FROM BREEZY CONDITIONS...THU
WILL BE A RATHER NICE DAY ACROSS THE AREA. THE VIGOROUS COLD FRONT
CONTINUES TO DIG INTO THE MIDWEST THU NIGHT...ACTING TO SLOW ITS
EWD PROGRESSION INTO THE MID ATLANTIC REGION. SFC WINDS WILL
BECOME MORE SLY THU NIGHT AND REINFORCE ONGOING WAA PROCESSES. THE
COMBINATION OF WAA AND INCREASING HIGH CLOUDS FROM THE APPROACHING
SYSTEM WILL ALLOW LOW TEMPS TO RUN ABOUT 10-15 DEGREES ABOVE
SEASONAL NORMALS. LOWS SHOULD GENERALLY BE IN THE LOWER 60S (55 TO
60 IMMEDIATE COAST).
FRI...THE APPROACHING (AND VIGOROUS) COLD FRONT WILL CONTINUE TO
APPROACH THE MID ATLANTIC REGION ON FRI. SLY SFC WINDS WILL INCREASE
FURTHER WITH GUSTS OF 25-30 MPH LIKELY AS THE PRESSURE GRADIENT
TIGHTENS EVEN MORE. THERE ARE SOME INDICATIONS THAT PRECIPITATION
GENERATION MAY NOT OCCUR UNTIL FRI AFTN...BUT HAVE KEPT THE
MORNING FORECAST INTACT FOR NOW WITH CHC SHOWERS FOR THE ERN
PIEDMONT AND SCHC SHOWERS AS FAR AS THE MID ATLANTIC COAST. FOR
THE AFTN...LEE TROUGH DEVELOPMENT IS ANTICIPATED DUE TO
TEMPERATURE DIFFERENCES AHEAD OF AND BEHIND THE FRONT. ALSO...
ISENTROPIC SFCS INDICATE 40-50 KT OF SW FLOW WITH THE BEST
MOISTURE IN THE PIEDMONT DURING THE AFTN. DUE TO THE SLOWER NATURE
OF DIGGING SYSTEMS...THE FRONT SHOULD BE DELAYED AND BEST PRECIP
CHANCES SHOULD OCCUR IN THE PIEDMONT THU AFTN ALONG THE LEE TROUGH
AXIS WITH MORE SHOWERS DEVELOPING FARTHER EAST DURING THE EVENING.
FAVORABLE THERMAL PROFILES AND UNIDIRECTIONAL WIND SHEAR...IN
ADDITION TO DYNAMIC SUPPORT ALOFT...WILL SUPPORT THUNDERSTORMS
WITH THE POTENTIAL FOR DAMAGING WIND GUSTS ON FRI AFTN INTO FRI
NIGHT. PWATS ARE ALSO PROGGED TO REACH 1.50 INCHES WHICH WILL
RESULT IN MODERATE TO HEAVY RAINFALL. THIS SYSTEM BEARS CLOSE
MONITORING SINCE IT IS TOO EARLY TO NARROW DOWN THE FINER DETAILS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
WILL INCREASE POPS QUICKLY FROM WEST TO EAST BY FRIDAY EVENING
INTO SATURDAY MORNING AS THE FRONT MOVES THROUGH. EXPECTING
THE PRECIP TO END ACROSS THE LOCAL AREA SATURDAY AFTERNOON. LOWS
FRIDAY NIGHT MAINLY IN THE 50S. COOLER SATURDAY WITH HIGHS IN THE
60S. HIGH PRESSURE BRIEFLY BUILDS IN SUNDAY FOR DRY WX. THERE IS
THE POSSIBILITY OF INCREASED ONSHORE FLOW NEXT MONDAY WITH A
COASTAL FRONT/INVERTED TROUGH BACKING INTO THE AREA. WILL
ADVERTISE SOME LOW POPS BY NEXT MONDAY FOR NOW AND KEEPS HIGH
TEMPS IN THE 60S NEXT SUNDAY/MONDAY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
TAF SITES WILL HAVE BKN/OVC CIGS 4 TO 7K FT AGL WITH SOME
POTENTIAL LOWERING TO MVFR LEVELS (3K FT AGL) IN WESTERN PORTIONS
OF THE CWA. HIGH PRESSURE MOVES BACK INTO THE REGION WITH LOW LEVEL
MOISTURE BRINGING A CHANCE FOR PATCHY FOG/LOW CIGS BY EARLY WED
MORNING. ISOLATED TO WIDELY SCATTERED SHRA/TSRA WILL BE POSSIBLE
WED LATE AFTN/EARLY EVENING (GREATEST CHC FOR THIS AT KRIC).
COULD AGAIN SEE SOME PATCHY FOG/LOW CLOUDS EARLY THU.
OTHERWISE...MAINLY VFR UNTIL THE FRONT ARRIVES FRI AFTN INTO EARLY
SAT...BRINGING NUMEROUS SHRA/ISOLATED TO SCATTERED TSRA AND A
PERIOD OF IFR CONDITIONS.
&&
.MARINE...
HAVE ADDED A FEW MORE ZONES INTO THE SCA HEADLINES...AS SEAS REMAIN
6-8 FT ACRS SE VA AND NE NC COASTAL WATERS (3-4 FT AT THE MOUTH OF
THE BAY)...AND ARE SLOWLY INCREASING FARTHER NORTH. FOR COASTAL
WATERS N OF PARRAMORE WILL START THE SCA BY 7 AM...AND SEAS SHOULD
AVG 4-6 FT ACRS THESE AREAS THROUGH THE EVENING. WHILE MUCH OF THIS
IS DUE TO SWELL RATHER THAN WIND HAVE DECIDED TO KEEP IT SMALL CRAFT
ADVSY AS OPPOSED TO SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS TO AVOID
CONFUSION W/ MULTIPLE HEADLINES.
OTHERWISE...WEAK LOW PRESSURE IS STILL SITUATED OFF THE SC COAST
WITH HIGH PRESSURE CENTERED OFF THE NEW ENGLAND COAST AND THE
RESULTANT FLOW BETWEEN THESE TWO FEATURES CONTINUES TO PRODUCE E/SE
WINDS. WIND SPEEDS TODAY ARE NOT EXPECTED TO GET MUCH ABOVE 15 KT SO
DO NOT ANTICIPATE ANY HEADLINES OUTSIDE OF THE COASTAL WATERS AND
MOUTH OF THE BAY FOR TODAY. IT MAY BE CLOSE IN THE BAY BY THIS
EVENING AS SE FLOW INCREASES SOMEWHAT AS IT OFTEN DOES IN THE
EVENING (WHILE THEY WEAKEN OVER LAND). FOR NOW HAVE KEPT THEM CAPPED
AT 15 KT. WINDS WILL THEN TURN MORE TO SW OVERNIGHT BEFORE BECOMING
RATHER LIGHT ON WED. THIS SHOULD ALLOW SEAS TO SUBSIDE BELOW 5 FT.
WINDS INCREASE ON THU...AND ESPECIALLY THU NIGHT THROUGH FRI AS
PRESSURE GRADIENT TIGHTENS UP AHEAD OF THE APPROACHING COLD FRONT.
SCA CONDITIONS ARE LIKELY THU NIGHT THROUGH FRI NIGHT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR ANZ634-
654-656-658.
SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ650-
652.
&&
$$
SYNOPSIS...BMD
NEAR TERM...BMD/JAB
SHORT TERM...BMD
LONG TERM...JDM
AVIATION...LKB/DAP
MARINE...LKB
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1008 AM EDT TUE APR 16 2013
.SYNOPSIS...
A WEAK FRONTAL BOUNDARY WILL CROSS JUST NORTH OF THE REGION
TONIGHT. OTHERWISE...HIGH PRESSURE BECOMES CENTERED OFF THE MID
ATLANTIC COAST FOR MOST OF THIS WEEK. A MORE VIGOROUS COLD FRONT
WILL IMPACT THE AREA FRIDAY INTO SATURDAY..
&&
.NEAR TERM /THROUGH TONIGHT/...
OVERALL CONDITIONS IMPROVE AS CLOUDY SKIES THIS MORNING BREAK UP
DURING THIS AFTN AND TEMPS WARM TOWARD 70-75 DEGREES AREAWIDE...EXCEPT AT
THE BEACHES WHERE TEMPS WILL BE IN THE 60S DUE TO PERSISTENT
ONSHORE FLOW. THE LOCAL WRF AND THE RAP MODELS ALL SHOW THE
MOISTURE SLOW TO MIX OUT IN THE WEST IN THE 925 TO 850 MB LAYER.
THEY DO SHOW THAT LEVEL WINDS SLOWLY MOVING TO SOUTHWEST AND
DRYING DEVELOPING. WILL ALSO KEEP TEMPERATURES COOLER IN THE WEST
INITIALLY WITH MORE CLOUD COVER. FOR TONIGHT...A COLD FRONT
PASSES ACROSS NEW ENGLAND AND WILL DRAG A WEAK BOUNDARY ACROSS
NWRN PORTIONS OF THE FA OVERNIGHT. THIS FEATURE WILL BRING
INCREASED CLOUDS TO THIS AREA WITH PARTLY CLOUDY SKIES FARTHER TO
THE SE. LOW TEMPS WILL RUN ABOUT 5 DEGREES ABOVE NORMAL AS CLOUD
COVER INSULATES THE ATMOSPHERE TONIGHT. EXPECT LOWS IN THE MID TO
UPPER 50S REGIONWIDE (LOW TO MID 50S IMMEDIATE COAST).
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
WED/WED NIGHT...RELATIVELY FLAT UPPER LEVEL RIDGING AND SW FLOW
OVER THE TN VALLEY AND SPINE OF THE APPALACHIANS WILL ALLOW
MOISTURE AND WEAK SHORTWAVE ENERGY TO MOVE AROUND THE PERIPHERY OF
THE UPPER RIDGE DURING THE AFTN/EVENING. THE DEVELOPMENT OF A LEE
TROUGH IS ALSO POSSIBLE AS THE FRONT FROM TUE NIGHT STALLS ACROSS
SE VA/NE NC. UNLIKE MOST LEE TROUGHS THAT TEND TO DEVELOP OVER THE
ERN PIEDMONT...THIS ONE IS EXPECTED TO TAKE ON MORE OF A
POSITIVELY TILTED ORIENTATION (ENE TO WSW). INCREASING TEMPS AND
DEWPOINTS DURING THE DAY WILL CREATE ENOUGH LOW-LEVEL INSTABILITY
FOR LIGHT SHOWERS TO BE POSSIBLE NORTH OF THE TROUGH AXIS.
HOWEVER...WEAK DYNAMICS AND VERY LIGHT WINDS BELOW 500 MB WILL
LIMIT THUNDER POTENTIAL TO A SLIGHT CHANCE IN THE AFTN/EVENING.
EXPECT A NICE WARM-UP WITH HIGHS IN THE LOWER 80S FOR MOST
AREAS...IN THE MID-UPPER 70S FOR THE IMMEDIATE COAST...AND IN THE
UPPER 60S NEAR OCEAN CITY MD. ANY SHOWERS THAT DEVELOP SHOULD
DISSIPATE QUICKLY AROUND SUNSET DUE TO THE LOSS OF DAYTIME HEATING
AND BECAUSE OF THE WEAK DYNAMICS ALREADY PRESENT. MOSTLY CLOUDY
SKIES WILL ONCE AGAIN HAMPER LOW TEMPS FROM DROPPING TO THEIR FULL
POTENTIAL. LOWS SHOULD GENERALLY BE AROUND 60 (MID-UPPER 50S
IMMEDIATE COAST).
THU/THU NIGHT...THE MID AND UPPER LEVEL RIDGE AXES MOVE OFFSHORE ON
THU. SW FLOW ALOFT WILL RESULT IN WAA TAKING PLACE THUS ALLOWING
HIGH TEMPS TO WARM A FEW MORE DEGREES AS COMPARED TO WED. AN
APPROACHING COLD FRONT MOVING ACROSS THE CTRL U.S. WILL CAUSE THE
SFC PRESSURE GRADIENT TO TIGHTEN...THEREFORE GUSTS OF 20-25 MPH ARE
ANTICIPATED DURING THE AFTN. ASIDE FROM BREEZY CONDITIONS...THU
WILL BE A RATHER NICE DAY ACROSS THE AREA. THE VIGOROUS COLD FRONT
CONTINUES TO DIG INTO THE MIDWEST THU NIGHT...ACTING TO SLOW ITS
EWD PROGRESSION INTO THE MID ATLANTIC REGION. SFC WINDS WILL
BECOME MORE SLY THU NIGHT AND REINFORCE ONGOING WAA PROCESSES. THE
COMBINATION OF WAA AND INCREASING HIGH CLOUDS FROM THE APPROACHING
SYSTEM WILL ALLOW LOW TEMPS TO RUN ABOUT 10-15 DEGREES ABOVE
SEASONAL NORMALS. LOWS SHOULD GENERALLY BE IN THE LOWER 60S (55 TO
60 IMMEDIATE COAST).
FRI...THE APPROACHING (AND VIGOROUS) COLD FRONT WILL CONTINUE TO
APPROACH THE MID ATLANTIC REGION ON FRI. SLY SFC WINDS WILL INCREASE
FURTHER WITH GUSTS OF 25-30 MPH LIKELY AS THE PRESSURE GRADIENT
TIGHTENS EVEN MORE. THERE ARE SOME INDICATIONS THAT PRECIPITATION
GENERATION MAY NOT OCCUR UNTIL FRI AFTN...BUT HAVE KEPT THE
MORNING FORECAST INTACT FOR NOW WITH CHC SHOWERS FOR THE ERN
PIEDMONT AND SCHC SHOWERS AS FAR AS THE MID ATLANTIC COAST. FOR
THE AFTN...LEE TROUGH DEVELOPMENT IS ANTICIPATED DUE TO
TEMPERATURE DIFFERENCES AHEAD OF AND BEHIND THE FRONT. ALSO...
ISENTROPIC SFCS INDICATE 40-50 KT OF SW FLOW WITH THE BEST
MOISTURE IN THE PIEDMONT DURING THE AFTN. DUE TO THE SLOWER NATURE
OF DIGGING SYSTEMS...THE FRONT SHOULD BE DELAYED AND BEST PRECIP
CHANCES SHOULD OCCUR IN THE PIEDMONT THU AFTN ALONG THE LEE TROUGH
AXIS WITH MORE SHOWERS DEVELOPING FARTHER EAST DURING THE EVENING.
FAVORABLE THERMAL PROFILES AND UNIDIRECTIONAL WIND SHEAR...IN
ADDITION TO DYNAMIC SUPPORT ALOFT...WILL SUPPORT THUNDERSTORMS
WITH THE POTENTIAL FOR DAMAGING WIND GUSTS ON FRI AFTN INTO FRI
NIGHT. PWATS ARE ALSO PROGGED TO REACH 1.50 INCHES WHICH WILL
RESULT IN MODERATE TO HEAVY RAINFALL. THIS SYSTEM BEARS CLOSE
MONITORING SINCE IT IS TOO EARLY TO NARROW DOWN THE FINER DETAILS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
WILL INCREASE POPS QUICKLY FROM WEST TO EAST BY FRIDAY EVENING
INTO SATURDAY MORNING AS THE FRONT MOVES THROUGH. EXPECTING
THE PRECIP TO END ACROSS THE LOCAL AREA SATURDAY AFTERNOON. LOWS
FRIDAY NIGHT MAINLY IN THE 50S. COOLER SATURDAY WITH HIGHS IN THE
60S. HIGH PRESSURE BRIEFLY BUILDS IN SUNDAY FOR DRY WX. THERE IS
THE POSSIBILITY OF INCREASED ONSHORE FLOW NEXT MONDAY WITH A
COASTAL FRONT/INVERTED TROUGH BACKING INTO THE AREA. WILL
ADVERTISE SOME LOW POPS BY NEXT MONDAY FOR NOW AND KEEPS HIGH
TEMPS IN THE 60S NEXT SUNDAY/MONDAY.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
E/SE ONSHORE FLOW PREVAILS EARLY THIS MORNING...WITH VARIABLY
CLOUDY SKIES ACRS THE AREA. IN GENERAL...TAF SITES WILL HAVE
BKN/OVC CIGS 4 TO 7K FT AGL WITH SOME POTENTIAL LOWERING TO MVFR
LEVELS (2-3K FT AGL) BETWEEN 09-12Z. MODELS STRUGGLING TO HANDLE
ONSHORE FLOW AND POSSIBLE IFR CIGS OVER THE REGION. THE HIGHEST
CONFIDENCE FOR IFR CIGS EXPECTED TO REMAIN OVER THE PIEDMONT WWD
INTO THE BLUE RIDGE AND HIGHER TERRAIN (WHICH WOULD NOT AFFECT TAF
SITES). SOME PATCHY FOG WILL BE POSSIBLE INLAND IF SKIES CLEAR
OUT...BUT THIS LOOKS TO BE UNLIKELY AT KRIC SO WILL NOT HAVE ANY
MVFR/IFR VSBYS.
OVERALL CONDITIONS IMPROVE TODAY AS HIGH PRESSURE MOVES BACK INTO
THE REGION THROUGH WED NIGHT. LOW LEVEL MOISTURE WILL BRING AT
LEAST A LOW CHANCE FOR PATCHY FOG/LOW CIGS BY EARLY WED
MORNING...WITH ISOLATED TO WIDELY SCATTERED SHRA/TSRA POSSIBLE WED
LATE AFTN/EARLY EVENING (GREATEST CHC FOR THIS AT KRIC). COULD
AGAIN SEE SOME PATCHY FOG/LOW CLOUDS EARLY THU. OTHERWISE...MAINLY
VFR UNTIL THE FRONT ARRIVES FRI AFTN INTO EARLY SAT...BRINGING
NUMEROUS SHRA/ISOLATED TO SCATTERED TSRA AND A PERIOD OF IFR
CONDITIONS.
&&
.MARINE...
HAVE ADDED A FEW MORE ZONES INTO THE SCA HEADLINES...AS SEAS REMAIN
6-8 FT ACRS SE VA AND NE NC COASTAL WATERS (3-4 FT AT THE MOUTH OF
THE BAY)...AND ARE SLOWLY INCREASING FARTHER NORTH. FOR COASTAL
WATERS N OF PARRAMORE WILL START THE SCA BY 7 AM...AND SEAS SHOULD
AVG 4-6 FT ACRS THESE AREAS THROUGH THE EVENING. WHILE MUCH OF THIS
IS DUE TO SWELL RATHER THAN WIND HAVE DECIDED TO KEEP IT SMALL CRAFT
ADVSY AS OPPOSED TO SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS TO AVOID
CONFUSION W/ MULTIPLE HEADLINES.
OTHERWISE...WEAK LOW PRESSURE IS STILL SITUATED OFF THE SC COAST
WITH HIGH PRESSURE CENTERED OFF THE NEW ENGLAND COAST AND THE
RESULTANT FLOW BETWEEN THESE TWO FEATURES CONTINUES TO PRODUCE E/SE
WINDS. WIND SPEEDS TODAY ARE NOT EXPECTED TO GET MUCH ABOVE 15 KT SO
DO NOT ANTICIPATE ANY HEADLINES OUTSIDE OF THE COASTAL WATERS AND
MOUTH OF THE BAY FOR TODAY. IT MAY BE CLOSE IN THE BAY BY THIS
EVENING AS SE FLOW INCREASES SOMEWHAT AS IT OFTEN DOES IN THE
EVENING (WHILE THEY WEAKEN OVER LAND). FOR NOW HAVE KEPT THEM CAPPED
AT 15 KT. WINDS WILL THEN TURN MORE TO SW OVERNIGHT BEFORE BECOMING
RATHER LIGHT ON WED. THIS SHOULD ALLOW SEAS TO SUBSIDE BELOW 5 FT.
WINDS INCREASE ON THU...AND ESPECIALLY THU NIGHT THROUGH FRI AS
PRESSURE GRADIENT TIGHTENS UP AHEAD OF THE APPROACHING COLD FRONT.
SCA CONDITIONS ARE LIKELY THU NIGHT THROUGH FRI NIGHT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR ANZ634-
654-656-658.
SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ650-
652.
&&
$$
SYNOPSIS...BMD
NEAR TERM...BMD/JAB
SHORT TERM...BMD
LONG TERM...JDM
AVIATION...LKB
MARINE...LKB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
437 PM EDT TUE APR 16 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 436 PM EDT TUE APR 16 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NRN QUEBEC THROUGH JAMES BAY INTO NRN ONTARIO WAS DEPARTING TO THE
EAST. UPSTREAM...SW FLOW PREVAILED THROUGH THE PLAINS AHEAD OF A
TROUGH FROM THE NRN ROCKIES THROUGH THE GREAT BASIN. WITH CONFLUENT
FLOW WITH QVECTOR DIV AND SUBSIDENCE OVER THE NRN GREAT LAKES...THE
SCT FLURRIES HAD DIMINISHED THIS AFTERNOON.
AS HIGH PRES BUILDS INTO NRN ONTARIO TONIGHT BRINGING ENE ACYC FLOW
INTO UPPER MI AND DAYTIME HEATING FADES...EXPECT THAT WINDS WILL
DIMINISH AND CLOUDS WILL THIN OUT ENOUGH FOR TEMPS TO DROP INTO THE
20S.
AS THE WRN TROUGH EDGES TO THE EAST AND A SFC-850 MB TROUGH DEVELOPS
FROM THE SRN PLAINS INTO THE UPPER MS VALLEY...WAA AND MOISTURE
ADVECTION WILL INCREASE QUICKLY BY WED AFTERNOON. THE INITIAL AREA
OF PCPN IS EXPECTED INTO THE WEST...WHERE 295K-300K ISENTROPIC LIFT
IS STRONGEST. GIVEN THE DRY ERLY FLOW AS THE HIGH GRADUALLY MOVES
EAST THROUGH NRN ONTARIO...THE SLOWER PROGRESSION OF PCPN INTO
UPPER...PER NAM...WAS PREFERRED COMPARED TO THE GFS/ECMWF. EXPECT
ENOUGH OF A LINGERING WARM LOWER LAYER FOR MOSTLY RAIN AT THE ONSET
OF MAINLY LIGHT PCPN AS AFTERNOON TEMPS CLIMB INTO THE 40F TO 45F
RANGE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 436 PM EDT TUE APR 16 2013
MAIN ATTENTION FOR THE LONG TERM PORTION OF THE FORECAST ARE THE
TWO WAVES OF PRECIPITATION ASSOCIATED WITH ENERGY AND LOW PRESSURE
SYSTEMS EXITING FROM THE UPPER TROUGH CURRENTLY MOVING THROUGH THE
WESTERN CONUS.
FIRST WAVE WILL BE INFLUENCING THE AREA AT THE START OF THE LONG
TERM PERIOD WILL BE ASSOCIATED WITH SHORTWAVE ENERGY EJECTING AHEAD
OF THE TROUGH EXPECTED TO BE IN THE CENTRAL ROCKIES. AT THE
SURFACE...A LOW CENTERED IN WESTERN OKLAHOMA AND THE
PANHANDLE OF TEXAS WILL BEGIN ELONGATING A TROUGH NORTHEAST INT HE
MID MISSISSIPPI VALLEY ON WEDNESDAY AFTERNOON AND THEN NORTHEAST
INTO NORTHERN LAKE MICHIGAN BY 12Z THURSDAY. WITH THE STRONG MID
LEVEL FORCING ASSOCIATED WITH 925-700MB WARM AIR ADVECTION AND
LIKELY CONVECTION ON THE EAST SIDE OF THE TROUGH...WOULD EXPECT THE
HEAVIEST PRECIPITATION TO BE JUST TO THE SOUTHEAST OF THE CWA OR
BRUSH THE SOUTHEAST PART OF THE CWA. BUT...WITH THE AREA UNDER THE
RIGHT REAR OF THE UPPER JET AND ENOUGH OVERRIDING FLOW WITH THAT
WARM AIR ADVECTION AND ISENTROPIC ASCENT ON THE 280-300K
SFCS...STILL THINK THAT THERE WILL BE ENOUGH FORCING FOR MODERATE
PRECIPITATION ACROSS MUCH OF THE CWA. GENERAL MODEL CONSENSUS OF
0.50-0.80 INCH SEEMS REASONABLE FOR MUCH OF THE AREA...WITH VALUES
APPROACHING AN INCH ALONG THE LAKE MICHIGAN SHORELINE. THIS TRICKY
PART OF THIS FORECAST IS WHAT AMOUNT OF THE PRECIP WILL FALL AS
RAIN OVER THE WESTERN HALF OF THE CWA DUE TO THE ELEVATED WARM
LAYER. THERE CONTINUES TO BE SOME DISCREPANCY IN THE AMOUNT OF WARM
AIR THAT MOVES OVER THE CENTRAL CWA AND HOW FAR WEST THAT MOVES.
THINK THE FAR WESTERN CWA WILL LIKELY SEE MAINLY SNOW /FROM
KCMX TO KIWD/...BUT COULD SEE A BRIEF PERIOD OF FREEZING RAIN
OVERNIGHT. THE AREA BETWEEN THERE AND A LINE FROM MARQUETTE TO IRON
MOUNTAIN IS THE TRICKY AREA...SINCE THERE WILL LIKELY BE ENOUGH
WARM AIR TO MELT THE SNOW ALOFT. THEN PRECIP TYPE COMES DOWN TO
SURFACE TEMPERATURES...SINCE 925MB TEMPS ARE WELL BELOW FREEZING.
WILL CONTINUE TO MENTION MAINLY FREEZING RAIN IN THAT AREA...WITH
SOME MENTION OF SNOW. ALL IN ALL...APPEARS THAT THIS WILL LIKELY BE
A SOLID ADVISORY FOR THE WESTERN HALF OF THE CWA AND THERE IS SOME
CONCERN FOR DECENT ICE ACCUMULATION DEPENDING ON WHAT THE SURFACE
TEMPS ARE. THIS ENERGY WILL SHIFT NORTHEAST ON THURSDAY MORNING AND
WITH THE 850MB FLOW BECOMING MORE SOUTHWEST...WOULD EXPECT THE
PRECIPITATION TO WEAKEN HEADING INTO THE AFTERNOON.
NEXT SYSTEM TO AFFECT THE AREA WILL BE AS THE UPPER TROUGH LIFTS TO
THE NORTHEAST AND MOVES TOWARDS THE UPPER GREAT LAKES ON THURSDAY
NIGHT INTO FRIDAY. THIS WILL INTENSIFY A LOW ALONG THE LINGERING
SURFACE TROUGH AND THEN LIKELY TRACK TOWARDS THE STRAITS OF
MACKINAC BY 12Z FRIDAY. THE MAIN CONCERN FOR WIDESPREAD
PRECIPITATION FOR THE AREA IS THE TRACK/LOCATION OF THE DRY SLOT
SURGING NORTHEAST ON THURSDAY NIGHT INTO FRIDAY. THERE ARE STILL
SOME DIFFERENCES IN THE LOW TRACK WITH THE NAM/GEM...SO OPTED TO
FOLLOW THE MORE CONSISTENT IDEA OF THE GFS/ECMWF FOR THE FORECAST.
LATEST INDICATIONS IN THE MODELS THAT THE DRY SLOT WILL AFFECT THE
CENTRAL/EASTERN CWA...BETWEEN THE DEFORMATION PRECIPITATION
AFFECTING THE WESTERN CWA AND THE CONVECTION AND HEAVY RAIN
AFFECTING LOWER MICHIGAN AHEAD OF THE COLD FRONT. THUS...WOULD
EXPECT THE HEAVIEST PRECIPITATION TO OCCUR OVER THE WESTERN THIRD OF
THE CWA THURSDAY NIGHT INTO FRIDAY...WITH THE REST OF THE AREA
SEEING LIGHTER PRECIPITATION. BASED OFF THE THERMAL PROFILE...THAT
ALSO SEEMS TO BE THE LOCATION OF THE RAIN/SNOW/MIXED PRECIPITATION
LINE...LARGELY STRETCHING FROM KIMT/KSAW. THE CONCERN FOR THE
CENTRAL CWA WILL BE THE EXPECTED AREA OF SUBFREEZING TEMPERATURES
BELOW 875MB WHICH WOULD LEAD TO THE RAIN FREEZING WHEN IT GETS TO
THE SURFACE. OUT WEST...THE PRECIPITATION WILL LIKELY START OUT AS
FREEZING RAIN AS THE WARM NOSE ROTATES THROUGH AND THEN TRANSITION
TO SNOW FROM WEST TO EAST. WHEN COMBINED WITH THE NORTHERLY FLOW OFF
LAKE SUPERIOR WITH 850MB TEMPS FALLING TO -10C ON FRIDAY SHOULD SEE
LAKE ENHANCEMENT REALLY INCREASE AMOUNTS OVER GOGEBIC/ONTONAGON
COUNTIES THROUGH THE DAY ON FRIDAY. WITH THAT AREA SEEING BOTH THE
DEFORMATION PRECIPITATION AND THE LAKE ENHANCEMENT...CURRENT
EXPECTATION WOULD BE WARNING SNOWFALL AMOUNTS AND SOME LOCATIONS
COULD SEE SOME SIGNIFICANT SNOWFALL AMOUNTS FOR MID-LATE APRIL. IN
ADDITION TO THE SNOW...STRONG NORTHERLY WINDS FROM THE KEWEENAW
THROUGH GOGEBIC COUNTY WILL LEAD TO NEAR BLIZZARD CONDITIONS EVEN
THOUGH THE SNOW WILL LIKELY BE ON THE WETTER SIDE INITIALLY.
WILL CONTINUE THE SPS FOR THE WEDNESDAY NIGHT THROUGH FRIDAY
PERIOD...SINCE I FEEL THAT ENCOMPASSES THE ENTIRE SYSTEM WELL AND
SINCE THE THE MOST SIGNIFICANT EVENT WILL BE THE SECOND SYSTEM.
COULD HAVE DONE A LONG PERIOD WATCH TO COVER BOTH EVENTS...BUT SINCE
THE FIRST WAVE SEEMS TO BE MORE OF AN ADVISORY SITUATION AND THEN A
BRIEF BREAK ON THURSDAY AFTERNOON...WASN`T SURE IF THAT WOULD COME
ACROSS WELL WITH A LONG TERM WATCH HEADLINE.
EXPECT THE LAKE ENHANCED SNOW TO CONTINUE INTO FRIDAY NIGHT BUT
WILL QUICKLY COME TO AN END ON SATURDAY AS THE UPPER TROUGH LIFTS
TO THE NORTHEAST AND SURFACE HIGH PRESSURE BUILDS OVER THE AREA.
THIS SHOULD LEAD TO A NICE BUT COOL START TO THE WEEKEND...WITH
HIGHS ONLY REACHING THE 30S IN MOST LOCATIONS. THEN AS THE HIGH AND
UPPER RIDGE SHIFTS TO THE EAST ON SUNDAY...THE NEXT WAVE FROM THE
PACIFIC NORTHWEST WILL BE APPROACHING THE AREA FOR SUNDAY NIGHT AND
CONTINUING INTO MONDAY NIGHT AND TUESDAY. THERE CONTINUES TO BE
SOME DIFFERENCES IN THE DETERMINISTIC MODELS AND THERE ENSEMBLE
MEANS...BUT THE GENERAL IDEA OF THE UPPER TROUGH AND COLD FRONT
MOVING THROUGH THE AREA DURING THAT TIME SEEMS REASONABLE. THE AREA
WILL LIKELY SEE A BRIEF WARM UP FOR SUNDAY INTO MONDAY...BACK INTO
THE 40S...BUT THEN COOL TO BELOW NORMAL VALUES BEHIND THE COLD FRONT
ON TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 131 PM EDT TUE APR 16 2013
ABUNDANT 925-850 MB MOISTURE ALONG WITH DAYTIME HEATING SUPPORTED
BKN CIGS JUST ABOVE 3K FT AT IWD/SAW AND AROUND 2K FT AT CMX. EXPECT
MVFR CIGS WILL LIFT/SCATTER OUT TOWARD EVENING WITH CONTINUED MIXING
AND SLIGHTLY DRIER AIR MOVING IN. VFR CONDITIONS ARE EXPECTED
TONIGHT. ALTHOUGH THERE IS UNCERTAINTY WITH THE AMOUNT OF 925-900 MB
MOISTURE ACROSS NORTHERN UPPER MI WED MORNING...PER NAM/GFS...A
MENTION OF MVFR CIGS WAS INCLUDED.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 436 PM EDT TUE APR 16 2013
WINDS WILL STAY BELOW 30 KNOTS THROUGH THU BEFORE INCREASING OUT OF
THE NORTH THURSDAY NIGHT INTO FRIDAY NIGHT WHEN NORTH GALES ARE
LIKELY AS A DEEP LOW PRESSURE SYSTEM MOVES TOWARD NORTHERN LAKE
MICHIGAN AND EAST UPPER MICHIGAN. THERE IS THE POTENTIAL FOR HIGHER
END GALES WITH THIS SYSTEM IN THE 40 TO 45 KNOT RANGE. THE WINDS
WILL DIMINISH FRI NIGHT INTO SAT AS THE LOW MOVES QUICKLY TO THE
NORTHEAST OF THE REGION AND HIGH PRES BUILDS IN FROM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
219 PM EDT TUE APR 16 2013
.AVIATION...
//DISCUSSION...
THE FRONTAL BOUNDARY HAS SLIPPED SOUTHEAST OF THE AREA ACROSS FAR
EASTERN PORTIONS OF LAKE ERIE AND OHIO. BUILDING SURFACE HIGH
PRESSURE SOUTH OF HUDSON BAY REGION TONIGHT WILL ALLOW
ANTICYCLONIC FLOW TO BUILD SOUTHWARD INTO THE GREAT LAKES. THIS
SHOULD RESULT IN AN EVENING INLAND RELEASE OF THE LAKE/MARINE
AIRMASS...SUBSEQUENTLY DRYING OUT THE NEAR SURFACE ENVIRONMENT.
MEANWHILE...A SAMPLE OF THE HI RESOLUTION MODELS ARE SUGGESTING
SOME NORTHERN FRINGE SHOWERS AND MIDLEVEL MOISTURE WILL LIFT/CLIP
INTO THE SOUTHERN TAF SITES AFTER 21Z...PERSISTING INTO THE
EVENING. THIS IS A LOW CONFIDENCE FORECAST AS THOSE SOLUTIONS ARE
EXHIBITING SOME CONVECTIVE START UP ISSUES. WILL MONITOR AND AMEND
THE TAFS MORE PESSIMISTIC AS NEEDED.
//DTW THRESHOLD THREATS...
* LOW CONFIDENCE IN LIGHT PRECIPITATION POTENTIAL THIS EVENING.
* HIGH CONFIDENCE CEILINGS WILL FALL BELOW 5000FT AFTER 10Z
WEDNESDAY.
&&
.PREV DISCUSSION...ISSUED 613 AM EDT TUE APR 16 2013
UPDATE...
LOW LEVEL FGEN...NOT PICKED UP BY THE 00Z MODELS...WAS PICKED UP
BY THE 06Z MODELS AND CENTERED AROUND H9. DESPITE PICKING THIS LOW
LEVEL FGEN UP THE NWP MODELS CONTINUE TO UNDERESTIMATE THE CURRENT
ACTIVITY ABOUT TO SWEEP THROUGH EXTREME SOUTHEASTERN MICHIGAN.
HOWEVER THE RECENT 3KM HRRR MODEL PICKS THIS UP NICELY AND SWEEPS
THE MODERATE SHOWERS THROUGH THE AREA BETWEEN 10-13Z THIS MORNING.
WITH MODEST INSTABILITY AND INTERSPERSED LIGHTNING STRIKES WILL
ADD THUNDER TO THE MUCH RAISED POPS ACROSS THE SOUTHERN CWA THIS
MORNING AS THE COLD FRONT CONTINUES MARCHING SOUTHEASTWARD. AT
THIS TIME THE REST OF THE FORECAST LOOKS FINE GOING FORWARD AS THE
ACTIVITY TO THE NORTH HAS SIGNIFICANTLY DECREASED AS ADVERTISED.
PREV DISCUSSION...ISSUED 334 AM EDT TUE APR 16 2013
SHORT TERM...THIS MORNING THROUGH TONIGHT
AN AREA OF SHOWERS STRETCHING FROM CENTRAL LAKE HURON BACK TO
SOUTHERN LAKE MICHIGAN ALONG A SLOWLY MOVING COLD FRONT AND
COINCIDENT WITH FGEN IN THE H9-H7 LAYER WILL SLOWLY MOVE SOUTHEAST
DURING THE MORNING HOURS. HOWEVER MODEL CROSS SECTIONS SHOW THE FGEN
WILL ELONGATE...WEAKEN AND LIFT NORTH AS THE MORNING WEARS ON. DEEP
MOISTURE ASSOCIATED WITH THE FRONT WILL LIFT NORTH WITH THE MAIN
FGEN BAND...AS THE FRONT ITSELF BECOMES DIFFUSE TEMPERATURE-WISE.
THESE FACTORS DO NOT LEAD TO A HIGH DEGREE OF CONFIDENCE THAT RAIN
SHOWERS WILL ACTUALLY MAKE IT ALL THE WAY THROUGH THE SOUTHERN AND
EASTERN CWA THIS MORNING AS THE FRONT TRACKS TOWARDS THE NORTHERN
OHIO VALLEY. GIVEN THE WEAKENING DYNAMICS AND DECREASED AVAILABLE
MOISTURE WILL NOT DRAG THE CATEGORICAL POPS ALL THE THROUGH THE
SOUTHEASTERN CWA THIS MORNING AS THE FRONT MOVES SOUTH...AND INSTEAD
LEAVE LIKELY POPS ACROSS THESE AREAS PER THE PREVIOUS FORECAST. WITH
THE FRONT OVER THE NORTHERN OHIO VALLEY POPS WILL BE RATHER LOW THIS
AFTERNOON AND THIS EVENING AS THE MAIN DYNAMICS STAY TO THE SOUTH.
WITH A BETTER HANDLE ON THE PLACEMENT OF THE FRONT WILL TAKE THE
CHANCY POPS FROM THE AFTERNOON AND PLACE THEM IN THE EVENING HOURS
AS THE SURGE NORTHWARD OF THE MID-LEVEL FRONT AND INCREASED FGEN
OVER THE SOUTHERN GREAT LAKES DOES NOT MAKE IT INTO THE SOUTHEASTERN
MICHIGAN UNTIL LATER TONIGHT. THEREFORE WILL REFINE THE WINDOW FOR
LIKELY POPS TO AFTER MIDNIGHT WHEN THIS BETTER FORCING COMES BACK
INTO THE CWA. WITH MEAGER DYNAMICS AND NOT MUCH INSTABILITY TO SPEAK
OF WILL CONTINUE TO LEAVE THUNDER OUT OF THE FORECAST THROUGH
TONIGHT.
WITH THE PUSH OF COLD AIR BEHIND THE COLD FRONT BECOMING MORE
DIFFUSE...HIGH TEMPERATURES TODAY SHOULD BE ABLE TO GET INTO THE
UPPER 50S TO LOWER 60S. NORTHEAST WINDS OVERNIGHT WILL BRING COOLER
AIR IN FROM THE GREAT LAKES...WITH LOWS RANGING FROM THE MID 30S
ACROSS THE NORTH TO THE LOW TO MID 40S ACROSS THE SOUTH.
LONG TERM...
HIGHLY AMPLIFIED PATTERN DEVELOPING...AS UPPER LEVEL ENERGY OVER
PACIFIC NORTHWEST EXTENDING SOUTH INTO THE GREAT BASIN CONTINUES TO
CONSOLIDATE AND ORGANIZE. THE 00Z MODEL TRENDS ARE DEEPER WITH THE
SYSTEM COMING OUT OF THE CENTRAL CONUS/MIDWEST THURSDAY...AND IT NOW
APPEARS FRIDAY MORNING WILL BE MILD AND RAINY BEFORE THE STRONG LOW
LEVEL COLD ADVECTION SENDS 850 MB TEMPS BELOW ZERO BY 00Z SATURDAY.
THURSDAY/THURSDAY NIGHT LOOKS VERY WET ...AS IMPRESSIVE LOW LEVEL
JET (50 TO 55 KNOTS AT 850 MB) EXTENDS FROM TEXAS ALL THE WAY UP TO
THE CENTRAL GREAT LAKES...ALLOWING COPIOUS AMOUNTS OF GULF OF MEXICO
MOISTURE TO STREAM NORTHWARD. STILL HAVE SOME CONCERN FOR SEVERE
WEATHER ON THURSDAY WITH THE IMPRESSIVE WIND FIELDS...AS 00Z GFS
EVEN ADVERTISING SURFACE BASED CAPES IN SOLIDLY EXCESS OF 1000 J/KG
THERE IS A STRONG POSSIBILITY A FLOOD WATCH WILL BE NEEDED FOR
THURSDAY-FRIDAY MORNING TIME FRAME AS THIS DYNAMIC SYSTEM AND
MOISTURE LADEN (PW VALUES TO AROUND 1.5 INCHES) IMPACTS THE GREAT
LAKES REGION. THE FORECAST IS COMPLICATED ON THURSDAY DUE TO THE
FACT RIGHT ENTRANCE REGION FORCING OF THE UPPER LEVEL JET IS
DISPLACED WELL TO THE NORTH OF LOWER MICHIGAN...SO NOT A GUARANTEE
IS GOING TO RAIN ACROSS THE FAR SOUTHEAST AS WE REMAIN UNDER THE
INFLUENCE OF THE DEPARTING UPPER LEVEL RIDGE. ON THE FLIP SIDE...IF
THE ALL BLEND SURFACE DEW PTS OF 62-63 DEGREES VERIFY...THAT IS
CLIMATOLOGY NEAR RECORD TERRITORY...AND HARD TO BELIEVE THE ENHANCED
ISENTROPIC ASSENT WILL NOT GENERATE SHOWERS AND THUNDERSTORMS WITH
THE MORE THAN ADEQUATE INSTABILITY.
NEED TO MENTION THE POTENTIAL FOR STRONG WIND POP RIGHT BEHIND THE
POWERFUL COLD FRONT ON FRIDAY...AS 6 HR RISE/FALL PRESSURE COUPLET
IS INTENSIFYING THROUGH THE DAY...AND LOOKS TO BE AT LEAST 20 MB.
WITH THE STOUT LOW LEVEL COLD ADVECTION/SUBSIDENCE COMING THROUGH
DURING THE PEAK HEATING OF THE DAY...MIXING INTO THE 45 TO 50 KNOT
WINDS AT 850 MB DOES NOT LOOK TO BE MUCH OF A CHALLENGE...AND WILL
HIGHLIGHT THE POTENTIAL OF WIND GUSTS OF 45 MPH OR GREATER IN HWO.
QUIET BY COOL WEATHER FOR THE WEEKEND...AS 850 MB TEMPS STILL
PROGGED TO BE RUNNING AROUND -10 C TO START THE DAY ON
SATURDAY...BUT MODIFYING INTO THE MID SINGLE NUMBERS DURING THE
AFTERNOON...AND NEGATIVE LOW SINGLE NUMBERS FOR SUNDAY
AFTERNOON...PER 00Z EURO.
MARINE...
A SLOWLY MOVING COLD FRONT WILL FLIP THE WIND DIRECTION TO WNW
ACROSS ALL OF THE CENTRAL GREAT LAKES REGION THIS MORNING. WINDS
WILL THEN VEER TO THE NORTHEAST TONIGHT THEN TO AN EASTERLY
DIRECTION ON WEDNESDAY. HOWEVER SHORT DURATION FETCH AND A LACK OF
STRONGER WINDS WILL LIMIT SIGNIFICANT WAVE HEIGHTS TO 5 FEET OR LESS
ACROSS AREA WATERS THROUGH WEDNESDAY. PERSISTENT EASTERLY FLOW WILL
LEAD TO A BUILD UP OF WAVES ACROSS THE CENTRAL GREAT LAKES WEDNESDAY
NIGHT...WITH SMALL CRAFT HEADLINES A POSSIBILITY FOR ALL NEARSHORE
AREAS SAVE FOR INNER SAGINAW BAY. WILL ISSUE APPROPRIATE HEADLINES
AS NECESSARY AS THE EVENT DRAWS CLOSER.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....CB
UPDATE.......KURIMSKI
SHORT TERM...KURIMSKI
LONG TERM....SF
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
721 AM EDT TUE APR 16 2013
.AVIATION...
//DISCUSSION...
A COLD FRONT HAS CLEARED THE TAF SITES OVERNIGHT. AN AREA OF SHOWERS
FROM PTK SOUTH TO THE METRO AIRPORTS WILL SLOWLY CLEAR OUT OVER THE
NEXT FEW HOURS...LEAVING LOW LEVEL MOISTURE AND CLOUDS IN PLACE.
BEFORE THE SHOWERS EXIT EAST SOME THUNDERSTORMS ARE POSSIBLE AT THE
METRO AIRPORTS THROUGH 13Z AS LINGERING INSTABILITY CLEARS OUT OF
THE REGION. THE LOW CLOUDS WILL ERODE AS THE DAY WEARS ON AS LOW
LEVEL MOISTURE IS SCOURED OUT BY DRIER AIR ADVECTING IN WITH A RIDGE
OF HIGH PRESSURE. THIS PROCESS IS ALREADY UNDERWAY ACROSS NORTHERN
LOWER MICHIGAN AS CONDITIONS HAVE BECOME VFR. ALTHOUGH MODELS BRING
SHOWERS BACK OVER THE TAF SITES LATE TONIGHT...CONFIDENCE IN SHOWERS
IS NOT HIGH ENOUGH TO PUT INTO THE TAFS AT THIS POINT.
FOR DTW...THUNDERSTORMS SHOULD CLEAR THE AIRPORT AROUND 13Z WITH
LINGERING SHOWERS THROUGH 15Z AS THE COLD FRONT CONTINUES MARCHING
SOUTHEAST.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE THUNDERSTORMS WILL OCCUR EARLY THIS MORNING.
* HIGH CONFIDENCE CEILINGS WILL BE BELOW 5000 FT THIS MORNING.
&&
.PREV DISCUSSION...ISSUED 613 AM EDT TUE APR 16 2013
UPDATE...
LOW LEVEL FGEN...NOT PICKED UP BY THE 00Z MODELS...WAS PICKED UP
BY THE 06Z MODELS AND CENTERED AROUND H9. DESPITE PICKING THIS LOW
LEVEL FGEN UP THE NWP MODELS CONTINUE TO UNDERESTIMATE THE CURRENT
ACTIVITY ABOUT TO SWEEP THROUGH EXTREME SOUTHEASTERN MICHIGAN.
HOWEVER THE RECENT 3KM HRRR MODEL PICKS THIS UP NICELY AND SWEEPS
THE MODERATE SHOWERS THROUGH THE AREA BETWEEN 10-13Z THIS MORNING.
WITH MODEST INSTABILITY AND INTERSPERSED LIGHTNING STRIKES WILL
ADD THUNDER TO THE MUCH RAISED POPS ACROSS THE SOUTHERN CWA THIS
MORNING AS THE COLD FRONT CONTINUES MARCHING SOUTHEASTWARD. AT
THIS TIME THE REST OF THE FORECAST LOOKS FINE GOING FORWARD AS THE
ACTIVITY TO THE NORTH HAS SIGNIFICANTLY DECREASED AS ADVERTISED.
PREV DISCUSSION...ISSUED 334 AM EDT TUE APR 16 2013
SHORT TERM...THIS MORNING THROUGH TONIGHT
AN AREA OF SHOWERS STRETCHING FROM CENTRAL LAKE HURON BACK TO
SOUTHERN LAKE MICHIGAN ALONG A SLOWLY MOVING COLD FRONT AND
COINCIDENT WITH FGEN IN THE H9-H7 LAYER WILL SLOWLY MOVE SOUTHEAST
DURING THE MORNING HOURS. HOWEVER MODEL CROSS SECTIONS SHOW THE FGEN
WILL ELONGATE...WEAKEN AND LIFT NORTH AS THE MORNING WEARS ON. DEEP
MOISTURE ASSOCIATED WITH THE FRONT WILL LIFT NORTH WITH THE MAIN
FGEN BAND...AS THE FRONT ITSELF BECOMES DIFFUSE TEMPERATURE-WISE.
THESE FACTORS DO NOT LEAD TO A HIGH DEGREE OF CONFIDENCE THAT RAIN
SHOWERS WILL ACTUALLY MAKE IT ALL THE WAY THROUGH THE SOUTHERN AND
EASTERN CWA THIS MORNING AS THE FRONT TRACKS TOWARDS THE NORTHERN
OHIO VALLEY. GIVEN THE WEAKENING DYNAMICS AND DECREASED AVAILABLE
MOISTURE WILL NOT DRAG THE CATEGORICAL POPS ALL THE THROUGH THE
SOUTHEASTERN CWA THIS MORNING AS THE FRONT MOVES SOUTH...AND INSTEAD
LEAVE LIKELY POPS ACROSS THESE AREAS PER THE PREVIOUS FORECAST. WITH
THE FRONT OVER THE NORTHERN OHIO VALLEY POPS WILL BE RATHER LOW THIS
AFTERNOON AND THIS EVENING AS THE MAIN DYNAMICS STAY TO THE SOUTH.
WITH A BETTER HANDLE ON THE PLACEMENT OF THE FRONT WILL TAKE THE
CHANCY POPS FROM THE AFTERNOON AND PLACE THEM IN THE EVENING HOURS
AS THE SURGE NORTHWARD OF THE MID-LEVEL FRONT AND INCREASED FGEN
OVER THE SOUTHERN GREAT LAKES DOES NOT MAKE IT INTO THE SOUTHEASTERN
MICHIGAN UNTIL LATER TONIGHT. THEREFORE WILL REFINE THE WINDOW FOR
LIKELY POPS TO AFTER MIDNIGHT WHEN THIS BETTER FORCING COMES BACK
INTO THE CWA. WITH MEAGER DYNAMICS AND NOT MUCH INSTABILITY TO SPEAK
OF WILL CONTINUE TO LEAVE THUNDER OUT OF THE FORECAST THROUGH
TONIGHT.
WITH THE PUSH OF COLD AIR BEHIND THE COLD FRONT BECOMING MORE
DIFFUSE...HIGH TEMPERATURES TODAY SHOULD BE ABLE TO GET INTO THE
UPPER 50S TO LOWER 60S. NORTHEAST WINDS OVERNIGHT WILL BRING COOLER
AIR IN FROM THE GREAT LAKES...WITH LOWS RANGING FROM THE MID 30S
ACROSS THE NORTH TO THE LOW TO MID 40S ACROSS THE SOUTH.
LONG TERM...
HIGHLY AMPLIFIED PATTERN DEVELOPING...AS UPPER LEVEL ENERGY OVER
PACIFIC NORTHWEST EXTENDING SOUTH INTO THE GREAT BASIN CONTINUES TO
CONSOLIDATE AND ORGANIZE. THE 00Z MODEL TRENDS ARE DEEPER WITH THE
SYSTEM COMING OUT OF THE CENTRAL CONUS/MIDWEST THURSDAY...AND IT NOW
APPEARS FRIDAY MORNING WILL BE MILD AND RAINY BEFORE THE STRONG LOW
LEVEL COLD ADVECTION SENDS 850 MB TEMPS BELOW ZERO BY 00Z SATURDAY.
THURSDAY/THURSDAY NIGHT LOOKS VERY WET ...AS IMPRESSIVE LOW LEVEL
JET (50 TO 55 KNOTS AT 850 MB) EXTENDS FROM TEXAS ALL THE WAY UP TO
THE CENTRAL GREAT LAKES...ALLOWING COPIOUS AMOUNTS OF GULF OF MEXICO
MOISTURE TO STREAM NORTHWARD. STILL HAVE SOME CONCERN FOR SEVERE
WEATHER ON THURSDAY WITH THE IMPRESSIVE WIND FIELDS...AS 00Z GFS
EVEN ADVERTISING SURFACE BASED CAPES IN SOLIDLY EXCESS OF 1000 J/KG
THERE IS A STRONG POSSIBILITY A FLOOD WATCH WILL BE NEEDED FOR
THURSDAY-FRIDAY MORNING TIME FRAME AS THIS DYNAMIC SYSTEM AND
MOISTURE LADEN (PW VALUES TO AROUND 1.5 INCHES) IMPACTS THE GREAT
LAKES REGION. THE FORECAST IS COMPLICATED ON THURSDAY DUE TO THE
FACT RIGHT ENTRANCE REGION FORCING OF THE UPPER LEVEL JET IS
DISPLACED WELL TO THE NORTH OF LOWER MICHIGAN...SO NOT A GUARANTEE
IS GOING TO RAIN ACROSS THE FAR SOUTHEAST AS WE REMAIN UNDER THE
INFLUENCE OF THE DEPARTING UPPER LEVEL RIDGE. ON THE FLIP SIDE...IF
THE ALL BLEND SURFACE DEW PTS OF 62-63 DEGREES VERIFY...THAT IS
CLIMATOLOGY NEAR RECORD TERRITORY...AND HARD TO BELIEVE THE ENHANCED
ISENTROPIC ASSENT WILL NOT GENERATE SHOWERS AND THUNDERSTORMS WITH
THE MORE THAN ADEQUATE INSTABILITY.
NEED TO MENTION THE POTENTIAL FOR STRONG WIND POP RIGHT BEHIND THE
POWERFUL COLD FRONT ON FRIDAY...AS 6 HR RISE/FALL PRESSURE COUPLET
IS INTENSIFYING THROUGH THE DAY...AND LOOKS TO BE AT LEAST 20 MB.
WITH THE STOUT LOW LEVEL COLD ADVECTION/SUBSIDENCE COMING THROUGH
DURING THE PEAK HEATING OF THE DAY...MIXING INTO THE 45 TO 50 KNOT
WINDS AT 850 MB DOES NOT LOOK TO BE MUCH OF A CHALLENGE...AND WILL
HIGHLIGHT THE POTENTIAL OF WIND GUSTS OF 45 MPH OR GREATER IN HWO.
QUIET BY COOL WEATHER FOR THE WEEKEND...AS 850 MB TEMPS STILL
PROGGED TO BE RUNNING AROUND -10 C TO START THE DAY ON
SATURDAY...BUT MODIFYING INTO THE MID SINGLE NUMBERS DURING THE
AFTERNOON...AND NEGATIVE LOW SINGLE NUMBERS FOR SUNDAY
AFTERNOON...PER 00Z EURO.
MARINE...
A SLOWLY MOVING COLD FRONT WILL FLIP THE WIND DIRECTION TO WNW
ACROSS ALL OF THE CENTRAL GREAT LAKES REGION THIS MORNING. WINDS
WILL THEN VEER TO THE NORTHEAST TONIGHT THEN TO AN EASTERLY
DIRECTION ON WEDNESDAY. HOWEVER SHORT DURATION FETCH AND A LACK OF
STRONGER WINDS WILL LIMIT SIGNIFICANT WAVE HEIGHTS TO 5 FEET OR LESS
ACROSS AREA WATERS THROUGH WEDNESDAY. PERSISTENT EASTERLY FLOW WILL
LEAD TO A BUILD UP OF WAVES ACROSS THE CENTRAL GREAT LAKES WEDNESDAY
NIGHT...WITH SMALL CRAFT HEADLINES A POSSIBILITY FOR ALL NEARSHORE
AREAS SAVE FOR INNER SAGINAW BAY. WILL ISSUE APPROPRIATE HEADLINES
AS NECESSARY AS THE EVENT DRAWS CLOSER.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....KURIMSKI
UPDATE.......KURIMSKI
SHORT TERM...KURIMSKI
LONG TERM....SF
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
613 AM EDT TUE APR 16 2013
.UPDATE...
LOW LEVEL FGEN...NOT PICKED UP BY THE 00Z MODELS...WAS PICKED UP
BY THE 06Z MODELS AND CENTERED AROUND H9. DESPITE PICKING THIS LOW
LEVEL FGEN UP THE NWP MODELS CONTINUE TO UNDERESTIMATE THE CURRENT
ACTIVITY ABOUT TO SWEEP THROUGH EXTREME SOUTHEASTERN MICHIGAN.
HOWEVER THE RECENT 3KM HRRR MODEL PICKS THIS UP NICELY AND SWEEPS
THE MODERATE SHOWERS THROUGH THE AREA BETWEEN 10-13Z THIS MORNING.
WITH MODEST INSTABILITY AND INTERSPERSED LIGHTNING STRIKES WILL
ADD THUNDER TO THE MUCH RAISED POPS ACROSS THE SOUTHERN CWA THIS
MORNING AS THE COLD FRONT CONTINUES MARCHING SOUTHEASTWARD. AT
THIS TIME THE REST OF THE FORECAST LOOKS FINE GOING FORWARD AS THE
ACTIVITY TO THE NORTH HAS SIGNIFICANTLY DECREASED AS ADVERTISED.
&&
.PREV DISCUSSION...ISSUED 334 AM EDT TUE APR 16 2013
SHORT TERM...THIS MORNING THROUGH TONIGHT
AN AREA OF SHOWERS STRETCHING FROM CENTRAL LAKE HURON BACK TO
SOUTHERN LAKE MICHIGAN ALONG A SLOWLY MOVING COLD FRONT AND
COINCIDENT WITH FGEN IN THE H9-H7 LAYER WILL SLOWLY MOVE SOUTHEAST
DURING THE MORNING HOURS. HOWEVER MODEL CROSS SECTIONS SHOW THE FGEN
WILL ELONGATE...WEAKEN AND LIFT NORTH AS THE MORNING WEARS ON. DEEP
MOISTURE ASSOCIATED WITH THE FRONT WILL LIFT NORTH WITH THE MAIN
FGEN BAND...AS THE FRONT ITSELF BECOMES DIFFUSE TEMPERATURE-WISE.
THESE FACTORS DO NOT LEAD TO A HIGH DEGREE OF CONFIDENCE THAT RAIN
SHOWERS WILL ACTUALLY MAKE IT ALL THE WAY THROUGH THE SOUTHERN AND
EASTERN CWA THIS MORNING AS THE FRONT TRACKS TOWARDS THE NORTHERN
OHIO VALLEY. GIVEN THE WEAKENING DYNAMICS AND DECREASED AVAILABLE
MOISTURE WILL NOT DRAG THE CATEGORICAL POPS ALL THE THROUGH THE
SOUTHEASTERN CWA THIS MORNING AS THE FRONT MOVES SOUTH...AND INSTEAD
LEAVE LIKELY POPS ACROSS THESE AREAS PER THE PREVIOUS FORECAST. WITH
THE FRONT OVER THE NORTHERN OHIO VALLEY POPS WILL BE RATHER LOW THIS
AFTERNOON AND THIS EVENING AS THE MAIN DYNAMICS STAY TO THE SOUTH.
WITH A BETTER HANDLE ON THE PLACEMENT OF THE FRONT WILL TAKE THE
CHANCY POPS FROM THE AFTERNOON AND PLACE THEM IN THE EVENING HOURS
AS THE SURGE NORTHWARD OF THE MID-LEVEL FRONT AND INCREASED FGEN
OVER THE SOUTHERN GREAT LAKES DOES NOT MAKE IT INTO THE SOUTHEASTERN
MICHIGAN UNTIL LATER TONIGHT. THEREFORE WILL REFINE THE WINDOW FOR
LIKELY POPS TO AFTER MIDNIGHT WHEN THIS BETTER FORCING COMES BACK
INTO THE CWA. WITH MEAGER DYNAMICS AND NOT MUCH INSTABILITY TO SPEAK
OF WILL CONTINUE TO LEAVE THUNDER OUT OF THE FORECAST THROUGH
TONIGHT.
WITH THE PUSH OF COLD AIR BEHIND THE COLD FRONT BECOMING MORE
DIFFUSE...HIGH TEMPERATURES TODAY SHOULD BE ABLE TO GET INTO THE
UPPER 50S TO LOWER 60S. NORTHEAST WINDS OVERNIGHT WILL BRING COOLER
AIR IN FROM THE GREAT LAKES...WITH LOWS RANGING FROM THE MID 30S
ACROSS THE NORTH TO THE LOW TO MID 40S ACROSS THE SOUTH.
LONG TERM...
HIGHLY AMPLIFIED PATTERN DEVELOPING...AS UPPER LEVEL ENERGY OVER
PACIFIC NORTHWEST EXTENDING SOUTH INTO THE GREAT BASIN CONTINUES TO
CONSOLIDATE AND ORGANIZE. THE 00Z MODEL TRENDS ARE DEEPER WITH THE
SYSTEM COMING OUT OF THE CENTRAL CONUS/MIDWEST THURSDAY...AND IT NOW
APPEARS FRIDAY MORNING WILL BE MILD AND RAINY BEFORE THE STRONG LOW
LEVEL COLD ADVECTION SENDS 850 MB TEMPS BELOW ZERO BY 00Z SATURDAY.
THURSDAY/THURSDAY NIGHT LOOKS VERY WET ...AS IMPRESSIVE LOW LEVEL
JET (50 TO 55 KNOTS AT 850 MB) EXTENDS FROM TEXAS ALL THE WAY UP TO
THE CENTRAL GREAT LAKES...ALLOWING COPIOUS AMOUNTS OF GULF OF MEXICO
MOISTURE TO STREAM NORTHWARD. STILL HAVE SOME CONCERN FOR SEVERE
WEATHER ON THURSDAY WITH THE IMPRESSIVE WIND FIELDS...AS 00Z GFS
EVEN ADVERTISING SURFACE BASED CAPES IN SOLIDLY EXCESS OF 1000 J/KG
THERE IS A STRONG POSSIBILITY A FLOOD WATCH WILL BE NEEDED FOR
THURSDAY-FRIDAY MORNING TIME FRAME AS THIS DYNAMIC SYSTEM AND
MOISTURE LADEN (PW VALUES TO AROUND 1.5 INCHES) IMPACTS THE GREAT
LAKES REGION. THE FORECAST IS COMPLICATED ON THURSDAY DUE TO THE
FACT RIGHT ENTRANCE REGION FORCING OF THE UPPER LEVEL JET IS
DISPLACED WELL TO THE NORTH OF LOWER MICHIGAN...SO NOT A GUARANTEE
IS GOING TO RAIN ACROSS THE FAR SOUTHEAST AS WE REMAIN UNDER THE
INFLUENCE OF THE DEPARTING UPPER LEVEL RIDGE. ON THE FLIP SIDE...IF
THE ALL BLEND SURFACE DEW PTS OF 62-63 DEGREES VERIFY...THAT IS
CLIMATOLOGY NEAR RECORD TERRITORY...AND HARD TO BELIEVE THE ENHANCED
ISENTROPIC ASSENT WILL NOT GENERATE SHOWERS AND THUNDERSTORMS WITH
THE MORE THAN ADEQUATE INSTABILITY.
NEED TO MENTION THE POTENTIAL FOR STRONG WIND POP RIGHT BEHIND THE
POWERFUL COLD FRONT ON FRIDAY...AS 6 HR RISE/FALL PRESSURE COUPLET
IS INTENSIFYING THROUGH THE DAY...AND LOOKS TO BE AT LEAST 20 MB.
WITH THE STOUT LOW LEVEL COLD ADVECTION/SUBSIDENCE COMING THROUGH
DURING THE PEAK HEATING OF THE DAY...MIXING INTO THE 45 TO 50 KNOT
WINDS AT 850 MB DOES NOT LOOK TO BE MUCH OF A CHALLENGE...AND WILL
HIGHLIGHT THE POTENTIAL OF WIND GUSTS OF 45 MPH OR GREATER IN HWO.
QUIET BY COOL WEATHER FOR THE WEEKEND...AS 850 MB TEMPS STILL
PROGGED TO BE RUNNING AROUND -10 C TO START THE DAY ON
SATURDAY...BUT MODIFYING INTO THE MID SINGLE NUMBERS DURING THE
AFTERNOON...AND NEGATIVE LOW SINGLE NUMBERS FOR SUNDAY
AFTERNOON...PER 00Z EURO.
MARINE...
A SLOWLY MOVING COLD FRONT WILL FLIP THE WIND DIRECTION TO WNW
ACROSS ALL OF THE CENTRAL GREAT LAKES REGION THIS MORNING. WINDS
WILL THEN VEER TO THE NORTHEAST TONIGHT THEN TO AN EASTERLY
DIRECTION ON WEDNESDAY. HOWEVER SHORT DURATION FETCH AND A LACK OF
STRONGER WINDS WILL LIMIT SIGNIFICANT WAVE HEIGHTS TO 5 FEET OR LESS
ACROSS AREA WATERS THROUGH WEDNESDAY. PERSISTENT EASTERLY FLOW WILL
LEAD TO A BUILD UP OF WAVES ACROSS THE CENTRAL GREAT LAKES WEDNESDAY
NIGHT...WITH SMALL CRAFT HEADLINES A POSSIBILITY FOR ALL NEARSHORE
AREAS SAVE FOR INNER SAGINAW BAY. WILL ISSUE APPROPRIATE HEADLINES
AS NECESSARY AS THE EVENT DRAWS CLOSER.
&&
.AVIATION...ISSUED 1149 PM EDT MON APR 15 2013
//DISCUSSION...
A COLD FRONT NOW OVER MBS WILL SLOWLY ADVANCE ACROSS SE MI EARLY
THIS MORNING...PASSING THROUGH METRO DETROIT AROUND 09Z. A REGION OF
SHOWERS WILL OCCUR ALONG AND IN THE WAKE OF THIS COLD FRONT. THE
ADDED LOW LEVEL MOISTURE WILL RAPIDLY LOWER CEILINGS TO MVFR WITH
SOME IFR CONDITIONS POSSIBLE IN THE IMMEDIATE POST FRONTAL AIRMASS.
THE FRONTAL PASSAGE WILL ALSO BE MARKED BY AN ABRUPT SHIFT IN THE
WINDS TO THE W-NW. CONDITIONS ARE EXPECTED TO IMPROVE MARKEDLY LATE
TUES MORNING AS DRY AIR FUNNELS IN FROM THE WEST.
FOR DTW...MORE SIGNIFICANT LOWERING OF CEILINGS AND SHOWERS WILL
HOLD OFF UNTIL 09 TO 11Z GIVEN THE LATE ARRIVAL OF THE COLD FRONT.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE CEILINGS WILL BE BELOW 5000 FT TUESDAY MORNING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......KURIMSKI
AVIATION.....SC
SHORT TERM...KURIMSKI
LONG TERM....SF
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
116 AM EDT TUE APR 16 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 420 PM EDT MON APR 15 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR TROF
STRETCHING FM MN THRU THE PAC NW UPSTREAM OF UPR RDG OVER THE ERN
CONUS. SHRTWV THAT CAUSED WINTRY MIX OF PCPN SUN INTO THIS MRNG IS
LIFTING NEWD THRU MN ON THE ERN FLANK OF THE UPR TROF AXIS. DRY SLOT
ON THE ERN FLANK OF THIS DISTURBANCE HAS ADVECTED MUCH DRIER MID LVL
AIR OVER UPR MI WITH SW H7 WINDS UP TO 73 KTS AS SHOWN ON THE 12Z
GRB RAOB. SINCE WARM CONVEYOR BELT MSTR HAS ALSO SHIFTED TO THE E...
THE CWA IS PCPN FREE THIS AFTN. RETURN OF SUNSHINE UNDER THE DRY
SLOTTING OVER THE W AND CENTRAL HAS CAUSED TEMPS TO RECOVER TO MORE
SEASONABLE LVLS. OVER THE E...LO CLDS HAVE BEEN MORE PERSISTENT WITH
SSW LLVL FLOW OFF THE CHILLY LK MI WATERS AND LLVL MSTR SHOWN ON THE
12Z GRB RAOB. BKN SC HAS ALSO DVLPD OVER THE W AS DAYTIME HEATING
HAS DESTABILIZED LLVL LAPSE RATES WITH INFLUX OF LOWER H85 TEMPS AND
ARRIVAL OF MOISTER LLVL AIR DEPICTED ON THE 12Z MPX RAOB.
TNGT...SHRTWV/SFC LO IN MN ARE PROGGED TO SHIFT NEWD THRU NW
ONTARIO. ALTHOUGH SUPPORTING DEEP LYR QVECTOR CNVGC/DEEPER MSTR WL
SLIDE TO THE NW OF UPR MI...THERE MAY BE ENUF MOISTENING OVER THE W
WITH THE SLOW ARRIVAL OF COLDER AIR TO JUSTIFY RETAINING FCST OF
SCHC POPS IN THAT AREA...ESPECIALLY OVERNGT WITH A WSHFT TO AN
UPSLOPE W COMPONENT COINCIDENT WITH LO PRES TROF PASSAGE TO THE S OF
LO MOVING THRU NW ONTARIO. ALTHOUGH THERE MAY BE MORE SC OVER THE CNTRL AS
WELL...THE TRANSITION TO A MORE W WIND SHOULD AID CLRG OVER THE E.
TUE...LO PRES TROF ON THE SW FLANK OF DEPARTING SHRTWV/SFC LO TOWARD
JAMES BAY WL CROSS UPR MI BY EARLY AFTN. ALTHOUGH THERE WL LIKELY BE
QUITE A BIT OF SC IN THE MOIST CYC W-SW SHIFTING NW FLOW...SHARP INVRN
NEAR H8 SHOWN ON FCST SDNGS IN THE ABSENCE OF ANY UPR SUPPORT WL
SQUASH POPS AWAY FM THE W...WHERE UPSLOPE FLOW MIGHT GENERATE A FEW
-SHSN IN THE MRNG. AS THE LLVL FLOW TRENDS MORE ACYC DURING THE AFTN
FOLLOWING THE TROF PASSAGE AND SE OF HI PRES BLDG TOWARD NW
ONTARIO...THE SC MAY TEND TO BREAK UP IN THE AFTN...ESPECIALLY
DOWNWIND OF LK SUP WITH SPRING STABILIZATION IN THE AFTN OFF THE
WATER. DEEP MIXING TO H8-85 WL SUPPORT MAX TEMPS APRCHG 50 OVER THE
SCENTRAL WITH DOWNSLOPE NW FLOW. AREAS NEAR LK SUP WL BE COOLER.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 451 PM EDT MON APR 15 2013
THERE ARE A COUPLE OF PERIODS OF CONCERN IN THIS LONG TERM PERIOD.
THE FIRST WILL PUSH IN FROM THE SOUTHWEST WEDNESDAY EVENING THROUGH
THURSDAY MORNING...WITH A SECONDARY SURGE OF MOISTURE SLIDING ACROSS
UPPER MICHIGAN THURSDAY NIGHT INTO FRIDAY. LATE THIS WEEKEND INTO
EARLY NEXT WEEK MAY ALSO END UP BEING INTERESTING...WITH ANOTHER
SURGE OF WARM AIR PUSHES IN FROM THE SOUTH.
AT 00Z WEDNESDAY A WEAK SFC TROUGH MAY STILL BE OVER CENTRAL LAKE
SUPERIOR AND NORTHERN UPPER MICHIGAN...BUT THAT FEATURE SHOULD EXIT
QUICKLY AS THE LARGE AREA OF HIGH PRESSURE OVER CENTRAL CANADA
PUSHES INTO ONTARIO AND LAKE SUPERIOR OVERNIGHT. KEPT CONDITIONS DRY
FOR NOW...ALTHOUGH SOME OF THE SMALLER SCALE MODELS DID INDICATE A
FEW LIGHT FLURRIES OR SNOW SHOWERS. OTHERWISE...DRY CONDITIONS
SHOULD LINGER THROUGH WEDNESDAY MORNING...AS THE HIGH PRESSURE
SYSTEM SLOWLY EXITS TO EASTERN ONTARIO AND OVER JAMES BAY BY 00Z
THURSDAY.
WILL CONTINUE TO HEDGE THE FORECAST CLOSER TO THE ECMWF WITH THIS
PACKAGE UPDATE. ALTHOUGH IT IS A LITTLE WEAKER AND EASTWARD WITH
THE SURFACE LOW TO OUR SOUTH AND EAST DURING THE DAY THURSDAY...BOTH
THE GFS AND ECMWF HAVE THE SURFACE LOW OVER FAR EASTERN UPPER
MICHIGAN AT 18Z FRIDAY /ALTHOUGH THE GFS IS DEEPER WITH THE SYSTEM/.
PRECIPITATION TYPE AND AMOUNTS REMAIN A CONCERN...WITH RAIN MAINLY
CENTRAL AND EAST...CLOSER TO THE LOW. WEDNESDAY NIGHT STILL LOOKS
LIKE A POTENTIAL FOR FREEZING RAIN...WITH SURFACE TEMPERATURES OF
29-32F BETWEEN 01-11Z THURSDAY. WHILE THE TYPICAL ROADWAYS MAY STAY
WARM ENOUGH FOR WET CONDITIONS DUE TO LINGER SALT DEPOSITS ALREADY
ON THEM...AND BEING MORE WELL-TRAVELED. AS WE MOVE DEEPER INTO THE
SPRING SEASON IT BECOME INCREASINGLY DIFFICULT FOR ROADWAYS TO STAY
BELOW FREEZING FOR TOO LONG. STILL HAVE A GOOD CHANCE OF FREEZING
RAIN ACCUMULATING TO GENERALLY LESS THAN A TENTH OF AN INCH. KEPT
THE MENTION IN THE HWO AT THIS POINT. ALSO HAVE THE POTENTIAL FOR
2-4 INCHES OF HEAVY WET SNOW OVER THE HIGHER TERRAIN OF THE WEST
WEDNESDAY NIGHT...LINGERING INTO THURSDAY WITH A SMALL BREAK FIGURED
BEFORE WE COME UNDER THE INFLUENCE OF THE 500MB TROUGH AND COLDER
AIR PUSHING IN FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT.
NNE 850MB WINDS OF 30-50KT LOOK REALISTIC FROM 06-15Z
FRIDAY...BEFORE TURNING MORE NORTHERLY AS THE LOW PUSHES ACROSS
EASTERN UPPER MICHIGAN. INTRODUCED GALE FORCE VALUES TO PORTIONS OF
MAINLY CENTRAL LAKE SUPERIOR FRIDAY INTO FRIDAY EVENING...BUT WOULD
NOT BE SURPRISED IF WE NEED TO BUMP UP OUR FORECAST FOR THE NE WINDS
FUNNELING DOWN THE WESTERN HALF OF LAKE SUPERIOR EARLIER IN THE DAY.
THE WEST END OF THE CWA /GOGEBIC AND ONTONAGON COUNTIES/ WILL ALSO
HAVE THE BEST CHANCE OF LAKE EFFECT/LAKE ENHANCED SNOW
ACCUMULATIONS...WITH 850MB TEMPS GENERALLY COOLING BELOW -6C.
LIGHTER AMOUNTS ARE FIGURED EAST...WITH WARMER AIR WILL AROUND AND A
MIX OF RAIN OR SNOW POSSIBLE FAR EAST THROUGH THE DAY FRIDAY.
DRY WEATHER SHOULD BE THE RULE ONCE AGAIN STARTING SATURDAY AS HIGH
PRESSURE BUILDS IN AT THE SFC. HOWEVER WITH NW FLOW LINGERING ALOFT
AND N-NNW WINDS AT THE SURFACE...ALONG WITH 850MB TEMPS OF -11 TO
-14C...LINGERING SNOW SHOWERS WILL BE POSSIBLE EAST OF MARQUETTE
NEAR LAKE SUPERIOR INTO THE MID/LATE MORNING HOURS.
THERE ARE SIGNIFICANT TIMING DIFFERENCES WITH THE APPROACH OF THE
NEXT SYSTEM. THEY DO AGREE ON STRONG S WINDS AT 850MB...AGAIN
APPROACHING THE 40-55KT RANGE FROM MAINLY LATE SUNDAY AFTERNOON
THROUGH MONDAY MORNING...AS THE LLJ PUSHES W TO E ACROSS THE CWA.
THE MAIN ISSUE IS REGARDING THE TIMING OF THE NEXT SURGE OF
MOISTURE/PRECIPITATION...WHICH THE 15/12Z GFS IS MUCH MORE
PROGRESSIVE AND BRINGS IN MORNING TO THE WEST HALF. THIS IS APPROX 6
OR MORE HOURS FASTER THAN THE 15/06Z GFS RUN. THE 12Z ECMWF SHOWED A
SLOWER SOLUTION. GIVEN THE VARIABILITY SHOWN IN THE AVAILABLE
MODELS...IT SEEMS REASONABLE TO CONCENTRATE A BIT MORE ON THE NEAR
TERM...AND RUN WITH A CONTINUED CONSENSUS APPROACH AFTER 00Z MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 115 AM EDT TUE APR 16 2013
LOW-LEVEL MOISTURE WRAPPING AROUND MIDLEVEL LOW PASSING JUST N OF
LAKE SUPERIOR WILL LIKELY RESULT IN MVFR CIGS AT KIWD/KCMX THRU THE
MORNING HRS. APPROACH AND PASSAGE OF SFC TROF LATE IN THE NIGHT
SHOULD BRING LOW MVFR CIGS (PERHAPS IFR) TO KCMX ALONG WITH THE
POSSIBILITY OF -SHSN/FLURRIES. AT KSAW...VFR CONDITIONS WILL PREVAIL
FOR THE NEXT SEVERAL HRS...BUT PASSAGE OF SFC TROF AROUND DAYBREAK
SHOULD BRING HIGH MVFR CIGS. MVFR CIGS WILL LIFT/SCATTER OUT
MID/LATE AFTN AT KIWD/KCMX. EXPECT CIGS TO RISE TO VFR BY LATE
MORNING AT KSAW. VFR CONDITIONS WILL THEN BE THE RULE THRU THE
EVENING HRS AT ALL 3 SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 451 PM EDT MON APR 15 2013
SHORT LIVED GALE EVENT WILL CONTINUE TO WIND DOWN EARLY THIS MORNING
ACROSS THE EAST HALF OF LAKE SUPERIOR AS THE LOW NEARS THE AREA AND
ALSO WEAKENS WHICH WILL WEAKEN THE PRESSURE GRADIENT. WINDS THEN
DECREASE TUESDAY INTO WEDNESDAY BEFORE INCREASING OUT OF THE N
THURSDAY INTO FRIDAY WHEN GALES MAY BE POSSIBLE AGAIN AS ANOTHER
STRONG LATE SPRING SNOWSTORM AFFECTS THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
536 PM MDT WED APR 17 2013
.AVIATION...
00Z TAF CYCLE
LOW CLOUDS WILL SURGE SOUTH AGAIN TONIGHT AS A POTENT BACK DOOR
COLD FRONT SURGES INTO THE EASTERN PLAINS. LATEST RUC AND NAM
SOLUTIONS INDICATE LOW CLOUDS NEAR 015 WILL MAKE IT BACK INTO
KTCC AND SATELLITE CONFIRMS...SO HAVE ADDED BKN CIGS THERE FOR
SEVERAL HOURS TONIGHT. SOME LIGHT PRECIP MAY DEVELOP BEHIND THE
FRONT AS WELL HOWEVER LEFT OUT SINCE CONFIDENCE NOT AS HIGH.
MODELS BOTH AGREE AS WELL WITH FRONT PUSHING INTO KROW WITH A
SCT TO BKN DECK BUT NOT NEARLY AS CONFIDENCE THERE SO LEFT SCT
DECK FOR NOW. ELSEWHERE...WINDS AND BLDU WILL TAPER OFF THIS
EVENING. PRECIP WILL BECOME TERRAIN DOMINATED OVER THE NORTH
WHERE A COUPLE INCHES OF SNOW AND IFR CIGS WILL OCCUR. THE MAIN
IMPACT AREA FOR SNOW WILL BE THE NE PLAINS FROM RATON EAST TO
CLAYTON. SKIES WILL CLEAR THURSDAY FROM WEST TO EAST...EXCEPT
FOR THE NE CORNER WHERE MODELS CONTINUE TO INDICATE SOME LIGHT
PRECIP PUSHING EAST OFF THE HIGH TERRAIN. GUYER
&&
.PREV DISCUSSION...330 PM MDT WED APR 17 2013...
PLETHORA OF HIGHLIGHTS OUT SO WILL KEEP THIS SHORT. UPPER LEVEL
LOW/TROUGH NEAR THE FOUR CORNERS EARLY THIS AFTERNOON. RELATIVELY
MOIST SOUTHWEST FLOW ALOFT CONTINUING TO BRING OCCASIONAL LIGHT
TO MODERATE SNOW TO PORTIONS OF THE NORTHERN MOUNTAINS. LIGHT
ACCUMULATION REPORTED IN CHAMA AND DULCE BY LATE THIS MORNING WITH
LIGHT SNOW AND A TRACE OF ACCUMULATION AT ANGEL FIRE. BACKDOOR FRONT
REMAINED NEARLY STATIONARY TODAY...FROM NEAR A TRINIDAD TO RATON
TO TUCUMCARI LINE. APPROXIMATELY A 40F DIFFERENCE BETWEEN THE
AIRMASS TO THE NORTH OF THE FRONT OVER NE NM AND THE AIRMASS OVER
SE NM. UPPER LOW/TROUGH WILL CONTINUE TO SLOWLY TRANSLATE EWD THIS
EVENING...WITH THE TROUGH AXIS LOCATED ALONG INTERSTATE 25 OR SO BY
AROUND MIDNIGHT. NAM AND GFS IN GOOD AGREEMENT THAT AS THE 700MB
WAVE CROSSES THE ROCKIES EARLY THIS EVENING...THE MID LEVEL FLOW
TURNS NORTHERLY AND THE COLD AIR OVER ERN COLORADO/BACKDOOR FRONT
SURGES SOUTHWARD OVERNIGHT. DECIDED TO INCLUDE THE FAR NE
HIGHLANDS...UNION AND HARDING COUNTIES IN THE WINTER WEATHER
ADVISORY OVERNIGHT. 12Z NAM12 HITTING THIS AREA QUITE HARD WITH
SNOW THIS EVENING AND WITH VISIBLE SATELLITE IMAGERY SHOWING SIGNS
OF STRONG FRONTOGENETIC FORCING ALONG WITH MID-LEVEL INSTABILITY OVER NE
NM/SE CO STARTING TO TAKE SHAPE.
UPPER LEVEL TROUGH SLOW TO SHIFT EWD THURSDAY WITH ONE LAST SPEED
MAX TO ROUND THE BASE OF THE TROUGH. SURFACE CONVERGENCE ALONG
WITH COLD AIR ALOFT WILL LEAD TO SCATTERED SNOW SHOWERS FOR THE
NORTHERN MOUNTAINS DURING THE AFTERNOON.
DRY NW FLOW ALOFT TRANSITIONS OVERHEAD THURSDAY NIGHT AND FRIDAY.
WARMING TREND GETS UNDERWAY AREA-WIDE FRIDAY WITH TEMPERATURES
STARTING TO AT LEAST APPROACH AVERAGE LEVELS. THE WARMING TREND
CONTINUES INTO THE WEEKEND...ALBEIT A WEAK SHORT-WAVE CLIPS THE
FAR NORTH/NE PART OF THE STATE SLOWING THE WARMING TREND THERE
WITH A SLIGHT CHANCE FOR A LIGHT MOUNTAIN SHOWER. MEDIUM RANGE
GLOBAL MODELS SEEM TO BE SETTLING ON TIMING AND PLACEMENT OF THE
NEXT COLD UPPER LEVEL TROUGH AND UNSEASONABLY STRONG BACK DOOR
COLD FRONT FOR EARLY NEXT WEEK. 33
.FIRE WEATHER...
STRONG SURFACE WINDS AND RELATIVE HUMIDITY BELOW 15 PERCENT WILL
CONTINUE TO PRODUCE RED FLAG CONDITIONS THROUGH MID EVENING ACROSS
ZONES 106...107 AND 108. STRONGEST WINDS WILL DIMINISH AFTER THAT
TIME AND LESSEN THE FIRE WEATHER CONDITIONS. BASE OF UPPER LEVEL LOW
WILL MOVE ACROSS NORTHERN NM TONIGHT...WHILE A COLD FRONT PUSHES
SOUTHWARD ACROSS EASTERN NM. THESE TWO SYSTEMS WILL PRODUCE LIGHT TO
OCCASIONALLY MODERATE SNOWFALL ACROSS THE NORTHERN SANGRE DE
CRISTOS...THE NORTHERN HIGHLANDS AND THE FAR NORTHEASTERN PLAINS.
WETTING PRECIPITATION IS LIKELY ACROSS THESE AREAS TONIGHT.
INCREASING LOW LEVEL MOISTURE TONIGHT WILL PRODUCE VERY GOOD TO
EXCELLENT RECOVERIES ACROSS THE NORTHERN MOUNTAINS AND EASTERN
PLAINS. FAIR TO GOOD OVERNIGHT RECOVERIES ARE EXPECTED ACROSS THE
REMAINDER OF THE REGION. WINDS WILL DROP BELOW 15 MPH ACROSS MOST OF
THE REGION AFTER MIDNIGHT...EXCEPT BEHIND THE COLD FRONT IN THE
EASTERN PLAINS. A WIND ADVISORY WILL REMAIN IN EFFECT ACROSS THE
EASTERN PLAINS THROUGH DAWN THURSDAY WITH NORTH TO NORTHEAST WINDS
GREATER THAN 30 MPH.
AS THE UPPER LOW MOVES AWAY FROM NM INTO THE U.S. CENTRAL PLAINS
THURSDAY...A DEEP NORTHWEST FLOW WILL SET UP ACROSS THE STATE.
NORTHWEST WIND WEST OF THE DIVIDE WILL GUST TO 30 MPH IN THE
AFTERNOON...BUT RELATIVE HUMIDITY WILL REMAIN ABOVE CRITICAL VALUES.
RELATIVE HUMIDITY ACROSS THE SOUTHERN ZONES WILL DIP BRIEFLY BELOW
15 PERCENT...BUT WIND SPEEDS AND GUSTS ACROSS THIS AREA WILL BE
LIGHTER. VENTILATION THURSDAY WILL BE VERY GOOD WEST OF THE DIVIDE
AND GOOD EAST OF THE DIVIDE.
SURFACE HIGH PRESSURE TO THE NORTH WILL BEGIN TO BUILD SOUTHWARD
ACROSS NM THURSDAY NIGHT...AND LIGHT NORTH TO NORTHWEST WINDS ARE
EXPECTED. EXPECT INVERSIONS TO DEVELOP IN THE VALLEY AND LOW-LYING
AREAS LATE THURSDAY NIGHT. RECOVERIES WILL BE FAIR TO GOOD IN MOST
LOCATIONS AND WILL BE VERY GOOD TO EXCELLENT ACROSS NORTHERN NM.
WEAK HIGH PRESSURE ALOFT AND MODERATE SURFACE HIGH PRESSURE WILL
BUILD ACROSS NM FRIDAY. THIS WEATHER PATTERN WILL PRODUCE LIGHT
WINDS FOR THE ENTIRE REGION WITH GUSTS GENERALLY LESS THAN 20 MPH IN
THE AFTERNOON. MORNING INVERSIONS WILL BE SLOW TO BURN OFF
FRIDAY...ESPECIALLY WEST OF THE DIVIDE. SIGNIFICANTLY DRIER AIR WILL
MOVE ACROSS NM FROM THE WEST FRIDAY. THIS AIR MASS WILL CAUSE
AFTERNOON RELATIVE HUMIDITY TO FALL BELOW 15 PERCENT IN MOST
LOCATIONS...EXCEPT IN THE NORTHERN MOUNTAINS. VENTILATION WILL BE
POOR TO FAIR DURING THE MORNING HOURS...AND THEN IMPROVE TO GOOD TO
VERY GOOD IN THE AFTERNOON.
DRY AIR MASS WILL REMAIN IN PLACE ACROSS NM FRIDAY NIGHT. OVERNIGHT
RELATIVE HUMIDITY RECOVERIES WILL BE POOR TO FAIR...EXCEPT IN THE
NORTHERN MOUNTAINS...WHERE RECOVERIES ARE EXPECTED TO BE GOOD. WINDS
WILL BE LIGHT WEST OF THE DIVIDE FRIDAY NIGHT. SURFACE LOW PRESSURE
FORMING IN EASTERN CO FRIDAY NIGHT WILL GENERATE LIGHT TO MODERATE
SOUTH TO SOUTHEAST WINDS IN THE EASTERN PLAINS. RECOVERIES WILL BE
POOR ACROSS SOUTH CENTRAL ZONES AND FAIR ELSEWHERE.
A COMBINATION OF DEVELOPING SURFACE LOW PRESSURE ACROSS WESTERN TX
AND STRENGTHENING WINDS ALOFT SATURDAY WILL AN INCREASE IN WIND
SPEEDS EAST OF THE DIVIDE. AFTERNOON WINDS EAST OF THE DIVIDE WILL
GUST UP TO 35 MPH IN THE AFTERNOON HOURS. LOW RELATIVE HUMIDITY AND
GUSTY WINDS HAVE THE POTENTIAL TO CREATE 3 TO 5 HOURS OF NEAR
CRITICAL FIRE WEATHER CONDITIONS ALONG I-40 FROM CLINES CORNERS TO
SANTA ROSA SATURDAY AFTERNOON. VENTILATION WILL BE FAIR TO GOOD IN
THE MORNING HOURS AND RAPIDLY IMPROVE IN THE EARLY AFTERNOON TO
BECOME EXCELLENT ACROSS ALL OF NM.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM MDT THURSDAY FOR THE FOLLOWING
ZONES...NMZ515-527-528-530-531.
WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR THE FOLLOWING ZONES...
NMZ521>524-528-529-531>533-536>538.
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR THE FOLLOWING
ZONES...NMZ106>108.
HARD FREEZE WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING FOR
THE FOLLOWING ZONES...NMZ519-520-530>538.
FREEZE WARNING FROM 2 AM TO 10 AM MDT THURSDAY FOR THE FOLLOWING
ZONES...NMZ519-520-534>536.
WIND ADVISORY UNTIL 6 AM MDT THURSDAY FOR THE FOLLOWING ZONES...
NMZ534-535.
HIGH WIND WARNING UNTIL 9 PM MDT THIS EVENING FOR THE FOLLOWING
ZONES...NMZ525-526-539-540.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT THURSDAY FOR THE FOLLOWING
ZONES...NMZ510-512>514.
&&
$$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
654 PM EDT TUE APR 16 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE REGION THIS EVENING ACCOMPANIED
BY RAIN SHOWERS. A RIDGE OF HIGH PRESSURE WILL BUILD SOUTH INTO
THE REGION FROM CANADA ON WEDNESDAY. A WARM FRONT WILL APPROACH
THE REGION ON THURSDAY. IT WILL WARM AND WINDY FRIDAY FOLLOWED BY
SHOWERS FRIDAY NIGHT AS ANOTHER COLD FRONT MOVES ACROSS THE NORTH
COUNTRY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 654 PM EDT TUESDAY...PRE-FRONTAL RAIN SHOWERS HAVE EXITED
THE NORTH COUNTRY...THOUGH RECENT COMPOSITE RADAR SHOWS A FAIRLY
SOLID LINE OF RAIN SHOWERS APPROACHING THE SAINT LAWRENCE VALLEY
AND NORTHERN ADIRONDACKS OF NEW YORK. THESE SHOWERS ARE TIED TO
THE COLD FRONT AND HAVE GONE WITH AREAL COVERAGE WORDING TO HANDLE
THESE SHOWERS AS THEY MOVE ACROSS THE NORTH COUNTRY. RAP ANALYSES
SHOW A 85-95KT MID-LEVEL JET STREAK ORIENTED NORMAL TO THE SFC
BOUNDARY WHICH SUGGESTS THAT THE FRONT WILL BE QUICK TO MOVE EAST.
EXPECT THAT THESE SHOWERS WILL CONTINUE TO PROGRESS STEADILY
EASTWARD...CLEARING THE NORTH COUNTRY AROUND 05Z OR SO. THERE
COULD BE SOME BRIEF DOWNPOURS WITH THESE SHOWERS AS THEY MOVE
EAST...THOUGH QPF AMOUNTS SHOULD BE ON THE LIGHT SIDE. BEST
INSTABILITY REMAINS WELL SOUTH SO NOT EXPECTING ANY THUNDER WITH
THIS ACTIVITY.
A SHARP WIND SHIFT TO WEST/WEST-NORTHWEST IS EXPECTED WITH
CLEARING SKIES AND A NOTICEABLY DRIER AIRMASS FILTERING INTO THE
REGION. UNTIL THAT TIME...HAVE RAISED DEWPOINTS UP SEVERAL DEGREES
WITH DRYING OCCURRING WITH THE FRONT THEREAFTER. HAVE LEFT
TEMPERATURES LARGELY UNCHANGED AND WILL EVALUATE AS THE EVENING
PROGRESSES.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 357 PM EDT TUESDAY...HIGH PRESSURE WILL BUILD INTO THE REGION
ON WEDNESDAY. CENTER OF THE HIGH REMAINS OVER THE JAMES BAY REGION
WITH SEASONABLY COOL NORTHERLY FLOW EXPECTED ACROSS THE NORTH
COUNTRY. THUS...TEMPERATURES WILL BE A LITTLE LOWER THAN ON TUESDAY
WITH HIGHS IN THE 50S. DRY WEATHER CONTINUES WEDNESDAY NIGHT
ALTHOUGH THERE WILL BE AN INCREASE IN CLOUDS WITH ONSET OF WARM AIR
ADVECTION AS HIGH PRESSURE MOVES FURTHER EAST AND RETURN SOUTHERLY
FLOW DEVELOPS BY THURSDAY MORNING. A WARM FRONT WILL APPROACH THE
REGION ON THURSDAY. HAVE GONE WITH CHANCE POPS FOR A FEW
SHOWERS...MAINLY OVER NORTHERN ZONES. DESPITE CLOUD
COVER...INCREASING SOUTHERLY FLOW WILL ALLOW FOR MILDER
TEMPS...WITH HIGHS WELL INTO THE 50S TO LOWER 60S. FURTHER
INCREASE IN SOUTHERLY FLOW THURSDAY NIGHT...SO EXPECT A MILD NIGHT
AND MAINLY DRY AS FORECAST AREA WILL BE IN WARM SECTOR.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 355 PM EDT TUESDAY...CONSISTENT FORECAST CONTINUES WITH
WARM MAX TEMPERATURES ON FRIDAY AS 850MB TEMPS INCREASE TO ABOUT
10C-12C. SOUTHERLY FLOW...WAA AND SOME BREAKS IN CLOUDS WILL WARM
SFC TEMPS INTO THE 60S AND L70S.
A COLD FRONT WILL APPROACH FROM THE WEST ON THE LATTER HALF OF
FRIDAY INTO FRIDAY NIGHT. THIS FRONT COULD TRIGGER SOME ISOLATED
TS...BUT PARAMETERS NOT QUITE LINING UP TIME-WISE. TEMP LAPSE
RATES OF 6+C/KM LOWERING AS AREA OF CAPE MOVES EASTWARD INTO NRN
NY. ALSO LIFTED INDICES STAYING ABOVE ZERO...SO HAVE NOT INCLUDED
TS IN FCST AT THIS TIME. WITH THIS SYSTEM...GEFS SHOWING PWATS
VALUES OF 2-3 STANDARD DEVIATIONS ABOVE NORMAL OVER THE NORTH
COUNTRY...WITH QPF AMOUNTS UP TO A HALF INCH THROUGH SATURDAY.
PRECIP AND COLD FRONT SHOULD EXIT ERN VT SOMETIME ON
SATURDAY...FOLLOWED BY HIGH PRESSURE BUILDING INTO THE GREAT
LAKES REGION. THIS RIDGE OF HIGH PRESSURE WILL CREST OVER THE
REGION SUNDAY NIGHT AND SLIDE EAST OVER NOVA SCOTIA ON MONDAY.
DRY CONDITIONS WILL LINGER INTO THE BEGINNING OF NEXT WEEK.
TEMPERATURES STARTING WARM WITH WAA AND SOUTHERLY FLOW AHEAD OF
THE COLD FRONT. A GENERAL COOLING TREND OVER THE WEEKEND BEHIND
THE FRONT. FRIDAY NT MIN TEMPS WILL BE IN THE 40S. SATURDAY AND
SUNDAY MAX TEMPS WILL BE IN THE 40S TO L50S. SATURDAY NT AND
SUNDAY NT EXPECT BELOW NORMAL MIN TEMPS IN THE L20S-L30S. TEMPS
WILL WARM SLIGHTLY AS THE HIGH PRESSURE CRESTS OVER THE REGION
AND WE GET A RETURN TO SOUTHERLY FLOW. MONDAY MAX TEMPS WILL
REACH THE M40S-U50S AND MIN TEMPS MONDAY NIGHT WILL BE IN THE
M20S-M30S.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 18Z WEDNESDAY...GUSTY SOUTHERLY WINDS WILL CONTINUE INTO
THIS EVENING AS LLJ REMAINS OVER THE NORTH COUNTRY. PRECIP HAS
MOVED OVER KMSS AND KSLK WITH MVFR CIGS AT KSLK. SO MAINLY VFR
CONDITIONS WILL SEE MVFR CIGS AND OCCASIONAL MVFR VSBYS IN RAIN
SHOWERS THIS AFTERNOON AND EARLY EVENING AS A COLD FRONT MOVES
EASTWARD THROUGH THE AREA. RAIN WILL GENERALLY BE LIGHT.
BEHIND THE FRONT...WINDS WILL SHIFT MORE WESTERLY AND WIND GUSTS
WILL TAPER DOWN TO 15-25 KTS. OVERNIGHT...MAINLY AFTER
06Z...SKIES WILL BEGIN TO CLEAR OUT AND GUSTS WILL FADE...LEAVING
NW WINDS AT 5-10 KTS.
APPROACHING WEDNESDAY MORNING...WINDS WILL PICK UP AT 8-12KTS OUT
OF THE NW WITH MAINLY CLEAR SKIES.
OUTLOOK 18Z WEDNESDAY THROUGH SUNDAY...
18Z WEDNESDAY THROUGH 12Z THURSDAY...VFR CONDITIONS EXPECTED AS A
RIDGE OF HIGH PRESSURE WILL BE OVER THE REGION.
12Z THURSDAY THROUGH 00Z FRIDAY...VFR/AREAS OF MVFR POSSIBLE AS A
WARM FRONT WILL BRING A CHANCE OF RAIN SHOWERS TO NY. VFR
EXPECTED OVER VT.
00Z FRIDAY THROUGH 00Z SATURDAY...MAINLY VFR CONDITIONS EXPECTED.
00Z SATURDAY THROUGH 00Z SUNDAY...VFR/MVFR CONDITIONS AS COLD
FRONT BRINGS RAIN ACROSS THE NORTH COUNTRY.
00Z SUNDAY ONWARD...VFR CONDITIONS AS HIGH PRESSURE BUILDS INTO
THE REGION.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RJS
NEAR TERM...RJS/LOCONTO
SHORT TERM...RJS
LONG TERM...KGM
AVIATION...KGM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
144 PM EDT TUE APR 16 2013
.SYNOPSIS...
SOUTHERLY WIND WILL CONTINUE TO BRING CLOUDS AND THEN INCREASING
CHANCES OF SHOWERS FROM THE WEST LATER THIS MORNING. A COLD FRONT
WILL MOVE ACROSS CENTRAL NEW YORK THIS AFTERNOON...AND INTO
NORTHEAST PENNSYLVANIA THIS EVENING WITH SHOWERS AND A SLIGHT
CHANCE OF THUNDERSTORMS. ANY STORMS THAT FORM MAY CONTAIN GUSTY
WINDS. SHOWERS WILL END OVERNIGHT...LEAVING WEDNESDAY DRY. WARMER
AIR WILL RETURN TO THE REGION FOR THURSDAY...FOLLOWED BY A STRONG
COLD FRONT FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
115 PM UPDATE...
FIRST BATCH OF RAIN CURRENTLY MOVING THROUGH THE REGION WHICH
APPEARS TO ASSOCIATED WITH A WEAK SHORTWAVE MOVING OVERHEAD.
LIGHTNING ACTIVITY WITH THIS FIRST CLUSTER HAS DECREASED MARKEDLY
WITH PROGRESSION THROUGH THE CWA SIGNIFYING THE CURRENT STABILITY
OF THE ATMOSPHERE. ATTENTION NOW FOCUSED ON UPSTREAM LOCATIONS
ACROSS THE WESTERN FINGER LAKES AND WESTERN SOUTHERN TIER WHERE
RECENT VIS SATELLITE TRENDS HAVE SHOWN SOME PARTIAL BREAKS IN THE
OVERLYING CLOUD COVER. LATEST RUC MLCAPE FIELDS SHOWING LATTERLY
NO INSTABILITY ACROSS UPSTATE NY THIS HR BUT HIGH-RES MODELS DO
SUGGEST A WEAK LINE FORMING ALONG THE FRONT AS IT PUSHES THROUGH
LATER THIS AFTERNOON. AS SUCH...WILL CONTINUE TO ADVERTISE A SLGT
CHC THUNDER MENTION THIS AFTERNOON/EARLY EVENING BEFORE HIGH
PRESSURE BUILDING SOUTH FROM SOUTHERN CANADA LEADS TO DRIER AIR
AND A NORTH TO SOUTH REDUCTION IN PRECIP DURING THE EVENING HRS.
MAX TEMPS ADJUSTED SLIGHTLY BASED ON CURRENT RAIN ACTIVITY MOVING
THROUGH THE AREA BUT LOW TO MID 60S STILL LOOK REASONABLE. NO
OTHER CHANGES NEEDED AT THE PRESENT TIME.
10 AM UPDATE...
MAIN CONCERN HEADING INTO THE AFTERNOON CONTINUES TO BE CONVECTIVE
DEVELOPMENT AND A LIMITED SEVERE POTENTIAL AS KINEMATIC FIELDS
REMAIN MORE THAN SUPPORTIVE FOR SEVERE WX SUSTAINMENT. THAT
SAID...MAIN LIMITING FACTOR CONTINUES TO BE EXTENSIVE CLOUD COVER
WHICH IS VIEWABLE ON LATEST VIS SATELLITE PICS THIS MORNING WHICH
WILL UNDOUBTEDLY PREVENT MAX TEMPS FROM WARMING TO THEIR MAX
POTENTIAL THIS AFTERNOON. LATEST REGIONAL RADAR TRENDS NOW SHOWING
AN AREA OF SHWRS/EMBEDDED THUNDER APPROACHING THE WESTERN SOUTHERN
TIER AND 1-HR GRIDS HAVE BEEN UPDATED TO REFLECT CURRENT ACTIVITY.
WITH ANY CLEARING DISPLACED WELL TO OUR SOUTHWEST NEAR
PITTSBURGH...ITS HARD AT THIS POINT TO SURMISE THAT REGION WILL
SEE ANY APPRECIABLE CLEARING/DESTABILIZATION PRIOR TO FROPA LATER
THIS AFTERNOON. THAT BEING SAID...WILL LEAVE A SLGT CHC THUNDER
MENTION THROUGH THIS AFTERNOON AS FRONT SLOWLY MOVES THROUGH THE
FCST AREA. CURRENT THINKING IS APPROACHING PREFERENTIAL ACTIVITY
ACROSS THE WESTERN SOUTHERN TIER WILL LIKELY STABILIZE THE LOW-
LEVEL ENVIRONMENT EVEN FURTHER WHICH WILL LIKELY KEEP ANY SEVERE
WX DEVELOPMENT IN CHECK. WILL HAVE TO WATCH MOISTURE POOLING (LOW
50 DEW POINTS) ALONG THE BOUNDARY AS IT MOVES THROUGH BUT WITH MAX
MID/UPPER-LEVEL FORCING REMAIN DISPLACED WELL TO THE
NORTH...OVERALL SEVERE WX THREAT LOOKS VERY MARGINAL AT THIS TIME.
7 AM UPDATE... FORECAST DETAILS TWEAKED WHERE NEEDED...EXPECTATIONS
AND CONCERNS FOR FRONT THIS AFTERNOON/EVENING REMAIN THE SAME AS
DISCUSSED BELOW.
PREVIOUS DISCUSSION...
WE HAVE HAD A MILD NIGHT WITH SOUTHEAST TO SOUTH FLOW. MANY
LOCATIONS NOT ALREADY IN THE 50S WILL BE WITHIN THE NEXT FEW
HOURS...THOUGH CATSKILLS/POCONOS EASTWARD WILL HOLD ON TO 40S THE
LONGEST DUE TO MARINE-INFLUENCED LAYER. WATER VAPOR IMAGERY SHOWS
STORMS THAT BLEW UP ACROSS MISSOURI/ILLINOIS AND HEADING INTO
INDIANA...ASSOCIATED WITH A SHORTWAVE THAT WILL BE A PLAYER IN OUR
WEATHER LATER TODAY. FOR NOW...STILL DRY.
MODELS EARLIER STRUGGLED WITH THE LEAD SHORTWAVE...BUT LATEST
RUNS HAVE CAUGHT ON TO IT AND AS PER VORTICITY FIELDS BRING THE
WAVE THROUGH OUR REGION 15Z-19Z. AT THIS TIME I FEEL THERE WILL BE
A FAIR BATCH OF SHOWERS MOVING IN ASSOCIATED WITH THAT
WAVE...ESPECIALLY CENTRAL TO NORTHWEST ZONES...WHICH WILL RUN WELL
AHEAD OF THE SURFACE FRONT. THE CLOUDS FROM THIS WAVE WILL
PROBABLY FURTHER INHIBIT THE ALREADY LIMITED INSTABILITY FOR
CONVECTION THIS AFTERNOON/EVENING. ALSO...THE CLOUD COVER WILL
ALSO HELP TO KEEP THE STRONG LOW LEVEL JET...40-55 KTS AT
850MB...FROM EFFECTIVELY MIXING DOWN TO THE SURFACE. THAT BEING
SAID...STILL EXPECT A PRETTY GOOD BREEZE TODAY...INCLUDING GUSTS
REACHING 20-30 MPH IN NEPA /ESPECIALLY HIGHER ELEVS/ AND 25-35 MPH
IN CENTRAL NY. LAKE PLAIN AND SYRACUSE IN PARTICULAR COULD HAVE
SOME FAIRLY STRONG DOWNSLOPING GUSTS...PERHAPS ONE OR TWO AROUND
40 MPH BUT NOT FREQUENTLY BEYOND THAT SO NO WIND ADVISORY SEEMS
WARRANTED.
MODELS ARE WELL CONVERGED ON TIMING OF SURFACE FRONT...AGAIN JUST
SLIGHTLY DELAYED FROM PRIOR MODEL RUNS...FROM CORNING-SYRACUSE
AREA 21Z...TO TOWANDA-BINGHAMTON-ONEONTA 00Z...AND THEN EXITING
SOUTHEAST OF MONTICELLO-SCRANTON BY AROUND 03Z OR SO. INSTABILITY
WILL ONLY BE MARGINAL...AN AXIS RANGING FROM VERY LITTLE TO A FEW
HUNDRED J/KG OR SO IN THE MODELS. I HAVE FOCUSED OUR SLIGHT TO LOW
CHANCE OF THUNDER TO DIRECTLY WITH THE FRONT ITSELF WHERE THERE IS
GREAT LOW LEVEL CONVERGENCE. THE LEAD SHORTWAVE MAY INTERFERE
WITH HEATING...PROBABLY AT LEAST SOMEWHAT INHIBITING INSTABILITY
FROM BEING FULLY REALIZED. WE ARE CURRENTLY NOT PEGGED FOR SLIGHT
RISK OF SEVERE BY THE STORM PREDICTION CENTER...IN FACT NOT EVEN
IN THE GENERAL THUNDER OUTLOOK AS OF 430 AM...BUT THINGS WILL
NEED TO BE MONITORED CLOSELY BECAUSE SHOULD CONVECTION GET WELL
ORGANIZED ALONG THE FRONT...A GOOD AMOUNT OF SHEAR COULD LEAD TO
STRONG GUSTS. 0-1 KM SHEAR ALONG FRONT IN THE NAM IS 30-40 KTS.
SHOWERS WILL DIMINISH FAIRLY QUICKLY BEHIND THE FRONT OVERNIGHT.
DESPITE PRECIPITABLE WATER VALUES GETTING A BIT PAST 1.25 INCHES
ALONG THE FRONT...THINGS WILL MOVE THROUGH QUICKLY ENOUGH
CONSIDERING THE FLOW ALOFT AND PACE OF FRONT...TO LIMIT AREAL
AVERAGE RAIN AMOUNTS TO A FEW TENTHS OF AN INCH IN NEPA AND
BETWEEN QUARTER AND HALF INCH IN CENTRAL NY TODAY THROUGH TONIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
445 AM UPDATE...
HIGH PRESSURE TEMPORARILY TAKES CHARGE WEDNESDAY...WITH SHALLOW
POOL OF COOLER STABLE POST-FRONTAL AIR. A DECENT DAY WITH HIGH
TEMPERATURES STILL NEAR CLIMATOLOGY IF NOT EVEN A TOUCH ABOVE.
FRONTAL ZONE WILL BE SITUATED TO OUR SOUTH...BUT CLOSE ENOUGH FOR MID
TO HIGH LEVEL CLOUDS TO HANG AROUND FOR THE SOUTHERN ZONES.
TOWARDS LAKE PLAIN AND MOHAWK VALLEY...PLENTY OF SUN.
FRONTAL ZONE LIFTS BACK NORTHWARD WEDNESDAY NIGHT...WITH CLOUDS
BUT ONLY SLIGHT TO LOW CHANCES OF LIGHT SHOWERS DUE TO UPPER
RIDGING AND THUS LACK OF LIFT. THIS OPENS THE DOOR TO WARM RETURN
FLOW AGAIN THURSDAY...WITH EXPECTED HIGHS IN THE 60S TO LOW
70S /WARMEST FOR LAKE PLAIN TO SYRACUSE COURTESY OF DOWNSLOPING/.
1000-500MB THICKNESSES SURGE INTO THE 560S DECAMETER RANGE.
THURSDAY LOOKS MAINLY DRY...BUT WITH A CAVEAT. WITH UPPER RIDGE
AXIS ALREADY SHIFTING EAST THURSDAY...WE GET ON EDGE OF QUICK
SOUTHWESTERLY FLOW WHICH MAY BE RIDDLED WITH LITTLE SHORTWAVES.
ODDLY ENOUGH...THE 00Z NAM EVEN SUGGESTS ONE OF THOSE WAVES
IMPACTING THE CENTRAL SOUTHERN TIER THURSDAY EVENING WITH SHOWERS
COUPLED WITH INSTABILITY. 06Z NAM THOUGH IS BACKING OFF THIS
IDEA...WHILE OTHER MODELS KEEP INSTABILITY MUCH FARTHER WEST DUE
TO FAIRLY STABLE LOW LEVELS FROM EARLIER MARINE-INFLUENCED LAYER
ADVECTING IN WEDNESDAY NIGHT/THURSDAY.
MAINLY 50S FOR LOWS THURSDAY NIGHT...WITH ONLY SLIGHT CHANCE POPS
AT BEST...AS WE AWAIT NEXT PROGRESSIVE COLD FRONT WHICH WILL STILL
BE WELL TO THE WEST /BUT INBOUND FOR FRIDAY/.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
3 PM MON UPDATE... ONLY MINIMAL CHGS MADE TO THE GRIDS ATTM...AS
THE LARGE-SCALE PATN IN THE MODELS REMAINS SIMILAR.
THE MAIN FEATURE TO WATCH EARLY IN THE PD IS A FAIRLY STG AND
PROGRESSIVE COLD FRNT...SLATED TO COME THROUGH NY/PA BY FRI EVE.
WE`LL CONTINUE TO ADVERTISE LIKELY POPS THIS PD FOR SHWRS.
CONVECTIVE EVOLUTION REMAINS UNCERTAIN...OWING TO THE DEGREE OF
DESTABILIZATION AHD OF THE FRNT. FOR NOW...WE`VE THROWN IN A CHC
OF TSTMS...TO GO ALG WITH THE LIKELIHOOD OF SHWRS.
AFTERWARDS...DRIER AIR WILL GRADUALLY FILTER IN...AS A SFC HIGH
BUILDS OUT OF S-CNTRL CANADA. A FEW -SHRA/SPRINKLES COULD LINGER
FRI NGT...PERHAPS EVEN INTO EARLY SAT...UNDERNEATH THE SRN END
OF AN UPR-LVL TROUGH. OTHWS...THOUGH...THE WEEKEND INTO EARLY NEXT
WEEK LOOKS DRY AND COOL...FROM THIS EARLY VANTAGE PT.
PREV DISC... THE PERIOD BEGINS WITH A JET DIGGING A SHARP TROF
INTO THE SOUTHERN PLAINS, BRINGING MUCH BELOW AVERAGE TEMPS TO THE
CENTRAL U.S. AN EASTERN RIDGE DEVELOPS IN RESPONSE, WITH AN ACTIVE
WEATHER PATTERN DEVELOPING IN THE SOUTHWESTERLY FLOW UP THE BACK
SIDE OF THE RIDGE FROM IL/MO TO THE LOWER GREAT LAKES.
STORMS RIDING UP THROUGH THE GREAT LAKES WILL HELP PULL WARM/MOIST
AIR INTO NY/PA. THIS WILL LEAD TO A SHOWERY, MILD PATTERN AT THE
ONSET OF THE LONG TERM PERIOD. A GREAT LAKES CYCLONE INTENSIFIES
OVER NORTHERN MICHIGAN ON FRIDAY, WHILE AN ATLANTIC ANTICYCLONE
BUILDS. PRESSURE GRADIENT STRENGTHENS AS A RESULT THROUGH NY/PA.
PRECIPITATION TIMING AND CLOUD COVER WILL HAVE A LOT TO SAY ABOUT
MAX TEMPS COME FRIDAY. 925MB TEMPS OF 15-17C ARE PROGGED BY ECMWF
TO EXTEND THROUGH UPSTATE NY BY 18Z. CLOUDS ARE LIKELY TO SUPPRESS
MAXES, BUT ANY BREAKS WILL ALLOW TEMPS TO PUSH THROUGH THE 70S AND
ENHANCE INSTABILITY AHEAD OF COLD FRONT. UNTIL INSTABILITY CAN BE
BETTER PROGGED, WILL STICK TO FORECAST FOR SHOWERS AND JUST A
CHANCE OF THUNDER.
COOLER/DRIER AIR FOLLOWS THE COLD FRONT FOR THE WEEKEND.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
18Z TUE UPDATE... MVFR RESTRICTIONS ARE EXPECTED MUCH OF THE TIME
THIS AFTN (LWR CIGS/SCTD -SHRA).
A NARROW LINE/BAND OF SHRA IS EXPECTED TO ACCOMPANY A FROPA EARLY
THIS EVE (23Z-03Z)...WITH SOME IFR PSBL AT KBGM/KITH...WHILE MVFR
SHOULD CONTINUE TO BE THE PREDOMINANT CONDITION ELSEWHERE. BEHIND
THE FRNT...LWR CLDS WILL PERSIST FOR A TIME (AGN IFR PROBABLE ON
THE HILLTOPS AT KBGM/KITH...WITH MVFR ELSEWHERE).
LTR TNT...DRIER AIR WILL PUSH DOWN FROM THE NW...WITH AT LEAST PTL
CLEARING ANTICIPATED...AND A RETURN TO VFR AREA-WIDE. VFR SHOULD
THEN CONTINUE THROUGH 18Z WED.
GUSTY SRLY WINDS THROUGH EARLY EVE (UP TO 20-25 KT)...WILL SHIFT
INTO THE NW AND N OVERNIGHT AND WED.
.OUTLOOK...
WED NGT THROUGH SUN...MOSTLY VFR. LWR CIGS PSBL THU/FRI AM...AND
RESTRICTIONS PSBL FROM SHRA/TSRA FRI AFTN/EVE.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...CMG/MDP
SHORT TERM...MDP
LONG TERM...DJP/MLJ
AVIATION...MLJ/MSE
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
130 PM EDT TUE APR 16 2013
.SYNOPSIS...
SOUTHERLY WIND WILL CONTINUE TO BRING CLOUDS AND THEN INCREASING
CHANCES OF SHOWERS FROM THE WEST LATER THIS MORNING. A COLD FRONT
WILL MOVE ACROSS CENTRAL NEW YORK THIS AFTERNOON...AND INTO
NORTHEAST PENNSYLVANIA THIS EVENING WITH SHOWERS AND A SLIGHT
CHANCE OF THUNDERSTORMS. ANY STORMS THAT FORM MAY CONTAIN GUSTY
WINDS. SHOWERS WILL END OVERNIGHT...LEAVING WEDNESDAY DRY. WARMER
AIR WILL RETURN TO THE REGION FOR THURSDAY...FOLLOWED BY A STRONG
COLD FRONT FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
115 PM UPDATE...
FIRST BATCH OF RAIN CURRENTLY MOVING THROUGH THE REGION WHICH
APPEARS TO ASSOCIATED WITH A WEAK SHORTWAVE MOVING OVERHEAD.
LIGHTNING ACTIVITY WITH THIS FIRST CLUSTER HAS DECREASED MARKEDLY
WITH PROGRESSION THROUGH THE CWA SIGNIFYING THE CURRENT STABILITY
OF THE ATMOSPHERE. ATTENTION NOW FOCUSED ON UPSTREAM LOCATIONS
ACROSS THE WESTERN FINGER LAKES AND WESTERN SOUTHERN TIER WHERE
RECENT VIS SATELLITE TRENDS HAVE SHOWN SOME PARTIAL BREAKS IN THE
OVERLYING CLOUD COVER. LATEST RUC MLCAPE FIELDS SHOWING LATTERLY
NO INSTABILITY ACROSS UPSTATE NY THIS HR BUT HIGH-RES MODELS DO
SUGGEST A WEAK LINE FORMING ALONG THE FRONT AS IT PUSHES THROUGH
LATER THIS AFTERNOON. AS SUCH...WILL CONTINUE TO ADVERTISE A SLGT
CHC THUNDER MENTION THIS AFTERNOON/EARLY EVENING BEFORE HIGH
PRESSURE BUILDING SOUTH FROM SOUTHERN CANADA LEADS TO DRIER AIR
AND A NORTH TO SOUTH REDUCTION IN PRECIP DURING THE EVENING HRS.
MAX TEMPS ADJUSTED SLIGHTLY BASED ON CURRENT RAIN ACTIVITY MOVING
THROUGH THE AREA BUT LOW TO MID 60S STILL LOOK REASONABLE. NO
OTHER CHANGES NEEDED AT THE PRESENT TIME.
10 AM UPDATE...
MAIN CONCERN HEADING INTO THE AFTERNOON CONTINUES TO BE CONVECTIVE
DEVELOPMENT AND A LIMITED SEVERE POTENTIAL AS KINEMATIC FIELDS
REMAIN MORE THAN SUPPORTIVE FOR SEVERE WX SUSTAINMENT. THAT
SAID...MAIN LIMITING FACTOR CONTINUES TO BE EXTENSIVE CLOUD COVER
WHICH IS VIEWABLE ON LATEST VIS SATELLITE PICS THIS MORNING WHICH
WILL UNDOUBTEDLY PREVENT MAX TEMPS FROM WARMING TO THEIR MAX
POTENTIAL THIS AFTERNOON. LATEST REGIONAL RADAR TRENDS NOW SHOWING
AN AREA OF SHWRS/EMBEDDED THUNDER APPROACHING THE WESTERN SOUTHERN
TIER AND 1-HR GRIDS HAVE BEEN UPDATED TO REFLECT CURRENT ACTIVITY.
WITH ANY CLEARING DISPLACED WELL TO OUR SOUTHWEST NEAR
PITTSBURGH...ITS HARD AT THIS POINT TO SURMISE THAT REGION WILL
SEE ANY APPRECIABLE CLEARING/DESTABILIZATION PRIOR TO FROPA LATER
THIS AFTERNOON. THAT BEING SAID...WILL LEAVE A SLGT CHC THUNDER
MENTION THROUGH THIS AFTERNOON AS FRONT SLOWLY MOVES THROUGH THE
FCST AREA. CURRENT THINKING IS APPROACHING PREFERENTIAL ACTIVITY
ACROSS THE WESTERN SOUTHERN TIER WILL LIKELY STABILIZE THE LOW-
LEVEL ENVIRONMENT EVEN FURTHER WHICH WILL LIKELY KEEP ANY SEVERE
WX DEVELOPMENT IN CHECK. WILL HAVE TO WATCH MOISTURE POOLING (LOW
50 DEWPOINTS) ALONG THE BOUNDARY AS IT MOVES THROUGH BUT WITH MAX
MID/UPPER-LEVEL FORCING REMAIN DISPLACED WELL TO THE
NORTH...OVERALL SEVERE WX THREAT LOOKS VERY MARGINAL AT THIS TIME.
7 AM UPDATE... FORECAST DETAILS TWEAKED WHERE NEEDED...EXPECTATIONS
AND CONCERNS FOR FRONT THIS AFTERNOON/EVENING REMAIN THE SAME AS
DISCUSSED BELOW.
PREVIOUS DISCUSSION...
WE HAVE HAD A MILD NIGHT WITH SOUTHEAST TO SOUTH FLOW. MANY
LOCATIONS NOT ALREADY IN THE 50S WILL BE WITHIN THE NEXT FEW
HOURS...THOUGH CATSKILLS/POCONOS EASTWARD WILL HOLD ON TO 40S THE
LONGEST DUE TO MARINE-INFLUENCED LAYER. WATER VAPOR IMAGERY SHOWS
STORMS THAT BLEW UP ACROSS MISSOURI/ILLINOIS AND HEADING INTO
INDIANA...ASSOCIATED WITH A SHORTWAVE THAT WILL BE A PLAYER IN OUR
WEATHER LATER TODAY. FOR NOW...STILL DRY.
MODELS EARLIER STRUGGLED WITH THE LEAD SHORTWAVE...BUT LATEST
RUNS HAVE CAUGHT ON TO IT AND AS PER VORTICITY FIELDS BRING THE
WAVE THROUGH OUR REGION 15Z-19Z. AT THIS TIME I FEEL THERE WILL BE
A FAIR BATCH OF SHOWERS MOVING IN ASSOCIATED WITH THAT
WAVE...ESPECIALLY CENTRAL TO NORTHWEST ZONES...WHICH WILL RUN WELL
AHEAD OF THE SURFACE FRONT. THE CLOUDS FROM THIS WAVE WILL
PROBABLY FURTHER INHIBIT THE ALREADY LIMITED INSTABILITY FOR
CONVECTION THIS AFTERNOON/EVENING. ALSO...THE CLOUD COVER WILL
ALSO HELP TO KEEP THE STRONG LOW LEVEL JET...40-55 KTS AT
850MB...FROM EFFECTIVELY MIXING DOWN TO THE SURFACE. THAT BEING
SAID...STILL EXPECT A PRETTY GOOD BREEZE TODAY...INCLUDING GUSTS
REACHING 20-30 MPH IN NEPA /ESPECIALLY HIGHER ELEVS/ AND 25-35 MPH
IN CENTRAL NY. LAKE PLAIN AND SYRACUSE IN PARTICULAR COULD HAVE
SOME FAIRLY STRONG DOWNSLOPING GUSTS...PERHAPS ONE OR TWO AROUND
40 MPH BUT NOT FREQUENTLY BEYOND THAT SO NO WIND ADVISORY SEEMS
WARRANTED.
MODELS ARE WELL CONVERGED ON TIMING OF SURFACE FRONT...AGAIN JUST
SLIGHTLY DELAYED FROM PRIOR MODEL RUNS...FROM CORNING-SYRACUSE
AREA 21Z...TO TOWANDA-BINGHAMTON-ONEONTA 00Z...AND THEN EXITING
SOUTHEAST OF MONTICELLO-SCRANTON BY AROUND 03Z OR SO. INSTABILITY
WILL ONLY BE MARGINAL...AN AXIS RANGING FROM VERY LITTLE TO A FEW
HUNDRED J/KG OR SO IN THE MODELS. I HAVE FOCUSED OUR SLIGHT TO LOW
CHANCE OF THUNDER TO DIRECTLY WITH THE FRONT ITSELF WHERE THERE IS
GREAT LOW LEVEL CONVERGENCE. THE LEAD SHORTWAVE MAY INTERFERE
WITH HEATING...PROBABLY AT LEAST SOMEWHAT INHIBITING INSTABILITY
FROM BEING FULLY REALIZED. WE ARE CURRENTLY NOT PEGGED FOR SLIGHT
RISK OF SEVERE BY THE STORM PREDICTION CENTER...IN FACT NOT EVEN
IN THE GENERAL THUNDER OUTLOOK AS OF 430 AM...BUT THINGS WILL
NEED TO BE MONITORED CLOSELY BECAUSE SHOULD CONVECTION GET WELL
ORGANIZED ALONG THE FRONT...A GOOD AMOUNT OF SHEAR COULD LEAD TO
STRONG GUSTS. 0-1 KM SHEAR ALONG FRONT IN THE NAM IS 30-40 KTS.
SHOWERS WILL DIMINISH FAIRLY QUICKLY BEHIND THE FRONT OVERNIGHT.
DESPITE PRECIPITABLE WATER VALUES GETTING A BIT PAST 1.25 INCHES
ALONG THE FRONT...THINGS WILL MOVE THROUGH QUICKLY ENOUGH
CONSIDERING THE FLOW ALOFT AND PACE OF FRONT...TO LIMIT AREAL
AVERAGE RAIN AMOUNTS TO A FEW TENTHS OF AN INCH IN NEPA AND
BETWEEN QUARTER AND HALF INCH IN CENTRAL NY TODAY THROUGH TONIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
445 AM UPDATE...
HIGH PRESSURE TEMPORARILY TAKES CHARGE WEDNESDAY...WITH SHALLOW
POOL OF COOLER STABLE POST-FRONTAL AIR. A DECENT DAY WITH HIGH
TEMPERATURES STILL NEAR CLIMATOLOGY IF NOT EVEN A TOUCH ABOVE.
FRONTAL ZONE WILL BE SITUATED TO OUR SOUTH...BUT CLOSE ENOUGH FOR MID
TO HIGH LEVEL CLOUDS TO HANG AROUND FOR THE SOUTHERN ZONES.
TOWARDS LAKE PLAIN AND MOHAWK VALLEY...PLENTY OF SUN.
FRONTAL ZONE LIFTS BACK NORTHWARD WEDNESDAY NIGHT...WITH CLOUDS
BUT ONLY SLIGHT TO LOW CHANCES OF LIGHT SHOWERS DUE TO UPPER
RIDGING AND THUS LACK OF LIFT. THIS OPENS THE DOOR TO WARM RETURN
FLOW AGAIN THURSDAY...WITH EXPECTED HIGHS IN THE 60S TO LOW
70S /WARMEST FOR LAKE PLAIN TO SYRACUSE COURTESY OF DOWNSLOPING/.
1000-500MB THICKNESSES SURGE INTO THE 560S DECAMETER RANGE.
THURSDAY LOOKS MAINLY DRY...BUT WITH A CAVEAT. WITH UPPER RIDGE
AXIS ALREADY SHIFTING EAST THURSDAY...WE GET ON EDGE OF QUICK
SOUTHWESTERLY FLOW WHICH MAY BE RIDDLED WITH LITTLE SHORTWAVES.
ODDLY ENOUGH...THE 00Z NAM EVEN SUGGESTS ONE OF THOSE WAVES
IMPACTING THE CENTRAL SOUTHERN TIER THURSDAY EVENING WITH SHOWERS
COUPLED WITH INSTABILITY. 06Z NAM THOUGH IS BACKING OFF THIS
IDEA...WHILE OTHER MODELS KEEP INSTABILITY MUCH FARTHER WEST DUE
TO FAIRLY STABLE LOW LEVELS FROM EARLIER MARINE-INFLUENCED LAYER
ADVECTING IN WEDNESDAY NIGHT/THURSDAY.
MAINLY 50S FOR LOWS THURSDAY NIGHT...WITH ONLY SLIGHT CHANCE POPS
AT BEST...AS WE AWAIT NEXT PROGRESSIVE COLD FRONT WHICH WILL STILL
BE WELL TO THE WEST /BUT INBOUND FOR FRIDAY/.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
3 PM MON UPDATE... ONLY MINIMAL CHGS MADE TO THE GRIDS ATTM...AS
THE LARGE-SCALE PATN IN THE MODELS REMAINS SIMILAR.
THE MAIN FEATURE TO WATCH EARLY IN THE PD IS A FAIRLY STG AND
PROGRESSIVE COLD FRNT...SLATED TO COME THROUGH NY/PA BY FRI EVE.
WE`LL CONTINUE TO ADVERTISE LIKELY POPS THIS PD FOR SHWRS.
CONVECTIVE EVOLUTION REMAINS UNCERTAIN...OWING TO THE DEGREE OF
DESTABILIZATION AHD OF THE FRNT. FOR NOW...WE`VE THROWN IN A CHC
OF TSTMS...TO GO ALG WITH THE LIKELIHOOD OF SHWRS.
AFTERWARDS...DRIER AIR WILL GRADUALLY FILTER IN...AS A SFC HIGH
BUILDS OUT OF S-CNTRL CANADA. A FEW -SHRA/SPRINKLES COULD LINGER
FRI NGT...PERHAPS EVEN INTO EARLY SAT...UNDERNEATH THE SRN END
OF AN UPR-LVL TROUGH. OTHWS...THOUGH...THE WEEKEND INTO EARLY NEXT
WEEK LOOKS DRY AND COOL...FROM THIS EARLY VANTAGE PT.
PREV DISC... THE PERIOD BEGINS WITH A JET DIGGING A SHARP TROF
INTO THE SOUTHERN PLAINS, BRINGING MUCH BELOW AVERAGE TEMPS TO THE
CENTRAL U.S. AN EASTERN RIDGE DEVELOPS IN RESPONSE, WITH AN ACTIVE
WEATHER PATTERN DEVELOPING IN THE SOUTHWESTERLY FLOW UP THE BACK
SIDE OF THE RIDGE FROM IL/MO TO THE LOWER GREAT LAKES.
STORMS RIDING UP THROUGH THE GREAT LAKES WILL HELP PULL WARM/MOIST
AIR INTO NY/PA. THIS WILL LEAD TO A SHOWERY, MILD PATTERN AT THE
ONSET OF THE LONG TERM PERIOD. A GREAT LAKES CYCLONE INTENSIFIES
OVER NORTHERN MICHIGAN ON FRIDAY, WHILE AN ATLANTIC ANTICYCLONE
BUILDS. PRESSURE GRADIENT STRENGTHENS AS A RESULT THROUGH NY/PA.
PRECIPITATION TIMING AND CLOUD COVER WILL HAVE A LOT TO SAY ABOUT
MAX TEMPS COME FRIDAY. 925MB TEMPS OF 15-17C ARE PROGGED BY ECMWF
TO EXTEND THROUGH UPSTATE NY BY 18Z. CLOUDS ARE LIKELY TO SUPPRESS
MAXES, BUT ANY BREAKS WILL ALLOW TEMPS TO PUSH THROUGH THE 70S AND
ENHANCE INSTABILITY AHEAD OF COLD FRONT. UNTIL INSTABILITY CAN BE
BETTER PROGGED, WILL STICK TO FORECAST FOR SHOWERS AND JUST A
CHANCE OF THUNDER.
COOLER/DRIER AIR FOLLOWS THE COLD FRONT FOR THE WEEKEND.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
DRY OVERCAST CONDITIONS ARE EXPECTED THROUGH THIS MORNING. CIGS
WILL BE MOSTLY VFR WITH OCCASIONAL MVFR AROUND 12Z AT ELM/BGM/AVP.
SHOWERS WILL DEVELOP BY EARLY AFTERNOON ACROSS NY STATE AND LATER
THIS AFTERNOON IN NORTHEAST PA. A FEW HVY DOWNPOURS WITH SOME
THUNDER AND LIGHTNING WILL BE POSSIBLE LATER THIS AFTERNOON
ESPECIALLY AT AVP... BUT DURATION AND PROBABILITY FOR THIS IS
SMALL ENOUGH SO THAT IT IS NOT INCLUDED IN THE TAFS AT THIS TIME.
SHOWERS WILL END TUESDAY EVENING WITH VFR CONDITIONS RETURNING.
WINDS WILL BE FROM THE SOUTH-SOUTHWEST INCREASING TO 10 TO 20 KTS
WITH GUSTS AS HIGH AS 30 KTS TODAY... SHIFTING TO NORTHWEST AT 10
TO 20 KTS LATE THIS AFTERNOON THROUGH THIS EVENING THEN
DIMINISHING TO LESS THAN 10 KTS LATER TUESDAY NIGHT.
.OUTLOOK...
WED THROUGH SAT...MOSTLY VFR. LWR CIGS PSBL THU/FRI AM...AND
RESTRICTIONS PSBL FROM SHRA/TSRA FRI AFTN/EVE.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...CMG/MDP
SHORT TERM...MDP
LONG TERM...DJP/MLJ
AVIATION...MSE
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1104 AM EDT TUE APR 16 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TODAY ALONG WITH SOME SHOWERS...
WITH A THUNDERSTORM ALSO POSSIBLE SOUTH OF BUFFALO AND ROCHESTER.
FOLLOWING THE FRONT...SEASONABLY COOLER WEATHER WILL RETURN FOR
TONIGHT AND WEDNESDAY...BEFORE MUCH WARMER AIR SURGES BACK INTO THE
REGION IN TIME FOR THURSDAY ALONG WITH THE CHANCE FOR SOME
ADDITIONAL SHOWERS.
&&
.NEAR TERM /THROUGH TONIGHT/...
DURING THE COURSE OF TODAY...LOW PRESSURE WILL TRACK ACROSS
CENTRAL QUEBEC PROVENCE AND RAPIDLY EJECT NORTHEASTWARD TO
LABRADOR...AND IN THE PROCESS WILL SLOWLY PUSH ITS TRAILING COLD
FRONT SOUTHEASTWARD ACROSS NEW YORK STATE. AT 1100 AM...THIS FRONT
WAS JUST NORTHWEST OF LAKE ERIE AND ONTARIO...WITH GOOD MODEL
AGREEMENT THAT THE FRONT WILL MOVE ACROSS WESTERN NEW YORK THIS
AFTERNOON.
RADAR SHOWS SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OUT AHEAD OF
THIS FRONTAL BOUNDARY...WITH STEADY SHOWERS ACROSS MOST OF NEW
YORK WEST OF ROCHESTER. WHILE SOME OF THE 00Z/06 GUIDANCE
STRUGGLED TO FORECAST EXACTLY WHERE CONVECTION WOULD BREAK
OUT...THE LATEST RUNS OF THE HRRR DEPICT CURRENT CONDITIONS
FAIRLY WELL...AND THUS PROVIDES FAIRLY GOOD GUIDANCE FOR THE
REMAINDER OF THE DAY. FOLLOWING THIS...EXPECT SHOWERS TO CONTINUE
TO MOVE RAPIDLY ENE...BRINGING AT LEAST SOME PRECIPITATION TO
NEARLY ALL OF THE REGION THROUGH EARLY AFTERNOON. HEAVIEST SHOWERS
WILL BE SOUTH...WHERE THERE STILL ARE QUITE A FEW LIGHTNING
STRIKES. THIS AREA SHOULD MOVE THROUGH RATHER RAPIDLY...BUT THE
HRRR (NOW WITH SUPPORT FROM THE 12Z NAM) SUGGESTS THAT ANOTHER
ROUND OF SHOWERS AND POSSIBLY THUNDERSTORMS WILL DEVELOP RIGHT ON
THE FRONT. TO DO THIS WILL TAKE A MODEST CONTRIBUTION FROM DAYTIME
HEATING ACROSS THE FINGER LAKES AND EASTERN LAKE ONTARIO
REGIONS...EXTENDING INTO CENTRAL PORTIONS OF THE STATE. IF THIS
DOES OCCUR...THIS WILL NOT DEVELOP UPSTREAM...RATHER SHOWERS WOULD
DEVELOP ACROSS THE ABOVE MENTIONED REGIONS LATE THIS AFTERNOON.
QPFS WILL VARY...WITH MOST AREAS LIKELY TO SEE A TENTH OF AN INCH
OR TWO...WITH LOCALLY HIGHER AMOUNTS TO A HALF INCH IN
THUNDERSTORMS.
OTHERWISE...THE DAY WILL GET OFF TO A WARM AND BREEZY START.
TEMPERATURES WILL REMAIN IN THE 60S AHEAD OF THE RAIN
SHOWERS...WITH HIGHS IN THE UPPER 60S LIKELY IN THE FINGER LAKES
REGION WHERE RAIN WILL HOLD OFF A BIT LONGER. MEANWHILE...SOUTHERLY
WINDS WILL CONTINUE TO GUST TO 30 TO 35 MPH IN MOST
LOCATIONS...WITH GUSTS TO 40 MPH ACROSS HIGHER TERRAIN AND IN THE
BLACK RIVER VALLEY.
LATE THIS AFTERNOON THROUGH TONIGHT...THE FRONTAL BOUNDARY WILL GET
SUPPRESSED FURTHER SOUTH TO THE MASON/DIXON LINE AS HIGH PRESSURE
AND MUCH DRIER AIR BRIEFLY RIDGES SOUTHEAST FROM NORTHERN ONTARIO
PROVINCE. FOR OUR AREA...THIS WILL RESULT IN ANY LINGERING SHOWER
CHANCES ENDING FROM NORTHWEST TO SOUTHEAST LATE THIS AFTERNOON AND
EVENING FOLLOWED BY DRY WEATHER THE REMAINDER OF THE NIGHT...THOUGH
SOME CLOUDS WILL LINGER ACROSS AREAS SOUTH OF LAKE ONTARIO...WHICH
WILL BE CLOSER TO THE SLOWLY DEPARTING FRONTAL ZONE. AS FOR TEMPS...
COOLER AIR FILTERING IN BEHIND THE FRONT WILL RESULT IN TEMPS
FALLING BACK TO THE UPPER 30S TO LOWER 40S SOUTH OF LAKE ONTARIO...
AND TO THE LOWER-MID 30S ACROSS THE NORTH COUNTRY WHERE THERE WILL
BE LESS CLOUD COVER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
A PROGRESSIVE HIGH AMPLITUDE FLOW WILL BE FOUND ACROSS THE UNITED
STATES DURING THIS PERIOD...WITH THE LOWER GREAT LAKES REGION BEING
FORTUNATE ENOUGH TO BE FOUND ON THE WARM SIDE OF AN EXPANSIVE RIDGE.
THIS WILL LEAD TO SEASONABLE CONDITIONS ON WEDNESDAY BEFORE
ANOMALOUS WARMTH RETURNS FOR THURSDAY AND FRIDAY. TEMPERATURES AT
THAT TIME COULD EASILY CLIMB TO MORE THAN 20 DEGREES F ABOVE NORMAL
VALUES. IT IS NOT OUT OF THE QUESTION THAT THE WARMER VALLEYS COULD
EVEN TICKLE THE 80 DEGREE MARK ON THURSDAY.
IN TERMS OF PCPN...THE BULK OF THIS PERIOD WILL BE RAIN-FREE. WHILE
THERE WILL BE THE CHANCE FOR SOME NUISANCE LIGHT SHOWERS AS THE
WARMER AIR WORKS INTO OUR REGION WEDNESDAY NIGHT AND THURSDAY...THE
HIGHEST CHANCE FOR ANY ADVERSE WEATHER WILL COME FRIDAY AFTERNOON
AND NIGHT WHEN A STRONG COLD FRONT WILL PLOW ACROSS THE LOWER GREAT
LAKES. THIS FEATURE COULD END UP GENERATING OUR FIRST WIDESPREAD
SEVERE WEATHER OUTBREAK. SOME DETAILS...
HIGH PRESSURE CENTERED OVER NORTHERN ONTARIO ON WEDNESDAY WILL ARCH
ACROSS THE LOWER GREAT LAKES AND NEW ENGLAND TO PROVIDE US WITH FAIR
SEASONABLE CONDITIONS. THE SUNNIEST CONDITIONS WILL BE FOUND ACROSS
THE EASTERN LAKE ONTARIO REGION WHILE SOME HIGH AND MID LEVEL CLOUDS
CAN BE EXPECTED OVER THE FAR WESTERN COUNTIES. GIVEN THE LIGHT
NORTHERLY FLOW...THE COOLEST WEATHER WILL LIKELY BE FOUND OVER THE
COUNTIES BORDERING THE SOUTH SHORE OF LK ONTARIO WHERE READINGS WILL
STRUGGLE INTO THE LOW 50S. ELSEWHERE...HIGHS SHOULD BE CLOSE TO
THEIR SEASONABLE NORMS OF 55 TO 60.
AS THE LARGE SFC HIGH MOVES EAST ACROSS QUEBEC WEDNESDAY NIGHT...A
DEEP INVERTED TROUGH WILL EXTEND FROM THE CENTRAL PLAINS NORTHEAST
ACROSS THE UPPER GREAT LAKES. A DEEP SOUTHERLY FLOW WILL DEVELOP
BETWEEN THESE SYSTEMS...WITH STRONG WARM ADVECTION FOUND OVER THE
GREAT LAKES REGION. THE LEADING EDGE OF THE WARMER AIRMASS (WARM
FRONT) MAY GENERATE SOME LIGHT SHOWERS/SPRINKLES ACROSS OUR FORECAST
AREA IN THE PROCESS...WITH MORE WIDESPREAD SHRA/TSRA REMAINING OVER
UPPER ONTARIO AND THE UPPER GREAT LAKES.
THE SOUTHERLY FLOW WILL INTENSIFY OVER THE LOWER GREAT LAKES AND
OHIO VALLEY ON THURSDAY AS THE AFOREMENTIONED WARM FRONT WILL LIFT
FROM THE THOUSAND ISLANDS REGION TO SOUTHERN QUEBEC. THIS WILL ALLOW
OUR SKIES TO PARTIALLY CLEAR DURING THE COURSE OF THURSDAY...MUCH
LIKE THEY DID YESTERDAY (MONDAY) WHEN TEMPERATURES REACHED INTO THE
70S. SPEAKING OF WHICH...H85 TEMPS WILL JUMP TO AROUND 14C BY
THURSDAY AFTERNOON AND THIS WILL EASILY SUPPORT DAYTIME HIGHS IN THE
MID 70S WITH 80 DEGREE READINGS NOT OUT OF THE QUESTION IN THE
WARMER VALLEYS.
WARM AND BREEZY CONDITIONS WILL THEN BE FOUND ACROSS THE FORECAST
AREA THURSDAY NIGHT AS DEEPENING LOW PRESSURE WILL LIFT TO LOWER
MICHIGAN WHILE SWEEPING A STRONG COLD FRONT AND ITS ASSOCIATED
SEVERE WEATHER ACROSS THE OHIO AND TENNESSEE VALLEYS. FOR OUR REGION
THOUGH...WE SHOULD BE MAINLY DRY AND QUITE MILD WITH TEMPERATURES
HAVING TROUBLE FALLING BELOW 60. IT WILL BE A LITTLE ON THE HUMID
SIDE AS WELL...MAKING IT FEEL MORE LIKE A NIGHT IN MID-LATE JUNE.
FRIDAY WILL FEATURE VERY UNSETTLED WEATHER AS THE DEEP SFC LOW
TO OUR WEST WILL PUSH ITS STRONG COLD FRONT ACROSS MUCH OF OUR
REGION. FROM THIS VANTAGE POINT...GUIDANCE HAS BEEN CONSISTENT WITH
BRINGING THE FRONT ACROSS WESTERN NEW YORK DURING THE AFTERNOON AND
EVENING. IF THIS TIMING HOLDS UP...TEMPERATURES SHOULD BE ABLE TO
JUMP BACK INTO THE 70S BEFORE THE THICKER CLOUD COVER AND FRONTAL
PCPN MOVES IN. SPEAKING OF WHICH...GIVEN THE STRONG DYNAMICS OF THE
SYNOPTIC SYSTEM AND THE PRESENCE OF A 60-70KT LOW LEVEL JET...WOULD
ANTICIPATE AT LEAST THE THREAT FOR STRONG TO SEVERE THUNDERSTORMS
AHEAD/DURING THE FRONTAL PASSAGE. WHILE GUIDANCE IS NOT DEPICTING
SIGNIFICANT INSTABILITY...CONVECTION COULD EASILY BE SUPPORTED BY
THE STRENGTH OF THE UNDERLYING SYNOPTICS. THE WIND PROFILE AHEAD OF
THE FRONT DEPICTS ALOT OF SHEAR AS WELL...SO THIS IS A VALID
CONCERN. WILL MENTION THIS THREAT IN THE HAZARDOUS WEATHER OUTLOOK.
AS IF THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS IS NOT
ENOUGH...THE STRONG LOW LEVEL JET AND FAVORABLE TRACK OF THE DEEP
SFC LOW FROM LOWER MICHIGAN AND LAKE HURON TO SOUTHERN QUEBEC WILL
SET THE STAGE FOR A SYNOPTIC WIND EVENT. ADVISORY CRITERIA SOUTHERLY
WINDS WILL BE POSSIBLE AHEAD OF THE FRONT ACROSS THE HIGHER
TERRAIN...THEN IN THE WAKE OF THE FRONT...THERE WILL BE AN 8 HOUR
PERIOD WHERE SOUTHWEST WINDS WITHIN THE COLD ADVECTION COULD PRODUCE
SFC WIND GUSTS IN EXCESS OF 50 MPH DOWNWIND OF LK ERIE LATE FRIDAY
AFTERNOON AND THE FIRST HALF OF FRIDAY NIGHT. STAY TUNED.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
NOTABLY COOLER WEATHER WILL CHARACTERIZE THIS PERIOD AS SEASONABLY
COOL AIR WILL ACCOMPANY EXPANSIVE HIGH PRESSURE FROM THE NORTHERN
PLAINS.
ON SATURDAY...HIGH PRESSURE WILL GRADUALLY BUILD ACROSS THE UPPER
GREAT LAKES WHILE A DEEP STORM SYSTEM WILL DRIFT TO COASTAL QUEBEC.
THIS WILL KEEP A RELATIVELY TIGHT PRESSURE GRADIENT ACROSS OUR
REGION SO THE STRONG WINDS FROM FRIDAY NIGHT WILL ONLY SLOWLY
SUBSIDE DURING THE COURSE OF SATURDAY. THE GUSTY WINDS AND MUCH
COOLER AIRMASS WILL MAKE FOR A CHILLY DAY AS TEMPS WILL STRUGGLE TO
CLIMB INTO THE MID TO UPPER 40S. THERE COULD ALSO BE A COUPLE
LEFTOVER SHOWERS THROUGH MIDDAY...MAINLY FOR SITES EAST OF
ROCHESTER.
THE EXPANSIVE SFC HIGH WILL BUILD ACROSS OUR REGION SATURDAY NIGHT
AND SUNDAY. THIS WILL PROVIDE US WITH MAINLY CLEAR SKIES FOR THE
SECOND HALF OF THE WEEKEND...ALTHOUGH TEMPERATURES WILL STILL BE
SOME 5 TO 10 DEG F BELOW NORMAL. THE CHILL WILL BE TEMPERED ON
SUNDAY THOUGH WITH AMPLE SUNSHINE.
FOR MONDAY...THE CENTER OF THE SFC HIGH WILL MOVE TO THE CANADIAN
MARITIMES. THE RETURN FLOW AROUND THE HIGH WILL PROMOTE SOME WEAK
WARM ADVECTION OVER THE LOWER GREAT LAKES SO THAT TEMPERATURES WILL
CLIMB BACK TO NEAR NORMAL LEVELS FOR MONDAY.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
THROUGH 15Z...AN INITIAL AREA OF SHOWERS WILL MOVE ACROSS THE
REGION THROUGH 18Z...WITH THIS LIKELY TO LOWER CONDITIONS TO MVFR
IN LOWER CIGS. THE FRONT WILL FOLLOW THIS...POSSIBLY SPARKING
ANOTHER ROUND OF SHOWERS. EXPECT MVFR CONDITIONS TO PERSIST UNTIL
BEHIND THE FRONT WHEN DRIER AIR BUILDS IN THIS EVENING. THERE IS A
CONTINUED CHANCE FOR THUNDERSTORMS THROUGH THIS AFTERNOON...MAINLY
TO THE SOUTH NEAR JHW...HOWEVER AN ISOLATED TSTM CANNOT COMPLETELY
BE RULED OUT AT ANY LOCATION.
DRIER AIR WILL CONTINUE TO BUILD IN OVERNIGHT...WITH VFR
CONDITIONS EXPECTED.
OUTLOOK...
WEDNESDAY...MAINLY VFR.
WEDNESDAY NIGHT AND THURSDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
FRIDAY...DETERIORATION TO MVFR WITH SHOWERS BECOMING LIKELY ALONG
WITH A CHANCE OF THUNDERSTORMS...SOME OF WHICH COULD PRODUCE GUSTY
WINDS.
SATURDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
IN ADVANCE OF A COLD FRONT...SOUTHERLY WINDS TO 15 TO 25 KNOTS
WILL AFFECT EASTERN PORTIONS OF LAKE ERIE AND ONTARIO THIS
MORNING...FOR WHICH SMALL CRAFT ADVISORIES WILL BE IN PLACE.
FOLLOWING THE FRONTAL PASSAGE...WINDS WILL VEER TO WESTERLY AND
DIMINISH THIS AFTERNOON... THEN WILL BECOME RELATIVELY LIGHT FOR
TONIGHT AND WEDNESDAY AS HIGH PRESSURE BRIEFLY NOSES SOUTHEASTWARD
ACROSS THE REGION.
IT SHOULD ALSO BE NOTED THAT WHILE THE FRONT WILL MAINLY JUST
PRODUCE SOME SHOWERS TODAY...A THUNDERSTORM OR TWO WILL ALSO BE
POSSIBLE ACROSS LAKE ERIE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON
FOR LOZ044-045.
&&
$$
SYNOPSIS...JJR
NEAR TERM...APFFEL/JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...APFFEL/JJR
MARINE...APFFEL/JJR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
946 AM EDT TUE APR 16 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TODAY ALONG WITH SOME SHOWERS...
WITH A THUNDERSTORM ALSO POSSIBLE SOUTH OF BUFFALO AND ROCHESTER.
FOLLOWING THE FRONT...SEASONABLY COOLER WEATHER WILL RETURN FOR
TONIGHT AND WEDNESDAY...BEFORE MUCH WARMER AIR SURGES BACK INTO THE
REGION IN TIME FOR THURSDAY ALONG WITH THE CHANCE FOR SOME
ADDITIONAL SHOWERS.
&&
.NEAR TERM /THROUGH TONIGHT/...
DURING THE COURSE OF TODAY...LOW PRESSURE OVER CENTRAL ONTARIO
PROVINCE WILL RAPIDLY EJECT NORTHEASTWARD TO LABRADOR...AND IN THE
PROCESS WILL SLOWLY PUSH ITS TRAILING COLD FRONT SOUTHEASTWARD
ACROSS NEW YORK STATE. AT 900 AM...THIS FRONT WAS LOCATED BETWEEN
LAKE HURON AND LAKE ERIE AND ONTARIO...WITH GOOD MODEL AGREEMENT
THAT THE FRONT WILL MOVE ACROSS WESTERN NEW YORK THIS AFTERNOON.
RADAR SHOWS SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OUT AHEAD OF
THIS FRONTAL BOUNDARY...WITH THE STEADIEST OF THIS TO MOVE INTO
WESTERN PORTIONS OF THE SOUTHERN TIER LATE THIS MORNING. WHILE
SOME OF THE 00Z/06 GUIDANCE STRUGGLED TO FORECAST EXACTLY WHERE
CONVECTION WOULD BREAK OUT...THE LATEST RUNS OF THE HRRR DEPICTS
CURRENT CONDITIONS FAIRLY WELL...AND THUS PROVIDES FAIRLY GOOD
GUIDANCE FOR THE NEXT FEW HOURS. FOLLOWING THIS...EXPECT SHOWERS
TO FILL IN TO THE NORTH LATE THIS MORNING...BRINGING AT LEAST SOME
PRECIPITATION TO NEARLY ALL OF THE REGION THROUGH EARLY AFTERNOON.
HEAVIEST SHOWERS WILL BE SOUTH...WHERE THERE STILL ARE QUITE A FEW
LIGHTNING STRIKES. NAM/GFS MODEL GUIDANCE SHOWS CONTINUED
ELEVATED INSTABILITY IN SOUTHERN SECTIONS...AND THIS IS CONSISTENT
WITH HRRR REFLECTIVITY FORECASTS. THE ONLY QUESTION IS HOW FAR
NORTH WILL THIS MAKE IT...WITH THE HRRR FORECASTING EXPANDING
SHOWER ACTIVITY THIS AFTERNOON ACROSS CENTRAL NEW YORK...LIKELY
DUE TO SOME LIMITED DAYTIME HEATING OUT AHEAD OF THE FRONT. FOR
NOW...KEEP THE MENTION OF THUNDER SOUTH OF I-90. QPFS WILL
VARY...WITH MOST AREAS LIKELY TO SEE A TENTH OF AN INCH OR TWO...WITH
LOCALLY HIGHER AMOUNTS TO A HALF INCH IN THUNDERSTORMS.
OTHERWISE...THE DAY WILL GET OFF TO A WARM AND BREEZY START.
TEMPERATURES WILL REMAIN IN THE 60S AHEAD OF THE RAIN
SHOWERS...WITH HIGHS IN THE UPPER 60S LIKELY IN THE FINGER LAKES
REGION WHERE RAIN WILL HOLD OFF A BIT LONGER.
MEANWHILE...SOUTHERLY WINDS WILL CONTINUE TO GUST TO 30 TO 35 MPH
IN MOST LOCATIONS...WITH GUSTS TO 40 MPH ACROSS HIGHER TERRAIN AND
IN THE BLACK RIVER VALLEY.
LATE THIS AFTERNOON THROUGH TONIGHT...THE FRONTAL BOUNDARY WILL GET
SUPPRESSED FURTHER SOUTH TO THE MASON/DIXON LINE AS HIGH PRESSURE
AND MUCH DRIER AIR BRIEFLY RIDGES SOUTHEAST FROM NORTHERN ONTARIO
PROVINCE. FOR OUR AREA...THIS WILL RESULT IN ANY LINGERING SHOWER
CHANCES ENDING FROM NORTHWEST TO SOUTHEAST LATE THIS AFTERNOON AND
EVENING FOLLOWED BY DRY WEATHER THE REMAINDER OF THE NIGHT...THOUGH
SOME CLOUDS WILL LINGER ACROSS AREAS SOUTH OF LAKE ONTARIO...WHICH
WILL BE CLOSER TO THE SLOWLY DEPARTING FRONTAL ZONE. AS FOR TEMPS...
COOLER AIR FILTERING IN BEHIND THE FRONT WILL RESULT IN TEMPS
FALLING BACK TO THE UPPER 30S TO LOWER 40S SOUTH OF LAKE ONTARIO...
AND TO THE LOWER-MID 30S ACROSS THE NORTH COUNTRY WHERE THERE WILL
BE LESS CLOUD COVER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
A PROGRESSIVE HIGH AMPLITUDE FLOW WILL BE FOUND ACROSS THE UNITED
STATES DURING THIS PERIOD...WITH THE LOWER GREAT LAKES REGION BEING
FORTUNATE ENOUGH TO BE FOUND ON THE WARM SIDE OF AN EXPANSIVE RIDGE.
THIS WILL LEAD TO SEASONABLE CONDITIONS ON WEDNESDAY BEFORE
ANOMALOUS WARMTH RETURNS FOR THURSDAY AND FRIDAY. TEMPERATURES AT
THAT TIME COULD EASILY CLIMB TO MORE THAN 20 DEGREES F ABOVE NORMAL
VALUES. IT IS NOT OUT OF THE QUESTION THAT THE WARMER VALLEYS COULD
EVEN TICKLE THE 80 DEGREE MARK ON THURSDAY.
IN TERMS OF PCPN...THE BULK OF THIS PERIOD WILL BE RAIN-FREE. WHILE
THERE WILL BE THE CHANCE FOR SOME NUISANCE LIGHT SHOWERS AS THE
WARMER AIR WORKS INTO OUR REGION WEDNESDAY NIGHT AND THURSDAY...THE
HIGHEST CHANCE FOR ANY ADVERSE WEATHER WILL COME FRIDAY AFTERNOON
AND NIGHT WHEN A STRONG COLD FRONT WILL PLOW ACROSS THE LOWER GREAT
LAKES. THIS FEATURE COULD END UP GENERATING OUR FIRST WIDESPREAD
SEVERE WEATHER OUTBREAK. SOME DETAILS...
HIGH PRESSURE CENTERED OVER NORTHERN ONTARIO ON WEDNESDAY WILL ARCH
ACROSS THE LOWER GREAT LAKES AND NEW ENGLAND TO PROVIDE US WITH FAIR
SEASONABLE CONDITIONS. THE SUNNIEST CONDITIONS WILL BE FOUND ACROSS
THE EASTERN LAKE ONTARIO REGION WHILE SOME HIGH AND MID LEVEL CLOUDS
CAN BE EXPECTED OVER THE FAR WESTERN COUNTIES. GIVEN THE LIGHT
NORTHERLY FLOW...THE COOLEST WEATHER WILL LIKELY BE FOUND OVER THE
COUNTIES BORDERING THE SOUTH SHORE OF LK ONTARIO WHERE READINGS WILL
STRUGGLE INTO THE LOW 50S. ELSEWHERE...HIGHS SHOULD BE CLOSE TO
THEIR SEASONABLE NORMS OF 55 TO 60.
AS THE LARGE SFC HIGH MOVES EAST ACROSS QUEBEC WEDNESDAY NIGHT...A
DEEP INVERTED TROUGH WILL EXTEND FROM THE CENTRAL PLAINS NORTHEAST
ACROSS THE UPPER GREAT LAKES. A DEEP SOUTHERLY FLOW WILL DEVELOP
BETWEEN THESE SYSTEMS...WITH STRONG WARM ADVECTION FOUND OVER THE
GREAT LAKES REGION. THE LEADING EDGE OF THE WARMER AIRMASS (WARM
FRONT) MAY GENERATE SOME LIGHT SHOWERS/SPRINKLES ACROSS OUR FORECAST
AREA IN THE PROCESS...WITH MORE WIDESPREAD SHRA/TSRA REMAINING OVER
UPPER ONTARIO AND THE UPPER GREAT LAKES.
THE SOUTHERLY FLOW WILL INTENSIFY OVER THE LOWER GREAT LAKES AND
OHIO VALLEY ON THURSDAY AS THE AFOREMENTIONED WARM FRONT WILL LIFT
FROM THE THOUSAND ISLANDS REGION TO SOUTHERN QUEBEC. THIS WILL ALLOW
OUR SKIES TO PARTIALLY CLEAR DURING THE COURSE OF THURSDAY...MUCH
LIKE THEY DID YESTERDAY (MONDAY) WHEN TEMPERATURES REACHED INTO THE
70S. SPEAKING OF WHICH...H85 TEMPS WILL JUMP TO AROUND 14C BY
THURSDAY AFTERNOON AND THIS WILL EASILY SUPPORT DAYTIME HIGHS IN THE
MID 70S WITH 80 DEGREE READINGS NOT OUT OF THE QUESTION IN THE
WARMER VALLEYS.
WARM AND BREEZY CONDITIONS WILL THEN BE FOUND ACROSS THE FORECAST
AREA THURSDAY NIGHT AS DEEPENING LOW PRESSURE WILL LIFT TO LOWER
MICHIGAN WHILE SWEEPING A STRONG COLD FRONT AND ITS ASSOCIATED
SEVERE WEATHER ACROSS THE OHIO AND TENNESSEE VALLEYS. FOR OUR REGION
THOUGH...WE SHOULD BE MAINLY DRY AND QUITE MILD WITH TEMPERATURES
HAVING TROUBLE FALLING BELOW 60. IT WILL BE A LITTLE ON THE HUMID
SIDE AS WELL...MAKING IT FEEL MORE LIKE A NIGHT IN MID-LATE JUNE.
FRIDAY WILL FEATURE VERY UNSETTLED WEATHER AS THE DEEP SFC LOW
TO OUR WEST WILL PUSH ITS STRONG COLD FRONT ACROSS MUCH OF OUR
REGION. FROM THIS VANTAGE POINT...GUIDANCE HAS BEEN CONSISTENT WITH
BRINGING THE FRONT ACROSS WESTERN NEW YORK DURING THE AFTERNOON AND
EVENING. IF THIS TIMING HOLDS UP...TEMPERATURES SHOULD BE ABLE TO
JUMP BACK INTO THE 70S BEFORE THE THICKER CLOUD COVER AND FRONTAL
PCPN MOVES IN. SPEAKING OF WHICH...GIVEN THE STRONG DYNAMICS OF THE
SYNOPTIC SYSTEM AND THE PRESENCE OF A 60-70KT LOW LEVEL JET...WOULD
ANTICIPATE AT LEAST THE THREAT FOR STRONG TO SEVERE THUNDERSTORMS
AHEAD/DURING THE FRONTAL PASSAGE. WHILE GUIDANCE IS NOT DEPICTING
SIGNIFICANT INSTABILITY...CONVECTION COULD EASILY BE SUPPORTED BY
THE STRENGTH OF THE UNDERLYING SYNOPTICS. THE WIND PROFILE AHEAD OF
THE FRONT DEPICTS ALOT OF SHEAR AS WELL...SO THIS IS A VALID
CONCERN. WILL MENTION THIS THREAT IN THE HAZARDOUS WEATHER OUTLOOK.
AS IF THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS IS NOT
ENOUGH...THE STRONG LOW LEVEL JET AND FAVORABLE TRACK OF THE DEEP
SFC LOW FROM LOWER MICHIGAN AND LAKE HURON TO SOUTHERN QUEBEC WILL
SET THE STAGE FOR A SYNOPTIC WIND EVENT. ADVISORY CRITERIA SOUTHERLY
WINDS WILL BE POSSIBLE AHEAD OF THE FRONT ACROSS THE HIGHER
TERRAIN...THEN IN THE WAKE OF THE FRONT...THERE WILL BE AN 8 HOUR
PERIOD WHERE SOUTHWEST WINDS WITHIN THE COLD ADVECTION COULD PRODUCE
SFC WIND GUSTS IN EXCESS OF 50 MPH DOWNWIND OF LK ERIE LATE FRIDAY
AFTERNOON AND THE FIRST HALF OF FRIDAY NIGHT. STAY TUNED.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
NOTABLY COOLER WEATHER WILL CHARACTERIZE THIS PERIOD AS SEASONABLY
COOL AIR WILL ACCOMPANY EXPANSIVE HIGH PRESSURE FROM THE NORTHERN
PLAINS.
ON SATURDAY...HIGH PRESSURE WILL GRADUALLY BUILD ACROSS THE UPPER
GREAT LAKES WHILE A DEEP STORM SYSTEM WILL DRIFT TO COASTAL QUEBEC.
THIS WILL KEEP A RELATIVELY TIGHT PRESSURE GRADIENT ACROSS OUR
REGION SO THE STRONG WINDS FROM FRIDAY NIGHT WILL ONLY SLOWLY
SUBSIDE DURING THE COURSE OF SATURDAY. THE GUSTY WINDS AND MUCH
COOLER AIRMASS WILL MAKE FOR A CHILLY DAY AS TEMPS WILL STRUGGLE TO
CLIMB INTO THE MID TO UPPER 40S. THERE COULD ALSO BE A COUPLE
LEFTOVER SHOWERS THROUGH MIDDAY...MAINLY FOR SITES EAST OF
ROCHESTER.
THE EXPANSIVE SFC HIGH WILL BUILD ACROSS OUR REGION SATURDAY NIGHT
AND SUNDAY. THIS WILL PROVIDE US WITH MAINLY CLEAR SKIES FOR THE
SECOND HALF OF THE WEEKEND...ALTHOUGH TEMPERATURES WILL STILL BE
SOME 5 TO 10 DEG F BELOW NORMAL. THE CHILL WILL BE TEMPERED ON
SUNDAY THOUGH WITH AMPLE SUNSHINE.
FOR MONDAY...THE CENTER OF THE SFC HIGH WILL MOVE TO THE CANADIAN
MARITIMES. THE RETURN FLOW AROUND THE HIGH WILL PROMOTE SOME WEAK
WARM ADVECTION OVER THE LOWER GREAT LAKES SO THAT TEMPERATURES WILL
CLIMB BACK TO NEAR NORMAL LEVELS FOR MONDAY.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
THROUGH 12Z...DRY VFR WEATHER WILL CONTINUE ACROSS THE AREA...ALONG
WITH AN INCREASE IN MID-LEVEL CLOUD COVER IN ADVANCE OF A COLD FRONT
APPROACHING FROM THE CENTRAL GREAT LAKES. LOW LEVEL WIND SHEAR
CONCERNS WILL ALSO PERSIST COURTESY OF A 50 KT SOUTHWESTERLY JET AT
1500 FEET...BEFORE INCREASING MIXING HELPS ALLEVIATE THE LLWS
BETWEEN 12Z AND 14Z THIS MORNING.
AFTER THAT TIME...A COLD FRONT WILL CROSS THE REGION...BRINGING A
PERIOD OF SHOWERS THAT WILL FOCUS ON THE 14Z-19Z TIME FRAME ACROSS
THE FAR WEST...AND 16Z-22Z FURTHER EAST. THESE WILL PROBABLY BRING A
PERIOD OF MVFR CONDITIONS THAT WILL PROBABLY LINGER FOR A FEW HOURS
FOLLOWING THE FROPA...BEFORE DRIER AIR WORKING IN THE CENTRAL GREAT
LAKES BRINGS A RETURN TO VFR CONDITIONS LATER THIS AFTERNOON AND
EARLY THIS EVENING. ONCE ESTABLISHED...THESE VFR CONDITIONS SHOULD
THEN PERSIST THROUGH THE BALANCE OF THE PERIOD.
OUTLOOK...
WEDNESDAY...MAINLY VFR.
WEDNESDAY NIGHT AND THURSDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
FRIDAY...DETERIORATION TO MVFR WITH SHOWERS BECOMING LIKELY ALONG
WITH A CHANCE OF THUNDERSTORMS...SOME OF WHICH COULD PRODUCE GUSTY
WINDS.
SATURDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
IN ADVANCE OF A COLD FRONT...SOUTHERLY WINDS TO 15 TO 25 KNOTS
WILL AFFECT EASTERN PORTIONS OF LAKE ERIE AND ONTARIO THIS
MORNING...FOR WHICH SMALL CRAFT ADVISORIES WILL BE IN PLACE.
FOLLOWING THE FRONTAL PASSAGE...WINDS WILL VEER TO WESTERLY AND
DIMINISH THIS AFTERNOON... THEN WILL BECOME RELATIVELY LIGHT FOR
TONIGHT AND WEDNESDAY AS HIGH PRESSURE BRIEFLY NOSES SOUTHEASTWARD
ACROSS THE REGION.
IT SHOULD ALSO BE NOTED THAT WHILE THE FRONT WILL MAINLY JUST
PRODUCE SOME SHOWERS TODAY...A THUNDERSTORM OR TWO WILL ALSO BE
POSSIBLE ACROSS LAKE ERIE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON
FOR LOZ044-045.
&&
$$
SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...APFFEL/JJR
MARINE...APFFEL/JJR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
913 PM CDT WED APR 17 2013
.UPDATE...
ISSUED AT 902 PM CDT WED APR 17 2013
SNOW BAND LINING UP ACROSS THE FAR SOUTHEAST AND FAR SOUTH CENTRAL
PORTION OF THE STATE FOR THIS EVENING INTO THE EARLY MORNING.
RAISED SNOW TO DEFINITE ACROSS DICKEY...MCINTOSH...AND LAMOURE
COUNTIES AS WELL AS SOUTHEAST EMMONS. VISIBILITIES IN SNOW DOWN TO
3/4 MILE FROM PHILLIP TO MOBRIDGE EARLIER THIS EVENING AND THIS
BAND WILL MOVE NORTHEAST INTO NORTH DAKOTA. RADARS DO SHOW SOME
DECREASE IN COVERAGE/INTENSITY AND THE LATEST RUC IMPLIED THIS
SNOW WILL DIMINISH LATER TONIGHT...SO SNOWFALL IN 2 INCH RANGE
THERE LOOKS OK. REMAINDER OF STATE LOOKS GOOD. CLOUDS MOVING BACK
INTO MINOT...BUT CLEARING NORTHWEST.
UPDATE ISSUED AT 646 PM CDT WED APR 17 2013
CLEARING SKIES POKING INTO THE NORTHWEST AND NORTH CENTRAL THIS
EVENING. BANDS OF HIGH CLOUDS STRETCH SOUTHWEST THROUGH NORTHEAST
AND WILL OVER RUN SOME OF THE CLEARING AREAS SOUTH OF MINOT.
ACROSS THE SOUTHEAST...LIGHT SNOW WILL CONTINUE ACROSS DICKEY...
LAMOURE AND MCINTOSH COUNTIES THROUGH THIS EVENING. MADE SOME
ADJUSTMENTS TO CLOUDS NORTH CENTRAL AND NORTHWEST.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 340 PM CDT WED APR 17 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CONTINUING
CHANCES FOR LIGHT SNOW ACROSS THE SOUTHERN JAMES RIVER VALLEY NOW
THROUGH TONIGHT AND INTO THURSDAY.
CURRENTLY...A DYNAMIC UPPER LEVEL LONG WAVE TROUGH WAS OVER THE
ROCKIES WITH SOUTHWEST FLOW ALOFT OVER THE NORTHERN PLAINS.
MULTIPLE EMBEDDED SHORTWAVES IN THE FLOW WERE MOVING NORTHEAST
FROM THE BASE OF THE TROUGH ACROSS THE SOUTHERN ROCKIES INTO THE
CENTRAL AND NORTHERN PLAINS. AN UPPER LEVEL JET EXTENDS FROM THE
BASE OF THE TROUGH TO CENTRAL SOUTH DAKOTA INTO NORTHERN
MINNESOTA...PROVIDING THE FOCUS AREA FOR A PERSISTENT BAND OF
LIGHT TO MODERATE SNOW OVER MY SOUTHEAST SINCE EARLIER THIS
MORNING TILL NOW. WHILE SOME ACCUMULATIONS ARE OCCURRING...THIS IS
MAINLY ON GRASSY AREAS WITH ROAD SURFACES WET THANKS TO ROAD
SURFACE TEMPERATURES AT 60F OR HIGHER.
DUE IN PART TO OUR RECENT SNOWFALL...HIGH BOUNDARY LAYER MOISTURE
REMAINS ACROSS THE LOCAL REGION RESULTING IN A PERSISTENT STRATUS
DECK STILL IN PLACE OVER MOST OF WEST AND CENTRAL NORTH DAKOTA. DO
NOT SEE THIS DISSIPATING UNTIL MAYBE TOMORROW MORNING/AFTERNOON
WHEN A S/WV RIDGE MOVES INTO THE STATE HELPING TO SCOUR OUT THE
LOW CLOUDS.
WILL CONTINUE WITH THE SPS THROUGH THIS EVENING WITH SOME
ADDITIONAL LIGHT ACCUMULATIONS POSSIBLE SOUTHEAST WITH BOTH THE
NAM AND RAP BRINGING ANOTHER S/WV NORTHEAST ACROSS PORTIONS OF THE
JAMES BASIN THIS EVENING. ALREADY SEE THIS ENHANCED AREA OF
PRECIP EAST OF THE BLACK HILLS AND WEST OF PIERRE ADVECTING
NORTHEAST. WITH NIGHTFALL...ROAD SURFACE TEMPERATURES...AS THEY
DID LAST NIGHT...WILL FALL TO AROUND FREEZING...SO ICY CONDITIONS
ARE POSSIBLE AND WILL MENTION THIS WITHIN THE SPS.
SNOW CHANCES DECREASE THURSDAY MORNING/AFTERNOON ACROSS THE
SOUTHEAST AS THE UPPER JET MIGRATES EAST AND WEAK HIGH PRESSURE
BUILDS IN ACROSS CENTRAL NORTH DAKOTA. WITH THE CLOUDS SCOURING
OUT AND WITH THE S/WV RIDGE PROVIDING SOME WAA...HAVE FORECAST
HIGHS THURSDAY NEAR 40 WEST. 30S CENTRAL AND EAST WITH A MODERATE
NORTH FLOW REMAINING IN PLACE ALONG WITH A LONGER DURATION OF
CLOUDS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 340 PM CDT WED APR 17 2013
NO SIGNIFICANT STORMS IN THE LONG TERM PERIOD...HOWEVER EXPECT AN
ACTIVE PERIOD THROUGH SUNDAY AS PERIODIC CHANCES FOR SNOW/SLEET/RAIN
OCCURS ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THIS WILL RESULT IN
A COUPLE OF INCHES OF MORE SNOW TO ACCUMULATE ESPECIALLY OVER NORTH
CENTRAL NORTH DAKOTA THROUGH SUNDAY. H5 PATTERN FOR MID TO LATE NEXT
WEEK STILL IN GOOD AGREEMENT WITH ESTABLISHING A H5 RIDGE OVER THE
NORTHERN ROCKIES WITH A GRADUAL MODERATING TREND AS DENOTED IN THE
H85 TEMPERATURES ACROSS MONTANA INTO WESTERN AND CENTRAL NORTH
DAKOTA.
BEGINNING THURSDAY NIGHT...A WEAK ALBERTA CLIPPER SYSTEM SLIDES INTO
NORTHWEST NORTH DAKOTA THURSDAY NIGHT AND INTO SOUTH CENTRAL NORTH
DAKOTA 12Z FRIDAY. SHORT RANGE MODELS SHOW A BAND OF LIGHT SNOW OR
POSSIBLY A WINTRY MIX ORIENTED NORTHWEST TO SOUTHEAST WITH UP TO
ONE INCH OF SNOW IN NORTH CENTRAL NORTH DAKOTA...FROM BOWBELLS TO
STANLEY...EAST TO MINOT AND SHERWOOD. PERHAPS A DUSTING COULD OCCUR
ELSEWHERE IN CENTRAL NORTH DAKOTA. LINGERING LIGHT SNOW CONTINUES
INTO FRIDAY MORNING WITH THE LOW EXITING FRIDAY AFTERNOON. EXPECT A
BRIEF PERIOD OF DRY WEATHER FRIDAY AFTERNOON INTO A PORTION OF
FRIDAY NIGHT.
FRIDAY NIGHT/SATURDAY/SUNDAY...SURFACE LOW PRESSURE/WARM FRONT IN
EASTERN MONTANA WILL PROGRESS EAST...RESULTING IN DECENT ISENTROPIC
ASCENT ON THE 285K-295K PRESSURE SURFACES. THIS PRODUCES HIGH
CHC/LIKELY POPS BY LATE FRIDAY NIGHT WEST...AND SPREADING INTO
CENTRAL NORTH DAKOTA SATURDAY. WARMER TEMPERATURES ALOFT WILL RESULT
IN RAIN ACROSS SOUTHWEST NORTH DAKOTA SATURDAY...WITH LIGHT SNOW
ELSEWHERE. WIDESPREAD SNOWFALL ACCUMULATIONS OF UP TO ONE INCH WILL
BE COMMON...WITH A COUPLE OF INCHES FAVORING NORTH CENTRAL NORTH
DAKOTA. ABOVE FREEZING ROAD TEMPERATURES DURING THE DAYLIGHT HOURS
SHOULD ALLOW FOR MELTING...WITH SNOWFALL ACCUMULATIONS MAINLY ON THE
GRASSY AREAS.
FOR MONDAY...A NORTHERN STREAM UPPER LOW/TROUGH FOLLOWS...AND DIGS
INTO WESTERN NORTH DAKOTA WITH A PRECIPITATION THREAT REMAINING
WEST...SOUTH...AND EAST OF THE FORECAST AREA. THIS LOW EJECTS OUT
LATE TUESDAY WITH A BUILDING H5 RIDGE DEVELOPING ALONG THE WEST
COAST. THIS RIDGE SLOWLY SIDES EAST INTO THE NORTHERN ROCKIES
WEDNESDAY THROUGH FRIDAY WITH A GRADUAL WARMUP. ABOVE AVERAGE
TEMPERATURES LIKELY IN THE WEST BY LATE NEXT WEEK. THIS SHOULD ALSO
PROMOTE A GENTLE MELT OF THE SNOWPACK UNDER A DRY WEATHER REGIME.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 902 PM CDT WED APR 17 2013
LARGE LOW PRESSURE EXTENDING FROM IOWA INTO NORTHERN MINNESOTA
WILL SPREAD SNOW TO SOUTHEAST NORTH DAKOTA TONIGHT. HIGH PRESSURE
ACROSS EASTERN MONTANA WILL BEGIN TO CLEAR SKIES ACROSS NORTHWEST
NORTH DAKOTA. MVFR CONDITIONS EXPECTED FROM KDIK-KBIS-KJMS. VFR OR
BECOMING VFR KISN-KMOT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...NH
LONG TERM...KS
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
658 PM CDT WED APR 17 2013
.UPDATE...
ISSUED AT 646 PM CDT WED APR 17 2013
CLEARING SKIES POKING INTO THE NORTHWEST AND NORTH CENTRAL THIS
EVENING. BANDS OF HIGH CLOUDS STRETCH SOUTHWEST THROUGH NORTHEAST
AND WILL OVER RUN SOME OF THE CLEARING AREAS SOUTH OF MINOT.
ACROSS THE SOUTHEAST...LIGHT SNOW WILL CONTINUE ACROSS DICKEY...
LAMOURE AND MCINTOSH COUNTIES THROUGH THIS EVENING. MADE SOME
ADJUSTMENTS TO CLOUDS NORTH CENTRAL AND NORTHWEST.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 340 PM CDT WED APR 17 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CONTINUING
CHANCES FOR LIGHT SNOW ACROSS THE SOUTHERN JAMES RIVER VALLEY NOW
THROUGH TONIGHT AND INTO THURSDAY.
CURRENTLY...A DYNAMIC UPPER LEVEL LONG WAVE TROUGH WAS OVER THE
ROCKIES WITH SOUTHWEST FLOW ALOFT OVER THE NORTHERN PLAINS.
MULTIPLE EMBEDDED SHORTWAVES IN THE FLOW WERE MOVING NORTHEAST
FROM THE BASE OF THE TROUGH ACROSS THE SOUTHERN ROCKIES INTO THE
CENTRAL AND NORTHERN PLAINS. AN UPPER LEVEL JET EXTENDS FROM THE
BASE OF THE TROUGH TO CENTRAL SOUTH DAKOTA INTO NORTHERN
MINNESOTA...PROVIDING THE FOCUS AREA FOR A PERSISTENT BAND OF
LIGHT TO MODERATE SNOW OVER MY SOUTHEAST SINCE EARLIER THIS
MORNING TILL NOW. WHILE SOME ACCUMULATIONS ARE OCCURRING...THIS IS
MAINLY ON GRASSY AREAS WITH ROAD SURFACES WET THANKS TO ROAD
SURFACE TEMPERATURES AT 60F OR HIGHER.
DUE IN PART TO OUR RECENT SNOWFALL...HIGH BOUNDARY LAYER MOISTURE
REMAINS ACROSS THE LOCAL REGION RESULTING IN A PERSISTENT STRATUS
DECK STILL IN PLACE OVER MOST OF WEST AND CENTRAL NORTH DAKOTA. DO
NOT SEE THIS DISSIPATING UNTIL MAYBE TOMORROW MORNING/AFTERNOON
WHEN A S/WV RIDGE MOVES INTO THE STATE HELPING TO SCOUR OUT THE
LOW CLOUDS.
WILL CONTINUE WITH THE SPS THROUGH THIS EVENING WITH SOME
ADDITIONAL LIGHT ACCUMULATIONS POSSIBLE SOUTHEAST WITH BOTH THE
NAM AND RAP BRINGING ANOTHER S/WV NORTHEAST ACROSS PORTIONS OF THE
JAMES BASIN THIS EVENING. ALREADY SEE THIS ENHANCED AREA OF
PRECIP EAST OF THE BLACK HILLS AND WEST OF PIERRE ADVECTING
NORTHEAST. WITH NIGHTFALL...ROAD SURFACE TEMPERATURES...AS THEY
DID LAST NIGHT...WILL FALL TO AROUND FREEZING...SO ICY CONDITIONS
ARE POSSIBLE AND WILL MENTION THIS WITHIN THE SPS.
SNOW CHANCES DECREASE THURSDAY MORNING/AFTERNOON ACROSS THE
SOUTHEAST AS THE UPPER JET MIGRATES EAST AND WEAK HIGH PRESSURE
BUILDS IN ACROSS CENTRAL NORTH DAKOTA. WITH THE CLOUDS SCOURING
OUT AND WITH THE S/WV RIDGE PROVIDING SOME WAA...HAVE FORECAST
HIGHS THURSDAY NEAR 40 WEST. 30S CENTRAL AND EAST WITH A MODERATE
NORTH FLOW REMAINING IN PLACE ALONG WITH A LONGER DURATION OF
CLOUDS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 340 PM CDT WED APR 17 2013
NO SIGNIFICANT STORMS IN THE LONG TERM PERIOD...HOWEVER EXPECT AN
ACTIVE PERIOD THROUGH SUNDAY AS PERIODIC CHANCES FOR SNOW/SLEET/RAIN
OCCURS ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THIS WILL RESULT IN
A COUPLE OF INCHES OF MORE SNOW TO ACCUMULATE ESPECIALLY OVER NORTH
CENTRAL NORTH DAKOTA THROUGH SUNDAY. H5 PATTERN FOR MID TO LATE NEXT
WEEK STILL IN GOOD AGREEMENT WITH ESTABLISHING A H5 RIDGE OVER THE
NORTHERN ROCKIES WITH A GRADUAL MODERATING TREND AS DENOTED IN THE
H85 TEMPERATURES ACROSS MONTANA INTO WESTERN AND CENTRAL NORTH
DAKOTA.
BEGINNING THURSDAY NIGHT...A WEAK ALBERTA CLIPPER SYSTEM SLIDES INTO
NORTHWEST NORTH DAKOTA THURSDAY NIGHT AND INTO SOUTH CENTRAL NORTH
DAKOTA 12Z FRIDAY. SHORT RANGE MODELS SHOW A BAND OF LIGHT SNOW OR
POSSIBLY A WINTRY MIX ORIENTED NORTHWEST TO SOUTHEAST WITH UP TO
ONE INCH OF SNOW IN NORTH CENTRAL NORTH DAKOTA...FROM BOWBELLS TO
STANLEY...EAST TO MINOT AND SHERWOOD. PERHAPS A DUSTING COULD OCCUR
ELSEWHERE IN CENTRAL NORTH DAKOTA. LINGERING LIGHT SNOW CONTINUES
INTO FRIDAY MORNING WITH THE LOW EXITING FRIDAY AFTERNOON. EXPECT A
BRIEF PERIOD OF DRY WEATHER FRIDAY AFTERNOON INTO A PORTION OF
FRIDAY NIGHT.
FRIDAY NIGHT/SATURDAY/SUNDAY...SURFACE LOW PRESSURE/WARM FRONT IN
EASTERN MONTANA WILL PROGRESS EAST...RESULTING IN DECENT ISENTROPIC
ASCENT ON THE 285K-295K PRESSURE SURFACES. THIS PRODUCES HIGH
CHC/LIKELY POPS BY LATE FRIDAY NIGHT WEST...AND SPREADING INTO
CENTRAL NORTH DAKOTA SATURDAY. WARMER TEMPERATURES ALOFT WILL RESULT
IN RAIN ACROSS SOUTHWEST NORTH DAKOTA SATURDAY...WITH LIGHT SNOW
ELSEWHERE. WIDESPREAD SNOWFALL ACCUMULATIONS OF UP TO ONE INCH WILL
BE COMMON...WITH A COUPLE OF INCHES FAVORING NORTH CENTRAL NORTH
DAKOTA. ABOVE FREEZING ROAD TEMPERATURES DURING THE DAYLIGHT HOURS
SHOULD ALLOW FOR MELTING...WITH SNOWFALL ACCUMULATIONS MAINLY ON THE
GRASSY AREAS.
FOR MONDAY...A NORTHERN STREAM UPPER LOW/TROUGH FOLLOWS...AND DIGS
INTO WESTERN NORTH DAKOTA WITH A PRECIPITATION THREAT REMAINING
WEST...SOUTH...AND EAST OF THE FORECAST AREA. THIS LOW EJECTS OUT
LATE TUESDAY WITH A BUILDING H5 RIDGE DEVELOPING ALONG THE WEST
COAST. THIS RIDGE SLOWLY SIDES EAST INTO THE NORTHERN ROCKIES
WEDNESDAY THROUGH FRIDAY WITH A GRADUAL WARMUP. ABOVE AVERAGE
TEMPERATURES LIKELY IN THE WEST BY LATE NEXT WEEK. THIS SHOULD ALSO
PROMOTE A GENTLE MELT OF THE SNOWPACK UNDER A DRY WEATHER REGIME.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 646 PM CDT WED APR 17 2013
LARGE WINTER STORM BRUSHING THE SOUTHEAST PORTION OF NORTH DAKOTA
WEDNESDAY EVENING. EXPECT MVFR CONDITIONS FROM KDIK-KBIS-KJMS
THROUGH 14Z. CONDITIONS BECOMING VFR AFTER 14Z. KISN WILL BE MVFR
WEDNESDAY EVENING...THEN BECOME VFR AFTER 04Z. SOME UNCERTAINTY
ABOUT KMOT. CURRENTLY CLEARING SKIES OVER THE NORTH CENTRAL.
CONCERN THERE MAY BE RETURN TO MVFR AFTER 06Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...NH
LONG TERM...KS
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
804 PM EDT WED APR 17 2013
.SYNOPSIS...
A POTENT SPRING STORM SYSTEM WILL EJECT NORTHEAST THROUGH THE MID
MISSISSIPPI VALLEY TONIGHT THROUGH FRIDAY...BRINGING A WILD SWING
IN TEMPERATURE AND THE THREAT OF STRONG TO SEVERE THUNDERSTORMS.
VERY WARM CONDITIONS ON THURSDAY WITH GUSTY SOUTH WINDS WILL BE
FOLLOWED BY EVEN GUSTIER NORTHWEST WINDS AND TEMPERATURES SOME 30
DEGREES LOWER THAN THAN ON THURSDAY. IN THE WAKE OF THIS
SYSTEM...COOL CANADIAN HIGH PRESSURE WILL SETTLE INTO THE OHIO
VALLEY FOR THE WEEKEND WITH THE THREAT OF MORNING FROST AND SOME
DRY WEATHER.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
KIND OF A TRICKY NEAR TERM FORECAST. SURFACE ANALYSIS/METARS
CLEARLY SHOW A MORE SYNOPTIC SCALE WARM FRONTAL BOUNDARY LIFTING
THROUGH THE I-70 CORRIDOR RIGHT NOW WITH COOL 50S AND EASTERLY
FLOW OVER NRN OHIO/IND...AND SLY FLOW AND MILD 70S OVER SRN
OH/IND. HOWEVER...A PERSISTENT/REMNANT OUTFLOW BOUNDARY CONTINUES
TO PERCOLATE WITH CONVECTION IN A NW-SE AXIS FROM BLOOMINGTON IND
TO LOUISVILLE AND ON TO THE SOUTHEAST FROM THERE. LOCAL LAPS
ANALYSIS SHOWS THAT SURFACE BASED INSTBY HAS LEAKED NORTH OF THE
OUTFLOW BOUNDARY INTO THE TRI STATE AREA...WITH MLCAPES AROUND
1000 J/KG. HOWEVER...FLOW ATOP THE OUTFLOW BOUNDARY IS MODESTLY
WEAK FOR MID APRIL...AND SHEAR IS MARGINAL FOR ORGANIZED STORM
DEVELOPMENT /RIGHT AROUND 30KTS IN THE LOWEST 6KM/ GIVEN THE ALREADY
WEAK INSTBY. LATEST /17.12Z 4KM SPC WRF AND 17.15Z EXPERIMENTAL
3KM HRRR/ RUNS HAVE BEEN TRYING TO SUGGEST THAT ISOLD/SCT UPDRAFTS
WILL SLOWLY MOVE/DEVELOP NORTHEAST TOWARD THE TRI-STATE...MOVING
OFF THE OUTFLOW BOUNDARY BEFORE COLLAPSING SOMEWHERE IN SWRN/WRN
OH OR ERN IND. THIS SEEMS PLAUSIBLE GIVEN THE INSTBY THAT HAS
LEAKED NORTH OF THE OUTFLOW. BACKGROUND ASCENT IS VERY WEAK...THUS
FEEL ANY UPDRAFTS/STORMS WILL BE TIED CLOSELY TO THE DIURNAL
INSTBY CYCLE AND LOCALIZED CONVERGENCE NEAR THE OUTFLOW. HAVE
ALLOWED FOR A 25-30% PROBABILITY OF STORMS IN THE TRI-STATE FOR
THE NEXT 3-4 HOURS BEFORE BACKING OFF INTO LOWER PROBS FURTHER
NORTH AS THE NIGHT WEARS ON. NOT OUT OF THE REALM OF POSSIBILITIES
THAT BRIEF HAIL WOULD BE POSSIBLE WITH THE STRONGER CORES...AND
POCKET OF ELEVATED DCAPE PER SPC MESOA EVEN LENDS SUGGESTION OF A
GUSTY STORM OR TWO. CURRENT TRAJECTORY OF NON-SEVERE CORES
IMMEDIATELY WEST OF KLMK SUGGESTS THAT OWEN/CARROL COUNTIES IN A
FEW HOURS MAY HAVE SOME STRONGER STORMS TO DEAL WITH.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
FOUND MODEL AGREEMENT TO BE VERY STRONG THROUGH THIS PERIOD AND
GOING FORECAST HAD LARGELY CAPTURED THE ENTIRE FCST SCENARIO
EXTREMELY WELL...THUS CHANGES WERE REALLY FOCUSED ON DETAILS OF
WINDS/TIMING OF STORMS...AND TIGHTENING UP GRADIENTS AHEAD/BEHIND
THE EXPECTED COLD FRONT TOMORROW NIGHT.
AFTERNOON GOES WATER VAPOR IMAGERY AND RAP ANALYSIS INDICATED A
VERY DYNAMIC AND COLD LONGWAVE TROUGH /-30C AT 500MB NEAR SLC AT
12Z/ OVER THE INTERMOUNTAIN WEST WITH SEVERAL IMPRESSIVE
CONVECTIVE COMPLEXES DOWNSTREAM NEAR THE ATTENDANT FRONTAL
SYSTEMS OVER THE MID MS VALLEY. HEIGHTS HAVE BEEN RISING OVER THE
OHIO VALLEY MUCH OF THE DAY BUT THAT PROCESS WILL TURN AROUND AS A
STRONG SHORTWAVE TROUGH/UPPER JET DIGS THROUGH THE LONGWAVE TROUGH
AND EJECTS INTO THE CENTRAL PLAINS...LOWERING HEIGHTS DOWNSTREAM
OVER THE OHIO VALLEY AND ALLOWING A STRONG COLD FRONT AND LOW
PRESSURE TO FURTHER ORGANIZE AND PUSH EAST TOWARD THE AREA.
POOL OF VERY WARM /+15C AT H85/ AIR JUST TO OUR SOUTHWEST WILL
LIFT NORTHWARD AS WARM MENTIONED ABOVE CONTINUES NORTH AND DEEPER
SLY FLOW IS ATTAINED. AS DYNAMICS REALLY BEGIN TO INCREASE ON
THURSDAY MORNING...LOW LEVEL WIND FIELD AND FALLING PRESSURES TO
THE WEST WILL INDUCE A POTENT WARM ADVECTION REGIME...WITH
EFFICIENT MIXING UNDER PARTLY CLOUDY SKIES. NAM/GFS SFC PRESSURE
GRADIENT MAGNITUDES AND SOUNDING ANALYSIS VALID THURS AFTN
SUGGESTS A WINDY DAY...SUSTAINED 20 TO 30 MPH WITH GUSTS TO 40
MPH...ESPECIALLY WEST OF I-71 FROM 10 AM THROUGH THE AFTN. A
LITTLE CONCERNED FOR WIND ADVISORY CONDITIONS IN OUR FAR NORTHWEST
WHICH IS A WIND PRONE AREA AND WILL BE UNDER THE STRONGEST
INFLUENCE OF THE DEVELOPING/DEEPENING SFC-850MB CYCLONE AND
ATTENDANT LOW LEVEL JET. WILL CONTINUE TO HIGHLIGHT WIND THREAT ON
HWO. MAX TEMPS SHOULD WARM CONSIDERABLY...INTO THE 80S MOST AREAS
AND WITH A MORE SELY TRAJECTORY OVER OUR EAST...THIS IS
DOWNSLOPE/DRYING OFF THE APPALACHIAN RISE AND MAY ALLOW BETTER
DEW POINT REDUCTION/WARMING. LIKELY WILL FALL A FEW DEGREES SHORT
OF RECORDS...WHICH ARE IN THE MID/UPPER 80S.
GETS VERY INTERESTING THURSDAY AFTER ABOUT 5 PM WHEN STRONG DEEP
LAYERED ASCENT AND LOW LEVEL CONVERGENCE IN VICINITY OF FRONTAL
ZONE TO THE WEST SHOULD CONTINUE TO FOSTER DEVELOPMENT OF A VERY
LONG/STRONG SQUALL LINE. THERE/S BEEN HINTS IN THE HIGHER RES
CONVECTION ALLOWING DATA THAT A FEW DISCRETE CELLS MAY FORM IN THE
WARM SECTOR OVER OUR FAR WEST LATE AFTN/EARLY EVENING AND THAT
WOULD BE PROBLEMATIC GIVEN A WEAK MLCINH FIELD /ERODED CAP/ AND
MLCAPE AROUND 1500 J/KG AMIDST VERY STRONG FLOW /SHEAR/. RIGHT NOW
AM NOT SEEING A STRONG/CONSISTENT SIGNAL THERE...SO KEEPING RAIN
CHANCES LOW THROUGH THE DAY.
AS THE EVENING WEARS ON...ADVANCING FRONTAL ZONE /OR PREFRONTAL
TROUGH/ WILL BECOME FOCUS FOR CONTINUED ADVANCEMENT AND
DEVELOPMENT OF CONVECTIVE SQUALL LINE INTO THE WFO ILN AREA
SOMETIME BETWEEN 10 PM AND 2 AM. THINK LATEST SWODY2 FROM SPC IS
REALISTIC...THAT WFO ILN WRN CWA WILL BE A TRANSITION AREA FROM A
VERY POTENT QLCS WITH SEVERE THREAT...TO A NON-LIGHTNING PRODUCING
LINE OF RAIN OR SHOWERS LATE IN THE NIGHT INTO THE EARLY MORNING HOURS ON
FRIDAY.
CLEARLY THE HIGHEST THREATS LOCALLY OF WIND ARE IN OUR FAR WEST
BEFORE CONVECTION ENTRAINS AN INCREASINGLY HOSTILE LOW LEVEL
AIRMASS /REF ABOVE COMMENT ABOUT DRYING ON SOUTH-SELY FLOW INTO ERN
AREAS/...AND SOUNDING ANALYSIS FROM A MULTITUDE OF NWP SOURCES
INDICATES ANY SURFACE BASED/NEAR SURFACE BASED INSTBY WILL BE
MINIMAL AT BEST /100 J/KG/ WEST OF I-75. PRIOR NOCTURNAL QLCS
EVENTS HOWEVER SUGGEST MLCAPE/MUCAPE IN THESE STRONGLY FORCED
EVENTS IS OVERRATED TO A DEGREE...AND GIVEN THE EXPECTED 0-1KM
SHEAR TOWARD 50KTS...THE SHAPE/ORIENTATION OF THE LOWEST 1KM TEMP
TRACE IS VERY IMPORTANT FOR QLCS COUPLETS AND/OR DAMAGING WIND
TRANSPORT TO THE SURFACE. FCST SOUNDINGS ARE HARD TO BUY INTO
GIVEN FICKLE NATURE OF BOUNDARY LAYER RESOLUTION IN NWP...BUT
ISOTHERMAL TO WEAKLY NEGATIVE LAPSE RATES INDEED SUGGESTS WE MAY
VERY WELL HAVE A THREAT FOR DAMAGING GUSTS ESP IN THE FIRST COUPLE
OF HOURS OF THE EVENT WEST OF I-75. WITH TIME...BUOYANCY REALLY
TANKS AND EXPECT THIS CONVECTIVE SYSTEM TO STRUGGLE TO OR NOT
PRODUCE LIGHTNING OVER THE ERN 1/2 OF THE FORECAST AREA LATE IN
THE NIGHT AND FRIDAY MORNING.
ALSO...WHILE WINDS MAY DECREASE EARLY IN THE EVENING...ISALLOBARIC
COMPONENT IMMEDIATELY IN ADVANCE OF THE VERY SHARP/STRONG FRONAL
ZONE WILL PROBABLY ALLOW FOR A BRIEF/RAPID INCREASE IN SUSTAINED
AND GUSTS IMMEDIATELY AHEAD OF THE SQUALL LINE.
FOR FLOOD CONCERN...SYSTEM WILL BE PROGRESSIVE AND HAVE HIGH
CONFIDENCE IN RAIN AMOUNTS REMAINING LESS THAN AN INCH IN MOST
AREAS. HEAVIEST WEST...LIGHTEST EAST. FEEL ANY FLOODING ISSUES
WOULD BE BRIEF/NUISANCE AND TIED TO AREAS OF VERY MOIST SOILS FROM
MERCER INTO HARDIN/DELAWARE COUNTIES.
FRIDAY TO BE POLAR OPPOSITE OF THURSDAY...A 30 DEGREE TEMP CHANGE
/PERHAPS MORE IN THE WEST/ FROM DAYTIME MAX TO DAYTIME MAX...WITH
MORE GUSTY WINDS AND A RAPID END TO THE RAIN WITH DRY SLOT. THINK
WIND ADVISORY MAY BECOME LIKELY IN NORTH/WEST AT SOME POINT AS SFC
CYCLONE REACHES LOWEST PRESSURES /SUB-990MB/ OVER LAKE SUPERIOR. A
VERY CHILLY/MISERABLE DAY IN COMPARISON TO THURSDAY.
ENOUGH WEAKENING IN THE MSLP GRADIENT FRIDAY NIGHT AND POTENTIAL
CLEARING TO WARRANT INSERT OF PATCHY FROST...THOUGH FOLLOWING
NIGHT LOOKS EVEN BETTER FOR FROST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A STRONG AREA OF HIGH PRESSURE WILL BUILD IN THE MID SECTION OF THE
COUNTRY ON SATURDAY AND NOSE INTO THE GREAT LAKES AND OHIO VALLEY
REGION BY EVENING. SOUTHEAST FLOW WILL THEN GRADUALLY TURN SOUTH
AHEAD OF THE NEXT COLD FRONT EXPECTED TO MOVE THROUGH LATE IN THE
FORECAST PERIOD.
MODELS ARE IN A WIDE RANGE FOR TIMING FOR THE TUESDAY/WEDNESDAY
SYSTEM. THE PREVIOUS FORECAST APPEARS TO HAVE THE BEST INITIAL
CONDITIONS BUT SOME NEIGHBORING OFFICES APPEAR HIGHER THAN I AM
WILLING TO GO WITH RAIN CHANCES OVERNIGHT TUESDAY. GIVEN THE LATEST
EUROPEAN WHICH SPINS THE SYSTEM UP IN THE MIDWEST ON TUESDAY...IT
HAS A MUCH SLOWER AND MORE DEVELOPED SYSTEM THAN THE GFS WHICH IS
INDICATING AN OPEN WAVE YET STRONG COLD FRONTAL PASSAGE EARLY
WEDNESDAY. WPC HAS THIS FRONT ON THE OTHER SIDE OF THE APPALACHIANS
AT THIS TIME WHICH APPEARS INCONSISTENT WITH THE REST OF THE
GUIDANCE I SEE.
UNTIL THE RAIN HITS WITH THE NEXT SYSTEM DAYS 6/7...TEMPERATURES
WILL BE ON THE INCREASE AND START FROM A COOLER 50S ON SATURDAY WITH
OVERNIGHT LOWS LIKELY NEEDING FROST HEADLINES. BY THIS TIME NEXT
WEEK AHEAD OF THE COLD FRONT...70S WILL BE FOUND AGAIN WITH
OVERNIGHT LOWS IN THE 50S. HAVE GONE WARMER THAN GUIDANCE AHEAD OF
THE NEXT SYSTEM BUT FEEL THAT THE FORECAST WILL CONTINUE TO BE
ADJUSTED UPWARD A LITTLE BIT EACH DAY.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
A WARM FRONT SITUATED ACROSS THE TAF SITES WILL CONTINUE TO PUSH NORTH
TONIGHT. WINDS WILL GRADUALLY BECOME MORE SOUTHERLY ACROSS THE TAF
SITES. GUIDANCE IS SUGGESTING SOME MVFR FOG AT THE TAF SITES
OVERNIGHT HOWEVER BELIEVE WITH WINDS STAYING UP THROUGH THE NIGHT
THAT FOG WILL PROBABLY NOT BE AN ISSUE. WINDS WILL REALLY RAMP UP
FOR THE DAY ON THURSDAY WITH WIND GUSTS EXCEEDING 30 KNOTS AT
TIMES FOR THE LATE MORNING AND THROUGH THE AFTERNOON HOURS.
ALTHOUGH A FEW SPOTTY SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
DURING THE DAY ON THURSDAY COVERAGE WILL BE VERY LIMITED AND
THEREFORE LEFT OUT OF THE TAFS AT THIS TIME.
OUTLOOK...GUSTY SOUTHERLY WINDS WILL CONTINUE THROUGH THURSDAY EVENING.
A BRIEF PERIOD OF MVFR CEILINGS AND VISIBILITIES ARE POSSIBLE AS
SHOWERS AND THUNDERSTORMS MOVE THROUGH LATE THURSDAY NIGHT AND
EARLY FRIDAY MORNING. WEST WINDS GUSTING TO 30 KT LIKELY FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BINAU
NEAR TERM...BINAU
SHORT TERM...BINAU
LONG TERM...FRANKS
AVIATION...NOVAK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
849 AM EDT TUE APR 16 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE SOUTH ACROSS THE AREA TODAY AND STALL
ACROSS SOUTHERN OHIO TONIGHT. THIS FRONT WILL LIFT NORTH AS A WARM
FRONT ON WEDNESDAY NIGHT AHEAD OF A LOW PRESSURE SYSTEM APPROACHING
FROM THE PLAINS. THIS SYSTEM WILL TRACK NORTHEAST THROUGH THE GREAT
LAKES REGION PULLING A STRONG COLD FRONT EAST ACROSS THE AREA ON
FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED...MINOR ADJUSTMENT TO POP AND WX GRIDS BASED ON RADAR THIS
MORNING AND EXPECTED MOVEMENT THROUGH THE MORNING AND EARLY
AFTERNOON. ALSO ADJUSTED HOURLY TEMPS AND AFTERNOON HIGH TEMP
USING HRRR GUIDANCE WHICH SHOWS NICELY THE COOL DOWN OFF THE LAKE
THIS AFTERNOON AS WINDS TURN ONSHORE.
ORIGINAL DISCUSSION...APPROACHING FRONTAL BOUNDARY IS STILL
LOCATED ACROSS SE LOWER MICHIGAN EARLY THIS MORNING. CONVECTION
HAS BEEN RAPIDLY APPROACHING ACROSS CENTRAL ILLINOIS AND WESTERN
INDIANA WHERE DEEP MOISTURE CONVERGENCE IS MAXIMIZED ALONG THE
925-850MB FRONT. WE WILL CONTINUE TO SEE MOISTURE ADVECTION
INCREASING ACROSS NRN OHIO WHERE THE LOW LEVEL JET IS FOCUSED WITH
CONVERGENCE INCREASING AS THE FRONT SETTLES SOUTH. EXPECTING TO
SEE SHOWERS AND THUNDERSTORMS SPREAD EAST ACROSS NRN OHIO...EVEN
REACHING NW PA BY LATE THIS MORNING. OVERALL COVERAGE OF SHOWERS
WILL DECREASE BY THIS AFTERNOON AS WE LOSE THE LOW LEVEL JET
SUPPORT AND MORE STABLE AIR ARRIVES BEHIND THE FRONT. TEMPERATURES
WILL FALL AS THE RAIN MOVES IN THIS MORNING AND WILL STRUGGLE TO
RECOVER BEHIND THE FRONT THIS AFTERNOON. HIGHS WILL RANGE FROM THE
UPPER 50S TO LOW 60S SOUTH.
CHALLENGE FOR THIS AFTERNOON WILL BE DETERMINING COVERAGE OF SHOWERS
AND THUNDERSTORMS AS THE FRONT SINKS SOUTH WHILE MAIN UPPER LEVEL
SUPPORT PASSES WELL NORTH OF THE AREA. MODEL SOUNDING ARE A BIT
OVERDONE WITH DEWPOINTS BY THIS AFTERNOON AND THINK WE WILL SEE
VALUES ACROSS CENTRAL OHIO PEAK IN THE LOWER 50S WHICH WILL LIMIT
SURFACE BASED INSTABILITY. WE WILL HAVE TO KEEP AN EYE ON WHERE THE
FRONTAL BOUNDARY SETS UP BUT EXPECTING BEST CHANCES WILL BE ACROSS
THE EXTREME SE PORTION OF THE FORECAST AREA FROM MOUNT VERNON TO
YOUNGSTOWN ALONG AND BEHIND THE FRONT. A LITTLE HARD TO PINPOINT IF
THERE WILL BE ENOUGH SHORTWAVE ENERGY RIDING AROUND THE RIDGE LATE
THIS AFTERNOON TO FIRE OFF A SECOND ROUND OF CONVECTION BUT WILL
HOLD ONTO CHANCE POPS TO ACCOUNT FOR THIS. SPC KEEP THE SLIGHT RISK
FOR SEVERE THUNDERSTORMS JUST TO OUR SOUTH AND AGREE WITH THE
LOCATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
UPPER LEVEL RIDGE BUILDS AGAIN OVERNIGHT AS THE WESTERN TROUGH
PUSHES EASTWARD. THE NAM HAS BEEN THE MORE ENERGETIC MODEL WITH
ISENTROPIC ASCENT INCREASING ACROSS NW OHIO AND TRIES TO SHOW
SHOWERS DEVELOPING. THINK THIS IS OVERDONE WITH BETTER LIFT
ASSOCIATED WITH THE LLJ FOCUSED BACK TOWARDS IOWA SO WILL ONLY
CARRY LOW POPS IN THE WEST OVERNIGHT. THE WARM FRONT LOOKS SLOW TO
LIFT BACK NORTH ON WEDNESDAY WITH MOSTLY CLOUDY SKIES IN PLACE
ACROSS THE AREA. EAST TO NORTHEAST FLOW OFF THE LAKE WILL KEEP
TEMPERATURES AT OR BELOW NORMAL IN THE UPPER 50S TO NEAR 60
DEGREES.
WARM FRONT PUSHES BACK NORTH WEDNESDAY NIGHT LEAVING THE FORECAST
AREA IN THE WARM SECTOR ON THURSDAY. BREEZY SOUTHERLY WINDS NEAR 20
MPH WITH GUSTS OF 30-35 MPH ARE POSSIBLE WHICH WILL HELP TO PUSH
TEMPERATURES NEAR THE 80 DEGREE MARK. THE FRONT WILL BE CLOSE ENOUGH
TO NW OHIO TO SEE OCCASIONAL SHOWERS/THUNDERSTORMS AND ENOUGH CLOUDS
TO KEEP TEMPERATURES A FEW DEGREES COOLER. OTHERWISE THE FRONT
FINALLY SWEEPS EAST ACROSS THE AREA ON FRIDAY BRINGING A RETURN
TO MUCH COOLER TEMPERATURES FOR THE WEEKEND. MODELS HAVE BEEN
SLOWING DOWN THE TIMING OF THE FRONT BUT CURRENTLY SHOW IT
CLEARING MOST OF THE AREA BY MID AFTERNOON ON FRIDAY. ANY FURTHER
SLOWING WILL HELP TO INCREASE INSTABILITY AND POTENTIAL FOR STRONGER
THUNDERSTORMS ALONG THE FRONT.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
THE UPPER LEVEL TROUGH SHOULD MOVE EAST OF THE REGION ON SATURDAY.
HOWEVER THERE MAY STILL BE SOME LINGERING RAIN OR SNOW SHOWERS
ACROSS NW PA THROUGH SATURDAY MORNING. HIGH PRESSURE IS EXPECTED TO
TAKE CONTROL BY SATURDAY NIGHT BUT WILL MOVE OFF THE NEW ENGLAND
COAST BY MONDAY MORNING. AFTER A COLD DAY WITH HIGHS IN THE 40S ON
SATURDAY IT WILL BE WARMER ON SUNDAY...BUT STILL BELOW SEASONAL
AVERAGES. AS SOUTHERLY WINDS RETURN ON MONDAY HIGHS WILL RETURN TO
WITHIN A COUPLE DEGREES OF 60.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
OUTFLOW FROM SHOWERS AND THUNDERSTORMS ACROSS NW OHIO ARE HELPING
MOVE A COLD FRONT INTO THE CENTRAL PORTION OF NORTHERN OHIO. THERE
HAS BEEN SOME MVFR CONDITIONS WITH LOCALIZED IFR IN THE HEAVIEST
THUNDERSTORMS. THE BETTER CHANCES OF SEEING THUNDER THIS MORNING
WILL BE GENERALLY ALONG AND NORTH OF A KFDY TO KCLE TO KERI LINE.
MOST OF THE MORNING THUNDERSTORMS SHOULD WEAKEN AS THEY LIFT TO
THE NORTHEAST. AWAY FROM THESE MORNING SHOWERS AND THUNDERSTORMS
MOST LOCATIONS WILL BE VFR.
UNCERTAINTY FOR THE AFTERNOON IS HOW MUCH SHOWER AND THUNDERSTORM
ACTIVITY WILL DEVELOP ALONG THE FRONTAL BOUNDARY THAT SHOULD BE
NEAR A KJHW TO KI43 LINE AROUND 20Z. BELIEVE THE THUNDER CHANCES
ARE HIGH ENOUGH TO MENTION AT KCAK AND KYNG FOR THE MID TO LATE
AFTERNOON. THE SHOWERS AND THUNDERSTORMS THAT CAN DEVELOP WILL
PRODUCE MVFR CONDITIONS. AWAY FROM THE SHOWERS CEILINGS SHOULD BE
VFR.
WINDS WILL REMAIN GUSTY AHEAD OF THE FRONT FROM A SOUTHERLY
DIRECTION BUT WILL SHIFT AROUND TO THE WEST AND NORTHWEST THROUGH
THE AFTERNOON. WINDS WILL EVENTUALLY MAKE IT AROUND TO THE
NORTHEAST DURING THE EVENING.
.OUTLOOK...NON VFR AT TIMES IN SHOWERS AND THUNDERSTORMS TUESDAY NIGHT
INTO WEDNESDAY AND AGAIN ON FRIDAY.
&&
.MARINE...
SOUTHERLY WINDS WILL BE STRONGEST THIS MORNING ALONG THE PA
SHORELINE. BELIEVE WE WILL REMAIN JUST UNDER SMALL CRAFT CONDITIONS.
WINDS WILL SHIFT LATE THIS MORNING TO EARLY AFTERNOON AS A COLD
FRONT MOVES ACROSS THE LAKE. THIS FRONT WILL STALL NEAR THE OHIO
RIVER VALLEY THEN MOVE BACK TO THE NORTH AS A WARM FRONT. THE WARM
FRONT WILL LIFT NORTH OF LAKE ERIE WEDNESDAY WITH SOUTHERLY WINDS
RETURNING. SOUTHERLY WINDS MAY END UP BEING STRONG ENOUGH AHEAD OF
ANOTHER COLD FRONT ON FRIDAY TO CAUSE SMALL CRAFT ADVISORY
CONDITIONS. COLD ADVECTION IN THE WAKE OF THIS FRONT WILL BE STRONG
ENOUGH TO INCREASE SOUTHWESTERLY WINDS TO 30 KNOTS. WE WILL NEED TO
MONITOR FOR THE POTENTIAL OF GALE CONDITIONS FOR A FEW HOURS FRIDAY
NIGHT INTO EARLY SATURDAY. HIGH PRESSURE WILL TAKE CONTROL BY
SATURDAY NIGHT WITH CALMER CONDITIONS EXPECTED.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC/TK
SHORT TERM...KEC
LONG TERM...MULLEN
AVIATION...MULLEN
MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
848 PM CDT WED APR 17 2013
.UPDATE...
ISSUED AT 845 PM CDT WED APR 17 2013
FIRST WAVE EXITING CWA THIS EVENING WITH A LULL IN THE
PRECIPITATION. HRRR IS HANDLING THIS FEATURE QUITE WELL WITH
SECONDARY WAVE LIFTING NORTHEAST INTO CWA AFTER 06Z TONIGHT. MORE
CONVECTION IS FIRING UP ACROSS KANSAS WITH THIS FEATURE WHICH
AGAIN FORECAST FAIRLY WELL BY HRRR. SO WILL HAVE LOWERED POPS THE
REST OF THE EVENING WITH AN INCREASE IN POPS AGAIN LATER TONIGHT.
NO CHANGE IN HIGHLIGHTS EXPECTED.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 314 PM CDT WED APR 17 2013
IN THE SHORT RANGE...FORECAST AREA IS BETWEEN WAVE SEGMENTS...WITH
THE WARM AIR ADVECTION FROM THIS MORNING GONE...AND THE MAIN PORTION
OF THE UPPER TROUGH/WAVE ENERGY STILL TO THE SOUTH. CURRENTLY...NEXT
ROUND OF CONVECTION IS NOW FIRING UP IN CENTRAL KANSAS...WHICH MAY
SCRAPE ALONG OUR SOUTHEAST ZONES THIS EVENING. THEREFORE KEPT THE
MENTION OF RAIN WITH EMBEDDED THUNDER IN THOSE AREAS THIS EVENING.
BUT ELSEWHERE...DRY MID LEVELS WILL INHIBIT BONAFIDE PRECIPITATION
FROM FALLING. RELIED HEAVILY ON THE WARMEST MODEL ALOFT I COULD
FIND...WITH WAS THE NAM FOR PRECIPITATION TYPE. BUT OVERALL FOR
THIS EVENING OUTSIDE OF NORTHWEST IOWA...JUST WENT OCCASIONAL LIGHT
PRECIPITATION WITH THE TYPE DEPENDING ON WHAT THE SURFACE
TEMPERATURES AND THE WARM AIR BUBBLE ALOFT WERE DOING. LATER
TONIGHT...THE MAIN PORTION OF THE WAVE BEGINS TO ENCROACH INTO OUR
AREA THEREFORE EXPECTING THE MID LEVELS TO SATURATE.
THEN ON THURSDAY...PV ADVECTION IS VERY STRONG AS THE WAVE STRONGLY
INFLUENCES THIS REGION. THE UPPER QG FORCING MOVES RIGHT OVER THE
HEART OF OUR FORECAST AREA...AND MID LEVEL INSTABILITY IS EVIDENT.
LASTLY...A DECENT TROWAL EXISTS AT THE 305K LEVEL INTO OUR FORECAST
AREA BACKING INTO SW MN...EAST CENTRAL SD AND SOUTHEAST SD. WITH ALL
THIS SAID...THERE COULD VERY WELL BE A HEAVY BAND OF SNOW SETTING UP
LATE TONIGHT AND THURSDAY IN THESE LOCATIONS AND IMMEDIATE ADJACENT
AREAS FOR 6 TO 9 INCHES OF SNOW...COUPLED WITH A LOT OF WIND OF 25
TO 35 MPH...AND SOME GUSTS UP TO 40 MPH. THEREFORE DECIDED TO ISSUE
A WINTER STORM WARNING FOR THOSE AREAS. ELSEWHERE...DECIDED TO ISSUE
AN ADVISORY FOR LATE TONIGHT THROUGH THURSDAY EVENING EXTENDING
EASTWARD INCLUDING A LINE FROM SIOUX CITY...TO SPENCER IOWA AND
JACKSON MN...FOR THE POTENTIAL OF SOME LIGHT ICING LATE TONIGHT
FOLLOWED BY 2 TO 4 INCHES OF SNOW AND THE WIND. THE CURRENT WINTER
WEATHER ADVISORY IN OUR WESTERN ZONES STILL LOOKED GOOD...AS LESS
POTENTIAL FOR HEAVY SNOW EXISTS IN THOSE ZONES.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 314 PM CDT WED APR 17 2013
RELATIVELY GOOD MODEL AGREEMENT IN THE NEAR TERM WITH TROWAL WORKING
THROUGH THE AREA THURSDAY NIGHT. HAVE INCREASED POPS WITH THIS
FEATURE...ESPECIALLY EAST OF THE JAMES RIVER VALLEY. SYSTEM PULLS
OUT OF THE AREA ON FRIDAY..HOWEVER...BRISK NORTHWEST WINDS CONTINUE
THROUGHOUT THE DAY. MODELS INDICATE RELATIVELY POOR MIXING WITH
MID CLOUD AND FRESH SNOW COVER ACROSS THE AREA...SO GUSTS MAY NOT BE
AS BAD AS THEY WOULD BE WITHOUT THESE FEATURES.
APPEARS AS THOUGH SKIES WILL CLEAR FRIDAY NIGHT...AND WITH WINDS
DROPPING OFF SHOULD SEE GREAT RADIATIVE CONDITIONS. MID LEVEL
CLOUDS WILL BE ON THE INCREASE ACROSS CENTRAL SOUTH DAKOTA AFTER
MIDNIGHT IN ADVANCE OF THE NEXT SERIES OF WAVES APPROACHING THE
AREA. AS A RESULT...HAVE COOLEST TEMPERATURES FORECAST FROM I-29
AND EAST ALONG THE HIGHWAY 14 CORRIDOR.
DIRTY ZONAL FLOW DOMINATES ACROSS THE REGION THROUGH THE WEEKEND
INTO EARLY NEXT WEEK. HAVE THE CHANCE OF SHOWERS WITH THESE
DISTURBANCES MOVING THROUGH...HOWEVER...AS A SURFACE COLD FRONT
MOVES SOUTH THROUGH THE AREA SUNDAY NIGHT INTO MONDAY LOWER LEVELS
COOL OFF ENOUGH THAT PREVAILING PRECIPITATION TYPE COULD SWITCH AND
CHANGE OVER TO SNOW.
MODELS DISSENSION INCREASES TOWARDS THE MIDDLE OF NEXT WEEK AS
ECMWF SUGGESTS A DEEPENING TROUGH ON THE BACK EDGE OF THE SHORT
WAVE TRAIN...WHILE THE GFS ADVERTISES MORE OF A FULL LATITUDINAL
TROUGH. WITH UNCERTAINTY WITH THE SYSTEM...LEFT MID-RANGE POPS IN
THROUGH TUESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 629 PM CDT WED APR 17 2013
DETERIORATING CONDITIONS THROUGH THE NIGHT AS MIXED PRECIPITATION
OVERSPREADS THE AREA. MAY HAVE SOME ISOLATED THUNDERSTORM ACTIVITY
OVER NORTHWESTERN IOWA EARLY IN THE EVENING...OTHERWISE
PRECIPITATION THAT DEVELOPS WILL BE MAINLY IN THE FORM OF SNOW
THROUGH THE JAMES RIVER VALLEY...WITH A BAND OF MIXED
PRECIPITATION EAST OF THIS AREA...THEN ALL RAIN THROUGH
NORTHWESTERN IOWA. AS THE NIGHT PROGRESSES...PRECIPITATION WILL
TRANSITION TO ALL SNOW FROM WEST TO EAST...WITH SNOW THEN
PERSISTING INTO THURSDAY EVENING. IN ADDITION...NORTHWESTERLY
WINDS WILL INCREASE TONIGHT AND TOMORROW...WITH GUSTS OF 35 TO 40
KTS ON THURSDAY AFTERNOON.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 1 AM THURSDAY TO 1 AM CDT FRIDAY
FOR SDZ070-071.
WINTER STORM WARNING UNTIL 1 AM CDT FRIDAY FOR SDZ039-040-054-
055-060-061-065-068.
WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR SDZ038-050-052-
053-057>059-063-064.
WINTER STORM WARNING FROM 1 AM THURSDAY TO 1 AM CDT FRIDAY FOR
SDZ056-062-066-067-069.
MN...WINTER WEATHER ADVISORY FROM 1 AM THURSDAY TO 1 AM CDT FRIDAY
FOR MNZ090.
WINTER STORM WARNING FROM 1 AM THURSDAY TO 1 AM CDT FRIDAY FOR
MNZ071-072-080-081-089-097-098.
IA...WINTER WEATHER ADVISORY FROM 1 AM THURSDAY TO 1 AM CDT FRIDAY
FOR IAZ002-012-020.
WINTER STORM WARNING FROM 1 AM THURSDAY TO 1 AM CDT FRIDAY FOR
IAZ001.
WINTER WEATHER ADVISORY FROM 4 AM THURSDAY TO 1 AM CDT FRIDAY
FOR IAZ003-013-014-021-031.
NE...WINTER WEATHER ADVISORY FROM 1 AM THURSDAY TO 1 AM CDT FRIDAY
FOR NEZ013.
WINTER WEATHER ADVISORY FROM 4 AM THURSDAY TO 1 AM CDT FRIDAY
FOR NEZ014.
&&
$$
UPDATE...
SHORT TERM...MJF
LONG TERM...
AVIATION...JM
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
509 PM MDT WED APR 17 2013
.UPDATE...
ISSUED AT 502 PM MDT WED APR 17 2013
LATEST WATER VAPOUR LOOP AND 21Z RAP GUIDANCE SHOW NEXT WAVE OVER
NM...HEADING SWIFTLY TO THE NORTHEAST ON NOSE OF 130KT JET. LIFT
ON NOSE OF THIS JET STREAK AND EXITING JET STREAK OVER THE UPPER
MIDWEST WILL COMBINE TO BRING INCREASING AREAS OF -SN OVER
NE PER KLNX RADAR...WHICH WILL HEAD INTO SOUTH CENTRAL SD TONIGHT.
EXPECT MAIN ACCUMULATING SNOWS TO BE OVER THESE AREAS OVERNIGHT.
FURTHER WEST -SN WILL LINGER...BUT ACCUMULATIONS WILL BE LIGHT.
WILL THUS SHAVE OFF ALL HEADLINES SAVE FOR SOUTH CENTRAL SD WHERE
SEVERAL MORE INCHES OF SNOW ARE EXPECTED OVERNIGHT.
&&
.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 238 PM MDT WED APR 17 2013
CURRENT SURFACE ANALYSIS PLACES LOW OVER NORTHERN NEW MEXICO WITH
HIGH SETTLING INTO THE NORTHERN ROCKIES. UPPER LEVEL ANALYSIS
PLACES DEEP TROF OVER THE WRN INTO THE CTRL CONUS WITH AXIS
STRETCHING FROM ERN SASKATCHEWAN SOUTHWARD TOWARDS THE FOUR
CORNERS REGION...WITH BASE CLOSING OFF NEAR WRN COLORADO. VARIETY
OF WAVES CONTINUE TO PUSH UP ALONG THE FRONT OF THE WAVE. MAIN
AREA OF SNOW OVER PTNS OF SW INTO S CTRL SD ORIENTATED ALONG AXIS
OF INCREASING 700 MB FRONTOGENESIS...WHILE OTHER SMALLER BANDS
CONTINUE OVER THE CWA.
FOR TONIGHT...UPPER TROF CONTINUES ITS SLOW PUSH TO THE EAST WITH
SNOW SLOWLY TAPERING FROM WEST TO EAST THROUGH THE OVERNIGHT OVER
NERN WYO INTO WRN SD. OVER S CTRL SD...PRIMARY BAND OF SNOW SHIFTS
OVER THE AREA THIS EVENING. LATE TONIGHT PRIMARY WAVE WRAPPING
AROUND CLOSED LOW EJECTING INTO THE PLAINS WILL PASS MAINLY TO THE
EAST...THOUGH ENOUGH LIFT WITH THIS SHOULD KEEP SNOWFALL GOING
INTO THE MORNING HOURS.
ON THURSDAY...SOME SNOW WILL LINGER INTO THE MORNING HOURS OVER S
CTRL SD BEFORE SLOWLY ENDING INTO THE AFTERNOON AS UPPER LOW
SLOWLY WORKS ITS WAY TO THE EAST. OVER REMAINDER OF THE CWA...DRY
CONDITIONS ARE EXPECTED AS RIDGING QUICKLY BUILDS IN. SFC LOW
EJECTS THRU THE MIDWEST AND DEEPENS BRINGING INCREASING NRNLY
WINDS TO THE ERN CWA...WHICH MAY LEAD TO SOME BLOWING SNOW.
&&
.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 238 PM MDT WED APR 17 2013
MOSTLY DRY CONDITIONS ARE EXPECTED FRIDAY AS A SHORT WAVE RIDGE
CROSSES THE NORTHERN PLAINS. AN UPPER TROF WILL SET UP ACROSS THE
NORTHERN PLAINS FOR THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL
BRING PERIODIC CHANCES FOR RAIN/SNOW ALONG WITH TEMPERATURES
REMAINING BELOW AVERAGE. AN UPPER LEVEL RIDGE WILL START TO MOVE
INTO THE NORTHERN PLAINS AROUND MIDWEEK...BRINGING DRY CONDITIONS
AND MORE SEASONABLE TEMPERATURES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 502 PM MDT WED APR 17 2013
WIDESPREAD IFR/MVFR CONDITIONS DUE TO LOW CLOUDS/-SN EXPECTED TONIGHT
INTO EARLY THURSDAY MORNING ACROSS MUCH WESTERN SD. CONDITIONS
WILL BEGIN TO SLOWLY IMPROVE ACROSS NORTHEAST WYOMING LATER THIS
EVENING AND OVERNIGHT AS SNOW TAPERS OFF AND CEILINGS RISE TO MVFR
LEVELS. CONDITIONS WILL THEN IMPROVE THURSDAY AS STORM SYSTEM
MOVES TO THE EAST.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM MDT THURSDAY FOR SDZ043-044.
WINTER WEATHER ADVISORY UNTIL NOON CDT THURSDAY FOR SDZ046-047-
049.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...77
LONG TERM...15
AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
340 PM CDT TUE APR 16 2013
.SHORT TERM...
FRONTAL BOUNDARY HAS SAGGED SOUTH THROUGH THE INTERSTATE 20 CORRIDOR
THIS AFTERNOON...WITH NORTH WINDS AT SWEETWATER AND BRIEFLY AT
ABILENE. LOOKS LIKE THE FRONT HAS PULLED UP STATIONARY OR MAYBE
DRIFTING WEST...WITH MODELS SUGGESTING A RETREAT NORTHWARD AS A WARM
FRONT THIS EVENING. HOW FAR NORTH IT RETREATS IS A HUGE
QUESTION...WITH THE GFS SHOWING A RAPID RETREAT AND THE RUC MUCH
SLOWER. AT THIS POINT...WITH THE GFS HAVING LARGELY MISSED HOW FAR
SOUTH THE FRONT WOULD MAKE IT TODAY...AND WITH TEMPERATURES IN THE
50S AND STILL GOOD NORTHEAST FLOW ACROSS OKLAHOMA...WILL LEAN
TOWARDS A SOMEWHAT SLOWER RETREAT.
VISIBLE SATELLITE SHOWING A LITTLE CU TRYING TO GO ALONG AND JUST
NORTH OF THE FRONT ACROSS THE BIG COUNTRY. CAP IS STILL STRONG...BUT
AT LEAST A FEW STORMS LOOK VERY POSSIBLE...AS THE CAP WEAKENS
LOCALLY AND AS A WEAK UPPER LEVEL SHORTWAVE APPROACHES. EXPECT A FEW
ISOLATED STORMS TO DEVELOP SOMEWHERE CLOSE TO ABILENE OR SWEETWATER
LATE THIS AFTERNOON AND CONTINUE INTO THE MID EVENING HOURS. NEAR
RECORD HIGH TEMPERATURES HERE IN SAN ANGELO...ALONG WITH DEWPOINTS
AROUND 60...ARE LEADING TO A VERY UNSTABLE AIR MASS. GIVEN CAPE
VALUES IN EXCESS OF 2500 J/KG...IF A STORM CAN DEVELOP...EXPECT IT
TO TRY TO REACH SEVERE LEVELS PRETTY QUICK.
EXPECT FRONT TO DRIFT NORTH THROUGH THE EVENING...PROBABLY BACK INTO
THE NORTHERN BIG COUNTRY BY LATE THIS EVENING...AND BACK OUT OF WEST
CENTRAL TEXAS BY SUNRISE. MILD AGAIN SOUTH OF THE BOUNDARY...WITH
READINGS HAVING A HARD TIME DROPPING BELOW 70. A LITTLE COOLER
ACROSS THE NORTHERN BIG COUNTRY...ALTHOUGH TEMPERATURES THERE MAY
EVEN CLIMB SLIGHTLY BY MORNING.
MAIN UPPER TROUGH MOVING INTO THE ROCKIES WEDNESDAY AFTERNOON. BEST
LIFT WAITS UNTIL WEDNESDAY NIGHT...BUT IT WILL AID THE DRYLINE IN
STRENGTHENING AND MOVING EAST. BY AFTERNOON...DRYLINE WILL LIKELY BE
SOMEWHERE ACROSS THE WESTERN BIG COUNTRY AND CONCHO VALLEY. CAP WILL
STILL BE STRONG...BUT SHOULD BEGIN TO ERODE BY LATE IN THE
AFTERNOON. WILL CONTINUE THE SLIGHT CHANCE POPS DURING THE
AFTERNOON...WITH ODDS INCREASING QUITE A BIT AFTER DARK.
07
.LONG TERM...
CURRENT WEATHER...WV IMAGERY IS SHOWING A TROF AMPLIFYING ACROSS THE
WESTERN US. THIS AFTERNOON...STATIONARY FRONT EXTENDS ACROSS
EXTREME SOUTHEAST OKLAHOMA...NORTHWEST TEXAS AND THE NORTHERN
PERMIAN BASIN. ALSO...MODIFIED ARCTIC HIGH PRESSURE SURFACE RIDGE
WAS OVER MONTANA AND THE NORTHERN PLAINS.
WEDNESDAY NIGHT...HOW ARE THESE TWO FEATURES GOING TO AFFECT WEST
CENTRAL TEXAS WITH POSSIBLE SEVERE WEATHER. THE ALOFT PART IS
PRETTY STRAIGHT FORWARD...WITH TROF INTENSIFYING AND MOVING EAST
PUTTING THE SOUTHERN PLAINS IN STRONG SOUTHWEST FLOW. ALSO...THE
GFS MODEL INDICATING GOOD POLAR AND SUBTROPICAL JET DIVERGENCE AT
POSSIBLE PRIME SEVERE WEATHER TIME/WEDNESDAY AFTERNOON AND NIGHT/.
THE SURFACE PART IS MORE COMPLEX. THE ECMWF AND NAM MODELS ARE
KEEPING THE FRONT FURTHER SOUTH FROM ALONG AN OKLAHOMA CITY TO
TULIA LINE THROUGH WEDNESDAY. THE GFS IS MUCH FURTHER NORTH ALONG
A GUYMON TO KANSAS CITY LINE. THE GFS MAY BE STRUGGLING DUE
PARTLY TO THE WARM EQUATION NUMBERS BEING INPUTED ON APRIL 1ST.
GOING MORE WITH THE NAM AND ECMWF DUE TO ARCTIC AIR ALREADY IN
PLACE TO OUR NORTH AND A NEGATIVE NAO PATTERN STILL OVER THE
EASTERN US. HOWEVER...GOOD SURFACE CYCLOGENESIS IS A GOOD BET
WEDNESDAY OVER THE SOUTHERN PLAINS DUE TO STRONG DYNAMICS JUST
UPSTREAM. THERE ARE A FEW MORE TWISTS AND TURNS IN THIS FORECAST.
STAY TUNED.
THE BEST CHANCE OF MORE WIDESPREAD/POSSIBLY SIGNIFICANT/SEVERE
WEATHER WILL BE WEDNESDAY AND WEDNESDAY NIGHT ACROSS THE SOUTHERN
PLAINS. THE DAY2 OUTLOOK BY SPC OF A MODERATE RISK OVER OKLAHOMA
AND EXTREME NORTHWEST TEXAS LOOKS GOOD. THE WARM SECTOR WILL BE
PRIMED AHEAD OF THE DRYLINE AND SOUTH OF STATIONARY FRONT.
DEWPOINTS WILL BE IN THE MID TO UPPER 60S ALONG WITH STRONG
INSTABILITY/MLCAPES OF 2000 TO 3000 J/KG/. WITH THE ADDITION OF
STRONG SHEAR...SUPERCELLS ARE A GOOD BET MAINLY DURING THE LATE
AFTERNOON AND EARLY EVENING. AT LEAST FOR NOW...THE FRONT WILL
MOVE NORTH TO THE I-40 CORRIDOR BY 00Z THU. SO MORE ORGANIZED
SEVERE CONVECTION IS MORE LIKELY ACROSS THE BIG COUNTRY LATE
WEDNESDAY AFTERNOON AND EVENING. ALSO...THE TEXAS TECH 3KM WRF IS
INDICATING A LINE OF CONVECTION FROM ABILENE TO SAN ANGELO JUST
AFTER MIDNIGHT. THE MAIN HAZARDS WILL BE LARGE HAIL AND DAMAGING
WINDS...ALONG WITH ISOLATED TORNADOES POSSIBLE. GOING WITH LKLY
POPS ACROSS THE FAR EASTERN COUNTIES AND MAINLY CHC ELSEWHERE FOR
WEDNESDAY NIGHT.
THURSDAY THROUGH TUESDAY...COOLER FOR THURSDAY AND FRIDAY WITH
HIGHS MAINLY IN THE 60S. A WARMING TREND BY THIS WEEKEND WITH
HIGHS IN THE UPPER 70S TO LOWER 80S. THE COLDEST MORNING WILL BE
FRIDAY WITH LOWS IN THE 30S. IF SKIES ARE CLEAR AND WINDS
CALM...THEN TEMPS MAY DROP TO NEAR FREEZING...ESPECIALLY IN LOW
LYING AREAS AND RIVER VALLEYS.
21
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 68 86 56 62 36 / 20 20 40 10 5
SAN ANGELO 70 91 58 65 38 / 10 20 30 10 5
JUNCTION 70 89 63 70 39 / 5 20 50 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
908 PM CDT WED APR 17 2013
.UPDATE...
THE HRRR HAS BEEN TRENDING TOWARD PUSHING THE SURFACE BOUNDARY
SOUTH WITH THE HEAVIEST RAINS LATER TONIGHT STAYING A LITTLE MORE
SOUTH ACROSS NORTHERN ILLINOIS...ALTHOUGH SOME MODERATE TO HEAVY
RAIN DOES GET INTO SOUTHERN WISCONSIN.
THE NEW NAM IS PUSHING THE HEAVY RAIN ACROSS SOUTHERN WISCONSIN.
LATEST SATELLITE/RADAR TRENDS FAVOR THE HRRR. HOWEVER THE STRONG
850 MB JET DOES PUSH INTO FAR SOUTHEAST WISCONSIN DURING THE EARLY
MORNING HOURS...SO THE HEAVIER NAM PRECIPITATION CANNOT BE RULED OUT.
WITH RIVERS ALREADY NEAR AND OVER FLOOD...THE ADDED WATER IS STILL
EXPECTED TO MAKE MANY RIVERS REACH MAJOR FLOOD.
&&
.AVIATION/06Z TAFS/...
IFR/LIFR CEILINGS WITH SOME IFR VSBYS WILL CONTINUE INTO THE EARLY
MORNING HOURS WITH A FRONTAL BOUNDARY ACROSS CENTRAL ILLINOIS.
THIS FRONT SHOULD LIFT NORTH AS A WARM FRONT...AS THE SURFACE LOW
REACHES SOUTHEAST WISCONSIN THURSDAY AFTERNOON. STILL EXPECT IFR
CONDITIONS WITH SOME LIFT...ESPECIALLY IN THE VICINITY OF THE THE
SURFACE LOW. SOME THUNDERSTORMS ALSO EXPECTED. LOW LEVEL WIND
SHEAR EXPECTED DURING THE EARLY MORNING HOURS AS THE SOUTH LOW
LEVEL JET MOVES INTO SOUTHEAST WISCONSIN WITH THE EAST WINDS AT
THE SURFACE.
&&
.PREV DISCUSSION... /ISSUED 335 PM CDT WED APR 17 2013/
TONIGHT AND THURSDAY...FORECAST CONFIDENCE IS MEDIUM TO HIGH.
CURRENT AREA OF RAIN AND THUNDER MOVING OUT OF THE AREA FROM WEST TO
EAST. WAKE LOW WIND GUSTS OUT OF THE EAST BETWEEN 30 AND 45 MPH ARE
EXPECTED FOR AN HOUR OR TWO AFTER THE RAIN ENDS. SEE SPECIAL WEATHER
STATEMENT FOR MORE INFORMATION.
BRIEF LULL IN ACTIVITY BEFORE NEXT ROUND OF RAIN AND THUNDERSTORMS
MOVES IN DURING THE EVENING...THEN PERSISTS LATER TONIGHT INTO
THURSDAY. SHORT TERM MODELS IN PRETTY GOOD AGREEMENT WITH TAKING
SURFACE LOW NORTHEAST INTO FAR SOUTHEAST IOWA BY 12Z THURSDAY...THEN
INTO SOUTHERN WISCONSIN BY 00Z FRIDAY. MODELS DIFFERING A BIT WITH
THE EXACT LOCATION OF THE LOW.
STRONG UPWARD VERTICAL MOTION MOVES INTO THE AREA TONIGHT...WITH
STRONG LOW LEVEL JET NOSE POINTING INTO THE AREA. LOW LEVEL
FRONTOGENESIS RESPONSE IS ALSO QUITE STRONG...INTERACTING WITH
COPIOUS AMOUNTS OF MOISTURE. PRECIPITABLE WATER VALUES ON AREA
FORECAST SOUNDINGS ARE UP TO 1.50 INCHES...WHICH IS NEARLY OFF THE
CHARTS FOR MID APRIL. THIS WILL LEAD TO ROUNDS OF THUNDERSTORMS WITH
HEAVY RAINFALL MOVING THROUGH THE AREA BY LATER THIS EVENING AND
INTO THURSDAY MORNING. RISK OF FLASH FLOODING IS THERE WITH ANY
TRAINING CONVECTION AND SATURATED GROUND. ELEVATED CAPES WILL
INCREASE THROUGH THE NIGHT...WHICH MAY LEAD TO HAIL OCCURRING WITH
ANY STRONGER STORMS.
KEPT HEAVY RAINFALL GOING THROUGH THURSDAY AS SURFACE LOW AND WARM
SECTOR AIRMASS MOVES INTO THE AREA...AS HIGH PRECIPITABLE WATER
VALUES REMAIN. EXPECT ANOTHER 1.50 TO 3.50 INCHES OF RAIN ON TOP OF
WHAT HAS ALREADY FALLEN.
SHOULD SEE SCATTERED THUNDERSTORMS DEVELOP WITH SURFACE LOW AND COLD
FRONT MOVING THROUGH THE AREA. SPC HAS AREA IN SLIGHT RISK FOR
SEVERE...WHICH LOOKS GOOD GIVEN DECENT SURFACE BASED CAPES AND
STRONG LOW AND DEEP LAYER SHEAR. DAMAGING WINDS AND LARGE HAIL WOULD
BE THE MAIN HAZARDS...THOUGH COULD NOT RULE OUT AN ISOLATED TORNADO
GIVEN PASSING LOW AND STRENGTH OF LOW LEVEL SHEAR. INSTABILITY
SOMEWHAT IN QUESTION WITH CLOUDS AND PRECIPITATION IN THE AREA. KEEP
UP WITH THE LATEST FORECASTS.
THURSDAY NIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH.
TIMING IS KEY HERE IN THE EARLY HOURS. THE STRONG COLD FRONT WILL
SWEEP EAST OF THE AREA RIGHT AROUND 00Z...GIVE OR TAKE AN HOUR OR
TWO. THE BAND OF HEAVY RAIN SHOULD HEAD OUT WITH IT. TEMPS WILL
THEN CRASH THROUGH THE NIGHT WITH THE SECONDARY COLD FRONT
SWEEPING IN TOWARD 12Z. BETWEEN THESE TWO FRONTS...THE PRECIP MAY
BE NEARLY NON-EXISTENT. SO HIGH POPS IN THE EAST EARLY...A BREAK
INTO THE EARLY MORNING...THEN MORE LIGHT PRECIP ARRIVES LATE AS
THE SECONDARY FRONT COMES THROUGH...ALONG WITH A LAGGING VERY
STRONG UPPER LEVEL TROF.
EXPECT A SLOW TRANSITION FROM LIQUID TO SNOW...MAINLY ACROSS SOUTH
CENTRAL AREAS. BUT BY THE TIME TEMPS TURN COLD ENOUGH FOR ALL
SNOW...THE EXPECT PRECIP AMOUNTS WILL BE LIGHT. SO A DUSTING OF
ACCUM IS ALL THAT/S EXPECTED.
FRIDAY...FORECAST CONFIDENCE IS HIGH.
MAIN ISSUE FOR FRIDAY WILL BE THE WINDS. BEHIND SECONDARY COLD
FRONT...LOW LEVEL LAPSE RATES GET QUITE STEEP AND TAP INTO SOME
BRISK WINDS. SHOULD BE A 20 TO 30 MPH BLOW WITH SOME HIGHER GUSTS.
A CHILLY DAY WITH HIGHS IN THE UPPER 30S TO LOWER 40S.
SATURDAY AND SUNDAY...FORECAST CONFIDENCE IS MEDIUM.
GENERALLY A QUIET WEEKEND...THOUGH WE COULD SEE SOME RAIN MOVE IN
LATER ON SUNDAY WITH THE APPROACH OF THE NEXT TROUGH OF LOW
PRESSURE. TEMPS MODIFY EACH DAY AS THE FLOW BACKS TO THE SOUTH
AHEAD OF THE TROF.
MONDAY INTO WEDNESDAY...FORECAST CONFIDENCE IS LOW TO MEDIUM.
THIS LOOKS UNSETTLED AGAIN WITH A SLOW MOVING TROF POTENTIALLY
BRINGING A FEW ROUNDS OF RAIN DURING THE PERIOD. THE MODELS AGREE
ON THE OVERALL TREND FOR EARLY NEXT WEEK...BUT DIFFER ON
SPECIFICS.
AVIATION/00Z TAFS/...
A WAKE LOW SITUATION HAS DEVELOPED BEHIND THE BACKSIDE OF SHOWERS
AND THUNDERSTORMS. WAKE LOW PARAMETERS AND ESTIMATE MAX GUSTS SHOW A
STRONG SIGNAL AND COINCIDE WELL WITH LOCATION OF SFC OBS REPORTING
GUSTS...THOUGH GUST MAGNITUDES TOO HIGH. THUS...2-HR TEMPO ADDED
THOUGH UNCERTAINTY EXISTS WITH TIMING FOR GUSTY WINDS ON THE BACK
EDGE OF PRECIP SHIELD WITH GUSTS UP TO 30-45 MPH.
BACK EDGE OF PRECIPITATION SHIELD IS APPARENT ON THE RADAR MOSAIC
SHOWS...ENDING OF PRECIP AT UES...MKE...ENW...BETWEEN 330 AND 430
PM. REPRIEVE IN ACTIVITY WILL BE SHORT IN THE MID AFTERNOON...WITH
LIGHT ISOLATED SHOWERS POSSIBLE. REDEVELOPMENT OF SHOWERS AND
SCATTERED THUNDERSTORMS EXPECTED FROM SOUTHWEST TO NORTHEAST BETWEEN
0-3 UTC.
FLIGHT CATS WILL DROP TO IFR WITH 500-1000 FEET CIGS THIS EVENING
WITH REDEVELOPMENT...REMAINING THERE THROUGH THU. VSBYS WILL
GENERALLY RANGE FROM 1-4 MILES DURING THIS PERIOD. MODERATE TO HEAVY
RAINFALL WITH THUNDERSTORMS ARE EXPECTED OVERNIGHT INTO THURSDAY.
MARINE...
WILL ISSUE MARINE WEATHER STATEMENT OR SPECIAL MARINE WARNING FOR
WAKE LOW WIND GUSTS BETWEEN 30 AND 40 KNOTS OVER THE NEARSHORE
WATERS THROUGH 00Z THURSDAY.
GUSTY OFFSHORE WINDS EXPECTED THURSDAY NIGHT THROUGH FRIDAY ACROSS
THE NEARSHORE WATERS...AS LOW PRESSURE STRENGTHENS AND MOVES
NORTHEAST OF THE AREA. HIGH WAVES WILL OCCUR TOWARD THE OPEN WATERS
DURING THIS TIME. A SMALL CRAFT ADVISORY MAY BE NEEDED IN LATER
FORECASTS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...FLOOD WATCH THROUGH FRIDAY MORNING FOR WIZ046-047-051-052-
056>060-062>072.
LM...SMALL CRAFT ADVISORY UNTIL 9 AM CDT THURSDAY FOR LMZ643>646.
&&
$$
UPDATE...HENTZ
TONIGHT/THURSDAY AND AVIATION/MARINE...ET
THURSDAY NIGHT THROUGH WEDNESDAY...DAVIS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
904 PM CDT WED APR 17 2013
.UPDATE...
ISSUED AT 904 PM CDT WED APR 17 2013
THE NEXT BAND OF RAIN IS CURRENTLY MOVING THROUGH THE REGION AND
SHOULD LAST THROUGH THE NEXT 2 TO 4 HOURS PROVIDING ABOUT 0.20 TO
0.40 OF AN INCH OF RAIN. WITH THE MAIN AXIS OF LOW LEVEL MOISTURE
TRANSPORT AND HIGHER INSTABILITY STAYING TO THE SOUTHEAST INTO
TOMORROW...HAVE DECIDED TO DROP THE FLOOD WATCH FOR THE
NORTHWESTERN HALF OF THE FORECAST AREA. WILL HAVE AN UPDATE COMING
OUT SHORTLY WITH THIS CANCELLATION. OTHERWISE...LIGHTNING HAS
REALLY DWINDLED OVER THE PAST FEW HOURS AS THIS RAIN HAS RUN INTO
THE REGION THAT HAS LITTLE TO NO INSTABILITY. THE LAST FEW RUNS OF
THE RAP HAVE KEPT THE HIGHER 0-3KM MUCAPE OFF TO THE EAST OF THE
FORECAST AREA AS WELL...SO AM NOT ANTICIPATING MUCH IN THE WAY OF
HAIL TO OCCUR. DUAL POL RADAR ANALYSIS SHOWS SOME BRIGHT BANDING
AS WELL AROUND 6-7KFT WITH ALL LIQUID PRECIPITATION LIKELY MAKING
IT DOWN TO THE GROUND.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 305 PM CDT WED APR 17 2013
MAIN FORECAST CONCERNS ARE ON HEAVY RAINFALL TONIGHT THROUGH
THURSDAY AND LARGE HAIL POTENTIAL THIS EVENING INTO THE OVERNIGHT
HOURS. FOCUS THEN TURNS TO PERSISTENT RAINFALL THROUGH THE DAY ON
THURSDAY...WITH PRECIPITATION SWITCHING OVER TO SNOW THURSDAY
NIGHT.
LATEST WATER VAPOR IMAGERY SHOWED A POTENT TROUGH DIGGING INTO THE
FOUR CORNERS REGION WITH SOUTHWEST FLOW ALOFT SETTING UP OVER THE
UPPER MISSISSIPPI RIVER VALLEY. A MOIST...UNSTABLE AIRMASS WAS
ADVECTING NORTHWARD OUT OF THE MIDDLE MISSISSIPPI RIVER VALLEY AND
INTERACTING WITH SHORTWAVE ENERGY EMBEDDED IN THE SOUTHWEST FLOW.
SHOWERS AND THUNDERSTORMS HAVE BEEN ONGOING ACROSS ACROSS MUCH OF
IOWA THROUGH NORTHERN ILLINOIS AND FAR SOUTHWEST WISCONSIN.
THE SURGE OF MOIST UNSTABLE AIR CONTINUES ITS NORTHWARD PROGRESSION
TONIGHT ON THE NOSE OF A STRONG LOW LEVEL JET. PRECIPITABLE WATER
VALUES CLIMB INTO THE 1 TO 1.5 INCH RANGE...WHICH IS 160 TO 230
PERCENT OF NORMAL. ALSO...MUCAPE VALUES INCREASE TO AROUND 1500J/KG
ACROSS EXTREME NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN THIS
EVENING INTO THE OVERNIGHT HOURS...WHERE A FEW STORMS COULD PRODUCE
LARGE HAIL. WARM CLOUD DEPTHS ALSO INCREASE TONIGHT TO AROUND 3000 M
WHICH ALSO IS CONDUCIVE TO HEAVY RAIN POTENTIAL. OVERALL SHEAR IS
RATHER WEAK TONIGHT WITH 1 TO 7 KM BULK SHEAR VALUES OF ONLY 15 TO
25 KTS. A STRONG BAROCLINIC ZONE SETS UP ACROSS THE AREA WITH THE
WARMEST AIR LOCATED AROUND 925 MB. PLENTY OF SUPPORT FOR SHOWERS AND
THUNDERSTORMS TONIGHT ACROSS THE FORECAST AREA WITH THE BAROCLINIC
ZONE COLLOCATED WITH THE RIGHT ENTRANCE REGION OF A 250 MB JET.
FORECAST MODELS HAVE BEEN TRENDING SLIGHTLY MORE SOUTHEAST WITH THE
HEAVIER RAINFALL AMOUNTS KEEPING THE HIGHEST TOTALS GENERALLY
SOUTHEAST OF AN OELWEIN IOWA TO MAUSTON WISCONSIN LINE. 2 TO 3
INCHES OF RAINFALL ARE POSSIBLE OVER THESE AREAS WITH 1 TO 2 INCHES
POSSIBLE FOR LOCATIONS TO THE NORTH AND WEST. HOWEVER...THIS WILL
GREATLY DEPEND UPON WHICH AREAS THE THUNDERSTORMS TRAIN OVER. FLASH
FLOODING IS POSSIBLE TONIGHT IF RAINFALL RATES BECOME HIGH ENOUGH.
THE HIGHEST CHANCES FOR FLASH FLOODING APPEAR TO BE OVER EXTREME
SOUTHWEST WISCONSIN...MAINLY GRANT...CRAWFORD...AND RICHLAND
COUNTIES. WILL HAVE TO KEEP A VERY CLOSE EYE ON THIS SITUATION
DURING THE OVERNIGHT HOURS. SHOWERS AND ISOLATED THUNDERSTORMS WILL
BE ONGOING INTO THURSDAY MORNING THEN THE HEAVIER RAINFALL WILL
FINALLY SHIFT SOUTHEAST OF THE AREA BY THURSDAY AFTERNOON AS THE
TROUGH LIFTS NORTH INTO EASTERN SOUTH DAKOTA/NEBRASKA AND CLOSES
INTO AN UPPER LOW. COLDER AIR FILTERS INTO THE REGION FROM THE WEST
ON THURSDAY POTENTIALLY BRING SOME SNOW TO THE FORECAST AREA. A DRY
SLOT PUNCHES INTO THE AREA FROM THE SOUTHWEST ON THURSDAY WITH THE
FORECAST AREA LOSING DEEP SATURATION. LIGHT RAIN WILL SWITCH OVER TO
DRIZZLE AS THE DRY SLOT MOVES IN. THE UPPER LOW IS EXPECTED TO MOVE
ACROSS SOUTHWEST MINNESOTA LATE THURSDAY AFTERNOON THEN ADVANCE
NORTHEAST INTO EAST CENTRAL MINNESOTA THURSDAY EVENING. A BAND OF
SNOW WILL FALL ON THE THE NORTHERN SIDE OF THE LOW TRACK FROM
EASTERN SOUTH DAKOTA...INTO CENTRAL MINNESOTA THROUGH NORTHERN
WISCONSIN. THE BULK OF THE FORECAST AREA WILL NOT SEE ICE ALOFT SO
WHERE TEMPERATURES DROP BELOW FREEZING SOME LIGHT FREEZING DRIZZLE
OR FREEZING RAIN IS POSSIBLE...ESPECIALLY THURSDAY EVENING AS
SURFACE TEMPERATURES FALL BELOW FREEZING. ICE FINALLY MOVES IN ALOFT
THURSDAY NIGHT. ACROSS PORTIONS OF SOUTHEAST MINNESOTA THROUGH NORTH
CENTRAL WISCONSIN...PLAN ON SNOW ACCUMULATIONS OF 1 TO 3 INCHES.
NORTHEAST IOWA INTO SOUTHWEST AND CENTRAL WISCONSIN SHOULD SEE
ACCUMULATIONS OF 1/2 INCH TO AROUND AN INCH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT WED APR 17 2013
THE LOW IS EXPECTED TO GRADUALLY PROGRESS NORTHEAST INTO WESTERN
UPPER MICHIGAN EARLY FRIDAY MORNING. SNOW SHOWERS WILL CONTINUE
ACROSS MUCH OF THE AREA FRIDAY MORNING...THEN SWITCHING OVER MAINLY
TO RAIN SHOWERS FRIDAY AFTERNOON. PLAN ON BREEZY WEST/NORTHWEST
WINDS THURSDAY NIGHT THROUGH FRIDAY WITH A TIGHT PRESSURE GRADIENT
OVER THE REGION WITH SPEEDS OF 15 TO 25 MPH WITH GUSTS TO AROUND 35
MPH POSSIBLE...ESPECIALLY DURING THE DAY ON FRIDAY. HIGH
TEMPERATURES ON FRIDAY WILL RANGE FROM THE LOWER 30S OVER NORTHERN
WISCONSIN TO AROUND 40 ACROSS NORTHEAST IOWA. CHILLY NORTHWEST FLOW
CONTINUES ACROSS THE REGION FRIDAY NIGHT THROUGH SATURDAY AS HIGH
PRESSURE BUILDS IN. THERE WILL BE A BRIEF BREAK IN PRECIPITATION
CHANCES DURING THE DAY ON SATURDAY AHEAD OF ANOTHER TROUGH MOVING IN
FROM THE NORTHERN PLAINS. SKIES WILL START OUT MOSTLY SUNNY ON
SATURDAY WITH INCREASING CLOUD EXPECTED DURING THE AFTERNOON HOURS.
PLAN ON HIGHS ON SATURDAY RANGING FROM AROUND 40 OVER NORTH CENTRAL
WISCONSIN TO THE UPPER 40S ACROSS NORTHEAST IOWA. THE HIGH QUICKLY
SLIDES OFF TO THE EAST SATURDAY NIGHT. THE TROUGH LOOKS TO MOVE INTO
THE UPPER MISSISSIPPI RIVER VALLEY ON SUNDAY SPREADING SHOWERS
ACROSS THE AREA. IF THE PRECIPITATION SPREADS IN SATURDAY NIGHT...A
WINTER MIX IS POSSIBLE. ACTIVE SOUTHWEST FLOW SETS UP ONCE AGAIN
ACROSS THE REGION GOING INTO NEXT WEEK AS A TROUGH DEVELOPS OVER
THE CENTRAL CONUS. SEVERAL WAVES EJECT NORTHEAST OUT OF THE TROUGH
AND HAVE THE POTENTIAL TO BRING A FEW ROUNDS OF SHOWERS AND
THUNDERSTORMS TO THE AREA. MAJOR DIFFERENCES NOTED IN THE TIMING
OF THESE WAVES AND EXACTLY HOW THE TROUGH EVOLVES TUESDAY INTO
WEDNESDAY SO WILL HAVE TO KEEP A VERY CLOSE WATCH ON THIS
SITUATION.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 641 PM CDT WED APR 17 2013
LIFR TO MVFR CONDITIONS TO PERSIST THROUGH TOMORROW AFTERNOON AS A
POTENT LOW PRESSURE SYSTEM MOVES THROUGH THE REGION. CEILINGS AND
VISIBILITY HAVE DROPPED AT RST AS A BAND OF DRIZZLE HAS MOVED IN
ACROSS MUCH OF SOUTHEAST MINNESOTA. THE NEXT ROUND OF SHOWERS AND
THUNDERSTORMS IS TIMED TO MOVE INTO THE REGION AROUND 1Z AND
SHOULD BE THROUGH BY 5Z. THESE SHOWERS MAY BRIEFLY BRING
CONDITIONS UP A FLIGHT CATEGORY...BUT THEY SHOULD DROP BACK DOWN
AFTER THE WAVE MOVES THROUGH AND ANOTHER ROUND OF DRIZZLE MOVES
IN. CONFIDENCE IS NOT VERY HIGH WITH WHEN THE NEXT WAVE OF SHOWERS
MOVES IN AFTER THIS...BUT IT APPEARS THAT SOMETIME AROUND 11Z OR
12Z IS WHEN THE SHORT TERM FORECAST GUIDANCE BRINGS IT IN. BEYOND
THIS...OFF AND ON PERIODS OF DRIZZLE AND RAIN SHOWERS WILL PERSIST
THROUGH TOMORROW AFTERNOON WITH THE IFR/MVFR CONDITIONS CONTINUING.
&&
.HYDROLOGY...TONIGHT THROUGH THURSDAY
ISSUED AT 305 PM CDT WED APR 17 2013
FLOOD WATCH IN EFFECT THROUGH THURSDAY NIGHT.
A VERY MOIST AIR MASS WILL MOVE INTO THE AREA TONIGHT FROM THE MIDDLE
MISSISSIPPI RIVER VALLEY...WITH PRECIPITABLE WATER VALUES IN THE
1-1.5 INCH RANGE WHICH IS 160 TO 230 PERCENT ABOVE NORMAL. THIS
MOISTURE TRANSPORT AND LIFT...COUPLED WITH UPPER LEVEL DYNAMICS
WILL TAP THIS MOISTURE TO PRODUCE 1 TO 3 INCHES OF RAINFALL
TONIGHT THROUGH THURSDAY NIGHT. THE HIGHEST AMOUNTS WILL LIKELY BE
FOCUSED ACROSS NORTHEAST IA INTO SOUTHWEST WI. ALSO...IF
THUNDERSTORMS TRAIN OVER AREAS...FLASH FLOODING IS POSSIBLE
TONIGHT INTO EARLY THURSDAY MORNING MAINLY OVER EXTREME NORTHEAST
IOWA INTO FAR SOUTHWEST WISCONSIN.
WITH MANY RIVERS RUNNING HIGH OR ALREADY IN FLOOD...THIS
RAINFALL...ALONG WITH SNOW MELT FROM THE SNOW PACK NORTH OF
WISCONSIN HIGHWAY 10 AND STILL SOME FROZEN GROUNDS...WILL HEIGHTEN
THE FLOOD THREAT. MANY RIVERS WILL GO INTO...OR BACK INTO...FLOOD.
IN ADDITION...THERE WILL BE PONDING OF WATER ON ROADWAYS ALONG WITH
STANDING WATER IN LOW LYING AND POOR DRAINAGE AREAS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FLOOD WATCH THROUGH LATE THURSDAY NIGHT FOR WIZ042>044-053>055-
061.
MN...NONE.
IA...FLOOD WATCH THROUGH LATE THURSDAY NIGHT FOR IAZ011-029-030.
&&
$$
UPDATE...HALBACH
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...HALBACH
HYDROLOGY...WETENKAMP
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND WEDNESDAY
ISSUED AT 308 PM CDT TUE APR 16 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE
CENTERED OVER CENTRAL CANADA AND A RIDGE AXIS EXTENDING INTO THE
NORTHERN MISSISSIPPI VALLEY. A WEAK COLD FRONT IS EXTENDING ACROSS
LAKE SUPERIOR AND NORTHERN MINNESOTA...WHICH IS CONTRIBUTING TO THE
WIDESPREAD STRATO-CU FIELD OVER NORTHERN PARTS OF WISCONSIN. THIS
STRATO-CU FIELD HAS BEEN SLOWLY RETREATING NORTHWARD THIS
AFTERNOON...AND CLEARING SKIES ARE NOW APPROACHING WAUSAU AND
MARINETTE AT THIS HOUR. MEANWHILE...CONVECTION IS OCCURRING NORTH
OF A STATIONARY FRONT LOCATED ACROSS THE OHIO VALLEY. AS THIS FRONT
LIFTS NORTH TOMORROW...THE MAIN FORECAST CONCERN BECOMES TIMING OF
THE INCOMING PRECIPITATION.
TONIGHT...AS CONVERGENCE ALONG A REINFORCING COLD FRONT
WEAKENS...CANADIAN HIGH PRESSURE WILL FEED IN DRIER AIR...BROUGHT IN
BY LIGHT NE WINDS. MAY SEE SCT CLOUD COVER LINGER INTO THE EARLY
EVENING HOURS OVER N-C WISCONSIN BEFORE DRY AIR EVENTUALLY WINDS OUT
AND SKIES TURN MOSTLY CLEAR. IF AND WHEN THIS OCCURS...TEMPS WILL
HAVE POTENTIAL TO TANK OVER N-C WISCONSIN WHERE THERE REMAINS DEEP
SNOW PACK. HAVE DROPPED LOW TEMPS CONSIDERABLY. OTHERWISE...A WARM
FRONT WILL BE LIFTING NORTH ACROSS THE MID-MISSISSIPPI VALLEY...AND
MID CLOUDS WILL SPREAD NORTH OVER CENTRAL AND EAST-CENTRAL WISCONSIN
AFTER MIDNIGHT. THE DRY AIR FEED TO KEEP PRECIP WELL SOUTH OF THE
REGION THOUGH. LOWS RANGING FROM AROUND 20 DEGREES NORTH TO THE MID
30S SOUTH.
WEDNESDAY...THE WARM FRONT WILL CONTINUE TO GRADUALLY LIFT NORTH
OVER CENTRAL AND NORTHERN ILLINOIS. DRY NE FEED OF AIR WILL TRY TO
HOLD BACK PRECIP DURING THE MORNING...AND IT LOOKS LIKE MODELS HAVE
SLOWED THE NORTHERLY PROGRESS OF PRECIP CHANCES. WILL GO DRY WITH
THE FORECAST THROUGH 18Z. AFTER THAT TIME THOUGH...SOUTHWEST FLOW
WILL STRENGTHEN OVER THE FRONT...WHICH SHOULD LEAD TO PRECIP MOVING
INTO CENTRAL AND EAST-CENTRAL WISCONSIN DURING THE AFTERNOON. THE
PRECIP WILL BE FIGHTING THE DRY AIR...SO THINK THE HEAVIER RAIN WILL
NOT ARRIVE UNTIL WEDNESDAY NIGHT...AND FAR NE WISCONSIN MAY NOT SEE
A DROP UNTIL AFTER 00Z AS WELL. HIGH TEMPS WILL LIKELY OCCUR MIDDAY
OR EARLY AFTERNOON BEFORE CLOUDS THICKEN AND/OR PRECIP STARTS
FALLING. PTYPE LIKELY TO BE TRICKY OVER N-C WISCONSIN WHERE THERE
WILL BE A +4C WARM NOSE ABOVE SURFACE TEMPS NEAR FREEZING. PREVIOUS
SHIFT INCLUDED A RAIN/SLEET MIX...AND THAT LOOKS GOOD COMPARED TO
THE PROJECTED SURFACE WET BULB TEMPS. HIGHS IN THE LOW TO MID 40S.
.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
ISSUED AT 308 PM CDT TUE APR 16 2013
ACTIVE AND COMPLEX WEATHER SITUATION WITH POTENTIAL FOR A COUPLE
ROUNDS OF SIGNIFICANT PRECIPITATION FOR THE SECOND HALF OF THE
WORK WEEK. SIGNIFICANT TROUGH WILL GRADUALLY SWING INTO THE HIGH
PLAINS BY 12Z THURSDAY AND BECOME NEGATIVELY TILTED AND DEEPEN BY
FRIDAY AFTERNOON.
AS PREVIOUSLY ADVERTISED...STRONG 850 MB JET WILL DEVELOP OVER THE
PLAINS EARLY WEDNESDAY EVENING AND WILL BE THE DRIVING FORCE FOR
STRONG WAA/LIFT AND SIGNIFICANT MOISTURE TRANSPORT INTO THE WESTERN
GREAT LAKES WEDNESDAY NIGHT. LARGE AREA OF MODERATE TO HEAVY
PRECIPTATION IS FORECAST TO BREAKOUT FROM EASTERN NEBRASKA TO
SOUTHWEST WISCONSIN AND SPREAD NORTHEAST ACROSS THE FORECAST AREA
OVERNIGHT INTO EARLY THURSDAY. PRECIPITABLE WATER VALUES OVER THE
MISSISSIPPI VALLEY NORTHWARD INTO WISCONSIN EXPECTED TO BE WELL
ABOVE NORMAL FOR THIS TIME OF YEAR. COMBINATION OF STRONG
FORCING...ANOMALOUSLY HIGH PRECIPITABLE WATER WILL LEAD MODERATE TO
HEAVY RAINFALL. THE GENERAL CONCENSUS OF THE LATEST GUIDANCE SEEMS
TO BE FOCUSING THE MAXIMUM QPF OVER ABOUT THE SOUTHEAST THIRD OF THE
STATE. HELD ONTO THUNDER POTENTIAL...ESPECIALLY OVER THE FOX VALLEY
AS WELL WEDNESDAY NIGHT. CANADIAN MODEL WAS FURTHEST NORTH THAN THE
OTHER GUIDANCE DURING THIS PERIOD...THUS WAS DISCONTED. THE AREA OF
HEAVIEST RAINFALL SHOULD BE EAST OF THE FORECAST AREA BY AROUND NOON
THURSDAY. ACROSS THE NORTHWEST PORTION OF THE FOPRECAST
AREA...APPEARS BOUNDARY LAYER TEMPERATURES WILL BE VERY CLOSE TO
FREEZING...THUS STILL FEEL THERE IS POTENTIAL FOR SOME FREEZING
RAIN...MIXED WITH SLEET AND WET SNOW PARTICULARLY IN THE 06Z TO 12Z
PERIOD THURSDAY MORNING.
UPPER SYSTEM THEN BECOMES NEGATIVELY TILTED THURSDAY EVENING WITH
SURFACE WAVE RAPIDLY INTENSIFYING. PROBLEM IS THAT STILL MUCH
DESCREPANCY IN MODEL GUIDANCE WITH RESPECT TO THE RATE OF
DEEPENING AND MOVEMENT OF THE SURFACE LOW. THUS...HAD TO REAMIN
SOMEWHAT BROAD BRUSH ON QPF AMOUNTS ACROSS THE FORECAST AREA. IT
DOES APPEAR THAT BY EARLY FRIDAY MORNING ENOUGH COLD AIR WILL BE
DRAWN INTO THE SYSTEM TO TURN THE PRECIPITATION OVER TO SNOW. LATER
SHIFTS SHOULD BE ABLE GET A BETTER HANDLE ON THE SYSTEM EVOLUTION
AND ASSOCIATED PRECIPITATION TYPES.
GIVEN THE POTENTIAL FOR A COUPLE ROUNDS OF MODERATE TO HEAVY
RAINFALL...MELTING SNOW AND MANY RIVERS AT OR ABOVE FLOOD STAGE
ALREADY...AREAL FLOOD WATCH HAS BEEN ISSUED. SEE ASSOCIATED
HYDROLOGY DISCUSSION FOR DETAILS BELOW.
LOOKS LIKE QUIETER AND DRIER CONDITIONS TO RETURN OVER THE
UPCOMING WEEKEND...ALTHOUGH TEMPERATUES WILL REMAIN WELL BELOW
NORMAL INTO EARLY NEXT WEEK.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1222 PM CDT TUE APR 16 2013
12Z SOUNDINGS INDICATE CLOUD COVER OVER CENTRAL AND
NORTHERN WISCONSIN IS RELATIVELY SHALLOW...SO ANTICIPATING CLOUDS TO
BREAK UP WITH HEATING THIS AFTERNOON. REGARDLESS...CIGS SHOULD
INCREASE TO VFR THIS AFTERNOON. HIGH PRESSURE WILL THEN HANG AROUND
THE REGION TONIGHT AS MID CLOUDS INCREASE AHEAD OF THE NEXT SYSTEM
DEVELOPING OVER THE PLAINS. A WARM FRONT THEN LIFTS NORTH INTO
NORTHERN ILLINOIS ON WEDNESDAY. CLOUDS WILL LOWER AND THICKEN
THROUGH THE DAY AS MOISTURE FLOWS NORTH. INITIAL LOW LEVEL DRY AIR
WILL HOLD BACK THE PRECIPITATION SOMEWHAT...BUT STILL EXPECT LIGHT
RAIN...POSSIBLY MIXED WITH SNOW OVER NORTHERN WISCONSIN TO ARRIVE
WEDNESDAY AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 308 PM CDT TUE APR 16 2013
POTENTIAL OF FLOODING ON THE INCREASE THIS WEEK WITH EVEN LONG
TERM ISSUES THROUGH APRIL.
A STRENGTHENING LOW PRESSURE SYSTEM WILL TRACK NORTHEAST TOWARD THE
GREAT LAKES REGION THROUGH FRIDAY. GULF MOISTURE WILL WORK
NORTHWARD TO PRODUCE WELL ABOVE NORMAL PRECIPITABLE WATER AMOUNTS
FOR THIS TIME OF THE YEAR. RIVERS OVER MUCH OF CENTRAL AND EAST
CENTRAL WISCONSIN ALREADY RUNNING HIGH. ADDITIONAL OR LINGERING
SNOW MELT WILL BE AVAILABLE OVER CENTRAL WISCONSIN RIVERS WHILE
AREAS WITH LITTLE SNOW LEFT...THE GROUND IS SATURATED ALONG WITH A
DEPARTING FROST TO PRODUCE ABOVE NORMAL RUN OFF. CONSENSUS OF
AVAILABLE MODEL RUNS FOR A TOTAL RAINFALL AMOUNT FROM LATE
WEDNESDAY AFTERNOON THROUGH FRIDAY MORNING INDICATE AROUND 2
INCHES OF RAIN SOUTHEAST OF A LINE FROM GREEN BAY TO WAUTOMA...AND
UP TO 1.5 INCHES NORTHWARD. THE RAIN WILL BE FOCUSED ALONG OR NEAR
A SOUTHWEST TO NORTHEAST BOUNDARY EXTENDING OVER SOUTHEAST
WISCONSIN. ANY THUNDERSTORMS WHICH CAN DEVELOP...WILL LIKELY
INCREASE THE RAINFALL TOTALS. NORTH CENTRAL WISCONSIN COULD SEE A
RAIN TO SNOW MIX BY FRIDAY FOR LESSER RAINFALL BUT ADDITIONAL
SNOWFALL TO THE PERSISTENT SNOW PACK. WILL ISSUE A FFA AREAL FLOOD
WARNING FOR CENTRAL AND EAST CENTRAL WISCONSIN THROUGH FRIDAY.
WILL CONSIDER AN ESF NORTH. THE AREAL FLOOD WARNING WILL LIKE
TRANSITION TO RIVER FLOOD WARNINGS BY THIS WEEKEND.
FOR A LONGER TERM FLOODING ISSUE DEVELOPING...THE INCREASING FLOWS
ON THE FOX AND WOLF RIVERS COMING INTO LAKE WINNEBAGO WILL
EVENTUALLY CAUSE THE LAKE TO RISE AND REMAIN FAIRLY HIGH FOR MUCH
OF APRIL IF PERIODS OF RAIN CONTINUE. THE COMBINATION OF STRONG
WINDS WITH HIGHER THAN NORMAL LAKE WINNEBAGO LAKE LEVELS WILL
INCREASE THE POTENTIAL OF SHORELINE FLOODING. HIGH LAKE WINNEBAGO
LEVELS WILL LIKELY TEND TO PRODUCE LONG TERM HIGH LEVELS UPSTREAM
ON THE WOLF AND FOX RIVERS THROUGH APRIL...AGAIN DEPENDING
ADDITIONAL RAINFALL.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY MORNING FOR
WIZ020>022-030-031-035>040-045-048>050-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......ESB
AVIATION.......MPC
HYDROLOGY......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1213 PM CDT TUE APR 16 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 354 AM CDT TUE APR 16 2013
WATER VAPOR IMAGERY AND RAP 500MB ANALYSIS SHOWS A BROAD/RELATIVELY
DEEP UPPER TROUGH AXIS SITUATED OVER THE WEST COAST/INTERMOUNTAIN
REGION. SOUTHWEST FLOW ALOFT OUT F THIS TROUGH WAS SPILLING QUITE A
BIT OF MID/HIGH CLOUD INTO THE REGION. AT THE SURFACE...THE FORECAST
AREA WAS STILL UNDER THE INFLUENCE OF THE LOW PRESSURE THAT BROUGHT
A WINTRY MIX/RAINFALL INTO THE AREA OVER THE WEEKEND. CYCLONIC FLOW
AROUND THE LOW OVER SOUTHERN ONTARIO WAS PRODUCING AN EXTENSIVE
STRATOCUMULUS FILED ACROSS NORTHERN MN INTO NORTHER WI.
OTHERWISE...TEMPERATURES AT 3 AM WERE IN THE 30S.
MAIN FORECAST CHALLENGE IN THE SHORT TERM WILL BE CLOUDS AND
TEMPERATURES THROUGH TONIGHT.
16.00Z NCEP MODEL SUITE AS WELL AS THE ECMWF AND GEM ALL IN GOOD
AGREEMENT IN THE SHORT TERM.
FOR TODAY...WILL SEE THE LOW OVER ONTARIO LIFT FARTHER EAST INTO
QUEBEC...WITH HIGH PRESSURE BUILDING IN FROM THE NORTHERN PLAINS.
THIS WILL KEEP US DRY...BUT SOUTHWEST FLOW ALOFT WILL CONTINUE TO
SPILL MID/HIGH CLOUD INTO THE REGION. NOT TOO CONFIDENT HOW THICK
THIS CLOUD COVER WILL BE. BUFKIT SHOWS ALTERNATE THICKENING/THINNING
THROUGH THE DAY. FEEL WE SEE SOMEWHERE BETWEEN 40-60 PERCENT
OPAQUENESS FOR PARTLY TO MOSTLY SUNNY CONDITIONS. TEMPERATURES TODAY
EXPECTED TO TOP OFF IN THE MIDDLE 40S ACROSS NORTH CENTRAL WI...TO
THE LOWER 50S ACROSS PORTIONS OF NORTHEAST IOWA INTO SOUTHWEST WI.
CLOUDS WILL THEN THICKEN TONIGHT AHEAD OF FAIRLY STRONG CYCLOGENESIS
EAST OF THE COLORADO ROCKY MOUNTAIN FRONT WITH INCREASING MOISTURE
TRANSPORT AND ISENTROPIC LIFT. MOISTURE WILL BE BATTLING DRY AIR
INITIALLY...BUT FEEL SOME RAIN WILL BE POSSIBLE ACROSS NORTHEAST
IA/SOUTHEAST MN/FAR SOUTHWEST WI TOWARD MORNING. OTHERWISE...WITH
THICKENING CLOUDS...LOOK FOR TEMPERATURES TO RANGE FROM NEAR 30
ACROSS NORTH CENTRAL WI...TO THE MIDDLE AND UPPER 30S ACROSS
NORTHEAST IA INTO SOUTHWEST WI.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 354 AM CDT TUE APR 16 2013
LOOK FOR RAIN TO OVERSPREAD THE AREA ON WEDNESDAY AS STRONG LOW
PRESSURE MOVING OUT INTO THE PLAINS INCREASES MOISTURE TRANSPORT
INTO THE AREA. NAM ALSO INDICATING SOME ELEVATED MUCAPE OF A COUPLE
HUNDRED J/KG GOING INTO THE AFTER NOON FOR PERHAPS A CLAP OR TWO OF
THUNDER.
RAINFALL EXPECTED TO REALLY PICK UP OVER THE AREA WEDNESDAY
AFTERNOON/NIGHT AS THE LOW MOVES FROM MO INTO SOUTHEAST WI. SREF
INDICATING INCREASING 850-700MB FRONTOGENESIS OVER THE FORECAST AREA
NORTHWEST OF THE LOW ALONG WITH INCREASING MOISTURE TRANSPORT...
WITH PRECIPITABLE WATERS MOVING INTO THE 1-1.5 INCH RANGE. RAIN
RATES COULD GET MODERATE TO HEAVY AT TIMES GIVEN THIS SCENARIO. RAIN
THEN EXPECTED TO TAPER OFF ON THURSDAY AS THE LOW PULLS INTO LOWER
MI. THINKING THAT FOCUSED FORCING ALONG WITH MUCH HIGHER THAN NORMAL
PRECIPITABLE WATER VALUES WILL YIELD RAINFALL AMOUNTS SOMEWHERE IN
THE 1.5-3.5 INCH RANGE WITH A FEW LOCALLY HIGHER AMOUNTS GIVEN THE
EMBEDDED THUNDERSTORM POTENTIAL. HYDROLOGY EXPECTED TO BECOME AN
ISSUE ONCE AGAIN WITH RIVERS RUNNING FAIRLY HIGH RIGHT NOW. MORE ON
THIS IS COVERED IN THE HYDROLOGY SECTION BELOW. CONCERN IS
INCREASING THAT A FLOOD WATCH MAY BECOME NECESSARY AS WELL WITH
SATURATED GROUND AND POTENTIAL FOR OVERLAND FLOODING IN ADDITION TO
RIVER FLOODING SINCE OUR 6-HRLY FLASH FLOOD GUIDANCE IS ONLY RUNNING
2-3 INCHES. WILL HAVE THE DAY SHIFT ASSESS THIS WITH THE 12Z MODEL
RUNS.
ATTENTION THEN TURNS TO SIGNIFICANT SNOWFALL POTENTIAL FOR THURSDAY
NIGHT INTO FRIDAY. MODELS ARE BECOMING MORE IN AGREEMENT AND
CONSISTENT WITH INCREASING SNOW SIGNAL FOR THE AREA. ECMWF/GFS/GEM
ALL BRING ANOTHER WAVE OF LOW PRESSURE UP ALONG THE EXISTING
BAROCLINIC ZONE AS A VIGOROUS MID-LEVEL TROUGH/CLOSED LOW MOVES
TOWARD THE AREA FROM THE PLAINS. STRONG DEFORMATION ZONE THEN SETS
UP ACROSS THE NORTHWEST HALF OF THE FORECAST AREA. LATEST GFS COB
WANTS TO PRODUCE 8+ INCHES/LOCALLY HIGHER AMOUNTS NORTHWEST OF A
LINE ROUGHLY RUNNING FROM MEDFORD AND LA CROSSE WI...TO NEAR OELWEIN
IA. HEADLINES WILL LIKELY BE NEEDED. WILL PASS THIS ONTO THE
DAYSHIFT AS WELL FOR FURTHER ASSESSMENT.
FRIDAY NIGHT THROUGH SATURDAY LOOKS DRY WITH HIGH PRESSURE MOVING
IN.
PRECIPITATION CHANCES WILL RETURN SATURDAY NIGHT THROUGH MONDAY AS
LOW PRESSURE MOVES ACROSS THE NORTHERN PLAINS INTO THE UPPER
MISSISSIPPI RIVER VALLEY REGION.
OTHERWISE...LOOK FOR BELOW NORMAL TEMPERATURES TO CONTINUE THROUGH
THE WEEKEND...POSSIBLY GETTING TO NEAR NORMAL BY MONDAY.
&&
.AVIATION...THROUGH 18Z WEDNESDAY
1208 PM CDT TUE APR 16 2013
MVFR CLOUDS TO SLOWLY CLEAR THIS AFTERNOON AND GIVE WAY TO VFR
CONDITIONS UNTIL A MAJOR WEATHER SYSTEM MOVES IN FOR WEDNESDAY AND
THURSDAY.
MOISTURE WILL INCREASE SUBSTANTIALLY IN THE ATMOSPHERE OVER THE
TAF SITES WEDNESDAY MORNING WITH DETERIORATING CONDITIONS EXPECTED
THROUGH THE DAY IN -RA/RA. PERIODIC IFR CIGS/VSBYS ARE POSSIBLE
LATER WEDNESDAY AND INTO THURSDAY. THUS...CONDITIONS WILL BE BEST
FOR AVIATION USERS IN THE MORNING WEDNESDAY.
A CHANGE TO ACCUMULATING SNOW WILL OCCUR THURSDAY NIGHT AT KRST
AND IFR CONDITIONS LOOK LIKELY INTO FRIDAY.
&&
.HYDROLOGY...MAINLY WEDNESDAY AND WEDNESDAY NIGHT
ISSUED AT 354 AM CDT TUE APR 16 2013
ADDITIONAL RAINFALL WED/WED NIGHT/THU POSES A FLOODING THREAT FOR
MOST IF NOT ALL RIVERS AND STREAMS IN OUR FORECAST AREA. RUNOFF FROM
EXPECTED 1.5 TO 3.5 INCHES OF RAINFALL FROM WED THROUGH THU WILL
LIKELY PRODUCE ADDITIONAL RISES ON THE TRIBUTARY RIVERS/ STREAMS
THAT ARE ALREADY RUNNING HIGH FROM RECENT RAINFALL AND SNOW MELT
THIS PAST WEEK. GIVEN THIS EXPECTED RAINFALL ALONG WITH LOCALIZED
HIGHER RAINFALL RATES...ADDITIONAL FLOODING IS POSSIBLE IF NOT
LIKELY ON THE TRIBUTARY RIVERS LATER IN THE WEEK INTO THE WEEKEND.
WILL CONTINUE HYDROLOGIC OUTLOOK PRODUCT ADDRESSING THE
RAIN/FLOODING THREATS LATER IN THE WEEK.
LOOK FOR WATER LEVELS ON THE MISSISSIPPI RIVER TO REMAIN NEARLY
STEADY OR GRADUALLY RISE THIS WEEK AS RUNOFF FROM RECENT RAINS AND
SNOWMELT MOVES DOWNSTREAM. THE ADDITIONAL RAINS ON WEDNESDAY THROUGH
THURSDAY WOULD CREATE ADDITIONAL RISES ON THE MISSISSIPPI
RIVER...BUT MOST OF THESE RISES FROM THE WED-THU RAINS EXPECTED NOT
TO SHOW UP IN THE MISSISSIPPI RIVER UNTIL EARLY NEXT WEEK.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1208 PM CDT TUE APR 16 2013
WI...FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE THURSDAY NIGHT
FOR WIZ017-029-032>034-041>044-053>055-061.
MN...FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE THURSDAY NIGHT
FOR MNZ079-086>088-094>096.
IA...FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE THURSDAY NIGHT
FOR IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...BAUMGARDT
HYDROLOGY....DAS/RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
629 AM CDT TUE APR 16 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 354 AM CDT TUE APR 16 2013
WATER VAPOR IMAGERY AND RAP 500MB ANALYSIS SHOWS A BROAD/RELATIVELY
DEEP UPPER TROUGH AXIS SITUATED OVER THE WEST COAST/INTERMOUNTAIN
REGION. SOUTHWEST FLOW ALOFT OUT F THIS TROUGH WAS SPILLING QUITE A
BIT OF MID/HIGH CLOUD INTO THE REGION. AT THE SURFACE...THE FORECAST
AREA WAS STILL UNDER THE INFLUENCE OF THE LOW PRESSURE THAT BROUGHT
A WINTRY MIX/RAINFALL INTO THE AREA OVER THE WEEKEND. CYCLONIC FLOW
AROUND THE LOW OVER SOUTHERN ONTARIO WAS PRODUCING AN EXTENSIVE
STRATOCUMULUS FILED ACROSS NORTHERN MN INTO NORTHER WI.
OTHERWISE...TEMPERATURES AT 3 AM WERE IN THE 30S.
MAIN FORECAST CHALLENGE IN THE SHORT TERM WILL BE CLOUDS AND
TEMPERATURES THROUGH TONIGHT.
16.00Z NCEP MODEL SUITE AS WELL AS THE ECMWF AND GEM ALL IN GOOD
AGREEMENT IN THE SHORT TERM.
FOR TODAY...WILL SEE THE LOW OVER ONTARIO LIFT FARTHER EAST INTO
QUEBEC...WITH HIGH PRESSURE BUILDING IN FROM THE NORTHERN PLAINS.
THIS WILL KEEP US DRY...BUT SOUTHWEST FLOW ALOFT WILL CONTINUE TO
SPILL MID/HIGH CLOUD INTO THE REGION. NOT TOO CONFIDENT HOW THICK
THIS CLOUD COVER WILL BE. BUFKIT SHOWS ALTERNATE THICKENING/THINNING
THROUGH THE DAY. FEEL WE SEE SOMEWHERE BETWEEN 40-60 PERCENT
OPAQUENESS FOR PARTLY TO MOSTLY SUNNY CONDITIONS. TEMPERATURES TODAY
EXPECTED TO TOP OFF IN THE MIDDLE 40S ACROSS NORTH CENTRAL WI...TO
THE LOWER 50S ACROSS PORTIONS OF NORTHEAST IOWA INTO SOUTHWEST WI.
CLOUDS WILL THEN THICKEN TONIGHT AHEAD OF FAIRLY STRONG CYCLOGENESIS
EAST OF THE COLORADO ROCKY MOUNTAIN FRONT WITH INCREASING MOISTURE
TRANSPORT AND ISENTROPIC LIFT. MOISTURE WILL BE BATTLING DRY AIR
INITIALLY...BUT FEEL SOME RAIN WILL BE POSSIBLE ACROSS NORTHEAST
IA/SOUTHEAST MN/FAR SOUTHWEST WI TOWARD MORNING. OTHERWISE...WITH
THICKENING CLOUDS...LOOK FOR TEMPERATURES TO RANGE FROM NEAR 30
ACROSS NORTH CENTRAL WI...TO THE MIDDLE AND UPPER 30S ACROSS
NORTHEAST IA INTO SOUTHWEST WI.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 354 AM CDT TUE APR 16 2013
LOOK FOR RAIN TO OVERSPREAD THE AREA ON WEDNESDAY AS STRONG LOW
PRESSURE MOVING OUT INTO THE PLAINS INCREASES MOISTURE TRANSPORT
INTO THE AREA. NAM ALSO INDICATING SOME ELEVATED MUCAPE OF A COUPLE
HUNDRED J/KG GOING INTO THE AFTER NOON FOR PERHAPS A CLAP OR TWO OF
THUNDER.
RAINFALL EXPECTED TO REALLY PICK UP OVER THE AREA WEDNESDAY
AFTERNOON/NIGHT AS THE LOW MOVES FROM MO INTO SOUTHEAST WI. SREF
INDICATING INCREASING 850-700MB FRONTOGENESIS OVER THE FORECAST AREA
NORTHWEST OF THE LOW ALONG WITH INCREASING MOISTURE TRANSPORT...
WITH PRECIPITABLE WATERS MOVING INTO THE 1-1.5 INCH RANGE. RAIN
RATES COULD GET MODERATE TO HEAVY AT TIMES GIVEN THIS SCENARIO. RAIN
THEN EXPECTED TO TAPER OFF ON THURSDAY AS THE LOW PULLS INTO LOWER
MI. THINKING THAT FOCUSED FORCING ALONG WITH MUCH HIGHER THAN NORMAL
PRECIPITABLE WATER VALUES WILL YIELD RAINFALL AMOUNTS SOMEWHERE IN
THE 1.5-3.5 INCH RANGE WITH A FEW LOCALLY HIGHER AMOUNTS GIVEN THE
EMBEDDED THUNDERSTORM POTENTIAL. HYDROLOGY EXPECTED TO BECOME AN
ISSUE ONCE AGAIN WITH RIVERS RUNNING FAIRLY HIGH RIGHT NOW. MORE ON
THIS IS COVERED IN THE HYDROLOGY SECTION BELOW. CONCERN IS
INCREASING THAT A FLOOD WATCH MAY BECOME NECESSARY AS WELL WITH
SATURATED GROUND AND POTENTIAL FOR OVERLAND FLOODING IN ADDITION TO
RIVER FLOODING SINCE OUR 6-HRLY FLASH FLOOD GUIDANCE IS ONLY RUNNING
2-3 INCHES. WILL HAVE THE DAY SHIFT ASSESS THIS WITH THE 12Z MODEL
RUNS.
ATTENTION THEN TURNS TO SIGNIFICANT SNOWFALL POTENTIAL FOR THURSDAY
NIGHT INTO FRIDAY. MODELS ARE BECOMING MORE IN AGREEMENT AND
CONSISTENT WITH INCREASING SNOW SIGNAL FOR THE AREA. ECMWF/GFS/GEM
ALL BRING ANOTHER WAVE OF LOW PRESSURE UP ALONG THE EXISTING
BAROCLINIC ZONE AS A VIGOROUS MID-LEVEL TROUGH/CLOSED LOW MOVES
TOWARD THE AREA FROM THE PLAINS. STRONG DEFORMATION ZONE THEN SETS
UP ACROSS THE NORTHWEST HALF OF THE FORECAST AREA. LATEST GFS COB
WANTS TO PRODUCE 8+ INCHES/LOCALLY HIGHER AMOUNTS NORTHWEST OF A
LINE ROUGHLY RUNNING FROM MEDFORD AND LA CROSSE WI...TO NEAR OELWEIN
IA. HEADLINES WILL LIKELY BE NEEDED. WILL PASS THIS ONTO THE
DAYSHIFT AS WELL FOR FURTHER ASSESSMENT.
FRIDAY NIGHT THROUGH SATURDAY LOOKS DRY WITH HIGH PRESSURE MOVING
IN.
PRECIPITATION CHANCES WILL RETURN SATURDAY NIGHT THROUGH MONDAY AS
LOW PRESSURE MOVES ACROSS THE NORTHERN PLAINS INTO THE UPPER
MISSISSIPPI RIVER VALLEY REGION.
OTHERWISE...LOOK FOR BELOW NORMAL TEMPERATURES TO CONTINUE THROUGH
THE WEEKEND...POSSIBLY GETTING TO NEAR NORMAL BY MONDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 629 AM CDT TUE APR 16 2013
AN AREA OF STRATUS GENERALLY NORTH OF INTERSTATE 90 WAS SLOWLY
SAGGING SOUTHWARD. RAP AND NAM BUFKIT SOUNDINGS INDICATE THESE
SHOULD MIX OUT BY MID TO LATE MORNING WITH VFR CONDITIONS AFTER
THAT. MOISTURE TRANSPORT WILL INCREASE LATE TONIGHT AHEAD OF A
DEVELOPING STORMS SYSTEM OVER THE PLAINS. THIS WILL SPREAD A MID
DECK OF CLOUDS INTO THE TAF SITES...BUT ANY PRECIPITATION SHOULD
HOLD OFF UNTIL AFTER 12Z.
&&
.HYDROLOGY...MAINLY WEDNESDAY AND WEDNESDAY NIGHT
ISSUED AT 354 AM CDT TUE APR 16 2013
ADDITIONAL RAINFALL WED/WED NIGHT/THU POSES A FLOODING THREAT FOR
MOST IF NOT ALL RIVERS AND STREAMS IN OUR FORECAST AREA. RUNOFF FROM
EXPECTED 1.5 TO 3.5 INCHES OF RAINFALL FROM WED THROUGH THU WILL
LIKELY PRODUCE ADDITIONAL RISES ON THE TRIBUTARY RIVERS/ STREAMS
THAT ARE ALREADY RUNNING HIGH FROM RECENT RAINFALL AND SNOW MELT
THIS PAST WEEK. GIVEN THIS EXPECTED RAINFALL ALONG WITH LOCALIZED
HIGHER RAINFALL RATES...ADDITIONAL FLOODING IS POSSIBLE IF NOT
LIKELY ON THE TRIBUTARY RIVERS LATER IN THE WEEK INTO THE WEEKEND.
WILL CONTINUE HYDROLOGIC OUTLOOK PRODUCT ADDRESSING THE
RAIN/FLOODING THREATS LATER IN THE WEEK.
LOOK FOR WATER LEVELS ON THE MISSISSIPPI RIVER TO REMAIN NEARLY
STEADY OR GRADUALLY RISE THIS WEEK AS RUNOFF FROM RECENT RAINS AND
SNOWMELT MOVES DOWNSTREAM. THE ADDITIONAL RAINS ON WEDNESDAY THROUGH
THURSDAY WOULD CREATE ADDITIONAL RISES ON THE MISSISSIPPI
RIVER...BUT MOST OF THESE RISES FROM THE WED-THU RAINS EXPECTED NOT
TO SHOW UP IN THE MISSISSIPPI RIVER UNTIL EARLY NEXT WEEK.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...RABERDING
HYDROLOGY....DAS/RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
354 AM CDT TUE APR 16 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 354 AM CDT TUE APR 16 2013
WATER VAPOR IMAGERY AND RAP 500MB ANALYSIS SHOWS A BROAD/RELATIVELY
DEEP UPPER TROUGH AXIS SITUATED OVER THE WEST COAST/INTERMOUNTAIN
REGION. SOUTHWEST FLOW ALOFT OUT F THIS TROUGH WAS SPILLING QUITE A
BIT OF MID/HIGH CLOUD INTO THE REGION. AT THE SURFACE...THE FORECAST
AREA WAS STILL UNDER THE INFLUENCE OF THE LOW PRESSURE THAT BROUGHT
A WINTRY MIX/RAINFALL INTO THE AREA OVER THE WEEKEND. CYCLONIC FLOW
AROUND THE LOW OVER SOUTHERN ONTARIO WAS PRODUCING AN EXTENSIVE
STRATOCUMULUS FILED ACROSS NORTHERN MN INTO NORTHER WI.
OTHERWISE...TEMPERATURES AT 3 AM WERE IN THE 30S.
MAIN FORECAST CHALLENGE IN THE SHORT TERM WILL BE CLOUDS AND
TEMPERATURES THROUGH TONIGHT.
16.00Z NCEP MODEL SUITE AS WELL AS THE ECMWF AND GEM ALL IN GOOD
AGREEMENT IN THE SHORT TERM.
FOR TODAY...WILL SEE THE LOW OVER ONTARIO LIFT FARTHER EAST INTO
QUEBEC...WITH HIGH PRESSURE BUILDING IN FROM THE NORTHERN PLAINS.
THIS WILL KEEP US DRY...BUT SOUTHWEST FLOW ALOFT WILL CONTINUE TO
SPILL MID/HIGH CLOUD INTO THE REGION. NOT TOO CONFIDENT HOW THICK
THIS CLOUD COVER WILL BE. BUFKIT SHOWS ALTERNATE THICKENING/THINNING
THROUGH THE DAY. FEEL WE SEE SOMEWHERE BETWEEN 40-60 PERCENT
OPAQUENESS FOR PARTLY TO MOSTLY SUNNY CONDITIONS. TEMPERATURES TODAY
EXPECTED TO TOP OFF IN THE MIDDLE 40S ACROSS NORTH CENTRAL WI...TO
THE LOWER 50S ACROSS PORTIONS OF NORTHEAST IOWA INTO SOUTHWEST WI.
CLOUDS WILL THEN THICKEN TONIGHT AHEAD OF FAIRLY STRONG CYCLOGENESIS
EAST OF THE COLORADO ROCKY MOUNTAIN FRONT WITH INCREASING MOISTURE
TRANSPORT AND ISENTROPIC LIFT. MOISTURE WILL BE BATTLING DRY AIR
INITIALLY...BUT FEEL SOME RAIN WILL BE POSSIBLE ACROSS NORTHEAST
IA/SOUTHEAST MN/FAR SOUTHWEST WI TOWARD MORNING. OTHERWISE...WITH
THICKENING CLOUDS...LOOK FOR TEMPERATURES TO RANGE FROM NEAR 30
ACROSS NORTH CENTRAL WI...TO THE MIDDLE AND UPPER 30S ACROSS
NORTHEAST IA INTO SOUTHWEST WI.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 354 AM CDT TUE APR 16 2013
LOOK FOR RAIN TO OVERSPREAD THE AREA ON WEDNESDAY AS STRONG LOW
PRESSURE MOVING OUT INTO THE PLAINS INCREASES MOISTURE TRANSPORT
INTO THE AREA. NAM ALSO INDICATING SOME ELEVATED MUCAPE OF A COUPLE
HUNDRED J/KG GOING INTO THE AFTER NOON FOR PERHAPS A CLAP OR TWO OF
THUNDER.
RAINFALL EXPECTED TO REALLY PICK UP OVER THE AREA WEDNESDAY
AFTERNOON/NIGHT AS THE LOW MOVES FROM MO INTO SOUTHEAST WI. SREF
INDICATING INCREASING 850-700MB FRONTOGENESIS OVER THE FORECAST AREA
NORTHWEST OF THE LOW ALONG WITH INCREASING MOISTURE TRANSPORT...
WITH PRECIPITABLE WATERS MOVING INTO THE 1-1.5 INCH RANGE. RAIN
RATES COULD GET MODERATE TO HEAVY AT TIMES GIVEN THIS SCENARIO. RAIN
THEN EXPECTED TO TAPER OFF ON THURSDAY AS THE LOW PULLS INTO LOWER
MI. THINKING THAT FOCUSED FORCING ALONG WITH MUCH HIGHER THAN NORMAL
PRECIPITABLE WATER VALUES WILL YIELD RAINFALL AMOUNTS SOMEWHERE IN
THE 1.5-3.5 INCH RANGE WITH A FEW LOCALLY HIGHER AMOUNTS GIVEN THE
EMBEDDED THUNDERSTORM POTENTIAL. HYDROLOGY EXPECTED TO BECOME AN
ISSUE ONCE AGAIN WITH RIVERS RUNNING FAIRLY HIGH RIGHT NOW. MORE ON
THIS IS COVERED IN THE HYDROLOGY SECTION BELOW. CONCERN IS
INCREASING THAT A FLOOD WATCH MAY BECOME NECESSARY AS WELL WITH
SATURATED GROUND AND POTENTIAL FOR OVERLAND FLOODING IN ADDITION TO
RIVER FLOODING SINCE OUR 6-HRLY FLASH FLOOD GUIDANCE IS ONLY RUNNING
2-3 INCHES. WILL HAVE THE DAY SHIFT ASSESS THIS WITH THE 12Z MODEL
RUNS.
ATTENTION THEN TURNS TO SIGNIFICANT SNOWFALL POTENTIAL FOR THURSDAY
NIGHT INTO FRIDAY. MODELS ARE BECOMING MORE IN AGREEMENT AND
CONSISTENT WITH INCREASING SNOW SIGNAL FOR THE AREA. ECMWF/GFS/GEM
ALL BRING ANOTHER WAVE OF LOW PRESSURE UP ALONG THE EXISTING
BAROCLINIC ZONE AS A VIGOROUS MID-LEVEL TROUGH/CLOSED LOW MOVES
TOWARD THE AREA FROM THE PLAINS. STRONG DEFORMATION ZONE THEN SETS
UP ACROSS THE NORTHWEST HALF OF THE FORECAST AREA. LATEST GFS COB
WANTS TO PRODUCE 8+ INCHES/LOCALLY HIGHER AMOUNTS NORTHWEST OF A
LINE ROUGHLY RUNNING FROM MEDFORD AND LA CROSSE WI...TO NEAR OELWEIN
IA. HEADLINES WILL LIKELY BE NEEDED. WILL PASS THIS ONTO THE
DAYSHIFT AS WELL FOR FURTHER ASSESSMENT.
FRIDAY NIGHT THROUGH SATURDAY LOOKS DRY WITH HIGH PRESSURE MOVING
IN.
PRECIPITATION CHANCES WILL RETURN SATURDAY NIGHT THROUGH MONDAY AS
LOW PRESSURE MOVES ACROSS THE NORTHERN PLAINS INTO THE UPPER
MISSISSIPPI RIVER VALLEY REGION.
OTHERWISE...LOOK FOR BELOW NORMAL TEMPERATURES TO CONTINUE THROUGH
THE WEEKEND...POSSIBLY GETTING TO NEAR NORMAL BY MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1145 PM CDT MON APR 15 2013
THE AREA OF LOW PRESSURE AT THE SURFACE HAS MOVED NORTHEAST INTO
ONTARIO THIS EVENING. THIS HAS ALLOWED THE CYCLONIC FLOW TO RELAX
ENOUGH FOR THE WINDS TO DROP DOWN TO ABOUT 10 KNOTS. THE WINDS ARE
EXPECTED TO REMAIN AT THIS SPEED THROUGH MUCH OF TUESDAY BEFORE
TURNING MORE TO THE NORTHEAST AS WEAK HIGH PRESSURE MOVES BY TO
THE NORTH. ENOUGH DRY AIR HAS BEEN PULLED IN TO ALLOW THE LOW AND
MID LEVEL CLOUDS TO DISSIPATE LEAVING JUST SOME OCCASIONAL HIGH
CLOUDS TO COME IN FROM THE SOUTHWEST. WILL SEE VFR CONDITIONS
THROUGH THE PERIOD...BUT MOISTURE FROM THE NEXT SYSTEM WILL BRING
IN A CEILING AROUND 10K FEET LATE TUESDAY AFTERNOON OR EVENING
WITH THIS GRADUALLY LOWERING THROUGH THE EVENING.
&&
.HYDROLOGY...MAINLY WEDNESDAY AND WEDNESDAY NIGHT
ISSUED AT 354 AM CDT TUE APR 16 2013
ADDITIONAL RAINFALL WED/WED NIGHT/THU POSES A FLOODING THREAT FOR
MOST IF NOT ALL RIVERS AND STREAMS IN OUR FORECAST AREA. RUNOFF FROM
EXPECTED 1.5 TO 3.5 INCHES OF RAINFALL FROM WED THROUGH THU WILL
LIKELY PRODUCE ADDITIONAL RISES ON THE TRIBUTARY RIVERS/ STREAMS
THAT ARE ALREADY RUNNING HIGH FROM RECENT RAINFALL AND SNOW MELT
THIS PAST WEEK. GIVEN THIS EXPECTED RAINFALL ALONG WITH LOCALIZED
HIGHER RAINFALL RATES...ADDITIONAL FLOODING IS POSSIBLE IF NOT
LIKELY ON THE TRIBUTARY RIVERS LATER IN THE WEEK INTO THE WEEKEND.
WILL CONTINUE HYDROLOGIC OUTLOOK PRODUCT ADDRESSING THE
RAIN/FLOODING THREATS LATER IN THE WEEK.
LOOK FOR WATER LEVELS ON THE MISSISSIPPI RIVER TO REMAIN NEARLY
STEADY OR GRADUALLY RISE THIS WEEK AS RUNOFF FROM RECENT RAINS AND
SNOWMELT MOVES DOWNSTREAM. THE ADDITIONAL RAINS ON WEDNESDAY THROUGH
THURSDAY WOULD CREATE ADDITIONAL RISES ON THE MISSISSIPPI
RIVER...BUT MOST OF THESE RISES FROM THE WED-THU RAINS EXPECTED NOT
TO SHOW UP IN THE MISSISSIPPI RIVER UNTIL EARLY NEXT WEEK.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...04
HYDROLOGY....DAS/RRS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
240 AM CDT THU APR 18 2013
.MESOSCALE DISCUSSION FOR HEAVY RAIN...
235 AM CDT
A CONTINUED TEXTBOOK SETUP FOR HEAVY RAIN REMAINS IN PLACE EARLY
THIS MORNING AND WILL THROUGH LATE MORNING ACROSS THE FORECAST
AREA...WITH SIGNIFICANT...EVEN RECORD RIVER FLOODING...A RESPONSE
OVER THE NEXT COUPLE DAYS. WHILE AREAL FLOODING REPORTS HAVE
BECOME A MORE FAR AND FEW BETWEEN VERY EARLY THIS MORNING...ONLY
PART OF THAT IS LIKELY DUE TO A TEMPORARY EASE IN RAINFALL RATES
AND MORE OF IT DUE TO THE FACT IT IS DARK OUTSIDE. RAINFALL
AMOUNTS ESTIMATED BY RADAR OR OBSERVED THROUGH 1 AM THURSDAY ARE
BETWEEN ONE AND A HALF TO FOUR INCHES....WITH THE HIGHEST AMOUNTS
IN NORTHWEST LIVINGSTON COUNTY...THE PANHANDLE OF LASALLE
COUNTY...AND WESTERN LEE AND OGLE COUNTIES.
THE ELEVATED STATIONARY FRONT IS PARKED DIRECTLY OVER THE CWA WITH
CONTINUOUS -70C CLOUD TOPS AND ASSOCIATED DEEP CONVECTION TRAINING
ENE. IMPRESSIVE LOW-LEVEL CONVERGENCE IS FOCUSED ALONG THIS
BOUNDARY AS JUST INFERRED BY THE VAD WIND PROFILER ANALYSIS EARLY
THIS MORNING...WITH 70 KTS OF SOUTHERLY 850MB FLOW OVER LSX AND
ILX...25 KTS AT LOT...AND NORTHERLY FLOW AT DVN AND MKX. THE
REPLENISHMENT OF MOISTURE ON THIS LOW-LEVEL JET IS EXTREME...WITH
MOISTURE TRANSPORT MAGNITUDES VERY HIGH. AMBIENT MOISTURE VALUES
ARE ALSO PRACTICALLY OFF THE CHARTS...WITH PWAT VALUES RIGHT AT
AND POSSIBLY OVER RECORD APRIL LEVELS BASED ON THE HISTORICAL RAOB
RECORDS. A TONGUE OF 4C AND HIGHER DEW POINTS AT 700MB ON LAST
EVES RAOBS AND CONTINUED TO BE ANALYZED ARE DIRECTED RIGHT INTO
THE AREA...WHICH ARE AT LEVELS SHOWN TO REFLECT WARM SEASON RAIN
PROCESSES. REFLECTIVITY SINCE MIDNIGHT HAS LOST SOME OF ITS
ORGANIZED EMBEDDED STORMS...HOWEVER THE AMOUNT OF 40+ DBZ REMAINS
HIGH ALONG WITH LIGHTNING...BOTH REFLECTIVE OF HEAVIER RAINFALL
RATES. AGAIN...CONTENT/CONCENTRATION...REPLENISHMENT...AND
FOCUS/POOLING OF HEAVY RAINFALL PARAMETERS ARE ALL IN PLACE.
LOOKING FORWARD THROUGH 10 AM...THESE PARAMETERS ALMOST ENTIRELY
REMAIN IN PLACE. WITH SIX HOUR FLOOD GUIDANCE BEING APPROACHED AND
MORE OF THE WATER TURNING INTO RUNOFF IMMEDIATELY...THIS IS LIKELY
IN ITSELF TO CAUSE FLOODING ISSUES. WHILE THE BOUNDARY HAS TRIED
TO INCH NORTHWARD AND THAT HAS BEEN SEEN SLIGHTLY IN THE RAIN
PLACEMENT...AN APPROACHING DEEP SHORT WAVE FROM WESTERN MO WILL
LIKELY CONTINUE TO BLOSSOM CONVECTION ACROSS WESTERN IL INTO THE
FORECAST AREA. SO AN UPTICK IN CONVECTION IS PROBABLE...AND THUS
EVEN SOME HEAVIER RAINFALL RATES FOR A PERIOD. THIS IS MOST
FAVORED SOUTH OF INTERSTATE 88 ON CONVECTIVE ALLOWING MODELS. HAVE
GONE WITH FLOOD WARNINGS BUT FLASH FLOODING AS THIS PASSES ACROSS
MAY BE SEEN...ESPECIALLY IN PARTS OF LA SALLE AND LIVINGSTON
COUNTIES...AS WELL AS ANY URBAN AREAS IMPACTED.
MTF
&&
.DISCUSSION...
934 PM CDT
EVENING/MESOSCALE UPDATE...
HAVE CANCELLED REMAINING CONVECTIVE WATCHES...THOUGH FLOODING WILL
CONTINUE TO BE A SIGNIFICANT ISSUE THROUGH THURSDAY AND BEYOND.
WARM FRONT EXTENDS FROM LOW PRESSURE WAVE OVER WESTERN MISSOURI...
NORTHEAST INTO CENTRAL ILLINOIS AND CENTRAL INDIANA AT 02Z. OUTFLOW
FROM PERSISTENT ELEVATED THUNDERSTORMS ACROSS IA/NORTHERN IL/IN HAS
CONTINUED TO SUPPRESS SURFACE WARM FRONT SOUTH OF THE CWA...AND WILL
LIKELY CONTINUE TO DO SO OVERNIGHT BEFORE DEEPENING SURFACE LOW
LIFTS FROM MISSOURI INTO NORTHWEST IL IN ASSOCIATION WITH SHORT WAVE
LIFTING OUT OF BASE OF UPPER TROUGH OVER THE SOUTHERN PLAINS.
UNFORTUNATELY...THIS WILL RESULT IN CONTINUED FORCED ASCENT ATOP
CONVECTIVELY ENHANCED FRONTAL ZONE TONIGHT WITHIN A BROAD REGION OF
PERSISTENT STRONG WARM/MOIST ADVECTION AHEAD OF DEEP UPPER TROUGH
OVER THE PLAINS.
ILX 00Z SOUNDING TELLS THE STORY WITH RESPECT TO THE DIMINISHED
SEVERE THREAT WITH STRONG LOW LEVEL INVERSION NORTH OF FRONT
PREVENTING NEAR SFC-BASED STORMS. RAP GUIDANCE CONTINUES TO DEPICT A
GRADIENT IN THE MUCAPE FIELD INCREASING TO 500-1000 J/KG AS YOU MOVE
FARTHER SOUTH OF I-80. WHILE EFFECTIVE BULK SHEAR IN EXCESS OF 60 KT
WILL CONTINUE TO ALLOW SOME ORGANIZATION FOR ELEVATED CONVECTION
NORTH OF WARM FRONT...THE THREAT OF SEVERE WEATHER SHOULD BE
LIMITED TO MARGINAL HAIL WITH THE BETTER ORGANIZED STORMS.
WHILE THE SEVERE THREAT INTO THE OVERNIGHT HOURS IS RATHER LOW...
FLOODING THREAT CONTINUES TO BE SIGNIFICANT INTO THURSDAY. RADAR
ESTIMATES AND OBSERVED RAINFALL REPORTS INDICATE THAT MOST AREAS
HAVE SEEN UPWARDS OF 0.75 INCHES OF RAIN...WITH MANY AREAS BETWEEN
1.5 AND 2.0 INCHES AND PARTS OF NORTH CENTRAL ILLINOIS IN EXCESS OF
2.5 INCHES. ILX 00Z RAOB DEPICTS PWAT OF 1.38 INCHES...199 PERCENT
OF NORMAL...AN INDICATION OF THE VERY MOIST AIR MASS. ADDITIONAL
RAINFALL AMOUNTS IN THE 1-2 INCH RANGE ARE VERY LIKELY THROUGH
THURSDAY...LIKELY LEADING TO EXTENSIVE FLOODING ON AREA STREAMS AND
RIVERS. AERIAL FLOOD WARNINGS REMAIN IN EFFECT INTO MIDDAY
THURSDAY...AND MANY RIVER FORECAST SITES ARE HEADED FOR MODERATE TO
MAJOR FLOODING.
RATZER
//PREV DISCUSSION...
342 PM CDT
.SHORT TERM...THROUGH FRIDAY...
HAZARDOUS WEATHER ISSUES FROM SEVERE THUNDERSTORMS TO EXCESSIVE
RAINFALL TO TORNADIC POTENTIAL WILL IMPACT THE REGION THROUGH
THURSDAY NIGHT.
FOR THE REMAINDER OF THE AFTERNOON AND INTO THIS EVENING...AT 230PM
CDT...STRONG THUNDERSTORMS EXTEND ALONG A LINE FROM NEAR
WAUKEGAN...SOUTHWEST THROUGH OTTAWA. WEST OF THIS LINE...AN
EXTENSIVE AREA OF OVERRUNNING PCPN WITH EMBEDDED THUNDER EXTENDED
BACK THROUGH ERN IOWA AND MISSOURI. MUCH OF THE ACTIVITY OVER NRN
IL HAS FORMED ALONG AN ELEVATED WARM FRONT...BUT A MORE SOLID LINE
HAS DEVELOPED IN THE WARM SECTOR. EXPECT THAT THE THUNDERSTORMS
WILL SAG SEWD THROUGH THE EVENING...BRINGING SHOWERS AND
THUNDERSTORMS INTO EAST-CENTRAL ILLINOIS AND NORTHWESTERN INDIANA.
WITH COPIOUS AMOUNTS OF MOISTURE STREAMING INTO THE REGION...THE
STORMS HAVE BEEN VERY EFFICIENT RAIN PRODUCERS...WITH 0.81 INCHES OF
RAIN MEASURED AT THE ROCKFORD AIRPORT BTWN 12-18Z THIS MORNING.
STORMS HAVE ALSO BEEN MARGINALLY SEVERE WITH NUMEROUS REPORTS OF
SMALL HAIL RECEIVED...AND A FEW REPORTS OF LARGER HAIL AS WELL.
THIS WILL BE THE CONVECTIVE MODE FOR THE REMAINDER OF THE EVENING
AND OVERNIGHT TONIGHT...WITH MODERATE TO HEAVY RAIN AND SMALL HAIL
AND OCCASIONAL STRONG WINDS GUSTS.
THE FLOODING AND SEVERE WEATHER POTENTIAL WILL RAMP UP EVEN FURTHER
TOMORROW AS THE UPPER TROUGH MOVES OUT OVER THE CENTRAL PLAINS AND A
SFC LOW DEEPENS. THE SFC LOW WILL SWING THROUGH THE SOUTH HIGH
PLAINS EARLY THIS EVENING BEFORE TURNING NEWD...RIPPLING ALONG A
QUASI-STATIONARY COLD FRONT AND WARM FRONT. BY THURSDAY
MORNING...THE LOW WILL ELONGATE FROM NWRN IL THROUGH NWRN MO...WITH
THE SFC WARM FRONT EXTENDING NEWD ACROSS CENTRAL LAKE MICHIGAN.
THIS WILL PUT THE CWA FIRMLY IN THE WARM SECTOR. WITH A WIDE OPEN
GLFMEX...DEEP LAYER MOISTURE WILL STREAM NWD INTO THE REGION...WITH
PWATS EXCEEDING 1.5 INCHES FOR AN EXTENDED PERIOD OF TIME...LEADING
TO THE POTENTIAL FOR SIGNIFICANT WIDESPREAD RIVER AND AREAL
FLOODING. SEE THE HYDROLOGY SECTION FOR FURTHER DETAILS.
THE SEVERE WEATHER MODE SHOULD FOCUS ON STRONG...DAMAGING WINDS AND
POSSIBLE TORNADOES. THE LATEST SPC DAY 2 CONVECTIVE OUTLOOK HAS
INCREASED THE AREA SOUTH OF A LINE FROM EVANSTON TO PONTIAC TO A
MODERATE RISK...WITH THE REMAINDER OF THE AREA IN A SLIGHT RISK.
INCREASING HEAT AND MOISTURE...TEMPERATURES REACHING INTO THE LOW TO
MIDDLE 70S AND DEW POINTS IN THE LOW TO MIDDLE 60S IN THE WARM
SECTOR...INSTABILITY WILL BE AMPLE. WHILE THE GENERAL CONVECTIVE
MODE WILL BE LINEAR WITH SMALL LINES AND BOWS POSSIBLE...PRODUCING
DAMAGING WINDS...THE MODEL GUIDANCE IS IN GOOD AGREEMENT ON A STRONG
LOW LEVEL JET...WITH SWLY WINDS OF 55-65KT ACROSS THE REGION. WHILE
SFC WINDS ARE GENERALLY PROGGED TO BE SOUTHERLY...THERE WILL BE
OPPORTUNITY FOR SFC WINDS TO BACK A LITTLE MORE EAST OF SOUTH AS THE
SFC LOW TRACKS THROUGH NWRN IL AND INTO SRN WI. GIVEN THE AMPLE
INSTABILITY...COMBINED WITH CLOCKWISE TURNING HODOGRAPHS...DISCRETE
SUPER CELLS MAY DEVELOP OUT IN THE WARM SECTOR AHEAD OF THE LINEAR
CONVECTION...WHICH WOULD BRING THE TORNADIC POTENTIAL TO THE
REGION.
THE POTENTIAL FOR SEVERE WEATHER AND HEAVY RAINFALL WILL CONTINUE
UNTIL THE ASSOCIATED COLD FRONT PUSHES THROUGH THE REGION...BRINGING
IN MUCH COOLER AIR. THE GUIDANCE IS IN GOOD AGREEMENT ON PUSHING
THE FRONT ACROSS THE AREA THURSDAY EVENING. AS THE SFC LOW PUSHES
OFF TO THE NORTHEAST...THE UPPER TROUGH WILL ALSO CROSS THE AREA.
WITH PLENTY OF RESIDUAL SFC MOISTURE AND COOLER AIR AND CYCLONIC
CURVATURE ALOFT...SOME LINGERING INSTABILITY SHOWERS SHOULD PERSIST
INTO FRIDAY. HIGHS ON FRIDAY SHOULD DROP BACK INTO THE MIDDLE TO
UPPER 40S.
KREIN
.LONG TERM - SATURDAY THROUGH WEDNESDAY...
SPRAWLING SURFACE HIGH PRESSURE TO BUILD INTO THE AREA SATURDAY
BEHIND DEPARTING SURFACE LOW/UPPER LEVEL TROUGH. A RETURN TO
UNSEASONABLY COOL TEMPS WITH A NEEDED BREAK IN PRECIPITATION WILL BE
SHORT LIVED HOWEVER AS THE UPPER FLOW QUICKLY RETURNS SOUTHWESTERLY
AS ANOTHER POWERFUL SHORTWAVE TROUGH DIGS INTO WESTERN NORTH AMERICA
ON SUNDAY. THIS SHORTWAVE CARVES OUT A TROUGH ACROSS THE MOUNTAIN
WEST SUNDAY NIGHT INTO MONDAY.
A SERIES OF UPPER LEVEL SHORT WAVE TROUGHS WILL THEN RIPPLE
NORTHEAST IN THE SW FLOW ALOFT. SPECIFIC FEATURES ARE POORLY
RESOLVED BY MEDIUM RANGE MODELS BUT OVERALL TREND WILL BE A RETURN
TO INCREASING MOISTURE AS GULF OPENS BACK UP AGAIN. MEDIUM RANGE
MODELS ARE IN FAIRLY GOOD AGREEMENT IN CONCEPT IN SAGGING THE
SURFACE FRONTAL BOUNDARY SOUTH ACROSS THE LOCAL AREA MONDAY NIGHT
AND STALLING IT OUT TUESDAY SETTING THE STAGE FOR ANOTHER PROLONGED
PERIOD OF WET WEATHER TUESDAY INTO WEDNESDAY AS RIPPLES OF LOW
PRESSURE LIFT NORTHEAST ALONG THE BOUNDARY.
EF
&&
.HYDROLOGY...
350 PM CDT
WITH SFC DEW POINTS EXPECTED TO REACH INTO THE LOWER TO MIDDLE 60S
AND PWATS POSSIBLY REACHING AS HIGH AS 1.75 INCHES...ANY
THUNDERSTORMS THAT DEVELOP WILL BE EFFICIENT RAIN PRODUCERS. BASED
ON THE MATT BUNKERS PWAT CLIMATOLOGY...THESE VALUES APPROACH
RECORD LEVELS. SO...FLOODING WILL BE A MAJOR CONCERN FOR THE
ENTIRE CWA...WITH STORM TOTAL PCPN AMOUNTS OF 2-3 INCHES OVER THE
SERN PORTIONS OF THE CWA...GENERALLY SOUTH OF I-80...AND 3-4
INCHES TO THE NORTH. LATEST LOCAL QPF WOULD SUGGEST AN AREA OF
PCPN OF 4-5 INCHES IS POSSIBLE ALONG OVER NORTHERN ILLINOIS. THIS
REPRESENTS AN INCREASE OVER PREVIOUS FORECASTS...BUT GIVEN THE
RECORD LEVEL PWATS FOR AN EXTENDED PERIOD OF TIME...CONFIDENCE IS
INCREASING FOR THIS SIGNIFICANT RAINFALL. WITH MANY RIVERS AND
STREAMS ARE ALREADY NEAR OR ABOVE MINOR FLOOD STAGE...THIS AMOUNT
OF RAIN WILL BRING ADDITIONAL RISES TO MODERATE AND MAJOR FLOOD
LEVEL. IN ADDITION TO RIVER FLOODING...AREAL FLOODING OR
RURAL...SUBURBAN AND URBAN AREAS IS LIKELY...WITH LOW LYING ROADS
AND VIADUCTS FLOODING...AS WELL AS...ROADSIDE DRAINAGE DITCHES AND
DRAINAGE PONDS EXCEEDING CAPACITY. AREAS NOT SEEING FLOODING WILL
AT LEAST SEE AREAS OF STANDING OR PONDING WATER ON ROADS.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* WIDESPREAD SHRA AND TS TONIGHT.
* PERIODS OF VERY HEAVY RAINFALL THROUGH THE PERIOD...WITH LOW VIS
UNDER 2 MILES AT TIMES.
* LOW LEVEL WIND SHEAR THIS EARLY THIS MORNING WITH A 50 KT
SOUTHERLY JET AT 2,000 FT AGL.
* WINDS SHIFTING OUT OF THE SOUTH AFTER 10 UTC WITH WINDS LIKELY
GUSTING TO 30 TO 35 KT AT TIMES THROUGH MUCH OF THE DAY.
* TIMING OF IMPROVING CONDITIONS BY THIS EVENING.
KJB
//DISCUSSION...UPDATED 06Z...
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO TRAIN NORTHEASTWARD FROM
MISSOURI ACROSS NORTHERN ILLINOIS OVERNIGHT TONIGHT. MOISTURE
TRANSPORT IS ABSOLUTELY IMPRESSIVE...WITH A 50 TO 60KT LOW LEVEL JET
CONTINUALLY PUMPING IN DEEPER MOISTURE. PRECIPITABLE WATER VALUES
ARE PROGGED TO INCREASE TO NEAR 1.6 INCHES WHICH IS NEAR RECORD
VALUES FOR THIS TIME OF YEAR. THE COMBINATION OF THIS DEEP MOISTURE
AND THE THE STRONG DYNAMIC FORCING FROM THIS SYSTEM WILL CONTINUE TO
SUPPORT CONVECTIVE ACTIVITY. THERE COULD BE A VERY SHORT BREAK IN
THE ACTIVITY AROUND DAYBREAK AT THE EASTERN TERMINALS AS THE WARM
FRONT SURGES NORTHWARD THROUGH THE NIGHT. HOWEVER...CONFIDENCE IN THIS
IS LOW.
ANY BREAK IN THE ACTIVITY...WOULD BE SHORT LIVED...AS ADDITIONAL
THUNDERSTORMS WILL MAKE A RETURN BY MID TO LATE MORNING. VERY HEAVY
RAINFALL WILL LIKELY ACCOMPANY THESE THUNDERSTORMS. IT ALSO APPEARS
THAT SEVERAL HOURS OF ADDITIONAL THUNDERSTORM ACTIVITY IS LIKELY
FROM MID TO LATE MORNING THROUGH MUCH OF THE AFTERNOON AS THE CLOUD
BEARING FLOW LOOKS TO REMAIN PARALLEL TO THE APPROACHING SURFACE
BOUNDARY...WHICH SHOULD RESULT IN TRAINING CELLS. THIS HEAVY RAIN
WILL LIKELY REDUCE VISIBILITY UNDER 2 SM AT TIMES...ESPECIALLY
DURING THE AFTERNOON.
WINDS WILL RAPIDLY INCREASE OUT OF THE SOUTH BY EARLY MORNING AS THE
WARM FRONT LIFTS NORTH OF THE AREA. DUE TO THE PRESENCE OF 50 KT OF
FLOW ONLY A COUPLE THOUSAND FEET OFF THE GROUND...SOME OF THIS
MOMENTUM WILL LIKELY BE MIXED TO THE SURFACE. THUS WINDS WILL LIKELY
GUST IN THE LOW TO MID 30 KT RANGE FOR MUCH OF THE DAY. EVEN HIGH
WINDS WILL BE POSSIBLE IN WITHIN THE STRONGER STORMS.
THUNDERSTORM ACTIVITY SHOULD BEGIN TO ABATE ACROSS THE AREA BY LATE
AFTERNOON OR EARLY IN THE EVENING. HOWEVER...THE WINDS WILL SHIFT
OUT OF THE WEST SOUTHWEST BEHIND A COLD FRONT BY MID EVENING. THE
WINDS WILL LIKELY REMAIN GUSTY UP AROUND 30 KT BEHIND THIS
FRONT...BUT THE THREAT FOR THUNDER SHOULD END.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
HIGH CONFIDENCE IN PERIODS OF HEAVY THUNDERSTORM RAIN.
LOW TO MEDIUM CONFIDENCE ON TIMING OF IMPROVING CONDITIONS LATER
TODAY.
MODERATE TO HIGH CONFIDENCE IN WINDS.
HIGH CONFIDENCE IN IFR AND LOWER VIS AND CIGS IN +TSRA ACTIVITY.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...VFR...CHANCE SHRA WITH LOCAL MVFR.
SATURDAY...VFR...LAKE BREEZE DEVELOPING AND REACHING CHI TERMINALS
EARLY-MID AFTERNOON.
SUNDAY...VFR...SLIGHT CHANCE SHRA.
MONDAY...VFR...CHANCE SHOWERS.
TUESDAY...MVFR LOWERING TO IFR....CHANCE OF SHOWERS.
TRS
&&
.MARINE...
420 PM CDT
A PAIR OF LOW PRESSURE CENTERS OVER NORTHERN MISSOURI AND THE
TEXAS PANHANDLE WILL MOVE NORTHEAST TONIGHT AND THURSDAY AND
OVERSPREAD THE GREAT LAKES AREA. A BRIEF PERIOD OF OCCASIONALLY
GALE FORCE GUSTS WILL OCCUR ACROSS SOUTHERN LAKE MICHIGAN
THURSDAY AS THE SURFACE PRESSURE GRADIENT INTENSIFIES SOUTH OF THE
ELONGATED LOW PRESSURE AREA FROM THE SAULT TO GREEN BAY.
AS LOW PRESSURE LOCATES NEAR MILWAUKEE THURSDAY EVENING AND THEN
MOVES NORTHEAST TO THE STRAITS OF MACKINAC BY DAYBREAK FRIDAY... A
POWERFUL COLD FRONT WILL SURGE EAST ACROSS THE LAKE WITH WINDS
INCREASING RAPIDLY BEHIND THE FRONT DURING THE PREDAWN HOURS
FRIDAY. WINDS WILL RAPIDLY REACH GALE FORCE TO 45 KTS FRIDAY WITH
A DIMINISHING TREND BEGINNING AFTER DARK FRIDAY EVENING. SURFACE
HIGH PRESSURE WILL BUILD INTO THE AREA SATURDAY BRINGING A PERIOD
OF LIGHT WINDS LASTING ONLY UNTIL DAYBREAK SUNDAY WHEN SOUTHERLY
FLOW WILL AGAIN INCREASE AHEAD OF AN APPROACHING FRONTAL BOUNDARY.
ED F
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 7 AM FRIDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 AM
FRIDAY.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 AM FRIDAY TO 4 AM
SATURDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742...7 AM THURSDAY TO 7 PM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 7 AM THURSDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...7 AM THURSDAY TO 10 PM
THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
124 AM CDT THU APR 18 2013
.DISCUSSION...
934 PM CDT
EVENING/MESOSCALE UPDATE...
HAVE CANCELLED REMAINING CONVECTIVE WATCHES...THOUGH FLOODING WILL
CONTINUE TO BE A SIGNIFICANT ISSUE THROUGH THURSDAY AND BEYOND.
WARM FRONT EXTENDS FROM LOW PRESSURE WAVE OVER WESTERN MISSOURI...
NORTHEAST INTO CENTRAL ILLINOIS AND CENTRAL INDIANA AT 02Z. OUTFLOW
FROM PERSISTENT ELEVATED THUNDERSTORMS ACROSS IA/NORTHERN IL/IN HAS
CONTINUED TO SUPPRESS SURFACE WARM FRONT SOUTH OF THE CWA...AND WILL
LIKELY CONTINUE TO DO SO OVERNIGHT BEFORE DEEPENING SURFACE LOW
LIFTS FROM MISSOURI INTO NORTHWEST IL IN ASSOCIATION WITH SHORT WAVE
LIFTING OUT OF BASE OF UPPER TROUGH OVER THE SOUTHERN PLAINS.
UNFORTUNATELY...THIS WILL RESULT IN CONTINUED FORCED ASCENT ATOP
CONVECTIVELY ENHANCED FRONTAL ZONE TONIGHT WITHIN A BROAD REGION OF
PERSISTENT STRONG WARM/MOIST ADVECTION AHEAD OF DEEP UPPER TROUGH
OVER THE PLAINS.
ILX 00Z SOUNDING TELLS THE STORY WITH RESPECT TO THE DIMINISHED
SEVERE THREAT WITH STRONG LOW LEVEL INVERSION NORTH OF FRONT
PREVENTING NEAR SFC-BASED STORMS. RAP GUIDANCE CONTINUES TO DEPICT A
GRADIENT IN THE MUCAPE FIELD INCREASING TO 500-1000 J/KG AS YOU MOVE
FARTHER SOUTH OF I-80. WHILE EFFECTIVE BULK SHEAR IN EXCESS OF 60 KT
WILL CONTINUE TO ALLOW SOME ORGANIZATION FOR ELEVATED CONVECTION
NORTH OF WARM FRONT...THE THREAT OF SEVERE WEATHER SHOULD BE
LIMITED TO MARGINAL HAIL WITH THE BETTER ORGANIZED STORMS.
WHILE THE SEVERE THREAT INTO THE OVERNIGHT HOURS IS RATHER LOW...
FLOODING THREAT CONTINUES TO BE SIGNIFICANT INTO THURSDAY. RADAR
ESTIMATES AND OBSERVED RAINFALL REPORTS INDICATE THAT MOST AREAS
HAVE SEEN UPWARDS OF 0.75 INCHES OF RAIN...WITH MANY AREAS BETWEEN
1.5 AND 2.0 INCHES AND PARTS OF NORTH CENTRAL ILLINOIS IN EXCESS OF
2.5 INCHES. ILX 00Z RAOB DEPICTS PWAT OF 1.38 INCHES...199 PERCENT
OF NORMAL...AN INDICATION OF THE VERY MOIST AIR MASS. ADDITIONAL
RAINFALL AMOUNTS IN THE 1-2 INCH RANGE ARE VERY LIKELY THROUGH
THURSDAY...LIKELY LEADING TO EXTENSIVE FLOODING ON AREA STREAMS AND
RIVERS. AERIAL FLOOD WARNINGS REMAIN IN EFFECT INTO MIDDAY
THURSDAY...AND MANY RIVER FORECAST SITES ARE HEADED FOR MODERATE TO
MAJOR FLOODING.
RATZER
//PREV DISCUSSION...
342 PM CDT
.SHORT TERM...THROUGH FRIDAY...
HAZARDOUS WEATHER ISSUES FROM SEVERE THUNDERSTORMS TO EXCESSIVE
RAINFALL TO TORNADIC POTENTIAL WILL IMPACT THE REGION THROUGH
THURSDAY NIGHT.
FOR THE REMAINDER OF THE AFTERNOON AND INTO THIS EVENING...AT 230PM
CDT...STRONG THUNDERSTORMS EXTEND ALONG A LINE FROM NEAR
WAUKEGAN...SOUTHWEST THROUGH OTTAWA. WEST OF THIS LINE...AN
EXTENSIVE AREA OF OVERRUNNING PCPN WITH EMBEDDED THUNDER EXTENDED
BACK THROUGH ERN IOWA AND MISSOURI. MUCH OF THE ACTIVITY OVER NRN
IL HAS FORMED ALONG AN ELEVATED WARM FRONT...BUT A MORE SOLID LINE
HAS DEVELOPED IN THE WARM SECTOR. EXPECT THAT THE THUNDERSTORMS
WILL SAG SEWD THROUGH THE EVENING...BRINGING SHOWERS AND
THUNDERSTORMS INTO EAST-CENTRAL ILLINOIS AND NORTHWESTERN INDIANA.
WITH COPIOUS AMOUNTS OF MOISTURE STREAMING INTO THE REGION...THE
STORMS HAVE BEEN VERY EFFICIENT RAIN PRODUCERS...WITH 0.81 INCHES OF
RAIN MEASURED AT THE ROCKFORD AIRPORT BTWN 12-18Z THIS MORNING.
STORMS HAVE ALSO BEEN MARGINALLY SEVERE WITH NUMEROUS REPORTS OF
SMALL HAIL RECEIVED...AND A FEW REPORTS OF LARGER HAIL AS WELL.
THIS WILL BE THE CONVECTIVE MODE FOR THE REMAINDER OF THE EVENING
AND OVERNIGHT TONIGHT...WITH MODERATE TO HEAVY RAIN AND SMALL HAIL
AND OCCASIONAL STRONG WINDS GUSTS.
THE FLOODING AND SEVERE WEATHER POTENTIAL WILL RAMP UP EVEN FURTHER
TOMORROW AS THE UPPER TROUGH MOVES OUT OVER THE CENTRAL PLAINS AND A
SFC LOW DEEPENS. THE SFC LOW WILL SWING THROUGH THE SOUTH HIGH
PLAINS EARLY THIS EVENING BEFORE TURNING NEWD...RIPPLING ALONG A
QUASI-STATIONARY COLD FRONT AND WARM FRONT. BY THURSDAY
MORNING...THE LOW WILL ELONGATE FROM NWRN IL THROUGH NWRN MO...WITH
THE SFC WARM FRONT EXTENDING NEWD ACROSS CENTRAL LAKE MICHIGAN.
THIS WILL PUT THE CWA FIRMLY IN THE WARM SECTOR. WITH A WIDE OPEN
GLFMEX...DEEP LAYER MOISTURE WILL STREAM NWD INTO THE REGION...WITH
PWATS EXCEEDING 1.5 INCHES FOR AN EXTENDED PERIOD OF TIME...LEADING
TO THE POTENTIAL FOR SIGNIFICANT WIDESPREAD RIVER AND AREAL
FLOODING. SEE THE HYDROLOGY SECTION FOR FURTHER DETAILS.
THE SEVERE WEATHER MODE SHOULD FOCUS ON STRONG...DAMAGING WINDS AND
POSSIBLE TORNADOES. THE LATEST SPC DAY 2 CONVECTIVE OUTLOOK HAS
INCREASED THE AREA SOUTH OF A LINE FROM EVANSTON TO PONTIAC TO A
MODERATE RISK...WITH THE REMAINDER OF THE AREA IN A SLIGHT RISK.
INCREASING HEAT AND MOISTURE...TEMPERATURES REACHING INTO THE LOW TO
MIDDLE 70S AND DEW POINTS IN THE LOW TO MIDDLE 60S IN THE WARM
SECTOR...INSTABILITY WILL BE AMPLE. WHILE THE GENERAL CONVECTIVE
MODE WILL BE LINEAR WITH SMALL LINES AND BOWS POSSIBLE...PRODUCING
DAMAGING WINDS...THE MODEL GUIDANCE IS IN GOOD AGREEMENT ON A STRONG
LOW LEVEL JET...WITH SWLY WINDS OF 55-65KT ACROSS THE REGION. WHILE
SFC WINDS ARE GENERALLY PROGGED TO BE SOUTHERLY...THERE WILL BE
OPPORTUNITY FOR SFC WINDS TO BACK A LITTLE MORE EAST OF SOUTH AS THE
SFC LOW TRACKS THROUGH NWRN IL AND INTO SRN WI. GIVEN THE AMPLE
INSTABILITY...COMBINED WITH CLOCKWISE TURNING HODOGRAPHS...DISCRETE
SUPER CELLS MAY DEVELOP OUT IN THE WARM SECTOR AHEAD OF THE LINEAR
CONVECTION...WHICH WOULD BRING THE TORNADIC POTENTIAL TO THE
REGION.
THE POTENTIAL FOR SEVERE WEATHER AND HEAVY RAINFALL WILL CONTINUE
UNTIL THE ASSOCIATED COLD FRONT PUSHES THROUGH THE REGION...BRINGING
IN MUCH COOLER AIR. THE GUIDANCE IS IN GOOD AGREEMENT ON PUSHING
THE FRONT ACROSS THE AREA THURSDAY EVENING. AS THE SFC LOW PUSHES
OFF TO THE NORTHEAST...THE UPPER TROUGH WILL ALSO CROSS THE AREA.
WITH PLENTY OF RESIDUAL SFC MOISTURE AND COOLER AIR AND CYCLONIC
CURVATURE ALOFT...SOME LINGERING INSTABILITY SHOWERS SHOULD PERSIST
INTO FRIDAY. HIGHS ON FRIDAY SHOULD DROP BACK INTO THE MIDDLE TO
UPPER 40S.
KREIN
.LONG TERM - SATURDAY THROUGH WEDNESDAY...
SPRAWLING SURFACE HIGH PRESSURE TO BUILD INTO THE AREA SATURDAY
BEHIND DEPARTING SURFACE LOW/UPPER LEVEL TROUGH. A RETURN TO
UNSEASONABLY COOL TEMPS WITH A NEEDED BREAK IN PRECIPITATION WILL BE
SHORT LIVED HOWEVER AS THE UPPER FLOW QUICKLY RETURNS SOUTHWESTERLY
AS ANOTHER POWERFUL SHORTWAVE TROUGH DIGS INTO WESTERN NORTH AMERICA
ON SUNDAY. THIS SHORTWAVE CARVES OUT A TROUGH ACROSS THE MOUNTAIN
WEST SUNDAY NIGHT INTO MONDAY.
A SERIES OF UPPER LEVEL SHORT WAVE TROUGHS WILL THEN RIPPLE
NORTHEAST IN THE SW FLOW ALOFT. SPECIFIC FEATURES ARE POORLY
RESOLVED BY MEDIUM RANGE MODELS BUT OVERALL TREND WILL BE A RETURN
TO INCREASING MOISTURE AS GULF OPENS BACK UP AGAIN. MEDIUM RANGE
MODELS ARE IN FAIRLY GOOD AGREEMENT IN CONCEPT IN SAGGING THE
SURFACE FRONTAL BOUNDARY SOUTH ACROSS THE LOCAL AREA MONDAY NIGHT
AND STALLING IT OUT TUESDAY SETTING THE STAGE FOR ANOTHER PROLONGED
PERIOD OF WET WEATHER TUESDAY INTO WEDNESDAY AS RIPPLES OF LOW
PRESSURE LIFT NORTHEAST ALONG THE BOUNDARY.
EF
&&
.HYDROLOGY...
350 PM CDT
WITH SFC DEW POINTS EXPECTED TO REACH INTO THE LOWER TO MIDDLE 60S
AND PWATS POSSIBLY REACHING AS HIGH AS 1.75 INCHES...ANY
THUNDERSTORMS THAT DEVELOP WILL BE EFFICIENT RAIN PRODUCERS. BASED
ON THE MATT BUNKERS PWAT CLIMATOLOGY...THESE VALUES APPROACH
RECORD LEVELS. SO...FLOODING WILL BE A MAJOR CONCERN FOR THE
ENTIRE CWA...WITH STORM TOTAL PCPN AMOUNTS OF 2-3 INCHES OVER THE
SERN PORTIONS OF THE CWA...GENERALLY SOUTH OF I-80...AND 3-4
INCHES TO THE NORTH. LATEST LOCAL QPF WOULD SUGGEST AN AREA OF
PCPN OF 4-5 INCHES IS POSSIBLE ALONG OVER NORTHERN ILLINOIS. THIS
REPRESENTS AN INCREASE OVER PREVIOUS FORECASTS...BUT GIVEN THE
RECORD LEVEL PWATS FOR AN EXTENDED PERIOD OF TIME...CONFIDENCE IS
INCREASING FOR THIS SIGNIFICANT RAINFALL. WITH MANY RIVERS AND
STREAMS ARE ALREADY NEAR OR ABOVE MINOR FLOOD STAGE...THIS AMOUNT
OF RAIN WILL BRING ADDITIONAL RISES TO MODERATE AND MAJOR FLOOD
LEVEL. IN ADDITION TO RIVER FLOODING...AREAL FLOODING OR
RURAL...SUBURBAN AND URBAN AREAS IS LIKELY...WITH LOW LYING ROADS
AND VIADUCTS FLOODING...AS WELL AS...ROADSIDE DRAINAGE DITCHES AND
DRAINAGE PONDS EXCEEDING CAPACITY. AREAS NOT SEEING FLOODING WILL
AT LEAST SEE AREAS OF STANDING OR PONDING WATER ON ROADS.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* WIDESPREAD SHRA AND TS TONIGHT.
* PERIODS OF VERY HEAVY RAINFALL THROUGH THE PERIOD...WITH LOW VIS
UNDER 2 MILES AT TIMES.
* LOW LEVEL WIND SHEAR THIS EARLY THIS MORNING WITH A 50 KT
SOUTHERLY JET AT 2,000 FT AGL.
* WINDS SHIFTING OUT OF THE SOUTH AFTER 10 UTC WITH WINDS LIKELY
GUSTING TO 30 TO 35 KT AT TIMES THROUGH MUCH OF THE DAY.
* TIMING OF IMPROVING CONDITIONS BY THIS EVENING.
KJB
//DISCUSSION...UPDATED 06Z...
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO TRAIN NORTHEASTWARD FROM
MISSOURI ACROSS NORTHERN ILLINOIS OVERNIGHT TONIGHT. MOISTURE
TRANSPORT IS ABSOLUTELY IMPRESSIVE...WITH A 50 TO 60KT LOW LEVEL JET
CONTINUALLY PUMPING IN DEEPER MOISTURE. PRECIPITABLE WATER VALUES
ARE PROGGED TO INCREASE TO NEAR 1.6 INCHES WHICH IS NEAR RECORD
VALUES FOR THIS TIME OF YEAR. THE COMBINATION OF THIS DEEP MOISTURE
AND THE THE STRONG DYNAMIC FORCING FROM THIS SYSTEM WILL CONTINUE TO
SUPPORT CONVECTIVE ACTIVITY. THERE COULD BE A VERY SHORT BREAK IN
THE ACTIVITY AROUND DAYBREAK AT THE EASTERN TERMINALS AS THE WARM
FRONT SURGES NORTHWARD THROUGH THE NIGHT. HOWEVER...CONFIDENCE IN THIS
IS LOW.
ANY BREAK IN THE ACTIVITY...WOULD BE SHORT LIVED...AS ADDITIONAL
THUNDERSTORMS WILL MAKE A RETURN BY MID TO LATE MORNING. VERY HEAVY
RAINFALL WILL LIKELY ACCOMPANY THESE THUNDERSTORMS. IT ALSO APPEARS
THAT SEVERAL HOURS OF ADDITIONAL THUNDERSTORM ACTIVITY IS LIKELY
FROM MID TO LATE MORNING THROUGH MUCH OF THE AFTERNOON AS THE CLOUD
BEARING FLOW LOOKS TO REMAIN PARALLEL TO THE APPROACHING SURFACE
BOUNDARY...WHICH SHOULD RESULT IN TRAINING CELLS. THIS HEAVY RAIN
WILL LIKELY REDUCE VISIBILITY UNDER 2 SM AT TIMES...ESPECIALLY
DURING THE AFTERNOON.
WINDS WILL RAPIDLY INCREASE OUT OF THE SOUTH BY EARLY MORNING AS THE
WARM FRONT LIFTS NORTH OF THE AREA. DUE TO THE PRESENCE OF 50 KT OF
FLOW ONLY A COUPLE THOUSAND FEET OFF THE GROUND...SOME OF THIS
MOMENTUM WILL LIKELY BE MIXED TO THE SURFACE. THUS WINDS WILL LIKELY
GUST IN THE LOW TO MID 30 KT RANGE FOR MUCH OF THE DAY. EVEN HIGH
WINDS WILL BE POSSIBLE IN WITHIN THE STRONGER STORMS.
THUNDERSTORM ACTIVITY SHOULD BEGIN TO ABATE ACROSS THE AREA BY LATE
AFTERNOON OR EARLY IN THE EVENING. HOWEVER...THE WINDS WILL SHIFT
OUT OF THE WEST SOUTHWEST BEHIND A COLD FRONT BY MID EVENING. THE
WINDS WILL LIKELY REMAIN GUSTY UP AROUND 30 KT BEHIND THIS
FRONT...BUT THE THREAT FOR THUNDER SHOULD END.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
HIGH CONFIDENCE IN PERIODS OF HEAVY THUNDERSTORM RAIN.
LOW TO MEDIUM CONFIDENCE ON TIMING OF IMPROVING CONDITIONS LATER
TODAY.
MODERATE TO HIGH CONFIDENCE IN WINDS.
HIGH CONFIDENCE IN IFR AND LOWER VIS AND CIGS IN +TSRA ACTIVITY.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...VFR...CHANCE SHRA WITH LOCAL MVFR.
SATURDAY...VFR...LAKE BREEZE DEVELOPING AND REACHING CHI TERMINALS
EARLY-MID AFTERNOON.
SUNDAY...VFR...SLIGHT CHANCE SHRA.
MONDAY...VFR...CHANCE SHOWERS.
TUESDAY...MVFR LOWERING TO IFR....CHANCE OF SHOWERS.
TRS
&&
.MARINE...
420 PM CDT
A PAIR OF LOW PRESSURE CENTERS OVER NORTHERN MISSOURI AND THE
TEXAS PANHANDLE WILL MOVE NORTHEAST TONIGHT AND THURSDAY AND
OVERSPREAD THE GREAT LAKES AREA. A BRIEF PERIOD OF OCCASIONALLY
GALE FORCE GUSTS WILL OCCUR ACROSS SOUTHERN LAKE MICHIGAN
THURSDAY AS THE SURFACE PRESSURE GRADIENT INTENSIFIES SOUTH OF THE
ELONGATED LOW PRESSURE AREA FROM THE SAULT TO GREEN BAY.
AS LOW PRESSURE LOCATES NEAR MILWAUKEE THURSDAY EVENING AND THEN
MOVES NORTHEAST TO THE STRAITS OF MACKINAC BY DAYBREAK FRIDAY... A
POWERFUL COLD FRONT WILL SURGE EAST ACROSS THE LAKE WITH WINDS
INCREASING RAPIDLY BEHIND THE FRONT DURING THE PREDAWN HOURS
FRIDAY. WINDS WILL RAPIDLY REACH GALE FORCE TO 45 KTS FRIDAY WITH
A DIMINISHING TREND BEGINNING AFTER DARK FRIDAY EVENING. SURFACE
HIGH PRESSURE WILL BUILD INTO THE AREA SATURDAY BRINGING A PERIOD
OF LIGHT WINDS LASTING ONLY UNTIL DAYBREAK SUNDAY WHEN SOUTHERLY
FLOW WILL AGAIN INCREASE AHEAD OF AN APPROACHING FRONTAL BOUNDARY.
ED F
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 7 AM FRIDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 AM
FRIDAY.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 AM FRIDAY TO 4 AM
SATURDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742...7 AM THURSDAY TO 7 PM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 7 AM THURSDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...7 AM THURSDAY TO 10 PM
THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1059 PM CDT WED APR 17 2013
.DISCUSSION...
934 PM CDT
EVENING/MESOSCALE UPDATE...
HAVE CANCELLED REMAINING CONVECTIVE WATCHES...THOUGH FLOODING WILL
CONTINUE TO BE A SIGNIFICANT ISSUE THROUGH THURSDAY AND BEYOND.
WARM FRONT EXTENDS FROM LOW PRESSURE WAVE OVER WESTERN MISSOURI...
NORTHEAST INTO CENTRAL ILLINOIS AND CENTRAL INDIANA AT 02Z. OUTFLOW
FROM PERSISTENT ELEVATED THUNDERSTORMS ACROSS IA/NORTHERN IL/IN HAS
CONTINUED TO SUPPRESS SURFACE WARM FRONT SOUTH OF THE CWA...AND WILL
LIKELY CONTINUE TO DO SO OVERNIGHT BEFORE DEEPENING SURFACE LOW
LIFTS FROM MISSOURI INTO NORTHWEST IL IN ASSOCIATION WITH SHORT WAVE
LIFTING OUT OF BASE OF UPPER TROUGH OVER THE SOUTHERN PLAINS.
UNFORTUNATELY...THIS WILL RESULT IN CONTINUED FORCED ASCENT ATOP
CONVECTIVELY ENHANCED FRONTAL ZONE TONIGHT WITHIN A BROAD REGION OF
PERSISTENT STRONG WARM/MOIST ADVECTION AHEAD OF DEEP UPPER TROUGH
OVER THE PLAINS.
ILX 00Z SOUNDING TELLS THE STORY WITH RESPECT TO THE DIMINISHED
SEVERE THREAT WITH STRONG LOW LEVEL INVERSION NORTH OF FRONT
PREVENTING NEAR SFC-BASED STORMS. RAP GUIDANCE CONTINUES TO DEPICT A
GRADIENT IN THE MUCAPE FIELD INCREASING TO 500-1000 J/KG AS YOU MOVE
FARTHER SOUTH OF I-80. WHILE EFFECTIVE BULK SHEAR IN EXCESS OF 60 KT
WILL CONTINUE TO ALLOW SOME ORGANIZATION FOR ELEVATED CONVECTION
NORTH OF WARM FRONT...THE THREAT OF SEVERE WEATHER SHOULD BE
LIMITED TO MARGINAL HAIL WITH THE BETTER ORGANIZED STORMS.
WHILE THE SEVERE THREAT INTO THE OVERNIGHT HOURS IS RATHER LOW...
FLOODING THREAT CONTINUES TO BE SIGNIFICANT INTO THURSDAY. RADAR
ESTIMATES AND OBSERVED RAINFALL REPORTS INDICATE THAT MOST AREAS
HAVE SEEN UPWARDS OF 0.75 INCHES OF RAIN...WITH MANY AREAS BETWEEN
1.5 AND 2.0 INCHES AND PARTS OF NORTH CENTRAL ILLINOIS IN EXCESS OF
2.5 INCHES. ILX 00Z RAOB DEPICTS PWAT OF 1.38 INCHES...199 PERCENT
OF NORMAL...AN INDICATION OF THE VERY MOIST AIR MASS. ADDITIONAL
RAINFALL AMOUNTS IN THE 1-2 INCH RANGE ARE VERY LIKELY THROUGH
THURSDAY...LIKELY LEADING TO EXTENSIVE FLOODING ON AREA STREAMS AND
RIVERS. AERIAL FLOOD WARNINGS REMAIN IN EFFECT INTO MIDDAY
THURSDAY...AND MANY RIVER FORECAST SITES ARE HEADED FOR MODERATE TO
MAJOR FLOODING.
RATZER
//PREV DISCUSSION...
342 PM CDT
.SHORT TERM...THROUGH FRIDAY...
HAZARDOUS WEATHER ISSUES FROM SEVERE THUNDERSTORMS TO EXCESSIVE
RAINFALL TO TORNADIC POTENTIAL WILL IMPACT THE REGION THROUGH
THURSDAY NIGHT.
FOR THE REMAINDER OF THE AFTERNOON AND INTO THIS EVENING...AT 230PM
CDT...STRONG THUNDERSTORMS EXTEND ALONG A LINE FROM NEAR
WAUKEGAN...SOUTHWEST THROUGH OTTAWA. WEST OF THIS LINE...AN
EXTENSIVE AREA OF OVERRUNNING PCPN WITH EMBEDDED THUNDER EXTENDED
BACK THROUGH ERN IOWA AND MISSOURI. MUCH OF THE ACTIVITY OVER NRN
IL HAS FORMED ALONG AN ELEVATED WARM FRONT...BUT A MORE SOLID LINE
HAS DEVELOPED IN THE WARM SECTOR. EXPECT THAT THE THUNDERSTORMS
WILL SAG SEWD THROUGH THE EVENING...BRINGING SHOWERS AND
THUNDERSTORMS INTO EAST-CENTRAL ILLINOIS AND NORTHWESTERN INDIANA.
WITH COPIOUS AMOUNTS OF MOISTURE STREAMING INTO THE REGION...THE
STORMS HAVE BEEN VERY EFFICIENT RAIN PRODUCERS...WITH 0.81 INCHES OF
RAIN MEASURED AT THE ROCKFORD AIRPORT BTWN 12-18Z THIS MORNING.
STORMS HAVE ALSO BEEN MARGINALLY SEVERE WITH NUMEROUS REPORTS OF
SMALL HAIL RECEIVED...AND A FEW REPORTS OF LARGER HAIL AS WELL.
THIS WILL BE THE CONVECTIVE MODE FOR THE REMAINDER OF THE EVENING
AND OVERNIGHT TONIGHT...WITH MODERATE TO HEAVY RAIN AND SMALL HAIL
AND OCCASIONAL STRONG WINDS GUSTS.
THE FLOODING AND SEVERE WEATHER POTENTIAL WILL RAMP UP EVEN FURTHER
TOMORROW AS THE UPPER TROUGH MOVES OUT OVER THE CENTRAL PLAINS AND A
SFC LOW DEEPENS. THE SFC LOW WILL SWING THROUGH THE SOUTH HIGH
PLAINS EARLY THIS EVENING BEFORE TURNING NEWD...RIPPLING ALONG A
QUASI-STATIONARY COLD FRONT AND WARM FRONT. BY THURSDAY
MORNING...THE LOW WILL ELONGATE FROM NWRN IL THROUGH NWRN MO...WITH
THE SFC WARM FRONT EXTENDING NEWD ACROSS CENTRAL LAKE MICHIGAN.
THIS WILL PUT THE CWA FIRMLY IN THE WARM SECTOR. WITH A WIDE OPEN
GLFMEX...DEEP LAYER MOISTURE WILL STREAM NWD INTO THE REGION...WITH
PWATS EXCEEDING 1.5 INCHES FOR AN EXTENDED PERIOD OF TIME...LEADING
TO THE POTENTIAL FOR SIGNIFICANT WIDESPREAD RIVER AND AREAL
FLOODING. SEE THE HYDROLOGY SECTION FOR FURTHER DETAILS.
THE SEVERE WEATHER MODE SHOULD FOCUS ON STRONG...DAMAGING WINDS AND
POSSIBLE TORNADOES. THE LATEST SPC DAY 2 CONVECTIVE OUTLOOK HAS
INCREASED THE AREA SOUTH OF A LINE FROM EVANSTON TO PONTIAC TO A
MODERATE RISK...WITH THE REMAINDER OF THE AREA IN A SLIGHT RISK.
INCREASING HEAT AND MOISTURE...TEMPERATURES REACHING INTO THE LOW TO
MIDDLE 70S AND DEW POINTS IN THE LOW TO MIDDLE 60S IN THE WARM
SECTOR...INSTABILITY WILL BE AMPLE. WHILE THE GENERAL CONVECTIVE
MODE WILL BE LINEAR WITH SMALL LINES AND BOWS POSSIBLE...PRODUCING
DAMAGING WINDS...THE MODEL GUIDANCE IS IN GOOD AGREEMENT ON A STRONG
LOW LEVEL JET...WITH SWLY WINDS OF 55-65KT ACROSS THE REGION. WHILE
SFC WINDS ARE GENERALLY PROGGED TO BE SOUTHERLY...THERE WILL BE
OPPORTUNITY FOR SFC WINDS TO BACK A LITTLE MORE EAST OF SOUTH AS THE
SFC LOW TRACKS THROUGH NWRN IL AND INTO SRN WI. GIVEN THE AMPLE
INSTABILITY...COMBINED WITH CLOCKWISE TURNING HODOGRAPHS...DISCRETE
SUPER CELLS MAY DEVELOP OUT IN THE WARM SECTOR AHEAD OF THE LINEAR
CONVECTION...WHICH WOULD BRING THE TORNADIC POTENTIAL TO THE
REGION.
THE POTENTIAL FOR SEVERE WEATHER AND HEAVY RAINFALL WILL CONTINUE
UNTIL THE ASSOCIATED COLD FRONT PUSHES THROUGH THE REGION...BRINGING
IN MUCH COOLER AIR. THE GUIDANCE IS IN GOOD AGREEMENT ON PUSHING
THE FRONT ACROSS THE AREA THURSDAY EVENING. AS THE SFC LOW PUSHES
OFF TO THE NORTHEAST...THE UPPER TROUGH WILL ALSO CROSS THE AREA.
WITH PLENTY OF RESIDUAL SFC MOISTURE AND COOLER AIR AND CYCLONIC
CURVATURE ALOFT...SOME LINGERING INSTABILITY SHOWERS SHOULD PERSIST
INTO FRIDAY. HIGHS ON FRIDAY SHOULD DROP BACK INTO THE MIDDLE TO
UPPER 40S.
KREIN
.LONG TERM - SATURDAY THROUGH WEDNESDAY...
SPRAWLING SURFACE HIGH PRESSURE TO BUILD INTO THE AREA SATURDAY
BEHIND DEPARTING SURFACE LOW/UPPER LEVEL TROUGH. A RETURN TO
UNSEASONABLY COOL TEMPS WITH A NEEDED BREAK IN PRECIPITATION WILL BE
SHORT LIVED HOWEVER AS THE UPPER FLOW QUICKLY RETURNS SOUTHWESTERLY
AS ANOTHER POWERFUL SHORTWAVE TROUGH DIGS INTO WESTERN NORTH AMERICA
ON SUNDAY. THIS SHORTWAVE CARVES OUT A TROUGH ACROSS THE MOUNTAIN
WEST SUNDAY NIGHT INTO MONDAY.
A SERIES OF UPPER LEVEL SHORT WAVE TROUGHS WILL THEN RIPPLE
NORTHEAST IN THE SW FLOW ALOFT. SPECIFIC FEATURES ARE POORLY
RESOLVED BY MEDIUM RANGE MODELS BUT OVERALL TREND WILL BE A RETURN
TO INCREASING MOISTURE AS GULF OPENS BACK UP AGAIN. MEDIUM RANGE
MODELS ARE IN FAIRLY GOOD AGREEMENT IN CONCEPT IN SAGGING THE
SURFACE FRONTAL BOUNDARY SOUTH ACROSS THE LOCAL AREA MONDAY NIGHT
AND STALLING IT OUT TUESDAY SETTING THE STAGE FOR ANOTHER PROLONGED
PERIOD OF WET WEATHER TUESDAY INTO WEDNESDAY AS RIPPLES OF LOW
PRESSURE LIFT NORTHEAST ALONG THE BOUNDARY.
EF
&&
.HYDROLOGY...
350 PM CDT
WITH SFC DEW POINTS EXPECTED TO REACH INTO THE LOWER TO MIDDLE 60S
AND PWATS POSSIBLY REACHING AS HIGH AS 1.75 INCHES...ANY
THUNDERSTORMS THAT DEVELOP WILL BE EFFICIENT RAIN PRODUCERS. BASED
ON THE MATT BUNKERS PWAT CLIMATOLOGY...THESE VALUES APPROACH
RECORD LEVELS. SO...FLOODING WILL BE A MAJOR CONCERN FOR THE
ENTIRE CWA...WITH STORM TOTAL PCPN AMOUNTS OF 2-3 INCHES OVER THE
SERN PORTIONS OF THE CWA...GENERALLY SOUTH OF I-80...AND 3-4
INCHES TO THE NORTH. LATEST LOCAL QPF WOULD SUGGEST AN AREA OF
PCPN OF 4-5 INCHES IS POSSIBLE ALONG OVER NORTHERN ILLINOIS. THIS
REPRESENTS AN INCREASE OVER PREVIOUS FORECASTS...BUT GIVEN THE
RECORD LEVEL PWATS FOR AN EXTENDED PERIOD OF TIME...CONFIDENCE IS
INCREASING FOR THIS SIGNIFICANT RAINFALL. WITH MANY RIVERS AND
STREAMS ARE ALREADY NEAR OR ABOVE MINOR FLOOD STAGE...THIS AMOUNT
OF RAIN WILL BRING ADDITIONAL RISES TO MODERATE AND MAJOR FLOOD
LEVEL. IN ADDITION TO RIVER FLOODING...AREAL FLOODING OR
RURAL...SUBURBAN AND URBAN AREAS IS LIKELY...WITH LOW LYING ROADS
AND VIADUCTS FLOODING...AS WELL AS...ROADSIDE DRAINAGE DITCHES AND
DRAINAGE PONDS EXCEEDING CAPACITY. AREAS NOT SEEING FLOODING WILL
AT LEAST SEE AREAS OF STANDING OR PONDING WATER ON ROADS.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* WIDESPREAD -RA TO RA DURING THE NIGHT WITH PERIODS OF TS AND +RA.
* WIDESPREAD MVFR WITH AND AREAS IFR OVERNIGHT...IMPROVING
DAYBREAK OR SOON THEREAFTER.
* ENE SFC GRADUALLY BECOME SSE AND BECOMING MODERATELY GUSTY BY
DAYBREAK...AND INCREASINGLY GUSTY FROM SSE-SSW WINDS DURING THE
DAY.
TRS
//DISCUSSION...UPDATED 00Z...
MULTIPLE SHORT WAVES CONTINUE/TO CONTINUE TO MOVE FROM THE
SOUTHERN PLAINS NORTHEASTWARD ACROSS THE MID MO AND MID AND UPPER
MS VALLEYS TO THE WESTERN GREAT LAKES TONIGHT AND THU AS THE
UPPER UPPER TROUGH CONTINUE TO MOVE E FROM THE ROCKIES AND OVER
THE PLAINS.
THESE MULTIPLE SMALL TO MEDIUM DISTURBANCES ARE EXPECTED TO
CONTINUE TO PERIODICALLY CAUSE INCREASED RA COVERAGE AND NUMBER
OF TS OVER THE CHI TERMINALS ALONG AND N OF THE SURFACE BOUNDARY
TONIGHT AS THEY LIFT NE TOWARD AN THEN OVER THE LOCAL AREA.
PROFILER...VAD AND RAOB WIND MEASUREMENTS CONFIRM INCREASING S TO
SW FLOW ABOVE THE INCREASINGLY SHALLOW BOUNDARY LAYER WITH SPEED
OF 50 TO 60KT WITHIN 1 TO 2K FT OF SURFACE BY LATE OVERNIGHT
TONIGHT AND HAVE CONTINUED LLWS FORECASTS DURING THE NIGHT IN 00Z
SET OF TAFORS.
MVFR AND AREAS OF IFR CEILINGS EXPECTED TO PERSIST N OF THE
SURFACE FRONT TIL IT LIFTS NORTHWARD AND ACROSS THE LOCAL
TERMINALS DURING THE PREDAWN TO EARLY MORNING HOURS OF THU. WITH
THE WARM FRONT TO THE N OF THE LOCAL AREA BY EARLY THU MORNING THE
STRONGEST FORCING RESULTING FROM THE VERY STRONG LOW LEVEL WAA AND
CONVERGENCE IS ANTICIPATED TO SHIFT GENERALLY TO THE N OF THE
LOCAL TERMINALS THOUGH ACROSS THE LOCAL AREA S OF THE BOUNDARY
SURFACE BASED INSTABILITY WILL BE INCREASING DURING THU SO CANNOT
RULE OUT SCATTERED TSRA FROM MID AFTERNOON INTO EARLY EVENING.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH CONFIDENCE IN FORECAST WIND TRENDS.
* MODERATE CONFIDENCE IN TIMING OF TIME FRAMES FOR MORE
WIDESPREAD RA AND +TSRA.
* LOW CONFIDENCE IN ONSET OF WIDESPREAD IFR AND IMPROVEMENT BACK
THROUGH MVFR TO IFR THU MORNING.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...VFR...CHANCE SHRA WITH LOCAL MVFR.
SATURDAY...VFR...LAKE BREEZE DEVELOPING AND REACHING CHI TERMINALS
EARLY-MID AFTERNOON.
SUNDAY...VFR...SLIGHT CHANCE SHRA.
MONDAY...VFR...CHANCE SHOWERS.
TUESDAY...MVFR LOWERING TO IFR....CHANCE OF SHOWERS.
TRS
&&
.MARINE...
420 PM CDT
A PAIR OF LOW PRESSURE CENTERS OVER NORTHERN MISSOURI AND THE
TEXAS PANHANDLE WILL MOVE NORTHEAST TONIGHT AND THURSDAY AND
OVERSPREAD THE GREAT LAKES AREA. A BRIEF PERIOD OF OCCASIONALLY
GALE FORCE GUSTS WILL OCCUR ACROSS SOUTHERN LAKE MICHIGAN
THURSDAY AS THE SURFACE PRESSURE GRADIENT INTENSIFIES SOUTH OF THE
ELONGATED LOW PRESSURE AREA FROM THE SAULT TO GREEN BAY.
AS LOW PRESSURE LOCATES NEAR MILWAUKEE THURSDAY EVENING AND THEN
MOVES NORTHEAST TO THE STRAITS OF MACKINAC BY DAYBREAK FRIDAY... A
POWERFUL COLD FRONT WILL SURGE EAST ACROSS THE LAKE WITH WINDS
INCREASING RAPIDLY BEHIND THE FRONT DURING THE PREDAWN HOURS
FRIDAY. WINDS WILL RAPIDLY REACH GALE FORCE TO 45 KTS FRIDAY WITH
A DIMINISHING TREND BEGINNING AFTER DARK FRIDAY EVENING. SURFACE
HIGH PRESSURE WILL BUILD INTO THE AREA SATURDAY BRINGING A PERIOD
OF LIGHT WINDS LASTING ONLY UNTIL DAYBREAK SUNDAY WHEN SOUTHERLY
FLOW WILL AGAIN INCREASE AHEAD OF AN APPROACHING FRONTAL BOUNDARY.
ED F
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 7 AM FRIDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 AM
FRIDAY.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 AM FRIDAY TO 4 AM
SATURDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742...7 AM THURSDAY TO 7 PM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 7 AM THURSDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...7 AM THURSDAY TO 10 PM
THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1234 AM CDT THU APR 18 2013
...UPDATED AVIATION SECTION...
.SYNOPSIS...
ISSUED AT 1140 PM CDT WED APR 17 2013
A STRONG MID TO UPPER LEVEL TROUGH OF LOW PRESSURE IS CURRENTLY
POSITIONED ACROSS THE CENTRAL AND NORTHERN ROCKIES WITH A MID TO
UPPER LEVEL RIDGE OF HIGH PRESSURE ACROSS THE SOUTHEAST UNITED
STATES. THIS PLACES WESTERN KANSAS UNDER SOUTHWEST FLOW ALOFT.
TOWARDS THE SURFACE, AN AREA OF LOW PRESSURE IS CURRENTLY LOCATED
ACROSS THE KS/MO BORDER WITH AN ASSOCIATED COLD FRONT STRETCHING
SOUTHWEST ACROSS OKLAHOMA. NORTHERLY WINDS ARE OBSERVED ACROSS THE
FORECAST AREA WITH MOSTLY CLOUDY SKIES. SHOWERS AND THUNDERSTORMS
CONTINUE ACROSS CENTRAL AND SOUTH CENTRAL KANSAS WITH LIGHTER
PRECIPITATION FALLING WEST OF THIS AREA. TEMPERATURES HAVE FALLEN
BELOW FREEZING ACROSS PORTIONS OF WEST CENTRAL AND SOUTHWEST
KANSAS ALLOWING A WINTRY MIX TO BE OBSERVED. RAIN, DRIZZLE,
FREEZING DRIZZLE, SLEET, SNOW, AND SMALL HAIL HAVE BEEN REPORTED
IN AREAS WEST OF HAYS TO MEADE LATE THIS EVENING. NO REPORTS OF
ACCUMULATION HAVE BEEN REPORTED AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 343 PM CDT WED APR 17 2013
THERE WILL BE A CONTINUED THREAT FOR SEVERE WEATHER OVER SOUTH
CENTRAL KANSAS THIS EVENING. THE NAM IS INDICATING THAT THE 850 MB
FRONTAL BOUNDARY WILL BE IN THE AREA FROM COLDWATER AND MEDICINE
LODGE TO ST JOHN THIS EVENING BEFORE SHIFTING SOUTH OF THE AREA BY
MIDNIGHT. RAP MODEL SOUNDINGS SHOW AROUND 1500 J/KG OF ELEVATED CAPE
IN THAT AREA. AS THE SOUTHWESTERN U.S. UPPER JET PROPAGATES EASTWARD
INTO THE SOUTHERN PLAINS THIS EVENING...INCREASING UPWARD VERTICAL
MOTION COULD AID IN THE DEVELOPMENT OF ADDITIONAL THUNDERSTORMS.
THERE WILL BE A THREAT FOR HAIL UP TO QUARTER SIZE IN THAT AREA.
THE UPPER TROUGH MOVES EAST OUT OVER THE HIGH PLAINS TONIGHT. MODEL
SOUNDINGS ARE INDICATING SATURATED CONDITIONS GENERALLY BELOW 700 MB
THROUGH THE NIGHT WITH THE LEVELS ABOVE 700 MB SATURATING FOR A 3-6
HOUR TIME FRAME DURING THE NIGHT. LOCATIONS FARTHER WEST ACROSS
WESTERN KANSAS WILL SEE AREAS OF DRIZZLE CONTINUING ALONG WITH A
CHANCE FOR RAIN SHOWERS. THERE WILL BE A TRANSITION FROM RAIN TO
SNOW WITH A PERIOD OF SLEET/FREEZING RAIN POSSIBLE IN BETWEEN. THE
ATMOSPHERE SHOULD COOL OFF ENOUGH FOR SNOW TO DEVELOP OVER WEST
CENTRAL KANSAS DURING THE EVENING HOURS WITH THIS SPREADING INTO
CENTRAL KANSAS AFTER MIDNIGHT. GIVEN THE SHORT WINDOW OF OPPORTUNITY
FOR THE SEEDER/FEEDER MECHANISM TO OCCUR...DO NOT EXPECT SNOW
AMOUNTS TO BE SIGNIFICANT WITH ONLY SOME LIGHT ACCUMULATIONS
POSSIBLE ON GRASSY AREAS. AM NOT ANTICIPATING ANY SIGNIFICANT ICE
ACCUMULATIONS TO OCCUR ALTHOUGH SOME ELEVATED SURFACES COULD GET
SOME LIGHT COATINGS.
AS COLD AIR ADVECTION INCREASES...STRONG NORTHERLY WINDS DEVELOP
OVER THE WESTERN HIGH PLAINS AND SPREAD EASTWARD TONIGHT. LOW LEVEL
WINDS THROUGH THE 850 MB LEVEL INCREASE TO 40-50 KNOTS OVERNIGHT
WHICH SHOULD SUPPORT WIND ADVISORY CRITERIA WINDS LATER TONIGHT INTO
THURSDAY MORNING. HAVE ISSUED A WIND ADVISORY FOR MIDNIGHT TONIGHT
UNTIL NOON THURSDAY FOR ALL OF SOUTHWEST AND CENTRAL KANSAS.
PRECIPITATION SHOULD BE WINDING DOWN FAIRLY QUICKLY LATE TONIGHT AND
THURSDAY MORNING AS THE UPPER SYSTEM MOVES EAST OF THE REGION.
CLOUDS SHOULD BE BREAKING UP FROM WEST TO EAST DURING THE DAY. WITH
SOME SUN...AFTERNOON HIGH TEMPERATURES MAY BE ABLE TO CLIMB INTO THE
LOWER 40S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 338 PM CDT WED APR 17 2013
FRIDAY:
UPPER LEVEL WNW FLOW WILL CONTINUE ON FRIDAY. AT THE SURFACE, HIGH
PRESSURE WILL RIDGE ACROSS THE PLAINS. NORTHWESTERLY WINDS WILL
EVENTUALLY BECOME SOUTHERLY AFTER SUNSET. HIGHS WILL BE IN THE 50S
AND LOWS WILL BE IN THE 20S. NO PRECIPITATION IS EXPECTED AS DRY
FLOW ALOFT AND LACK OF BL MOISTURE CONTINUES.
WEEKEND:
AN UPPER LEVEL TROUGH WILL DIG ACROSS THE CENTRAL AND SOUTHERN
ROCKIES THROUGH THE WEEKEND. THIS WILL PROMOTE A WARM AIR ADVECTION
PATTERN DOWNSTREAM ACROSS OUR REGION. A WARM 850 HPA PLUME WILL
ADVECT OFF THE ROCKIES AND OUT ACROSS SOUTHWEST KANSAS SATURDAY.
THIS WILL FAVOR DEEP MIXING AND HIGHS IN THE UPPER 60S TO LOWER 70S.
OVERNIGHT LOWS WILL MODERATE AS WELL WITH 30S ON SATURDAY AND 40S ON
SUNDAY. TEMPERATURES AROUND 70 DEG F CAN BE EXPECTED SUNDAY AS THE
AFOREMENTIONED WARM PLUME CONTINUES ACROSS THE REGION. THERE COULD BE
A FEW SHOWERS ACROSS SC/S KANSAS IN ASSOCIATION WITH WARM ADVECTION
BUT CONFIDENCE IS LOW AND MODELS ARE FAIRLY LIGHT ON QPF.
NEXT WEEK AND BEYOND:
A MAJOR CHANGE IN WEATHER IS POSSIBLE MONDAY OR TUESDAY. ANOTHER TROF
DIGGING OUT OF THE NORTHERN ROCKIES WILL USHER IN THE PASSAGE OF A
SIGNIFICANT COLD FRONT. THE ECMWF IS FAIRLY COLD WITH 850 HPA
TEMPERATURES DECREASING DOWN TO -6 DEG C. BOTH THE GFS AND ECMWF
INDICATE SOME LIGHT SNOWFALL ACROSS THE REGION ASSOCIATED WITH THIS
FRONT. CONFIDENCE IS LOW FOR PRECIPITATION TYPE BUT THERE IS HIGHER
CONFIDENCE IN LOWER TEMPERATURES WITH 40S AND 50S FOR HIGHS BY
TUESDAY/WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1228 AM CDT THU APR 18 2013
MVFR TO IFR CONDITIONS WILL CONTINUE ACROSS THE TAF SITES
EARLY THIS MORNING AS A STRONG STORM SYSTEM MOVES THROUGH THE
CENTRAL PLAINS. TEMPERATURES HAVE FALLEN TO BELOW FREEZING AT THE
SURFACE BUT A WARM TOUNGE ALOFT SHOULD KEEP MOST PRECIPITATION FROM
TURNING TO SNOW. I HAVE PLACED FREEZING RAIN IN THE TAFS FOR NOW
WITH THE ONLY MENTION OF SNOW IN THE GCK TAF AS PART OF A TEMPO
GROUP. HOWEVER, TEMPERATURES MAY FALL MORE RAPIDLY THAN EXPECTED
ALLOWING SNOW TO BE POSSIBLE CLOSER TO DAY BREAK. CLOUDY SKIES
CONTINUE THROUGHOUT THE DAY WITH SOME CLEARING LATE THIS EVENING.
STRONG NORTHERLY WINDS WILL BE FELT WITH THIS SYSTEM AND
CONTINUE THROUGHOUT THE DAY. A DECREASE IN WINDS AND A SHIFT TO
THE NORTHWEST IS EXPECTED TOMORROW EVENING INTO TOMORROW NIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 24 59 34 69 / 0 0 0 10
GCK 22 60 33 68 / 0 0 0 10
EHA 23 60 33 70 / 0 0 0 10
LBL 23 60 33 71 / 0 0 0 10
HYS 23 58 33 64 / 0 0 0 10
P28 28 60 36 66 / 0 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL NOON CDT /11 AM MDT/ TODAY FOR KSZ030-031-
043>046-061>066-074>081-084>090.
&&
$$
SYNOPSIS...HOVORKA_42
SHORT TERM...GERARD
LONG TERM...SUGDEN
AVIATION...HOVORKA_42
AREA FORECAST DISCUSSION
NWS WICHITA KS
1226 AM CDT THU APR 18 2013
.UPDATE...
ISSUED AT 1226 AM CDT THU APR 18 2013
UPDATED TO AVIATION SECTION BELOW.
&&
UPDATE ISSUED AT 711 PM CDT WED APR 17 2013
THUNDERSTORMS HAVE YET TO FORM ALONG THE SURFACE FRONT OVER
SOUTHEAST KS. INSPECTION OF MODIFIED RUC SOUNDINGS INDICATE POOR
LAPSE RATES/RELATIVELY WARM TEMPERATURES THROUGH
700-600MB. SO DESPITE GOOD CONVERGENCE ALONG THE SURFACE
FRONT...NEAR-SURFACE COLD AIR IS LIKELY TOO SHALLOW TO BREAK
THROUGH THE WARMER MID-LEVEL TEMPERATURES...WITH ONLY WEAK
BUOYANCY FROM THE SURFACE-700/600MB. CONSEQUENTLY...FEEL THE HIGH-
END SEVERE WEATHER THREAT INCLUDING TORNADOES...DAMAGING WINDS AND
VERY LARGE HAIL IS WANING...ALTHOUGH STILL CANNOT RULE OUT SEVERE
ACTIVITY EITHER DEVELOPMENT OVER MOVING NORTHEAST OUT OF OK INTO
SE KS.
WONDERING IF THE HIGHER CONFIDENCE SCENARIO (SUPPORTED BY THE
RUC)...IS SHOWERS/THUNDERSTORMS RAMPING UP IN COVERAGE/INTENSITY
LATER THIS EVENING OVER SOUTH-CENTRAL/CENTRAL KS IN RESPONSE TO
INCREASING ISENTROPIC ASCENT AND MOISTURE TRANSPORT AHEAD OF
APPROACHING DEEP MID/UPPER TROUGH...WITH A BROAD SHIELD OF
MODERATE TO HEAVY SHOWERS/THUNDERSTORMS PUSHING EAST ACROSS
EASTERN HALF OF KS OVERNIGHT ALONG THE ADVANCING 850-700MB FRONT.
GIVEN THE PRESENCE OF AMPLE ELEVATED INSTABILITY AND EFFECTIVE
DEEP LAYER SHEAR...LARGE HAIL IS POSSIBLE. POCKETS OF HEAVY RAIN
AND MINOR FLOODING ARE POSSIBLE...ALONG WITH MODEST RISES IN AREA
RIVERS...SO WILL KEEP THE FLOOD WATCH GOING OVER SOUTHEAST KS.
ADDITIONALLY...ENOUGH LOW-LEVEL COLD AIR MAY FILTER SOUTHEAST TO
RESULT IN A WINTRY MIX OVER CENTRAL KS AFTER MIDNIGHT...SO WILL
KEEP A WINTER WX ADVISORY GOING THERE.
ADK
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 237 PM CDT WED APR 17 2013
CONVECTION
PRE AND POST FRONTAL STRONG TO SEVERE CONVECTION WITH HEAVY
RAINFALL EXPECTED THRU THIS EVENING ACROSS PORTIONS OF CENTRAL
AND SOUTHEAST KANSAS. THE HIGHER IMPACT SEVERE IS STILL EXPECTED
ALONG THE SURFACE FRONT ACROSS SOUTHEAST KANSAS WITH DAMAGING
WINDS...LARGE HAIL AND A TORNADO POSSIBLE DURING THE EARLY
EVENING. HOWEVER ELEVATED INSTABILITY OVER THE COLD AIR WILL
STILL SUPPORT SOME HAILERS FURTHER WEST ACROSS PORTIONS OF
CENTRAL KANSAS. CONVECTION WILL TEND TO REDEVELOP AND
REPEAT/TRAIN OVER SOME AREAS WHICH PORTENDS TO HEAVY RAINFALL
AND FLOOD POTENTIAL. THE LONGER DURATION APPEARS TO BE OVER
SOUTHEAST KANSAS INTO THE OVERNIGHT HOURS...SO WILL ISSUE A
FLOOD WATCH FOR THESE AREAS.
WINTRY PRECIP
NEXT CHALLENGE IS WITH THE SURGE OF COLD AIR AND POST FRONTAL
PRECIPITATION LATER TONIGHT INTO THURSDAY MORNING. WHILE NOT
QUITE AS IMPRESSIVE AS LAST WEEK...IT DOES LOOK LIKE WE WILL GET
A TRANSIENT AREA OF A LIGHT WINTRY MIX ACROSS CENTRAL KANSAS WITH
THE NAM PREFERRED IN THIS REGARD. DEPENDING ON CHANGEOVER AND
MOISTURE DEPTH/LIFT...THIS COULD BE SOME LIGHT FREEZING RAIN
AND/OR SNOW OR FREEZING DRIZZLE...THOUGH FOR NOW ANY ACCUMS ARE
STILL EXPECTED TO BE LIGHT. THAT SAID...THIS IN COMBO WITH STRONG
NORTH WINDS NEAR ADVISORY CRITERIA INTO EARLY THURSDAY
MORNING...PLAN TO ISSUE A WINTER WEATHER ADVISORY FOR A PORTION
OF CENTRAL KANSAS. SOME LIGHT MIXED PRECIP COULD BE OBSERVED AS
FAR EAST AS THE FLINT HILLS INTO LATER THURSDAY MORNING...HOWEVER
TEMPERATURES SHOULD RECOVER TO A BIT ABOVE FREEZING BY THEN SO OF
LITTLE CONSEQUENCE EXPECTED.
FREEZE/RECORD COLD THURSDAY NIGHT
THE THIRD CONCERN IS WITH RECORD COLD AND WIDESPREAD FREEZE
EXPECTED. THIS LOOKS TO BE A PURE COLD ADVECTION TYPE WITH
MINS INTO THE MID TO UPPER 20S IN MOST LOCALES DESPITE A BIT
OF NOCTURNAL/EARLY MORNING WIND. CONSIDERED A HEADLINE/WATCH
FOR THIS...HOWEVER WITH THE OTHER MORE IMMINENT IMPACTS IN
THE SHORTER TERM HAVE DECIDED TO HOLD OFF AND MAINTAIN MENTION
IN THE HAZARDOUS WEATHER OUTLOOK. HOWEVER IF CONFIDENCE
REMAINS HIGH...A FREEZE WARNING WILL LIKELY BE FORTHCOMING IN
THE NEXT FORECAST CYCLE OR TWO.
SOME MODERATION AND RETURN TO DRY WEATHER IS EXPECTED FOR
FRIDAY AND SATURDAY AND MADE ONLY A SLIGHT UPTWEAK TO THE
TEMPERATURES CLOSER TO SEASONAL CLIMO BY SATURDAY.
DARMOFAL
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 237 PM CDT WED APR 17 2013
SINCE MAIN FOCUS HAS BEEN ON SHORT TERM DO NOT PLAN ON ANY
SIGNIFICANT CHANGES TO THE OUTER PERIODS WITH THIS FORECAST.
MEDIUM RANGE STILL SUPPORTS ANOTHER COOL DOWN EARLY NEXT
WEEK WITH SOME PRECIP CHANCES AHEAD OF AND JUST BEHIND THE
FRONTAL PASSAGE FROM SUNDAY INTO TUESDAY.
DARMOFAL
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1226 AM CDT THU APR 18 2013
AREAS OF SHOWERS/THUNDERSTORMS WILL GRADUALLY EXIT THE REGION TO
THE EAST AS THE OVERNIGHT PROGRESSES...AS A STRONG UPPER LEVEL
TROUGH APPROACHES FROM THE WEST. THINKING ACTIVITY THE REMAINDER
OF THE NIGHT WILL BE MOST WIDESPREAD AT KCNU. FURTHER NORTHWEST AT
KRSL...WILL LIKELY SEE A PERIODIC WINTRY MIX OF LIGHT SLEET...SNOW
AND PERHAPS PATCHY FREEZING DRIZZLE. SLEET/SNOW ACCUMULATIONS WILL
LIKELY ONLY BE A FEW TENTHS OF AN INCH AT BEST...AND ICE
ACCUMULATIONS ON ELEVATED SURFACES SHOULD BE LITTLE IF ANY.
OTHERWISE...IFR TO LOW MVFR CIGS WILL GRADUALLY GIVE WAY TO VFR
CIGS BY MID TO LATE MORNING THURSDAY ALL AREAS.
ADDITIONALLY...STRONG AND GUSTY NORTHWEST WINDS WILL PREVAIL
THROUGH THURSDAY.
ADK
&&
.FIRE WEATHER...
ISSUED AT 237 PM CDT WED APR 17 2013
GRASSLAND FIRE DANGER WILL REMAIN LOW DUE TO WIDESPREAD
PRECIPITATION TONIGHT INTO EARLY THURSDAY. A DRYING PROCESS
WILL BEGIN INTO THE START OF THE WEEKEND BEFORE ANOTHER CHANCE
FOR RAIN SUNDAY INTO EARLY NEXT WEEK.
KED
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 28 56 36 66 / 0 0 0 10
HUTCHINSON 27 56 35 64 / 0 0 0 10
NEWTON 27 54 35 64 / 0 0 0 10
ELDORADO 28 55 35 65 / 0 0 0 10
WINFIELD-KWLD 29 59 37 67 / 0 0 0 10
RUSSELL 24 56 34 64 / 0 0 0 10
GREAT BEND 25 56 34 64 / 0 0 0 10
SALINA 26 55 35 65 / 0 0 0 10
MCPHERSON 26 56 35 64 / 0 0 0 10
COFFEYVILLE 31 58 36 66 / 10 0 0 10
CHANUTE 30 57 33 65 / 10 0 0 10
IOLA 30 56 33 65 / 10 0 0 10
PARSONS-KPPF 30 56 34 65 / 10 0 0 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT THIS MORNING FOR KSZ032-
033-047-048-050-067-082.
FLOOD WATCH UNTIL 7 AM CDT THIS MORNING FOR KSZ070>072-094>096-
098>100.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1055 PM MDT WED APR 17 2013
.SHORT TERM...(THIS AFTERNOON THROUGH THURSDAY)
ISSUED AT 132 PM MDT WED APR 17 2013
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS POSITIVELY
TITLED LONGWAVE TROUGH EXTENDING SOUTH ALONG CENTRAL ROCKIES WITH
DRY SLOT/AREA OF SUBSIDENCE IN PLACE AHEAD OF THIS OVER WESTERN
KANSAS AND CENTRAL NEBRASKA. LOW AT THE SURFACE A STALLED FRONT
EXTENDS FROM THE TEXAS PANHANDLE ACROSS CENTRAL OKLAHOMA TO
SOUTHEAST KANSAS. NORTHWEST FLOW IS IN PLACE ACROSS OUR CWA WITH
VERY MOIST BL CONDITIONS PERSISTING...WHICH HAS RESULTED IN AREAS
OF FOG AND DRIZZLE PERSISTING THROUGH THE AFTERNOON HOURS. WITH
TEMPERATURES NEAR OR BELOW FREEZING...WE COULD CONTINUE TO SEE
LIGHT ICE ACCUMULATIONS ON ELEVATED SURFACES BEFORE SNOW DEVELOPS
LATER.
THE PRIMARY FORECAST FOCUS IS ON DEVELOPING WINTER STORM FOR
LATE THIS AFTERNOON THROUGH EARLY THURSDAY MORNING.
UPPER LEVEL TROUGH IS PROGGED TO SHIFT EAST THIS EVENING...WITH
LARGE SCALE ASCENT AND MID LEVEL MOISTURE OVERSPREADING THE CWA.
BROAD AXIS OF MID LEVEL FRONTOGENESIS IS EXPECTED TO SET UP ACROSS
THE NORTHWEST HALF OF OUR CWA THIS EVENING. LIGHT SNOW AND
BANDS OF MODERATE SNOW TRAINING FROM THE SOUTH TO THE NORTH. WITH
SURFACE TEMPS ALREADY BELOW FREEZING THIS AFTERNOON IN THE
NORTHWEST AND A SECOND COLD SURGE EXPECTED LATE THIS
AFTERNOON/EARLY THIS EVENING...I THINK WE SHOULD SEE A FAST
RAIN/SNOW CHANGEOVER WITH ALL SNOW IN OUR CWA THIS EVENING AND
TONIGHT. THERE IS QUITE A BIT OF SPREAD REGARDING QPF
VALUES...WITH GFS THE HIGH OUTLIER. WITH SREF (TRADITIONALLY HIGH)
AND OTHER GUIDANCE MORE IN LINE WITH PREVIOUS FORECAST QPF/SNOW
TOTALS I DISCOUNTED THE GFS SOLUTION AND ONLY MADE MINOR CHANGES
TO AMOUNTS. WE ARE CURRENTLY FORECAST 3-5 INCHES FOR MOST OF THE
AREA...WITH HIGHS AMOUNTS MORE LIKELY NORTH OF INTERSTATE 70.
OTHER CONCERN (AND POSSIBLY THE HIGHER IMPACT) IS STRONG WINDS
PROGGED TO DEVELOP THIS EVENING. ALL GUIDANCE IS SUPPORTIVE OF
GUSTY WINDS...HOWEVER GFS/MAV CONTINUES TO BE THE HIGH OUTLIER
WITH GUSTS IN EXCESS OF 60 MPH. NAM/SREF/ECMWF ALL ARE LOWER...AND
WITH BEST PRESSURE RISES ADVERTISED TO BE FURTHER SOUTH...THESE
SOLUTIONS MAY BE MORE REASONABLE. I USED A BLEND THAT FAVORED THE
NAM MIXED LAYER WINDS AND NUDGED A LITTLE TOWARDS GFS/MAV WHICH
RESULTS IN GUSTS THIS EVENING TO 50 MPH. EVEN WITH THE LOWER END
OF GUIDANCE WE SHOULD SEE BLOWING SNOW WITH REDUCED VISIBILITIES. THE
SPREAD IN GUIDANCE AND POSSIBLE LIMITED DURATION OF THE STRONGEST
WINDS IN OUR AREA RAISES QUESTIONS TO HOW LOW THESE VISIBILITIES WILL
BE AND HOW LONG. I FELT THE WINTER WEATHER ADVISORY WAS APPROPRIATE
WITH BRIEF BLIZZARD CONDITIONS POSSIBLE. IF WINDS END UP BEING MORE
IN LINE WITH GFS SOLUTION WE MAY NEED TO CONVERT WESTERN LOCATIONS TO
A BLIZZARD WARNING...CONFIDENCE JUST ISNT THERE RIGHT NOW.
THE WORST CONDITIONS SHOULD BE 03Z THROUGH ABOUT 09Z TONIGHT...WITH
SNOW ENDING QUICKLY FROM THE WEST TO THE EAST EARLY THU MORNING.
WE COULD SEE LINGERING SNOW INTO THU IN OUR NORTHEAST...HOWEVER
WITH BEST FORCING/MOISTURE OUTSIDE OUR AREA I AM NOT ANTICIPATING
VERY MUCH ADDITIONAL ACCUMULATION. WE SHOULD SEE ANOTHER BLUSTERY
DAY THURSDAY WITH HIGHS IN THE 30S AND GUSTY WINDS THROUGH THE
DAY. GFS/MAV IS AGAIN MUCH HIGHER ON WINDS THU AND MIGHT SUPPORT
ADVISORY CRITERIA. I WILL HAVE TO SEE WHAT KIND OF BIAS THE GFS
HAD TONIGHT TO HAVE ANY ANY CONFIDENCE IN THE HIGHER WINDS THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 316 PM MDT WED APR 17 2013
FORECAST PROBLEMS WILL BE HOW MUCH IT WARMS UP THROUGH THE WEEKEND
BEFORE THE NEXT COLD FRONT MOVES THROUGH AND THE PRECIPITATION
CHANCES THIS WEEKEND AND CONTINUING INTO THE BEGINNING OF NEXT WEEK.
SATELLITE SHOWING THE LARGE SCALE FLOW PATTERN BEING AMPLIFIED AND
BLOCKY FROM THE PACIFIC INTO THE EASTERN NORTH AMERICA.
THURSDAY NIGHT...SYSTEM THAT WILL HAVE BROUGHT THE AREA SNOW AND
WIND WILL CONTINUE TO MOVE AWAY. MODERATE GRADIENT CONTINUES THROUGH
THE NIGHT AND LOOKS LIKE THE WINDS WILL STAY UP ENOUGH TO KEEP THE
TEMPERATURES FROM BOTTOMING OUT.
FRIDAY/FRIDAY NIGHT...RIGHT REAR QUADRANT OF UPPER JET GOES ACROSS
THE NORTHERN PORTION OF THE AREA DURING THE DAY. AT THIS TIME WITH
A LARGE DRY LAYER IN THE LOW AND MID LEVELS...THIS ONLY LOOKS LIKE
IT WILL SPREAD CLOUDS ACROSS THE AREA. DURING THE NIGHT...THE LEFT
FRONT QUADRANT IS NEAR OR JUST SOUTHWEST OF THE SOUTHWEST PORTION OF
OUR AREA. AS IT LOOKS THE MAIN MID LEVEL LIFT LOOKS TO STAY TO NORTH
AND SOUTH OF THE AREA. ALSO PROBLEM AGAIN LOOKS TO BE A LACK OF
MOISTURE IN THE LOW LEVELS. SO WILL KEEP THIS PERIOD DRY AS WELL.
CLOUDS WILL DECREASE THROUGH THE NIGHT WITH THE MODELS SHOWING A
HIGHLY VARIABLE WIND FIELD AND DISAGREE WITH EACH OTHER. WILL TEND
TOWARD THE COOLER SIDE.
SATURDAY...MAIN JET REMAINS SOUTH AND WEST OF THE AREA. HIGHER LEVEL
CLOUD COVER INCREASES THROUGH THE DAY AS A COUPLE DIFFERENT SHORTWAVE
TROUGHS MOVE THROUGH. THIS MAY HINDER THE TEMPERATURES. HOWEVER...
MODELS HAVE BEEN MISSING THE BOAT ON TEMPERATURES HERE RECENTLY. HAVE
A LIGHT AND VARIABLE WIND FIELD WHICH ALSO DOES NOT BODE WELL FOR
GOING TOO WARM. MODELS HANDLE THIS DIFFERENTLY DUE TO THE DIFFERENT
HANDLING OF THE INCOMING SYSTEM. 700 TO 500 MB PATTERN WOULD
DEFINITELY SUPPORT AN EARLIER SURFACE TROUGH/FRONTAL PASSAGE. MORE
SUPPORT FOR GOING WARMER SO DID NUDGE UP TEMPERATURES A LITTLE BUT
NOT A LOT OF CONFIDENCE IN THIS DUE TO RECENT TEMPERATURE
PERFORMANCE.
NOT A LOT OF SURFACE CONVERGENCE WITH THIS WIND FIELD. PLUS ALL THE
MOISTURE LOOKS TO BE ABOVE 700 MB. SO WILL KEEP THIS PERIOD DRY.
SATURDAY NIGHT THROUGH WEDNESDAY...IN GENERAL THE MODELS ARE
CAPTURING THE OVERALL PATTERN. THE MODELS DROP A SYSTEM INTO THE
NORTH CENTRAL PORTION OF THE COUNTRY SUNDAY INTO MONDAY AND THEN
BRING THE UPPER TROUGH THROUGH AROUND TUESDAY AND THEN EAST OF THE
AREA. HOWEVER...THEY ARE DIFFERING ON THE TIMING OF THE NUMEROUS
SHORTWAVE TROUGHS THAT MOVE THROUGH IN THE WESTERLY FLOW ALOFT PRIOR
TO THE UPPER TROUGH MOVING THROUGH. THEY ALSO DIFFER IN HOW FAR SOUTH
AND HOW FAST THEY TAKE THE UPPER TROUGH THROUGH.
SO IN GENERAL THEY AGREE ON MAKING IT WET BUT NOT THE TIMING. THE
BIGGEST PROBLEM ON TIMING CENTERS AROUND TUESDAY. THE ECMWF TAKES
THE UPPER TROUGH THROUGH SOONER THAN THE GFS AND CANADIAN. SO DID
NOT HAVE ANY PROBLEM WITH WHAT THE CRH INIT GAVE ME WHICH IS
RAMPING UP POPS SUNDAY NIGHT WITH THE HIGHEST POPS MONDAY INTO
MONDAY NIGHT. FOR TUESDAY THE INIT GAVE ME POPS IN THE MIDDLE OF
THE TWO CAMPS AND COULD LIVE WITH THAT. AFTER TUESDAY IT LOOKS DRY.
STRONG COLD FRONT COMES THROUGH LATE SUNDAY NIGHT INTO EARLY MONDAY
MORNING. PER THIS RATHER FAST FRONTAL PASSAGE AND COLLABORATION
CHOSE TO LOWER MONDAY AND TUESDAY MAXES FROM WHAT THE CRH INIT GAVE
ME. OTHERWISE MADE NO OTHER CHANGES
THANKS TO ALL FOR THE COLLABORATION
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1054 PM MDT WED APR 17 2013
LIGHT SNOW AND IFR/MVFR CONDITIONS WILL CONTINUE AT KGLD AND KMCK
OVERNIGHT. CIGS AND VIS WILL IMPROVE THURSDAY MORNING BUT WIND WILL
REMAIN BREEZY TO WINDY. VFR CONDITONS SHOULD RETURN TO BOTH
TERMINALS IN THE AFTERNOON/EVENING AS THE UPPER TROUGH MOVES NORTHEAST OF
THE AREA.
&&
.CLIMATE...
ISSUED AT 330 AM MDT WED APR 17 2013
RECORD LOW HIGH TEMPERATURES IN JEOPARDY THURSDAY:
GOODLAND.....38 DEGREES
HILL CITY....47 DEGREES
MCCOOK.......35 DEGREES
BURLINGTON...35 DEGREES
YUMA.........36 DEGREES
COLBY........39 DEGREES
TRIBUNE......40 DEGREES
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY UNTIL 6 AM MDT /7 AM CDT/ THURSDAY FOR
KSZ001>004-013>016-027>029-041-042.
CO...WINTER WEATHER ADVISORY UNTIL 6 AM MDT THURSDAY FOR COZ090>092.
NE...WINTER WEATHER ADVISORY UNTIL 6 AM MDT /7 AM CDT/ THURSDAY FOR
NEZ079>081.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...FS
CLIMATE...JTL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1142 PM CDT WED APR 17 2013
...UPDATED SYNOPSIS SECTION...
.SYNOPSIS...
ISSUED AT 1140 PM CDT WED APR 17 2013
A STRONG MID TO UPPER LEVEL TROUGH OF LOW PRESSURE IS CURRENTLY
POSITIONED ACROSS THE CENTRAL AND NORTHERN ROCKIES WITH A MID TO
UPPER LEVEL RIDGE OF HIGH PRESSURE ACROSS THE SOUTHEAST UNITED
STATES. THIS PLACES WESTERN KANSAS UNDER SOUTHWEST FLOW ALOFT.
TOWARDS THE SURFACE, AN AREA OF LOW PRESSURE IS CURRENTLY LOCATED
ACROSS THE KS/MO BORDER WITH AN ASSOCIATED COLD FRONT STRETCHING
SOUTHWEST ACROSS OKLAHOMA. NORTHERLY WINDS ARE OBSERVED ACROSS THE
FORECAST AREA WITH MOSTLY CLOUDY SKIES. SHOWERS AND THUNDERSTORMS
CONTINUE ACROSS CENTRAL AND SOUTH CENTRAL KANSAS WITH LIGHTER
PRECIPITATION FALLING WEST OF THIS AREA. TEMPERATURES HAVE FALLEN
BELOW FREEZING ACROSS PORTIONS OF WEST CENTRAL AND SOUTHWEST
KANSAS ALLOWING A WINTRY MIX TO BE OBSERVED. RAIN, DRIZZLE,
FREEZING DRIZZLE, SLEET, SNOW, AND SMALL HAIL HAVE BEEN REPORTED
IN AREAS WEST OF HAYS TO MEADE LATE THIS EVENING. NO REPORTS OF
ACCUMULATION HAVE BEEN REPORTED AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 343 PM CDT WED APR 17 2013
THERE WILL BE A CONTINUED THREAT FOR SEVERE WEATHER OVER SOUTH
CENTRAL KANSAS THIS EVENING. THE NAM IS INDICATING THAT THE 850 MB
FRONTAL BOUNDARY WILL BE IN THE AREA FROM COLDWATER AND MEDICINE
LODGE TO ST JOHN THIS EVENING BEFORE SHIFTING SOUTH OF THE AREA BY
MIDNIGHT. RAP MODEL SOUNDINGS SHOW AROUND 1500 J/KG OF ELEVATED CAPE
IN THAT AREA. AS THE SOUTHWESTERN U.S. UPPER JET PROPAGATES EASTWARD
INTO THE SOUTHERN PLAINS THIS EVENING...INCREASING UPWARD VERTICAL
MOTION COULD AID IN THE DEVELOPMENT OF ADDITIONAL THUNDERSTORMS.
THERE WILL BE A THREAT FOR HAIL UP TO QUARTER SIZE IN THAT AREA.
THE UPPER TROUGH MOVES EAST OUT OVER THE HIGH PLAINS TONIGHT. MODEL
SOUNDINGS ARE INDICATING SATURATED CONDITIONS GENERALLY BELOW 700 MB
THROUGH THE NIGHT WITH THE LEVELS ABOVE 700 MB SATURATING FOR A 3-6
HOUR TIME FRAME DURING THE NIGHT. LOCATIONS FARTHER WEST ACROSS
WESTERN KANSAS WILL SEE AREAS OF DRIZZLE CONTINUING ALONG WITH A
CHANCE FOR RAIN SHOWERS. THERE WILL BE A TRANSITION FROM RAIN TO
SNOW WITH A PERIOD OF SLEET/FREEZING RAIN POSSIBLE IN BETWEEN. THE
ATMOSPHERE SHOULD COOL OFF ENOUGH FOR SNOW TO DEVELOP OVER WEST
CENTRAL KANSAS DURING THE EVENING HOURS WITH THIS SPREADING INTO
CENTRAL KANSAS AFTER MIDNIGHT. GIVEN THE SHORT WINDOW OF OPPORTUNITY
FOR THE SEEDER/FEEDER MECHANISM TO OCCUR...DO NOT EXPECT SNOW
AMOUNTS TO BE SIGNIFICANT WITH ONLY SOME LIGHT ACCUMULATIONS
POSSIBLE ON GRASSY AREAS. AM NOT ANTICIPATING ANY SIGNIFICANT ICE
ACCUMULATIONS TO OCCUR ALTHOUGH SOME ELEVATED SURFACES COULD GET
SOME LIGHT COATINGS.
AS COLD AIR ADVECTION INCREASES...STRONG NORTHERLY WINDS DEVELOP
OVER THE WESTERN HIGH PLAINS AND SPREAD EASTWARD TONIGHT. LOW LEVEL
WINDS THROUGH THE 850 MB LEVEL INCREASE TO 40-50 KNOTS OVERNIGHT
WHICH SHOULD SUPPORT WIND ADVISORY CRITERIA WINDS LATER TONIGHT INTO
THURSDAY MORNING. HAVE ISSUED A WIND ADVISORY FOR MIDNIGHT TONIGHT
UNTIL NOON THURSDAY FOR ALL OF SOUTHWEST AND CENTRAL KANSAS.
PRECIPITATION SHOULD BE WINDING DOWN FAIRLY QUICKLY LATE TONIGHT AND
THURSDAY MORNING AS THE UPPER SYSTEM MOVES EAST OF THE REGION.
CLOUDS SHOULD BE BREAKING UP FROM WEST TO EAST DURING THE DAY. WITH
SOME SUN...AFTERNOON HIGH TEMPERATURES MAY BE ABLE TO CLIMB INTO THE
LOWER 40S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 338 PM CDT WED APR 17 2013
FRIDAY:
UPPER LEVEL WNW FLOW WILL CONTINUE ON FRIDAY. AT THE SURFACE, HIGH
PRESSURE WILL RIDGE ACROSS THE PLAINS. NORTHWESTERLY WINDS WILL
EVENTUALLY BECOME SOUTHERLY AFTER SUNSET. HIGHS WILL BE IN THE 50S
AND LOWS WILL BE IN THE 20S. NO PRECIPITATION IS EXPECTED AS DRY
FLOW ALOFT AND LACK OF BL MOISTURE CONTINUES.
WEEKEND:
AN UPPER LEVEL TROUGH WILL DIG ACROSS THE CENTRAL AND SOUTHERN
ROCKIES THROUGH THE WEEKEND. THIS WILL PROMOTE A WARM AIR ADVECTION
PATTERN DOWNSTREAM ACROSS OUR REGION. A WARM 850 HPA PLUME WILL
ADVECT OFF THE ROCKIES AND OUT ACROSS SOUTHWEST KANSAS SATURDAY.
THIS WILL FAVOR DEEP MIXING AND HIGHS IN THE UPPER 60S TO LOWER 70S.
OVERNIGHT LOWS WILL MODERATE AS WELL WITH 30S ON SATURDAY AND 40S ON
SUNDAY. TEMPERATURES AROUND 70 DEG F CAN BE EXPECTED SUNDAY AS THE
AFOREMENTIONED WARM PLUME CONTINUES ACROSS THE REGION. THERE COULD BE
A FEW SHOWERS ACROSS SC/S KANSAS IN ASSOCIATION WITH WARM ADVECTION
BUT CONFIDENCE IS LOW AND MODELS ARE FAIRLY LIGHT ON QPF.
NEXT WEEK AND BEYOND:
A MAJOR CHANGE IN WEATHER IS POSSIBLE MONDAY OR TUESDAY. ANOTHER TROF
DIGGING OUT OF THE NORTHERN ROCKIES WILL USHER IN THE PASSAGE OF A
SIGNIFICANT COLD FRONT. THE ECMWF IS FAIRLY COLD WITH 850 HPA
TEMPERATURES DECREASING DOWN TO -6 DEG C. BOTH THE GFS AND ECMWF
INDICATE SOME LIGHT SNOWFALL ACROSS THE REGION ASSOCIATED WITH THIS
FRONT. CONFIDENCE IS LOW FOR PRECIPITATION TYPE BUT THERE IS HIGHER
CONFIDENCE IN LOWER TEMPERATURES WITH 40S AND 50S FOR HIGHS BY
TUESDAY/WEDNESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 659 PM CDT WED APR 17 2013
POOR AVIATION CONDITIONS WILL CONTINUE THROUGH THE NIGHT AS A
ROUND OF PRECIPITATION DEVELOPS THIS EVENING AND LINGERS THROUGH
THE OVERNIGHT HOURS. THE PRECIPITATION TYPE WILL BE RAIN AT GCK,
DDC, AND HYS THROUGH THE LATE EVENING...BUT A TRANSITION TO SLEET
AND/OR SNOW IS EXPECTED LATE THIS EVENING AND ESPECIALLY AFTER
MIDNIGHT. ONLY LIGHT PRECIPITATION IS EXPECTED, HOWEVER, AFTER
MIDNIGHT SO NO ACCUMULATION OF SIGNIFICANCE IS EXPECTED. STRONG
NORTH WINDS OF 25 OR MORE KNOTS WILL DEVELOP LATE AS THE MAIN
UPPER LEVEL STORM SYSTEM APPROACHES. IFR CEILINGS WILL PREVAIL AT
LEAST THROUGH THE MID MORNING HOURS THURSDAY...BUT GRADUALLY
SCATTERING OUT TO VFR CONDITIONS THEREAFTER AS THE STORM EXITS THE
WESTERN PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 27 38 24 59 / 70 10 0 0
GCK 27 37 22 60 / 60 10 0 0
EHA 26 39 23 60 / 40 10 0 0
LBL 28 41 23 60 / 50 10 0 0
HYS 28 36 23 58 / 80 30 0 0
P28 31 44 28 60 / 70 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL NOON CDT /11 AM MDT/ THURSDAY FOR KSZ030-031-
043>046-061>066-074>081-084>090.
&&
$$
SYNOPSIS...HOVORKA_42
SHORT TERM...GERARD
LONG TERM...SUGDEN
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
401 AM CDT THU APR 18 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT THU APR 18 2013
THE PV1.5 ANOMALY CURRENTLY ACROSS WRN KS HAS SPAWNED ANOTHER
LOCALLY STRONG BUT NARROW BAND OF MODERATE SNOW. THIS BAND OF
SNOW WILL MOVE WITH THE ANOMALY AND THE RUC LIFTS IT NORTH
NORTHEAST VERY QUICKLY THIS MORNING. ACCUMULATING SNOWFALL COULD
BE OUT OF THE FCST BY 15Z AND HIGHEST ACCUMULATIONS...PERHAPS 4
INCHES...SHOULD FOCUS ALONG AND EAST OF HIGHWAY 281 INCLUDING
CUSTER COUNTY.
IT IS CLEAR THE DRY AIR IS WINNING OUT ON THIS SYSTEM AS THE SNOW
HAS SHUT OFF WEST OF HIGHWAY 61 ACROSS WRN NEB. THE RAP IS
SUGGESTING SOME SNOW SHOWER ACTIVITY TODAY AS THE 500 MB COLD
POOL MOVES OVERHEAD...ESPECIALLY TO THE LEE OF THE BLACK HILLS
WHERE A CONVERGENCE ZONE COULD DEVELOP. THE MODELS DO NOT FCST
THE LOCATION OF CONVERGENCE VERY WELL BUT THE RAP...GEM REG AND
NAM ARE SUGGESTING THE PANHANDLE SOUTH SOUTHEAST OF CHADRON. THE
FCST TODAY JUST BROAD BRUSHES ISOLATED SNOW SHOWERS WEST BUT
TAPERS THE SNOW OFF IN THE NORTHEAST.
THE NAM AND RAP SHOW SKIES CLEARING AROUND NIGHTFALL TONIGHT. THE
ARCTIC HIGH WILL BUILD THROUGH THE CNTL ROCKIES TONIGHT WHILE LOW
PRESSURE SWIRLS ACROSS THE UPPER MIDWEST ALLOWING FOR WINDS TO
STAY UP A BIT. THIS MIGHT HOLD LOWS NEAR 20 AND RADIATIONAL
CONDITIONS WILL BE LESS THAN IDEAL.
THE SNOW FCST IS FOR 1 TO 3 INCHES OF NEW SNOW TODAY. THIS USES
THE RUC QPF BUT REDUCES IT BY 70 PERCENT IN MOST AREAS AND
APPLIES A 10 TO 1 RATIO. THIS IS THE SAME AS REDUCING THE QPF BY
50 PERCENT AND USING A 14 TO 1 RATIO WHICH MIGHT BE CLOSER TO
REAL LIFE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 359 AM CDT THU APR 18 2013
FRIDAY WILL SEE HIGHS REBOUND BACK INTO THE 40S...NEAR 50 FOR FAR
SW NEB. HOWEVER NORTHWEST FLOW WILL BRING A DISTURBANCE ACROSS THE
NORTHERN PLAINS. MODELS SHOW SOME DECENT LOW LEVEL
SATURATION...WITH DRY AIR ALOFT. COULD SEE SOME DRIZZLE OR
SPRINKLES DURING THE DAY...HOWEVER JUST NOT ENOUGH CONFIDENCE TO
ADD YET...MAINLY DUE TO CURRENT CONDITIONS ON THE DRIER SIDE.
SATURDAY AND SUNDAY THE COUPLE MORE OF QUICK MOVING DISTURBANCES
WILL RIDE ACROSS NORTHERN/CENTRAL PLAINS. BETTER ENERGY IS TO THE
NORTH...HOWEVER WILL SEE THE SOUTHERN EDGE MOVE ACROSS THE CWA.
EXPECTING TO CONTINUE TO SEE COLD AIR ALOFT SPREAD DOWN FROM
CANADA...HOWEVER LESS MOISTURE TO WORK WITH IN THE LOWER LEVELS.
STRONGER COLD FRONT SUNDAY WITH GFS DEVELOPING SOME MARGINAL
CAPE...COUPLE HUNDRED J/KG...AND BARELY NEG LI/S AHEAD OF THE
FRONT. HAVE INTRODUCED ISOLD THUNDER DURING THE DAY...WHICH MAY
LINGER INTO THE EVENING DEPENDING ON EXACT TIMING OF THE FRONT
AND MOISTURE.
MONDAY AND TUESDAY ARE EXPECTED TO BE ANOTHER WELL BELOW NORMAL
COUPLE OF DAYS. GFS CAME IN COOLER...WHICH IS CLOSER TO THE
COOLER EC. HIGHS LIKELY IN THE 40S...WHICH WOULD NORMALLY BE A
STRETCH TO GO SO FAR BELOW NORMAL /NORMAL IS 60S/ THIS FAR OUT.
HOWEVER WITH THE LAST TWO SYSTEMS SHOWING HOW EASY IT IS TO
ACCOMPLISH THIS APRIL...WILL CONTINUE TO BE SOME 20 PLUS DEGREES
BELOW NORMAL FOR HIGHS. LOWS IN THE 20S SO LIGHT PRECIP IS
EXPECTED TO BE RAIN OR A MIX DURING THE DAY AND A MIX TO SNOW
OVERNIGHT.
WEDNESDAY WILL SEE THE START OF ANOTHER WARMUP AND DRY
CONDITIONS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1227 AM CDT THU APR 18 2013
MIXED IFR/MVFR/VFR CONTINUES OVERNIGHT WITH IMPROVEMENT TO
VFR/MVFR FROM WEST TO EAST. THIS PROCESS IS ALREADY UNDERWAY
ACROSS WRN NEB. THE RAP IS SUGGESTING LOCAL IFR ACROSS WRN NEB
THURSDAY AFTERNOON AS SCATTERED -SHSN DEVELOP. EAST OF HIGHWAY
83...IFR/MVFR MAY CONTINUE THROUGH THURSDAY AFTERNOON IN SNOW AND
BLSN.
IMPROVEMENT TO WIDESPREAD VFR IS EXPECTED ALL AREAS BETWEEN 00Z
THURSDAY AND 06Z THURSDAY EVENING AS THE UPPER LEVEL LOW ACROSS
THE SRN ROCKIES EJECTS INTO THE MIDWEST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR
NEZ006>010-026>029-038.
&&
$$
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1253 AM CDT THU APR 18 2013
.SYNOPSIS...
ISSUED AT 256 PM CDT WED APR 17 2013
AT 19Z...WATER VAPOR IMAGERY CONTINUED SHOWING A DEEP TROUGH ACROSS
THE WESTERN STATES WITH THE AXIS RUNNING FROM LAKE WINNIPEG THROUGH
MONTANA...WYOMING AND UTAH TO SOUTHERN NEVADA. AT THE
SURFACE...THERE WAS A STRENGTHENING SURFACE LOW OVER CENTRAL NEW
MEXICO. A FRONT EXTENDED FROM THAT LOW ACROSS THE TEXAS RED RIVER
AREA THROUGH EASTERN OKLAHOMA AND SOUTHEAST KANSAS TO CENTRAL
MISSOURI. THERE WAS ALSO AND INVERTED TROUGH OR OCCLUDED FRONT
EXTENDING FROM THE NEW MEXICO LOW INTO SOUTH CENTRAL
COLORADO.
&&
.UPDATE...
ISSUED AT 1252 AM CDT THU APR 18 2013
DRY AIR HAS MADE RAPID PROGRESS THROUGH WESTERN NEB SO SEVERAL
COUNTIES CAN BE CLEARED FROM THE WINTER WEATHER ADVISORY. SNOW
SHOWER ACTIVITY IS EXPECTED OVERNIGHT THROUGH THURSDAY AFTN BUT
WIND SPEEDS AND SNOW ACCUMULATIONS WOULD NOT WARRANT AN ADVISORY.
UPDATE ISSUED AT 948 PM CDT WED APR 17 2013
A NEW FORECAST IS OUT USING THE RAP AND ARF MODELS. STILL LOOKS
LIKE AREAS EAST OF HIGHWAY 83 WILL MEASURE 3 TO 6 INCHES BY
THURSDAY AFTN. WEST OF 83...THE SNOW IS SHOWING SIGNS OF WINDING
DOWN. SATELLITE AND THE RAP MODEL SHOW TO DISTINCT AREAS OF
POTENTIAL VORTICITY. ONE NEAR DODGE CITY WHICH IS IGNITING
CONVECTION. SLEET AND SNOW SHOULD DEVELOP AS THIS AREA MOVES NORTH
NORTHEAST BRUSHING EASTERN ZONES WITH SNOW AFTER MIDNIGHT. MOST OF
THIS SNOW SHOULD END UP ACROSS CNTL NEB. THE SECOND AREA OF
POTENTIAL VORTICITY LIES ACROSS ERN NEW MEXICO. THIS ARE IS
EXPECTED TO IGNITE A SECOND BAND OF MODERATE SNOW ALONG AND EAST
OF HIGHWAY 83 LATE TONIGHT AND THURSDAY. MOST OF THIS SNOW SHOULD
FALL EAST OF HIGHWAY 83. THUS 2 TO 4 INCHES IS EXPECTED WEST OF
HIGHWAY 83 WITH THE EMPHASIS ON 2 INCHES GIVEN THE RADAR TRENDS
AND SIGNS OF DRY AIR WORKING SOUTHWARD THROUGH SOUTH DAKOTA.
WINDS ARE ABOUT 10 KTS LESS THAN PREVIOUSLY FORECAST BUT STRONGEST
WINDS COULD DEVELOP LATE THURSDAY MORNING AND AFTERNOON. THE REST
OF THE FORECAST IS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 256 PM CDT WED APR 17 2013
AREAS OF FREEZING DRIZZLE THIS MORNING LOOKS TO BE TRANSITIONING
MORE TO LIGHT FOG AND VERY LIGHT SNOW ACROSS THE CENTRAL SANDHILLS
AND EASTERN AREAS THIS AFTERNOON AS COLDER AIR CONTINUES TO SETTLE
SOUTHWARD. ONLY AREA WITH LIGHT SNOW ACCUMULATIONS THIS AFTERNOON IS
ACROSS SHERIDAN AND NORTHWEST CHERRY COUNTY.
THE 700MB CLOSED LOW WAS LOCATED IN CENTRAL COLORADO AT 18Z TODAY.
SNOW EXTENDS ACROSS THE COLORADO MOUNTAINS AND EASTERN FOOTHILLS
INTO SOUTHEAST WYOMING THE NEBRASKA PANHANDLE AND SOUTHWEST SOUTH
DAKOTA. MEANWHILE SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS
CENTRAL AND NORTHEAST KANSAS INTO FAR SOUTHEAST NEBRASKA SOUTHWEST
IOWA. STRONG STORMS DEVELOPING WEST CENTRAL OKLAHOMA/SOUTH CENTRAL
KANSAS. THE UPPER LOW IS FORECAST TO LIFT NORTHEAST AS A POSITIVELY
TILT INTO NORTHWEST KANSAS/CENTRAL NEBRASKA BY 06Z THURSDAY.
MODERATE TO LOCALLY HEAVY SNOW IS FAVORED TO DEVELOP ALONG AND WEST
OF THE UPPER LOW. THE GFS IS AND HAS CONSISTENTLY BEEN MORE ROBUST
WITH QPFS THE PAST SEVERAL RUNS...WHILE THE NAM HAS SLOWLY BEEN
COMING INTO LINE. ONE CONCERN WILL BE CONVECTION TO OUR SOUTHEAST
THIS AFTERNOON/TONIGHT WHICH MAY LIMIT MOISTURE TRANSPORT INTO
WESTERN NEBRASKA TONIGHT INTO THURSDAY. HAVE TAKEN THIS INTO ACCOUNT
WITH THE FORECAST. SECOND CONCERN WILL BE WINDS WITH NORTH WINDS
THIS EVENING 20 TO 35 MPH BACKING TO THE NORTHWEST AFTER MIDNIGHT.
THEN ON THURSDAY...NORTHWEST WINDS TO INCREASE TO 25 TO 35 MPH WITH
GUSTS TO 40 MPH. WINDS TONIGHT AND THURSDAY WILL CAUSE BLOWING AND
DRIFTING SNOW ACROSS THE SOUTHERN AND EASTERN HALF OF THE AREA
THROUGH THURSDAY. IN THE WINTER WEATHER ADVISORY AREA...SNOWFALL
AMOUNTS TONIGHT AND THURSDAY RANGE FROM 3 TO 5 INCHES SOUTHWEST
NEBRASKA...4 TO 7 INCHES EAST OF VALENTINE THROUGH BROKEN BOW.
ACROSS THE NORTHWEST AROUND 6 INCHES POSSIBLE. WILL CARRY ALL
EXISTING WINTER STORM WARNINGS AND ADVISORY THROUGH TONIGHT. ONLY
CHANGE WAS TO EXTEND THE ADVISORY THROUGH THE DAY THURSDAY ACROSS
THE EASTERN HALF OF THE FORECAST AREA DUE TO THE SLOWER TIMING OF
THE SYSTEM AND EXPECTED WRAP AROUND SNOW.
THE STRONG NORTHWEST WINDS WITH HIGH TEMPERATURES ONLY IN THE LOWER
30S MOST AREAS THURSDAY TO RESULT IN WIND CHILL VALUES OF 5 TO 15
ABOVE IN THE MORNING AND 15 TO 20 DEGREES IN THE AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 256 PM CDT WED APR 17 2013
WARM AIR RETURNING FROM THE SOUTHWEST FRIDAY EVENING WILL GENERATE
SOME DEEP ISENTROPIC UPGLIDE OF NEARLY SATURATED AIR IN THE 290-310K
LAYER. THE BOUNDARY LAYER IS PRETTY DRY THOUGH...SO SIGNIFICANT
PRECIPITATION IS NOT LIKELY.
A FRONT SETTLES INTO THE NORTHERN PLAINS SATURDAY AND THEN BEGINS
MOVING NORTH AND SOUTH ALTERNATELY. THIS WILL KEEP SOME CHANCE OF
PRECIPITATION IN CENTRAL AND WESTERN NEBRASKA SATURDAY EVENING
THROUGH TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1227 AM CDT THU APR 18 2013
MIXED IFR/MVFR/VFR CONTINUES OVERNIGHT WITH IMPROVEMENT TO
VFR/MVFR FROM WEST TO EAST. THIS PROCESS IS ALREADY UNDERWAY
ACROSS WRN NEB. THE RAP IS SUGGESTING LOCAL IFR ACROSS WRN NEB
THURSDAY AFTERNOON AS SCATTERED -SHSN DEVELOP. EAST OF HIGHWAY
83...IFR/MVFR MAY CONTINUE THROUGH THURSDAY AFTERNOON IN SNOW AND BLSN.
IMPROVEMENT TO WIDESPREAD VFR IS EXPECTED ALL AREAS BETWEEN 00Z
THURSDAY AND 06Z THURSDAY EVENING AS THE UPPER LEVEL LOW ACROSS
THE SRN ROCKIES EJECTS INTO THE MIDWEST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ THIS MORNING
FOR NEZ024-036-058-069-070.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR NEZ005-
025-037-059-071.
WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR
NEZ006>010-026>029-038.
&&
$$
UPDATE...CDC
SYNOPSIS...SPRINGER
SHORT TERM...ROBERG
LONG TERM...SPRINGER
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
948 PM CDT WED APR 17 2013
.SYNOPSIS...
ISSUED AT 256 PM CDT WED APR 17 2013
AT 19Z...WATER VAPOR IMAGERY CONTINUED SHOWING A DEEP TROUGH ACROSS
THE WESTERN STATES WITH THE AXIS RUNNING FROM LAKE WINNIPEG THROUGH
MONTANA...WYOMING AND UTAH TO SOUTHERN NEVADA. AT THE
SURFACE...THERE WAS A STRENGTHENING SURFACE LOW OVER CENTRAL NEW
MEXICO. A FRONT EXTENDED FROM THAT LOW ACROSS THE TEXAS RED RIVER
AREA THROUGH EASTERN OKLAHOMA AND SOUTHEAST KANSAS TO CENTRAL
MISSOURI. THERE WAS ALSO AND INVERTED TROUGH OR OCCLUDED FRONT
EXTENDING FROM THE NEW MEXICO LOW INTO SOUTH CENTRAL
COLORADO.
&&
.UPDATE...
ISSUED AT 948 PM CDT WED APR 17 2013
A NEW FORECAST IS OUT USING THE RAP AND ARF MODELS. STILL LOOKS
LIKE AREAS EAST OF HIGHWAY 83 WILL MEASURE 3 TO 6 INCHES BY
THURSDAY AFTN. WEST OF 83...THE SNOW IS SHOWING SIGNS OF WINDING
DOWN. SATELLITE AND THE RAP MODEL SHOW TO DISTINCT AREAS OF
POTENTIAL VORTICITY. ONE NEAR DODGE CITY WHICH IS IGNITING
CONVECTION. SLEET AND SNOW SHOULD DEVELOP AS THIS AREA MOVES NORTH
NORTHEAST BRUSHING EASTERN ZONES WITH SNOW AFTER MIDNIGHT. MOST OF
THIS SNOW SHOULD END UP ACROSS CNTL NEB. THE SECOND AREA OF
POTENTIAL VORTICITY LIES ACROSS ERN NEW MEXICO. THIS ARE IS
EXPECTED TO IGNITE A SECOND BAND OF MODERATE SNOW ALONG AND EAST
OF HIGHWAY 83 LATE TONIGHT AND THURSDAY. MOST OF THIS SNOW SHOULD
FALL EAST OF HIGHWAY 83. THUS 2 TO 4 INCHES IS EXPECTED WEST OF
HIGHWAY 83 WITH THE EMPHASIS ON 2 INCHES GIVEN THE RADAR TRENDS
AND SIGNS OF DRY AIR WORKING SOUTHWARD THROUGH SOUTH DAKOTA.
WINDS ARE ABOUT 10 KTS LESS THAN PREVIOUSLY FORECAST BUT STRONGEST
WINDS COULD DEVELOP LATE THURSDAY MORNING AND AFTERNOON. THE REST
OF THE FORECAST IS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 256 PM CDT WED APR 17 2013
AREAS OF FREEZING DRIZZLE THIS MORNING LOOKS TO BE TRANSITIONING
MORE TO LIGHT FOG AND VERY LIGHT SNOW ACROSS THE CENTRAL SANDHILLS
AND EASTERN AREAS THIS AFTERNOON AS COLDER AIR CONTINUES TO SETTLE
SOUTHWARD. ONLY AREA WITH LIGHT SNOW ACCUMULATIONS THIS AFTERNOON IS
ACROSS SHERIDAN AND NORTHWEST CHERRY COUNTY.
THE 700MB CLOSED LOW WAS LOCATED IN CENTRAL COLORADO AT 18Z TODAY.
SNOW EXTENDS ACROSS THE COLORADO MOUNTAINS AND EASTERN FOOTHILLS
INTO SOUTHEAST WYOMING THE NEBRASKA PANHANDLE AND SOUTHWEST SOUTH
DAKOTA. MEANWHILE SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS
CENTRAL AND NORTHEAST KANSAS INTO FAR SOUTHEAST NEBRASKA SOUTHWEST
IOWA. STRONG STORMS DEVELOPING WEST CENTRAL OKLAHOMA/SOUTH CENTRAL
KANSAS. THE UPPER LOW IS FORECAST TO LIFT NORTHEAST AS A POSITIVELY
TILT INTO NORTHWEST KANSAS/CENTRAL NEBRASKA BY 06Z THURSDAY.
MODERATE TO LOCALLY HEAVY SNOW IS FAVORED TO DEVELOP ALONG AND WEST
OF THE UPPER LOW. THE GFS IS AND HAS CONSISTENTLY BEEN MORE ROBUST
WITH QPFS THE PAST SEVERAL RUNS...WHILE THE NAM HAS SLOWLY BEEN
COMING INTO LINE. ONE CONCERN WILL BE CONVECTION TO OUR SOUTHEAST
THIS AFTERNOON/TONIGHT WHICH MAY LIMIT MOISTURE TRANSPORT INTO
WESTERN NEBRASKA TONIGHT INTO THURSDAY. HAVE TAKEN THIS INTO ACCOUNT
WITH THE FORECAST. SECOND CONCERN WILL BE WINDS WITH NORTH WINDS
THIS EVENING 20 TO 35 MPH BACKING TO THE NORTHWEST AFTER MIDNIGHT.
THEN ON THURSDAY...NORTHWEST WINDS TO INCREASE TO 25 TO 35 MPH WITH
GUSTS TO 40 MPH. WINDS TONIGHT AND THURSDAY WILL CAUSE BLOWING AND
DRIFTING SNOW ACROSS THE SOUTHERN AND EASTERN HALF OF THE AREA
THROUGH THURSDAY. IN THE WINTER WEATHER ADVISORY AREA...SNOWFALL
AMOUNTS TONIGHT AND THURSDAY RANGE FROM 3 TO 5 INCHES SOUTHWEST
NEBRASKA...4 TO 7 INCHES EAST OF VALENTINE THROUGH BROKEN BOW.
ACROSS THE NORTHWEST AROUND 6 INCHES POSSIBLE. WILL CARRY ALL
EXISTING WINTER STORM WARNINGS AND ADVISORY THROUGH TONIGHT. ONLY
CHANGE WAS TO EXTEND THE ADVISORY THROUGH THE DAY THURSDAY ACROSS
THE EASTERN HALF OF THE FORECAST AREA DUE TO THE SLOWER TIMING OF
THE SYSTEM AND EXPECTED WRAP AROUND SNOW.
THE STRONG NORTHWEST WINDS WITH HIGH TEMPERATURES ONLY IN THE LOWER
30S MOST AREAS THURSDAY TO RESULT IN WIND CHILL VALUES OF 5 TO 15
ABOVE IN THE MORNING AND 15 TO 20 DEGREES IN THE AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 256 PM CDT WED APR 17 2013
WARM AIR RETURNING FROM THE SOUTHWEST FRIDAY EVENING WILL GENERATE
SOME DEEP ISENTROPIC UPGLIDE OF NEARLY SATURATED AIR IN THE 290-310K
LAYER. THE BOUNDARY LAYER IS PRETTY DRY THOUGH...SO SIGNIFICANT
PRECIPITATION IS NOT LIKELY.
A FRONT SETTLES INTO THE NORTHERN PLAINS SATURDAY AND THEN BEGINS
MOVING NORTH AND SOUTH ALTERNATELY. THIS WILL KEEP SOME CHANCE OF
PRECIPITATION IN CENTRAL AND WESTERN NEBRASKA SATURDAY EVENING
THROUGH TUESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 623 PM CDT WED APR 17 2013
MVFR/IFR CONTINUES TONIGHT IN FREEZING RAIN...SLEET AND SNOW. THE
FORECAST MODELS SUGGEST A GRADUAL CEILING IMPROVEMENT ALONG AND
WEST OF HIGHWAY 83 AFTER 18Z THURSDAY. THUS MVFR AND VFR CIGS
COULD DEVELOP WEST OF 83 TOMARROW AFTN. EAST OF 83...MVFR/IFR IS
EXPECTED TO CONTINUE THROUGHOUT THE DAY THURSDAY IN SNOW AND
BLOWING SNOW.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ THURSDAY FOR
NEZ004-022>024-035-036-056>058-069-070-094.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THURSDAY FOR NEZ005-025-
037-059-071.
WINTER WEATHER ADVISORY UNTIL 7 PM CDT THURSDAY FOR NEZ006>010-
026>029-038.
&&
$$
UPDATE...CDC
SYNOPSIS...SPRINGER
SHORT TERM...ROBERG
LONG TERM...SPRINGER
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
943 PM MDT WED APR 17 2013
.UPDATE...
EXPIRED THE WIND RELATED NPW PRODUCTS ON SCHEDULE AND CANCELLED
THE EAST CENTRAL ZONES WIND ADVISORY THAT WAS OUT ALL NIGHT...
THOUGH THE LATTER IS A RATHER CLOSE CALL FOR THE CLOVIS AREA AS
THAT OBSERVATION OFTEN SEEMS AT THE HIGH END OF WIND SPEEDS
COMPARED TO SURROUNDING AREAS. STILL DO NOT BELIEVE ADVISORY LVL
SPEEDS WILL BE REPRESENTATIVE FOR THE MAJORITY OF THOSE CANCELLED
COUNTIES. HAVE SOME CONCERN FOR HOW LONG DURATION OF FREEZING
TEMPS WILL BE LATE TONIGHT FOR MOST OF THE FREEZE WARNING ZONES AS
EITHER CLOUDS OR WIND MAY HOLD THEM UP A BIT HIGHER THAN EARLIER
EXPECTED...SO IT MAY BE RATHER MARGINAL FOR TONIGHT. KEPT THE
HIGHLIGHTS GOING HOWEVER AS RECENT WARMTH WILL LIKELY HAVE LURED
SOME GARDENERS TO PLANT SENSITIVE PLANTS ALREADY. AS FOR SNOW
ADVISORY...IT APPEARS THAT EXPIRATION TIME IS OUT TOO LONG IN
TIME...ESPECIALLY FOR HARDING AND UNION COUNTIES. TEMPS GETTING
BACK WELL ABOVE FREEZING...LESSENING UPSLOPE FLOW AND EVEN MORE
LIMITED MOISTURE AND DYNAMICS WITH NEXT FOLLOWUP DISTURBANCE IN NW
FLOW WOULD ARGUE FOR SIGNIFICANTLY EARLIER EXPIRATION TIME...AND
EVEN THE NORTHERN MTN ZONES WILL LIKELY SEE JUST OFF AND ON SNOW
SHOWERS THAT WILL NOT ACCUM MUCH IF AT ALL GIVEN THAT IT IS THIS
LATE IN APRIL AND THERE WOULD BE SOME MELTING OF ANY MINOR ACCUM.
ANY SNOW SHOWERS WOULD BRING. NONETHELESS...AM DEFERRING TO
MIDNIGHT CREW TO MAKE THAT DETERMINATION GIVEN LATEST MODEL AND
OTHER INDICATIONS.
43
&&
.PREV DISCUSSION...536 PM MDT WED APR 17 2013...
.AVIATION...
00Z TAF CYCLE
LOW CLOUDS WILL SURGE SOUTH AGAIN TONIGHT AS A POTENT BACK DOOR
COLD FRONT SURGES INTO THE EASTERN PLAINS. LATEST RUC AND NAM
SOLUTIONS INDICATE LOW CLOUDS NEAR 015 WILL MAKE IT BACK INTO
KTCC AND SATELLITE CONFIRMS...SO HAVE ADDED BKN CIGS THERE FOR
SEVERAL HOURS TONIGHT. SOME LIGHT PRECIP MAY DEVELOP BEHIND THE
FRONT AS WELL HOWEVER LEFT OUT SINCE CONFIDENCE NOT AS HIGH.
MODELS BOTH AGREE AS WELL WITH FRONT PUSHING INTO KROW WITH A
SCT TO BKN DECK BUT NOT NEARLY AS CONFIDENCE THERE SO LEFT SCT
DECK FOR NOW. ELSEWHERE...WINDS AND BLDU WILL TAPER OFF THIS
EVENING. PRECIP WILL BECOME TERRAIN DOMINATED OVER THE NORTH
WHERE A COUPLE INCHES OF SNOW AND IFR CIGS WILL OCCUR. THE MAIN
IMPACT AREA FOR SNOW WILL BE THE NE PLAINS FROM RATON EAST TO
CLAYTON. SKIES WILL CLEAR THURSDAY FROM WEST TO EAST...EXCEPT
FOR THE NE CORNER WHERE MODELS CONTINUE TO INDICATE SOME LIGHT
PRECIP PUSHING EAST OFF THE HIGH TERRAIN. GUYER
.PREV DISCUSSION...330 PM MDT WED APR 17 2013...
PLETHORA OF HIGHLIGHTS OUT SO WILL KEEP THIS SHORT. UPPER LEVEL
LOW/TROUGH NEAR THE FOUR CORNERS EARLY THIS AFTERNOON. RELATIVELY
MOIST SOUTHWEST FLOW ALOFT CONTINUING TO BRING OCCASIONAL LIGHT
TO MODERATE SNOW TO PORTIONS OF THE NORTHERN MOUNTAINS. LIGHT
ACCUMULATION REPORTED IN CHAMA AND DULCE BY LATE THIS MORNING WITH
LIGHT SNOW AND A TRACE OF ACCUMULATION AT ANGEL FIRE. BACKDOOR FRONT
REMAINED NEARLY STATIONARY TODAY...FROM NEAR A TRINIDAD TO RATON
TO TUCUMCARI LINE. APPROXIMATELY A 40F DIFFERENCE BETWEEN THE
AIRMASS TO THE NORTH OF THE FRONT OVER NE NM AND THE AIRMASS OVER
SE NM. UPPER LOW/TROUGH WILL CONTINUE TO SLOWLY TRANSLATE EWD THIS
EVENING...WITH THE TROUGH AXIS LOCATED ALONG INTERSTATE 25 OR SO BY
AROUND MIDNIGHT. NAM AND GFS IN GOOD AGREEMENT THAT AS THE 700MB
WAVE CROSSES THE ROCKIES EARLY THIS EVENING...THE MID LEVEL FLOW
TURNS NORTHERLY AND THE COLD AIR OVER ERN COLORADO/BACKDOOR FRONT
SURGES SOUTHWARD OVERNIGHT. DECIDED TO INCLUDE THE FAR NE
HIGHLANDS...UNION AND HARDING COUNTIES IN THE WINTER WEATHER
ADVISORY OVERNIGHT. 12Z NAM12 HITTING THIS AREA QUITE HARD WITH
SNOW THIS EVENING AND WITH VISIBLE SATELLITE IMAGERY SHOWING SIGNS
OF STRONG FRONTOGENETIC FORCING ALONG WITH MID-LEVEL INSTABILITY OVER NE
NM/SE CO STARTING TO TAKE SHAPE.
UPPER LEVEL TROUGH SLOW TO SHIFT EWD THURSDAY WITH ONE LAST SPEED
MAX TO ROUND THE BASE OF THE TROUGH. SURFACE CONVERGENCE ALONG
WITH COLD AIR ALOFT WILL LEAD TO SCATTERED SNOW SHOWERS FOR THE
NORTHERN MOUNTAINS DURING THE AFTERNOON.
DRY NW FLOW ALOFT TRANSITIONS OVERHEAD THURSDAY NIGHT AND FRIDAY.
WARMING TREND GETS UNDERWAY AREA-WIDE FRIDAY WITH TEMPERATURES
STARTING TO AT LEAST APPROACH AVERAGE LEVELS. THE WARMING TREND
CONTINUES INTO THE WEEKEND...ALBEIT A WEAK SHORT-WAVE CLIPS THE
FAR NORTH/NE PART OF THE STATE SLOWING THE WARMING TREND THERE
WITH A SLIGHT CHANCE FOR A LIGHT MOUNTAIN SHOWER. MEDIUM RANGE
GLOBAL MODELS SEEM TO BE SETTLING ON TIMING AND PLACEMENT OF THE
NEXT COLD UPPER LEVEL TROUGH AND UNSEASONABLY STRONG BACK DOOR
COLD FRONT FOR EARLY NEXT WEEK. 33
.FIRE WEATHER...
STRONG SURFACE WINDS AND RELATIVE HUMIDITY BELOW 15 PERCENT WILL
CONTINUE TO PRODUCE RED FLAG CONDITIONS THROUGH MID EVENING ACROSS
ZONES 106...107 AND 108. STRONGEST WINDS WILL DIMINISH AFTER THAT
TIME AND LESSEN THE FIRE WEATHER CONDITIONS. BASE OF UPPER LEVEL LOW
WILL MOVE ACROSS NORTHERN NM TONIGHT...WHILE A COLD FRONT PUSHES
SOUTHWARD ACROSS EASTERN NM. THESE TWO SYSTEMS WILL PRODUCE LIGHT TO
OCCASIONALLY MODERATE SNOWFALL ACROSS THE NORTHERN SANGRE DE
CRISTOS...THE NORTHERN HIGHLANDS AND THE FAR NORTHEASTERN PLAINS.
WETTING PRECIPITATION IS LIKELY ACROSS THESE AREAS TONIGHT.
INCREASING LOW LEVEL MOISTURE TONIGHT WILL PRODUCE VERY GOOD TO
EXCELLENT RECOVERIES ACROSS THE NORTHERN MOUNTAINS AND EASTERN
PLAINS. FAIR TO GOOD OVERNIGHT RECOVERIES ARE EXPECTED ACROSS THE
REMAINDER OF THE REGION. WINDS WILL DROP BELOW 15 MPH ACROSS MOST OF
THE REGION AFTER MIDNIGHT...EXCEPT BEHIND THE COLD FRONT IN THE
EASTERN PLAINS. A WIND ADVISORY WILL REMAIN IN EFFECT ACROSS THE
EASTERN PLAINS THROUGH DAWN THURSDAY WITH NORTH TO NORTHEAST WINDS
GREATER THAN 30 MPH.
AS THE UPPER LOW MOVES AWAY FROM NM INTO THE U.S. CENTRAL PLAINS
THURSDAY...A DEEP NORTHWEST FLOW WILL SET UP ACROSS THE STATE.
NORTHWEST WIND WEST OF THE DIVIDE WILL GUST TO 30 MPH IN THE
AFTERNOON...BUT RELATIVE HUMIDITY WILL REMAIN ABOVE CRITICAL VALUES.
RELATIVE HUMIDITY ACROSS THE SOUTHERN ZONES WILL DIP BRIEFLY BELOW
15 PERCENT...BUT WIND SPEEDS AND GUSTS ACROSS THIS AREA WILL BE
LIGHTER. VENTILATION THURSDAY WILL BE VERY GOOD WEST OF THE DIVIDE
AND GOOD EAST OF THE DIVIDE.
SURFACE HIGH PRESSURE TO THE NORTH WILL BEGIN TO BUILD SOUTHWARD
ACROSS NM THURSDAY NIGHT...AND LIGHT NORTH TO NORTHWEST WINDS ARE
EXPECTED. EXPECT INVERSIONS TO DEVELOP IN THE VALLEY AND LOW-LYING
AREAS LATE THURSDAY NIGHT. RECOVERIES WILL BE FAIR TO GOOD IN MOST
LOCATIONS AND WILL BE VERY GOOD TO EXCELLENT ACROSS NORTHERN NM.
WEAK HIGH PRESSURE ALOFT AND MODERATE SURFACE HIGH PRESSURE WILL
BUILD ACROSS NM FRIDAY. THIS WEATHER PATTERN WILL PRODUCE LIGHT
WINDS FOR THE ENTIRE REGION WITH GUSTS GENERALLY LESS THAN 20 MPH IN
THE AFTERNOON. MORNING INVERSIONS WILL BE SLOW TO BURN OFF
FRIDAY...ESPECIALLY WEST OF THE DIVIDE. SIGNIFICANTLY DRIER AIR WILL
MOVE ACROSS NM FROM THE WEST FRIDAY. THIS AIR MASS WILL CAUSE
AFTERNOON RELATIVE HUMIDITY TO FALL BELOW 15 PERCENT IN MOST
LOCATIONS...EXCEPT IN THE NORTHERN MOUNTAINS. VENTILATION WILL BE
POOR TO FAIR DURING THE MORNING HOURS...AND THEN IMPROVE TO GOOD TO
VERY GOOD IN THE AFTERNOON.
DRY AIR MASS WILL REMAIN IN PLACE ACROSS NM FRIDAY NIGHT. OVERNIGHT
RELATIVE HUMIDITY RECOVERIES WILL BE POOR TO FAIR...EXCEPT IN THE
NORTHERN MOUNTAINS...WHERE RECOVERIES ARE EXPECTED TO BE GOOD. WINDS
WILL BE LIGHT WEST OF THE DIVIDE FRIDAY NIGHT. SURFACE LOW PRESSURE
FORMING IN EASTERN CO FRIDAY NIGHT WILL GENERATE LIGHT TO MODERATE
SOUTH TO SOUTHEAST WINDS IN THE EASTERN PLAINS. RECOVERIES WILL BE
POOR ACROSS SOUTH CENTRAL ZONES AND FAIR ELSEWHERE.
A COMBINATION OF DEVELOPING SURFACE LOW PRESSURE ACROSS WESTERN TX
AND STRENGTHENING WINDS ALOFT SATURDAY WILL AN INCREASE IN WIND
SPEEDS EAST OF THE DIVIDE. AFTERNOON WINDS EAST OF THE DIVIDE WILL
GUST UP TO 35 MPH IN THE AFTERNOON HOURS. LOW RELATIVE HUMIDITY AND
GUSTY WINDS HAVE THE POTENTIAL TO CREATE 3 TO 5 HOURS OF NEAR
CRITICAL FIRE WEATHER CONDITIONS ALONG I-40 FROM CLINES CORNERS TO
SANTA ROSA SATURDAY AFTERNOON. VENTILATION WILL BE FAIR TO GOOD IN
THE MORNING HOURS AND RAPIDLY IMPROVE IN THE EARLY AFTERNOON TO
BECOME EXCELLENT ACROSS ALL OF NM.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
HARD FREEZE WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING FOR
THE FOLLOWING ZONES...NMZ519-520-530>538.
FREEZE WARNING FROM 2 AM TO 10 AM MDT THURSDAY FOR THE FOLLOWING
ZONES...NMZ519-520-534>536.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT THURSDAY FOR THE FOLLOWING
ZONES...NMZ510-512>515-527-528-530-531.
&&
$$
43
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
143 AM EDT THU APR 18 2013
.SYNOPSIS...
A POTENT SPRING STORM SYSTEM WILL EJECT NORTHEAST THROUGH THE MID
MISSISSIPPI VALLEY TONIGHT THROUGH FRIDAY...BRINGING A WILD SWING
IN TEMPERATURE AND THE THREAT OF STRONG TO SEVERE THUNDERSTORMS.
VERY WARM CONDITIONS ON THURSDAY WITH GUSTY SOUTH WINDS WILL BE
FOLLOWED BY EVEN GUSTIER NORTHWEST WINDS AND TEMPERATURES SOME 30
DEGREES LOWER THAN THAN ON THURSDAY. IN THE WAKE OF THIS
SYSTEM...COOL CANADIAN HIGH PRESSURE WILL SETTLE INTO THE OHIO
VALLEY FOR THE WEEKEND WITH THE THREAT OF MORNING FROST AND SOME
DRY WEATHER.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
WARM FRONTAL BOUNDARY WILL CONTINUE TO LIFT NORTH THROUGH THE
OVERNIGHT HOURS. MOST LOCATIONS WILL REMAIN DRY THROUGH THE
OVERNIGHT HOURS HOWEVER A FEW ISOLATED STORMS MAY REACH INTO NW
PORTIONS OF THE FA ACROSS EAST CENTRAL INDIANA AND WEST CENTRAL
OHIO. WITH THE FRONT LIFTING NORTH WENT ON THE WARMER SIDE OF
GUIDANCE OR WARMER THAN GUIDANCE WITH LOW TEMPERATURES OVERNIGHT.
WINDS WILL STAY UP SOME THROUGH THE OVERNIGHT HOURS WITH A FEW
WIND GUSTS POSSIBLE AS WELL HOWEVER THE HIGHER WIND GUSTS WILL
HOLD OFF UNTIL AFTER SUNRISE ACROSS THE FA.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
FOUND MODEL AGREEMENT TO BE VERY STRONG THROUGH THIS PERIOD AND
GOING FORECAST HAD LARGELY CAPTURED THE ENTIRE FCST SCENARIO
EXTREMELY WELL...THUS CHANGES WERE REALLY FOCUSED ON DETAILS OF
WINDS/TIMING OF STORMS...AND TIGHTENING UP GRADIENTS AHEAD/BEHIND
THE EXPECTED COLD FRONT TOMORROW NIGHT.
AFTERNOON GOES WATER VAPOR IMAGERY AND RAP ANALYSIS INDICATED A
VERY DYNAMIC AND COLD LONGWAVE TROUGH /-30C AT 500MB NEAR SLC AT
12Z/ OVER THE INTERMOUNTAIN WEST WITH SEVERAL IMPRESSIVE
CONVECTIVE COMPLEXES DOWNSTREAM NEAR THE ATTENDANT FRONTAL
SYSTEMS OVER THE MID MS VALLEY. HEIGHTS HAVE BEEN RISING OVER THE
OHIO VALLEY MUCH OF THE DAY BUT THAT PROCESS WILL TURN AROUND AS A
STRONG SHORTWAVE TROUGH/UPPER JET DIGS THROUGH THE LONGWAVE TROUGH
AND EJECTS INTO THE CENTRAL PLAINS...LOWERING HEIGHTS DOWNSTREAM
OVER THE OHIO VALLEY AND ALLOWING A STRONG COLD FRONT AND LOW
PRESSURE TO FURTHER ORGANIZE AND PUSH EAST TOWARD THE AREA.
POOL OF VERY WARM /+15C AT H85/ AIR JUST TO OUR SOUTHWEST WILL
LIFT NORTHWARD AS WARM MENTIONED ABOVE CONTINUES NORTH AND DEEPER
SLY FLOW IS ATTAINED. AS DYNAMICS REALLY BEGIN TO INCREASE ON
THURSDAY MORNING...LOW LEVEL WIND FIELD AND FALLING PRESSURES TO
THE WEST WILL INDUCE A POTENT WARM ADVECTION REGIME...WITH
EFFICIENT MIXING UNDER PARTLY CLOUDY SKIES. NAM/GFS SFC PRESSURE
GRADIENT MAGNITUDES AND SOUNDING ANALYSIS VALID THURS AFTN
SUGGESTS A WINDY DAY...SUSTAINED 20 TO 30 MPH WITH GUSTS TO 40
MPH...ESPECIALLY WEST OF I-71 FROM 10 AM THROUGH THE AFTN. A
LITTLE CONCERNED FOR WIND ADVISORY CONDITIONS IN OUR FAR NORTHWEST
WHICH IS A WIND PRONE AREA AND WILL BE UNDER THE STRONGEST
INFLUENCE OF THE DEVELOPING/DEEPENING SFC-850MB CYCLONE AND
ATTENDANT LOW LEVEL JET. WILL CONTINUE TO HIGHLIGHT WIND THREAT ON
HWO. MAX TEMPS SHOULD WARM CONSIDERABLY...INTO THE 80S MOST AREAS
AND WITH A MORE SELY TRAJECTORY OVER OUR EAST...THIS IS
DOWNSLOPE/DRYING OFF THE APPALACHIAN RISE AND MAY ALLOW BETTER
DEW POINT REDUCTION/WARMING. LIKELY WILL FALL A FEW DEGREES SHORT
OF RECORDS...WHICH ARE IN THE MID/UPPER 80S.
GETS VERY INTERESTING THURSDAY AFTER ABOUT 5 PM WHEN STRONG DEEP
LAYERED ASCENT AND LOW LEVEL CONVERGENCE IN VICINITY OF FRONTAL
ZONE TO THE WEST SHOULD CONTINUE TO FOSTER DEVELOPMENT OF A VERY
LONG/STRONG SQUALL LINE. THERE/S BEEN HINTS IN THE HIGHER RES
CONVECTION ALLOWING DATA THAT A FEW DISCRETE CELLS MAY FORM IN THE
WARM SECTOR OVER OUR FAR WEST LATE AFTN/EARLY EVENING AND THAT
WOULD BE PROBLEMATIC GIVEN A WEAK MLCINH FIELD /ERODED CAP/ AND
MLCAPE AROUND 1500 J/KG AMIDST VERY STRONG FLOW /SHEAR/. RIGHT NOW
AM NOT SEEING A STRONG/CONSISTENT SIGNAL THERE...SO KEEPING RAIN
CHANCES LOW THROUGH THE DAY.
AS THE EVENING WEARS ON...ADVANCING FRONTAL ZONE /OR PREFRONTAL
TROUGH/ WILL BECOME FOCUS FOR CONTINUED ADVANCEMENT AND
DEVELOPMENT OF CONVECTIVE SQUALL LINE INTO THE WFO ILN AREA
SOMETIME BETWEEN 10 PM AND 2 AM. THINK LATEST SWODY2 FROM SPC IS
REALISTIC...THAT WFO ILN WRN CWA WILL BE A TRANSITION AREA FROM A
VERY POTENT QLCS WITH SEVERE THREAT...TO A NON-LIGHTNING PRODUCING
LINE OF RAIN OR SHOWERS LATE IN THE NIGHT INTO THE EARLY MORNING HOURS ON
FRIDAY.
CLEARLY THE HIGHEST THREATS LOCALLY OF WIND ARE IN OUR FAR WEST
BEFORE CONVECTION ENTRAINS AN INCREASINGLY HOSTILE LOW LEVEL
AIRMASS /REF ABOVE COMMENT ABOUT DRYING ON SOUTH-SELY FLOW INTO ERN
AREAS/...AND SOUNDING ANALYSIS FROM A MULTITUDE OF NWP SOURCES
INDICATES ANY SURFACE BASED/NEAR SURFACE BASED INSTBY WILL BE
MINIMAL AT BEST /100 J/KG/ WEST OF I-75. PRIOR NOCTURNAL QLCS
EVENTS HOWEVER SUGGEST MLCAPE/MUCAPE IN THESE STRONGLY FORCED
EVENTS IS OVERRATED TO A DEGREE...AND GIVEN THE EXPECTED 0-1KM
SHEAR TOWARD 50KTS...THE SHAPE/ORIENTATION OF THE LOWEST 1KM TEMP
TRACE IS VERY IMPORTANT FOR QLCS COUPLETS AND/OR DAMAGING WIND
TRANSPORT TO THE SURFACE. FCST SOUNDINGS ARE HARD TO BUY INTO
GIVEN FICKLE NATURE OF BOUNDARY LAYER RESOLUTION IN NWP...BUT
ISOTHERMAL TO WEAKLY NEGATIVE LAPSE RATES INDEED SUGGESTS WE MAY
VERY WELL HAVE A THREAT FOR DAMAGING GUSTS ESP IN THE FIRST COUPLE
OF HOURS OF THE EVENT WEST OF I-75. WITH TIME...BUOYANCY REALLY
TANKS AND EXPECT THIS CONVECTIVE SYSTEM TO STRUGGLE TO OR NOT
PRODUCE LIGHTNING OVER THE ERN 1/2 OF THE FORECAST AREA LATE IN
THE NIGHT AND FRIDAY MORNING.
ALSO...WHILE WINDS MAY DECREASE EARLY IN THE EVENING...ISALLOBARIC
COMPONENT IMMEDIATELY IN ADVANCE OF THE VERY SHARP/STRONG FRONAL
ZONE WILL PROBABLY ALLOW FOR A BRIEF/RAPID INCREASE IN SUSTAINED
AND GUSTS IMMEDIATELY AHEAD OF THE SQUALL LINE.
FOR FLOOD CONCERN...SYSTEM WILL BE PROGRESSIVE AND HAVE HIGH
CONFIDENCE IN RAIN AMOUNTS REMAINING LESS THAN AN INCH IN MOST
AREAS. HEAVIEST WEST...LIGHTEST EAST. FEEL ANY FLOODING ISSUES
WOULD BE BRIEF/NUISANCE AND TIED TO AREAS OF VERY MOIST SOILS FROM
MERCER INTO HARDIN/DELAWARE COUNTIES.
FRIDAY TO BE POLAR OPPOSITE OF THURSDAY...A 30 DEGREE TEMP CHANGE
/PERHAPS MORE IN THE WEST/ FROM DAYTIME MAX TO DAYTIME MAX...WITH
MORE GUSTY WINDS AND A RAPID END TO THE RAIN WITH DRY SLOT. THINK
WIND ADVISORY MAY BECOME LIKELY IN NORTH/WEST AT SOME POINT AS SFC
CYCLONE REACHES LOWEST PRESSURES /SUB-990MB/ OVER LAKE SUPERIOR. A
VERY CHILLY/MISERABLE DAY IN COMPARISON TO THURSDAY.
ENOUGH WEAKENING IN THE MSLP GRADIENT FRIDAY NIGHT AND POTENTIAL
CLEARING TO WARRANT INSERT OF PATCHY FROST...THOUGH FOLLOWING
NIGHT LOOKS EVEN BETTER FOR FROST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A STRONG AREA OF HIGH PRESSURE WILL BUILD IN THE MID SECTION OF THE
COUNTRY ON SATURDAY AND NOSE INTO THE GREAT LAKES AND OHIO VALLEY
REGION BY EVENING. SOUTHEAST FLOW WILL THEN GRADUALLY TURN SOUTH
AHEAD OF THE NEXT COLD FRONT EXPECTED TO MOVE THROUGH LATE IN THE
FORECAST PERIOD.
MODELS ARE IN A WIDE RANGE FOR TIMING FOR THE TUESDAY/WEDNESDAY
SYSTEM. THE PREVIOUS FORECAST APPEARS TO HAVE THE BEST INITIAL
CONDITIONS BUT SOME NEIGHBORING OFFICES APPEAR HIGHER THAN I AM
WILLING TO GO WITH RAIN CHANCES OVERNIGHT TUESDAY. GIVEN THE LATEST
EUROPEAN WHICH SPINS THE SYSTEM UP IN THE MIDWEST ON TUESDAY...IT
HAS A MUCH SLOWER AND MORE DEVELOPED SYSTEM THAN THE GFS WHICH IS
INDICATING AN OPEN WAVE YET STRONG COLD FRONTAL PASSAGE EARLY
WEDNESDAY. WPC HAS THIS FRONT ON THE OTHER SIDE OF THE APPALACHIANS
AT THIS TIME WHICH APPEARS INCONSISTENT WITH THE REST OF THE
GUIDANCE I SEE.
UNTIL THE RAIN HITS WITH THE NEXT SYSTEM DAYS 6/7...TEMPERATURES
WILL BE ON THE INCREASE AND START FROM A COOLER 50S ON SATURDAY WITH
OVERNIGHT LOWS LIKELY NEEDING FROST HEADLINES. BY THIS TIME NEXT
WEEK AHEAD OF THE COLD FRONT...70S WILL BE FOUND AGAIN WITH
OVERNIGHT LOWS IN THE 50S. HAVE GONE WARMER THAN GUIDANCE AHEAD OF
THE NEXT SYSTEM BUT FEEL THAT THE FORECAST WILL CONTINUE TO BE
ADJUSTED UPWARD A LITTLE BIT EACH DAY.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A WARM FRONT WILL CONTINUE TO MOVE NORTH TOWARD THE GREAT LAKES
REGION THIS MORNING. POTENT UPPER LEVEL TROUGH WILL MOVE INTO THE
PLAINS TODAY. AS IT DOES...SURFACE LOW PRESSURE WILL DEEPEN AS IT
MOVE NE FROM THE SOUTHERN PLAINS TO THE UPPER MISSISSIPPI RIVER
VALLEY. OUR AREA WILL BE MAINLY WARM SECTORED TODAY WITH A MIX OF
DIURNAL CUMULUS AND HIGH LEVEL CLOUDS. THERE IS STILL A SMALL
CHANCE OF A POP UP SHOWER OR STORM IN THE WARM SECTOR...BUT THIS
IS NOT HIGH ENOUGH TO MENTION IN THE TAFS. AS THE SURFACE LOW
DEEPENS AND DAYTIME MIXING KICKS IN...SOUTHERLY WINDS WILL
INCREASE AND WILL BE GUSTY BETWEEN 30 AND 35 KNOTS.
FOR TONIGHT...DEEPENING LOW PRESSURE WILL MOVE FROM THE UPPER
MISSISSIPPI RIVER VALLEY TO THE U.P. OF MICHIGAN. A DYNAMIC COLD
FRONT IS FORECAST TO PUSH EAST INTO THE REGION BETWEEN 06Z AND
12Z. AS IT DOES...A LINE OF SHOWERS AND EMBEDDED THUNDERSTORMS ARE
EXPECTED ALONG THE COLD FRONT...FOLLOWED BY A PERIOD OF MODERATE
TO LOCALLY HEAVY RAIN SHOWERS. THIS WILL RESULT IN CONDITIONS
DROPPING INTO THE MVFR CATEGORY ALONG WITH SOME IFR VISIBILITIES
IN THE HEAVIER RAIN. ALSO...WINDS WILL CONTINUE GUSTY AND SHIFT TO
THE WEST WITH FROPA. WINDS WILL BE LOCALLY HIGHER IN AND NEAR
THUNDERSTORMS. ATTM...IT APPEARS INSTABILITY WILL BE WEAKENING AS
THE FRONT PUSHES TOWARD THE KCMH/KLCK TAF SITES TOWARD 12Z SO NOT
MUCH THUNDER MAY BE LEFT BY THE TIME IT REACHES THESE TERMINALS.
OUTLOOK...MVFR CONDITIONS WITH LOCAL IFR VISIBILITIES EXPECTED IN
SHOWERS FRIDAY MORNING. WEST WINDS GUSTING TO 30 KT EXPECTED
FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BINAU
NEAR TERM...NOVAK
SHORT TERM...BINAU
LONG TERM...FRANKS
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
932 PM EDT WED APR 17 2013
.SYNOPSIS...
A POTENT SPRING STORM SYSTEM WILL EJECT NORTHEAST THROUGH THE MID
MISSISSIPPI VALLEY TONIGHT THROUGH FRIDAY...BRINGING A WILD SWING
IN TEMPERATURE AND THE THREAT OF STRONG TO SEVERE THUNDERSTORMS.
VERY WARM CONDITIONS ON THURSDAY WITH GUSTY SOUTH WINDS WILL BE
FOLLOWED BY EVEN GUSTIER NORTHWEST WINDS AND TEMPERATURES SOME 30
DEGREES LOWER THAN THAN ON THURSDAY. IN THE WAKE OF THIS
SYSTEM...COOL CANADIAN HIGH PRESSURE WILL SETTLE INTO THE OHIO
VALLEY FOR THE WEEKEND WITH THE THREAT OF MORNING FROST AND SOME
DRY WEATHER.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WARM FRONTAL BOUNDARY WILL CONTINUE TO LIFT NORTH THROUGH THE
OVERNIGHT HOURS. MOST LOCATIONS WILL REMAIN DRY THROUGH THE
OVERNIGHT HOURS HOWEVER A FEW ISOLATED STORMS MAY REACH INTO NW
PORTIONS OF THE FA ACROSS EAST CENTRAL INDIANA AND WEST CENTRAL
OHIO. WITH THE FRONT LIFTING NORTH WENT ON THE WARMER SIDE OF
GUIDANCE OR WARMER THAN GUIDANCE WITH LOW TEMPERATURES OVERNIGHT.
WINDS WILL STAY UP SOME THROUGH THE OVERNIGHT HOURS WITH A FEW
WIND GUSTS POSSIBLE AS WELL HOWEVER THE HIGHER WIND GUSTS WILL
HOLD OFF UNTIL AFTER SUNRISE ACROSS THE FA.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
FOUND MODEL AGREEMENT TO BE VERY STRONG THROUGH THIS PERIOD AND
GOING FORECAST HAD LARGELY CAPTURED THE ENTIRE FCST SCENARIO
EXTREMELY WELL...THUS CHANGES WERE REALLY FOCUSED ON DETAILS OF
WINDS/TIMING OF STORMS...AND TIGHTENING UP GRADIENTS AHEAD/BEHIND
THE EXPECTED COLD FRONT TOMORROW NIGHT.
AFTERNOON GOES WATER VAPOR IMAGERY AND RAP ANALYSIS INDICATED A
VERY DYNAMIC AND COLD LONGWAVE TROUGH /-30C AT 500MB NEAR SLC AT
12Z/ OVER THE INTERMOUNTAIN WEST WITH SEVERAL IMPRESSIVE
CONVECTIVE COMPLEXES DOWNSTREAM NEAR THE ATTENDANT FRONTAL
SYSTEMS OVER THE MID MS VALLEY. HEIGHTS HAVE BEEN RISING OVER THE
OHIO VALLEY MUCH OF THE DAY BUT THAT PROCESS WILL TURN AROUND AS A
STRONG SHORTWAVE TROUGH/UPPER JET DIGS THROUGH THE LONGWAVE TROUGH
AND EJECTS INTO THE CENTRAL PLAINS...LOWERING HEIGHTS DOWNSTREAM
OVER THE OHIO VALLEY AND ALLOWING A STRONG COLD FRONT AND LOW
PRESSURE TO FURTHER ORGANIZE AND PUSH EAST TOWARD THE AREA.
POOL OF VERY WARM /+15C AT H85/ AIR JUST TO OUR SOUTHWEST WILL
LIFT NORTHWARD AS WARM MENTIONED ABOVE CONTINUES NORTH AND DEEPER
SLY FLOW IS ATTAINED. AS DYNAMICS REALLY BEGIN TO INCREASE ON
THURSDAY MORNING...LOW LEVEL WIND FIELD AND FALLING PRESSURES TO
THE WEST WILL INDUCE A POTENT WARM ADVECTION REGIME...WITH
EFFICIENT MIXING UNDER PARTLY CLOUDY SKIES. NAM/GFS SFC PRESSURE
GRADIENT MAGNITUDES AND SOUNDING ANALYSIS VALID THURS AFTN
SUGGESTS A WINDY DAY...SUSTAINED 20 TO 30 MPH WITH GUSTS TO 40
MPH...ESPECIALLY WEST OF I-71 FROM 10 AM THROUGH THE AFTN. A
LITTLE CONCERNED FOR WIND ADVISORY CONDITIONS IN OUR FAR NORTHWEST
WHICH IS A WIND PRONE AREA AND WILL BE UNDER THE STRONGEST
INFLUENCE OF THE DEVELOPING/DEEPENING SFC-850MB CYCLONE AND
ATTENDANT LOW LEVEL JET. WILL CONTINUE TO HIGHLIGHT WIND THREAT ON
HWO. MAX TEMPS SHOULD WARM CONSIDERABLY...INTO THE 80S MOST AREAS
AND WITH A MORE SELY TRAJECTORY OVER OUR EAST...THIS IS
DOWNSLOPE/DRYING OFF THE APPALACHIAN RISE AND MAY ALLOW BETTER
DEW POINT REDUCTION/WARMING. LIKELY WILL FALL A FEW DEGREES SHORT
OF RECORDS...WHICH ARE IN THE MID/UPPER 80S.
GETS VERY INTERESTING THURSDAY AFTER ABOUT 5 PM WHEN STRONG DEEP
LAYERED ASCENT AND LOW LEVEL CONVERGENCE IN VICINITY OF FRONTAL
ZONE TO THE WEST SHOULD CONTINUE TO FOSTER DEVELOPMENT OF A VERY
LONG/STRONG SQUALL LINE. THERE/S BEEN HINTS IN THE HIGHER RES
CONVECTION ALLOWING DATA THAT A FEW DISCRETE CELLS MAY FORM IN THE
WARM SECTOR OVER OUR FAR WEST LATE AFTN/EARLY EVENING AND THAT
WOULD BE PROBLEMATIC GIVEN A WEAK MLCINH FIELD /ERODED CAP/ AND
MLCAPE AROUND 1500 J/KG AMIDST VERY STRONG FLOW /SHEAR/. RIGHT NOW
AM NOT SEEING A STRONG/CONSISTENT SIGNAL THERE...SO KEEPING RAIN
CHANCES LOW THROUGH THE DAY.
AS THE EVENING WEARS ON...ADVANCING FRONTAL ZONE /OR PREFRONTAL
TROUGH/ WILL BECOME FOCUS FOR CONTINUED ADVANCEMENT AND
DEVELOPMENT OF CONVECTIVE SQUALL LINE INTO THE WFO ILN AREA
SOMETIME BETWEEN 10 PM AND 2 AM. THINK LATEST SWODY2 FROM SPC IS
REALISTIC...THAT WFO ILN WRN CWA WILL BE A TRANSITION AREA FROM A
VERY POTENT QLCS WITH SEVERE THREAT...TO A NON-LIGHTNING PRODUCING
LINE OF RAIN OR SHOWERS LATE IN THE NIGHT INTO THE EARLY MORNING HOURS ON
FRIDAY.
CLEARLY THE HIGHEST THREATS LOCALLY OF WIND ARE IN OUR FAR WEST
BEFORE CONVECTION ENTRAINS AN INCREASINGLY HOSTILE LOW LEVEL
AIRMASS /REF ABOVE COMMENT ABOUT DRYING ON SOUTH-SELY FLOW INTO ERN
AREAS/...AND SOUNDING ANALYSIS FROM A MULTITUDE OF NWP SOURCES
INDICATES ANY SURFACE BASED/NEAR SURFACE BASED INSTBY WILL BE
MINIMAL AT BEST /100 J/KG/ WEST OF I-75. PRIOR NOCTURNAL QLCS
EVENTS HOWEVER SUGGEST MLCAPE/MUCAPE IN THESE STRONGLY FORCED
EVENTS IS OVERRATED TO A DEGREE...AND GIVEN THE EXPECTED 0-1KM
SHEAR TOWARD 50KTS...THE SHAPE/ORIENTATION OF THE LOWEST 1KM TEMP
TRACE IS VERY IMPORTANT FOR QLCS COUPLETS AND/OR DAMAGING WIND
TRANSPORT TO THE SURFACE. FCST SOUNDINGS ARE HARD TO BUY INTO
GIVEN FICKLE NATURE OF BOUNDARY LAYER RESOLUTION IN NWP...BUT
ISOTHERMAL TO WEAKLY NEGATIVE LAPSE RATES INDEED SUGGESTS WE MAY
VERY WELL HAVE A THREAT FOR DAMAGING GUSTS ESP IN THE FIRST COUPLE
OF HOURS OF THE EVENT WEST OF I-75. WITH TIME...BUOYANCY REALLY
TANKS AND EXPECT THIS CONVECTIVE SYSTEM TO STRUGGLE TO OR NOT
PRODUCE LIGHTNING OVER THE ERN 1/2 OF THE FORECAST AREA LATE IN
THE NIGHT AND FRIDAY MORNING.
ALSO...WHILE WINDS MAY DECREASE EARLY IN THE EVENING...ISALLOBARIC
COMPONENT IMMEDIATELY IN ADVANCE OF THE VERY SHARP/STRONG FRONAL
ZONE WILL PROBABLY ALLOW FOR A BRIEF/RAPID INCREASE IN SUSTAINED
AND GUSTS IMMEDIATELY AHEAD OF THE SQUALL LINE.
FOR FLOOD CONCERN...SYSTEM WILL BE PROGRESSIVE AND HAVE HIGH
CONFIDENCE IN RAIN AMOUNTS REMAINING LESS THAN AN INCH IN MOST
AREAS. HEAVIEST WEST...LIGHTEST EAST. FEEL ANY FLOODING ISSUES
WOULD BE BRIEF/NUISANCE AND TIED TO AREAS OF VERY MOIST SOILS FROM
MERCER INTO HARDIN/DELAWARE COUNTIES.
FRIDAY TO BE POLAR OPPOSITE OF THURSDAY...A 30 DEGREE TEMP CHANGE
/PERHAPS MORE IN THE WEST/ FROM DAYTIME MAX TO DAYTIME MAX...WITH
MORE GUSTY WINDS AND A RAPID END TO THE RAIN WITH DRY SLOT. THINK
WIND ADVISORY MAY BECOME LIKELY IN NORTH/WEST AT SOME POINT AS SFC
CYCLONE REACHES LOWEST PRESSURES /SUB-990MB/ OVER LAKE SUPERIOR. A
VERY CHILLY/MISERABLE DAY IN COMPARISON TO THURSDAY.
ENOUGH WEAKENING IN THE MSLP GRADIENT FRIDAY NIGHT AND POTENTIAL
CLEARING TO WARRANT INSERT OF PATCHY FROST...THOUGH FOLLOWING
NIGHT LOOKS EVEN BETTER FOR FROST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A STRONG AREA OF HIGH PRESSURE WILL BUILD IN THE MID SECTION OF THE
COUNTRY ON SATURDAY AND NOSE INTO THE GREAT LAKES AND OHIO VALLEY
REGION BY EVENING. SOUTHEAST FLOW WILL THEN GRADUALLY TURN SOUTH
AHEAD OF THE NEXT COLD FRONT EXPECTED TO MOVE THROUGH LATE IN THE
FORECAST PERIOD.
MODELS ARE IN A WIDE RANGE FOR TIMING FOR THE TUESDAY/WEDNESDAY
SYSTEM. THE PREVIOUS FORECAST APPEARS TO HAVE THE BEST INITIAL
CONDITIONS BUT SOME NEIGHBORING OFFICES APPEAR HIGHER THAN I AM
WILLING TO GO WITH RAIN CHANCES OVERNIGHT TUESDAY. GIVEN THE LATEST
EUROPEAN WHICH SPINS THE SYSTEM UP IN THE MIDWEST ON TUESDAY...IT
HAS A MUCH SLOWER AND MORE DEVELOPED SYSTEM THAN THE GFS WHICH IS
INDICATING AN OPEN WAVE YET STRONG COLD FRONTAL PASSAGE EARLY
WEDNESDAY. WPC HAS THIS FRONT ON THE OTHER SIDE OF THE APPALACHIANS
AT THIS TIME WHICH APPEARS INCONSISTENT WITH THE REST OF THE
GUIDANCE I SEE.
UNTIL THE RAIN HITS WITH THE NEXT SYSTEM DAYS 6/7...TEMPERATURES
WILL BE ON THE INCREASE AND START FROM A COOLER 50S ON SATURDAY WITH
OVERNIGHT LOWS LIKELY NEEDING FROST HEADLINES. BY THIS TIME NEXT
WEEK AHEAD OF THE COLD FRONT...70S WILL BE FOUND AGAIN WITH
OVERNIGHT LOWS IN THE 50S. HAVE GONE WARMER THAN GUIDANCE AHEAD OF
THE NEXT SYSTEM BUT FEEL THAT THE FORECAST WILL CONTINUE TO BE
ADJUSTED UPWARD A LITTLE BIT EACH DAY.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
A WARM FRONT SITUATED ACROSS THE TAF SITES WILL CONTINUE TO PUSH NORTH
TONIGHT. WINDS WILL GRADUALLY BECOME MORE SOUTHERLY ACROSS THE TAF
SITES. GUIDANCE IS SUGGESTING SOME MVFR FOG AT THE TAF SITES
OVERNIGHT HOWEVER BELIEVE WITH WINDS STAYING UP THROUGH THE NIGHT
THAT FOG WILL PROBABLY NOT BE AN ISSUE. WINDS WILL REALLY RAMP UP
FOR THE DAY ON THURSDAY WITH WIND GUSTS EXCEEDING 30 KNOTS AT
TIMES FOR THE LATE MORNING AND THROUGH THE AFTERNOON HOURS.
ALTHOUGH A FEW SPOTTY SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
DURING THE DAY ON THURSDAY COVERAGE WILL BE VERY LIMITED AND
THEREFORE LEFT OUT OF THE TAFS AT THIS TIME.
OUTLOOK...GUSTY SOUTHERLY WINDS WILL CONTINUE THROUGH THURSDAY EVENING.
A BRIEF PERIOD OF MVFR CEILINGS AND VISIBILITIES ARE POSSIBLE AS
SHOWERS AND THUNDERSTORMS MOVE THROUGH LATE THURSDAY NIGHT AND
EARLY FRIDAY MORNING. WEST WINDS GUSTING TO 30 KT LIKELY FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BINAU
NEAR TERM...NOVAK
SHORT TERM...BINAU
LONG TERM...FRANKS
AVIATION...NOVAK
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1047 PM MDT WED APR 17 2013
.UPDATE...
ISSUED AT 951 PM MDT WED APR 17 2013
KUDX RADAR INDICATES PERSISTENT BAND OF -SN FROM KEFC TO KIEN...IN
AN AREA OF CYCLONIC FLOW AND STEEP LOW LEVEL LAPSE RATES. GIVEN
00Z KUNR SOUNDING...EXPECT ACTIVITY TO PERSIST LONGER INTO THE
NIGHT...SO WILL EXPAND PREVIOUSLY HIGHER POPS AND EXTEND THEM IN
TIME. SNOW CONTINUES TO EXPAND IN NE HEADING FOR SOUTH CENTRAL
SD...SO FORECAST THERE STILL LOOK REASONABLE.
UPDATE ISSUED AT 502 PM MDT WED APR 17 2013
LATEST WATER VAPOUR LOOP AND 21Z RAP GUIDANCE SHOW NEXT WAVE OVER
NM...HEADING SWIFTLY TO THE NORTHEAST ON NOSE OF 130KT JET. LIFT
ON NOSE OF THIS JET STREAK AND EXITING JET STREAK OVER THE UPPER
MIDWEST WILL COMBINE TO BRING INCREASING AREAS OF -SN OVER
NE PER KLNX RADAR...WHICH WILL HEAD INTO SOUTH CENTRAL SD TONIGHT.
EXPECT MAIN ACCUMULATING SNOWS TO BE OVER THESE AREAS OVERNIGHT.
FURTHER WEST -SN WILL LINGER...BUT ACCUMULATIONS WILL BE LIGHT.
WILL THUS SHAVE OFF ALL HEADLINES SAVE FOR SOUTH CENTRAL SD WHERE
SEVERAL MORE INCHES OF SNOW ARE EXPECTED OVERNIGHT.
&&
.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 238 PM MDT WED APR 17 2013
CURRENT SURFACE ANALYSIS PLACES LOW OVER NORTHERN NEW MEXICO WITH
HIGH SETTLING INTO THE NORTHERN ROCKIES. UPPER LEVEL ANALYSIS
PLACES DEEP TROF OVER THE WRN INTO THE CTRL CONUS WITH AXIS
STRETCHING FROM ERN SASKATCHEWAN SOUTHWARD TOWARDS THE FOUR
CORNERS REGION...WITH BASE CLOSING OFF NEAR WRN COLORADO. VARIETY
OF WAVES CONTINUE TO PUSH UP ALONG THE FRONT OF THE WAVE. MAIN
AREA OF SNOW OVER PTNS OF SW INTO S CTRL SD ORIENTATED ALONG AXIS
OF INCREASING 700 MB FRONTOGENESIS...WHILE OTHER SMALLER BANDS
CONTINUE OVER THE CWA.
FOR TONIGHT...UPPER TROF CONTINUES ITS SLOW PUSH TO THE EAST WITH
SNOW SLOWLY TAPERING FROM WEST TO EAST THROUGH THE OVERNIGHT OVER
NERN WYO INTO WRN SD. OVER S CTRL SD...PRIMARY BAND OF SNOW SHIFTS
OVER THE AREA THIS EVENING. LATE TONIGHT PRIMARY WAVE WRAPPING
AROUND CLOSED LOW EJECTING INTO THE PLAINS WILL PASS MAINLY TO THE
EAST...THOUGH ENOUGH LIFT WITH THIS SHOULD KEEP SNOWFALL GOING
INTO THE MORNING HOURS.
ON THURSDAY...SOME SNOW WILL LINGER INTO THE MORNING HOURS OVER S
CTRL SD BEFORE SLOWLY ENDING INTO THE AFTERNOON AS UPPER LOW
SLOWLY WORKS ITS WAY TO THE EAST. OVER REMAINDER OF THE CWA...DRY
CONDITIONS ARE EXPECTED AS RIDGING QUICKLY BUILDS IN. SFC LOW
EJECTS THRU THE MIDWEST AND DEEPENS BRINGING INCREASING NRNLY
WINDS TO THE ERN CWA...WHICH MAY LEAD TO SOME BLOWING SNOW.
&&
.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 238 PM MDT WED APR 17 2013
MOSTLY DRY CONDITIONS ARE EXPECTED FRIDAY AS A SHORT WAVE RIDGE
CROSSES THE NORTHERN PLAINS. AN UPPER TROF WILL SET UP ACROSS THE
NORTHERN PLAINS FOR THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL
BRING PERIODIC CHANCES FOR RAIN/SNOW ALONG WITH TEMPERATURES
REMAINING BELOW AVERAGE. AN UPPER LEVEL RIDGE WILL START TO MOVE
INTO THE NORTHERN PLAINS AROUND MIDWEEK...BRINGING DRY CONDITIONS
AND MORE SEASONABLE TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1045 PM MDT WED APR 17 2013
WIDESPREAD IFR CONDITIONS OVER SD WILL SLOWLY MOVE EAST
TONIGHT...LEADING TO IMPROVING CONDITIONS FROM WEST TO EAST ON
THURSDAY AS A STORM SYSTEM EXITS THE REGION. LEFTOVER MVFR
CIGS/LOCAL IFR CIGS OVER NORTHEAST WY WILL SHIFT EAST TONIGHT
LEADING TO MAINLY VFR CONDITIONS THURSDAY.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM MDT THURSDAY FOR SDZ043-044.
WINTER WEATHER ADVISORY UNTIL NOON CDT THURSDAY FOR SDZ046-047-
049.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...77
LONG TERM...15
AVIATION...HELGESON
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
955 PM MDT WED APR 17 2013
.UPDATE...
ISSUED AT 951 PM MDT WED APR 17 2013
KUDX RADAR INDICATES PERSISTENT BAND OF -SN FROM KEFC TO KIEN...IN
AN AREA OF CYCLONIC FLOW AND STEEP LOW LEVEL LAPSE RATES. GIVEN
00Z KUNR SOUNDING...EXPECT ACTIVITY TO PERSIST LONGER INTO THE
NIGHT...SO WILL EXPAND PREVIOUSLY HIGHER POPS AND EXTEND THEM IN
TIME. SNOW CONTINUES TO EXPAND IN NE HEADING FOR SOUTH CENTRAL
SD...SO FORECAST THERE STILL LOOK REASONABLE.
UPDATE ISSUED AT 502 PM MDT WED APR 17 2013
LATEST WATER VAPOUR LOOP AND 21Z RAP GUIDANCE SHOW NEXT WAVE OVER
NM...HEADING SWIFTLY TO THE NORTHEAST ON NOSE OF 130KT JET. LIFT
ON NOSE OF THIS JET STREAK AND EXITING JET STREAK OVER THE UPPER
MIDWEST WILL COMBINE TO BRING INCREASING AREAS OF -SN OVER
NE PER KLNX RADAR...WHICH WILL HEAD INTO SOUTH CENTRAL SD TONIGHT.
EXPECT MAIN ACCUMULATING SNOWS TO BE OVER THESE AREAS OVERNIGHT.
FURTHER WEST -SN WILL LINGER...BUT ACCUMULATIONS WILL BE LIGHT.
WILL THUS SHAVE OFF ALL HEADLINES SAVE FOR SOUTH CENTRAL SD WHERE
SEVERAL MORE INCHES OF SNOW ARE EXPECTED OVERNIGHT.
&&
.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 238 PM MDT WED APR 17 2013
CURRENT SURFACE ANALYSIS PLACES LOW OVER NORTHERN NEW MEXICO WITH
HIGH SETTLING INTO THE NORTHERN ROCKIES. UPPER LEVEL ANALYSIS
PLACES DEEP TROF OVER THE WRN INTO THE CTRL CONUS WITH AXIS
STRETCHING FROM ERN SASKATCHEWAN SOUTHWARD TOWARDS THE FOUR
CORNERS REGION...WITH BASE CLOSING OFF NEAR WRN COLORADO. VARIETY
OF WAVES CONTINUE TO PUSH UP ALONG THE FRONT OF THE WAVE. MAIN
AREA OF SNOW OVER PTNS OF SW INTO S CTRL SD ORIENTATED ALONG AXIS
OF INCREASING 700 MB FRONTOGENESIS...WHILE OTHER SMALLER BANDS
CONTINUE OVER THE CWA.
FOR TONIGHT...UPPER TROF CONTINUES ITS SLOW PUSH TO THE EAST WITH
SNOW SLOWLY TAPERING FROM WEST TO EAST THROUGH THE OVERNIGHT OVER
NERN WYO INTO WRN SD. OVER S CTRL SD...PRIMARY BAND OF SNOW SHIFTS
OVER THE AREA THIS EVENING. LATE TONIGHT PRIMARY WAVE WRAPPING
AROUND CLOSED LOW EJECTING INTO THE PLAINS WILL PASS MAINLY TO THE
EAST...THOUGH ENOUGH LIFT WITH THIS SHOULD KEEP SNOWFALL GOING
INTO THE MORNING HOURS.
ON THURSDAY...SOME SNOW WILL LINGER INTO THE MORNING HOURS OVER S
CTRL SD BEFORE SLOWLY ENDING INTO THE AFTERNOON AS UPPER LOW
SLOWLY WORKS ITS WAY TO THE EAST. OVER REMAINDER OF THE CWA...DRY
CONDITIONS ARE EXPECTED AS RIDGING QUICKLY BUILDS IN. SFC LOW
EJECTS THRU THE MIDWEST AND DEEPENS BRINGING INCREASING NRNLY
WINDS TO THE ERN CWA...WHICH MAY LEAD TO SOME BLOWING SNOW.
&&
.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 238 PM MDT WED APR 17 2013
MOSTLY DRY CONDITIONS ARE EXPECTED FRIDAY AS A SHORT WAVE RIDGE
CROSSES THE NORTHERN PLAINS. AN UPPER TROF WILL SET UP ACROSS THE
NORTHERN PLAINS FOR THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL
BRING PERIODIC CHANCES FOR RAIN/SNOW ALONG WITH TEMPERATURES
REMAINING BELOW AVERAGE. AN UPPER LEVEL RIDGE WILL START TO MOVE
INTO THE NORTHERN PLAINS AROUND MIDWEEK...BRINGING DRY CONDITIONS
AND MORE SEASONABLE TEMPERATURES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 502 PM MDT WED APR 17 2013
WIDESPREAD IFR/MVFR CONDITIONS DUE TO LOW CLOUDS/-SN EXPECTED TONIGHT
INTO EARLY THURSDAY MORNING ACROSS MUCH WESTERN SD. CONDITIONS
WILL BEGIN TO SLOWLY IMPROVE ACROSS NORTHEAST WYOMING LATER THIS
EVENING AND OVERNIGHT AS SNOW TAPERS OFF AND CEILINGS RISE TO MVFR
LEVELS. CONDITIONS WILL THEN IMPROVE THURSDAY AS STORM SYSTEM
MOVES TO THE EAST.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM MDT THURSDAY FOR SDZ043-044.
WINTER WEATHER ADVISORY UNTIL NOON CDT THURSDAY FOR SDZ046-047-
049.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...77
LONG TERM...15
AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
400 AM CDT THU APR 18 2013
...MODERATE RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO
TONIGHT...
.DISCUSSION...
FEW OVERALL CHANGES TO THE FORECAST OVER THE NEXT WEEK...WITH
MAINLY SLIGHT ADJUSTMENTS TO TEMPS AND TIMING OF PRECIP. A LARGE
H5 TROUGH OVER THE PLAINS STATES WILL SHIFT INTO THE MISSISSIPPI
VALLEY TODAY THEN ACROSS THE TENNESSEE VALLEY TONIGHT...WITH AN
ASSOCIATED STRONG COLD FRONT SWEEPING THROUGH THE MID STATE
TONIGHT. BEFORE THE FRONT ARRIVES...ANOTHER SUMMER-LIKE DAY IS ON
TAP WITH TEMPERATURES STARTING OUT IN THE 60S TO AROUND 70 THIS
MORNING THEN WARMING UP INTO THE LOW TO MID 80S AREAWIDE THIS
AFTERNOON. AS A SUB-1000MB SURFACE LOW TAKES SHAPE ACROSS THE
MIDWEST...925MB WINDS WILL INCREASE ACROSS OUR REGION INTO THE
40-50KT RANGE TODAY LEADING TO GUSTY SOUTH WINDS AT THE SURFACE.
ANTICIPATING SOUTH WINDS IN THE 15 TO 30 MPH RANGE DEVELOPING LATER
THIS MORNING...THEN CONTINUING INTO THE AFTERNOON HOURS BEFORE
SUBSIDING SOMEWHAT EARLY IN THE EVENING. OCCASIONAL GUSTS TO NEAR
40 MPH APPEAR LIKELY AS WELL BASED ON BUFKIT SOUNDINGS. SOUTH
WINDS WILL INCREASE AGAIN LATER IN THE EVENING AS A SHARP PRESSURE
GRADIENT MOVES ACROSS THE MID STATE AHEAD OF THE COLD FRONT. TO
SIMPLIFY MATTERS...HAVE ISSUED A WIND ADVISORY FOR ALL ZONES
BEGINNING LATER THIS MORNING AND CONTINUING THROUGH THE EARLY
MORNING HOURS ON FRIDAY.
SPC HAS PLACED AREAS ALONG AND WEST OF THE I-65 CORRIDOR IN A
MODERATE RISK FOR SEVERE STORMS THURSDAY EVENING WITH A SLIGHT
RISK TO THE EAST THURSDAY NIGHT. 00Z GFS/NAM/ECMWF AND LATEST
HIGH RESOLUTION 4.0 KM WRF...NSSL WRF...AND HRRR ALL INDICATE A
STRONG TO SEVERE QLCS WILL FORM LATER TODAY ALONG THE
FRONT...REACHING THE TENNESSEE RIVER BY MID EVENING...I-65
CORRIDOR AROUND MIDNIGHT...AND EXIT EAST OF THE CWA NEAR/AFTER
SUNRISE FRIDAY MORNING. MODELS CONTINUE TO DEPICT GENERALLY WEAK
INSTABILITY AROUND 500 J/KG AHEAD OF THE LINE...BUT SOME GUIDANCE
INDICATES A SURGE OF MID/UPPER 60S DEWPOINTS COMING NORTHWARD
AHEAD OF THE QLCS WHICH COULD BUMP UP CAPE VALUES TO NEAR/OVER
1000 J/KG ACROSS WESTERN ZONES. REGARDLESS...IMPRESSIVE 0-3KM SRH
STRENGTHENING INTO THE 500-800 M2/S2 RANGE AND VERY LONG CURVED
HODOGRAPHS SUGGESTS A SIGNIFICANT DAMAGING WIND THREAT WITH THE
LINE OF STORMS ALONG WITH SOME QLCS TORNADOES. HIGHEST RISK OF
DAMAGING WINDS/TORNADOES IS EXPECTED TO BE ALONG/WEST OF I-65 IN
THE 02-06Z TIMEFRAME ACROSS THE MODERATE RISK AREA...AS STORMS
WILL ENCOUNTER INCREASINGLY LESS INSTABILITY AND WEAKENING SHEAR
OFF TO THE EAST.
STRATIFORM RAIN AND A FEW THUNDERSTORMS WILL CONTINUE MUCH OF THE
NIGHT BEHIND THE QLCS WITH RAINFALL COMING TO AN END FROM WEST TO
EAST FRIDAY MORNING. MUCH COOLER TEMPERATURES ARE ANTICIPATED
FRIDAY AND SATURDAY WITH LOWS FALLING INTO THE MID TO UPPER 30S
SATURDAY MORNING. WITH SURFACE RIDGE SETTLING OVER THE MID
STATE...LIGHT TO CALM WINDS...AND DEWPOINTS FALLING INTO THE 20S
AND 30S...PATCHY FROST APPEARS POSSIBLE FOR MUCH OF THE FORECAST
AREA AND HAVE ADDED MENTION TO ZONES. AREA WILL BEGIN TO WARMUP
FROM SUNDAY INTO EARLY NEXT WEEK AS SOUTHERLY FLOW BEGINS ANEW.
FEW CHANGES WERE MADE IN THE EXTENDED FORECAST WITH NEXT CHANCE
FOR RAIN AROUND TUESDAY/WEDNESDAY OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 85 53 58 37 / 10 100 20 10
CLARKSVILLE 85 49 57 34 / 10 100 10 10
CROSSVILLE 80 58 61 34 / 10 100 60 10
COLUMBIA 85 54 60 37 / 10 100 20 10
LAWRENCEBURG 85 54 60 36 / 10 100 20 10
WAVERLY 84 50 57 35 / 10 100 10 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 10 AM THIS MORNING TO 1 AM CDT FRIDAY FOR
TNZ005>011-022>034-056>066-075-077>080-093>095.
&&
$$
SHAMBURGER
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1143 PM CDT WED APR 17 2013
.UPDATE...
ISSUED AT 904 PM CDT WED APR 17 2013
THE NEXT BAND OF RAIN IS CURRENTLY MOVING THROUGH THE REGION AND
SHOULD LAST THROUGH THE NEXT 2 TO 4 HOURS PROVIDING ABOUT 0.20 TO
0.40 OF AN INCH OF RAIN. WITH THE MAIN AXIS OF LOW LEVEL MOISTURE
TRANSPORT AND HIGHER INSTABILITY STAYING TO THE SOUTHEAST INTO
TOMORROW...HAVE DECIDED TO DROP THE FLOOD WATCH FOR THE
NORTHWESTERN HALF OF THE FORECAST AREA. WILL HAVE AN UPDATE COMING
OUT SHORTLY WITH THIS CANCELLATION. OTHERWISE...LIGHTNING HAS
REALLY DWINDLED OVER THE PAST FEW HOURS AS THIS RAIN HAS RUN INTO
THE REGION THAT HAS LITTLE TO NO INSTABILITY. THE LAST FEW RUNS OF
THE RAP HAVE KEPT THE HIGHER 0-3KM MUCAPE OFF TO THE EAST OF THE
FORECAST AREA AS WELL...SO AM NOT ANTICIPATING MUCH IN THE WAY OF
HAIL TO OCCUR. DUAL POL RADAR ANALYSIS SHOWS SOME BRIGHT BANDING
AS WELL AROUND 6-7KFT WITH ALL LIQUID PRECIPITATION LIKELY MAKING
IT DOWN TO THE GROUND.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 305 PM CDT WED APR 17 2013
MAIN FORECAST CONCERNS ARE ON HEAVY RAINFALL TONIGHT THROUGH
THURSDAY AND LARGE HAIL POTENTIAL THIS EVENING INTO THE OVERNIGHT
HOURS. FOCUS THEN TURNS TO PERSISTENT RAINFALL THROUGH THE DAY ON
THURSDAY...WITH PRECIPITATION SWITCHING OVER TO SNOW THURSDAY
NIGHT.
LATEST WATER VAPOR IMAGERY SHOWED A POTENT TROUGH DIGGING INTO THE
FOUR CORNERS REGION WITH SOUTHWEST FLOW ALOFT SETTING UP OVER THE
UPPER MISSISSIPPI RIVER VALLEY. A MOIST...UNSTABLE AIRMASS WAS
ADVECTING NORTHWARD OUT OF THE MIDDLE MISSISSIPPI RIVER VALLEY AND
INTERACTING WITH SHORTWAVE ENERGY EMBEDDED IN THE SOUTHWEST FLOW.
SHOWERS AND THUNDERSTORMS HAVE BEEN ONGOING ACROSS ACROSS MUCH OF
IOWA THROUGH NORTHERN ILLINOIS AND FAR SOUTHWEST WISCONSIN.
THE SURGE OF MOIST UNSTABLE AIR CONTINUES ITS NORTHWARD PROGRESSION
TONIGHT ON THE NOSE OF A STRONG LOW LEVEL JET. PRECIPITABLE WATER
VALUES CLIMB INTO THE 1 TO 1.5 INCH RANGE...WHICH IS 160 TO 230
PERCENT OF NORMAL. ALSO...MUCAPE VALUES INCREASE TO AROUND 1500J/KG
ACROSS EXTREME NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN THIS
EVENING INTO THE OVERNIGHT HOURS...WHERE A FEW STORMS COULD PRODUCE
LARGE HAIL. WARM CLOUD DEPTHS ALSO INCREASE TONIGHT TO AROUND 3000 M
WHICH ALSO IS CONDUCIVE TO HEAVY RAIN POTENTIAL. OVERALL SHEAR IS
RATHER WEAK TONIGHT WITH 1 TO 7 KM BULK SHEAR VALUES OF ONLY 15 TO
25 KTS. A STRONG BAROCLINIC ZONE SETS UP ACROSS THE AREA WITH THE
WARMEST AIR LOCATED AROUND 925 MB. PLENTY OF SUPPORT FOR SHOWERS AND
THUNDERSTORMS TONIGHT ACROSS THE FORECAST AREA WITH THE BAROCLINIC
ZONE COLLOCATED WITH THE RIGHT ENTRANCE REGION OF A 250 MB JET.
FORECAST MODELS HAVE BEEN TRENDING SLIGHTLY MORE SOUTHEAST WITH THE
HEAVIER RAINFALL AMOUNTS KEEPING THE HIGHEST TOTALS GENERALLY
SOUTHEAST OF AN OELWEIN IOWA TO MAUSTON WISCONSIN LINE. 2 TO 3
INCHES OF RAINFALL ARE POSSIBLE OVER THESE AREAS WITH 1 TO 2 INCHES
POSSIBLE FOR LOCATIONS TO THE NORTH AND WEST. HOWEVER...THIS WILL
GREATLY DEPEND UPON WHICH AREAS THE THUNDERSTORMS TRAIN OVER. FLASH
FLOODING IS POSSIBLE TONIGHT IF RAINFALL RATES BECOME HIGH ENOUGH.
THE HIGHEST CHANCES FOR FLASH FLOODING APPEAR TO BE OVER EXTREME
SOUTHWEST WISCONSIN...MAINLY GRANT...CRAWFORD...AND RICHLAND
COUNTIES. WILL HAVE TO KEEP A VERY CLOSE EYE ON THIS SITUATION
DURING THE OVERNIGHT HOURS. SHOWERS AND ISOLATED THUNDERSTORMS WILL
BE ONGOING INTO THURSDAY MORNING THEN THE HEAVIER RAINFALL WILL
FINALLY SHIFT SOUTHEAST OF THE AREA BY THURSDAY AFTERNOON AS THE
TROUGH LIFTS NORTH INTO EASTERN SOUTH DAKOTA/NEBRASKA AND CLOSES
INTO AN UPPER LOW. COLDER AIR FILTERS INTO THE REGION FROM THE WEST
ON THURSDAY POTENTIALLY BRING SOME SNOW TO THE FORECAST AREA. A DRY
SLOT PUNCHES INTO THE AREA FROM THE SOUTHWEST ON THURSDAY WITH THE
FORECAST AREA LOSING DEEP SATURATION. LIGHT RAIN WILL SWITCH OVER TO
DRIZZLE AS THE DRY SLOT MOVES IN. THE UPPER LOW IS EXPECTED TO MOVE
ACROSS SOUTHWEST MINNESOTA LATE THURSDAY AFTERNOON THEN ADVANCE
NORTHEAST INTO EAST CENTRAL MINNESOTA THURSDAY EVENING. A BAND OF
SNOW WILL FALL ON THE THE NORTHERN SIDE OF THE LOW TRACK FROM
EASTERN SOUTH DAKOTA...INTO CENTRAL MINNESOTA THROUGH NORTHERN
WISCONSIN. THE BULK OF THE FORECAST AREA WILL NOT SEE ICE ALOFT SO
WHERE TEMPERATURES DROP BELOW FREEZING SOME LIGHT FREEZING DRIZZLE
OR FREEZING RAIN IS POSSIBLE...ESPECIALLY THURSDAY EVENING AS
SURFACE TEMPERATURES FALL BELOW FREEZING. ICE FINALLY MOVES IN ALOFT
THURSDAY NIGHT. ACROSS PORTIONS OF SOUTHEAST MINNESOTA THROUGH NORTH
CENTRAL WISCONSIN...PLAN ON SNOW ACCUMULATIONS OF 1 TO 3 INCHES.
NORTHEAST IOWA INTO SOUTHWEST AND CENTRAL WISCONSIN SHOULD SEE
ACCUMULATIONS OF 1/2 INCH TO AROUND AN INCH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT WED APR 17 2013
THE LOW IS EXPECTED TO GRADUALLY PROGRESS NORTHEAST INTO WESTERN
UPPER MICHIGAN EARLY FRIDAY MORNING. SNOW SHOWERS WILL CONTINUE
ACROSS MUCH OF THE AREA FRIDAY MORNING...THEN SWITCHING OVER MAINLY
TO RAIN SHOWERS FRIDAY AFTERNOON. PLAN ON BREEZY WEST/NORTHWEST
WINDS THURSDAY NIGHT THROUGH FRIDAY WITH A TIGHT PRESSURE GRADIENT
OVER THE REGION WITH SPEEDS OF 15 TO 25 MPH WITH GUSTS TO AROUND 35
MPH POSSIBLE...ESPECIALLY DURING THE DAY ON FRIDAY. HIGH
TEMPERATURES ON FRIDAY WILL RANGE FROM THE LOWER 30S OVER NORTHERN
WISCONSIN TO AROUND 40 ACROSS NORTHEAST IOWA. CHILLY NORTHWEST FLOW
CONTINUES ACROSS THE REGION FRIDAY NIGHT THROUGH SATURDAY AS HIGH
PRESSURE BUILDS IN. THERE WILL BE A BRIEF BREAK IN PRECIPITATION
CHANCES DURING THE DAY ON SATURDAY AHEAD OF ANOTHER TROUGH MOVING IN
FROM THE NORTHERN PLAINS. SKIES WILL START OUT MOSTLY SUNNY ON
SATURDAY WITH INCREASING CLOUD EXPECTED DURING THE AFTERNOON HOURS.
PLAN ON HIGHS ON SATURDAY RANGING FROM AROUND 40 OVER NORTH CENTRAL
WISCONSIN TO THE UPPER 40S ACROSS NORTHEAST IOWA. THE HIGH QUICKLY
SLIDES OFF TO THE EAST SATURDAY NIGHT. THE TROUGH LOOKS TO MOVE INTO
THE UPPER MISSISSIPPI RIVER VALLEY ON SUNDAY SPREADING SHOWERS
ACROSS THE AREA. IF THE PRECIPITATION SPREADS IN SATURDAY NIGHT...A
WINTER MIX IS POSSIBLE. ACTIVE SOUTHWEST FLOW SETS UP ONCE AGAIN
ACROSS THE REGION GOING INTO NEXT WEEK AS A TROUGH DEVELOPS OVER
THE CENTRAL CONUS. SEVERAL WAVES EJECT NORTHEAST OUT OF THE TROUGH
AND HAVE THE POTENTIAL TO BRING A FEW ROUNDS OF SHOWERS AND
THUNDERSTORMS TO THE AREA. MAJOR DIFFERENCES NOTED IN THE TIMING
OF THESE WAVES AND EXACTLY HOW THE TROUGH EVOLVES TUESDAY INTO
WEDNESDAY SO WILL HAVE TO KEEP A VERY CLOSE WATCH ON THIS
SITUATION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1143 PM CDT WED APR 17 2013
THE MAIN FOCUS THROUGH TOMORROW NIGHT IS WITH PRECIPITATION TRENDS
ALONG WITH THE LIFR TO MVFR FLIGHT CONDITIONS. THE FIRST WAVE OF
RAINFALL IS COMING TO AN END WITH A PERIOD OF DRIZZLE POSSIBLE
THROUGH THE EARLY MORNING HOURS BEFORE THE NEXT ROUND MOVES IN.
THUNDER DOES NOT LOOK LIKELY AS THIS NEXT WAVE MOVES IN...THOUGH
FLIGHT CONDITIONS WILL LIKELY REMAIN WHERE THEY ARE AT OR DROP AS
THE PRECIPITATION MOVES IN. AFTER THIS WAVE MOVES THROUGH...IT
APPEARS THAT DRIZZLE WILL LIKELY BE THE MAIN PRECIPITATION TYPE
GOING INTO THE EVENING HOURS BEFORE THE LOW LEVEL TEMPERATURES
COOL ENOUGH TO CHANGE IT OVER TO SNOW. RST WILL BE THE FIRST TO
CHANGE OVER TO SNOW BY MID EVENING WITH LSE COMING AROUND 6-8Z.
&&
.HYDROLOGY...TONIGHT THROUGH THURSDAY
ISSUED AT 305 PM CDT WED APR 17 2013
FLOOD WATCH IN EFFECT THROUGH THURSDAY NIGHT.
A VERY MOIST AIR MASS WILL MOVE INTO THE AREA TONIGHT FROM THE MIDDLE
MISSISSIPPI RIVER VALLEY...WITH PRECIPITABLE WATER VALUES IN THE
1-1.5 INCH RANGE WHICH IS 160 TO 230 PERCENT ABOVE NORMAL. THIS
MOISTURE TRANSPORT AND LIFT...COUPLED WITH UPPER LEVEL DYNAMICS
WILL TAP THIS MOISTURE TO PRODUCE 1 TO 3 INCHES OF RAINFALL
TONIGHT THROUGH THURSDAY NIGHT. THE HIGHEST AMOUNTS WILL LIKELY BE
FOCUSED ACROSS NORTHEAST IA INTO SOUTHWEST WI. ALSO...IF
THUNDERSTORMS TRAIN OVER AREAS...FLASH FLOODING IS POSSIBLE
TONIGHT INTO EARLY THURSDAY MORNING MAINLY OVER EXTREME NORTHEAST
IOWA INTO FAR SOUTHWEST WISCONSIN.
WITH MANY RIVERS RUNNING HIGH OR ALREADY IN FLOOD...THIS
RAINFALL...ALONG WITH SNOW MELT FROM THE SNOW PACK NORTH OF
WISCONSIN HIGHWAY 10 AND STILL SOME FROZEN GROUNDS...WILL HEIGHTEN
THE FLOOD THREAT. MANY RIVERS WILL GO INTO...OR BACK INTO...FLOOD.
IN ADDITION...THERE WILL BE PONDING OF WATER ON ROADWAYS ALONG WITH
STANDING WATER IN LOW LYING AND POOR DRAINAGE AREAS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FLOOD WATCH THROUGH LATE THURSDAY NIGHT FOR WIZ042>044-053>055-
061.
MN...NONE.
IA...FLOOD WATCH THROUGH LATE THURSDAY NIGHT FOR IAZ011-029-030.
&&
$$
UPDATE...HALBACH
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...HALBACH
HYDROLOGY...WETENKAMP
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
330 AM CDT THU APR 18 2013
.MESOSCALE DISCUSSION...
235 AM CDT
A CONTINUED TEXTBOOK SETUP FOR HEAVY RAIN REMAINS IN PLACE EARLY
THIS MORNING AND WILL THROUGH LATE MORNING ACROSS THE FORECAST
AREA...WITH SIGNIFICANT...EVEN RECORD RIVER FLOODING...A RESPONSE
OVER THE NEXT COUPLE DAYS. WHILE AREAL FLOODING REPORTS HAVE
BECOME A MORE FAR AND FEW BETWEEN VERY EARLY THIS MORNING...ONLY
PART OF THAT IS LIKELY DUE TO A TEMPORARY EASE IN RAINFALL RATES
AND MORE OF IT DUE TO THE FACT IT IS DARK OUTSIDE. RAINFALL
AMOUNTS ESTIMATED BY RADAR OR OBSERVED THROUGH 1 AM THURSDAY ARE
BETWEEN ONE AND A HALF TO FOUR INCHES....WITH THE HIGHEST AMOUNTS
IN NORTHWEST LIVINGSTON COUNTY...THE PANHANDLE OF LASALLE
COUNTY...AND WESTERN LEE AND OGLE COUNTIES.
THE ELEVATED STATIONARY FRONT IS PARKED DIRECTLY OVER THE CWA WITH
CONTINUOUS -70C CLOUD TOPS AND ASSOCIATED DEEP CONVECTION TRAINING
ENE. IMPRESSIVE LOW-LEVEL CONVERGENCE IS FOCUSED ALONG THIS
BOUNDARY AS JUST INFERRED BY THE VAD WIND PROFILER ANALYSIS EARLY
THIS MORNING...WITH 70 KTS OF SOUTHERLY 850MB FLOW OVER LSX AND
ILX...25 KTS AT LOT...AND NORTHERLY FLOW AT DVN AND MKX. THE
REPLENISHMENT OF MOISTURE ON THIS LOW-LEVEL JET IS EXTREME...WITH
MOISTURE TRANSPORT MAGNITUDES VERY HIGH. AMBIENT MOISTURE VALUES
ARE ALSO PRACTICALLY OFF THE CHARTS...WITH PWAT VALUES RIGHT AT
AND POSSIBLY OVER RECORD APRIL LEVELS BASED ON THE HISTORICAL RAOB
RECORDS. A TONGUE OF 4C AND HIGHER DEW POINTS AT 700MB ON LAST
EVES RAOBS AND CONTINUED TO BE ANALYZED ARE DIRECTED RIGHT INTO
THE AREA...WHICH ARE AT LEVELS SHOWN TO REFLECT WARM SEASON RAIN
PROCESSES. REFLECTIVITY SINCE MIDNIGHT HAS LOST SOME OF ITS
ORGANIZED EMBEDDED STORMS...HOWEVER THE AMOUNT OF 40+ DBZ REMAINS
HIGH ALONG WITH LIGHTNING...BOTH REFLECTIVE OF HEAVIER RAINFALL
RATES. AGAIN...CONTENT/CONCENTRATION...REPLENISHMENT...AND
FOCUS/POOLING OF HEAVY RAINFALL PARAMETERS ARE ALL IN PLACE.
LOOKING FORWARD THROUGH 10 AM...THESE PARAMETERS ALMOST ENTIRELY
REMAIN IN PLACE. WITH SIX HOUR FLOOD GUIDANCE BEING APPROACHED AND
MORE OF THE WATER TURNING INTO RUNOFF IMMEDIATELY...THIS IS LIKELY
IN ITSELF TO CAUSE FLOODING ISSUES. WHILE THE BOUNDARY HAS TRIED
TO INCH NORTHWARD AND THAT HAS BEEN SEEN SLIGHTLY IN THE RAIN
PLACEMENT...AN APPROACHING DEEP SHORT WAVE FROM WESTERN MO WILL
LIKELY CONTINUE TO BLOSSOM CONVECTION ACROSS WESTERN IL INTO THE
FORECAST AREA. SO AN UPTICK IN CONVECTION IS PROBABLE...AND THUS
EVEN SOME HEAVIER RAINFALL RATES FOR A PERIOD. THIS IS MOST
FAVORED SOUTH OF INTERSTATE 88 ON CONVECTIVE ALLOWING MODELS. HAVE
GONE WITH FLOOD WARNINGS BUT FLASH FLOODING AS THIS PASSES ACROSS
MAY BE SEEN...ESPECIALLY IN PARTS OF LA SALLE AND LIVINGSTON
COUNTIES...AS WELL AS ANY URBAN AREAS IMPACTED.
MTF
&&
.DISCUSSION...
934 PM CDT
EVENING/MESOSCALE UPDATE...
HAVE CANCELLED REMAINING CONVECTIVE WATCHES...THOUGH FLOODING WILL
CONTINUE TO BE A SIGNIFICANT ISSUE THROUGH THURSDAY AND BEYOND.
WARM FRONT EXTENDS FROM LOW PRESSURE WAVE OVER WESTERN MISSOURI...
NORTHEAST INTO CENTRAL ILLINOIS AND CENTRAL INDIANA AT 02Z. OUTFLOW
FROM PERSISTENT ELEVATED THUNDERSTORMS ACROSS IA/NORTHERN IL/IN HAS
CONTINUED TO SUPPRESS SURFACE WARM FRONT SOUTH OF THE CWA...AND WILL
LIKELY CONTINUE TO DO SO OVERNIGHT BEFORE DEEPENING SURFACE LOW
LIFTS FROM MISSOURI INTO NORTHWEST IL IN ASSOCIATION WITH SHORT WAVE
LIFTING OUT OF BASE OF UPPER TROUGH OVER THE SOUTHERN PLAINS.
UNFORTUNATELY...THIS WILL RESULT IN CONTINUED FORCED ASCENT ATOP
CONVECTIVELY ENHANCED FRONTAL ZONE TONIGHT WITHIN A BROAD REGION OF
PERSISTENT STRONG WARM/MOIST ADVECTION AHEAD OF DEEP UPPER TROUGH
OVER THE PLAINS.
ILX 00Z SOUNDING TELLS THE STORY WITH RESPECT TO THE DIMINISHED
SEVERE THREAT WITH STRONG LOW LEVEL INVERSION NORTH OF FRONT
PREVENTING NEAR SFC-BASED STORMS. RAP GUIDANCE CONTINUES TO DEPICT A
GRADIENT IN THE MUCAPE FIELD INCREASING TO 500-1000 J/KG AS YOU MOVE
FARTHER SOUTH OF I-80. WHILE EFFECTIVE BULK SHEAR IN EXCESS OF 60 KT
WILL CONTINUE TO ALLOW SOME ORGANIZATION FOR ELEVATED CONVECTION
NORTH OF WARM FRONT...THE THREAT OF SEVERE WEATHER SHOULD BE
LIMITED TO MARGINAL HAIL WITH THE BETTER ORGANIZED STORMS.
WHILE THE SEVERE THREAT INTO THE OVERNIGHT HOURS IS RATHER LOW...
FLOODING THREAT CONTINUES TO BE SIGNIFICANT INTO THURSDAY. RADAR
ESTIMATES AND OBSERVED RAINFALL REPORTS INDICATE THAT MOST AREAS
HAVE SEEN UPWARDS OF 0.75 INCHES OF RAIN...WITH MANY AREAS BETWEEN
1.5 AND 2.0 INCHES AND PARTS OF NORTH CENTRAL ILLINOIS IN EXCESS OF
2.5 INCHES. ILX 00Z RAOB DEPICTS PWAT OF 1.38 INCHES...199 PERCENT
OF NORMAL...AN INDICATION OF THE VERY MOIST AIR MASS. ADDITIONAL
RAINFALL AMOUNTS IN THE 1-2 INCH RANGE ARE VERY LIKELY THROUGH
THURSDAY...LIKELY LEADING TO EXTENSIVE FLOODING ON AREA STREAMS AND
RIVERS. AERIAL FLOOD WARNINGS REMAIN IN EFFECT INTO MIDDAY
THURSDAY...AND MANY RIVER FORECAST SITES ARE HEADED FOR MODERATE TO
MAJOR FLOODING.
RATZER
//PREV DISCUSSION...
342 PM CDT
.SHORT TERM...THROUGH FRIDAY...
HAZARDOUS WEATHER ISSUES FROM SEVERE THUNDERSTORMS TO EXCESSIVE
RAINFALL TO TORNADIC POTENTIAL WILL IMPACT THE REGION THROUGH
THURSDAY NIGHT.
FOR THE REMAINDER OF THE AFTERNOON AND INTO THIS EVENING...AT 230PM
CDT...STRONG THUNDERSTORMS EXTEND ALONG A LINE FROM NEAR
WAUKEGAN...SOUTHWEST THROUGH OTTAWA. WEST OF THIS LINE...AN
EXTENSIVE AREA OF OVERRUNNING PCPN WITH EMBEDDED THUNDER EXTENDED
BACK THROUGH ERN IOWA AND MISSOURI. MUCH OF THE ACTIVITY OVER NRN
IL HAS FORMED ALONG AN ELEVATED WARM FRONT...BUT A MORE SOLID LINE
HAS DEVELOPED IN THE WARM SECTOR. EXPECT THAT THE THUNDERSTORMS
WILL SAG SEWD THROUGH THE EVENING...BRINGING SHOWERS AND
THUNDERSTORMS INTO EAST-CENTRAL ILLINOIS AND NORTHWESTERN INDIANA.
WITH COPIOUS AMOUNTS OF MOISTURE STREAMING INTO THE REGION...THE
STORMS HAVE BEEN VERY EFFICIENT RAIN PRODUCERS...WITH 0.81 INCHES OF
RAIN MEASURED AT THE ROCKFORD AIRPORT BTWN 12-18Z THIS MORNING.
STORMS HAVE ALSO BEEN MARGINALLY SEVERE WITH NUMEROUS REPORTS OF
SMALL HAIL RECEIVED...AND A FEW REPORTS OF LARGER HAIL AS WELL.
THIS WILL BE THE CONVECTIVE MODE FOR THE REMAINDER OF THE EVENING
AND OVERNIGHT TONIGHT...WITH MODERATE TO HEAVY RAIN AND SMALL HAIL
AND OCCASIONAL STRONG WINDS GUSTS.
THE FLOODING AND SEVERE WEATHER POTENTIAL WILL RAMP UP EVEN FURTHER
TOMORROW AS THE UPPER TROUGH MOVES OUT OVER THE CENTRAL PLAINS AND A
SFC LOW DEEPENS. THE SFC LOW WILL SWING THROUGH THE SOUTH HIGH
PLAINS EARLY THIS EVENING BEFORE TURNING NEWD...RIPPLING ALONG A
QUASI-STATIONARY COLD FRONT AND WARM FRONT. BY THURSDAY
MORNING...THE LOW WILL ELONGATE FROM NWRN IL THROUGH NWRN MO...WITH
THE SFC WARM FRONT EXTENDING NEWD ACROSS CENTRAL LAKE MICHIGAN.
THIS WILL PUT THE CWA FIRMLY IN THE WARM SECTOR. WITH A WIDE OPEN
GLFMEX...DEEP LAYER MOISTURE WILL STREAM NWD INTO THE REGION...WITH
PWATS EXCEEDING 1.5 INCHES FOR AN EXTENDED PERIOD OF TIME...LEADING
TO THE POTENTIAL FOR SIGNIFICANT WIDESPREAD RIVER AND AREAL
FLOODING. SEE THE HYDROLOGY SECTION FOR FURTHER DETAILS.
THE SEVERE WEATHER MODE SHOULD FOCUS ON STRONG...DAMAGING WINDS AND
POSSIBLE TORNADOES. THE LATEST SPC DAY 2 CONVECTIVE OUTLOOK HAS
INCREASED THE AREA SOUTH OF A LINE FROM EVANSTON TO PONTIAC TO A
MODERATE RISK...WITH THE REMAINDER OF THE AREA IN A SLIGHT RISK.
INCREASING HEAT AND MOISTURE...TEMPERATURES REACHING INTO THE LOW TO
MIDDLE 70S AND DEW POINTS IN THE LOW TO MIDDLE 60S IN THE WARM
SECTOR...INSTABILITY WILL BE AMPLE. WHILE THE GENERAL CONVECTIVE
MODE WILL BE LINEAR WITH SMALL LINES AND BOWS POSSIBLE...PRODUCING
DAMAGING WINDS...THE MODEL GUIDANCE IS IN GOOD AGREEMENT ON A STRONG
LOW LEVEL JET...WITH SWLY WINDS OF 55-65KT ACROSS THE REGION. WHILE
SFC WINDS ARE GENERALLY PROGGED TO BE SOUTHERLY...THERE WILL BE
OPPORTUNITY FOR SFC WINDS TO BACK A LITTLE MORE EAST OF SOUTH AS THE
SFC LOW TRACKS THROUGH NWRN IL AND INTO SRN WI. GIVEN THE AMPLE
INSTABILITY...COMBINED WITH CLOCKWISE TURNING HODOGRAPHS...DISCRETE
SUPER CELLS MAY DEVELOP OUT IN THE WARM SECTOR AHEAD OF THE LINEAR
CONVECTION...WHICH WOULD BRING THE TORNADIC POTENTIAL TO THE
REGION.
THE POTENTIAL FOR SEVERE WEATHER AND HEAVY RAINFALL WILL CONTINUE
UNTIL THE ASSOCIATED COLD FRONT PUSHES THROUGH THE REGION...BRINGING
IN MUCH COOLER AIR. THE GUIDANCE IS IN GOOD AGREEMENT ON PUSHING
THE FRONT ACROSS THE AREA THURSDAY EVENING. AS THE SFC LOW PUSHES
OFF TO THE NORTHEAST...THE UPPER TROUGH WILL ALSO CROSS THE AREA.
WITH PLENTY OF RESIDUAL SFC MOISTURE AND COOLER AIR AND CYCLONIC
CURVATURE ALOFT...SOME LINGERING INSTABILITY SHOWERS SHOULD PERSIST
INTO FRIDAY. HIGHS ON FRIDAY SHOULD DROP BACK INTO THE MIDDLE TO
UPPER 40S.
KREIN
.LONG TERM - SATURDAY THROUGH WEDNESDAY...
SPRAWLING SURFACE HIGH PRESSURE TO BUILD INTO THE AREA SATURDAY
BEHIND DEPARTING SURFACE LOW/UPPER LEVEL TROUGH. A RETURN TO
UNSEASONABLY COOL TEMPS WITH A NEEDED BREAK IN PRECIPITATION WILL BE
SHORT LIVED HOWEVER AS THE UPPER FLOW QUICKLY RETURNS SOUTHWESTERLY
AS ANOTHER POWERFUL SHORTWAVE TROUGH DIGS INTO WESTERN NORTH AMERICA
ON SUNDAY. THIS SHORTWAVE CARVES OUT A TROUGH ACROSS THE MOUNTAIN
WEST SUNDAY NIGHT INTO MONDAY.
A SERIES OF UPPER LEVEL SHORT WAVE TROUGHS WILL THEN RIPPLE
NORTHEAST IN THE SW FLOW ALOFT. SPECIFIC FEATURES ARE POORLY
RESOLVED BY MEDIUM RANGE MODELS BUT OVERALL TREND WILL BE A RETURN
TO INCREASING MOISTURE AS GULF OPENS BACK UP AGAIN. MEDIUM RANGE
MODELS ARE IN FAIRLY GOOD AGREEMENT IN CONCEPT IN SAGGING THE
SURFACE FRONTAL BOUNDARY SOUTH ACROSS THE LOCAL AREA MONDAY NIGHT
AND STALLING IT OUT TUESDAY SETTING THE STAGE FOR ANOTHER PROLONGED
PERIOD OF WET WEATHER TUESDAY INTO WEDNESDAY AS RIPPLES OF LOW
PRESSURE LIFT NORTHEAST ALONG THE BOUNDARY.
EF
&&
.HYDROLOGY...
350 PM CDT
WITH SFC DEW POINTS EXPECTED TO REACH INTO THE LOWER TO MIDDLE 60S
AND PWATS POSSIBLY REACHING AS HIGH AS 1.75 INCHES...ANY
THUNDERSTORMS THAT DEVELOP WILL BE EFFICIENT RAIN PRODUCERS. BASED
ON THE MATT BUNKERS PWAT CLIMATOLOGY...THESE VALUES APPROACH
RECORD LEVELS. SO...FLOODING WILL BE A MAJOR CONCERN FOR THE
ENTIRE CWA...WITH STORM TOTAL PCPN AMOUNTS OF 2-3 INCHES OVER THE
SERN PORTIONS OF THE CWA...GENERALLY SOUTH OF I-80...AND 3-4
INCHES TO THE NORTH. LATEST LOCAL QPF WOULD SUGGEST AN AREA OF
PCPN OF 4-5 INCHES IS POSSIBLE ALONG OVER NORTHERN ILLINOIS. THIS
REPRESENTS AN INCREASE OVER PREVIOUS FORECASTS...BUT GIVEN THE
RECORD LEVEL PWATS FOR AN EXTENDED PERIOD OF TIME...CONFIDENCE IS
INCREASING FOR THIS SIGNIFICANT RAINFALL. WITH MANY RIVERS AND
STREAMS ARE ALREADY NEAR OR ABOVE MINOR FLOOD STAGE...THIS AMOUNT
OF RAIN WILL BRING ADDITIONAL RISES TO MODERATE AND MAJOR FLOOD
LEVEL. IN ADDITION TO RIVER FLOODING...AREAL FLOODING OR
RURAL...SUBURBAN AND URBAN AREAS IS LIKELY...WITH LOW LYING ROADS
AND VIADUCTS FLOODING...AS WELL AS...ROADSIDE DRAINAGE DITCHES AND
DRAINAGE PONDS EXCEEDING CAPACITY. AREAS NOT SEEING FLOODING WILL
AT LEAST SEE AREAS OF STANDING OR PONDING WATER ON ROADS.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* WIDESPREAD SHRA AND TS TONIGHT.
* PERIODS OF VERY HEAVY RAINFALL THROUGH THE PERIOD...WITH LOW VIS
UNDER 2 MILES AT TIMES.
* LOW LEVEL WIND SHEAR THIS EARLY THIS MORNING WITH A 50 KT
SOUTHERLY JET AT 2,000 FT AGL.
* WINDS SHIFTING OUT OF THE SOUTH AFTER 10 UTC WITH WINDS LIKELY
GUSTING TO 30 TO 35 KT AT TIMES THROUGH MUCH OF THE DAY.
* TIMING OF IMPROVING CONDITIONS BY THIS EVENING.
KJB
//DISCUSSION...UPDATED 06Z...
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO TRAIN NORTHEASTWARD FROM
MISSOURI ACROSS NORTHERN ILLINOIS OVERNIGHT TONIGHT. MOISTURE
TRANSPORT IS ABSOLUTELY IMPRESSIVE...WITH A 50 TO 60KT LOW LEVEL JET
CONTINUALLY PUMPING IN DEEPER MOISTURE. PRECIPITABLE WATER VALUES
ARE PROGGED TO INCREASE TO NEAR 1.6 INCHES WHICH IS NEAR RECORD
VALUES FOR THIS TIME OF YEAR. THE COMBINATION OF THIS DEEP MOISTURE
AND THE THE STRONG DYNAMIC FORCING FROM THIS SYSTEM WILL CONTINUE TO
SUPPORT CONVECTIVE ACTIVITY. THERE COULD BE A VERY SHORT BREAK IN
THE ACTIVITY AROUND DAYBREAK AT THE EASTERN TERMINALS AS THE WARM
FRONT SURGES NORTHWARD THROUGH THE NIGHT. HOWEVER...CONFIDENCE IN THIS
IS LOW.
ANY BREAK IN THE ACTIVITY...WOULD BE SHORT LIVED...AS ADDITIONAL
THUNDERSTORMS WILL MAKE A RETURN BY MID TO LATE MORNING. VERY HEAVY
RAINFALL WILL LIKELY ACCOMPANY THESE THUNDERSTORMS. IT ALSO APPEARS
THAT SEVERAL HOURS OF ADDITIONAL THUNDERSTORM ACTIVITY IS LIKELY
FROM MID TO LATE MORNING THROUGH MUCH OF THE AFTERNOON AS THE CLOUD
BEARING FLOW LOOKS TO REMAIN PARALLEL TO THE APPROACHING SURFACE
BOUNDARY...WHICH SHOULD RESULT IN TRAINING CELLS. THIS HEAVY RAIN
WILL LIKELY REDUCE VISIBILITY UNDER 2 SM AT TIMES...ESPECIALLY
DURING THE AFTERNOON.
WINDS WILL RAPIDLY INCREASE OUT OF THE SOUTH BY EARLY MORNING AS THE
WARM FRONT LIFTS NORTH OF THE AREA. DUE TO THE PRESENCE OF 50 KT OF
FLOW ONLY A COUPLE THOUSAND FEET OFF THE GROUND...SOME OF THIS
MOMENTUM WILL LIKELY BE MIXED TO THE SURFACE. THUS WINDS WILL LIKELY
GUST IN THE LOW TO MID 30 KT RANGE FOR MUCH OF THE DAY. EVEN HIGH
WINDS WILL BE POSSIBLE IN WITHIN THE STRONGER STORMS.
THUNDERSTORM ACTIVITY SHOULD BEGIN TO ABATE ACROSS THE AREA BY LATE
AFTERNOON OR EARLY IN THE EVENING. HOWEVER...THE WINDS WILL SHIFT
OUT OF THE WEST SOUTHWEST BEHIND A COLD FRONT BY MID EVENING. THE
WINDS WILL LIKELY REMAIN GUSTY UP AROUND 30 KT BEHIND THIS
FRONT...BUT THE THREAT FOR THUNDER SHOULD END.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
HIGH CONFIDENCE IN PERIODS OF HEAVY THUNDERSTORM RAIN.
LOW TO MEDIUM CONFIDENCE ON TIMING OF IMPROVING CONDITIONS LATER
TODAY.
MODERATE TO HIGH CONFIDENCE IN WINDS.
HIGH CONFIDENCE IN IFR AND LOWER VIS AND CIGS IN +TSRA ACTIVITY.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...VFR...CHANCE SHRA WITH LOCAL MVFR.
SATURDAY...VFR...LAKE BREEZE DEVELOPING AND REACHING CHI TERMINALS
EARLY-MID AFTERNOON.
SUNDAY...VFR...SLIGHT CHANCE SHRA.
MONDAY...VFR...CHANCE SHOWERS.
TUESDAY...MVFR LOWERING TO IFR....CHANCE OF SHOWERS.
TRS
&&
.MARINE...
328 AM CDT
IT WILL BE A MESSY DAY ACROSS THE LAKE TODAY...WITH
THUNDERSTORMS...SOME STRONG TO SEVERE...AND STRONG SOUTHERLY WINDS
SOUTH...ESPECIALLY FOR THE NEAR SHORE WATERS. THE CURRENT NEAR SHORE
GALE WARNING LOOKS GOOD. HOWEVER...IT MIGHT BE HARD TO GET TO GALES
UP NEAR THE LAKE COUNTY ILLINOIS NEAR SHORE WATERS. THE STRONGEST
SOUTHERLY WINDS UP TO 40 KT IS EXPECTED ACROSS THE INDIANA NEAR
SHORE WATERS. ALTHOUGH THE WINDS WILL BE SCREAMING ONLY A COUPLE
HUNDRED FEET OFF THE WATER SURFACE...STABLE CONDITIONS OVER THE OPEN
WATERS SHOULD LIMIT THE AMOUNT OF THIS STRONG MOMENTUM ABLE TO MIX
TO THE WATER SURFACE...WITH THE EXCEPTION OF STRONG WINDS WITH ANY
STRONG THUNDERSTORMS.
A SURFACE LOW IS EXPECTED TO STRENGTHEN AND CONSOLIDATE ACROSS THE
WESTERN GREAT LAKES TODAY AND TONIGHT. THE TRACK OF THIS LOW SHOULD
BE SOMEWHERE ACROSS THE NORTHERN HALF OF THE LAKE THIS EVENING.
WHERE THIS LOW TRACKS THE WINDS WILL BE VARIABLE IN DIRECTION FOR A
PERIOD. THIS SYSTEM WILL PUSH A COLD FRONT ACROSS THE LAKE THROUGH
THE NIGHT TONIGHT. STRONG PRESSURE RISES AND COLD AIR ADVECTION
SHOULD RESULT IN THE DEVELOPMENT OF WESTERLY GALES VERY LATE TONIGHT
AND DURING THE DAY ON FRIDAY. IT CURRENTLY APPEARS THAT GALES OF 35
TO 40 KT ARE THE FAVORED WIND SPEEDS. THESE STRONG WINDS WILL ALSO
AFFECT THE NEAR SHORE WATERS AS WELL. I ISSUED A GALE WARNING FOR
THE OPEN WATERS FOR FRIDAY AND FRIDAY EVENING.
WINDS SHOULD ABATE ON SATURDAY AS A SURFACE RIDGE OF HIGH PRESSURE
BUILDS ACROSS THE GREAT LAKES. HOWEVER...THE WEATHER PATTERN LOOKS
TO BECOME ACTIVE AGAIN NEXT WEEK...WITH THE POTENTIAL FOR ANOTHER
SIGNIFICANT SYSTEM TO AFFECT THE GREAT LAKES REGION BY THE MIDDLE OF
NEXT WEEK.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 7 AM FRIDAY.
WIND ADVISORY...ILZ023-ILZ032-ILZ033-ILZ039...10 AM THURSDAY TO
7 PM THURSDAY.
IN...FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 AM
FRIDAY.
WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...10 AM
THURSDAY TO 7 PM THURSDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...4 AM FRIDAY TO 4 AM
SATURDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742...7 AM THURSDAY TO 7 PM
THURSDAY.
GALE WATCH...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...4 AM
FRIDAY TO 10 PM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 7 AM THURSDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...7 AM THURSDAY TO 10 PM
THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
708 AM CDT THU APR 18 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT THU APR 18 2013
THE PV1.5 ANOMALY CURRENTLY ACROSS WRN KS HAS SPAWNED ANOTHER
LOCALLY STRONG BUT NARROW BAND OF MODERATE SNOW. THIS BAND OF
SNOW WILL MOVE WITH THE ANOMALY AND THE RUC LIFTS IT NORTH
NORTHEAST VERY QUICKLY THIS MORNING. ACCUMULATING SNOWFALL COULD
BE OUT OF THE FCST BY 15Z AND HIGHEST ACCUMULATIONS...PERHAPS 4
INCHES...SHOULD FOCUS ALONG AND EAST OF HIGHWAY 281 INCLUDING
CUSTER COUNTY.
IT IS CLEAR THE DRY AIR IS WINNING OUT ON THIS SYSTEM AS THE SNOW
HAS SHUT OFF WEST OF HIGHWAY 61 ACROSS WRN NEB. THE RAP IS
SUGGESTING SOME SNOW SHOWER ACTIVITY TODAY AS THE 500 MB COLD
POOL MOVES OVERHEAD...ESPECIALLY TO THE LEE OF THE BLACK HILLS
WHERE A CONVERGENCE ZONE COULD DEVELOP. THE MODELS DO NOT FCST
THE LOCATION OF CONVERGENCE VERY WELL BUT THE RAP...GEM REG AND
NAM ARE SUGGESTING THE PANHANDLE SOUTH SOUTHEAST OF CHADRON. THE
FCST TODAY JUST BROAD BRUSHES ISOLATED SNOW SHOWERS WEST BUT
TAPERS THE SNOW OFF IN THE NORTHEAST.
THE NAM AND RAP SHOW SKIES CLEARING AROUND NIGHTFALL TONIGHT. THE
ARCTIC HIGH WILL BUILD THROUGH THE CNTL ROCKIES TONIGHT WHILE LOW
PRESSURE SWIRLS ACROSS THE UPPER MIDWEST ALLOWING FOR WINDS TO
STAY UP A BIT. THIS MIGHT HOLD LOWS NEAR 20 AND RADIATIONAL
CONDITIONS WILL BE LESS THAN IDEAL.
THE SNOW FCST IS FOR 1 TO 3 INCHES OF NEW SNOW TODAY. THIS USES
THE RUC QPF BUT REDUCES IT BY 70 PERCENT IN MOST AREAS AND
APPLIES A 10 TO 1 RATIO. THIS IS THE SAME AS REDUCING THE QPF BY
50 PERCENT AND USING A 14 TO 1 RATIO WHICH MIGHT BE CLOSER TO
REAL LIFE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 359 AM CDT THU APR 18 2013
FRIDAY WILL SEE HIGHS REBOUND BACK INTO THE 40S...NEAR 50 FOR FAR
SW NEB. HOWEVER NORTHWEST FLOW WILL BRING A DISTURBANCE ACROSS THE
NORTHERN PLAINS. MODELS SHOW SOME DECENT LOW LEVEL
SATURATION...WITH DRY AIR ALOFT. COULD SEE SOME DRIZZLE OR
SPRINKLES DURING THE DAY...HOWEVER JUST NOT ENOUGH CONFIDENCE TO
ADD YET...MAINLY DUE TO CURRENT CONDITIONS ON THE DRIER SIDE.
SATURDAY AND SUNDAY THE COUPLE MORE OF QUICK MOVING DISTURBANCES
WILL RIDE ACROSS NORTHERN/CENTRAL PLAINS. BETTER ENERGY IS TO THE
NORTH...HOWEVER WILL SEE THE SOUTHERN EDGE MOVE ACROSS THE CWA.
EXPECTING TO CONTINUE TO SEE COLD AIR ALOFT SPREAD DOWN FROM
CANADA...HOWEVER LESS MOISTURE TO WORK WITH IN THE LOWER LEVELS.
STRONGER COLD FRONT SUNDAY WITH GFS DEVELOPING SOME MARGINAL
CAPE...COUPLE HUNDRED J/KG...AND BARELY NEG LI/S AHEAD OF THE
FRONT. HAVE INTRODUCED ISOLD THUNDER DURING THE DAY...WHICH MAY
LINGER INTO THE EVENING DEPENDING ON EXACT TIMING OF THE FRONT
AND MOISTURE.
MONDAY AND TUESDAY ARE EXPECTED TO BE ANOTHER WELL BELOW NORMAL
COUPLE OF DAYS. GFS CAME IN COOLER...WHICH IS CLOSER TO THE
COOLER EC. HIGHS LIKELY IN THE 40S...WHICH WOULD NORMALLY BE A
STRETCH TO GO SO FAR BELOW NORMAL /NORMAL IS 60S/ THIS FAR OUT.
HOWEVER WITH THE LAST TWO SYSTEMS SHOWING HOW EASY IT IS TO
ACCOMPLISH THIS APRIL...WILL CONTINUE TO BE SOME 20 PLUS DEGREES
BELOW NORMAL FOR HIGHS. LOWS IN THE 20S SO LIGHT PRECIP IS
EXPECTED TO BE RAIN OR A MIX DURING THE DAY AND A MIX TO SNOW
OVERNIGHT.
WEDNESDAY WILL SEE THE START OF ANOTHER WARMUP AND DRY
CONDITIONS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 705 AM CDT THU APR 18 2013
SNOW CONTINUING OVER NORTH CENTRAL AND NORTHEAST NEBRASKA WILL
CONTINUE BRINGING AREAS OF CEILINGS BELOW 1000 FEET MSL AND
VISIBILITY AS LOW AS 1/2SM. THE SNOW WILL GRADUALLY DIMINISH
TODAY ALONG AND EAST OF AN ANW-BBW LINE. OTHER PARTS OF WESTERN
NEBRASKA INCLUDING LBF AND TIF WILL HAVE CEILINGS 1500-2500 FEET
AGL AND VISIBILITY OF 3SM OR LOWER UNTIL LATE THIS MORNING.
WIND IN CENTRAL AND WESTERN NEBRASKA WILL INCREASE TODAY AND
BECOME 310-340 AT 22-26G31-35KT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR
NEZ006>010-026>029-038.
&&
$$
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1228 AM CDT THU APR 18 2013
.SYNOPSIS...
ISSUED AT 256 PM CDT WED APR 17 2013
AT 19Z...WATER VAPOR IMAGERY CONTINUED SHOWING A DEEP TROUGH ACROSS
THE WESTERN STATES WITH THE AXIS RUNNING FROM LAKE WINNIPEG THROUGH
MONTANA...WYOMING AND UTAH TO SOUTHERN NEVADA. AT THE
SURFACE...THERE WAS A STRENGTHENING SURFACE LOW OVER CENTRAL NEW
MEXICO. A FRONT EXTENDED FROM THAT LOW ACROSS THE TEXAS RED RIVER
AREA THROUGH EASTERN OKLAHOMA AND SOUTHEAST KANSAS TO CENTRAL
MISSOURI. THERE WAS ALSO AND INVERTED TROUGH OR OCCLUDED FRONT
EXTENDING FROM THE NEW MEXICO LOW INTO SOUTH CENTRAL
COLORADO.
&&
.UPDATE...
ISSUED AT 948 PM CDT WED APR 17 2013
A NEW FORECAST IS OUT USING THE RAP AND ARF MODELS. STILL LOOKS
LIKE AREAS EAST OF HIGHWAY 83 WILL MEASURE 3 TO 6 INCHES BY
THURSDAY AFTN. WEST OF 83...THE SNOW IS SHOWING SIGNS OF WINDING
DOWN. SATELLITE AND THE RAP MODEL SHOW TO DISTINCT AREAS OF
POTENTIAL VORTICITY. ONE NEAR DODGE CITY WHICH IS IGNITING
CONVECTION. SLEET AND SNOW SHOULD DEVELOP AS THIS AREA MOVES NORTH
NORTHEAST BRUSHING EASTERN ZONES WITH SNOW AFTER MIDNIGHT. MOST OF
THIS SNOW SHOULD END UP ACROSS CNTL NEB. THE SECOND AREA OF
POTENTIAL VORTICITY LIES ACROSS ERN NEW MEXICO. THIS ARE IS
EXPECTED TO IGNITE A SECOND BAND OF MODERATE SNOW ALONG AND EAST
OF HIGHWAY 83 LATE TONIGHT AND THURSDAY. MOST OF THIS SNOW SHOULD
FALL EAST OF HIGHWAY 83. THUS 2 TO 4 INCHES IS EXPECTED WEST OF
HIGHWAY 83 WITH THE EMPHASIS ON 2 INCHES GIVEN THE RADAR TRENDS
AND SIGNS OF DRY AIR WORKING SOUTHWARD THROUGH SOUTH DAKOTA.
WINDS ARE ABOUT 10 KTS LESS THAN PREVIOUSLY FORECAST BUT STRONGEST
WINDS COULD DEVELOP LATE THURSDAY MORNING AND AFTERNOON. THE REST
OF THE FORECAST IS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 256 PM CDT WED APR 17 2013
AREAS OF FREEZING DRIZZLE THIS MORNING LOOKS TO BE TRANSITIONING
MORE TO LIGHT FOG AND VERY LIGHT SNOW ACROSS THE CENTRAL SANDHILLS
AND EASTERN AREAS THIS AFTERNOON AS COLDER AIR CONTINUES TO SETTLE
SOUTHWARD. ONLY AREA WITH LIGHT SNOW ACCUMULATIONS THIS AFTERNOON IS
ACROSS SHERIDAN AND NORTHWEST CHERRY COUNTY.
THE 700MB CLOSED LOW WAS LOCATED IN CENTRAL COLORADO AT 18Z TODAY.
SNOW EXTENDS ACROSS THE COLORADO MOUNTAINS AND EASTERN FOOTHILLS
INTO SOUTHEAST WYOMING THE NEBRASKA PANHANDLE AND SOUTHWEST SOUTH
DAKOTA. MEANWHILE SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS
CENTRAL AND NORTHEAST KANSAS INTO FAR SOUTHEAST NEBRASKA SOUTHWEST
IOWA. STRONG STORMS DEVELOPING WEST CENTRAL OKLAHOMA/SOUTH CENTRAL
KANSAS. THE UPPER LOW IS FORECAST TO LIFT NORTHEAST AS A POSITIVELY
TILT INTO NORTHWEST KANSAS/CENTRAL NEBRASKA BY 06Z THURSDAY.
MODERATE TO LOCALLY HEAVY SNOW IS FAVORED TO DEVELOP ALONG AND WEST
OF THE UPPER LOW. THE GFS IS AND HAS CONSISTENTLY BEEN MORE ROBUST
WITH QPFS THE PAST SEVERAL RUNS...WHILE THE NAM HAS SLOWLY BEEN
COMING INTO LINE. ONE CONCERN WILL BE CONVECTION TO OUR SOUTHEAST
THIS AFTERNOON/TONIGHT WHICH MAY LIMIT MOISTURE TRANSPORT INTO
WESTERN NEBRASKA TONIGHT INTO THURSDAY. HAVE TAKEN THIS INTO ACCOUNT
WITH THE FORECAST. SECOND CONCERN WILL BE WINDS WITH NORTH WINDS
THIS EVENING 20 TO 35 MPH BACKING TO THE NORTHWEST AFTER MIDNIGHT.
THEN ON THURSDAY...NORTHWEST WINDS TO INCREASE TO 25 TO 35 MPH WITH
GUSTS TO 40 MPH. WINDS TONIGHT AND THURSDAY WILL CAUSE BLOWING AND
DRIFTING SNOW ACROSS THE SOUTHERN AND EASTERN HALF OF THE AREA
THROUGH THURSDAY. IN THE WINTER WEATHER ADVISORY AREA...SNOWFALL
AMOUNTS TONIGHT AND THURSDAY RANGE FROM 3 TO 5 INCHES SOUTHWEST
NEBRASKA...4 TO 7 INCHES EAST OF VALENTINE THROUGH BROKEN BOW.
ACROSS THE NORTHWEST AROUND 6 INCHES POSSIBLE. WILL CARRY ALL
EXISTING WINTER STORM WARNINGS AND ADVISORY THROUGH TONIGHT. ONLY
CHANGE WAS TO EXTEND THE ADVISORY THROUGH THE DAY THURSDAY ACROSS
THE EASTERN HALF OF THE FORECAST AREA DUE TO THE SLOWER TIMING OF
THE SYSTEM AND EXPECTED WRAP AROUND SNOW.
THE STRONG NORTHWEST WINDS WITH HIGH TEMPERATURES ONLY IN THE LOWER
30S MOST AREAS THURSDAY TO RESULT IN WIND CHILL VALUES OF 5 TO 15
ABOVE IN THE MORNING AND 15 TO 20 DEGREES IN THE AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 256 PM CDT WED APR 17 2013
WARM AIR RETURNING FROM THE SOUTHWEST FRIDAY EVENING WILL GENERATE
SOME DEEP ISENTROPIC UPGLIDE OF NEARLY SATURATED AIR IN THE 290-310K
LAYER. THE BOUNDARY LAYER IS PRETTY DRY THOUGH...SO SIGNIFICANT
PRECIPITATION IS NOT LIKELY.
A FRONT SETTLES INTO THE NORTHERN PLAINS SATURDAY AND THEN BEGINS
MOVING NORTH AND SOUTH ALTERNATELY. THIS WILL KEEP SOME CHANCE OF
PRECIPITATION IN CENTRAL AND WESTERN NEBRASKA SATURDAY EVENING
THROUGH TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1227 AM CDT THU APR 18 2013
MIXED IFR/MVFR/VFR CONTINUES OVERNIGHT WITH IMPROVEMENT TO
VFR/MVFR FROM WEST TO EAST. THIS PROCESS IS ALREADY UNDERWAY
ACROSS WRN NEB. THE RAP IS SUGGESTING LOCAL IFR ACROSS WRN NEB
THURSDAY AFTERNOON AS SCATTERED -SHSN DEVELOP. EAST OF HIGHWAY
83...IFR/MVFR MAY CONTINUE THROUGH THURSDAY AFTERNOON IN SNOW AND BLSN.
IMPROVEMENT TO WIDESPREAD VFR IS EXPECTED ALL AREAS BETWEEN 00Z
THURSDAY AND 06Z THURSDAY EVENING AS THE UPPER LEVEL LOW ACROSS
THE SRN ROCKIES EJECTS INTO THE MIDWEST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ THIS MORNING
FOR NEZ004-022>024-035-036-056>058-069-070-094.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR NEZ005-
025-037-059-071.
WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR
NEZ006>010-026>029-038.
&&
$$
UPDATE...CDC
SYNOPSIS...SPRINGER
SHORT TERM...ROBERG
LONG TERM...SPRINGER
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
740 AM EDT THU APR 18 2013
.SYNOPSIS...
A WARM FRONT WILL APPROACH THE REGION TODAY...AND THEN MOVE NORTH
INTO CANADA TONIGHT. IT WILL BE WARM AND BECOMING WINDY TODAY AND
FRIDAY AS GUSTY SOUTHERLY WINDS WILL BRING MUCH WARMER AIR TO THE
NORTH COUNTRY...WITH HIGHS IN THE 70S ON FRIDAY. A COLD FRONT WILL
MOVE INTO THE REGION LATE FRIDAY AFTERNOON AND THEN MOVE ACROSS
THE AREA FRIDAY NIGHT...BRINGING RAIN SHOWERS TO THE NORTH
COUNTRY. IT WILL BE MUCH COOLER AND BREEZY ON SATURDAY. A HIGH
PRESSURE AREA OVER THE GREAT LAKES WILL BUILD INTO THE REGION
SATURDAY NIGHT AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 740 AM EDT THURSDAY...COMPOSITE RADAR LOOP SHOWING SOME
RETURNS ACROSS NORTHERN NEW YORK AND THE NORTHERN CHAMPLAIN VALLEY
AT THIS TIME. HAVE RAISED POPS TO SLIGHT CHANCE FOR SHOWERS FOR
TODAY...BUT NOT EXPECTING MUCH IF ANY IN THE WAY OF
ACCUMULATIONS...AS TEMPERATURE/DEW POINT SPREAD WILL INCREASE
DURING THE DAY. EXPECTING MAINLY SPRINKLES TODAY...IF ANYTHING
REACHES THE SURFACE. OTHERWISE...THE FORECAST IS IN GOOD SHAPE.
PREVIOUS DISCUSSION FROM 451 AM EDT THURSDAY...WARM FRONT WILL
LIFT NORTHEAST THROUGH THE REGION TODAY BRINGING CLOUDS...ALONG
WITH A CHANCE OF RAIN SHOWERS MAINLY OVER THE SAINT LAWRENCE
VALLEY AND THE ADIRONDACKS. TEMPERATURES WILL CLIMB TO THE UPPER
50S TO LOWER 60S TODAY. SURFACE PRESSURE GRADIENT TO TIGHTEN THIS
AFTERNOON...SO COULD SEE SOME SOUTHERLY WIND GUSTS UP TO 40 MPH
POSSIBLE THIS AFTERNOON FROM THE CHAMPLAIN VALLEY WESTWARD ACROSS
NORTHERN NEW YORK. MOS POPS LOOK TOO HIGH FOR TODAY...SO HAVE
LOWERED THEM QUITE A BIT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
AS OF 451 AM EDT THURSDAY...THE WARM FRONT WILL LIFT NORTHEAST
INTO QUEBEC TONIGHT. HAVE GONE WITH A DRY FORECAST FOR TONIGHT...
AS THE BEST LIFT ASSOCIATED WITH THE WARM FRONT WILL BE IN CANADA.
THUS...HAVE GREATLY LOWERED MOS POPS FOR TONIGHT. GUSTY SOUTHERLY
WINDS WILL CONTINUE INTO TONIGHT...AND THIS WILL HELP TO KEEP
TEMPERATURES UP TONIGHT. HAVE GONE SEVERAL DEGREES WARMER THAN THE
GFS MOS GUIDANCE FOR MIN TEMPERATURES TONIGHT. ON FRIDAY...GUSTY
SOUTHERLY WINDS WILL CONTINUE AS SURFACE PRESSURE GRADIENT REMAINS
TIGHT ACROSS THE REGION. SOUTHERLY WIND GUSTS COULD APPROACH 50
MPH FRIDAY AFTERNOON ACROSS WESTERN VERMONT AND NORTHERN NEW YORK.
GIVEN THAT THIS WILL OCCUR LATE IN THE THIRD PERIOD OF THE
FORECAST...HAVE HELD OFF ON ANY WIND ADVISORY AT THIS TIME. WILL
LET LATER SHIFTS REVIEW LATER GUIDANCE BEFORE MAKING ANY DECISION
ON A WIND ADVISORY. HAVE MENTIONED THIS POSSIBILITY IN THE
HAZARDOUS WEATHER OUTLOOK PRODUCT. EXPECTING FRIDAY TO START OUT
AS A MAINLY DRY DAY ACROSS THE REGION WITH TEMPERATURES CLIMBING
INTO THE 70S FRIDAY AFTERNOON. THE BEST CHANCE FOR RAIN SHOWERS
FOR LATER FRIDAY AFTERNOON WILL BE ACROSS THE SAINT LAWRENCE
VALLEY AND THE ADIRONDACKS IN NORTHERN NEW YORK...AS THE COLD
FRONT MOVES INTO THE REGION. HAVE HELD OFF ON BRINGING RAIN
SHOWERS FOR THE CHAMPLAIN VALLEY AND VERMONT UNTIL FRIDAY NIGHT.
MODELS SHOW A MID LEVEL DRY SLOT WILL WORK INTO THE REGION LATE
FRIDAY NIGHT...SO EXPECTING ANY RAIN SHOWER ACTIVITY WILL COME TO
AN END BEFORE DAYBREAK ON SATURDAY. MUCH COOLER TEMPERATURES WILL
BE OVER THE REGION ON SATURDAY. HAVE PUT IN SLIGHT CHANCE POPS
OVER THE MOUNTAINS FOR RAIN SHOWERS ON SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 510 AM EDT THURSDAY...OVERALL GOOD AGREEMENT BTWN GFS/ECMWF
FOR THE WEEKEND AND INTO EARLY NEXT WK...THEN UNCERTAINTY DEVELOPS
AS PATTERN BECMG MORE ACTIVE. SFC HIGH PRES WL RESULT IN MAINLY
CLR SKIES AND DRY CONDITIONS FOR SUNDAY/MONDAY. GIVEN DEEP DRY
AIRMASS ACRS THE NE CONUS...EXPECT LARGE SWINGS IN DIURNAL TEMPS
FROM LOWS SAT NIGHT/SUNDAY NIGHT TO HIGHS ON SUNDAY/MONDAY. TEMPS
WL BE 4 TO 8 DEGREES BLW NORMAL. THE 00Z ECMWF HAS TRENDED TWD THE
GFS/GFS ENSEMBLE AND GEM FOR TUESDAY...WITH TRACK WELL TO OUR
SOUTH AND EAST. GIVEN UNCERTAINTY WITH ANTICYCLONIC FLW AROUND
HIGH PRES AND POTENTIAL FOR SOME MOISTURE TO ADVECT BACK INTO OUR
CENTRAL/EASTERN CWA WL MENTION SCHC/LOW CHC POPS. ALSO...THIS WL
CONT WITH PREVIOUS FCSTER THINKING. OTHERWISE...MODELS ARE IN
RELATIVELY GOOD AGREEMENT WITH NEXT LARGE SCALE SYNOPTIC SYSTEM
IMPACTING OUR REGION LATE WEDS INTO THURS. ONCE AGAIN SFC LOW PRES
WL TRACK TO OUR WEST...PLACING OUR CWA IN THE WARM SECTOR BY WEDS
ALONG CHCS FOR PRECIP WED AFTN INTO THURS. TEMPS WL BE NEAR NORMAL
TUES AND ABOVE NORMAL FOR WEDS INTO THURS.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
THROUGH 12Z FRIDAY...DEVELOPING STRONG SOUTHERLY SFC WINDS WILL
CREATE AREAS OF MODERATE TURBULENCE AND AREAS OF POTENTIAL LLVL
WIND SHEAR TODAY. AVIATION CHALLENGE THRU THIS EVENING WL BE
PLACEMENT OF LIGHT RAIN SHOWERS THIS MORNING...FOLLOWED BY GUSTY
WINDS. CRNT SFC ANALYSIS SHOWS HIGH PRES LOCATED OVER NORTHERN NEW
ENGLAND WITH A SFC WARM FRNT LIFTING ACRS NORTHERN NY ATTM. THIS
FRNT AND ASSOCIATED RIBBON OF DEEPER MOISTURE WL LIFT ACRS
NORTHERN NY TAF SITES BTWN 12Z AND 15Z THIS MORNING. BASED OFF THE
RAP 13 HAVE TEMPO A PERIOD OF -SHRA FOR MSS/SLK EARLY THIS
MORNING. WL USE VCSH AT PBG/BTV BTWN 13-16Z. IN ADDITION...SFC
GRADIENT WL INCREASE WITH GUSTY SOUTH WINDS ANTICIPATED. SOUNDINGS
SHOW WIND GUSTS POTENTIAL BTWN 25 AND 30 KNTS THIS AFTN...AS SFC
HEATING OCCURS. RAP SOUNDINGS SHOW GUST POTENTIAL BTWN 35 ADN 40
KNTS AT MSS/BTV/SLK BTWN 19Z AND 02Z TODAY. VFR CONDITIONS WL
PREVAIL THRU TODAY. NAM AND RAP CONTS TO SHOW SOME LLVL RH/CLOUDS
INCREASING THIS EVENING WITH THE POTENTIAL FOR SOME MVFR CIGS IN A
STRATO CUMULUS DECK...NOT ANTICIPATING FOG/BR GIVEN LLVL WIND
PROFILES...WL USE SCATTERED 1200 TO 1500 FT TO SHOW THIS POTENTIAL
OUTLOOK 12Z FRIDAY THROUGH MONDAY... GUSTY SOUTHERLY WINDS WL CONT
ON FRIDAY AS SFC LOW PRES TRACKS FROM THE GREAT LAKES INTO CENTRAL
CANADA. A BROKEN LINE OF SHOWERS WL IMPACT OUR TAF SITES LATE
FRIDAY INTO SATURDAY WITH A BRIEF PERIOD OF MVFR CONDITIONS
POSSIBLE IN THE HEAVIER SHOWERS. OTHERWISE...SFC HIGH PRES AND VFR
CONDITIONS PREVAIL SAT THRU EARLY NEXT WEEK.
&&
.HYDROLOGY...
AS OF 451 AM EDT THURSDAY...WARMER TEMPERATURES TODAY AND FRIDAY
WILL RESULT IN MELTING SNOW ACROSS THE HIGHER ELEVATIONS OF THE
ADIRONDACKS AND GREEN MOUNTAINS. RUNOFF FROM THIS SNOW MELT WILL
LEAD TO SOME SHARP RISES ON AREA RIVERS TODAY THROUGH FRIDAY.
HOWEVER...NO FLOODING IS EXPECTED AT THIS TIME.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH
NEAR TERM...WGH
SHORT TERM...WGH
LONG TERM...TABER
AVIATION...TABER
HYDROLOGY...WGH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
714 AM EDT THU APR 18 2013
.SYNOPSIS...
A WARM FRONT WILL APPROACH THE REGION TODAY...AND THEN MOVE NORTH
INTO CANADA TONIGHT. IT WILL BE WARM AND BECOMING WINDY TODAY AND FRIDAY
AS GUSTY SOUTHERLY WINDS WILL BRING MUCH WARMER AIR TO THE
NORTH COUNTRY...WITH HIGHS IN THE 70S ON FRIDAY. A COLD FRONT
WILL MOVE INTO THE REGION LATE FRIDAY AFTERNOON AND THEN MOVE
ACROSS THE AREA FRIDAY NIGHT...BRINGING RAIN SHOWERS TO THE NORTH
COUNTRY. IT WILL BE MUCH COOLER AND BREEZY ON SATURDAY. A HIGH
PRESSURE AREA OVER THE GREAT LAKES WILL BUILD INTO THE REGION
SATURDAY NIGHT AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 451 AM EDT THURSDAY...A WARM FRONT WILL LIFT NORTHEAST
THROUGH THE REGION TODAY BRINGING CLOUDS...ALONG WITH A CHANCE OF
RAIN SHOWERS MAINLY OVER THE SAINT LAWRENCE VALLEY AND THE
ADIRONDACKS. TEMPERATURES WILL CLIMB TO THE UPPER 50S TO LOWER 60S
TODAY. SURFACE PRESSURE GRADIENT TO TIGHTEN THIS AFTERNOON...SO
COULD SEE SOME SOUTHERLY WIND GUSTS UP TO 40 MPH POSSIBLE THIS
AFTERNOON FROM THE CHAMPLAIN VALLEY WESTWARD ACROSS NORTHERN NEW
YORK. MOS POPS LOOK TOO HIGH FOR TODAY...SO HAVE LOWERED THEM
QUITE A BIT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
AS OF 451 AM EDT THURSDAY...THE WARM FRONT WILL LIFT NORTHEAST
INTO QUEBEC TONIGHT. HAVE GONE WITH A DRY FORECAST FOR TONIGHT...
AS THE BEST LIFT ASSOCIATED WITH THE WARM FRONT WILL BE IN CANADA.
THUS...HAVE GREATLY LOWERED MOS POPS FOR TONIGHT. GUSTY SOUTHERLY
WINDS WILL CONTINUE INTO TONIGHT...AND THIS WILL HELP TO KEEP
TEMPERATURES UP TONIGHT. HAVE GONE SEVERAL DEGREES WARMER THAN THE
GFS MOS GUIDANCE FOR MIN TEMPERATURES TONIGHT. ON FRIDAY...GUSTY
SOUTHERLY WINDS WILL CONTINUE AS SURFACE PRESSURE GRADIENT REMAINS
TIGHT ACROSS THE REGION. SOUTHERLY WIND GUSTS COULD APPROACH 50
MPH FRIDAY AFTERNOON ACROSS WESTERN VERMONT AND NORTHERN NEW YORK.
GIVEN THAT THIS WILL OCCUR LATE IN THE THIRD PERIOD OF THE
FORECAST...HAVE HELD OFF ON ANY WIND ADVISORY AT THIS TIME. WILL
LET LATER SHIFTS REVIEW LATER GUIDANCE BEFORE MAKING ANY DECISION
ON A WIND ADVISORY. HAVE MENTIONED THIS POSSIBILITY IN THE
HAZARDOUS WEATHER OUTLOOK PRODUCT. EXPECTING FRIDAY TO START OUT
AS A MAINLY DRY DAY ACROSS THE REGION WITH TEMPERATURES CLIMBING
INTO THE 70S FRIDAY AFTERNOON. THE BEST CHANCE FOR RAIN SHOWERS
FOR LATER FRIDAY AFTERNOON WILL BE ACROSS THE SAINT LAWRENCE
VALLEY AND THE ADIRONDACKS IN NORTHERN NEW YORK...AS THE COLD
FRONT MOVES INTO THE REGION. HAVE HELD OFF ON BRINGING RAIN
SHOWERS FOR THE CHAMPLAIN VALLEY AND VERMONT UNTIL FRIDAY NIGHT.
MODELS SHOW A MID LEVEL DRY SLOT WILL WORK INTO THE REGION LATE
FRIDAY NIGHT...SO EXPECTING ANY RAIN SHOWER ACTIVITY WILL COME TO
AN END BEFORE DAYBREAK ON SATURDAY. MUCH COOLER TEMPERATURES WILL
BE OVER THE REGION ON SATURDAY. HAVE PUT IN SLIGHT CHANCE POPS
OVER THE MOUNTAINS FOR RAIN SHOWERS ON SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 510 AM EDT THURSDAY...OVERALL GOOD AGREEMENT BTWN GFS/ECMWF
FOR THE WEEKEND AND INTO EARLY NEXT WK...THEN UNCERTAINTY DEVELOPS
AS PATTERN BECMG MORE ACTIVE. SFC HIGH PRES WL RESULT IN MAINLY
CLR SKIES AND DRY CONDITIONS FOR SUNDAY/MONDAY. GIVEN DEEP DRY
AIRMASS ACRS THE NE CONUS...EXPECT LARGE SWINGS IN DIURNAL TEMPS
FROM LOWS SAT NIGHT/SUNDAY NIGHT TO HIGHS ON SUNDAY/MONDAY. TEMPS
WL BE 4 TO 8 DEGREES BLW NORMAL. THE 00Z ECMWF HAS TRENDED TWD THE
GFS/GFS ENSEMBLE AND GEM FOR TUESDAY...WITH TRACK WELL TO OUR
SOUTH AND EAST. GIVEN UNCERTAINTY WITH ANTICYCLONIC FLW AROUND
HIGH PRES AND POTENTIAL FOR SOME MOISTURE TO ADVECT BACK INTO OUR
CENTRAL/EASTERN CWA WL MENTION SCHC/LOW CHC POPS. ALSO...THIS WL
CONT WITH PREVIOUS FCSTER THINKING. OTHERWISE...MODELS ARE IN
RELATIVELY GOOD AGREEMENT WITH NEXT LARGE SCALE SYNOPTIC SYSTEM
IMPACTING OUR REGION LATE WEDS INTO THURS. ONCE AGAIN SFC LOW PRES
WL TRACK TO OUR WEST...PLACING OUR CWA IN THE WARM SECTOR BY WEDS
ALONG CHCS FOR PRECIP WED AFTN INTO THURS. TEMPS WL BE NEAR NORMAL
TUES AND ABOVE NORMAL FOR WEDS INTO THURS.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
THROUGH 12Z FRIDAY...DEVELOPING STRONG SOUTHERLY SFC WINDS WILL
CREATE AREAS OF MODERATE TURBULENCE AND AREAS OF POTENTIAL LLVL
WIND SHEAR TODAY. AVIATION CHALLENGE THRU THIS EVENING WL BE
PLACEMENT OF LIGHT RAIN SHOWERS THIS MORNING...FOLLOWED BY GUSTY
WINDS. CRNT SFC ANALYSIS SHOWS HIGH PRES LOCATED OVER NORTHERN NEW
ENGLAND WITH A SFC WARM FRNT LIFTING ACRS NORTHERN NY ATTM. THIS
FRNT AND ASSOCIATED RIBBON OF DEEPER MOISTURE WL LIFT ACRS
NORTHERN NY TAF SITES BTWN 12Z AND 15Z THIS MORNING. BASED OFF THE
RAP 13 HAVE TEMPO A PERIOD OF -SHRA FOR MSS/SLK EARLY THIS
MORNING. WL USE VCSH AT PBG/BTV BTWN 13-16Z. IN ADDITION...SFC
GRADIENT WL INCREASE WITH GUSTY SOUTH WINDS ANTICIPATED. SOUNDINGS
SHOW WIND GUSTS POTENTIAL BTWN 25 AND 30 KNTS THIS AFTN...AS SFC
HEATING OCCURS. RAP SOUNDINGS SHOW GUST POTENTIAL BTWN 35 ADN 40
KNTS AT MSS/BTV/SLK BTWN 19Z AND 02Z TODAY. VFR CONDITIONS WL
PREVAIL THRU TODAY. NAM AND RAP CONTS TO SHOW SOME LLVL RH/CLOUDS
INCREASING THIS EVENING WITH THE POTENTIAL FOR SOME MVFR CIGS IN A
STRATO CUMULUS DECK...NOT ANTICIPATING FOG/BR GIVEN LLVL WIND
PROFILES...WL USE SCATTERED 1200 TO 1500 FT TO SHOW THIS POTENTIAL
OUTLOOK 12Z FRIDAY THROUGH MONDAY... GUSTY SOUTHERLY WINDS WL CONT
ON FRIDAY AS SFC LOW PRES TRACKS FROM THE GREAT LAKES INTO CENTRAL
CANADA. A BROKEN LINE OF SHOWERS WL IMPACT OUR TAF SITES LATE
FRIDAY INTO SATURDAY WITH A BRIEF PERIOD OF MVFR CONDITIONS
POSSIBLE IN THE HEAVIER SHOWERS. OTHERWISE...SFC HIGH PRES AND VFR
CONDITIONS PREVAIL SAT THRU EARLY NEXT WEEK.
&&
.HYDROLOGY...
AS OF 451 AM EDT THURSDAY...WARMER TEMPERATURES TODAY AND FRIDAY
WILL RESULT IN MELTING SNOW ACROSS THE HIGHER ELEVATIONS OF THE
ADIRONDACKS AND GREEN MOUNTAINS. RUNOFF FROM THIS SNOW MELT WILL
LEAD TO SOME SHARP RISES ON AREA RIVERS TODAY THROUGH FRIDAY.
HOWEVER...NO FLOODING IS EXPECTED AT THIS TIME.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH
NEAR TERM...WGH
SHORT TERM...WGH
LONG TERM...TABER
AVIATION...TABER
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
415 AM EDT THU APR 18 2013
.SYNOPSIS...
A WARM FRONT WILL MOVE THROUGH THE REGION TODAY...BRINGING
MILDER TEMPERATURES THROUGH FRIDAY. A STRONG COLD FRONT IS
EXPECTED TO CROSS THE AREA FRIDAY EVENING ACCOMPANIED BY
SHOWERS...AND A CHANCE OF THUNDERSTORMS. COOLER TEMPERATURES WILL
FOLLOW AGAIN THIS WEEKEND UNDER FAIR SKIES.
&&
.NEAR TERM /THROUGH 6 PM TODAY/...
SHORT TERM GUIDANCE FROM THE NAM/GFS/WRF AND RAP MODELS ARE IN
GOOD AGREEMENT TODAY...AND SUGGEST A MILD SURGE OF AIR
OVERSPREADING THE REGION ASSOCIATED WITH A WARM FRONTAL PASSAGE
ALOFT. LOW LEVEL MOISTURE NOTED WITHIN A MARINE LAYER EXTENDING
NORTHWARD FROM THE MID-ATLANTIC STATES WILL MARR THE MILD FORECAST
WITH AN ABUNDANCE OF CLOUDS TODAY. PREVIOUS FORECAST INCLUDED
PATCHY DRIZZLE...HOWEVER THE ISENTROPIC LIFT ASSOCIATED WITH THE
WARM FRONTAL BOUNDARY LOOKS TO BE FOCUSED WELL TO OUR NORTH ALONG
THE 850 MB FRONTAL ZONE. THIS LEAVES MAINLY OROGRAPHIC EFFECTS TO
SQUEEZE OUT ANY LIGHT PRECIP. THIS IS NOT TYPICALLY FAVORABLE
DURING THE WELL MIXED DAYLIGHT HOURS...AND WE EXPECT CLOUD
CEILINGS TO BE MODESTLY HIGH TODAY AND NOT CONDUCIVE TO DRIZZLE.
DECIDED TO REMOVE MENTION OF PTCHY DRIZZLE FOR TODAY.
&&
.SHORT TERM /6 PM TONIGHT THROUGH SATURDAY NIGHT/...
THE SOUTH-SOUTHEASTERLY FLOW IMPINGING ON OUR HIGHER TERRAIN
TONIGHT...ALONG WITH BOUNDARY LAYER COOLING AND SATURATION SEEMS
TO OFFER THE BETTER OPPORTUNITY FOR DRIZZLE AFTER DARK. WILL KEEP
THAT IN THE FORECAST ACROSS THE SOUTHERN TIER NY AND NEPA...AND
REFINE THE FORECAST TO FEATURE DRIZZLE MAINLY OVER THE ELEVATIONS
ABOVE 1200-1500 FEET.
THE MORE INTERESTING PART OF THE FORECAST OCCURS LATER FRIDAY
AFTERNOON AS THE MAIN COLD FRONT OF THE APPROACHING STORM SYSTEM
CROSSES THE REGION. MODEL SOLUTIONS ARE CONSISTENT AND MAINTAIN
THAT THE BULK OF RAIN ACTIVITY WILL BE BETWEEN ABOUT 21Z AND 02Z.
FORECAST WIND PROFILES ARE IMPRESSIVE BOTH IN SPEED AND DIRECTIONAL
SHEAR...BUT INSTABILITY IS WEAK WITHIN A MODERATELY MOIST ADIABATIC
ENVIRONMENT. A FEW HUNDRED J/KG OF CAPE IS ENOUGH TO WARRANT
MENTION OF THUNDER...BUT A SVR THREAT AT THIS TIME SEEMS LOW WITH
THE EXPECTATION OF AN ABUNDANCE OF LOW CLOUD COVER LIMITING THE DIURNAL
HEATING. THE SPC INDICATES GENERAL THUNDER FOR THE REGION BUT NO
MENTION OF SVR. GRADIENT SYNOPTIC WINDS DO LOOK BLUSTERY IN THE
15-30 MPH RANGE...BUT AT THIS TIME SHOULD REMAIN SAFELY UNDER ANY
KIND OF IMPACT THRESHOLDS.
FRONTAL PASSAGE FRIDAY EVENING WILL USHER A GOOD SHOT OF RAIN AND
THEN SOME MARKEDLY COLDER AIR HEADING INTO THE WEEKEND WITH
OVERNIGHT TEMPS IN THE 30S AND A REBOUND ON SATURDAY ONLY INTO THE 40S.
AM NOT TOO EXCITED ABOUT ANY LAKE RESPONSE...HOWEVER COLD
ADVECTION CLOUDINESS IS EXPECTED INTO SATURDAY MORNING DESPITE
SOME PRONOUNCED DRYING IN THE 1000-500 MB MEAN RH LAYER DEPICTED
BY THE MODELS. HIGH PRESSURE BUILDS IN QUICKLY FOR SATURDAY WITH
IMPROVING CONDITIONS AND EVENTUALLY CLEARING SKIES HEADING INTO
SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
300 AM UPDATE...LATEST GFS/ECMWF, SHOWS THE ECMWF IN BETTER
AGREEMENT WITH THE GFS, INDICATING A WEAKER AND FARTHER OUT TO
SEA SFC LOW ALONG THE EAST COAST TUE/WED. CURRENT EXTENDED IN
GOOD SHAPE, WILL CONTINUE WITH CHC/SLIGHT CHC POPS TUE THROUGH
WEDNESDAY.
PREVIOUS DISC...
A FAIRLY QUIET PERIOD SHAPING UP FOR THE FIRST HALF OF THE
EXTENDED PERIOD AS HIGH PRESSURE QUICKLY BUILDS IN FOLLOWING THE EARLY
WEEKEND COLD FRONT. WITH ITS ARRIVAL...COOLER AIR WILL BE IN STORE
WITH HIGHS ONLY EXPECTED TO WARM INTO THE UPPER 40S TO LOWER 50S
ON SUNDAY. NEXT WX FEATURE OF INTEREST WILL BE A NORTHWARD LIFTING
AREA OF LOW PRESSURE ALONG THE EASTERN SEABOARD WHICH THE ECMWF
SHOWS MOVING INTO THE AREA SOMETIME DURING THE DAY ON TUESDAY. THE
GFS ON THE OTHER HAND KEEPS THIS FEATURE WELL OFFSHORE WITH LITTLE
TO NO IMPACT ON OUR AREA. FOR NOW...WILL MAINTAIN SLGT CHC TO CHC
MENTION FOR OUR FCST AREA BEGINNING TUE WITH THIS TREND CONTINUING
THROUGH THE CONCLUSION OF THE PERIOD AS BOTH THE GFS AND ECMWF
SHOW THE NEXT WX SYSTEM/COLD FRONT APPROACHING FROM THE WEST BY
MIDWEEK. NO SIGNIFICANT DEVIATIONS FROM HPC GUIDANCE.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
A SFC WARM FRONT SOUTH OF THE REGION WILL LIFT NORTH THROUGH THE
AREA LATER TODAY AND THIS EVENING. MOISTURE FROM THIS BOUNDARY
AND INCREASING SOUTHEAST FLOW WILL LOWER CIGS TO AROUND 4K FT
BETWEEN 09Z-14Z THIS MORNING. CIGS WILL REMAIN AROUND THIS HEIGHT
THROUGH THE DAY. THIS EVENING CIGS AT KAVP/KELM/KBGM/KITH WILL
LIKELY LOWER INTO THE MVFR CATEGORY. LIGHT DRIZZLE IS ALSO
POSSIBLE OVERNIGHT BUT NOT INCLUDED YET AS IT IS MORE LIKELY AFTER
06Z.
E/SE WINDS AROUND 10 KNOTS BECOMING S/SE LATER THIS MORNING AT
12-18 KNOTS WITH GUSTS AROUND 25 KNOTS. S/SE WINDS OVERNIGHT AT
10-15 KNOTS.
.OUTLOOK...
FRI/FRI NGT...MVFR RESTRICTIONS POSSIBLE BY AFTERNOON IN SHRA-
TSRA.
SAT THROUGH MON...VFR UNDER HIGH PRESSURE.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...JAB
SHORT TERM...JAB
LONG TERM...CMG/RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS RALEIGH NC
945 AM EDT THU APR 18 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED OFF THE NEW ENGLAND COAST WILL EXTEND DOWN
THE EAST COAST TODAY. A STRONG COLD FRONT WILL APPROACH FROM THE
WEST TONIGHT... AND CROSS THE REGION FRIDAY AFTERNOON THROUGH FRIDAY
NIGHT. COOL HIGH PRESSURE WILL BUILD IN FROM THE WEST ON SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 945 AM THURSDAY...
TODAY:
A WEAKENING MID-LEVEL SHORTWAVE UNDER THE WEST SIDE OF THE BROAD
UPPER RIDGE WILL CONTINUE TO LIFT NORTHEAST TODAY. AS OF MID MORNING
CENTRAL NORTH CAROLINA WAS UNDER A SURFACE THETA-E MINIMUM...AND
WHILE THE 12Z KGSO SOUNDING SHOWED A VERY MOIST LAYER BETWEEN ABOUT
900MB AND 650MB WITH THE LAPSE RATE GREATER THAN MOIST ADIABATIC...
DURING THE DAY BOTH THE GFS AND THE NAM FORECAST WARMING AND DRYING
IN THAT LAYER. THIS SHOULD BE ENOUGH TO CAP THE ATMOSPHERE TO DEEP
CONVECTION. THE RUC...GFS...AND THE NAM ALL SHOW NO QPF IN CENTRAL
NORTH CAROLINA THIS AFTERNOON...AND THE HRRR WRF...ASIDE FROM WHAT
APPEAR TO BE SOME SPOTTY CU...SEEMS ALSO TO BE VERY LIMITED WITH
DEEP CONVECTION. WILL KEEP CHANCES FOR PRECIPITATION BELOW SLIGHT
CHANCE THROUGH THE AFTERNOON...AND WITH THE SHORTWAVE THERE WILL BE
AREAS OF CLOUDS THAT SHOULD GRADUALLY MIX AND BECOME INCREASINGLY
SCATTERED WITH TIME. UNDER AN OVERALL PARTLY SUNNY SKY...1000-850MB
THICKNESSES SUPPORT MAXES FROM AROUND 80 TO THE LOWER 80S...IN
CONCERT WITH MOS GUIDANCE. MIXING SHOULD PROVIDE FOR SOME WIND GUSTS
IN THE UPPER TEENS KNOTS AND A FEW LOWER 20S KNOTS AT TIMES
PARTICULARLY FROM AROUND NOON THROUGH THE MIDDLE OF THE AFTERNOON.
-DJF
TONIGHT:
STRENGTHENING SOUTHERLY MOISTURE TRANSPORT WITH THE APPROACH OF THE
AMPLIFIED UPPER TROUGH AND ATTENDANT SURFACE COLD FRONT INTO THE TN
VALLEY WILL LIKELY SUPPORT WIDESPREAD LOW CLOUDS INTO THE AREA
AFTER MIDNIGHT WITH SPOTTY WAA SHOWERS OVERSPREADING THE AREA FROM
OFF THE ATLANTIC/SOUTHEAST COAST. LOWS IN THE LOWER 60S. -CBL
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 250 AM THURSDAY...
A DEAMPLIFYING UPPER TROUGH WILL CONTINUE TO MOVE EAST THROUGHOUT
THE DAY ON FRIDAY...WITH THE PARENT SURFACE LOW MOVING WELL NORTH OF
THE AREA ACROSS THE GREAT LAKES/CANADA. THE TRAILING COLD FRONT WILL
CROSS OUR AREA FRIDAY/FRIDAY NIGHT WITH AN ACCOMPANYING LINE OF
SHOWERS AND THUNDERSTORMS. WITH THE BEST FORCING MOVING NORTH OF THE
REGION...THE MAIN CONCERN CONTINUES TO BE THE POTENTIAL FOR SEVERE
WEATHER. MODELS ARE IN GOOD AGREEMENT WITH THE LINE OF SHOWERS AND
THUNDERSTORMS MOVING ACROSS CENTRAL NC FROM WEST TO EAST FRIDAY
AFTERNOON THROUGH EARLY SATURDAY MORNING. AS IS COMMONLY THE
CASE...PLENTY OF SHEAR WILL BE IN PLACE...AS WELL AS DECENT LOW
LEVEL LAPSE RATES AS TEMPS ARE EXPECTED TO RISE INTO THE UPPER
70S/LOWER 80S...BUT THE AMOUNT OF INSTABILITY WILL BE THE MAIN
LIMITING FACTOR. MODELS CONTINUE TO PROG ONLY MARGINAL
INSTABILITY...LIKELY DUE TO THE EXTENSIVE CLOUD COVER EXPECTED AHEAD
OF THE APPROACHING FRONT...AS WELL AS THE SOMEWHAT NOCTURNAL TIMING
OF THE PRECIP (THIS SECOND POINT WILL MOSTLY COME INTO PLAY FOR THE
EASTERN PORTIONS OF THE FORECAST AREA). THE SPC DECIDED NOT TO
UPGRADE THE AREA TO A DAY 2 SLIGHT RISK FOR NOW...MAINLY DUE TO
POTENTIAL OF LIMITED INSTABILITY... ALTHOUGH THEY POINTED OUT THAT
IF ENOUGH DESTABILIZATION DOES OCCUR...A SLIGHT RISK MAY EVENTUALLY
BE NEEDED. NEVERTHELESS...WILL CONTINUE TO MENTION THE POSSIBILITY
OF STRONG TO SEVERE STORMS...WITH THE PRIMARY THREAT BEING DAMAGING
WIND...IN THE HWO. PRECIP IS EXPECTED TO COME TO AN END FROM WEST TO
EAST SATURDAY MORNING...WITH HIGH PRESSURE BUILDING IN FOR SATURDAY
NIGHT.
HIGHS ON FRIDAY ARE EXPECTED TO RANGE FROM THE UPPER 70S ACROSS THE
WEST TO LOW/MID 80S FURTHER EAST. OVERNIGHT LOWS ON FRIDAY NIGHT
WILL BE DEPENDENT ON THE TIMING OF THE EXITING PRECIP AND
COMMENCEMENT OF COLD AIR ADVECTION. AT THIS TIME...IT APPEARS PRECIP
SHOULD CLEAR OUT OF AT LEAST THE WESTERN PORTIONS OF THE FORECAST
AREA BEFORE DAYBREAK AND THEREFORE AM EXPECTING TEMPS TO RANGE FROM
THE UPPER 40S/LOWER 50S ACROSS THE WEST TO MID/UPPER 50S FURTHER
EAST. CONDITIONS WILL IMPROVE THROUGHOUT THE DAY ON SATURDAY AND
WITH COLD AIR ADVECTION PERSISTING...HIGHS SHOULD GENERALLY BE IN
THE MID/UPPER 60S. OVERNIGHT LOWS ARE EXPECTED TO FALL INTO THE 40S
AREAWIDE SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 320 AM THURSDAY...
COOL AND DRY CONDITIONS TO CLOSE THE WEEKEND AS A BROAD LONG WAVE
TROUGH WILL ENCOMPASS MUCH OF THE CONUS WITH A STRONG MIGRATORY
CANADIAN SURFACE HIGH BUILDING OVER THE NE US AND MID-ATLANTIC
REGION BEFORE QUICKLY SHIFTING OFF THE NEW ENGLAND COAST.
A BIT OF UNCERTAINTY BEGINS TO CREEP INTO THE PICTURE OWING TO
NORTHERN STREAM AMPLIFICATION OVER THE ROCKIES AND INTO THE CENTRAL
US EARLY NEXT WEEK. IN RESPONSE TO THE DIGGING TROUGH...MODELS SHOW
WEAK CYCLOGENESIS ALONG THE STALLED BAROCLINIC FRONTAL ZONE OFF THE
SOUTHEAST COAST WITH A POTENTIAL FOR ANOTHER HYBRID CAD EVENT EITHER
MONDAY OR TUESDAY PENDING THE EVOLUTION OF THE SYSTEM(STRENGTH AND
LOCATION OF THE COASTAL WAVE). THIS SCENARIO WOULD ONLY ENHANCE THE
PERIOD OF BELOW NORMAL TEMPERATURES WITH THE POTENTIAL FOR THE RAIN
AND ASSOCIATED WET BULB COOLING TO KEEP DAYTIME HIGHS IN THE LOWER
50S IF THE WETTER SOLUTIONS VERIFY. HAVE PLENTY TIME TO SIT AND WAIT
FOR MODEL DIFFERENCES TO IRON THEMSELVES OUT BEFORE FORECASTING SUCH
A DRASTIC CHANGE...BUT THE POTENTIAL IS DEFINITELY THERE GIVEN SUCH
A STRONG 1040MB CANADIAN SURFACE HIGH OFF THE NEW ENGLAND COAST. THE
LINGERING WEDGE PATTERN LEFT BEHIND WILL ATTEMPT TO ERODE BEFORE
THE AFOREMENTIONED TROUGH AND ATTENDANT SFC COLD FRONT APPROACH THE
AREA FROM THE WEST ON WEDNESDAY/THURSDAY BRINGING WIDESPREAD SHOWERS
AND POSSIBLY THE THREAT OF STORMS.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
AS OF 945 AM THURSDAY...
SOME LOW CLOUDS...MAINLY MVFR...WILL GRADUALLY INCREASE TO VFR
CONDITIONS AND A 10 TO 15KT SOUTHERLY BREEZE FOR THE AFTERNOON.
WIDESPREAD IFR TO LIFT STRATUS/LOW CLOUDS IS EXPECTED TO DEVELOP
LATE TONIGHT/EARLY FRIDAY MORNING IN THE STRENGTHENING SOUTHERLY
MOIST ADVECTION AHEAD OF THE APPROACHING COLD FRONT.
LOOKING AHEAD: ADVERSE AVIATION CONDITIONS ARE EXPECTED FRIDAY
AFTERNOON THROUGH FRIDAY NIGHT AS A LINE OF STRONG TO POSSIBLY
SEVERE STORMS CROSS THE AREA. VFR CONDITIONS IN ASSOCIATION WITH
COOL DRY HIGH PRESSURE WILL DOMINATE THE WEEKEND. WHILE THERE IS
STILL SOME UNCERTAINTY WITH RESPECT TO THE STRENGTH AND PROXIMITY
TO THE COAST...A COASTAL TROUGH/LOW COULD BRING RESTRICTIONS
IN WIDESPREAD MONDAY-TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GIH
NEAR TERM...DJF/CBL
SHORT TERM...KRR
LONG TERM...CBL
AVIATION...DJF/CBL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1255 AM CDT THU APR 18 2013
.UPDATE...
ISSUED AT 1255 AM CDT THU APR 18 2013
SNOW BAND CONTINUED ACROSS EASTERN SOUTH DAKOTA INTO SOUTHEASTERN
NORTH DAKOTA...WITH REGIONAL RADARS INDICATING DEVELOPMENT IN THE
ASHLEY AREA FOR THE PAST COUPLE OF HOURS. VISIBILITIES IN OAKES
HAD RANGED FROM 1.75 TO 3 MILES IN LIGHT SNOW FOR THE PAST 3
HOURS. KEPT HIGH POPS FOR EASTERN DICKEY AND LAMOURE COUNTIES AND
KEPT THE CHANCE MENTION IN THE WEST NEAR ASHLEY AND EDGELEY AND
JAMESTOWN. THIS SURGE OF UPPER LEVEL ENERGY WANES TOWARDS
DAYBREAK...BUT MODELS CONTINUE TO SHOW ANOTHER WAVE OF ENERGY
MOVING NORTHWARD BETWEEN SUNRISE AND NOON. KEPT CHANCE MENTION
THERE FOR THE MORNING...BUT PRECIP SHOULD DISSIPATE/MOVE EAST
SLOWLY DURING THE LATE MORNING. GIVEN PROLONGED PERIOD OF LIGHT
SNOW THAT WAS IN THE OAKES AP OBSERVATIONS...SEE NO REASON TO
CHANGE WHAT APPEARS TO BE A VALID SNOWFALL FORECAST. THUS A 2-4 INCH
SNOWFALL IN A 36 HOUR PERIOD IN DICKEY/LAMOURE SHOULD COME TO AN
END BY NOON. CURRENT FORECAST ON TRACK.
UPDATE ISSUED AT 902 PM CDT WED APR 17 2013
SNOW BAND LINING UP ACROSS THE FAR SOUTHEAST AND FAR SOUTH CENTRAL
PORTION OF THE STATE FOR THIS EVENING INTO THE EARLY MORNING.
RAISED SNOW TO DEFINITE ACROSS DICKEY...MCINTOSH...AND LAMOURE
COUNTIES AS WELL AS SOUTHEAST EMMONS. VISIBILITIES IN SNOW DOWN TO
3/4 MILE FROM PHILLIP TO MOBRIDGE EARLIER THIS EVENING AND THIS
BAND WILL MOVE NORTHEAST INTO NORTH DAKOTA. RADARS DO SHOW SOME
DECREASE IN COVERAGE/INTENSITY AND THE LATEST RUC IMPLIED THIS
SNOW WILL DIMINISH LATER TONIGHT...SO SNOWFALL IN 2 INCH RANGE
THERE LOOKS OK. REMAINDER OF STATE LOOKS GOOD. CLOUDS MOVING BACK
INTO MINOT...BUT CLEARING NORTHWEST.
UPDATE ISSUED AT 646 PM CDT WED APR 17 2013
CLEARING SKIES POKING INTO THE NORTHWEST AND NORTH CENTRAL THIS
EVENING. BANDS OF HIGH CLOUDS STRETCH SOUTHWEST THROUGH NORTHEAST
AND WILL OVER RUN SOME OF THE CLEARING AREAS SOUTH OF MINOT.
ACROSS THE SOUTHEAST...LIGHT SNOW WILL CONTINUE ACROSS DICKEY...
LAMOURE AND MCINTOSH COUNTIES THROUGH THIS EVENING. MADE SOME
ADJUSTMENTS TO CLOUDS NORTH CENTRAL AND NORTHWEST.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 340 PM CDT WED APR 17 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CONTINUING
CHANCES FOR LIGHT SNOW ACROSS THE SOUTHERN JAMES RIVER VALLEY NOW
THROUGH TONIGHT AND INTO THURSDAY.
CURRENTLY...A DYNAMIC UPPER LEVEL LONG WAVE TROUGH WAS OVER THE
ROCKIES WITH SOUTHWEST FLOW ALOFT OVER THE NORTHERN PLAINS.
MULTIPLE EMBEDDED SHORTWAVES IN THE FLOW WERE MOVING NORTHEAST
FROM THE BASE OF THE TROUGH ACROSS THE SOUTHERN ROCKIES INTO THE
CENTRAL AND NORTHERN PLAINS. AN UPPER LEVEL JET EXTENDS FROM THE
BASE OF THE TROUGH TO CENTRAL SOUTH DAKOTA INTO NORTHERN
MINNESOTA...PROVIDING THE FOCUS AREA FOR A PERSISTENT BAND OF
LIGHT TO MODERATE SNOW OVER MY SOUTHEAST SINCE EARLIER THIS
MORNING TILL NOW. WHILE SOME ACCUMULATIONS ARE OCCURRING...THIS IS
MAINLY ON GRASSY AREAS WITH ROAD SURFACES WET THANKS TO ROAD
SURFACE TEMPERATURES AT 60F OR HIGHER.
DUE IN PART TO OUR RECENT SNOWFALL...HIGH BOUNDARY LAYER MOISTURE
REMAINS ACROSS THE LOCAL REGION RESULTING IN A PERSISTENT STRATUS
DECK STILL IN PLACE OVER MOST OF WEST AND CENTRAL NORTH DAKOTA. DO
NOT SEE THIS DISSIPATING UNTIL MAYBE TOMORROW MORNING/AFTERNOON
WHEN A S/WV RIDGE MOVES INTO THE STATE HELPING TO SCOUR OUT THE
LOW CLOUDS.
WILL CONTINUE WITH THE SPS THROUGH THIS EVENING WITH SOME
ADDITIONAL LIGHT ACCUMULATIONS POSSIBLE SOUTHEAST WITH BOTH THE
NAM AND RAP BRINGING ANOTHER S/WV NORTHEAST ACROSS PORTIONS OF THE
JAMES BASIN THIS EVENING. ALREADY SEE THIS ENHANCED AREA OF
PRECIP EAST OF THE BLACK HILLS AND WEST OF PIERRE ADVECTING
NORTHEAST. WITH NIGHTFALL...ROAD SURFACE TEMPERATURES...AS THEY
DID LAST NIGHT...WILL FALL TO AROUND FREEZING...SO ICY CONDITIONS
ARE POSSIBLE AND WILL MENTION THIS WITHIN THE SPS.
SNOW CHANCES DECREASE THURSDAY MORNING/AFTERNOON ACROSS THE
SOUTHEAST AS THE UPPER JET MIGRATES EAST AND WEAK HIGH PRESSURE
BUILDS IN ACROSS CENTRAL NORTH DAKOTA. WITH THE CLOUDS SCOURING
OUT AND WITH THE S/WV RIDGE PROVIDING SOME WAA...HAVE FORECAST
HIGHS THURSDAY NEAR 40 WEST. 30S CENTRAL AND EAST WITH A MODERATE
NORTH FLOW REMAINING IN PLACE ALONG WITH A LONGER DURATION OF
CLOUDS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 340 PM CDT WED APR 17 2013
NO SIGNIFICANT STORMS IN THE LONG TERM PERIOD...HOWEVER EXPECT AN
ACTIVE PERIOD THROUGH SUNDAY AS PERIODIC CHANCES FOR SNOW/SLEET/RAIN
OCCURS ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THIS WILL RESULT IN
A COUPLE OF INCHES OF MORE SNOW TO ACCUMULATE ESPECIALLY OVER NORTH
CENTRAL NORTH DAKOTA THROUGH SUNDAY. H5 PATTERN FOR MID TO LATE NEXT
WEEK STILL IN GOOD AGREEMENT WITH ESTABLISHING A H5 RIDGE OVER THE
NORTHERN ROCKIES WITH A GRADUAL MODERATING TREND AS DENOTED IN THE
H85 TEMPERATURES ACROSS MONTANA INTO WESTERN AND CENTRAL NORTH
DAKOTA.
BEGINNING THURSDAY NIGHT...A WEAK ALBERTA CLIPPER SYSTEM SLIDES INTO
NORTHWEST NORTH DAKOTA THURSDAY NIGHT AND INTO SOUTH CENTRAL NORTH
DAKOTA 12Z FRIDAY. SHORT RANGE MODELS SHOW A BAND OF LIGHT SNOW OR
POSSIBLY A WINTRY MIX ORIENTED NORTHWEST TO SOUTHEAST WITH UP TO
ONE INCH OF SNOW IN NORTH CENTRAL NORTH DAKOTA...FROM BOWBELLS TO
STANLEY...EAST TO MINOT AND SHERWOOD. PERHAPS A DUSTING COULD OCCUR
ELSEWHERE IN CENTRAL NORTH DAKOTA. LINGERING LIGHT SNOW CONTINUES
INTO FRIDAY MORNING WITH THE LOW EXITING FRIDAY AFTERNOON. EXPECT A
BRIEF PERIOD OF DRY WEATHER FRIDAY AFTERNOON INTO A PORTION OF
FRIDAY NIGHT.
FRIDAY NIGHT/SATURDAY/SUNDAY...SURFACE LOW PRESSURE/WARM FRONT IN
EASTERN MONTANA WILL PROGRESS EAST...RESULTING IN DECENT ISENTROPIC
ASCENT ON THE 285K-295K PRESSURE SURFACES. THIS PRODUCES HIGH
CHC/LIKELY POPS BY LATE FRIDAY NIGHT WEST...AND SPREADING INTO
CENTRAL NORTH DAKOTA SATURDAY. WARMER TEMPERATURES ALOFT WILL RESULT
IN RAIN ACROSS SOUTHWEST NORTH DAKOTA SATURDAY...WITH LIGHT SNOW
ELSEWHERE. WIDESPREAD SNOWFALL ACCUMULATIONS OF UP TO ONE INCH WILL
BE COMMON...WITH A COUPLE OF INCHES FAVORING NORTH CENTRAL NORTH
DAKOTA. ABOVE FREEZING ROAD TEMPERATURES DURING THE DAYLIGHT HOURS
SHOULD ALLOW FOR MELTING...WITH SNOWFALL ACCUMULATIONS MAINLY ON THE
GRASSY AREAS.
FOR MONDAY...A NORTHERN STREAM UPPER LOW/TROUGH FOLLOWS...AND DIGS
INTO WESTERN NORTH DAKOTA WITH A PRECIPITATION THREAT REMAINING
WEST...SOUTH...AND EAST OF THE FORECAST AREA. THIS LOW EJECTS OUT
LATE TUESDAY WITH A BUILDING H5 RIDGE DEVELOPING ALONG THE WEST
COAST. THIS RIDGE SLOWLY SIDES EAST INTO THE NORTHERN ROCKIES
WEDNESDAY THROUGH FRIDAY WITH A GRADUAL WARMUP. ABOVE AVERAGE
TEMPERATURES LIKELY IN THE WEST BY LATE NEXT WEEK. THIS SHOULD ALSO
PROMOTE A GENTLE MELT OF THE SNOWPACK UNDER A DRY WEATHER REGIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1255 AM CDT THU APR 18 2013
PLENTY OF LOW LEVEL MOISTURE FROM MELTING SNOW...AS WELL AS FROM
THE WRAP AROUND MOISTURE ASSOCIATED WITH THE LARGE STORM SYSTEM
AFFECTING THE PLAINS TO THE GREAT LAKES. EXPECT VFR TO BECOME MVFR
DURING THE NIGHTTIME HOURS...AS EXPECT FOG DEVELOPMENT IN THE CLEARING
AREA IN THE NORTHWEST PART OF THE STATE AND THE ASSOCIATED LOW
LEVEL MOISTURE FROM THE STORM SYSTEM MOVING INTO THE STATE FROM
THE SOUTHEAST. EXPECT VFR CONDITIONS TO RETURN TO TAF SITES FROM
16Z-21Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...NH
LONG TERM...KS
AVIATION...JV
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
627 AM EDT THU APR 18 2013
.SYNOPSIS...
AN ENERGETIC LOW PRESSURE SYSTEM WILL MOVE NORTHEAST THROUGH THE MID
MISSISSIPPI VALLEY TODAY...LIFTING A WARM FRONT NORTH OF THE
REGION...AND ALLOWING FOR VERY WARM CONDITIONS ACROSS THE OHIO
VALLEY. AS THE LOW ENTERS THE GREAT LAKES EARLY FRIDAY...THE
TRAILING COLD FRONT WILL SWING THROUGH WITH A LINE OF PRECIPITATION
AND GUSTY WINDS. HIGH PRESSURE WILL SETTLE INTO THE OHIO VALLEY FOR
THE WEEKEND...BRINGING MUCH COOLER BUT DRY WEATHER.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DEVELOPING SURFACE LOW PRESSURE IS CURRENTLY LOCATED OVER
MISSOURI...AND WILL BEGIN A NORTHEASTWARD TREK TOWARD THE SOUTHERN
GREAT LAKES REGION TODAY. AS AN IMPRESSIVE FEED OF MOISTURE SETS
UP ACROSS THE MISSISSIPPI VALLEY...AND THE SURFACE LOW SPLITS INTO
TWO AND REFOCUSES NEAR CHICAGO BY EVENING...THE ILN CWA WILL BE
FAR ENOUGH FROM THE ACTION TO PROVIDE A MOSTLY DRY FORECAST. THE
CWA WILL BE FIRMLY IN THE WARM SECTOR OF THIS WEATHER
SYSTEM...WITH STRONG SSW FLOW PROVIDING WARM ADVECTION AT ALL
LEVELS. BETWEEN THE WARM AIR MOVING IN ALOFT...AND THE DISTANCE
FROM THE SURFACE BOUNDARIES...DEVELOPMENTAL CONVECTION OVER THE
ILN CWA APPEARS UNLIKELY. A MAJORITY OF THE MODELS DO ALLOW FOR
SOME WEAK DEVELOPMENT ACROSS EASTERN OHIO...WHERE SURFACE T/TD
WILL BE A BIT HIGHER...PERHAPS JUST ENOUGH TO WEAKLY BREAK THE CAP
WITH DISORGANIZED CONVECTION. VERY LITTLE JUSTIFICATION FOR MORE
THAN 20-POPS IN CENTRAL OHIO BECAUSE OF THIS...GIVEN AN ALMOST
COMPLETE LACK OF SUPPORT FOR ORGANIZED LIFT.
OF GREATER CONCERN IS AN INDICATION FROM RECENT HRRR RUNS / THE
06Z NAM12 / THE 00Z SPC-WRF...WHICH DEPICT A PROGRESSIVE MCS
MOVING OUT OF MISSOURI/ILLINOIS THIS MORNING AND HEADING ENE INTO
THE NW ILN CWA BY AFTERNOON. THIS SCENARIO IS NOT SUPPORTED BY THE
ENTIRE MODEL SUITE...AND IN FACT...WAS A LATE ADDITION EVEN TO
THIS DISCUSSION. ALTHOUGH THE WIND FLOW BELOW 500MB IS GENERALLY
SOUTH-SOUTHWESTERLY...WHICH WOULD NOT SUPPORT SUCH A MOTION...THIS
MAY BE A SITUATION WHERE CONVECTION DEVELOPS AND PROPAGATES TOWARD
INSTABILITY ALONG THE NORTHERN GRADIENT. INSTABILITY WILL
CERTAINLY BUILD OVER INDIANA AND OHIO BY AFTERNOON...MEANING THAT
THIS SCENARIO WILL HAVE TO BE MONITORED CLOSELY.
ANOTHER ISSUE FOR TODAY IS SIMPLY THE STRENGTH OF THE SSW
FLOW...WHICH WILL BE REALIZED A BIT AT THE SURFACE THANKS TO
FAVORABLE MIXING (AT OR ABOVE 850MB). THERE IS WIDESPREAD MODEL
AGREEMENT IN 850MB WINDS EXCEEDING 40 KNOTS THIS AFTERNOON IN THE
NORTHWESTERN PORTION OF THE CWA...WITH VALUES NEAR 30 KNOTS ALL
THE WAY TO THE SOUTHEASTERN CWA. THIS IS IN RESPONSE TO THE
DEEPENING SURFACE/850MB LOW TO THE NORTHWEST...WHICH ALLOWS FOR A
PRESSURE GRADIENT THAT ONLY GETS PROGRESSIVELY MORE TIGHT THROUGH
THE DAY. USING BUFKIT MIXING AS A GUIDE...GUSTS SHOULD EASILY
REACH 25-30 KNOTS IN THE SOUTHEASTERN CWA...WITH 30-35 KNOT VALUES
NEAR AND NORTH/WEST OF THE INTERSTATE 71 CORRIDOR. THERE WAS SOME
DISCUSSION ON THE POSSIBILITY OF ADVISORY-CRITERIA CONDITIONS IN
THE WESTERN HALF OF THE CWA. THIS LOOKS UNLIKELY TO OCCUR IN THE
CINCINNATI AREA...BUT FOR DAYTON/RICHMOND ON NORTH...IT WOULD NOT
BE SURPRISING TO SEE A FEW GUSTS IN THE 35-40 KNOT RANGE. NOT
QUITE ENOUGH FOR A HEADLINE...BUT EASILY WORTH SPS/HWO MENTIONS.
MAX TEMPS WILL BE HIGHEST IN THE SOUTHEAST...WHERE CLOUDS WILL BE
LESS OF AN IMPACT...AND THE MAGNITUDE OF THE ADVECTION IS A LITTLE
STRONGER. 80S ARE IN THE GRIDS FOR MOST OF THE CWA (MID-80S IN THE
SOUTHEAST)...ROUGHLY 15 DEGREES ABOVE NORMAL. RECORD HIGHS AT THE
BIG THREE (87 CVG / 88 CMH / 89 DAY) ARE LIKELY SAFE FROM THE
FORECAST VALUES TODAY (83 CVG / 82 CMH / 81 DAY).
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE OVERALL LARGE-SCALE MODEL AGREEMENT FOR THE IMPENDING COLD
FRONTAL PASSAGE REMAINS VERY STRONG. AS THIS SYSTEM IS NOW IN THE
RANGE OF SEVERAL MESOSCALE MODEL RUNS...THE FINER DETAILS THAT ARE
NOW BEING RESOLVED RAISE SEVERAL QUESTIONS INTO THE OTHERWISE
WELL-HANDLED FORECAST.
AN AREA OF LOW PRESSURE (THE SOUTHWESTERN OF THE TWO FROM THE
SPLIT) WILL BE LOCATED NEAR CHICAGO AT 00Z...MOVING NORTHEAST
TOWARD THE STRAITS OF MACKINAC BY 12Z FRIDAY MORNING. A STRONG
COLD FRONT IS EASILY EVIDENT ON JUST ABOUT ANY MODEL FIELD OF
CHOICE (MSLP...THETA-E...SURFACE-BASED LI...WINDS...ET CETERA). A
DEEPENING UPPER TROUGH WILL BE MOVING ENE THROUGH THE NORTHERN
MISSISSIPPI VALLEY...WITH AN ALREADY TIGHT HEIGHT PATTERN BECOMING
EVEN MORE SO BY FRIDAY MORNING. THIS DYNAMIC SETUP WILL ALLOW FOR
A LARGE AMOUNT OF WIND ENERGY TO BE PRESENT OVER THE OHIO
VALLEY...LEADING THE PRIMARY SEVERE QUESTION INTO THAT OF
INSTABILITY AND TIMING.
AS MENTIONED IN THE NEAR TERM...A FEW MODELS INDICATE ACTIVITY
SNEAKING INTO THE CWA WELL AHEAD OF THE FRONTAL PASSAGE.
RAP13/NAM12 DATA SEEMS TO DEVELOP QUITE A BIT OF CONVECTION AHEAD
OF THE SHARP FRONTAL BOUNDARY...GENERALLY OVER INDIANA BUT ALSO
A BIT INTO OHIO. ON THE HIGH-RESOLUTION RUNS...SIMULATED
REFLECTIVITY INDICATES CONVECTIVE ELEMENTS (BOWS AND LINE
SEGMENTS) THAT ATTAIN A BIT MORE OF A SW-TO-NE DIRECTION OF
MOVEMENT (AS OPPOSED TO THE LARGE-SCALE FLOW THROUGH THE FRONTAL
REGION...WHICH IS SSW-TO-NNE). THIS IS IN CONTRAST TO SOME OTHER
MODELS (SUCH AS THE CMC REGIONAL / ECMWF) WHICH KEEP PRECIPITATION
LIMITED VERY STRICTLY TO THE FRONTAL BOUNDARY AND BEHIND. EVEN IF
CONVECTION DOES NOT OCCUR AHEAD OF THE FRONT...ONE KEY THAT CAN BE
PICKED UP FROM THESE HIGHER-RESOLUTION RUNS IS THAT THE NATURE OF
THE FRONT EDGE OF THE CONVECTION WILL NOT LIKELY BE AS ONE
STRAIGHT LINE. RATHER...THE STRUCTURE MAY BE MORE
COMPLICATED...AND ANALYSIS OF THE MESOSCALE PARAMETERS DOES
SUPPORT A QLCS SCENARIO WITH EMBEDDED WAVES IN THE PATTERN.
AS IS OFTEN THE CASE IN THESE SCENARIOS...THE 0-6KM SHEAR IS
STRONG (50-60 KNOTS) BUT IT IS THE 0-1KM SHEAR THAT REALLY STICKS
OUT AS IMPRESSIVE (ALSO 40-50 KNOTS). HODOGRAPHS IN THIS LAYER
SHOW A NICE CURVE FROM SOUTHERLY TO UP TO 60 KNOTS OF
SOUTHWESTERLY FLOW AT ABOUT 3000 FEET AGL. THE OBVIOUS TAKEAWAY
FROM THESE PARAMETERS IS THAT THEY ARE QUITE FAVORABLE FOR STRONG
WINDS AND EVEN TORNADO DEVELOPMENT. HOWEVER...THE BOUNDARY LAYER
INSTABILITY WILL BE THE QUESTION AS FOR WHETHER OR NOT THIS
KINETIC ENERGY CAN BE REALIZED. FEW MODELS (IF ANY) SHOW MORE THAN
A COUPLE HUNDRED J/KG OF LEGITIMATE SURFACE BASED CAPE BY THE TIME
THE FRONT IS ENTERING THE ILN CWA...AND EVEN THIS DISSIPATES WITH
TIME AS THE FRONT CROSSES WEST TO EAST. HOWEVER...AT THE TIME OF
THE ARRIVAL OF THE FRONT...MODEL SOUNDINGS INDICATE A THERMAL
PROFILE THAT IS ROUGHLY MOIST ADIABATIC. THERE ARE NO SIGNS OF A
LEGITIMATE TEMPERATURE INVERSION DEVELOPING BEFORE THE FRONT ARRIVES.
SPC HAS ISSUED A RELATIVELY LARGE MODERATE RISK TODAY...EXTENDING
FROM MICHIGAN TO MISSISSIPPI. THIS AREA CAPTURES THE LOCATION OF
THE FRONT AND ITS CONVECTION AT A MORE FAVORABLE DIURNAL TIME
PERIOD. WHILE THIS IS CLEARLY THE AREA MORE FAVORED FOR A
SIGNIFICANT SEVERE THREAT...THE THREAT IS EXPECTED TO CONTINUE
INTO THE ILN CWA AS THE FRONT ARRIVES NEAR MIDNIGHT. THOUGH THE
GRADUAL TREND WILL BE TOWARD A WEAKENING SYSTEM (WITH THUNDER
BECOMING QUESTIONABLE LATER IN THE OVERNIGHT)...THE ELEMENTS
APPEAR TO BE IN PLACE FOR A QLCS CAPABLE OF DAMAGING WIND AND
MESOVORTICIES. THESE SEVERE WEATHER THREATS WILL BE GREATEST IN
THE WESTERN HALF OF THE CWA...WHERE THE SPC SLIGHT RISK IS
INDICATED...BUT MAY BE PRESENT EVEN THROUGH THE EAST.
IN TERMS OF THE OTHER ELEMENTS OF THE FORECAST...
POPS...AN ATTEMPT WAS MADE TO TIME OUT THE FRONT WITH AN AREA OF
100-POPS...AND KEEP THE GRADIENTS AS SHARP AS POSSIBLE ON EITHER
SIDE. HOWEVER...SOME POPS HAD TO BE INCLUDED AHEAD OF THE FRONT TO
ACCOUNT FOR A POSSIBILITY OF PROGRESSIVE ELEMENTS OR WARM SECTOR
CONVECTION (THOUGH ADMITTEDLY...THE LATTER WILL BECOME RATHER
UNLIKELY AFTER SUNSET). ON FRIDAY...SOME POPS WERE INCLUDED IN THE
NORTH AS THE BACK-END OF THE UPPER TROUGH MOVES THROUGH THE GREAT
LAKES...BUT THIS IS UNLIKELY TO RESULT IN ANYTHING MORE THAN SOME
LIGHT RAIN SHOWERS.
TEMPS...NON-DIURNAL THROUGH THURSDAY NIGHT AND FRIDAY...WITH THE
FRONTAL PASSAGE ALMOST COMPLETELY DOMINATING THE DIURNAL COMPONENT
OF THE TEMPERATURE CURVE. MAX TEMPS FOR FRIDAY WILL BE JUST BEHIND
THE FRONT...WITH COLD ADVECTION THROUGH THE DAY KEEPING TEMPS FROM
RISING.
RAINFALL...A GENERAL MODEL CONSENSUS PROVIDES FOR RAINFALL AMOUNTS
OF AROUND AN INCH IN THE WESTERN CWA...AND SLIGHTLY HIGHER THAN A
HALF INCH IN THE EASTERN CWA. ALTHOUGH GROUND CONDITIONS ARE A BIT
ON THE WET SIDE...THESE VALUES DO NOT SEEM TO BE ENOUGH TO PROMOTE
A FLOODING THREAT...ESPECIALLY CONSIDERING THE PROGRESSIVE NATURE
OF THIS FRONTAL SYSTEM. OHRFC MMEFS GUIDANCE DOES NOT INDICATE
MUCH OF A CHANCE FOR ANY ILN RIVER POINTS TO ENTER FLOOD OR EVEN
ACTION STAGE. SOUTH-SOUTHWESTERLY MOISTURE TRANSPORT AHEAD OF THE
FRONT IS IMPRESSIVE...AND IT WOULD NOT BE SURPRISING IF A FEW
CONVECTIVE ELEMENTS LED TO LOCALIZED HIGHER VALUES THAN THE
MENTIONED FORECAST. SO...ISOLATED/LOCALIZED FLOODING COULD BE
POSSIBLE...BUT LIKELY ONLY OF THE SHORT-TERM VARIETY.
WINDS...ASIDE FROM THE SEVERE THREAT...STRONG WINDS ARE EXPECTED
IN THE COLD ADVECTION (WSW FLOW) BEHIND THE COLD FRONT. THIS
PATTERN SUPPORTS MIXING AS THE BOUNDARY LAYER COOLS RATHER
DEEPLY...AND GUSTS IN THE NORTH MAY APPROACH ADVISORY CRITERIA.
FINALLY...THE MUCH COLDER AIR MASS WILL PRESENT THE POSSIBILITY OF
FROST ON FRIDAY AND SATURDAY NIGHTS...ESPECIALLY SATURDAY NIGHT
(WITH CLEARER SKIES).
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MODELS ARE IN A WIDE RANGE FOR TIMING FOR THE TUESDAY/WEDNESDAY
SYSTEM. THE PREVIOUS FORECAST APPEARS TO HAVE THE BEST INITIAL
CONDITIONS BUT SOME NEIGHBORING OFFICES APPEAR HIGHER THAN I AM
WILLING TO GO WITH RAIN CHANCES OVERNIGHT TUESDAY. GIVEN THE
LATEST EUROPEAN WHICH SPINS THE SYSTEM UP IN THE MIDWEST ON
TUESDAY...IT HAS A MUCH SLOWER AND MORE DEVELOPED SYSTEM THAN THE
GFS WHICH IS INDICATING AN OPEN WAVE YET STRONG COLD FRONTAL
PASSAGE EARLY WEDNESDAY. WPC HAS THIS FRONT ON THE OTHER SIDE OF
THE APPALACHIANS AT THIS TIME WHICH APPEARS INCONSISTENT WITH THE
REST OF THE GUIDANCE I SEE.
UNTIL THE RAIN HITS WITH THE NEXT SYSTEM DAYS 6/7...TEMPERATURES
WILL BE ON THE INCREASE AND START FROM A COOLER 50S ON SATURDAY WITH
OVERNIGHT LOWS LIKELY NEEDING FROST HEADLINES. BY THIS TIME NEXT
WEEK AHEAD OF THE COLD FRONT...70S WILL BE FOUND AGAIN WITH
OVERNIGHT LOWS IN THE 50S. HAVE GONE WARMER THAN GUIDANCE AHEAD OF
THE NEXT SYSTEM BUT FEEL THAT THE FORECAST WILL CONTINUE TO BE
ADJUSTED UPWARD A LITTLE BIT EACH DAY.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
POTENT UPPER LEVEL TROUGH WILL MOVE INTO THE PLAINS TODAY. AS IT
DOES...SURFACE LOW PRESSURE WILL DEEPEN OVER THE MID MISSISSIPPI
RIVER VALLEY. FOR THE MOST PART...THE AREA SHOULD BE MAINLY WARM
SECTORED WITH A CHANCE OF A POP UP SHOWER OR STORM IN THE AFTERNOON.
SOME OF THE HIGHER RESOLUTION...CONVECTIVE ALLOWING
MODELS...HOWEVER...ARE SUGGESTING THAT SOME CONVECTIVE LINE
SEGMENTS MOVING ACROSS ILLINOIS INTO INDIANA THIS MORNING MAY PUSH
INTO EAST CENTRAL INDIANA AND WEST CENTRAL OHIO THIS AFTERNOON.
THIS WOULD BRING AN INCREASE RISK FOR THUNDERSTORMS AT THE KDAY
TAF. HAVE PLACED A VCTS/CB IN KDAY FOR THE AFTERNOON HOURS. RADAR
AND MODEL TRENDS WILL HAVE TO BE WATCHED TO SEE IF THIS SCENARIO
MATERIALIZES. AS THE SURFACE LOW DEEPENS AND DAYTIME MIXING KICKS
IN...SOUTHERLY WINDS WILL INCREASE AND WILL BE GUSTY BETWEEN 30
AND 35 KNOTS.
FOR TONIGHT...ANY AFTERNOON CONVECTION LOOKS TO WANE UNTIL A
STRONG COLD FRONT ARRIVES BETWEEN 06Z AND 12Z. AS IT DOES...A LINE
OF SHOWERS AND EMBEDDED THUNDERSTORMS ARE EXPECTED ALONG THE COLD
FRONT...FOLLOWED BY A PERIOD OF MODERATE TO LOCALLY HEAVY RAIN
SHOWERS. THIS WILL RESULT IN CONDITIONS DROPPING INTO THE MVFR
CATEGORY ALONG WITH SOME IFR VISIBILITIES IN THE HEAVIER RAIN.
ALSO...WINDS WILL CONTINUE GUSTY AND SHIFT TO THE WEST WITH FROPA.
WINDS WILL BE LOCALLY HIGHER IN AND NEAR THUNDERSTORMS. AT THIS
TIME,..IT APPEARS INSTABILITY WILL BE WEAKENING AS THE FRONT
PUSHES TOWARD THE KCMH/KLCK TAF SITES TOWARD 12Z BUT HAVE DECIDED
TO LEAVE A VCTS IN THESE TERMINALS AS WELL.
OUTLOOK...MVFR CONDITIONS WITH LOCAL IFR VISIBILITIES EXPECTED IN
SHOWERS FRIDAY MORNING. WEST WINDS GUSTING BETWEEN 30 AND 35 KNOT
ON FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...FRANKS
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
450 AM EDT THU APR 18 2013
.SYNOPSIS...
AN ENERGETIC LOW PRESSURE SYSTEM WILL MOVE NORTHEAST THROUGH THE MID
MISSISSIPPI VALLEY TODAY...LIFTING A WARM FRONT NORTH OF THE
REGION...AND ALLOWING FOR VERY WARM CONDITIONS ACROSS THE OHIO
VALLEY. AS THE LOW ENTERS THE GREAT LAKES EARLY FRIDAY...THE
TRAILING COLD FRONT WILL SWING THROUGH WITH A LINE OF PRECIPITATION
AND GUSTY WINDS. HIGH PRESSURE WILL SETTLE INTO THE OHIO VALLEY FOR
THE WEEKEND...BRINGING MUCH COOLER BUT DRY WEATHER.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DEVELOPING SURFACE LOW PRESSURE IS CURRENTLY LOCATED OVER
MISSOURI...AND WILL BEGIN A NORTHEASTWARD TREK TOWARD THE SOUTHERN
GREAT LAKES REGION TODAY. AS AN IMPRESSIVE FEED OF MOISTURE SETS
UP ACROSS THE MISSISSIPPI VALLEY...AND THE SURFACE LOW SPLITS INTO
TWO AND REFOCUSES NEAR CHICAGO BY EVENING...THE ILN CWA WILL BE
FAR ENOUGH FROM THE ACTION TO PROVIDE A MOSTLY DRY FORECAST. THE
CWA WILL BE FIRMLY IN THE WARM SECTOR OF THIS WEATHER
SYSTEM...WITH STRONG SSW FLOW PROVIDING WARM ADVECTION AT ALL
LEVELS. BETWEEN THE WARM AIR MOVING IN ALOFT...AND THE DISTANCE
FROM THE SURFACE BOUNDARIES...DEVELOPMENTAL CONVECTION OVER THE
ILN CWA APPEARS UNLIKELY. A MAJORITY OF THE MODELS DO ALLOW FOR
SOME WEAK DEVELOPMENT ACROSS EASTERN OHIO...WHERE SURFACE T/TD
WILL BE A BIT HIGHER...PERHAPS JUST ENOUGH TO WEAKLY BREAK THE CAP
WITH DISORGANIZED CONVECTION. VERY LITTLE JUSTIFICATION FOR MORE
THAN 20-POPS IN CENTRAL OHIO BECAUSE OF THIS...GIVEN AN ALMOST
COMPLETE LACK OF SUPPORT FOR ORGANIZED LIFT.
OF GREATER CONCERN IS AN INDICATION FROM RECENT HRRR RUNS / THE
06Z NAM12 / THE 00Z SPC-WRF...WHICH DEPICT A PROGRESSIVE MCS
MOVING OUT OF MISSOURI/ILLINOIS THIS MORNING AND HEADING ENE INTO
THE NW ILN CWA BY AFTERNOON. THIS SCENARIO IS NOT SUPPORTED BY THE
ENTIRE MODEL SUITE...AND IN FACT...WAS A LATE ADDITION EVEN TO
THIS DISCUSSION. ALTHOUGH THE WIND FLOW BELOW 500MB IS GENERALLY
SOUTH-SOUTHWESTERLY...WHICH WOULD NOT SUPPORT SUCH A MOTION...THIS
MAY BE A SITUATION WHERE CONVECTION DEVELOPS AND PROPAGATES TOWARD
INSTABILITY ALONG THE NORTHERN GRADIENT. INSTABILITY WILL
CERTAINLY BUILD OVER INDIANA AND OHIO BY AFTERNOON...MEANING THAT
THIS SCENARIO WILL HAVE TO BE MONITORED CLOSELY.
ANOTHER ISSUE FOR TODAY IS SIMPLY THE STRENGTH OF THE SSW
FLOW...WHICH WILL BE REALIZED A BIT AT THE SURFACE THANKS TO
FAVORABLE MIXING (AT OR ABOVE 850MB). THERE IS WIDESPREAD MODEL
AGREEMENT IN 850MB WINDS EXCEEDING 40 KNOTS THIS AFTERNOON IN THE
NORTHWESTERN PORTION OF THE CWA...WITH VALUES NEAR 30 KNOTS ALL
THE WAY TO THE SOUTHEASTERN CWA. THIS IS IN RESPONSE TO THE
DEEPENING SURFACE/850MB LOW TO THE NORTHWEST...WHICH ALLOWS FOR A
PRESSURE GRADIENT THAT ONLY GETS PROGRESSIVELY MORE TIGHT THROUGH
THE DAY. USING BUFKIT MIXING AS A GUIDE...GUSTS SHOULD EASILY
REACH 25-30 KNOTS IN THE SOUTHEASTERN CWA...WITH 30-35 KNOT VALUES
NEAR AND NORTH/WEST OF THE INTERSTATE 71 CORRIDOR. THERE WAS SOME
DISCUSSION ON THE POSSIBILITY OF ADVISORY-CRITERIA CONDITIONS IN
THE WESTERN HALF OF THE CWA. THIS LOOKS UNLIKELY TO OCCUR IN THE
CINCINNATI AREA...BUT FOR DAYTON/RICHMOND ON NORTH...IT WOULD NOT
BE SURPRISING TO SEE A FEW GUSTS IN THE 35-40 KNOT RANGE. NOT
QUITE ENOUGH FOR A HEADLINE...BUT EASILY WORTH SPS/HWO MENTIONS.
MAX TEMPS WILL BE HIGHEST IN THE SOUTHEAST...WHERE CLOUDS WILL BE
LESS OF AN IMPACT...AND THE MAGNITUDE OF THE ADVECTION IS A LITTLE
STRONGER. 80S ARE IN THE GRIDS FOR MOST OF THE CWA (MID-80S IN THE
SOUTHEAST)...ROUGHLY 15 DEGREES ABOVE NORMAL. RECORD HIGHS AT THE
BIG THREE (87 CVG / 88 CMH / 89 DAY) ARE LIKELY SAFE FROM THE
FORECAST VALUES TODAY (83 CVG / 82 CMH / 81 DAY).
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE OVERALL LARGE-SCALE MODEL AGREEMENT FOR THE IMPENDING COLD
FRONTAL PASSAGE REMAINS VERY STRONG. AS THIS SYSTEM IS NOW IN THE
RANGE OF SEVERAL MESOSCALE MODEL RUNS...THE FINER DETAILS THAT ARE
NOW BEING RESOLVED RAISE SEVERAL QUESTIONS INTO THE OTHERWISE
WELL-HANDLED FORECAST.
AN AREA OF LOW PRESSURE (THE SOUTHWESTERN OF THE TWO FROM THE
SPLIT) WILL BE LOCATED NEAR CHICAGO AT 00Z...MOVING NORTHEAST
TOWARD THE STRAITS OF MACKINAC BY 12Z FRIDAY MORNING. A STRONG
COLD FRONT IS EASILY EVIDENT ON JUST ABOUT ANY MODEL FIELD OF
CHOICE (MSLP...THETA-E...SURFACE-BASED LI...WINDS...ET CETERA). A
DEEPENING UPPER TROUGH WILL BE MOVING ENE THROUGH THE NORTHERN
MISSISSIPPI VALLEY...WITH AN ALREADY TIGHT HEIGHT PATTERN BECOMING
EVEN MORE SO BY FRIDAY MORNING. THIS DYNAMIC SETUP WILL ALLOW FOR
A LARGE AMOUNT OF WIND ENERGY TO BE PRESENT OVER THE OHIO
VALLEY...LEADING THE PRIMARY SEVERE QUESTION INTO THAT OF
INSTABILITY AND TIMING.
AS MENTIONED IN THE NEAR TERM...A FEW MODELS INDICATE ACTIVITY
SNEAKING INTO THE CWA WELL AHEAD OF THE FRONTAL PASSAGE.
RAP13/NAM12 DATA SEEMS TO DEVELOP QUITE A BIT OF CONVECTION AHEAD
OF THE SHARP FRONTAL BOUNDARY...GENERALLY OVER INDIANA BUT ALSO
A BIT INTO OHIO. ON THE HIGH-RESOLUTION RUNS...SIMULATED
REFLECTIVITY INDICATES CONVECTIVE ELEMENTS (BOWS AND LINE
SEGMENTS) THAT ATTAIN A BIT MORE OF A SW-TO-NE DIRECTION OF
MOVEMENT (AS OPPOSED TO THE LARGE-SCALE FLOW THROUGH THE FRONTAL
REGION...WHICH IS SSW-TO-NNE). THIS IS IN CONTRAST TO SOME OTHER
MODELS (SUCH AS THE CMC REGIONAL / ECMWF) WHICH KEEP PRECIPITATION
LIMITED VERY STRICTLY TO THE FRONTAL BOUNDARY AND BEHIND. EVEN IF
CONVECTION DOES NOT OCCUR AHEAD OF THE FRONT...ONE KEY THAT CAN BE
PICKED UP FROM THESE HIGHER-RESOLUTION RUNS IS THAT THE NATURE OF
THE FRONT EDGE OF THE CONVECTION WILL NOT LIKELY BE AS ONE
STRAIGHT LINE. RATHER...THE STRUCTURE MAY BE MORE
COMPLICATED...AND ANALYSIS OF THE MESOSCALE PARAMETERS DOES
SUPPORT A QLCS SCENARIO WITH EMBEDDED WAVES IN THE PATTERN.
AS IS OFTEN THE CASE IN THESE SCENARIOS...THE 0-6KM SHEAR IS
STRONG (50-60 KNOTS) BUT IT IS THE 0-1KM SHEAR THAT REALLY STICKS
OUT AS IMPRESSIVE (ALSO 40-50 KNOTS). HODOGRAPHS IN THIS LAYER
SHOW A NICE CURVE FROM SOUTHERLY TO UP TO 60 KNOTS OF
SOUTHWESTERLY FLOW AT ABOUT 3000 FEET AGL. THE OBVIOUS TAKEAWAY
FROM THESE PARAMETERS IS THAT THEY ARE QUITE FAVORABLE FOR STRONG
WINDS AND EVEN TORNADO DEVELOPMENT. HOWEVER...THE BOUNDARY LAYER
INSTABILITY WILL BE THE QUESTION AS FOR WHETHER OR NOT THIS
KINETIC ENERGY CAN BE REALIZED. FEW MODELS (IF ANY) SHOW MORE THAN
A COUPLE HUNDRED J/KG OF LEGITIMATE SURFACE BASED CAPE BY THE TIME
THE FRONT IS ENTERING THE ILN CWA...AND EVEN THIS DISSIPATES WITH
TIME AS THE FRONT CROSSES WEST TO EAST. HOWEVER...AT THE TIME OF
THE ARRIVAL OF THE FRONT...MODEL SOUNDINGS INDICATE A THERMAL
PROFILE THAT IS ROUGHLY MOIST ADIABATIC. THERE ARE NO SIGNS OF A
LEGITIMATE TEMPERATURE INVERSION DEVELOPING BEFORE THE FRONT ARRIVES.
SPC HAS ISSUED A RELATIVELY LARGE MODERATE RISK TODAY...EXTENDING
FROM MICHIGAN TO MISSISSIPPI. THIS AREA CAPTURES THE LOCATION OF
THE FRONT AND ITS CONVECTION AT A MORE FAVORABLE DIURNAL TIME
PERIOD. WHILE THIS IS CLEARLY THE AREA MORE FAVORED FOR A
SIGNIFICANT SEVERE THREAT...THE THREAT IS EXPECTED TO CONTINUE
INTO THE ILN CWA AS THE FRONT ARRIVES NEAR MIDNIGHT. THOUGH THE
GRADUAL TREND WILL BE TOWARD A WEAKENING SYSTEM (WITH THUNDER
BECOMING QUESTIONABLE LATER IN THE OVERNIGHT)...THE ELEMENTS
APPEAR TO BE IN PLACE FOR A QLCS CAPABLE OF DAMAGING WIND AND
MESOVORTICIES. THESE SEVERE WEATHER THREATS WILL BE GREATEST IN
THE WESTERN HALF OF THE CWA...WHERE THE SPC SLIGHT RISK IS
INDICATED...BUT MAY BE PRESENT EVEN THROUGH THE EAST.
IN TERMS OF THE OTHER ELEMENTS OF THE FORECAST...
POPS...AN ATTEMPT WAS MADE TO TIME OUT THE FRONT WITH AN AREA OF
100-POPS...AND KEEP THE GRADIENTS AS SHARP AS POSSIBLE ON EITHER
SIDE. HOWEVER...SOME POPS HAD TO BE INCLUDED AHEAD OF THE FRONT TO
ACCOUNT FOR A POSSIBILITY OF PROGRESSIVE ELEMENTS OR WARM SECTOR
CONVECTION (THOUGH ADMITTEDLY...THE LATTER WILL BECOME RATHER
UNLIKELY AFTER SUNSET). ON FRIDAY...SOME POPS WERE INCLUDED IN THE
NORTH AS THE BACK-END OF THE UPPER TROUGH MOVES THROUGH THE GREAT
LAKES...BUT THIS IS UNLIKELY TO RESULT IN ANYTHING MORE THAN SOME
LIGHT RAIN SHOWERS.
TEMPS...NON-DIURNAL THROUGH THURSDAY NIGHT AND FRIDAY...WITH THE
FRONTAL PASSAGE ALMOST COMPLETELY DOMINATING THE DIURNAL COMPONENT
OF THE TEMPERATURE CURVE. MAX TEMPS FOR FRIDAY WILL BE JUST BEHIND
THE FRONT...WITH COLD ADVECTION THROUGH THE DAY KEEPING TEMPS FROM
RISING.
RAINFALL...A GENERAL MODEL CONSENSUS PROVIDES FOR RAINFALL AMOUNTS
OF AROUND AN INCH IN THE WESTERN CWA...AND SLIGHTLY HIGHER THAN A
HALF INCH IN THE EASTERN CWA. ALTHOUGH GROUND CONDITIONS ARE A BIT
ON THE WET SIDE...THESE VALUES DO NOT SEEM TO BE ENOUGH TO PROMOTE
A FLOODING THREAT...ESPECIALLY CONSIDERING THE PROGRESSIVE NATURE
OF THIS FRONTAL SYSTEM. OHRFC MMEFS GUIDANCE DOES NOT INDICATE
MUCH OF A CHANCE FOR ANY ILN RIVER POINTS TO ENTER FLOOD OR EVEN
ACTION STAGE. SOUTH-SOUTHWESTERLY MOISTURE TRANSPORT AHEAD OF THE
FRONT IS IMPRESSIVE...AND IT WOULD NOT BE SURPRISING IF A FEW
CONVECTIVE ELEMENTS LED TO LOCALIZED HIGHER VALUES THAN THE
MENTIONED FORECAST. SO...ISOLATED/LOCALIZED FLOODING COULD BE
POSSIBLE...BUT LIKELY ONLY OF THE SHORT-TERM VARIETY.
WINDS...ASIDE FROM THE SEVERE THREAT...STRONG WINDS ARE EXPECTED
IN THE COLD ADVECTION (WSW FLOW) BEHIND THE COLD FRONT. THIS
PATTERN SUPPORTS MIXING AS THE BOUNDARY LAYER COOLS RATHER
DEEPLY...AND GUSTS IN THE NORTH MAY APPROACH ADVISORY CRITERIA.
FINALLY...THE MUCH COLDER AIR MASS WILL PRESENT THE POSSIBILITY OF
FROST ON FRIDAY AND SATURDAY NIGHTS...ESPECIALLY SATURDAY NIGHT
(WITH CLEARER SKIES).
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MODELS ARE IN A WIDE RANGE FOR TIMING FOR THE TUESDAY/WEDNESDAY
SYSTEM. THE PREVIOUS FORECAST APPEARS TO HAVE THE BEST INITIAL
CONDITIONS BUT SOME NEIGHBORING OFFICES APPEAR HIGHER THAN I AM
WILLING TO GO WITH RAIN CHANCES OVERNIGHT TUESDAY. GIVEN THE
LATEST EUROPEAN WHICH SPINS THE SYSTEM UP IN THE MIDWEST ON
TUESDAY...IT HAS A MUCH SLOWER AND MORE DEVELOPED SYSTEM THAN THE
GFS WHICH IS INDICATING AN OPEN WAVE YET STRONG COLD FRONTAL
PASSAGE EARLY WEDNESDAY. WPC HAS THIS FRONT ON THE OTHER SIDE OF
THE APPALACHIANS AT THIS TIME WHICH APPEARS INCONSISTENT WITH THE
REST OF THE GUIDANCE I SEE.
UNTIL THE RAIN HITS WITH THE NEXT SYSTEM DAYS 6/7...TEMPERATURES
WILL BE ON THE INCREASE AND START FROM A COOLER 50S ON SATURDAY WITH
OVERNIGHT LOWS LIKELY NEEDING FROST HEADLINES. BY THIS TIME NEXT
WEEK AHEAD OF THE COLD FRONT...70S WILL BE FOUND AGAIN WITH
OVERNIGHT LOWS IN THE 50S. HAVE GONE WARMER THAN GUIDANCE AHEAD OF
THE NEXT SYSTEM BUT FEEL THAT THE FORECAST WILL CONTINUE TO BE
ADJUSTED UPWARD A LITTLE BIT EACH DAY.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
A WARM FRONT WILL CONTINUE TO MOVE NORTH TOWARD THE GREAT LAKES
REGION THIS MORNING. POTENT UPPER LEVEL TROUGH WILL MOVE INTO THE
PLAINS TODAY. AS IT DOES...SURFACE LOW PRESSURE WILL DEEPEN AS IT
MOVE NE FROM THE SOUTHERN PLAINS TO THE UPPER MISSISSIPPI RIVER
VALLEY. OUR AREA WILL BE MAINLY WARM SECTORED TODAY WITH A MIX OF
DIURNAL CUMULUS AND HIGH LEVEL CLOUDS. THERE IS STILL A SMALL
CHANCE OF A POP UP SHOWER OR STORM IN THE WARM SECTOR...BUT THIS
IS NOT HIGH ENOUGH TO MENTION IN THE TAFS. AS THE SURFACE LOW
DEEPENS AND DAYTIME MIXING KICKS IN...SOUTHERLY WINDS WILL
INCREASE AND WILL BE GUSTY BETWEEN 30 AND 35 KNOTS.
FOR TONIGHT...DEEPENING LOW PRESSURE WILL MOVE FROM THE UPPER
MISSISSIPPI RIVER VALLEY TO THE U.P. OF MICHIGAN. A DYNAMIC COLD
FRONT IS FORECAST TO PUSH EAST INTO THE REGION BETWEEN 06Z AND
12Z. AS IT DOES...A LINE OF SHOWERS AND EMBEDDED THUNDERSTORMS ARE
EXPECTED ALONG THE COLD FRONT...FOLLOWED BY A PERIOD OF MODERATE
TO LOCALLY HEAVY RAIN SHOWERS. THIS WILL RESULT IN CONDITIONS
DROPPING INTO THE MVFR CATEGORY ALONG WITH SOME IFR VISIBILITIES
IN THE HEAVIER RAIN. ALSO...WINDS WILL CONTINUE GUSTY AND SHIFT TO
THE WEST WITH FROPA. WINDS WILL BE LOCALLY HIGHER IN AND NEAR
THUNDERSTORMS. ATTM...IT APPEARS INSTABILITY WILL BE WEAKENING AS
THE FRONT PUSHES TOWARD THE KCMH/KLCK TAF SITES TOWARD 12Z SO NOT
MUCH THUNDER MAY BE LEFT BY THE TIME IT REACHES THESE TERMINALS.
OUTLOOK...MVFR CONDITIONS WITH LOCAL IFR VISIBILITIES EXPECTED IN
SHOWERS FRIDAY MORNING. WEST WINDS GUSTING TO 30 KT EXPECTED
FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...FRANKS
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
425 AM CDT THU APR 18 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 420 AM CDT THU APR 18 2013
UPPER LEVEL SUPPORT RAPIDLY EXPANDING NORTHWARD THIS MORNING AND
WILL MAXIMIZE OVER SOUTHEAST SOUTH DAKOTA INTO NORTHWEST IOWA BY
ABOUT 18Z TODAY. INSTABILITY FROM ABOUT 850MB TO 700MB OVER
SOUTHEAST NEBRASKA INTO WESTERN IOWA ALLOWING CONVECTIVE ELEMENTS TO
DEVELOP IN THOSE AREAS BUT THE INSTABILITY NOT REAL IMPRESSIVE SO
NOT THINKING THAT IT WILL PLAY A HUGE ROLE IN THE WEATHER OVER THE
NEXT 24 HOURS. DO EXPECT SOME INCREASED RAINFALL RATES IN NORTHWEST
IOWA HOWEVER AND THE MAIN CONCERN WILL BE A RIBBON OF FREEZING
PRECIPITATION AND SLEET FROM SIOUX CITY TOWARDS SHELDON INTO PARTS
OF SOUTHWEST MINNESOTA THROUGH ABOUT LATE MORNING. FARTHER WEST IT
SHOULD BE MAINLY SNOW AND A BAND OF HEAVY SNOWFALL STILL LOOKS GOOD
FROM YANKTON TO SIOUX FALLS INTO SOUTHWEST MINNESOTA. UPPER LEVEL PV
ADVECTION MAXIMIZES THIS MORNING AND THE 750MB TO 650MB FRONT IS
PLANTED RIGHT OVER SOUTHEAST SOUTH DAKOTA INTO SOUTHWEST MINNESOTA.
WHILE THERE IS SOME INSTABILITY ABOVE THE FRONT IT IS NOT NEARLY AS
IMPRESSIVE AS LAST WEEKS SYSTEM. SO AT THIS TIME NOT PLANNING ON ANY
THUNDER SNOW BUT SNOWFALL RATES OF AN INCH AN HOUR AT TIMES STILL
LIKELY. THE BEST CHANCE FOR THE HEAVIEST SNOWFALL RATES WILL BE FROM
ABOUT 12Z THROUGH 19Z SHIFTING FROM FROM SOUTH TO NORTH. STILL
EXPECT SNOW TO CONTINUE THROUGH THE REMAINDER OF THE AFTERNOON AND
EVENING...DECREASING PRETTY QUICKLY FOR THE WEST TONIGHT.
THE 21Z SREF HAS PRETTY GOOD CLUSTERING AROUND 8 TENTHS OF AN INCH
OF LIQUID AROUND SIOUX FALLS WHILE THE LATEST GEM/ECMWF/NAM ARE
CLOSER TO 6 TO 7 TENTHS OF LIQUID. THE 3Z SREF HAS DROPPED OFF QUITE
A BIT WITH STORM TOTAL LIQUID AFTER 12Z THIS MORNING ABOUT
0.45...THIS TAKING AWAY THE 0.13 IT HAD IN BEFORE 12Z WHICH DOES NOT
LOOK LIKE IT WILL OCCUR. IN FACT MOST AREAS WEST OF A YANKTON TO
SLAYTON LINE LIKELY WILL GET ONLY A COUPLE OF TENTHS OR LESS
THROUGH 12Z THIS MORNING WITH MAYBE AN INCH OR SO FROM THE JAMES
VALLEY WEST. TAKING THIS INTO ACCOUNT WITH ALL OF THE MODELS LOOKS
LIKE WE WILL SETTLE IN TO MORE OF A 4 TO 6 TENTHS LIQUID
POTENTIAL. GIVEN SOME COMPACTION AND MELTING AS IT FALLS 4 TO 6
INCHES SEEMS ABOUT RIGHT FOR THE SIOUX FALLS AREA WITH AN INCH OR
TWO MORE IN SOUTHWEST MINNESOTA. A LITTLE WORRIED THAT THE
SNOWFALL FALLING DURING THE DAY VERSUS AT NIGHT LIKE LAST WEEK AND
LESS INSTABILITY THAN THAT SYSTEM AS WELL AS SURFACE TEMPERATURES
ABOUT 2-3 DEGREES WARMER WILL KEEP AMOUNTS ABOUT 4-5 INCHES.
LATEST RUNS OF THE HRRR AS WELL AS THE RAP KEEP THE BETTER AMOUNTS
JUST EAST AND NORTH OF THE INTERSTATE 29 CORRIDOR WHICH MATCHES
FAIRLY WELL WITH THE MID LEVEL BOUNDARY...AROUND 700MB AND THE
EDGE OF THE DRY SLOT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 420 AM CDT THU APR 18 2013
FRIDAY AND SATURDAY WILL CONTINUE TO SEE BELOW NORMAL TEMPERATURES
ESPECIALLY WITH THE SNOW COVER. ANOTHER SYSTEM WILL BRING THE
CHANCE FOR RAIN OR SNOW TO THE AREA SATURDAY AND SATURDAY NIGHT
BUT IS NOT EXPECTED TO BE A MAJOR IMPACT.
THE SUNDAY INTO MIDDLE OF NEXT WEEK PERIOD IS CHARACTERIZED BY
CONTINUED BELOW NORMAL TEMPERATURES WITH TROUGHING OVER THE CENTRAL
US. SUNDAY COULD ACTUALLY BE ONE OF THE WARMER DAYS WITH HIGHS
GETTING INTO THE 50S OVER PORTIONS OF THE AREA. STAYED ON THE COOLER
SIDE OF GUIDANCE FOR NOW...WITH THE THOUGHT THAT AT LEAST SOME SNOW
COVER REMAINS OVER A GOOD PORTION OF THE CWA. BUT IF SNOW IS MAINLY
GONE...SUNDAY COULD BE SEVERAL DEGREES WARMER THAN CURRENTLY
FORECAST. AS THE THE LONGWAVE TROUGH BUILDS IN...OUR AREA WILL SEE
MULTIPLE SHORTWAVES TRAVERSE THE AREA. THUS THE THE THREAT OF RAIN
SHOWERS CONTINUE SUNDAY INTO SUNDAY NIGHT. NOT LOOKING AT A LOT OF
QPF...BUT MOST PLACES SHOULD GET SOMETHING. COLD FRONT MOVES THROUGH
MONDAY INTO MONDAY NIGHT. WITH THE MID LEVEL FRONT THE THREAT OF
RAIN SHOWERS WILL CONTINUE. THERMAL PROFILES GET COLD ENOUGH THAT WE
COULD SEE SOME SNOW MIX IN LATER MONDAY INTO MONDAY NIGHT...BUT AT
THIS TIME WITH THE WAVE MORE PROGRESSIVE...DOES NOT LOOK LIKE WE SEE
MUCH IN THE WAY OF ANY ACCUMULATING SNOW...BUT WILL HAVE TO MONITOR
MODEL TRENDS. THE SYSTEM MOVES EAST ON TUESDAY...WHICH SHOULD LEAD
TO A MAINLY DRY COUPLE DAYS...ALTHOUGH HIGHS WILL BE STUCK IN THE
40S ON TUESDAY WITH THE TROUGH OVERHEAD. A SLOW WARMING TREND SHOULD
BEGIN BY WEDNESDAY...WITH HIGHS GETTING INTO THE UPPER 40S TO MID
50S. LONGER RANGE GUIDANCE CONTINUES TO SUGGEST A WARMING TREND
LATER NEXT WEEK INTO THE WEEKEND...WITH ACTUAL SPRING LIKE WEATHER
POSSIBLY FINALLY ARRIVING.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 629 PM CDT WED APR 17 2013
DETERIORATING CONDITIONS THROUGH THE NIGHT AS MIXED PRECIPITATION
OVERSPREADS THE AREA. MAY HAVE SOME ISOLATED THUNDERSTORM ACTIVITY
OVER NORTHWESTERN IOWA EARLY IN THE EVENING...OTHERWISE
PRECIPITATION THAT DEVELOPS WILL BE MAINLY IN THE FORM OF SNOW
THROUGH THE JAMES RIVER VALLEY...WITH A BAND OF MIXED
PRECIPITATION EAST OF THIS AREA...THEN ALL RAIN THROUGH
NORTHWESTERN IOWA. AS THE NIGHT PROGRESSES...PRECIPITATION WILL
TRANSITION TO ALL SNOW FROM WEST TO EAST...WITH SNOW THEN
PERSISTING INTO THURSDAY EVENING. IN ADDITION...NORTHWESTERLY
WINDS WILL INCREASE TONIGHT AND TOMORROW...WITH GUSTS OF 35 TO 40
KTS ON THURSDAY AFTERNOON.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR SDZ038-039-050-
052>055-057>061-063>066-068>071.
WINTER STORM WARNING UNTIL 1 AM CDT FRIDAY FOR SDZ040-056-062-
067.
MN...WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR MNZ090.
WINTER STORM WARNING UNTIL 1 AM CDT FRIDAY FOR MNZ071-072-080-
081-089-097-098.
IA...WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR IAZ002-003-
012>014-020-021-031.
WINTER STORM WARNING UNTIL 1 AM CDT FRIDAY FOR IAZ001.
NE...WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR NEZ013-014.
&&
$$
SHORT TERM...08
LONG TERM...CHENARD
AVIATION...JM
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
617 AM CDT THU APR 18 2013
.UPDATE...FOR 12Z AVIATION FORECAST
.AVIATION...
STRONG LINE OF CONVECTION FROM CHICAGO DOWN THROUGH SAINT LOUIS
INTO FAR EASTERN OKLAHOMA AND EASTERN TEXAS WILL MOVE EAST TODAY
AND BE ALONG THE MISSISSIPPII RIVER BY 23Z AND ALONG THE TENNESSEE
RIVER BY 02Z AND INTERSTATE 65 AT 05Z AND ON THE PLATEAU BY 11Z.
LOW LEVEL JET OUT AHEAD OF THE LINE ON THE ORDER OF 65 TO 70 KNOTS
WILL PULL EAST WITH THE LINE TODAY AND TONIGHT. BOUNDARY LAYER
WINDS ALREADY 45 KNOTS AT BNA THIS MORNING WILL LIKELY SUSTAIN
THIS SPEED DURING THE DAY AND EVENING WITH SURFACE WINDS GUSTS TO
30 KNOTS DURING THE DAY AND INTO THE EVENING ACROSS THE MID STATE.
WILL INCLUDE LOW LEVEL WIND SHEAR FOR THIS MORNING AT ALL
TERMINALS. STRONG CAPPING INVERSION BASED AROUND 825 MBARS WILL
PRECLUDE ANY THUNDERSTORM DEVELOPMENT UNTIL TONIGHT. ONCE SQUALL
LINE PASSES TONIGHT LOOK FOR GUSTY WEST WINDS TO FOLLOW.
BOYD
&&
.PREV DISCUSSION... /ISSUED 400 AM CDT THU APR 18 2013/
..MODERATE RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO
TONIGHT...
DISCUSSION...
FEW OVERALL CHANGES TO THE FORECAST OVER THE NEXT WEEK...WITH
MAINLY SLIGHT ADJUSTMENTS TO TEMPS AND TIMING OF PRECIP. A LARGE
H5 TROUGH OVER THE PLAINS STATES WILL SHIFT INTO THE MISSISSIPPI
VALLEY TODAY THEN ACROSS THE TENNESSEE VALLEY TONIGHT...WITH AN
ASSOCIATED STRONG COLD FRONT SWEEPING THROUGH THE MID STATE
TONIGHT. BEFORE THE FRONT ARRIVES...ANOTHER SUMMER-LIKE DAY IS ON
TAP WITH TEMPERATURES STARTING OUT IN THE 60S TO AROUND 70 THIS
MORNING THEN WARMING UP INTO THE LOW TO MID 80S AREAWIDE THIS
AFTERNOON. AS A SUB-1000MB SURFACE LOW TAKES SHAPE ACROSS THE
MIDWEST...925MB WINDS WILL INCREASE ACROSS OUR REGION INTO THE
40-50KT RANGE TODAY LEADING TO GUSTY SOUTH WINDS AT THE SURFACE.
ANTICIPATING SOUTH WINDS IN THE 15 TO 30 MPH RANGE DEVELOPING LATER
THIS MORNING...THEN CONTINUING INTO THE AFTERNOON HOURS BEFORE
SUBSIDING SOMEWHAT EARLY IN THE EVENING. OCCASIONAL GUSTS TO NEAR
40 MPH APPEAR LIKELY AS WELL BASED ON BUFKIT SOUNDINGS. SOUTH
WINDS WILL INCREASE AGAIN LATER IN THE EVENING AS A SHARP PRESSURE
GRADIENT MOVES ACROSS THE MID STATE AHEAD OF THE COLD FRONT. TO
SIMPLIFY MATTERS...HAVE ISSUED A WIND ADVISORY FOR ALL ZONES
BEGINNING LATER THIS MORNING AND CONTINUING THROUGH THE EARLY
MORNING HOURS ON FRIDAY.
SPC HAS PLACED AREAS ALONG AND WEST OF THE I-65 CORRIDOR IN A
MODERATE RISK FOR SEVERE STORMS THURSDAY EVENING WITH A SLIGHT
RISK TO THE EAST THURSDAY NIGHT. 00Z GFS/NAM/ECMWF AND LATEST
HIGH RESOLUTION 4.0 KM WRF...NSSL WRF...AND HRRR ALL INDICATE A
STRONG TO SEVERE QLCS WILL FORM LATER TODAY ALONG THE
FRONT...REACHING THE TENNESSEE RIVER BY MID EVENING...I-65
CORRIDOR AROUND MIDNIGHT...AND EXIT EAST OF THE CWA NEAR/AFTER
SUNRISE FRIDAY MORNING. MODELS CONTINUE TO DEPICT GENERALLY WEAK
INSTABILITY AROUND 500 J/KG AHEAD OF THE LINE...BUT SOME GUIDANCE
INDICATES A SURGE OF MID/UPPER 60S DEWPOINTS COMING NORTHWARD
AHEAD OF THE QLCS WHICH COULD BUMP UP CAPE VALUES TO NEAR/OVER
1000 J/KG ACROSS WESTERN ZONES. REGARDLESS...IMPRESSIVE 0-3KM SRH
STRENGTHENING INTO THE 500-800 M2/S2 RANGE AND VERY LONG CURVED
HODOGRAPHS SUGGESTS A SIGNIFICANT DAMAGING WIND THREAT WITH THE
LINE OF STORMS ALONG WITH SOME QLCS TORNADOES. HIGHEST RISK OF
DAMAGING WINDS/TORNADOES IS EXPECTED TO BE ALONG/WEST OF I-65 IN
THE 02-06Z TIMEFRAME ACROSS THE MODERATE RISK AREA...AS STORMS
WILL ENCOUNTER INCREASINGLY LESS INSTABILITY AND WEAKENING SHEAR
OFF TO THE EAST.
STRATIFORM RAIN AND A FEW THUNDERSTORMS WILL CONTINUE MUCH OF THE
NIGHT BEHIND THE QLCS WITH RAINFALL COMING TO AN END FROM WEST TO
EAST FRIDAY MORNING. MUCH COOLER TEMPERATURES ARE ANTICIPATED
FRIDAY AND SATURDAY WITH LOWS FALLING INTO THE MID TO UPPER 30S
SATURDAY MORNING. WITH SURFACE RIDGE SETTLING OVER THE MID
STATE...LIGHT TO CALM WINDS...AND DEWPOINTS FALLING INTO THE 20S
AND 30S...PATCHY FROST APPEARS POSSIBLE FOR MUCH OF THE FORECAST
AREA AND HAVE ADDED MENTION TO ZONES. AREA WILL BEGIN TO WARMUP
FROM SUNDAY INTO EARLY NEXT WEEK AS SOUTHERLY FLOW BEGINS ANEW.
FEW CHANGES WERE MADE IN THE EXTENDED FORECAST WITH NEXT CHANCE
FOR RAIN AROUND TUESDAY/WEDNESDAY OF NEXT WEEK.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 10 AM THIS MORNING TO 1 AM CDT FRIDAY FOR
TNZ005>011-022>034-056>066-075-077>080-093>095.
&&
$$
01
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
630 AM CDT THU APR 18 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 336 AM CDT THU APR 18 2013
MODERATE TO HEAVY RAINFALL AND FLOODING POTENTIAL FOR PORTIONS OF
THE FORECAST AREA TODAY AND EVENTUAL CHANGE-OVER TO SNOW OVERNIGHT
REMAIN THE MAIN CONCERNS IN THE SHORT TERM.
WATER VAPOR IMAGERY/RAP 500MB ANALYSIS SHOW A DEEP TROUGH OF LOW
PRESSURE EXTENDING FROM THE DAKOTAS INTO THE 4-CORNERS AREA. DEEP
SOUTHERLY FETCH ON THE EAST SIDE OF THIS TROUGH WAS SENDING COPIOUS
MOISTURE NORTHWARD TOWARD THE AREA. AN EMBEDDED VIGOROUS SHORTWAVE
TROUGH WAS NOTED EJECTING NORTHEASTWARD OUT OF THE SOUTHERN
PLAINS...INTERACTING WITH THE MOISTURE-RICH ENVIRONMENT. THIS WAVE
WAS SPAWNING SOME EARLY MORNING SEVERE WEATHER ACROSS NORTHEAST
OK/SOUTHWEST MO. NORTHERN FRINGES OF THIS WAVE WAS PUSHING
SHOWERS/SCATTERED THUNDERSTORMS NORTHEAST ACROSS IA TOWARD SOUTHERN
PORTIONS OF THE FORECAST AREA PER THE RADAR MOSAIC. OTHERWISE...
SURFACE MAP HAS A SURFACE LOW OVER NORTHEAST OK WITH A WARM FRONT
EXTENDING NORTHEAST ACROSS CENTRAL MO INTO SOUTHERN IL. STRONG LIFT
AND MOISTURE TRANSPORT OVER THE WARM FRONT WAS ALSO PRODUCING A
VIGOROUS SW-NE LINE CONVECTION FROM WEST CENTRAL IL TO NEAR
CHICAGO...AND INTO SOUTHERN LOWER MI. OUR AREA WAS IN A TEMPORARY
PRECIPITATION LULL FOR NOW.
FOR TODAY...LOOK FOR THAT MAIN SHORTWAVE TROUGH OVER THE SOUTHERN
PLAINS TO PUSH MORE RAIN INTO THE AREA THROUGH THIS MORNING WITH
EMBEDDED THUNDERSTORMS MAINLY CONFINED MAINLY ALONG AND SOUTH OF
I-90. ONCE THAT SHORTWAVE TROUGH/MAIN AXIS OF MOISTURE TRANSPORT
MOVES EAST OF THE AREA BY LATER THIS MORNING...WILL LIKELY SEE A
DIMINISHING TREND IN THE RAIN...PERHAPS GOING OVER TO DRIZZLE.
FOR LATER INTO THIS AFTERNOON...WILL SEE DEFORMATION SHIELD RAIN
SPREADING IN FROM WEST TO EAST AS THE MAIN LONG-WAVE UPPER LEVEL
TROUGH PUSHES EAST FROM THE PLAINS TOWARD THE AREA. AS THE COLUMN
COOLS DUE TO DYNAMIC COOLING...THERE COULD BE SOME FLAKES OF SNOW
MIXING IN WEST OF THE MISSISSIPPI AFTER 5-6 PM.
THEN FOR TONIGHT...CONTINUED DYNAMIC COOLING WILL TAKE PLACE AS THE
UPPER TROUGH ROTATES ACROSS THE AREA. WITH THIS...PLAN ON A
TRANSITION FROM RAIN TO SNOW FROM WEST TO EAST. RIGHT NOW...IT
APPEARS 1 TO LOCALLY 2 INCHES OF SNOWFALL IS POSSIBLE FOR PORTIONS
OF SOUTHEAST MINNESOTA INTO NORTH CENTRAL WISCONSIN. OTHER AREAS
WILL LIKELY SEE LESS THAN A HALF INCH OF SLUSHY ACCUMULATION.
IMPACTS FROM RAINFALL INTO THIS EVENING WILL BE DISCUSSED IN THE
HYDROLOGY SECTION BELOW.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 336 AM CDT THU APR 18 2013
FRIDAY LOOKS LIKE A RAW DAY ACROSS THE FORECAST AREA AS THE TROUGH
AND ASSOCIATED DEFORMATION SNOW/RAIN AREA MOVE ACROSS THE REGION
ALONG WITH BRISK NORTHWEST WINDS IN THE 15 TO 30 MPH RANGE. PLAN ON
PERHAPS ANOTHER 1/2-1 INCH OF SLUSHY ACCUMULATION MAINLY NORTH OF
I-94. OTHERWISE...THE BRISK NORTHWEST WINDS COMBINED WITH HIGHS ONLY
IN THE MIDDLE 30S TO LOWER 40S WILL MAKE IT FEEL MORE LIKE THE UPPER
20S/LOWER 30S.
FINALLY...SOME DRIER AIR MOVES INTO THE AREA FRIDAY NIGHT THROUGH
SATURDAY AS HIGH PRESSURE TAKES CONTROL. THIS WILL BE A BRIEF
RESPITE THROUGH AS YET ANOTHER AREA OF LOW PRESSURE WILL MOVE ACROSS
THE NORTHERN PLAINS AND ACROSS THE AREA SATURDAY NIGHT THROUGH
MONDAY. ISENTROPIC LIFT AHEAD OF THE WAVE SATURDAY NIGHT WILL YIELD
A CHANCE OF RAIN AND SNOW AND ALL RAIN DURING THE DAY SUNDAY INTO
SUNDAY NIGHT. ON MONDAY...A COLD FRONT WILL PUSH SOUTHEAST INTO THE
AREA WHILE A WAVE OF LOW PRESSURE RIPPLES NORTHEAST ALONG THIS
BAROCLINIC ZONE FOR A CHANCE OF SHOWERS/THUNDER. THUNDER CHANCES
LOOK HIGHER ALONG AND SOUTH OF I-90 WHERE 0-3KM MUCAPE CLIMBS INTO
THE 500-900J/KG RANGE.
PRECIPITATION CHANCES WILL CONTINUE STRAIGHT THROUGH WEDNESDAY AS
BAROCLINICITY LINGERS ACROSS THE AREA WITH A COUPLE WAVES OF LOW
PRESSURE RIPPLING UP ALONG IT. COULD BE SOME SNOW MIXING IN DURING
THE NIGHT MONDAY NIGHT AND ESPECIALLY TUESDAY NIGHT.
OTHERWISE...BESIDES RELATIVELY MILDER DAYS ON SUNDAY MONDAY WITH
HIGHS MAINLY IN THE 50S...UNSEASONABLY COOL SPRING SO FAR WILL
CONTINUE WITH HIGHS MAINLY IN THE 40S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 630 AM CDT THU APR 18 2013
SURFACE LOW WILL LIFT NORTHEAST INTO SOUTHERN WISCONSIN THIS
AFTERNOON AND THEN TO NORTHERN LAKE MICHIGAN TONIGHT. RAIN WILL
CONTINUE AT TE TAF SITES THROUGH THE EARLY MORNING HOURS...WITH THE
18.08Z HRRR SHOWING A LULL IN THE ACTIVITY FROM MID MORNING INTO
THE AFTERNOON...WHERE ONLY DRIZZLE WILL OCCUR. HOWEVER AS RAIN
LIGHTENS UP...VISIBILITIES WILL LIKELY DROP BACK INTO THE IFR
CATEGORY. AS THE DEFORMATION BAND OF PRECIPITATION MOVES IN LATER
THIS AFTERNOON...THE RAIN WILL MIX WITH AND THEN CHANGE TO SNOW
TONIGHT. THIS CHANGEOVER LOOKS TO OCCUR AROUND 03Z AT KRST AND
BETWEEN 05Z-08Z AT KLSE. ONCE THIS OCCURS EXPECT LOWER END MVFR
CEILINGS AND IFR VISIBILITIES.
&&
.HYDROLOGY...TODAY INTO TONIGHT
ISSUED AT 336 AM CDT THU APR 18 2013
FLOOD WATCH IN EFFECT THROUGH THURSDAY NIGHT FOR PORTIONS NORTHEAST
IA INTO SOUTHWEST AND CENTRAL WI.
RAINFALL OVER THE LAST 24 HOURS RANGED FROM 1/2 INCH TO AROUND 1.5
INCHES ACROSS NORTHEAST IA INTO SOUTHWEST WI. SO FAR...SOME
SIGNIFICANT RISES NOTED ON RIVERS ACROSS THIS AREA...BUT NO FLOODING
YET. HOWEVER...WITH ANOTHER SLUG OF 1/4 TO 1/2 INCH/LOCALLY HIGHER
AMOUNTS...WILL HOLD ONTO THE FLOOD WATCH ACROSS THIS AREA FOR THE
POTENTIAL OF SOME FLOODING. RIGHT NOW...THE KICKAPOO RIVER IS OF
MOST CONCERN IF THIS ADDITIONAL RAINFALL AMOUNT IS REALIZED OVER THE
BASIN. OTHER RIVERS REMAIN HIGH WITH SOME FLOODING FROM RECENT
RAINFALL AND SNOWMELT...SUCH AS THE BLACK RIVER AND TREMPEALEAU
RIVERS. IN ADDITION...THERE WILL BE PONDING OF WATER ON ROADWAYS
ALONG WITH STANDING WATER IN LOW LYING AND POOR DRAINAGE AREAS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FLOOD WATCH THROUGH LATE TONIGHT FOR WIZ042>044-053>055-061.
MN...NONE.
IA...FLOOD WATCH THROUGH LATE TONIGHT FOR IAZ011-029-030.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...RABERDING
HYDROLOGY...DAS
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1040 AM EDT THU APR 18 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE COAST OF NOVA SCOTIA LATER TODAY,
ALLOWING A WARM FRONT TO LIFT THROUGH THE AREA THIS EVENING. A
STRONG COLD FRONT WILL MOVE THROUGH THE AREA FRIDAY NIGHT INTO
EARLY SATURDAY MORNING AS AN AREA OF LOW PRESSURE MOVES THROUGH
THE GREAT LAKES AND INTO EASTERN CANADA. HIGH PRESSURE BUILDS
ACROSS THE NORTHEAST SUNDAY INTO MONDAY. A WEAK DISTURBANCE MAY
DEVELOP OFF THE SOUTHEAST COAST AND AFFECT THE AREA LATE MONDAY
INTO TUESDAY. ANOTHER COLD FRONT IS FORECAST TO AFFECT THE AREA
LATE WEDNESDAY OR THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
TODAY...930 AM ESTF UPDATE: POPS CONTINUE TO BE BOOSTED OVER E PA AND
E MD AND NOW NEARLY 55 PCT IN SOME AREAS AS SHOWERS BECOME MORE
EVIDENT ON RADAR AND NOT TO DISAPPEAR IN THE GENERAL WAA PATTERN.
TEMPS WERE SLIGHTLY ADJUSTED THROUGH MIDDAY...BUT WITH NO CHANGE
TO THE OVERALL FCST HIGHS FROM THE MID SHIFT FCST. RAP IS THE
RUNNING A LITTLE SLOW ON THE SHOWERS. ALREADY HAVING TRACED IN
KILG AND SOON SPRINKLES IN PHL PER TDWR TPHL.
SHOWERS MOSTLY E MD AND DE THIS MORNING THRU E PA THIS AFTN AND
FOR NOW CONSIDERED SCT AT ANY ONE TIME, BUT MANY AREAS WILL TRACE
TO .01 TODAY WITH A FEW .10 POSSIBLE E PA.
BLAME IT ON A WARM FRONT...GENERAL WAA.
CONTINUE TO NOTICE A SPIKE IN RH EARLY THIS AFTN..VIA TSECS...WHICH
SIGNALS BETTER LIFT. RAP SUGGESTS TOPS TO MAYBE 17000 FT.
THE .01 TO .02/HR SHOWERS INCREASING NOW OVER E MD INTO N DEL WILL
BECOME THEIR MOST EXPANSIVE DURING THE EARLY AFTN AS THEY MOVE
THROUGH E PA AND W NJ.
FOG ADDED TO COASTAL DE AND FAR SNJ.
TONIGHT...CONSIDERABLE LOW CLOUDINESS AND A STRONGER SLY FLOW AS THE
CDFNT TO THE W ADVANCES TWD THE REGION. THERE ARE MODEL INDICATIONS
OF A DENSE FOG PROBLEM HERE AND THERE DESPITE BL WINDS OF ALMOST
20 KT. SUSPECT CIGS WILL LOWER DURING THE NIGHT WITH VSBY AT ITS
LOWEST NEAR 1 MI TOWARD DAWN FRIDAY. FOR NOW...PATCHY FOG HAS BEEN
ADDED TO THE FCST LATER TONIGHT.
&&
.SHORT TERM /FRIDAY/...
FRIDAY...EARLY IN THE DAY FOG LIFTS AS WE BECOME MORE DEFINED WITHIN
THE WARM SECTOR OF THE SYSTEM, AHEAD OF THE APPROACHING COLD FRONT.
WE EXPECT A WARM, BREEZY MIDDAY/AFTERNOON. A WEAK SHORT WAVE MAY
CROSS THE AREA VERY LATE IN THE DAY AHEAD OF THE APPROACHING COLD
FRONT WHICH COMBINED WITH SOME WEAK AFTERNOON INSTABILITY MAY
SPARK A FEW SHOWERS/THUNDERSTORMS.
THERE IS A GOOD CHANCE OF SSW GUSTS 30-40 KT ON THE NON WATER
INFLUENCED REGION OF OUR INTERIOR MID ALTC CWA 18Z-21Z FRIDAY.
THIS PER SEVERAL RUNS OF THE NAM AND WITH SOME GFS SUPPORT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
FRIDAY NIGHT...THE COLD FRONT IS FORECAST TO MOVE INTO OUR WESTERN
AREAS AROUND OR SHORTLY AFTER SUNSET AND MOVE EASTWARD THROUGH THE
NIGHT. WITH PW VALUES NEAR 1.5 INCHES, A PERIOD OF HEAVY RAIN IS
POSSIBLE. THERE IS SOME WEAK INSTABILITY AHEAD OF THE FRONT...MUCAPES
NEAR 200-300 J/KG, LI`S NEAR -1 TO -2, K-INDEX VALUES IN THE
30S...SO SOME EMBEDDED THUNDERSTORMS ARE POSSIBLE. RAINFALL
AMOUNTS WILL BE ENHANCED WHERE/IF THUNDERSTORMS DO DEVELOP. THE
GOOD NEWS IS THE FRONT IS FORECAST TO BE FAIRLY PROGRESSIVE AND
MOVE THROUGH THE AREA OVERNIGHT AND BE OFFSHORE BY SUNRISE
SATURDAY WHICH SHOULD LIMIT ANY FLOOD POTENTIAL TO THE URBAN/POOR
DRAINAGE TYPE.
SOME LINGERING LIGHT RAIN IS POSSIBLE, MAINLY TOWARD THE COAST,
EARLY SATURDAY AS THE FRONT PUSHES FARTHER AWAY FROM THE AREA.
BEHIND THE FRONT, A GUSTY WESTERLY FLOW WILL DEVELOP.
HIGH PRESSURE WILL BUILD ACROSS THE NORTHEAST SATURDAY NIGHT INTO
SUNDAY WHICH WILL PROVIDE DRY WEATHER FOR THE REGION. THE HIGH TRIES
TO RETREAT NORTHEASTWARD ON MONDAY, BUT WE MAY STILL REMAIN UNDER
THE GRASP OF THE FAR SOUTHERN EXTEND OF THE HIGH. THICKNESSES FAIL
TO RECOVER SUNDAY INTO MONDAY, AND WITH AN EASTERLY FLOW ACROSS THE
AREA TEMPERATURES ARE FORECAST TO BE A FEW DEGREES BELOW NORMAL. AS
THE HIGH RETREATS MONDAY INTO MONDAY NIGHT, A WEAK SURFACE TROUGH IS
FORECAST TO DEVELOP OFFSHORE OF THE SOUTHEAST STATES AND BEGIN
NOSING ITS WAY TOWARD OUR AREA. WITH A COUPLE OF WEAK SHORT WAVES
MOVING ACROSS THE AREA, WE COULD HAVE SOME PRECIPITATION DEVELOP AND
MOVE ACROSS THE AREA. SCATTERED SHOWERS COULD CONTINUE INTO TUESDAY
WITH A COUPLE OF WEAK SHORT WAVES EMBEDDED IN THE SOUTHWEST FLOW
ALOFT.
ANOTHER COLD FRONT IS FORECAST TO AFFECT THE AREA SOMETIME LATE
WEDNESDAY INTO THURSDAY. THIS COULD BRING ANOTHER ROUND OF MODERATE
TO HEAVY RAINFALL TO THE AREA.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...AREAS OF IFR CIGS POSSIBLY TO SPREAD INTO PHL/ILG MID OR LATE
MORNING. CIGS WILL BE AN OCNL PBLM TODAY AND CERTAINLY NOT AN ALL
VFR DAY. ESE WIND INCREASING WITH GUSTS THIS AFTN TO NEAR 20 KT.
PLEASE FOLLOW TAF ADJUSTMENTS AS THE DETERIORATING CONDITIONS
UNFOLD.
TONIGHT...IFR CIGS BECOMING WIDESPREAD WITH VSBY LOWERING TO LESS
THAN A MILE LATER AT NIGHT WITH A SMALL CHC OF LIFR CONDS IN
PATCHY DENSE FOG...ESPECIALLY E PA AND COASTAL S NJ. THIS WITH
SREF CIG VSBY PROB SUPPORT FROM THEN 09Z/18 SREF. MANY TAFS HAVE
BEEN AMENDED AROUND 14Z FOR THIS MUCH LOWER FORECAST CONDITION
LATER TONIGHT. NEW 12Z NAM IS HIGHLY SUPPORTIVE OF STRATUS
EVENTUALLY DESCENDING TO THE DECK IN LIFR CONDS OF FOG.
THE KPHL TAF HAS BEEN ADJUSTED WITH FOG LATE. 18Z TAFS WILL ATTEMPT
A MORE COMPLETE PICTURE OF ANTICIPATED IFR-LIFR CONDITIONS LATER
THU NIGHT-FRI MORNING.
FRIDAY...IFR CONDITIONS EARLY IN DRIZZLE FOG WITH POSSIBLE VFR
LATE. CHANCE OF RAIN/THUNDERSTORMS BY AFTERNOON. GUSTY SOUTH WINDS
AROUND 25-30 KNOTS POSSIBLE. LLWS POSSIBLE KACY LATE IN THE DAY.
OUTLOOK...
FRIDAY NIGHT...MVFR/IFR CONDITIONS EXPECTED WITH A PERIOD OF HEAVY
RAIN AND THUNDERSTORMS POSSIBLE.
SATURDAY...LINGERING SHOWERS AND POSSIBLE MVFR/IFR EARLY, MAINLY
TOWARD THE COAST. IMPROVING TO VFR DURING THE DAY. GUSTY WEST WINDS
20-25 KNOTS.
SATURDAY NIGHT-SUNDAY NIGHT...VFR CONDITIONS EXPECTED.
MONDAY...MOSTLY VFR, POSSIBLE NEAR MVFR WITH SHOWERS.
&&
.MARINE...
FOG HAS BEEN ADDED TO THE FCST IN THE 930 AM PACKAGE.
A WARM FRONT WILL MOVE BY TO THE N TODAY AND SELY FLOW WILL
BECOME SLY AND INCREASE WELL INTO TONIGHT. THIS WILL CAUSE SEAS TO
INCREASE AS WELL. THEREFORE, A SCA IS BEING RAISED BEGINNING AT
19/00Z. AT THIS POINT, IT IS ONLY FOR THE OCEAN, BUT MAY NEED TO
BE EXPANDED FOR AT LEAST THE LOWER PORTION OF DEL BAY, BUT
CONFIDENCE IS LOWER HERE.
OUTLOOK...
A STRONG COLD FRONT WILL MOVE ACROSS THE WATERS FRIDAY NIGHT INTO
SATURDAY. WINDS ARE EXPECTED TO INCREASE AHEAD OF THE FRONT, AND
COULD APPROACH GALE FORCE. THERE IS A STRONG FLOW ABOVE THE SURFACE,
BUT IT MAY HAVE TROUBLE MIXING DOWN IN THE SOUTHERLY FLOW. FOR NOW,
A SMALL CRAFT ADVISORY WILL BE IN EFFECT, AND WE WILL LET THE NEXT
SHIFT SEE IF A GALE WARNING WILL BE NEEDED. ADVISORY LEVELS WINDS
AND/OR SEAS WILL LIKELY CONTINUE INTO A PART OF SATURDAY. AS HIGH
PRESSURE BUILDS ACROSS THE NORTHEAST THEN OFFSHORE EARLY NEXT WEEK,
AN EASTERLY FLOW WILL DEVELOP ACROSS THE AREA. WINDS COULD CONTINUE
TO GUST NEAR ADVISORY LEVELS THROUGH MONDAY, AND SEAS COULD REMAIN
AROUND 4-5 FEET OR HIGHER WITH THE EASTERLY FETCH.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 PM EDT FRIDAY
FOR ANZ450>455.
&&
$$
SYNOPSIS...DRAG/ROBERTSON
NEAR TERM...DRAG 1039
SHORT TERM...DRAG/NIERENBERG 1039
LONG TERM...ROBERTSON
AVIATION...DRAG/ROBERTSON 1039
MARINE...DRAG/NIERENBERG/ROBERTSON
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
943 AM EDT THU APR 18 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE COAST OF NOVA SCOTIA LATER TODAY,
ALLOWING A WARM FRONT TO LIFT THROUGH THE AREA THIS EVENING. A
STRONG COLD FRONT WILL MOVE THROUGH THE AREA FRIDAY NIGHT INTO
EARLY SATURDAY MORNING AS AN AREA OF LOW PRESSURE MOVES THROUGH
THE GREAT LAKES AND INTO EASTERN CANADA. HIGH PRESSURE BUILDS
ACROSS THE NORTHEAST SUNDAY INTO MONDAY. A WEAK DISTURBANCE MAY
DEVELOP OFF THE SOUTHEAST COAST AND AFFECT THE AREA LATE MONDAY
INTO TUESDAY. ANOTHER COLD FRONT IS FORECAST TO AFFECT THE AREA
LATE WEDNESDAY OR THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
TODAY...930 AM ESTF UPDATE: POPS CONTINUE TO BE BOOSTED OVER E PA AND E MD
AND NOW NEARLY 55 PCT IN SOME AREAS AS SHOWERS BECOME MORE EVIDENT
ON RADAR AND NOT TO DISAPPEAR IN THE GENERAL WAA PATTERN. TEMPS
WERE SLIGHTLY ADJUSTED THROUGH MIDDAY...BUT WITH NO CHANGE TO THE
OVERALL FCST HIGHS FROM THE MID SHIFT FCST. RAP IS THE RUNNING A
LITTLE SLOW ON THE SHOWERS. ALREADY HAVING TRACED IN KILG AND SOON
SPRINKLES IN PHL PER TDWR TPHL.
SHOWERS MOSTLY E MD AND DE THIS MORNING THRU E PA THIS AFTN AND
FOR NOW CONSIDERED SCT AT ANY ONE TIME, BUT MANY AREAS WILL TRACE
TO .01 TODAY WITH A FEW .10 POSSIBLE E PA.
BLAME IT ON A WARM FRONT...GENERAL WAA.
CONTINUE TO NOTICE A SPIKE IN RH EARLY THIS AFTN..VIA TSECS...WHICH
SIGNALS BETTER LIFT. RAP SUGGESTS TOPS TO MAYBE 17000 FT.
THE .01 TO .02/HR SHOWERS INCREASING NOW OVER E MD INTO N DEL WILL
BECOME THEIR MOST EXPANSIVE DURING THE EARLY AFTN AS THEY MOVE
THROUGH E PA AND W NJ.
FOG ADDED TO COASTAL DE AND FAR SNJ.
TONIGHT...CONSIDERABLE LOW CLOUDINESS AND A STRONGER SLY FLOW AS THE
CDFNT TO THE W ADVANCES TWD THE REGION. THERE ARE MODEL INDICATIONS
OF A DENSE FOG PROBLEM HERE AND THERE DESPITE BL WINDS OF ALMOST
20 KT. SUSPECT CIGS WILL LOWER DURING THE NIGHT WITH VSBY AT ITS
LOWEST NEAR 1 MI TOWARD DAWN FRIDAY. FOR NOW...PATCHY FOG HAS BEEN
ADDED TO THE FCST LATER TONIGHT.
&&
.SHORT TERM /FRIDAY/...
FRIDAY...EARLY IN THE DAY FOG LIFTS AS WE BECOME MORE DEFINED WITHIN
THE WARM SECTOR OF THE SYSTEM, AHEAD OF THE APPROACHING COLD FRONT.
WE EXPECT A WARM, BREEZY MIDDAY/AFTERNOON. A WEAK SHORT WAVE MAY
CROSS THE AREA VERY LATE IN THE DAY AHEAD OF THE APPROACHING COLD
FRONT WHICH COMBINED WITH SOME WEAK AFTERNOON INSTABILITY MAY
SPARK A FEW SHOWERS/THUNDERSTORMS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
FRIDAY NIGHT...THE COLD FRONT IS FORECAST TO MOVE INTO OUR WESTERN
AREAS AROUND OR SHORTLY AFTER SUNSET AND MOVE EASTWARD THROUGH THE
NIGHT. WITH PW VALUES NEAR 1.5 INCHES, A PERIOD OF HEAVY RAIN IS
POSSIBLE. THERE IS SOME WEAK INSTABILITY AHEAD OF THE FRONT...MUCAPES
NEAR 200-300 J/KG, LI`S NEAR -1 TO -2, K-INDEX VALUES IN THE
30S...SO SOME EMBEDDED THUNDERSTORMS ARE POSSIBLE. RAINFALL
AMOUNTS WILL BE ENHANCED WHERE/IF THUNDERSTORMS DO DEVELOP. THE
GOOD NEWS IS THE FRONT IS FORECAST TO BE FAIRLY PROGRESSIVE AND
MOVE THROUGH THE AREA OVERNIGHT AND BE OFFSHORE BY SUNRISE
SATURDAY WHICH SHOULD LIMIT ANY FLOOD POTENTIAL TO THE URBAN/POOR
DRAINAGE TYPE.
SOME LINGERING LIGHT RAIN IS POSSIBLE, MAINLY TOWARD THE COAST,
EARLY SATURDAY AS THE FRONT PUSHES FARTHER AWAY FROM THE AREA.
BEHIND THE FRONT, A GUSTY WESTERLY FLOW WILL DEVELOP.
HIGH PRESSURE WILL BUILD ACROSS THE NORTHEAST SATURDAY NIGHT INTO
SUNDAY WHICH WILL PROVIDE DRY WEATHER FOR THE REGION. THE HIGH TRIES
TO RETREAT NORTHEASTWARD ON MONDAY, BUT WE MAY STILL REMAIN UNDER
THE GRASP OF THE FAR SOUTHERN EXTEND OF THE HIGH. THICKNESSES FAIL
TO RECOVER SUNDAY INTO MONDAY, AND WITH AN EASTERLY FLOW ACROSS THE
AREA TEMPERATURES ARE FORECAST TO BE A FEW DEGREES BELOW NORMAL. AS
THE HIGH RETREATS MONDAY INTO MONDAY NIGHT, A WEAK SURFACE TROUGH IS
FORECAST TO DEVELOP OFFSHORE OF THE SOUTHEAST STATES AND BEGIN
NOSING ITS WAY TOWARD OUR AREA. WITH A COUPLE OF WEAK SHORT WAVES
MOVING ACROSS THE AREA, WE COULD HAVE SOME PRECIPITATION DEVELOP AND
MOVE ACROSS THE AREA. SCATTERED SHOWERS COULD CONTINUE INTO TUESDAY
WITH A COUPLE OF WEAK SHORT WAVES EMBEDDED IN THE SOUTHWEST FLOW
ALOFT.
ANOTHER COLD FRONT IS FORECAST TO AFFECT THE AREA SOMETIME LATE
WEDNESDAY INTO THURSDAY. THIS COULD BRING ANOTHER ROUND OF MODERATE
TO HEAVY RAINFALL TO THE AREA.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...AREAS OF IFR CIGS POSSIBLY TO SPREAD INTO PHL/ILG MID OR LATE
MORNING. CIGS WILL BE AN OCNL PBLM TODAY AND CERTAINLY NOT AN ALL
VFR DAY. ESE WIND INCREASING WITH GUSTS THIS AFTN TO NEAR 20 KT.
PLEASE FOLLOW TAF ADJUSTMENTS AS THE DETERIORATING CONDITIONS
UNFOLD.
TONIGHT...IFR CIGS BECOMING WIDESPREAD WITH VSBY LOWERING TO LESS
THAN A MILE LATER AT NIGHT WITH A SMALL CHC OF LIFR CONDS IN
PATCHY DENSE FOG...ESPECIALLY E PA AND COASTAL S NJ. THIS WITH
SREF CIG VSBY PROB SUPPORT FROM THEN 09Z/18 SREF.
THE KPHL TAF HAS BEEN ADJUSTED WITH FOG LATE. 18Z TAFS WILL ATTEMPT
A MORE COMPLETE PICTURE OF ANTICIPATED IFR-LIFR CONDITIONS LATER
THU NIGHT-FRI MORNING.
FRIDAY...IFR CONDITIONS EARLY IN DRIZZLE FOG WITH POSSIBLE VFR
LATE. CHANCE OF RAIN/THUNDERSTORMS BY AFTERNOON. GUSTY SOUTH WINDS
AROUND 25-30 KNOTS POSSIBLE. LLWS POSSIBLE KACY LATE IN THE DAY.
OUTLOOK...
FRIDAY NIGHT...MVFR/IFR CONDITIONS EXPECTED WITH A PERIOD OF HEAVY
RAIN AND THUNDERSTORMS POSSIBLE.
SATURDAY...LINGERING SHOWERS AND POSSIBLE MVFR/IFR EARLY, MAINLY
TOWARD THE COAST. IMPROVING TO VFR DURING THE DAY. GUSTY WEST WINDS
20-25 KNOTS.
SATURDAY NIGHT-SUNDAY NIGHT...VFR CONDITIONS EXPECTED.
MONDAY...MOSTLY VFR, POSSIBLE NEAR MVFR WITH SHOWERS.
&&
.MARINE...
FOG HAS BEEN ADDED TO THE FCST IN THE 930 AM PACKAGE.
A WARM FRONT WILL MOVE BY TO THE N TODAY AND SELY FLOW WILL
BECOME SLY AND INCREASE WELL INTO TONIGHT. THIS WILL CAUSE SEAS TO
INCREASE AS WELL. THEREFORE, A SCA IS BEING RAISED BEGINNING AT
19/00Z. AT THIS POINT, IT IS ONLY FOR THE OCEAN, BUT MAY NEED TO
BE EXPANDED FOR AT LEAST THE LOWER PORTION OF DEL BAY, BUT
CONFIDENCE IS LOWER HERE.
OUTLOOK...
A STRONG COLD FRONT WILL MOVE ACROSS THE WATERS FRIDAY NIGHT INTO
SATURDAY. WINDS ARE EXPECTED TO INCREASE AHEAD OF THE FRONT, AND
COULD APPROACH GALE FORCE. THERE IS A STRONG FLOW ABOVE THE SURFACE,
BUT IT MAY HAVE TROUBLE MIXING DOWN IN THE SOUTHERLY FLOW. FOR NOW,
A SMALL CRAFT ADVISORY WILL BE IN EFFECT, AND WE WILL LET THE NEXT
SHIFT SEE IF A GALE WARNING WILL BE NEEDED. ADVISORY LEVELS WINDS
AND/OR SEAS WILL LIKELY CONTINUE INTO A PART OF SATURDAY. AS HIGH
PRESSURE BUILDS ACROSS THE NORTHEAST THEN OFFSHORE EARLY NEXT WEEK,
AN EASTERLY FLOW WILL DEVELOP ACROSS THE AREA. WINDS COULD CONTINUE
TO GUST NEAR ADVISORY LEVELS THROUGH MONDAY, AND SEAS COULD REMAIN
AROUND 4-5 FEET OR HIGHER WITH THE EASTERLY FETCH.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 PM EDT FRIDAY
FOR ANZ450>455.
&&
$$
SYNOPSIS...DRAG/ROBERTSON
NEAR TERM...DRAG 942
SHORT TERM...DRAG/NIERENBERG 942
LONG TERM...ROBERTSON
AVIATION...DRAG/ROBERTSON 942
MARINE...DRAG/NIERENBERG/ROBERTSON
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
854 AM EDT THU APR 18 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE COAST OF NOVA SCOTIA LATER TODAY,
ALLOWING A WARM FRONT TO LIFT THROUGH THE AREA THIS EVENING. A
STRONG COLD FRONT WILL MOVE THROUGH THE AREA FRIDAY NIGHT INTO
EARLY SATURDAY MORNING AS AN AREA OF LOW PRESSURE MOVES THROUGH
THE GREAT LAKES AND INTO EASTERN CANADA. HIGH PRESSURE BUILDS
ACROSS THE NORTHEAST SUNDAY INTO MONDAY. A WEAK DISTURBANCE MAY
DEVELOP OFF THE SOUTHEAST COAST AND AFFECT THE AREA LATE MONDAY
INTO TUESDAY. ANOTHER COLD FRONT IS FORECAST TO AFFECT THE AREA
LATE WEDNESDAY OR THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
838 AM ESTF UPDATE A LITTLE EARLY FOR ISOLATED AND OR SCT SHOWERS...
MOSTLY E MD THIS MORNING AND E PA THIS AFTN PER RAP AND MULTIPLE
MODELS SPEWING MINOR AMTS OF NUISANCE SHOWERS. ALSO INCREASED
GUSTS THIS AFTN ACROSS E PA TO THE DEL VALLEY.
BLAME IT ON A WARM FRONT...GENERAL WAA.
CONTINUE TO NOTICE A SPIKE IN RH EARLY THIS AFTN..VIA TSECS...WHICH
SIGNALS BETTER LIFT. RAP SUGGESTS TOPS TO MAYBE 17000 FT.
.01 TO .02/HR SHOWERS INCREASING NOW OVER E MD INTO N DEL WILL
BECOME THEIR MOST EXPANSIVE DURING THE EARLY AFTN AS THEY MOVE
THROUGH E PA AND W NJ.
TONIGHT...CONSIDERABLE LOW CLOUDINESS AND A STRONGER SLY FLOW AS THE
CDFNT TO THE W ADVANCES TWD THE REGION. THERE ARE MODEL INDICATIONS
OF A DENSE FOG PROBLEM HERE AND THERE DESPITE BL WINDS OF ALMOST
20 KT. SUSPECT CIGS WILL LOWER DURING THE NIGHT WITH VSBY AT ITS
LOWEST NEAR 1 MI TOWARD DAWN FRIDAY.
&&
.SHORT TERM /FRIDAY/...
FRIDAY...EARLY IN THE DAY FOG LIFTS AS WE BECOME MORE DEFINED WITHIN
THE WARM SECTOR OF THE SYSTEM, AHEAD OF THE APPROACHING COLD FRONT.
WE EXPECT A WARM, BREEZY MIDDAY/AFTERNOON. A WEAK SHORT WAVE MAY
CROSS THE AREA VERY LATE IN THE DAY AHEAD OF THE APPROACHING COLD
FRONT WHICH COMBINED WITH SOME WEAK AFTERNOON INSTABILITY MAY
SPARK A FEW SHOWERS/THUNDERSTORMS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
FRIDAY NIGHT...THE COLD FRONT IS FORECAST TO MOVE INTO OUR WESTERN
AREAS AROUND OR SHORTLY AFTER SUNSET AND MOVE EASTWARD THROUGH THE
NIGHT. WITH PW VALUES NEAR 1.5 INCHES, A PERIOD OF HEAVY RAIN IS
POSSIBLE. THERE IS SOME WEAK INSTABILITY AHEAD OF THE FRONT...MUCAPES
NEAR 200-300 J/KG, LI`S NEAR -1 TO -2, K-INDEX VALUES IN THE
30S...SO SOME EMBEDDED THUNDERSTORMS ARE POSSIBLE. RAINFALL
AMOUNTS WILL BE ENHANCED WHERE/IF THUNDERSTORMS DO DEVELOP. THE
GOOD NEWS IS THE FRONT IS FORECAST TO BE FAIRLY PROGRESSIVE AND
MOVE THROUGH THE AREA OVERNIGHT AND BE OFFSHORE BY SUNRISE
SATURDAY WHICH SHOULD LIMIT ANY FLOOD POTENTIAL TO THE URBAN/POOR
DRAINAGE TYPE.
SOME LINGERING LIGHT RAIN IS POSSIBLE, MAINLY TOWARD THE COAST,
EARLY SATURDAY AS THE FRONT PUSHES FARTHER AWAY FROM THE AREA.
BEHIND THE FRONT, A GUSTY WESTERLY FLOW WILL DEVELOP.
HIGH PRESSURE WILL BUILD ACROSS THE NORTHEAST SATURDAY NIGHT INTO
SUNDAY WHICH WILL PROVIDE DRY WEATHER FOR THE REGION. THE HIGH TRIES
TO RETREAT NORTHEASTWARD ON MONDAY, BUT WE MAY STILL REMAIN UNDER
THE GRASP OF THE FAR SOUTHERN EXTEND OF THE HIGH. THICKNESSES FAIL
TO RECOVER SUNDAY INTO MONDAY, AND WITH AN EASTERLY FLOW ACROSS THE
AREA TEMPERATURES ARE FORECAST TO BE A FEW DEGREES BELOW NORMAL. AS
THE HIGH RETREATS MONDAY INTO MONDAY NIGHT, A WEAK SURFACE TROUGH IS
FORECAST TO DEVELOP OFFSHORE OF THE SOUTHEAST STATES AND BEGIN
NOSING ITS WAY TOWARD OUR AREA. WITH A COUPLE OF WEAK SHORT WAVES
MOVING ACROSS THE AREA, WE COULD HAVE SOME PRECIPITATION DEVELOP AND
MOVE ACROSS THE AREA. SCATTERED SHOWERS COULD CONTINUE INTO TUESDAY
WITH A COUPLE OF WEAK SHORT WAVES EMBEDDED IN THE SOUTHWEST FLOW
ALOFT.
ANOTHER COLD FRONT IS FORECAST TO AFFECT THE AREA SOMETIME LATE
WEDNESDAY INTO THURSDAY. THIS COULD BRING ANOTHER ROUND OF MODERATE
TO HEAVY RAINFALL TO THE AREA.
&&
.AVIATION /13Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...AREAS OF IFR CIGS POSSIBLY TO SPREAD INTO PHL/ILG MID OR LATE
MORNING. CIGS WILL BE AN OCNL PBLM TODAY AND CERTAINLY NOT AN ALL
VFR DAY. ESE WIND INCREASING WITH GUSTS THIS AFTN TO NEAR 20 KT.
TONIGHT...IFR CIGS BECOMING WIDESPREAD WITH VSBY LOWERING TO LESS
THAN A MILE LATER AT NIGHT WITH A SMALL CHC OF LIFR CONDS IN
PATCHY DENSE FOG...ESPECIALLY E PA AND COASTAL S NJ. THIS WITH
SREF CIG VSBY PROB SUPPORT FROM THEN 09Z/18 SREF.
OUTLOOK...
FRIDAY...MVFR/IFR CONDITIONS POSSIBLE EARLY WITH POSSIBLE VFR LATE.
DRIZZLE/FOG EARLY AND CHANCE OF RAIN/THUNDERSTORMS BY AFTERNOON.
GUSTY SOUTH WINDS AROUND 25-30 KNOTS POSSIBLE.
FRIDAY NIGHT...MVFR/IFR CONDITIONS EXPECTED WITH A PERIOD OF HEAVY
RAIN AND THUNDERSTORMS POSSIBLE.
SATURDAY...LINGERING SHOWERS AND POSSIBLE MVFR/IFR EARLY, MAINLY
TOWARD THE COAST. IMPROVING TO VFR DURING THE DAY. GUSTY WEST WINDS
20-25 KNOTS.
SATURDAY NIGHT-SUNDAY NIGHT...VFR CONDITIONS EXPECTED.
MONDAY...MOSTLY VFR, POSSIBLE NEAR MVFR WITH SHOWERS.
&&
.MARINE...
A WARM FRONT WILL MOVE BY TO THE N TODAY AND SELY FLOW WILL BECOME
SLY AND INCREASE WELL INTO TONIGHT. THIS WILL CAUSE SEAS TO
INCREASE AS WELL. THEREFORE, A SCA IS BEING RAISED BEGINNING AT
19/00Z. AT THIS POINT, IT IS ONLY FOR THE OCEAN, BUT MAY NEED TO BE
EXPANDED FOR AT LEAST THE LOWER PORTION OF DEL BAY, BUT CONFIDENCE
IS LOWER HERE.
OUTLOOK...
A STRONG COLD FRONT WILL MOVE ACROSS THE WATERS FRIDAY NIGHT INTO
SATURDAY. WINDS ARE EXPECTED TO INCREASE AHEAD OF THE FRONT, AND
COULD APPROACH GALE FORCE. THERE IS A STRONG FLOW ABOVE THE SURFACE,
BUT IT MAY HAVE TROUBLE MIXING DOWN IN THE SOUTHERLY FLOW. FOR NOW,
A SMALL CRAFT ADVISORY WILL BE IN EFFECT, AND WE WILL LET THE NEXT
SHIFT SEE IF A GALE WARNING WILL BE NEEDED. ADVISORY LEVELS WINDS
AND/OR SEAS WILL LIKELY CONTINUE INTO A PART OF SATURDAY. AS HIGH
PRESSURE BUILDS ACROSS THE NORTHEAST THEN OFFSHORE EARLY NEXT WEEK,
AN EASTERLY FLOW WILL DEVELOP ACROSS THE AREA. WINDS COULD CONTINUE
TO GUST NEAR ADVISORY LEVELS THROUGH MONDAY, AND SEAS COULD REMAIN
AROUND 4-5 FEET OR HIGHER WITH THE EASTERLY FETCH.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 PM EDT FRIDAY
FOR ANZ450>455.
&&
$$
SYNOPSIS...ROBERTSON/DRAG 854
NEAR TERM...DRAG/NIERENBERG 854
SHORT TERM...DRAG/NIERENBERG 854
LONG TERM...ROBERTSON
AVIATION...DRAG/ROBERTSON 854
MARINE...DRAG/NIERENBERG/ROBERTSON 854
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
139 PM EDT THU APR 18 2013
.SYNOPSIS...
A WEAK FRONT WILL SLOWLY LIFT BACK NORTH AS A WARM FRONT LATER
TODAY...AS HIGH PRESSURE SLIDES OFF THE NEW ENGLAND COAST. A
STRONG COLD FRONT WILL APPROACH FROM THE WEST ON FRIDAY AND MOVE
ACROSS THE MID ATLANTIC FRIDAY NIGHT. HIGH PRESSURE BUILDS ACROSS
THE NORTHEAST OVER THE WEEKEND AS A FRONTAL BOUNDARY REMAINS
STALLED OFF THE SOUTHEAST COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE LATEST SURFACE ANALYSIS INDICATES A 1032MB HIGH CENTERED OVER
THE MARITIME PROVINCES OF CANADA...WITH A COMPLEX AREA OF LOW
PRESSURE AND ASSOCIATED COLD FRONT LIFTING THROUGH THE MID-
MISSISSIPPI VALLEY. AN OLD WEAK FRONTAL BOUNDARY HAS NOW LARGELY
LIFTED N OF THE AREA WITH ONLY A FEW LINGERING SHOWERS CLIPPING NW
DORCHESTER COUNTY. THROUGH THE LATE MORNING AND AFTERNOON...THE
REGION WILL BE UNDER THE INFLUENCE OF STRENGTHENING SW FLOW ALOFT
AND S/SE FLOW AT THE SURFACE AROUND THE WESTERN PERIPHERY OF THE HIGH.
THIS WILL HELP SCOUR OUT LOW CLOUDS AND SHOULD KEEP THE AFTN
MAINLY DRY UNDER A PARTLY SUNNY SKY. LOW LEVEL THICKNESSES SUGGEST
HIGHS WILL REMAIN ABOVE AVG...INTO THE LWR 80S SOUTH CENTRAL
VA...AROUND 80 MUCH OF CENTRAL VA...AND IN THE MID- UPPER 70S ACRS
THE NORTH AND CLOSER TO THE COAST. (LOCALLY IN THE 60S ON THE COAST
OF THE EASTERN SHORE).
ONE EXCEPTION TO THIS WILL BE THE IMMEDIATE ATLANTIC COAST OF THE
EASTERN SHORE FROM OCEAN CITY TO CHINCOTEAUGE. THE LATEST
GUIDANCE SUGGESTS THAT THE FRONT DOES NOT CLEAR THE IMMEDIATE
COAST AS THERE WILL NOT BE ENOUGH GRADIENT TO OVERCOME THE
INFLUENCE OF SSTS AROUND 50F. THIS WILL ALLOW LOW-LEVEL EASTERLY
FLOW TO CONTINUE ALONG WITH STRATUS AND FOG LINGERING THROUGH MUCH
OF THE DAY. THIS SHOULD HOLD HIGHS IN THE UPPER 50S TO AROUND 60.
FOR TONIGHT...CAN`T RULE OUT AN ISOLATED SHRA/TSRA ACRS THE
PIEDMONT BUT WILL KEEP FCST DRY FOR NOW WITH LITTLE TO TRIGGER FOR
PRECIP. MODELS BEGIN TO SHOW INCREASING LOW LEVEL MOISTURE AFTER
MIDNIGHT SO MOST AREAS BECOME CLOUDY PRIOR TO DAYBREAK FRI. VERY
WARM UNDER STRENGTHENING SOUTHERLY FLOW AND HAVE GENLY GONE ON THE
WARM SIDE OF GUIDANCE WITH LOWS IN THE LWR 60S FOR MUCH OF THE
CWA...LOCALLY IN THE 50S NEAR THE COAST. DUE TO WIND/MIXING THINK
FOG WILL GENLY NOT BE AN ISSUE DESPITE THE INCREASE IN LOW LEVEL
MOISTURE...EXPECT IT TO BE MORE OF A STRATUS EVENT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
OVERALL THERE IS LITTLE CHANGE WITH RESPECT TO TIMING OF THE COLD
FRONT LATE FRI/FRI NIGHT. MODELS CONTINUE TO SHOW SOME LIGHT QPF
AMOUNTS WELL OUT AHEAD OF THE FRONT EARLY FRI MORNING ACRS SE
VA/NE NC...SO RETAIN A LOW CHC POP IN THESE AREAS FRI MORNING.
THIS SHOULD NOT AMOUNT TO MUCH HOWEVER AS MODEL SOUNDINGS ARE VERY
DRY ALOFT UNDER STRONG SW FLOW. OTHER THAN A FEW SHRA...DO NOT
EXPECT TO HAVE MUCH ON THE RADAR THROUGH ABOUT 18-21Z OR SO FRI
AFTN. THIS WILL ALLOW FOR PARTIAL CLEARING LATE IN THE MORNING
ALONG WITH BREEZY SSW FLOW. HIGHS SHOULD AGAIN REACH INTO THE
UPPER 70S TO LOWER 80S FOR MOST OF THE REGION.
NAM/GFS DIFFER SOMEWHAT IN THEIR DEPICTION OF THE FORCING (WITH
THE NAM BEING DEEPER THROUGH THE COLUMN THAN THE GFS). TIMING IS
QUITE SIMILAR HOWEVER...PROGGED TO ARRIVE IN THE FAR WESTERN PORTION
OF THE AREA LATE FRIDAY AFTERNOON...INTO CENTRAL VA BETWEEN 21Z
AND 00Z...AND TO THE COAST AFTER 03Z. THE NAM IS ALSO STILL A BIT MORE
GENEROUS WITH INSTABILITY THAN THE GFS WITH VALUES ON THE ORDER OF
~750-1000 J/KG OVER S-CENTRAL VA AND INTERIOR NE NC ALONG WITH
40-50KT OF DEEP LAYER SHEAR. IF THIS WERE TO VERIFY...THUNDERSTORMS
CAPABLE OF PRODUCING STRONG WIND GUSTS ARE POSSIBLE. HOWEVER...THE
THERMODYNAMIC PROFILE SHOULD QUICKLY STABILIZE LATER IN THE
EVENING AS THE FRONT BECOMES MORE ANA-FRONTAL. ALSO...THE HIGHEST
SHEAR VALUES ARE AFTER THIS STABILIZING EFFECT DUE TO THE UPPER
JET AND STRONGER HEIGHT FALLS AT H5 LAGGING BEHIND BY SEVERAL
HUNDRED MILES. OVERALL...THIS SETUP SUGGEST THE POTENTIAL FOR SOME
LOCALLY STRONG WIND GUSTS...BUT NOT A SIGNIFICANT SEVERE OUTBREAK.
SPC SEEMS TO CONCUR AND AREA STILL IS ONLY IN A "SEE TEXT" RATHER
THAN A SLIGHT RISK. THE UPPER JET DOES BECOME FAVORABLY SETUP WITH
LOCAL AREA IN RRQ FORCING FOR SEVERAL HRS OF MODERATE TO SOMEWHAT
HEAVY RAIN THROUGH THE OVERNIGHT HRS..AND PRECIPITABLE WATER
VALUES CLIMB TO 1.50 TO 1.70". MOST OF THE CWA CAN EXPECT TO
RECEIVE QPF AMOUNTS OF 0.75 TO 1.25"...WITH HIGHER AMOUNTS MOST
LIKELY OCCURRING ACRS SE VA/NE NC WHERE RAIN WILL CONTINUE THROUGH
SOME OF THE DAY ON SATURDAY (AND LOCALLY HIGHER AMOUNTS WILL BE
POSSIBLE DUE TO THE CONVECTIVE NATURE OF THE PRECIP INITIALLY).
STILL DO NOT SEE THIS EVENT LEADING TO ANYTHING MORE THAN
MINOR/NUISANCE FLOODING IN POOR DRAINAGE AREAS AS BULK OF THE BEST
FORCING OCCURS POST FRONTAL WITH TEMPERATURES IN THE 50S AND
60S...AS WELL AS FACT THAT APRIL FLASH FLOOD EVENTS ARE RARE IN
THE AKQ CWA. LOWS RANGE FROM THE UPPER 40S NW TO THE MID 50S SE.
BULK OF PRECIP ENDS ACRS THE NW AFTER 06Z...BUT PERSISTS WELL PAST
12Z FOR FAR SE SECTIONS. HIGH PRESSURE BUILDS IN FORM THE NORTHWEST
SATURDAY WITH DRYING COMMENCING FROM NW TO SE. HIGH TEMPERATURES
WILL BE MUCH COOLER AND WILL GENLY BE IN THE LOWER TO MID 60S (NOT
A LOT OF DOWNSLOPING TO OFFSET CAA). HIGHS ONLY IN THE LOW 60S
(WITH AFTN TEMPS IN THE UPPER 50S) POSSIBLE OVER SE COASTAL AREAS
AS CLOUD COVER AND COOL ONSHORE NNE FLOW LINGERS INTO THE
AFTERNOON.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
GOING WITH A COMBINATION OF THE 12Z GFS AND 12Z ECMWF FOR THE
EXTENDED PERIOD...BUT LEANING TWD THE ECMWF IN THE FIRST PART OF
THE PERIOD...THEN LEANING TWD THE GFS FOR END OF THE PERIOD. DRY
WX FOR SAT NGT INTO SUN NGT...AS HI PRES BLDS ACRS THE GRT LKS AND
INTO NEW ENGLAND. THIS WILL MAKE FOR A CHILLY DAY SUNDAY W/ HIGHS
AT LEAST 10 DEGREES BELOW AVG...ONLY LOWER 60S INLAND WITH UPPER
50S NEAR THE COAST DUE TO COOL NE FLOW). THE CNTR OF THAT HI WILL
MOVE INTO THE NRN ATLC MON THRU TUE...AS AN INVERTED TROF DEVELOPS
ALNG THE SE/MID ATLC CST WITH WEAK LO PRES FORMING ALNG IT AND
MOVNG NNE UP THE CST. THIS WILL PRODUCE A MOIST ONSHORE FLO...WITH
A SLGT CHC OR CHC OF SHOWERS OVR THE REGION. A COLD FRONT WILL
THEN APPROACH FM THE W LATE WED...WITH AT LEAST A SLGT CHC FOR
MORE SHOWERS. MIN TEMPS WILL RANGE FM THE UPR 30S TO UPR 40S SUN
AND MON MORNGS...IN THE LWR 40S TO LWR 50S TUE MORNG...AND IN THE
UPR 40S TO MID 50S WED MORNG.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
WARM FRONT HAS MOVED NORTH OF THE AREA. GENERALLY SOUTHERLY FLOW
ACROSS THE AREA AND THIS WILL CONTINUE THROUGH THE NIGHT. CAN SEE
FOG STILL ALONG THE MD COAST AND MODELS ALL EXPAND THAT WEST WITH
TIME ACROSS SBY AFTER SUNSET. TIMED SBY TO START COMING DOWN BY
03Z AND CONTINUE TO BE IFR THROUGH 14Z. THINK ENOUGH MIXING WILL
BE OCCURRING BY THEN WITH THE SUN UP TO GET RID OF LOW CLOUDS.
BUFKIT SHOWS THESE CLOUDS ON BOTH THE RAP AND NAM MODELS TO BE
QUITE THIN. THE STATISTICAL GUIDANCE DOES NOT CLEAR IT OUT BUT IT
HAS BEEN HOLDING ON TO THE LOW CEILING TOO LONG THIS MORNING. ALSO
THE MODELS KEEP TRYING TO BRING THE OTHER TAF SITES DOWN TO IFR
AFTER MIDNIGHT BUT WITH 10 KTS OF WINDS AND ALL MODELS AGREEING
THAT THE MOISTURE IS CONFINED BELOW 925 MB THINK THE MIXING WILL
KEEP THE LOW CLOUDS AWAY OVERNIGHT. THEN ON FRIDAY WITH STRONG
COLD FRONT APPROACHING WILL HAVE BKN CU DEVELOP ACROSS THE AREA
DURING THE MORNING. THE PRECIPITATION WITH THE FRONT WILL REACH
RIC NEAR 00Z AND THERE WILL BE SOME THUNDERSTORMS ALONG THE
LEADING EDGE OF THE FRONT. MORE RAIN WILL CONTINUE FOR SEVERAL
HOURS BEHIND THE FRONT. THIS WILL BRING IFR CONDITIONS TO ALL TAF
SITES FOR FRIDAY NIGHT. CONDITIONS WILL IMPROVE RAPIDLY ON SAT
DURING THE MORNING WITH VFR CONDITIONS EXPECTED ALL AREAS BY
AFTERNOON AND CONTINUING INTO SUNDAY. COULD SEE SOME MVFR OR IFR
CONDITIONS RETURN BY MONDAY WITH BEST CHANCES NEAR THE COAST.
&&
.MARINE...
STARTED SCA FOR THE BAY AT 4PM. MANY OF THE HIGH RES MODELS
INDICATE SE/S WINDS INCREASING TO NEAR 20 KNOTS TOWARD EVENING AND
CONTINUING UNTIL AROUND OR SHORTLY AFTER MIDNIGHT. A LULL IN THE
WIND WILL THEN OCCUR UNTIL LATE FRIDAY MORNING...WHEN S WINDS
INCREASE ONCE AGAIN. KEPT SCA GOING THROUGH LATE FRIDAY NIGHT
SINCE THE LULL SHOULD BE LESS THAN 12 HOURS.
PREVIOUS DISCUSSION...
A WEAK FRNT WILL SLOWLY LIFT N TDY AS A WARM FRNT...WITH 10-15 KT
E WINDS BCMG SE 15 KT OR LESS THIS AFTN. SOUTHERLY FLOW FURTHER
INCREASES LATE TNGT INTO FRI MRNG AS THE PRES GRADIENT TIGHTENS UP
AHEAD OF AN APPROACHING COLD FRNT. SCA CONDITIONS WILL BE LIKELY
BY THU NGT/FRI OVER THE WTRS...AND PERHAPS CONTINUING INTO ERLY
SAT. HAVE GONE AHEAD AND HOISTED A SCA OVER THE COASTAL WATERS FOR
SEAS AOA 5 FT AND WINDS UP TO 25 KT PSBL. ALSO ISSUED A SCA FOR
THE BAY/SOUND FRI MIDDAY THRU EVENG WITH 20-25 KT WINDS EXPECTED
AHEAD OF THE FRNT. WINDS BEHIND THE FRNT (FROPA IS FRI NGT) MAY BE
MARGINAL OR JUST BLO SCA THRESHOLDS...SO WILL END THE HEADLINE
WITH THE FROPA FOR NOW. ALSO HELD OFF WITH THE RIVERS FOR NOW WITH
NOT ENUF CONFIDENCE IN A LATE 3RD PERIOD SCA THERE.
EXPECT A LULL IN WINDS DURING SAT AFTN...FOLLOWED BY A SURGE OF
COLDER AIR ON NE WINDS SAT NGT THRU SUN...AS STRONG SFC HI PRES BLDS
OVER THE GREAT LAKES.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR ANZ630>632-
634.
SMALL CRAFT ADVISORY FROM NOON FRIDAY TO 4 AM EDT SATURDAY FOR
ANZ633.
SMALL CRAFT ADVISORY FROM 4 AM FRIDAY TO 7 AM EDT SATURDAY FOR
ANZ654.
SMALL CRAFT ADVISORY FROM 10 AM FRIDAY TO 7 AM EDT SATURDAY
FOR ANZ656-658.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 7 AM EDT
SATURDAY FOR ANZ650-652.
&&
$$
SYNOPSIS...LKB
NEAR TERM...AJZ/LKB
SHORT TERM...AJZ/LKB
LONG TERM...TMG
AVIATION...JAB
MARINE...MAS/LSA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
250 PM CDT THU APR 18 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 249 PM CDT THU APR 18 2013
IMPRESSIVE DEFORMATION SNOW EVENT WELL UNDERWAY...WITH STRONG FGEN
NOTED IN THE H8-H5 LAYER. SEEING CONVECTIVE ELEMENTS COMING UP OUT
OF IOWA...WHICH IS AN INDICATION OF THE INSTABILITY PRESENT...WITH
SEVERAL HEAVY BANDS OF SNOW NOTED ON RADAR AS A RESULT. HAVE
GOTTEN REPORTS OF AROUND 2 INCHES PER HOUR OUT IN WRN MN THIS
AFTERNOON...AND EXPECT THESE SORTS OF RATES TO CONTINUE THROUGH
THE AFTERNOON.
THROUGH TONIGHT...FOLLOWED THE RAP FAIRLY CLOSELY FOR FORECAST
UPDATES TODAY...AS IT HAS HAD A PRETTY GOOD HANDLE ON HOW THINGS
HAVE UNFOLDED ALL DAY. AS A RESULT...BOOSTED SNOW TOTALS SOME
WITHIN THE HEART OF THE BAND FROM REDWOOD FALLS UP THROUGH ST.
CLOUD...WITH 6 INCH AMOUNTS CREEPING EAST TO BE ACROSS THE EAST
END OF THE WARNING COUNTIES NOW...WITH SNOW TOTAL AT MINNEAPOLIS
INCREASED FROM AROUND 3 INCHES TO 6 INCHES. IF THE RAP WERE TO BE
BELIEVED /WHICH BASED ON REPORTS SEEN SO FAR...DO NOT SEE WHY IT
CAN NOT BE/...THEN WE WILL LIKELY END UP WITH A BAND OF 10 TO 12
INCHES FROM GRANITE FALLS OVER TO NEW ULM AND UP TO LONG PRAIRIE
OVER TO MORA. WITH UPDATES MADE TO FORECAST TODAY...DID ADD TODD
COUNTY TO THE WARNING AND COULD HAVE VERY EASILY ADDED
STEVENS AND DOUGLAS COUNTIES OUT WEST...ALONG WITH ANOTHER ROW OF
COUNTIES TO THE EAST OF THE WARNING THAT WOULD INCLUDE THE REST OF
THE TWIN CITIES. IN FACT...AS OF THE WRITING OF THIS...THINKING
WE WILL GO AHEAD AND EXPAND THE WARNING EAST AND WEST WHEN DONE
WITH THIS AFD TO INCLUDE ALL OF THE TWIN CITIES METRO AREA.
HEAVY SNOW WILL START LETTING UP AFTER 21Z SW OF THE MN
RIVER...BETWEEN 0Z AND 3Z ALONG I-94 FROM THE TWIN CITIES UP
THROUGH ST. CLOUD...WITH HEAVY SNOW PULLING OUT OF THE NRN CWA
SHORTLY AFTER 06Z. LIGHT SNOW WILL CONTINUE THROUGH TONIGHT...WITH
LIGHT SNOW SHOWERS CONTINUING THROUGH THE DAY ACROSS WRN
WI ON FRIDAY...THOUGH MAJORITY OF ACCUMULATIONS WILL BE COMING
NOW THROUGH 12Z FRIDAY. FOR FRIDAY...ANY ADDITIONAL ACCUMULATIONS
WILL BE UNDER AN INCH.
AT 230 PM...THE RAIN/SNOW LINE WAS LOCATED NEAR AN ALBERT LEA
THROUGH RICE LAKE LINE...AND AGAIN GENERALLY FOLLOWED THE
RAP...WITH ALL SNOW FINALLY BREAKING OUT IN THE EAU CLAIRE AREA
AROUND 3Z.
AS FOR TEMPERATURES...CLOUD COVER AND NW WINDS WILL RESULT IN
FAIRLY STEADY TEMPERATURES THROUGH FRIDAY...WITH LOWS TONIGHT
FALLING BACK INTO THE UPPER 20S/LOWER 30S WHILE HIGHS ON FRIDAY
STAY MIRED IN THE 30S...OR ABOUT 20 DEGREES BELOW NORMAL.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 441 AM CDT THU APR 18 2013
SNOW WILL TAPER OFF ACROSS THE EASTERN FORECAST AREA ON FRIDAY AS
THE NEARLY STACKED LOW MOVES ACROSS THE GREAT LAKES. ADDITIONAL
SNOWFALL ACCUMS ON FRIDAY SHOULD GENERALLY VARY FROM A DUSTING
/TWIN CITIES/ TO AROUND ONE INCH /LADYSMITH TO EAU CLAIRE/. IT
WILL FEEL QUITE WINTRY ON FRIDAY...AS TEMPERATURES ONLY REACH THE
MID 30S AT THEIR WARMEST...AND COMBINE WITH BRISK NORTHWEST WINDS
OF 15 TO 25 MPH.
SURFACE HIGH PRESSURE MAKES AN APPEARANCE FOR
SATURDAY...ACCOMPANIED BY COOL AND DRY CONDITIONS. SATURDAY
MORNING LOWS WILL LIKELY RANGE BETWEEN 15 AND 20 DEGREES BELOW
NORMAL...AS CLEARING SKIES AND LIGHT WINDS ALLOW READINGS TO
TUMBLE INTO THE TEENS ACROSS THE MAJORITY OF THE FORECAST AREA.
SATURDAY HIGH TEMPERATURES WILL FOLLOW SUIT WITH RESPECT TO BEING
ON THE COLD SIDE OF NORMAL...AND ONLY REACH THE UPPER 30S AND
LOWER 40S.
THE RESPITE FROM PRECIPITATION WILL BE BRIEF...AS THE NEXT TROUGH
ARRIVES LATE IN THE WEEKEND. ISENTROPIC LIFT FROM 290-305K
BLOSSOMS ACROSS THE FORECAST AREA BETWEEN 06Z AND 12Z
SUNDAY...WHEN 50-60 POPS HAVE BEEN INCLUDED. THE ASSOCIATED COLD
FRONT MOVES ACROSS THE FORECAST AREA ON SUNDAY NIGHT AND
MONDAY...AND THEN STALLS JUST SOUTHEAST OF THE FORECAST AREA
THROUGH TUESDAY. THIS WILL YIELD PROLONGED 20-30 POPS ACROSS THE
SOUTHERN/EASTERN PARTS OF THE FORECAST AREA INTO WEDNESDAY AS THE
BAROCLINIC ZONE LOITERS NEARBY...AND INTERACTS WITH PERIODIC WEAK
MID LEVEL SHORTWAVES TRAVELING THROUGH THE WEST/SOUTHWEST FLOW.
TEMPERATURES NEXT WEEK WILL REMAIN COOLER THAN NORMAL...WITH
HIGHS/LOWS IN THE 40S/30S RESPECTIVELY. THERE
IS...HOWEVER...INDICATION OF MODERATING TEMPERATURES LATE NEXT
WEEK AS THE WESTERN RIDGE BUILDS TOWARD THE CENTRAL CONUS. HIGHS
IN THE LOW/MID 50S APPEAR ATTAINABLE BY THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 138 PM CDT THU APR 18 2013
BAND OF HEAVY SNOW SETTING UP ACROSS MN THIS AFTERNOON. SEEING
CONVECTIVE ELEMENTS COMING UP OUT OF IA INTO THE MN SNOW
BAND...WHICH FURTHER SUPPORTS THE IDEA OF HEAVY SNOW CONTINUING
THROUGH THE AFTERNOON. THE RAP HAS DONE A GREAT JOB IN HANDLING
THE EVOLUTION OF THE SNOW SO FAR...SO FOLLOWED IT CLOSELY FOR TIMING
SNOW THROUGH TERMINALS. 1/4SM TO 1SM VIS IN SNOW WILL BE COMMON
THROUGH 00Z AT ALL BUT EAU. FOR EAU...NAM CHANGES TO SNOW AT 1Z
WITH THE RAP CHANGING OVER AT 4Z. EXPECTING AMOUNTS NEAR 10 INCHES
AT RWF/STC...6 INCHES AT MSP/RNH/AXN...WITH LESS THAN 3 INCHES AT
EAU. FOR THE IMPROVEMENT...MAY BE A LITTLE SLOW IN IMPROVING
CONDITION TONIGHT/FRI MORNING...BUT LATER TAFS CAN IMPROVE THAT
TIMING. FOR WINDS...DID BUMP THEM DOWN THROUGH THE AFTERNOON AS
HEAVY SNOW APPEARS TO BE DAMPENING WINDS SOME...WITH SPEEDS
EXPECTED TO INCREASE TONIGHT AS SNOW LETS UP.
KMSP...
GIVEN RECENT RADAR TRENDS AND RAP FORECASTS...CONFIDENCE HIGH IN
HEAVY SNOW IMPACTING MSP BETWEEN 20Z AND 03Z...WITH A GRADUAL
DECREASE IN INTENSITY BETWEEN 03Z AND 06Z. HAVE INCREASED EXPECTED
SNOWFALL AMOUNTS AS A RESULT UP INTO THE 6 INCH RANGE. CONFIDENCE
DECREASES SOME WITH RATE OF IMPROVEMENT TONIGHT...THOUGH
CONFIDENCE IS HIGH IN CIGS REMAINING BELOW 1700 FT. DURING THE
MORNING INTO THE AFTERNOON...WILL SEE CIGS IMPROVE ABOVE 1700 FT.
FOR WINDS...DIMINISHED SPEEDS COMPARED TO LAMP WHILE HEAVY SNOW IS
FALLING...BUT INCREASED SPEEDS CLOSER TO LAMP GUIDANCE AS SNOW
BEGINS TO DIMINISH TONIGHT.
/OUTLOOK FOR KMSP/
SAT...VFR WITH MVFR AND -RA POSSIBLE LATE. WINDS SE AT 10G15KTS.
SUN...MVFR WITH IFR AND -RA POSSIBLE. WINDS S AT 10G15KTS.
MON...MVFR OR LOWER WITH -RA POSSIBLE. WINDS BCMG NNW 10G20KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 1 PM CDT FRIDAY FOR MNZ062-063-069-
070-076>078-082>085-091-092.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT FRIDAY FOR MNZ041-047.
WINTER STORM WARNING UNTIL 10 AM CDT FRIDAY FOR MNZ042>045-
048>061-064>068-073>075.
WI...WINTER WEATHER ADVISORY UNTIL 1 PM CDT FRIDAY FOR WIZ014>016-
023>025.
&&
$$
SHORT TERM...MPG
LONG TERM...LS
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
138 PM CDT THU APR 18 2013
.UPDATE...
18Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 441 AM CDT THU APR 18 2013
TODAY AND TONIGHT...EARLY MORNING WATER VAPOR IMAGERY TOGETHER WITH
500MB HEIGHTS AND WINDS SHOWED THE POSITIVELY TILTED LONGWAVE TROUGH
CENTERED OVER THE HIGH PLAINS WITH DEEP CONVECTION BREAKING OUT
DOWNSTREAM OF THE TROUGH AXIS FROM CENTRAL TEXAS UP THROUGH THE
GREAT LAKES REGION. A DRY SLOT ROUNDING THE BASE OF THE TROUGH WAS
EVIDENT OVER THE TEXAS/OKLAHOMA PANHANDLES UP THROUGH EASTERN
NEBRASKA. THE SURFACE LOW WAS CENTERED IN NORTHEAST MISSOURI...AND
THIS LOW IS FORECAST TO PROPAGATE INTO SOUTHEAST WISCONSIN AND
DEEPEN AS 16-20M/HR 500MB HEIGHTFALLS ASSOCIATED WITH THE MAIN
SHORTWAVE OVERSPREAD THE REGION LATER TODAY. A POWERFUL UPPER LEVEL
JET SITS ATOP A DEEP FRONTAL ZONE...AND THE BIG QUESTION FOR THIS
FORECAST PERIOD IS WHERE THIS FRONT WILL BECOME ACTIVE...AND WHAT
THE PREDOMINANT PTYPE WILL BE.
NORTHWEST TO SOUTHEAST CROSS SECTIONS DEPICT A DEEP AREA OF
FRONTOGENETIC FORCING...SO A BAND OF HEAVY SNOW IS IMMINENT LATER
TODAY. CURRENTLY EXPECTING THIS BAND TO SET UP FROM REDWOOD FALLS
UP THROUGH DULUTH MN...WHERE SNOW IS FORECAST. THE NAM 18.00 BUFR
SOUNDINGS MATCHED UP VERY WELL WITH THE MPX RAOB...SO USED THIS
TEMPERATURE PROFILE TO DETERMINE PTYPE. HOWEVER...NAM SURFACE
TEMPS WERE TOO COOL SO EXPECTING LESS ACCUMULATION THAN THE NAM
COBB OUTPUT WOULD SUGGEST...WHICH SHOWS 20/25:1 RATIOS. THE
RAIN/SNOW/SLEET LINE WILL ONCE AGAIN STRADDLE THE METRO AREA
ALLOWING FOR A WIDE RANGE OF SNOW TOTALS FROM WEST TO EAST. SREF
PLUMES SHOW 7 TO 8 INCHES AT KMSP...BUT AFTER REMOVING THE TOP
OUTLIERS HAVE MORE LIKE 6 TO 7 INCHES. BASED ON THE FORECAST
SOUNDINGS ELEVATED INSTABILITY AND WARMER LOW LEVELS FEEL THAT
THESE ARE STILL OVERDONE AND WILL LOSE SOME SNOW ACCUMULATION TO
CONVECTIVE GRAUPEL...SO HAVE AROUND 3 INCHES OF SNOW IN THE EAST
METRO...WITH UP TO 7 IN THE WEST. THE BULK OF THE PRECIP WILL FALL
THIS AFTERNOON...MAKING THE COMMUTE DIFFICULT. WILL LIKELY SEE
SNOW RATES OF 1-2 INCHES PER HOUR WITHIN THE HEAVY BAND...BUT
ANTICIPATING THIS WILL BE JUST WEST OF THE METRO AS INDICATED BY
THE HOPWRF.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 441 AM CDT THU APR 18 2013
SNOW WILL TAPER OFF ACROSS THE EASTERN FORECAST AREA ON FRIDAY AS
THE NEARLY STACKED LOW MOVES ACROSS THE GREAT LAKES. ADDITIONAL
SNOWFALL ACCUMS ON FRIDAY SHOULD GENERALLY VARY FROM A DUSTING
/TWIN CITIES/ TO AROUND ONE INCH /LADYSMITH TO EAU CLAIRE/. IT
WILL FEEL QUITE WINTRY ON FRIDAY...AS TEMPERATURES ONLY REACH THE
MID 30S AT THEIR WARMEST...AND COMBINE WITH BRISK NORTHWEST WINDS
OF 15 TO 25 MPH.
SURFACE HIGH PRESSURE MAKES AN APPEARANCE FOR
SATURDAY...ACCOMPANIED BY COOL AND DRY CONDITIONS. SATURDAY
MORNING LOWS WILL LIKELY RANGE BETWEEN 15 AND 20 DEGREES BELOW
NORMAL...AS CLEARING SKIES AND LIGHT WINDS ALLOW READINGS TO
TUMBLE INTO THE TEENS ACROSS THE MAJORITY OF THE FORECAST AREA.
SATURDAY HIGH TEMPERATURES WILL FOLLOW SUIT WITH RESPECT TO BEING
ON THE COLD SIDE OF NORMAL...AND ONLY REACH THE UPPER 30S AND
LOWER 40S.
THE RESPITE FROM PRECIPITATION WILL BE BRIEF...AS THE NEXT TROUGH
ARRIVES LATE IN THE WEEKEND. ISENTROPIC LIFT FROM 290-305K
BLOSSOMS ACROSS THE FORECAST AREA BETWEEN 06Z AND 12Z
SUNDAY...WHEN 50-60 POPS HAVE BEEN INCLUDED. THE ASSOCIATED COLD
FRONT MOVES ACROSS THE FORECAST AREA ON SUNDAY NIGHT AND
MONDAY...AND THEN STALLS JUST SOUTHEAST OF THE FORECAST AREA
THROUGH TUESDAY. THIS WILL YIELD PROLONGED 20-30 POPS ACROSS THE
SOUTHERN/EASTERN PARTS OF THE FORECAST AREA INTO WEDNESDAY AS THE
BAROCLINIC ZONE LOITERS NEARBY...AND INTERACTS WITH PERIODIC WEAK
MID LEVEL SHORTWAVES TRAVELING THROUGH THE WEST/SOUTHWEST FLOW.
TEMPERATURES NEXT WEEK WILL REMAIN COOLER THAN NORMAL...WITH
HIGHS/LOWS IN THE 40S/30S RESPECTIVELY. THERE
IS...HOWEVER...INDICATION OF MODERATING TEMPERATURES LATE NEXT
WEEK AS THE WESTERN RIDGE BUILDS TOWARD THE CENTRAL CONUS. HIGHS
IN THE LOW/MID 50S APPEAR ATTAINABLE BY THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 138 PM CDT THU APR 18 2013
BAND OF HEAVY SNOW SETTING UP ACROSS MN THIS AFTERNOON. SEEING
CONVECTIVE ELEMENTS COMING UP OUT OF IA INTO THE MN SNOW
BAND...WHICH FURTHER SUPPORTS THE IDEA OF HEAVY SNOW CONTINUING
THROUGH THE AFTERNOON. THE RAP HAS DONE A GREAT JOB IN HANDLING
THE EVOLUTION OF THE SNOW SO FAR...SO FOLLOWED IT CLOSELY FOR TIMING
SNOW THROUGH TERMINALS. 1/4SM TO 1SM VIS IN SNOW WILL BE COMMON
THROUGH 00Z AT ALL BUT EAU. FOR EAU...NAM CHANGES TO SNOW AT 1Z
WITH THE RAP CHANGING OVER AT 4Z. EXPECTING AMOUNTS NEAR 10 INCHES
AT RWF/STC...6 INCHES AT MSP/RNH/AXN...WITH LESS THAN 3 INCHES AT
EAU. FOR THE IMPROVEMENT...MAY BE A LITTLE SLOW IN IMPROVING
CONDITION TONIGHT/FRI MORNING...BUT LATER TAFS CAN IMPROVE THAT
TIMING. FOR WINDS...DID BUMP THEM DOWN THROUGH THE AFTERNOON AS
HEAVY SNOW APPEARS TO BE DAPPENING WINDS SOME...WITH SPEEDS
EXPECTED TO INCREASE TONIGHT AS SNOW LETS UP.
KMSP...
GIVEN RECENT RADAR TRENDS AND RAP FORECASTS...CONFIDENCE HIGH IN
HEAVY SNOW IMPACTING MSP BETWEEN 20Z AND 03Z...WITH A GRADUAL
DECREASE IN INTENSITY BETWEEN 03Z AND 06Z. HAVE INCREASED EXPECTED
SNOWFALL AMOUNTS AS A RESULT UP INTO THE 6 INCH RANGE. CONFIDENCE
DECREASES SOME WITH RATE OF IMPROVEMENT TONIGHT...THOUGH
CONFIDENCE IS HIGH IN CIGS REMAINING BELOW 1700 FT. DURING THE
MORNING INTO THE AFTERNOON...WILL SEE CIGS IMPROVE ABOVE 1700 FT.
FOR WINDS...DIMINISHED SPEEDS COMPARED TO LAMP WHILE HEAVY SNOW IS
FALLING...BUT INCREASED SPEEDS CLOSER TO LAMP GUIDANCE AS SNOW
BEGINS TO DIMINISH TONIGHT.
/OUTLOOK FOR KMSP/
SAT...VFR WITH MVFR AND -RA POSSIBLE LATE. WINDS SE AT 10G15KTS.
SUN...MVFR WITH IFR AND -RA POSSIBLE. WINDS S AT 10G15KTS.
MON...MVFR OR LOWER WITH -RA POSSIBLE. WINDS BCMG NNW 10G20KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 1 PM CDT FRIDAY FOR MNZ062-063-069-
070-076>078-082>085-091-092.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT FRIDAY FOR MNZ041-047.
WINTER STORM WARNING UNTIL 10 AM CDT FRIDAY FOR MNZ042>045-
048>061-064>068-073>075.
WI...WINTER WEATHER ADVISORY UNTIL 1 PM CDT FRIDAY FOR WIZ014>016-
023>025.
&&
$$
SHORT TERM...JRB
LONG TERM...LS
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1222 PM CDT THU APR 18 2013
.UPDATE...
ISSUED AT 1045 CDT THU APR 18 2013
AS OF 15Z...WATER VAPOR IMAGERY INDICATES THE MID LEVEL LONGWAVE
TROUGH EXTENDING FROM SOUTH CENTRAL CANADA INTO THE CENTRAL AND
SOUTHERN PLAINS. AN ENHANCED AREA OF MID LEVEL VORTICITY IS ALSO
NOTED OVER PORTIONS OF SOUTH DAKOTA AND NEBRASKA. ENHANCED MID
LEVEL MOISTURE IS NOTED EXTENDING FROM THE SOUTHERN
PLAINS...NORTHEAST INTO THE OHIO RIVER VALLEY. A MID LEVEL DRY
INTRUSION IS EVIDENT FROM NORTH TEXAS INTO EASTERN
KANSAS...SOUTHEASTERN NEBRASKA AND PORTIONS OF IOWA. AN AXIS MID
LEVEL DEFORMATION...TO THE WEST/NORTHWEST OF THE ENHANCED
VORTICITY EMBEDDED WITHIN THE LONGWAVE TROUGH...IS ALSO NOTED
EXTENDING FROM EASTERN NORTH DAKOTA INTO PORTIONS OF NEBRASKA.
RADAR DATA FROM KUEX INDICATES BANDED SNOWFALL CONTINUING OVER THE
EASTERN HALF OF OUR CWA...WITH NOTHING MORE THAN LIGHT SNOW OR
SNOW FLURRIES ACROSS OUR EAST. THE SURFACE WIND REMAINS VERY
STRONG ACROSS OUR AREA...SUSTAINED FROM THE NORTHWEST AT 15-25KTS
WITH HIGHER GUSTS.
THE BANDED SNOWFALL ACROSS EASTERN PORTIONS OF OUR CWA APPEARS TO
BE A DIRECT RESULT OF THE AFOREMENTIONED MID LEVEL DEFORMATION
AXIS CURRENTLY MOVING EAST ACROSS THE REGION. GUIDANCE FROM THE
NAM...OPERATIONAL GFS...EC...SREF-MEAN...AND RAP ALL SUGGEST THIS
AXIS OF DEFORMATION WILL CONTINUE MOVING EAST TODAY AND AS A
RESULT...THE BAND OF SNOWFALL CURRENTLY OVER PORTIONS OF OUR AREA
SHOULD ALSO CONTINUE MOVING EAST OUT OF OUR AREA THROUGH THIS
AFTERNOON.
GIVEN THE CURRENT SATELLITE AND RADAR TRENDS...AS WELL AS MODEL
GUIDANCE...WENT AHEAD AND CUT POPS ACROSS WEST/SOUTHWESTERN
PORTIONS OF OUR CWA THROUGH THE REMAINDER OF THE DAY. CERTAINLY
THERE COULD BE PERIODIC LIGHT SNOW OR SNOW FLURRIES OUT THAT
WAY...BUT THE CHANCES OF MEASURABLE PRECIPITATION BEING OBSERVED
THROUGH THE REST OF TODAY ARE FAR TOO LOW TO KEEP IN THE FORECAST.
WENT AHEAD LINGERED PRECIPITATION OVER OUR EAST/NORTHEAST THROUGH
EARLY TO MID-AFTERNOON...WITH DRY CONDITIONS EXPECTED FOR THE MOST
PART LATE AFTERNOON. GIVEN THE CURRENT SPEED OF THE SNOW BAND
ACROSS OUR AREA AND OBSERVATIONS FROM ACROSS THE AREA...IT SEEMS
LOGICAL THAT LOCATIONS WHO OBSERVE SNOWFALL UNDERNEATH THE BAND
COULD PICKUP AN ADDITIONAL INCH OF SNOWFALL THIS MORNING INTO THIS
AFTERNOON...AND SUCH WORDING IS CAPTURED IN THE FORECAST.
GUIDANCE SUGGESTS AN INCREASED LOW LEVEL PRESSURE GRADIENT WILL
CONTINUE PROMOTING A STRONG LOW LEVEL WIND FIELD ACROSS OUR AREA
THROUGH THIS AFTERNOON AND PERHAPS INTO THIS EVENING. GUIDANCE
ALSO SUGGESTS PERIODIC WIND ADVISORY-WORTHY WINDS WILL BE OBSERVED
ACROSS PORTIONS OF SOUTH CENTRAL NEBRASKA NEAR I-80...BUT THESE
LOCATIONS ARE ALREADY COVERED WITH A WINTER WEATHER ADVISORY.
GIVEN THE DECREASE IN SNOWFALL RATES ACROSS OUR
SOUTH/SOUTHWEST...OPTED TO ALLOW THE WINTER WEATHER ADVISORY TO
EXPIRE ACROSS OUR KANSAS COUNTIES. WITH SNOWFALL CONTINUING ACROSS
PORTIONS OF SOUTH CENTRAL NEBRASKA...WENT AHEAD AND LET THE WINTER
WEATHER ADVISORY RIDE FOR MANY OF OUR NEBRASKA COUNTIES THROUGH
21Z.
OVERALL THIS WEATHER SYSTEM IS BEHAVING AS EXPECTED AND THE
FORECAST REMAINS IN GOOD SHAPE. BESIDES THE AFOREMENTIONED
ADJUSTMENTS TO THE HEADLINES...POPS AND WEATHER GRIDS...ALSO
TWEAKED HOURLY TEMPERATURE...DEW POINT AND WIND GRIDS TO BETTER
REFLECT CURRENT CONDITIONS.
UPDATE ISSUED AT 815 AM CDT THU APR 18 2013
FYI WE ARE FORECASTING RECORD COLD HIGH TEMPS TODAY. IN THE 117
YEARS OF RECORDS AT GRI AND 106 YEARS AT HSI...HIGH TEMPS HAVE
NEVER BEEN COLDER ON APR 18TH THAN WHAT WE/RE FCSTG TODAY.
HERE ARE THE RECORDS...
GRI 40 IN 1944 1912 1910
HSI 41 IN 1944
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CDT THU APR 18 2013
MAIN FORECAST CONCERNS SURROUND THE PRECIPITATION ACROSS THE AREA
AND TEMPERATURES.
RADAR AND OBSERVATIONS SHOW PRECIPITATION ACROSS THE FORECAST
AREA THIS MORNING. TO THE NORTHWEST THIS SHOULD BE ALL SNOW WITH
SURFACE TEMPERATURES JUST BELOW FREEZING AND FORECAST SOUNDINGS
HAVE TEMPERATURES BELOW FREEZING THROUGH THE PROFILE. FURTHER TO
THE SOUTH AND EAST THERE IS SOME QUESTION. EARLIER REPORTS WERE OF
SOME SLEET AND EVEN RAIN BUT RECENT REPORTS HAVE BEEN ALL SNOW.
THE UPPER LEVEL LOW MOVES OFF TO THE NORTHEAST AND COLDER AIR
CONTINUES TO MOVE INTO THE AREA. EXPECT SNOW ACROSS THE AREA TODAY.
THE SNOW THIS MORNING HAS BEEN IN BANDS AND UNDER THE BANDS IT IS
SNOWING FAIRLY HARD...BUT BETWEEN THE SNOW IS LIGHTER. SNOW FALL
AMOUNTS ARE A BIT TRICKY. MOST OF THE SNOW WILL BE BEFORE SUN RISE
THIS MORNING WITH LESSER AMOUNTS DURING THE DAY. MODELS ARE SIMILAR
IN MOVING PRECIPITATION OUT OF THE AREA AS THE UPPER LOW MOVES OFF
TO THE NORTHEAST. EXPECT THAT SNOW WILL END ACROSS THE SOUTHWEST BY
MID AFTERNOON AND OUT OF THE NORTHEAST EARLY IN THE EVENING. THE
QUESTION FOR THIS AFTERNOON WILL BE WHETHER THE SNOW WILL CHANGE
BACK TO RAIN AS THE TEMPERATURES WARM UP. HAVE LEFT IT AS SNOW FOR
NOW EXPECTING THAT BY THE TIME IT WARMS UP THE PRECIPITATION SHOULD
BE COMING TO AN END. HIGH TEMPERATURES TODAY WILL BE IN THE 30S.
CLOUDS WILL CONTINUE THIS EVENING AFTER THE SNOW COMES TO AN END
BUT GRADUAL CLEARING FROM THE WEST IS EXPECTED LATER TONIGHT. WITH
THE CLEARING SKIES AND WINDS WEAKENING SOME DURING THE
NIGHT...EXPECT TEMPERATURES TO DROP OFF TO LOWS IN THE LOWER TO
MID 20S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 355 AM CDT THU APR 18 2013
FRIDAY MORNING THE UPPER VORTEX WILL BE MOVING INTO THE GREAT
LAKES REGION...WHILE ACROSS OUR REGION...NORTHWEST FLOW WILL BE IN
PLACE ACROSS THE CENTRAL PLAINS. MODELS INDICATE A 80KT JET STREAK
NOSING SOUTHEAST ON THE BACK SIDE OF THE TROUGH FM THE DAKOTAS
FRIDAY IN THE NW FLOW REGIME...WHICH REACHES EAST CENTRAL/EASTERN
NEB FRIDAY AFTN. FORECAST SOUNDINGS INDICATE CONVECTIVE TEMPS IN
THE MID/UPPER 40S...AND AFTN HIGHS ARE FORECAST NEAR THIS AND WITH
INCREASING DYNAMICS WITH SHEARED SHORTWAVE ENERGY AND JET...HAVE
WENT AHEAD AND INCLUDED SPRINKLE POTENTIAL FOR THE AFTN. SREF POPS
ARE FAIRLY HIGH IN THE 30 TO 40 PCNT RANGE...BUT FEEL SPRINKLES
SHOULD COVER THINGS FOR NOW.
DRY CONDITIONS BUT COOL CONDITIONS ARE FORECAST FRIDAY NIGHT WITH
LOWS IN THE UPPER 20S/LOW 30S. THE AIRMASS BEGINS TO MODERATE OVER
THE WEEKEND BEHIND THE DEPARTING UPPER TROUGH. WARM FRONT LIFTS
E/NE ON SATURDAY AND TEMPS SHOULD CLIMB CLOSER TO SEASONAL NORMALS.
A MID LEVEL SHORTWAVE TROUGH AND ASSOCIATED SFC TROUGH/COOL FRONT
TRANSLATE EAST SATURDAY NIGHT BRINGING SLIGHT CHCS FOR PCPN. THE
UPPER WAVE TRANSLATES ACROSS THE PLAINS SUNDAY WITH CONTINUED
CHCS FOR CONVECTION IN UPPER DYNAMICS.
THE WEATHER PATTERN NEXT WEEK REMAINS ACTIVE WITH AN UPPER TROUGH
OVER CANADA SWINGING SOUTH FM THE NORTHERN PLAINS MONDAY NIGHT INTO
TUESDAY. SIMILAR TO THE LAST FEW WEEKS...CONVECTIVE POTENTIAL
EXISTS AHEAD OF THE SYSTEM...WITH AIRMASS PROGGED COLD ENOUGH FOR A
RAIN/SNOW MIX OR MAYBE EVEN A CHANGE TO SNOW FOR SOME AREAS MONDAY
NIGHT. UNSEASONALLY COLD TEMPERATURES WILL RETURN FOR SEVERAL DAYS
TO START THE WORK WEEK WITH CONDITIONS DRYING OUT BEHIND THE TROUGH
TUESDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1222 PM CDT THU APR 18 2013
IFR CONDITIONS TO CONTINUE THROUGH THIS AFTERNOON AND PERHAPS THIS
EVENING...WITH VFR CONDITIONS EXPECTED THEREAFTER.
BLOWING SNOW WILL CONTINUE RESTRICTING THE VISIBILITY TO AROUND
1SM THIS AFTERNOON...AND PERHAPS INTO THIS EVENING. THE LOW LEVEL
WIND FIELD IS EXPECTED TO DIMINISH IN INTENSITY THIS EVENING THUS
ALLOWING FOR IMPROVED VISIBILITY. THE CEILING WILL VARY BETWEEN
2500FT AND 3500FT AGL THROUGH THROUGH THIS EVENING AS
WELL...BEFORE A PREVAILING VFR CEILING PRESENTS ITSELF TONIGHT
INTO TOMORROW. THE SURFACE WIND WILL REMAIN FROM THE
NORTHWEST...SUSTAINED AT AROUND 20KTS AND GUSTING NEAR 30KTS
THROUGH THIS EVENING...DECREASING TO AROUND 12KTS TONIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR
NEZ039>041-046>049-060>064-072>076-082>085.
KS...NONE.
&&
$$
1045 AM UPDATE...BRYANT
0815 AM UPDATE...HALBLAUB
SHORT TERM...JCB
LONG TERM...FAY
AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1045 AM CDT THU APR 18 2013
.UPDATE...
ISSUED AT 1045 CDT THU APR 18 2013
AS OF 15Z...WATER VAPOR IMAGERY INDICATES THE MID LEVEL LONGWAVE
TROUGH EXTENDING FROM SOUTH CENTRAL CANADA INTO THE CENTRAL AND
SOUTHERN PLAINS. AN ENHANCED AREA OF MID LEVEL VORTICITY IS ALSO
NOTED OVER PORTIONS OF SOUTH DAKOTA AND NEBRASKA. ENHANCED MID
LEVEL MOISTURE IS NOTED EXTENDING FROM THE SOUTHERN
PLAINS...NORTHEAST INTO THE OHIO RIVER VALLEY. A MID LEVEL DRY
INTRUSION IS EVIDENT FROM NORTH TEXAS INTO EASTERN
KANSAS...SOUTHEASTERN NEBRASKA AND PORTIONS OF IOWA. AN AXIS MID
LEVEL DEFORMATION...TO THE WEST/NORTHWEST OF THE ENHANCED
VORTICITY EMBEDDED WITHIN THE LONGWAVE TROUGH...IS ALSO NOTED
EXTENDING FROM EASTERN NORTH DAKOTA INTO PORTIONS OF NEBRASKA.
RADAR DATA FROM KUEX INDICATES BANDED SNOWFALL CONTINUING OVER THE
EASTERN HALF OF OUR CWA...WITH NOTHING MORE THAN LIGHT SNOW OR
SNOW FLURRIES ACROSS OUR EAST. THE SURFACE WIND REMAINS VERY
STRONG ACROSS OUR AREA...SUSTAINED FROM THE NORTHWEST AT 15-25KTS
WITH HIGHER GUSTS.
THE BANDED SNOWFALL ACROSS EASTERN PORTIONS OF OUR CWA APPEARS TO
BE A DIRECT RESULT OF THE AFOREMENTIONED MID LEVEL DEFORMATION
AXIS CURRENTLY MOVING EAST ACROSS THE REGION. GUIDANCE FROM THE
NAM...OPERATIONAL GFS...EC...SREF-MEAN...AND RAP ALL SUGGEST THIS
AXIS OF DEFORMATION WILL CONTINUE MOVING EAST TODAY AND AS A
RESULT...THE BAND OF SNOWFALL CURRENTLY OVER PORTIONS OF OUR AREA
SHOULD ALSO CONTINUE MOVING EAST OUT OF OUR AREA THROUGH THIS
AFTERNOON.
GIVEN THE CURRENT SATELLITE AND RADAR TRENDS...AS WELL AS MODEL
GUIDANCE...WENT AHEAD AND CUT POPS ACROSS WEST/SOUTHWESTERN
PORTIONS OF OUR CWA THROUGH THE REMAINDER OF THE DAY. CERTAINLY
THERE COULD BE PERIODIC LIGHT SNOW OR SNOW FLURRIES OUT THAT
WAY...BUT THE CHANCES OF MEASURABLE PRECIPITATION BEING OBSERVED
THROUGH THE REST OF TODAY ARE FAR TOO LOW TO KEEP IN THE FORECAST.
WENT AHEAD LINGERED PRECIPITATION OVER OUR EAST/NORTHEAST THROUGH
EARLY TO MID-AFTERNOON...WITH DRY CONDITIONS EXPECTED FOR THE MOST
PART LATE AFTERNOON. GIVEN THE CURRENT SPEED OF THE SNOW BAND
ACROSS OUR AREA AND OBSERVATIONS FROM ACROSS THE AREA...IT SEEMS
LOGICAL THAT LOCATIONS WHO OBSERVE SNOWFALL UNDERNEATH THE BAND
COULD PICKUP AN ADDITIONAL INCH OF SNOWFALL THIS MORNING INTO THIS
AFTERNOON...AND SUCH WORDING IS CAPTURED IN THE FORECAST.
GUIDANCE SUGGESTS AN INCREASED LOW LEVEL PRESSURE GRADIENT WILL
CONTINUE PROMOTING A STRONG LOW LEVEL WIND FIELD ACROSS OUR AREA
THROUGH THIS AFTERNOON AND PERHAPS INTO THIS EVENING. GUIDANCE
ALSO SUGGESTS PERIODIC WIND ADVISORY-WORTHY WINDS WILL BE OBSERVED
ACROSS PORTIONS OF SOUTH CENTRAL NEBRASKA NEAR I-80...BUT THESE
LOCATIONS ARE ALREADY COVERED WITH A WINTER WEATHER ADVISORY.
GIVEN THE DECREASE IN SNOWFALL RATES ACROSS OUR
SOUTH/SOUTHWEST...OPTED TO ALLOW THE WINTER WEATHER ADVISORY TO
EXPIRE ACROSS OUR KANSAS COUNTIES. WITH SNOWFALL CONTINUING ACROSS
PORTIONS OF SOUTH CENTRAL NEBRASKA...WENT AHEAD AND LET THE WINTER
WEATHER ADVISORY RIDE FOR MANY OF OUR NEBRASKA COUNTIES THROUGH
21Z.
OVERALL THIS WEATHER SYSTEM IS BEHAVING AS EXPECTED AND THE
FORECAST REMAINS IN GOOD SHAPE. BESIDES THE AFOREMENTIONED
ADJUSTMENTS TO THE HEADLINES...POPS AND WEATHER GRIDS...ALSO
TWEAKED HOURLY TEMPERATURE...DEW POINT AND WIND GRIDS TO BETTER
REFLECT CURRENT CONDITIONS.
UPDATE ISSUED AT 815 AM CDT THU APR 18 2013
FYI WE ARE FORECASTING RECORD COLD HIGH TEMPS TODAY. IN THE 117
YEARS OF RECORDS AT GRI AND 106 YEARS AT HSI...HIGH TEMPS HAVE
NEVER BEEN COLDER ON APR 18TH THAN WHAT WE/RE FCSTG TODAY.
HERE ARE THE RECORDS...
GRI 40 IN 1944 1912 1910
HSI 41 IN 1944
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CDT THU APR 18 2013
MAIN FORECAST CONCERNS SURROUND THE PRECIPITATION ACROSS THE AREA
AND TEMPERATURES.
RADAR AND OBSERVATIONS SHOW PRECIPITATION ACROSS THE FORECAST
AREA THIS MORNING. TO THE NORTHWEST THIS SHOULD BE ALL SNOW WITH
SURFACE TEMPERATURES JUST BELOW FREEZING AND FORECAST SOUNDINGS
HAVE TEMPERATURES BELOW FREEZING THROUGH THE PROFILE. FURTHER TO
THE SOUTH AND EAST THERE IS SOME QUESTION. EARLIER REPORTS WERE OF
SOME SLEET AND EVEN RAIN BUT RECENT REPORTS HAVE BEEN ALL SNOW.
THE UPPER LEVEL LOW MOVES OFF TO THE NORTHEAST AND COLDER AIR
CONTINUES TO MOVE INTO THE AREA. EXPECT SNOW ACROSS THE AREA TODAY.
THE SNOW THIS MORNING HAS BEEN IN BANDS AND UNDER THE BANDS IT IS
SNOWING FAIRLY HARD...BUT BETWEEN THE SNOW IS LIGHTER. SNOW FALL
AMOUNTS ARE A BIT TRICKY. MOST OF THE SNOW WILL BE BEFORE SUN RISE
THIS MORNING WITH LESSER AMOUNTS DURING THE DAY. MODELS ARE SIMILAR
IN MOVING PRECIPITATION OUT OF THE AREA AS THE UPPER LOW MOVES OFF
TO THE NORTHEAST. EXPECT THAT SNOW WILL END ACROSS THE SOUTHWEST BY
MID AFTERNOON AND OUT OF THE NORTHEAST EARLY IN THE EVENING. THE
QUESTION FOR THIS AFTERNOON WILL BE WHETHER THE SNOW WILL CHANGE
BACK TO RAIN AS THE TEMPERATURES WARM UP. HAVE LEFT IT AS SNOW FOR
NOW EXPECTING THAT BY THE TIME IT WARMS UP THE PRECIPITATION SHOULD
BE COMING TO AN END. HIGH TEMPERATURES TODAY WILL BE IN THE 30S.
CLOUDS WILL CONTINUE THIS EVENING AFTER THE SNOW COMES TO AN END
BUT GRADUAL CLEARING FROM THE WEST IS EXPECTED LATER TONIGHT. WITH
THE CLEARING SKIES AND WINDS WEAKENING SOME DURING THE
NIGHT...EXPECT TEMPERATURES TO DROP OFF TO LOWS IN THE LOWER TO
MID 20S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 355 AM CDT THU APR 18 2013
FRIDAY MORNING THE UPPER VORTEX WILL BE MOVING INTO THE GREAT
LAKES REGION...WHILE ACROSS OUR REGION...NORTHWEST FLOW WILL BE IN
PLACE ACROSS THE CENTRAL PLAINS. MODELS INDICATE A 80KT JET STREAK
NOSING SOUTHEAST ON THE BACK SIDE OF THE TROUGH FM THE DAKOTAS
FRIDAY IN THE NW FLOW REGIME...WHICH REACHES EAST CENTRAL/EASTERN
NEB FRIDAY AFTN. FORECAST SOUNDINGS INDICATE CONVECTIVE TEMPS IN
THE MID/UPPER 40S...AND AFTN HIGHS ARE FORECAST NEAR THIS AND WITH
INCREASING DYNAMICS WITH SHEARED SHORTWAVE ENERGY AND JET...HAVE
WENT AHEAD AND INCLUDED SPRINKLE POTENTIAL FOR THE AFTN. SREF POPS
ARE FAIRLY HIGH IN THE 30 TO 40 PCNT RANGE...BUT FEEL SPRINKLES
SHOULD COVER THINGS FOR NOW.
DRY CONDITIONS BUT COOL CONDITIONS ARE FORECAST FRIDAY NIGHT WITH
LOWS IN THE UPPER 20S/LOW 30S. THE AIRMASS BEGINS TO MODERATE OVER
THE WEEKEND BEHIND THE DEPARTING UPPER TROUGH. WARM FRONT LIFTS
E/NE ON SATURDAY AND TEMPS SHOULD CLIMB CLOSER TO SEASONAL NORMALS.
A MID LEVEL SHORTWAVE TROUGH AND ASSOCIATED SFC TROUGH/COOL FRONT
TRANSLATE EAST SATURDAY NIGHT BRINGING SLIGHT CHCS FOR PCPN. THE
UPPER WAVE TRANSLATES ACROSS THE PLAINS SUNDAY WITH CONTINUED
CHCS FOR CONVECTION IN UPPER DYNAMICS.
THE WEATHER PATTERN NEXT WEEK REMAINS ACTIVE WITH AN UPPER TROUGH
OVER CANADA SWINGING SOUTH FM THE NORTHERN PLAINS MONDAY NIGHT INTO
TUESDAY. SIMILAR TO THE LAST FEW WEEKS...CONVECTIVE POTENTIAL
EXISTS AHEAD OF THE SYSTEM...WITH AIRMASS PROGGED COLD ENOUGH FOR A
RAIN/SNOW MIX OR MAYBE EVEN A CHANGE TO SNOW FOR SOME AREAS MONDAY
NIGHT. UNSEASONALLY COLD TEMPERATURES WILL RETURN FOR SEVERAL DAYS
TO START THE WORK WEEK WITH CONDITIONS DRYING OUT BEHIND THE TROUGH
TUESDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 547 AM CDT THU APR 18 2013
ANOTHER BAND OF SNOW HAS FORMED AND WILL BE MOVING THROUGH THE KGRI
TERMINAL AREA IN THE NEXT FEW HOURS. BEHIND THIS BAND THERE WILL
BE IMPROVING CONDITIONS THROUGH EARLY IN THE AFTERNOON. DURING THE
EVENING CLOUDS WILL START TO DECREASE AND VFR CONDITIONS WILL BE
FOUND LATE THIS AFTERNOON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR
NEZ039>041-046>049-060>064-072>076-082>085.
KS...NONE.
&&
$$
UPDATE...BRYANT
SHORT TERM...JCB
LONG TERM...FAY
AVIATION...JCB
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
126 PM EDT THU APR 18 2013
.SYNOPSIS...
A WARM FRONT WILL APPROACH THE REGION TODAY...AND THEN MOVE NORTH
INTO CANADA TONIGHT. IT WILL BE WARM AND BECOMING WINDY TODAY AND
FRIDAY AS GUSTY SOUTHERLY WINDS WILL BRING MUCH WARMER AIR TO THE
NORTH COUNTRY...WITH HIGHS IN THE 70S ON FRIDAY. A COLD FRONT WILL
MOVE INTO THE REGION LATE FRIDAY AFTERNOON AND THEN MOVE ACROSS
THE AREA FRIDAY NIGHT...BRINGING RAIN SHOWERS TO THE NORTH
COUNTRY. IT WILL BE MUCH COOLER AND BREEZY ON SATURDAY. A HIGH
PRESSURE AREA OVER THE GREAT LAKES WILL BUILD INTO THE REGION
SATURDAY NIGHT AND SUNDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 121 PM EDT THURSDAY...WIND GUSTS NO SIGNIFICANT CHANGES FOR
THIS LATEST UPDATE. AREA OF SHOWERS HAS MOVED THROUGH AND OUT OF
OUR FORECAST AREA.
PREVIOUS DISCUSSION FROM 451 AM EDT THURSDAY...WARM FRONT WILL
LIFT NORTHEAST THROUGH THE REGION TODAY BRINGING CLOUDS...ALONG
WITH A CHANCE OF RAIN SHOWERS MAINLY OVER THE SAINT LAWRENCE
VALLEY AND THE ADIRONDACKS. TEMPERATURES WILL CLIMB TO THE UPPER
50S TO LOWER 60S TODAY. SURFACE PRESSURE GRADIENT TO TIGHTEN THIS
AFTERNOON...SO COULD SEE SOME SOUTHERLY WIND GUSTS UP TO 40 MPH
POSSIBLE THIS AFTERNOON FROM THE CHAMPLAIN VALLEY WESTWARD ACROSS
NORTHERN NEW YORK. MOS POPS LOOK TOO HIGH FOR TODAY...SO HAVE
LOWERED THEM QUITE A BIT.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY/...
AS OF 451 AM EDT THURSDAY...THE WARM FRONT WILL LIFT NORTHEAST
INTO QUEBEC TONIGHT. HAVE GONE WITH A DRY FORECAST FOR TONIGHT...
AS THE BEST LIFT ASSOCIATED WITH THE WARM FRONT WILL BE IN CANADA.
THUS...HAVE GREATLY LOWERED MOS POPS FOR TONIGHT. GUSTY SOUTHERLY
WINDS WILL CONTINUE INTO TONIGHT...AND THIS WILL HELP TO KEEP
TEMPERATURES UP TONIGHT. HAVE GONE SEVERAL DEGREES WARMER THAN THE
GFS MOS GUIDANCE FOR MIN TEMPERATURES TONIGHT. ON FRIDAY...GUSTY
SOUTHERLY WINDS WILL CONTINUE AS SURFACE PRESSURE GRADIENT REMAINS
TIGHT ACROSS THE REGION. SOUTHERLY WIND GUSTS COULD APPROACH 50
MPH FRIDAY AFTERNOON ACROSS WESTERN VERMONT AND NORTHERN NEW YORK.
GIVEN THAT THIS WILL OCCUR LATE IN THE THIRD PERIOD OF THE
FORECAST...HAVE HELD OFF ON ANY WIND ADVISORY AT THIS TIME. WILL
LET LATER SHIFTS REVIEW LATER GUIDANCE BEFORE MAKING ANY DECISION
ON A WIND ADVISORY. HAVE MENTIONED THIS POSSIBILITY IN THE
HAZARDOUS WEATHER OUTLOOK PRODUCT. EXPECTING FRIDAY TO START OUT
AS A MAINLY DRY DAY ACROSS THE REGION WITH TEMPERATURES CLIMBING
INTO THE 70S FRIDAY AFTERNOON. THE BEST CHANCE FOR RAIN SHOWERS
FOR LATER FRIDAY AFTERNOON WILL BE ACROSS THE SAINT LAWRENCE
VALLEY AND THE ADIRONDACKS IN NORTHERN NEW YORK...AS THE COLD
FRONT MOVES INTO THE REGION. HAVE HELD OFF ON BRINGING RAIN
SHOWERS FOR THE CHAMPLAIN VALLEY AND VERMONT UNTIL FRIDAY NIGHT.
MODELS SHOW A MID LEVEL DRY SLOT WILL WORK INTO THE REGION LATE
FRIDAY NIGHT...SO EXPECTING ANY RAIN SHOWER ACTIVITY WILL COME TO
AN END BEFORE DAYBREAK ON SATURDAY. MUCH COOLER TEMPERATURES WILL
BE OVER THE REGION ON SATURDAY. HAVE PUT IN SLIGHT CHANCE POPS
OVER THE MOUNTAINS FOR RAIN SHOWERS ON SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 510 AM EDT THURSDAY...OVERALL GOOD AGREEMENT BTWN GFS/ECMWF
FOR THE WEEKEND AND INTO EARLY NEXT WK...THEN UNCERTAINTY DEVELOPS
AS PATTERN BECMG MORE ACTIVE. SFC HIGH PRES WL RESULT IN MAINLY
CLR SKIES AND DRY CONDITIONS FOR SUNDAY/MONDAY. GIVEN DEEP DRY
AIRMASS ACRS THE NE CONUS...EXPECT LARGE SWINGS IN DIURNAL TEMPS
FROM LOWS SAT NIGHT/SUNDAY NIGHT TO HIGHS ON SUNDAY/MONDAY. TEMPS
WL BE 4 TO 8 DEGREES BLW NORMAL. THE 00Z ECMWF HAS TRENDED TWD THE
GFS/GFS ENSEMBLE AND GEM FOR TUESDAY...WITH TRACK WELL TO OUR
SOUTH AND EAST. GIVEN UNCERTAINTY WITH ANTICYCLONIC FLW AROUND
HIGH PRES AND POTENTIAL FOR SOME MOISTURE TO ADVECT BACK INTO OUR
CENTRAL/EASTERN CWA WL MENTION SCHC/LOW CHC POPS. ALSO...THIS WL
CONT WITH PREVIOUS FCSTER THINKING. OTHERWISE...MODELS ARE IN
RELATIVELY GOOD AGREEMENT WITH NEXT LARGE SCALE SYNOPTIC SYSTEM
IMPACTING OUR REGION LATE WEDS INTO THURS. ONCE AGAIN SFC LOW PRES
WL TRACK TO OUR WEST...PLACING OUR CWA IN THE WARM SECTOR BY WEDS
ALONG CHCS FOR PRECIP WED AFTN INTO THURS. TEMPS WL BE NEAR NORMAL
TUES AND ABOVE NORMAL FOR WEDS INTO THURS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
THROUGH 12Z FRIDAY...DEVELOPING STRONG SOUTHERLY SFC WINDS WILL
CREATE AREAS OF MODERATE TURBULENCE AND AREAS OF POTENTIAL LLVL
WIND SHEAR TODAY. AVIATION CHALLENGE THRU THIS EVENING WL BE
PLACEMENT OF LIGHT RAIN SHOWERS THIS MORNING...FOLLOWED BY GUSTY
WINDS. CRNT SFC ANALYSIS SHOWS HIGH PRES LOCATED OVER NORTHERN NEW
ENGLAND WITH A SFC WARM FRNT LIFTING ACRS NORTHERN NY ATTM. THIS
FRNT AND ASSOCIATED RIBBON OF DEEPER MOISTURE WL LIFT ACRS
NORTHERN NY TAF SITES BTWN 12Z AND 15Z THIS MORNING. BASED OFF THE
RAP 13 HAVE TEMPO A PERIOD OF -SHRA FOR MSS/SLK EARLY THIS
MORNING. WL USE VCSH AT PBG/BTV BTWN 13-16Z. IN ADDITION...SFC
GRADIENT WL INCREASE WITH GUSTY SOUTH WINDS ANTICIPATED. SOUNDINGS
SHOW WIND GUSTS POTENTIAL BTWN 25 AND 30 KNTS THIS AFTN...AS SFC
HEATING OCCURS. RAP SOUNDINGS SHOW GUST POTENTIAL BTWN 35 ADN 40
KNTS AT MSS/BTV/SLK BTWN 19Z AND 02Z TODAY. VFR CONDITIONS WL
PREVAIL THRU TODAY. NAM AND RAP CONTS TO SHOW SOME LLVL RH/CLOUDS
INCREASING THIS EVENING WITH THE POTENTIAL FOR SOME MVFR CIGS IN A
STRATO CUMULUS DECK...NOT ANTICIPATING FOG/BR GIVEN LLVL WIND
PROFILES...WL USE SCATTERED 1200 TO 1500 FT TO SHOW THIS POTENTIAL
OUTLOOK 12Z FRIDAY THROUGH MONDAY... GUSTY SOUTHERLY WINDS WL CONT
ON FRIDAY AS SFC LOW PRES TRACKS FROM THE GREAT LAKES INTO CENTRAL
CANADA. A BROKEN LINE OF SHOWERS WL IMPACT OUR TAF SITES LATE
FRIDAY INTO SATURDAY WITH A BRIEF PERIOD OF MVFR CONDITIONS
POSSIBLE IN THE HEAVIER SHOWERS. OTHERWISE...SFC HIGH PRES AND VFR
CONDITIONS PREVAIL SAT THRU EARLY NEXT WEEK.
&&
.HYDROLOGY...
AS OF 451 AM EDT THURSDAY...WARMER TEMPERATURES TODAY AND FRIDAY
WILL RESULT IN MELTING SNOW ACROSS THE HIGHER ELEVATIONS OF THE
ADIRONDACKS AND GREEN MOUNTAINS. RUNOFF FROM THIS SNOW MELT WILL
LEAD TO SOME SHARP RISES ON AREA RIVERS TODAY THROUGH FRIDAY.
HOWEVER...NO FLOODING IS EXPECTED AT THIS TIME.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH/NEILES
NEAR TERM...WGH/NEILES
SHORT TERM...WGH
LONG TERM...TABER
AVIATION...TABER
HYDROLOGY...WGH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1036 AM EDT THU APR 18 2013
.SYNOPSIS...
A WARM FRONT WILL APPROACH THE REGION TODAY...AND THEN MOVE NORTH
INTO CANADA TONIGHT. IT WILL BE WARM AND BECOMING WINDY TODAY AND
FRIDAY AS GUSTY SOUTHERLY WINDS WILL BRING MUCH WARMER AIR TO THE
NORTH COUNTRY...WITH HIGHS IN THE 70S ON FRIDAY. A COLD FRONT WILL
MOVE INTO THE REGION LATE FRIDAY AFTERNOON AND THEN MOVE ACROSS
THE AREA FRIDAY NIGHT...BRINGING RAIN SHOWERS TO THE NORTH
COUNTRY. IT WILL BE MUCH COOLER AND BREEZY ON SATURDAY. A HIGH
PRESSURE AREA OVER THE GREAT LAKES WILL BUILD INTO THE REGION
SATURDAY NIGHT AND SUNDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 1024 AM EDT THURSDAY...WIND GUSTS THIS AFTERNOON WILL BE
VERY CLOSE TO CRITERIA FOR AN ADVISORY. MAY ISSUE AN ADVISORY WITH
NEXT UPDATE AT 1730Z. INCREASED THE POPS ACROSS THE AREA WITH AREA
OF SHOWERS MOVING ACROSS THE NORTHERN PART OF OUR CWA.
PRECIPITATION WILL BE VERY LIGHT.
PREVIOUS DISCUSSION FROM 451 AM EDT THURSDAY...WARM FRONT WILL
LIFT NORTHEAST THROUGH THE REGION TODAY BRINGING CLOUDS...ALONG
WITH A CHANCE OF RAIN SHOWERS MAINLY OVER THE SAINT LAWRENCE
VALLEY AND THE ADIRONDACKS. TEMPERATURES WILL CLIMB TO THE UPPER
50S TO LOWER 60S TODAY. SURFACE PRESSURE GRADIENT TO TIGHTEN THIS
AFTERNOON...SO COULD SEE SOME SOUTHERLY WIND GUSTS UP TO 40 MPH
POSSIBLE THIS AFTERNOON FROM THE CHAMPLAIN VALLEY WESTWARD ACROSS
NORTHERN NEW YORK. MOS POPS LOOK TOO HIGH FOR TODAY...SO HAVE
LOWERED THEM QUITE A BIT.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY/...
AS OF 451 AM EDT THURSDAY...THE WARM FRONT WILL LIFT NORTHEAST
INTO QUEBEC TONIGHT. HAVE GONE WITH A DRY FORECAST FOR TONIGHT...
AS THE BEST LIFT ASSOCIATED WITH THE WARM FRONT WILL BE IN CANADA.
THUS...HAVE GREATLY LOWERED MOS POPS FOR TONIGHT. GUSTY SOUTHERLY
WINDS WILL CONTINUE INTO TONIGHT...AND THIS WILL HELP TO KEEP
TEMPERATURES UP TONIGHT. HAVE GONE SEVERAL DEGREES WARMER THAN THE
GFS MOS GUIDANCE FOR MIN TEMPERATURES TONIGHT. ON FRIDAY...GUSTY
SOUTHERLY WINDS WILL CONTINUE AS SURFACE PRESSURE GRADIENT REMAINS
TIGHT ACROSS THE REGION. SOUTHERLY WIND GUSTS COULD APPROACH 50
MPH FRIDAY AFTERNOON ACROSS WESTERN VERMONT AND NORTHERN NEW YORK.
GIVEN THAT THIS WILL OCCUR LATE IN THE THIRD PERIOD OF THE
FORECAST...HAVE HELD OFF ON ANY WIND ADVISORY AT THIS TIME. WILL
LET LATER SHIFTS REVIEW LATER GUIDANCE BEFORE MAKING ANY DECISION
ON A WIND ADVISORY. HAVE MENTIONED THIS POSSIBILITY IN THE
HAZARDOUS WEATHER OUTLOOK PRODUCT. EXPECTING FRIDAY TO START OUT
AS A MAINLY DRY DAY ACROSS THE REGION WITH TEMPERATURES CLIMBING
INTO THE 70S FRIDAY AFTERNOON. THE BEST CHANCE FOR RAIN SHOWERS
FOR LATER FRIDAY AFTERNOON WILL BE ACROSS THE SAINT LAWRENCE
VALLEY AND THE ADIRONDACKS IN NORTHERN NEW YORK...AS THE COLD
FRONT MOVES INTO THE REGION. HAVE HELD OFF ON BRINGING RAIN
SHOWERS FOR THE CHAMPLAIN VALLEY AND VERMONT UNTIL FRIDAY NIGHT.
MODELS SHOW A MID LEVEL DRY SLOT WILL WORK INTO THE REGION LATE
FRIDAY NIGHT...SO EXPECTING ANY RAIN SHOWER ACTIVITY WILL COME TO
AN END BEFORE DAYBREAK ON SATURDAY. MUCH COOLER TEMPERATURES WILL
BE OVER THE REGION ON SATURDAY. HAVE PUT IN SLIGHT CHANCE POPS
OVER THE MOUNTAINS FOR RAIN SHOWERS ON SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 510 AM EDT THURSDAY...OVERALL GOOD AGREEMENT BTWN GFS/ECMWF
FOR THE WEEKEND AND INTO EARLY NEXT WK...THEN UNCERTAINTY DEVELOPS
AS PATTERN BECMG MORE ACTIVE. SFC HIGH PRES WL RESULT IN MAINLY
CLR SKIES AND DRY CONDITIONS FOR SUNDAY/MONDAY. GIVEN DEEP DRY
AIRMASS ACRS THE NE CONUS...EXPECT LARGE SWINGS IN DIURNAL TEMPS
FROM LOWS SAT NIGHT/SUNDAY NIGHT TO HIGHS ON SUNDAY/MONDAY. TEMPS
WL BE 4 TO 8 DEGREES BLW NORMAL. THE 00Z ECMWF HAS TRENDED TWD THE
GFS/GFS ENSEMBLE AND GEM FOR TUESDAY...WITH TRACK WELL TO OUR
SOUTH AND EAST. GIVEN UNCERTAINTY WITH ANTICYCLONIC FLW AROUND
HIGH PRES AND POTENTIAL FOR SOME MOISTURE TO ADVECT BACK INTO OUR
CENTRAL/EASTERN CWA WL MENTION SCHC/LOW CHC POPS. ALSO...THIS WL
CONT WITH PREVIOUS FCSTER THINKING. OTHERWISE...MODELS ARE IN
RELATIVELY GOOD AGREEMENT WITH NEXT LARGE SCALE SYNOPTIC SYSTEM
IMPACTING OUR REGION LATE WEDS INTO THURS. ONCE AGAIN SFC LOW PRES
WL TRACK TO OUR WEST...PLACING OUR CWA IN THE WARM SECTOR BY WEDS
ALONG CHCS FOR PRECIP WED AFTN INTO THURS. TEMPS WL BE NEAR NORMAL
TUES AND ABOVE NORMAL FOR WEDS INTO THURS.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
THROUGH 12Z FRIDAY...DEVELOPING STRONG SOUTHERLY SFC WINDS WILL
CREATE AREAS OF MODERATE TURBULENCE AND AREAS OF POTENTIAL LLVL
WIND SHEAR TODAY. AVIATION CHALLENGE THRU THIS EVENING WL BE
PLACEMENT OF LIGHT RAIN SHOWERS THIS MORNING...FOLLOWED BY GUSTY
WINDS. CRNT SFC ANALYSIS SHOWS HIGH PRES LOCATED OVER NORTHERN NEW
ENGLAND WITH A SFC WARM FRNT LIFTING ACRS NORTHERN NY ATTM. THIS
FRNT AND ASSOCIATED RIBBON OF DEEPER MOISTURE WL LIFT ACRS
NORTHERN NY TAF SITES BTWN 12Z AND 15Z THIS MORNING. BASED OFF THE
RAP 13 HAVE TEMPO A PERIOD OF -SHRA FOR MSS/SLK EARLY THIS
MORNING. WL USE VCSH AT PBG/BTV BTWN 13-16Z. IN ADDITION...SFC
GRADIENT WL INCREASE WITH GUSTY SOUTH WINDS ANTICIPATED. SOUNDINGS
SHOW WIND GUSTS POTENTIAL BTWN 25 AND 30 KNTS THIS AFTN...AS SFC
HEATING OCCURS. RAP SOUNDINGS SHOW GUST POTENTIAL BTWN 35 ADN 40
KNTS AT MSS/BTV/SLK BTWN 19Z AND 02Z TODAY. VFR CONDITIONS WL
PREVAIL THRU TODAY. NAM AND RAP CONTS TO SHOW SOME LLVL RH/CLOUDS
INCREASING THIS EVENING WITH THE POTENTIAL FOR SOME MVFR CIGS IN A
STRATO CUMULUS DECK...NOT ANTICIPATING FOG/BR GIVEN LLVL WIND
PROFILES...WL USE SCATTERED 1200 TO 1500 FT TO SHOW THIS POTENTIAL
OUTLOOK 12Z FRIDAY THROUGH MONDAY... GUSTY SOUTHERLY WINDS WL CONT
ON FRIDAY AS SFC LOW PRES TRACKS FROM THE GREAT LAKES INTO CENTRAL
CANADA. A BROKEN LINE OF SHOWERS WL IMPACT OUR TAF SITES LATE
FRIDAY INTO SATURDAY WITH A BRIEF PERIOD OF MVFR CONDITIONS
POSSIBLE IN THE HEAVIER SHOWERS. OTHERWISE...SFC HIGH PRES AND VFR
CONDITIONS PREVAIL SAT THRU EARLY NEXT WEEK.
&&
.HYDROLOGY...
AS OF 451 AM EDT THURSDAY...WARMER TEMPERATURES TODAY AND FRIDAY
WILL RESULT IN MELTING SNOW ACROSS THE HIGHER ELEVATIONS OF THE
ADIRONDACKS AND GREEN MOUNTAINS. RUNOFF FROM THIS SNOW MELT WILL
LEAD TO SOME SHARP RISES ON AREA RIVERS TODAY THROUGH FRIDAY.
HOWEVER...NO FLOODING IS EXPECTED AT THIS TIME.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH/NEILES
NEAR TERM...WGH/NEILES
SHORT TERM...WGH
LONG TERM...TABER
AVIATION...TABER
HYDROLOGY...WGH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
652 AM EDT THU APR 18 2013
.SYNOPSIS...
A WARM FRONT WILL MOVE THROUGH THE REGION TODAY...BRINGING
MILDER TEMPERATURES THROUGH FRIDAY. A STRONG COLD FRONT IS
EXPECTED TO CROSS THE AREA FRIDAY EVENING ACCOMPANIED BY
SHOWERS...AND A CHANCE OF THUNDERSTORMS. COOLER TEMPERATURES WILL
FOLLOW AGAIN THIS WEEKEND UNDER FAIR SKIES.
&&
.NEAR TERM /THROUGH TONIGHT/...
SHORT TERM GUIDANCE FROM THE NAM/GFS/WRF AND RAP MODELS ARE IN
GOOD AGREEMENT TODAY...AND SUGGEST A MILD SURGE OF AIR
OVERSPREADING THE REGION ASSOCIATED WITH A WARM FRONTAL PASSAGE
ALOFT. LOW LEVEL MOISTURE NOTED WITHIN A MARINE LAYER EXTENDING
NORTHWARD FROM THE MID-ATLANTIC STATES WILL MARR THE MILD FORECAST
WITH AN ABUNDANCE OF CLOUDS TODAY. PREVIOUS FORECAST INCLUDED
PATCHY DRIZZLE...HOWEVER THE ISENTROPIC LIFT ASSOCIATED WITH THE
WARM FRONTAL BOUNDARY LOOKS TO BE FOCUSED WELL TO OUR NORTH ALONG
THE 850 MB FRONTAL ZONE. THIS LEAVES MAINLY OROGRAPHIC EFFECTS TO
SQUEEZE OUT ANY LIGHT PRECIP. THIS IS NOT TYPICALLY FAVORABLE
DURING THE WELL MIXED DAYLIGHT HOURS...AND WE EXPECT CLOUD
CEILINGS TO BE MODESTLY HIGH TODAY AND NOT CONDUCIVE TO DRIZZLE.
DECIDED TO REMOVE MENTION OF PTCHY DRIZZLE FOR TODAY.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
THE SOUTH-SOUTHEASTERLY FLOW IMPINGING ON OUR HIGHER TERRAIN
TONIGHT...ALONG WITH BOUNDARY LAYER COOLING AND SATURATION SEEMS
TO OFFER THE BETTER OPPORTUNITY FOR DRIZZLE AFTER DARK. WILL KEEP
THAT IN THE FORECAST ACROSS THE SOUTHERN TIER NY AND NEPA...AND
REFINE THE FORECAST TO FEATURE DRIZZLE MAINLY OVER THE ELEVATIONS
ABOVE 1200-1500 FEET.
THE MORE INTERESTING PART OF THE FORECAST OCCURS LATER FRIDAY
AFTERNOON AS THE MAIN COLD FRONT OF THE APPROACHING STORM SYSTEM
CROSSES THE REGION. MODEL SOLUTIONS ARE CONSISTENT AND MAINTAIN
THAT THE BULK OF RAIN ACTIVITY WILL BE BETWEEN ABOUT 21Z AND 02Z.
FORECAST WIND PROFILES ARE IMPRESSIVE BOTH IN SPEED AND DIRECTIONAL
SHEAR...BUT INSTABILITY IS WEAK WITHIN A MODERATELY MOIST ADIABATIC
ENVIRONMENT. A FEW HUNDRED J/KG OF CAPE IS ENOUGH TO WARRANT
MENTION OF THUNDER...BUT A SVR THREAT AT THIS TIME SEEMS LOW WITH
THE EXPECTATION OF AN ABUNDANCE OF LOW CLOUD COVER LIMITING THE DIURNAL
HEATING. THE SPC INDICATES GENERAL THUNDER FOR THE REGION BUT NO
MENTION OF SVR. GRADIENT SYNOPTIC WINDS DO LOOK BLUSTERY IN THE
15-30 MPH RANGE...BUT AT THIS TIME SHOULD REMAIN SAFELY UNDER ANY
KIND OF IMPACT THRESHOLDS.
FRONTAL PASSAGE FRIDAY EVENING WILL USHER A GOOD SHOT OF RAIN AND
THEN SOME MARKEDLY COLDER AIR HEADING INTO THE WEEKEND WITH
OVERNIGHT TEMPS IN THE 30S AND A REBOUND ON SATURDAY ONLY INTO THE 40S.
AM NOT TOO EXCITED ABOUT ANY LAKE RESPONSE...HOWEVER COLD
ADVECTION CLOUDINESS IS EXPECTED INTO SATURDAY MORNING DESPITE
SOME PRONOUNCED DRYING IN THE 1000-500 MB MEAN RH LAYER DEPICTED
BY THE MODELS. HIGH PRESSURE BUILDS IN QUICKLY FOR SATURDAY WITH
IMPROVING CONDITIONS AND EVENTUALLY CLEARING SKIES HEADING INTO
SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
300 AM UPDATE...LATEST GFS/ECMWF, SHOWS THE ECMWF IN BETTER
AGREEMENT WITH THE GFS, INDICATING A WEAKER AND FARTHER OUT TO
SEA SFC LOW ALONG THE EAST COAST TUE/WED. CURRENT EXTENDED IN
GOOD SHAPE, WILL CONTINUE WITH CHC/SLIGHT CHC POPS TUE THROUGH
WEDNESDAY.
PREVIOUS DISC...
A FAIRLY QUIET PERIOD SHAPING UP FOR THE FIRST HALF OF THE
EXTENDED PERIOD AS HIGH PRESSURE QUICKLY BUILDS IN FOLLOWING THE EARLY
WEEKEND COLD FRONT. WITH ITS ARRIVAL...COOLER AIR WILL BE IN STORE
WITH HIGHS ONLY EXPECTED TO WARM INTO THE UPPER 40S TO LOWER 50S
ON SUNDAY. NEXT WX FEATURE OF INTEREST WILL BE A NORTHWARD LIFTING
AREA OF LOW PRESSURE ALONG THE EASTERN SEABOARD WHICH THE ECMWF
SHOWS MOVING INTO THE AREA SOMETIME DURING THE DAY ON TUESDAY. THE
GFS ON THE OTHER HAND KEEPS THIS FEATURE WELL OFFSHORE WITH LITTLE
TO NO IMPACT ON OUR AREA. FOR NOW...WILL MAINTAIN SLGT CHC TO CHC
MENTION FOR OUR FCST AREA BEGINNING TUE WITH THIS TREND CONTINUING
THROUGH THE CONCLUSION OF THE PERIOD AS BOTH THE GFS AND ECMWF
SHOW THE NEXT WX SYSTEM/COLD FRONT APPROACHING FROM THE WEST BY
MIDWEEK. NO SIGNIFICANT DEVIATIONS FROM HPC GUIDANCE.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
A SFC WARM FRONT SOUTH OF THE REGION WILL LIFT NORTH THROUGH THE
AREA LATER TODAY AND THIS EVENING. MOISTURE FROM THIS BOUNDARY
AND INCREASING SOUTHEAST FLOW WILL LOWER CIGS TO AROUND 4K FT
THIS MORNING. LIGHT SHOWERS ARE POSSIBLE AT KRME/KSYR THROUGH
14Z. CIGS WILL REMAIN AROUND THIS HEIGHT THROUGH THE DAY. THIS
EVENING CIGS WILL LOWER INTO THE MVFR/LOW MVFR CATEGORY WITH
DRIZZLE LIKELY LATER TONIGHT AT KAVP.
E/SE WINDS AROUND 10 KNOTS BECOMING S/SE LATER THIS MORNING AT
12-18 KNOTS WITH GUSTS AROUND 25 KNOTS. S/SE WINDS OVERNIGHT AT
10-15 KNOTS.
.OUTLOOK...
FRI/FRI NGT...MVFR RESTRICTIONS POSSIBLE BY AFTERNOON IN SHRA-
TSRA.
SAT THROUGH MON...VFR UNDER HIGH PRESSURE.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...MLJ/PVN
SHORT TERM...MLJ
LONG TERM...CMG/RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS RALEIGH NC
125 PM EDT THU APR 18 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED OFF THE NEW ENGLAND COAST WILL EXTEND DOWN
THE EAST COAST TODAY. A STRONG COLD FRONT WILL APPROACH FROM THE
WEST TONIGHT... AND CROSS THE REGION FRIDAY AFTERNOON THROUGH FRIDAY
NIGHT. COOL HIGH PRESSURE WILL BUILD IN FROM THE WEST ON SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 945 AM THURSDAY...
TODAY:
A WEAKENING MID-LEVEL SHORTWAVE UNDER THE WEST SIDE OF THE BROAD
UPPER RIDGE WILL CONTINUE TO LIFT NORTHEAST TODAY. AS OF MID MORNING
CENTRAL NORTH CAROLINA WAS UNDER A SURFACE THETA-E MINIMUM...AND
WHILE THE 12Z KGSO SOUNDING SHOWED A VERY MOIST LAYER BETWEEN ABOUT
900MB AND 650MB WITH THE LAPSE RATE GREATER THAN MOIST ADIABATIC...
DURING THE DAY BOTH THE GFS AND THE NAM FORECAST WARMING AND DRYING
IN THAT LAYER. THIS SHOULD BE ENOUGH TO CAP THE ATMOSPHERE TO DEEP
CONVECTION. THE RUC...GFS...AND THE NAM ALL SHOW NO QPF IN CENTRAL
NORTH CAROLINA THIS AFTERNOON...AND THE HRRR WRF...ASIDE FROM WHAT
APPEAR TO BE SOME SPOTTY CU...SEEMS ALSO TO BE VERY LIMITED WITH
DEEP CONVECTION. WILL KEEP CHANCES FOR PRECIPITATION BELOW SLIGHT
CHANCE THROUGH THE AFTERNOON...AND WITH THE SHORTWAVE THERE WILL BE
AREAS OF CLOUDS THAT SHOULD GRADUALLY MIX AND BECOME INCREASINGLY
SCATTERED WITH TIME. UNDER AN OVERALL PARTLY SUNNY SKY...1000-850MB
THICKNESSES SUPPORT MAXES FROM AROUND 80 TO THE LOWER 80S...IN
CONCERT WITH MOS GUIDANCE. MIXING SHOULD PROVIDE FOR SOME WIND GUSTS
IN THE UPPER TEENS KNOTS AND A FEW LOWER 20S KNOTS AT TIMES
PARTICULARLY FROM AROUND NOON THROUGH THE MIDDLE OF THE AFTERNOON.
-DJF
TONIGHT:
STRENGTHENING SOUTHERLY MOISTURE TRANSPORT WITH THE APPROACH OF THE
AMPLIFIED UPPER TROUGH AND ATTENDANT SURFACE COLD FRONT INTO THE TN
VALLEY WILL LIKELY SUPPORT WIDESPREAD LOW CLOUDS INTO THE AREA
AFTER MIDNIGHT WITH SPOTTY WAA SHOWERS OVERSPREADING THE AREA FROM
OFF THE ATLANTIC/SOUTHEAST COAST. LOWS IN THE LOWER 60S. -CBL
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 250 AM THURSDAY...
A DEAMPLIFYING UPPER TROUGH WILL CONTINUE TO MOVE EAST THROUGHOUT
THE DAY ON FRIDAY...WITH THE PARENT SURFACE LOW MOVING WELL NORTH OF
THE AREA ACROSS THE GREAT LAKES/CANADA. THE TRAILING COLD FRONT WILL
CROSS OUR AREA FRIDAY/FRIDAY NIGHT WITH AN ACCOMPANYING LINE OF
SHOWERS AND THUNDERSTORMS. WITH THE BEST FORCING MOVING NORTH OF THE
REGION...THE MAIN CONCERN CONTINUES TO BE THE POTENTIAL FOR SEVERE
WEATHER. MODELS ARE IN GOOD AGREEMENT WITH THE LINE OF SHOWERS AND
THUNDERSTORMS MOVING ACROSS CENTRAL NC FROM WEST TO EAST FRIDAY
AFTERNOON THROUGH EARLY SATURDAY MORNING. AS IS COMMONLY THE
CASE...PLENTY OF SHEAR WILL BE IN PLACE...AS WELL AS DECENT LOW
LEVEL LAPSE RATES AS TEMPS ARE EXPECTED TO RISE INTO THE UPPER
70S/LOWER 80S...BUT THE AMOUNT OF INSTABILITY WILL BE THE MAIN
LIMITING FACTOR. MODELS CONTINUE TO PROG ONLY MARGINAL
INSTABILITY...LIKELY DUE TO THE EXTENSIVE CLOUD COVER EXPECTED AHEAD
OF THE APPROACHING FRONT...AS WELL AS THE SOMEWHAT NOCTURNAL TIMING
OF THE PRECIP (THIS SECOND POINT WILL MOSTLY COME INTO PLAY FOR THE
EASTERN PORTIONS OF THE FORECAST AREA). THE SPC DECIDED NOT TO
UPGRADE THE AREA TO A DAY 2 SLIGHT RISK FOR NOW...MAINLY DUE TO
POTENTIAL OF LIMITED INSTABILITY... ALTHOUGH THEY POINTED OUT THAT
IF ENOUGH DESTABILIZATION DOES OCCUR...A SLIGHT RISK MAY EVENTUALLY
BE NEEDED. NEVERTHELESS...WILL CONTINUE TO MENTION THE POSSIBILITY
OF STRONG TO SEVERE STORMS...WITH THE PRIMARY THREAT BEING DAMAGING
WIND...IN THE HWO. PRECIP IS EXPECTED TO COME TO AN END FROM WEST TO
EAST SATURDAY MORNING...WITH HIGH PRESSURE BUILDING IN FOR SATURDAY
NIGHT.
HIGHS ON FRIDAY ARE EXPECTED TO RANGE FROM THE UPPER 70S ACROSS THE
WEST TO LOW/MID 80S FURTHER EAST. OVERNIGHT LOWS ON FRIDAY NIGHT
WILL BE DEPENDENT ON THE TIMING OF THE EXITING PRECIP AND
COMMENCEMENT OF COLD AIR ADVECTION. AT THIS TIME...IT APPEARS PRECIP
SHOULD CLEAR OUT OF AT LEAST THE WESTERN PORTIONS OF THE FORECAST
AREA BEFORE DAYBREAK AND THEREFORE AM EXPECTING TEMPS TO RANGE FROM
THE UPPER 40S/LOWER 50S ACROSS THE WEST TO MID/UPPER 50S FURTHER
EAST. CONDITIONS WILL IMPROVE THROUGHOUT THE DAY ON SATURDAY AND
WITH COLD AIR ADVECTION PERSISTING...HIGHS SHOULD GENERALLY BE IN
THE MID/UPPER 60S. OVERNIGHT LOWS ARE EXPECTED TO FALL INTO THE 40S
AREAWIDE SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 320 AM THURSDAY...
COOL AND DRY CONDITIONS TO CLOSE THE WEEKEND AS A BROAD LONG WAVE
TROUGH WILL ENCOMPASS MUCH OF THE CONUS WITH A STRONG MIGRATORY
CANADIAN SURFACE HIGH BUILDING OVER THE NE US AND MID-ATLANTIC
REGION BEFORE QUICKLY SHIFTING OFF THE NEW ENGLAND COAST.
A BIT OF UNCERTAINTY BEGINS TO CREEP INTO THE PICTURE OWING TO
NORTHERN STREAM AMPLIFICATION OVER THE ROCKIES AND INTO THE CENTRAL
US EARLY NEXT WEEK. IN RESPONSE TO THE DIGGING TROUGH...MODELS SHOW
WEAK CYCLOGENESIS ALONG THE STALLED BAROCLINIC FRONTAL ZONE OFF THE
SOUTHEAST COAST WITH A POTENTIAL FOR ANOTHER HYBRID CAD EVENT EITHER
MONDAY OR TUESDAY PENDING THE EVOLUTION OF THE SYSTEM(STRENGTH AND
LOCATION OF THE COASTAL WAVE). THIS SCENARIO WOULD ONLY ENHANCE THE
PERIOD OF BELOW NORMAL TEMPERATURES WITH THE POTENTIAL FOR THE RAIN
AND ASSOCIATED WET BULB COOLING TO KEEP DAYTIME HIGHS IN THE LOWER
50S IF THE WETTER SOLUTIONS VERIFY. HAVE PLENTY TIME TO SIT AND WAIT
FOR MODEL DIFFERENCES TO IRON THEMSELVES OUT BEFORE FORECASTING SUCH
A DRASTIC CHANGE...BUT THE POTENTIAL IS DEFINITELY THERE GIVEN SUCH
A STRONG 1040MB CANADIAN SURFACE HIGH OFF THE NEW ENGLAND COAST. THE
LINGERING WEDGE PATTERN LEFT BEHIND WILL ATTEMPT TO ERODE BEFORE
THE AFOREMENTIONED TROUGH AND ATTENDANT SFC COLD FRONT APPROACH THE
AREA FROM THE WEST ON WEDNESDAY/THURSDAY BRINGING WIDESPREAD SHOWERS
AND POSSIBLY THE THREAT OF STORMS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 125 PM THURSDAY...
24 HOUR TAF PERIOD: HIGH CONFIDENCE OF SUB-VFR CONDITIONS OVERNIGHT
THURSDAY INTO FRIDAY MORNING.
FOR THE REMAINDER OF THE DAY TODAY EXPECT SCATTERED TO BROKEN MID
LEVEL CEILINGS TO BEGIN TO ERODE LATER THIS AFTERNOON WITH SCATTERED
CUMULUS LEFT IN PLACE. SOUTH SOUTHEASTERLY WINDS WILL PREVAIL
THROUGH THE EVENING AND WILL REMAIN IN THE 5-10 KNOT RANGE GUSTING
TO 20 KNOTS. OVERNIGHT WINDS WILL REMAIN SOUTHERLY BUT MAY INCREASE
TO 10-15 KNOTS SUSTAINED ESPECIALLY AT NORTHERN AND WESTERN
TERMINALS. FURTHER SOUTH AND EAST EXPECT 5-10 KNOTS TO HOLD THROUGH
THE NIGHT. AFTER 6Z CEILINGS ARE EXPECTED TO DROP TO IFR LEVELS AND
WOULD NOT BE SURPRISED TO SEE LIFR AT TIMES. CONDITIONS SHOULD
IMPROVE A FEW HOURS AFTER SUNRISE BUT MAY VERY WELL STAY IN THE MVFR
RANGE UNTIL LATER IN THE AFTERNOON. AS SKIES BREAK OUT AND MIXING
BEGINS WINDS WILL BE NEAR 15 KNOTS GUSTING TO 20-25 KNOTS ON FRIDAY
WITH THE OCCASIONAL GUST TO 30 KNOTS POSSIBLE. WINDS WILL TAKE ON A
MORE SOUTHWESTERLY DIRECTION BY THE END OF THE TAF PERIOD.
LONG TERM: A STRONG FRONTAL SYSTEM IS EXPECTED TO CROSS THE AREA
FRIDAY NIGHT. STRONG TO POTENTIALLY SEVERE THUNDERSTORMS WILL BE
POSSIBLE WITH THIS SYSTEM. HEAVY RAIN IS ALSO EXPECTED. BEYOND
FRIDAY...INTERMITTENT PERIODS OF SUB-VFR CONDITIONS WILL BE POSSIBLE
THROUGH TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GIH
NEAR TERM...DJF/CBL
SHORT TERM...KRR
LONG TERM...CBL
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
105 PM CDT THU APR 18 2013
.UPDATE...
ISSUED AT 105 PM CDT THU APR 18 2013
EARLY AFTERNOON UPDATE FOCUSES ON SNOW IN THE SOUTHEAST AND CLEARING
SKIES IN THE NORTHWEST. WITH CLEARING AND DECREASING ECHOES ON
RADAR...WILL REMOVE SARGENT COUNTY FROM ADVISORY BUT RETAIN SOME
LIGHT SNOW IN THE REGION. THERE WILL BE A TIGHT QPF GRADIENT
ORIENTED ALONG THE BORDER OF THE DLH AND MPX CWAS...WITH MY AREA ON
THE DRIER SIDE. BOTH GFS AND NAM CONDENSATION PRESSURE DEFICITS
DECREASE RAPIDLY THIS AFTN...NEARING 10+ VALUES BY 00Z. THINK
SNOWFALL MAY TAPER OFF A BIT QUICKER...BUT THERE WILL ALSO BE A
TIGHT GRADIENT WITH THE MAIN PRECIP SHIELD OVER THE MPX AREA. FOR
THIS REASON...WILL LIKELY EXTEND THE ADVISORY FOR MY FAR
SOUTHEASTERN COUNTIES...REMOVE RICHLAND COUNTY...AND POSSIBLY REMOVE
WILKIN DEPENDING ON HOW THINGS LOOK NEARER THE 21Z FCST ISSUANCE
TIME. IN GRANT...OTTER TAIL AND SOUTHERN WADENA COUNTIES
(SPECIFICALLY THE FAR SOUTHERN PORTIONS OF THOSE COUNTIES)...MAY BE
CLOSER TO 5 INCHES OF SNOW WITH 3 TO 5 AVERAGE ACROSS THOSE
COUNTIES. THIS IS MAINLY DUE TO BRINGING HIGHER QPF VALUES A BIT
FURTHER NORTH IN LINE WITH THE RUC GUIDANCE. WILL ADDRESS FURTHER
DETAILS AT 21Z.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 357 AM CDT THU APR 18 2013
WATER VAPOR LOOP INDICATED UPPER LEVEL TROUGH AXIS EXTENDED FROM
WESTERN ND TO THE FOUR CORNERS REGION. UPPER LEVEL TROUGH AXIS TO
MOVE EAST OF THE AREA BY LATE AFTERNOON OR EARLY EVENING. JET
STREAKS WERE MOVING THROUGH THE FLOW AND EXPECT THE NEXT JET STREAK/
SHORT WAVE TO MOVE THROUGH LATER THIS MORNING.
NOT MUCH CHANGE IN THE POPS FOR TODAY AND TONIGHT. RADAR/SURFACE OBS
INDICATING LIGHT SNOW OVER THE CENTRAL RED RIVER VALLEY.
PRECIPITATION WAS DISSIPATING AS PRECIPITATION MOVES NORTHEAST AT 25
TO 30 KNOTS. WILL KEEP WINTER WEATHER ADVISORY GOING IN THE
SOUTHEAST ZONES FOR TODAY...THOUGH IT MAY BE MARGINAL.
ANOTHER JET STREAK/SHORT WAVE OVER NORTHERN ALTA WILL MOVE ACROSS
THE AREA THU NIGHT. PRECIPITATION WITH SHORT WAVE EXPECTED TO STAY
WEST OF THE FORECAST AREA.
UPPER LOW FORECAST TO CLOSE OFF ON FRI AND SURFACE LOW TO DEVELOP.
SURFACE LOW OVER MO TO MOVE NORTHEAST AND TO BEGIN DEEPENING THIS
AFTERNOON THROUGH FRI. NORTH SURFACE WIND EXPECTED TO INCREASE
MAINLY OVER EASTERN ZONES TODAY THROUGH FRI MORNING.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 357 AM CDT THU APR 18 2013
ANOTHER SHORT WAVE IN THE EASTERN PACIFIC WILL MOVE THROUGH SAT
AFTERNOON AND SAT NIGHT. WILL INCREASE POPS FOR THESE TIME PERIODS.
TEMPS FORECAST TO BE ABOVE FREEZING IN THE SOUTHERN ZONES. WILL ADD
THREAT OF RAIN OR SNOW IN THE SOUTH.
MIXED PRECIPITATION (DIURNALLY DRIVEN) SUNDAY SHOULD BEGIN TO PUSH
EAST OF THE NORTHERN PLAINS SUNDAY NIGHT/EARLY MONDAY TO BE
FOLLOWED BY A RELATIVELY DRY FIRST HALF OF THE NEW WEEK. 00Z
ECMWF/GFS AGREE ON LONG WAVE PROGRESSIVE TROUGH EAST OF REGION WITH
ZONAL FLOW BECOMING NORTH TO NORTHWEST...BUT WITH FLOW ORIGINATING
FROM PACIFIC NORTHWEST. ECMWF IS BONE DRY WITH HIGH PRESSURE
DOMINATING MON THROUGH WED...SEEMINGLY OVERDONE ALBEIT SLIGHT CHANCE
POPS PERSIST WITH THE GFS MOST OF THE PERIOD.
GOOD NEWS LIES WITH THE THERMAL FIELDS...SUBZERO 925 MB TEMPS
FINALLY LURCH ABOVE FREEZING BY WEDNESDAY...WITH VAST IMPROVEMENT AT
THE 850 MB LEVEL AS WELL. THIS WILL BOLSTER SURFACE TEMPERATURES
FROM THE LOW 40S LATE WEEKEND TO AROUND 50 BY MID WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 105 PM CDT THU APR 18 2013
THERE WILL BE A BATTLE BETWEEN DRY AIR TO THE NORTH AND MOIST AIR TO
THE SOUTH...WHICH CAN BE SEEN ON SATELLITE IMAGERY. KFAR AND KBJI
WILL BE THE SITES THAT WILL BE IFR/MVFR INTO THE NIGHTTIME
HOURS...WITH KBJI LIKELY IFR/MVFR INTO FRIDAY MORNING. STRONG
NORTHERLY WINDS WILL SUBSIDE A BIT OVERNIGHT...BUT REMAIN BREEZY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR NDZ053.
MN...WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MNZ024-
028>032-040.
&&
$$
UPDATE...SPEICHER
SHORT TERM...HOPPES
LONG TERM...HOPPES/WJB
AVIATION...TG
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1107 AM CDT THU APR 18 2013
.UPDATE...
ISSUED AT 1107 AM CDT THU APR 18 2013
WELL FOR NOW...WE WILL LEAVE HEADLINES ALONE. UNSTABLE BANDED
SNOWFALL IS OCCURRING ACROSS THE SIOUX FALLS FORECAST AREA...AND
WILL BE SLOW TO DIMINISH. HOWEVER FROM I 29 AND POINTS
WESTWARD...MOST OF THE ACCUMULATING SNOW WILL LIKELY FALL THROUGH
MID AFTERNOON...LINGERING 3 OR 4 HOURS LONGER EAST OF I 29.
SNOWFALL MEASUREMENTS COULD BE QUITE VARIABLE ACROSS THIS AREA DUE
TO THE BANDED NATURE OF THE SNOW...A RATHER TYPICAL SPRING SYSTEM.
SO PINNING DOWN EXACT SNOW AMOUNTS IS REALLY TOUGH FOR ANY ONE
POINT LOCATION. THE SNOW WILL BE THE LAST TO EXIT OUR SOUTHWEST MN
ZONES WHICH WILL BE TOWARD MIDNIGHT. THEREFORE WILL NOT ALTER THE
WARNING AREA. CONCERNING THE WIND...VISIBILITIES ARE QUITE
HORRENDOUS IN THE HEAVIER BANDS OF SNOW IN THE COUNTRY. THAT SAID...
MUCH OF THE SNOW IS MELTING ON CONTACT ON WELL TRAVELED PAVEMENT...AND
WILL CONTINUE TO DO SO FOR THE DAY HOURS. AM WORRIED THAT THIS
EVENING THOUGH...THAT BLOWING SNOW ACROSS UNTREATED ROADWAYS WILL
BEGIN TO FREEZE. ONE LAST NOTE...WE WILL PROBABLY BE ABLE TO
CANCEL THE ADVISORY IN SOME OF OUR WESTERN ZONES WITH THE 4 PM
PACKAGE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 420 AM CDT THU APR 18 2013
UPPER LEVEL SUPPORT RAPIDLY EXPANDING NORTHWARD THIS MORNING AND
WILL MAXIMIZE OVER SOUTHEAST SOUTH DAKOTA INTO NORTHWEST IOWA BY
ABOUT 18Z TODAY. INSTABILITY FROM ABOUT 850MB TO 700MB OVER
SOUTHEAST NEBRASKA INTO WESTERN IOWA ALLOWING CONVECTIVE ELEMENTS TO
DEVELOP IN THOSE AREAS BUT THE INSTABILITY NOT REAL IMPRESSIVE SO
NOT THINKING THAT IT WILL PLAY A HUGE ROLE IN THE WEATHER OVER THE
NEXT 24 HOURS. DO EXPECT SOME INCREASED RAINFALL RATES IN NORTHWEST
IOWA HOWEVER AND THE MAIN CONCERN WILL BE A RIBBON OF FREEZING
PRECIPITATION AND SLEET FROM SIOUX CITY TOWARDS SHELDON INTO PARTS
OF SOUTHWEST MINNESOTA THROUGH ABOUT LATE MORNING. FARTHER WEST IT
SHOULD BE MAINLY SNOW AND A BAND OF HEAVY SNOWFALL STILL LOOKS GOOD
FROM YANKTON TO SIOUX FALLS INTO SOUTHWEST MINNESOTA. UPPER LEVEL PV
ADVECTION MAXIMIZES THIS MORNING AND THE 750MB TO 650MB FRONT IS
PLANTED RIGHT OVER SOUTHEAST SOUTH DAKOTA INTO SOUTHWEST MINNESOTA.
WHILE THERE IS SOME INSTABILITY ABOVE THE FRONT IT IS NOT NEARLY AS
IMPRESSIVE AS LAST WEEKS SYSTEM. SO AT THIS TIME NOT PLANNING ON ANY
THUNDER SNOW BUT SNOWFALL RATES OF AN INCH AN HOUR AT TIMES STILL
LIKELY. THE BEST CHANCE FOR THE HEAVIEST SNOWFALL RATES WILL BE FROM
ABOUT 12Z THROUGH 19Z SHIFTING FROM FROM SOUTH TO NORTH. STILL
EXPECT SNOW TO CONTINUE THROUGH THE REMAINDER OF THE AFTERNOON AND
EVENING...DECREASING PRETTY QUICKLY FOR THE WEST TONIGHT.
THE 21Z SREF HAS PRETTY GOOD CLUSTERING AROUND 8 TENTHS OF AN INCH
OF LIQUID AROUND SIOUX FALLS WHILE THE LATEST GEM/ECMWF/NAM ARE
CLOSER TO 6 TO 7 TENTHS OF LIQUID. THE 3Z SREF HAS DROPPED OFF QUITE
A BIT WITH STORM TOTAL LIQUID AFTER 12Z THIS MORNING ABOUT
0.45...THIS TAKING AWAY THE 0.13 IT HAD IN BEFORE 12Z WHICH DOES NOT
LOOK LIKE IT WILL OCCUR. IN FACT MOST AREAS WEST OF A YANKTON TO
SLAYTON LINE LIKELY WILL GET ONLY A COUPLE OF TENTHS OR LESS
THROUGH 12Z THIS MORNING WITH MAYBE AN INCH OR SO FROM THE JAMES
VALLEY WEST. TAKING THIS INTO ACCOUNT WITH ALL OF THE MODELS LOOKS
LIKE WE WILL SETTLE IN TO MORE OF A 4 TO 6 TENTHS LIQUID
POTENTIAL. GIVEN SOME COMPACTION AND MELTING AS IT FALLS 4 TO 6
INCHES SEEMS ABOUT RIGHT FOR THE SIOUX FALLS AREA WITH AN INCH OR
TWO MORE IN SOUTHWEST MINNESOTA. A LITTLE WORRIED THAT THE
SNOWFALL FALLING DURING THE DAY VERSUS AT NIGHT LIKE LAST WEEK AND
LESS INSTABILITY THAN THAT SYSTEM AS WELL AS SURFACE TEMPERATURES
ABOUT 2-3 DEGREES WARMER WILL KEEP AMOUNTS ABOUT 4-5 INCHES.
LATEST RUNS OF THE HRRR AS WELL AS THE RAP KEEP THE BETTER AMOUNTS
JUST EAST AND NORTH OF THE INTERSTATE 29 CORRIDOR WHICH MATCHES
FAIRLY WELL WITH THE MID LEVEL BOUNDARY...AROUND 700MB AND THE
EDGE OF THE DRY SLOT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 420 AM CDT THU APR 18 2013
FRIDAY AND SATURDAY WILL CONTINUE TO SEE BELOW NORMAL TEMPERATURES
ESPECIALLY WITH THE SNOW COVER. ANOTHER SYSTEM WILL BRING THE
CHANCE FOR RAIN OR SNOW TO THE AREA SATURDAY AND SATURDAY NIGHT
BUT IS NOT EXPECTED TO BE A MAJOR IMPACT.
THE SUNDAY INTO MIDDLE OF NEXT WEEK PERIOD IS CHARACTERIZED BY
CONTINUED BELOW NORMAL TEMPERATURES WITH TROUGHING OVER THE CENTRAL
US. SUNDAY COULD ACTUALLY BE ONE OF THE WARMER DAYS WITH HIGHS
GETTING INTO THE 50S OVER PORTIONS OF THE AREA. STAYED ON THE COOLER
SIDE OF GUIDANCE FOR NOW...WITH THE THOUGHT THAT AT LEAST SOME SNOW
COVER REMAINS OVER A GOOD PORTION OF THE CWA. BUT IF SNOW IS MAINLY
GONE...SUNDAY COULD BE SEVERAL DEGREES WARMER THAN CURRENTLY
FORECAST. AS THE THE LONGWAVE TROUGH BUILDS IN...OUR AREA WILL SEE
MULTIPLE SHORTWAVES TRAVERSE THE AREA. THUS THE THE THREAT OF RAIN
SHOWERS CONTINUE SUNDAY INTO SUNDAY NIGHT. NOT LOOKING AT A LOT OF
QPF...BUT MOST PLACES SHOULD GET SOMETHING. COLD FRONT MOVES THROUGH
MONDAY INTO MONDAY NIGHT. WITH THE MID LEVEL FRONT THE THREAT OF
RAIN SHOWERS WILL CONTINUE. THERMAL PROFILES GET COLD ENOUGH THAT WE
COULD SEE SOME SNOW MIX IN LATER MONDAY INTO MONDAY NIGHT...BUT AT
THIS TIME WITH THE WAVE MORE PROGRESSIVE...DOES NOT LOOK LIKE WE SEE
MUCH IN THE WAY OF ANY ACCUMULATING SNOW...BUT WILL HAVE TO MONITOR
MODEL TRENDS. THE SYSTEM MOVES EAST ON TUESDAY...WHICH SHOULD LEAD
TO A MAINLY DRY COUPLE DAYS...ALTHOUGH HIGHS WILL BE STUCK IN THE
40S ON TUESDAY WITH THE TROUGH OVERHEAD. A SLOW WARMING TREND SHOULD
BEGIN BY WEDNESDAY...WITH HIGHS GETTING INTO THE UPPER 40S TO MID
50S. LONGER RANGE GUIDANCE CONTINUES TO SUGGEST A WARMING TREND
LATER NEXT WEEK INTO THE WEEKEND...WITH ACTUAL SPRING LIKE WEATHER
POSSIBLY FINALLY ARRIVING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 643 AM CDT THU APR 18 2013
SNOW WILL CONTINUE TO INCREASE IN INTENSITY THIS MORNING...WITH CIGS
AND VISIBILITIES DROPPING INTO THE IFR CATEGORY. A PERIOD OF HEAVIER
SNOW MAY DROP VIS DOWN BELOW A MILE AT TIMES MID MORNING INTO EARLY
THIS AFTERNOON...MAINLY ALONG AND EAST OF INTERSTATE 29. THE SNOW
WILL TAPER OFF FROM WEST TO EAST THIS EVENING WITH IMPROVING
VISIBILITIES. GUSTY NORTHWEST WINDS ARE ALSO EXPECTED TODAY...WITH
GUSTS UP TO 40 MPH. SKIES WILL SLOWLY CLEAR FROM WEST TO EAST TONIGHT
AS WELL. KEPT MVFR CIGS AT KFSD AND KSUX AS THINK LOW STRATUS WILL
STICK AROUND...BUT WILL HAVE TO MONITOR CLEARING TRENDS AS IT MAY
CLEAR OUT EARLIER IF ENOUGH LOW LEVEL DRY AIR CAN ADVECT IN.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR SDZ038-039-050-
052>055-057>061-063>066-068>071.
WINTER STORM WARNING UNTIL 1 AM CDT FRIDAY FOR SDZ040-056-062-
067.
MN...WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR MNZ090.
WINTER STORM WARNING UNTIL 1 AM CDT FRIDAY FOR MNZ071-072-080-
081-089-097-098.
IA...WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR IAZ002-003-
012>014-020-021-031.
WINTER STORM WARNING UNTIL 1 AM CDT FRIDAY FOR IAZ001.
NE...WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR NEZ013-014.
&&
$$
UPDATE...MJF
SHORT TERM...08
LONG TERM...CHENARD
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
649 AM CDT THU APR 18 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 420 AM CDT THU APR 18 2013
UPPER LEVEL SUPPORT RAPIDLY EXPANDING NORTHWARD THIS MORNING AND
WILL MAXIMIZE OVER SOUTHEAST SOUTH DAKOTA INTO NORTHWEST IOWA BY
ABOUT 18Z TODAY. INSTABILITY FROM ABOUT 850MB TO 700MB OVER
SOUTHEAST NEBRASKA INTO WESTERN IOWA ALLOWING CONVECTIVE ELEMENTS TO
DEVELOP IN THOSE AREAS BUT THE INSTABILITY NOT REAL IMPRESSIVE SO
NOT THINKING THAT IT WILL PLAY A HUGE ROLE IN THE WEATHER OVER THE
NEXT 24 HOURS. DO EXPECT SOME INCREASED RAINFALL RATES IN NORTHWEST
IOWA HOWEVER AND THE MAIN CONCERN WILL BE A RIBBON OF FREEZING
PRECIPITATION AND SLEET FROM SIOUX CITY TOWARDS SHELDON INTO PARTS
OF SOUTHWEST MINNESOTA THROUGH ABOUT LATE MORNING. FARTHER WEST IT
SHOULD BE MAINLY SNOW AND A BAND OF HEAVY SNOWFALL STILL LOOKS GOOD
FROM YANKTON TO SIOUX FALLS INTO SOUTHWEST MINNESOTA. UPPER LEVEL PV
ADVECTION MAXIMIZES THIS MORNING AND THE 750MB TO 650MB FRONT IS
PLANTED RIGHT OVER SOUTHEAST SOUTH DAKOTA INTO SOUTHWEST MINNESOTA.
WHILE THERE IS SOME INSTABILITY ABOVE THE FRONT IT IS NOT NEARLY AS
IMPRESSIVE AS LAST WEEKS SYSTEM. SO AT THIS TIME NOT PLANNING ON ANY
THUNDER SNOW BUT SNOWFALL RATES OF AN INCH AN HOUR AT TIMES STILL
LIKELY. THE BEST CHANCE FOR THE HEAVIEST SNOWFALL RATES WILL BE FROM
ABOUT 12Z THROUGH 19Z SHIFTING FROM FROM SOUTH TO NORTH. STILL
EXPECT SNOW TO CONTINUE THROUGH THE REMAINDER OF THE AFTERNOON AND
EVENING...DECREASING PRETTY QUICKLY FOR THE WEST TONIGHT.
THE 21Z SREF HAS PRETTY GOOD CLUSTERING AROUND 8 TENTHS OF AN INCH
OF LIQUID AROUND SIOUX FALLS WHILE THE LATEST GEM/ECMWF/NAM ARE
CLOSER TO 6 TO 7 TENTHS OF LIQUID. THE 3Z SREF HAS DROPPED OFF QUITE
A BIT WITH STORM TOTAL LIQUID AFTER 12Z THIS MORNING ABOUT
0.45...THIS TAKING AWAY THE 0.13 IT HAD IN BEFORE 12Z WHICH DOES NOT
LOOK LIKE IT WILL OCCUR. IN FACT MOST AREAS WEST OF A YANKTON TO
SLAYTON LINE LIKELY WILL GET ONLY A COUPLE OF TENTHS OR LESS
THROUGH 12Z THIS MORNING WITH MAYBE AN INCH OR SO FROM THE JAMES
VALLEY WEST. TAKING THIS INTO ACCOUNT WITH ALL OF THE MODELS LOOKS
LIKE WE WILL SETTLE IN TO MORE OF A 4 TO 6 TENTHS LIQUID
POTENTIAL. GIVEN SOME COMPACTION AND MELTING AS IT FALLS 4 TO 6
INCHES SEEMS ABOUT RIGHT FOR THE SIOUX FALLS AREA WITH AN INCH OR
TWO MORE IN SOUTHWEST MINNESOTA. A LITTLE WORRIED THAT THE
SNOWFALL FALLING DURING THE DAY VERSUS AT NIGHT LIKE LAST WEEK AND
LESS INSTABILITY THAN THAT SYSTEM AS WELL AS SURFACE TEMPERATURES
ABOUT 2-3 DEGREES WARMER WILL KEEP AMOUNTS ABOUT 4-5 INCHES.
LATEST RUNS OF THE HRRR AS WELL AS THE RAP KEEP THE BETTER AMOUNTS
JUST EAST AND NORTH OF THE INTERSTATE 29 CORRIDOR WHICH MATCHES
FAIRLY WELL WITH THE MID LEVEL BOUNDARY...AROUND 700MB AND THE
EDGE OF THE DRY SLOT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 420 AM CDT THU APR 18 2013
FRIDAY AND SATURDAY WILL CONTINUE TO SEE BELOW NORMAL TEMPERATURES
ESPECIALLY WITH THE SNOW COVER. ANOTHER SYSTEM WILL BRING THE
CHANCE FOR RAIN OR SNOW TO THE AREA SATURDAY AND SATURDAY NIGHT
BUT IS NOT EXPECTED TO BE A MAJOR IMPACT.
THE SUNDAY INTO MIDDLE OF NEXT WEEK PERIOD IS CHARACTERIZED BY
CONTINUED BELOW NORMAL TEMPERATURES WITH TROUGHING OVER THE CENTRAL
US. SUNDAY COULD ACTUALLY BE ONE OF THE WARMER DAYS WITH HIGHS
GETTING INTO THE 50S OVER PORTIONS OF THE AREA. STAYED ON THE COOLER
SIDE OF GUIDANCE FOR NOW...WITH THE THOUGHT THAT AT LEAST SOME SNOW
COVER REMAINS OVER A GOOD PORTION OF THE CWA. BUT IF SNOW IS MAINLY
GONE...SUNDAY COULD BE SEVERAL DEGREES WARMER THAN CURRENTLY
FORECAST. AS THE THE LONGWAVE TROUGH BUILDS IN...OUR AREA WILL SEE
MULTIPLE SHORTWAVES TRAVERSE THE AREA. THUS THE THE THREAT OF RAIN
SHOWERS CONTINUE SUNDAY INTO SUNDAY NIGHT. NOT LOOKING AT A LOT OF
QPF...BUT MOST PLACES SHOULD GET SOMETHING. COLD FRONT MOVES THROUGH
MONDAY INTO MONDAY NIGHT. WITH THE MID LEVEL FRONT THE THREAT OF
RAIN SHOWERS WILL CONTINUE. THERMAL PROFILES GET COLD ENOUGH THAT WE
COULD SEE SOME SNOW MIX IN LATER MONDAY INTO MONDAY NIGHT...BUT AT
THIS TIME WITH THE WAVE MORE PROGRESSIVE...DOES NOT LOOK LIKE WE SEE
MUCH IN THE WAY OF ANY ACCUMULATING SNOW...BUT WILL HAVE TO MONITOR
MODEL TRENDS. THE SYSTEM MOVES EAST ON TUESDAY...WHICH SHOULD LEAD
TO A MAINLY DRY COUPLE DAYS...ALTHOUGH HIGHS WILL BE STUCK IN THE
40S ON TUESDAY WITH THE TROUGH OVERHEAD. A SLOW WARMING TREND SHOULD
BEGIN BY WEDNESDAY...WITH HIGHS GETTING INTO THE UPPER 40S TO MID
50S. LONGER RANGE GUIDANCE CONTINUES TO SUGGEST A WARMING TREND
LATER NEXT WEEK INTO THE WEEKEND...WITH ACTUAL SPRING LIKE WEATHER
POSSIBLY FINALLY ARRIVING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 643 AM CDT THU APR 18 2013
SNOW WILL CONTINUE TO INCREASE IN INTENSITY THIS MORNING...WITH CIGS
AND VISIBILITIES DROPPING INTO THE IFR CATEGORY. A PERIOD OF HEAVIER
SNOW MAY DROP VIS DOWN BELOW A MILE AT TIMES MID MORNING INTO EARLY
THIS AFTERNOON...MAINLY ALONG AND EAST OF INTERSTATE 29. THE SNOW
WILL TAPER OFF FROM WEST TO EAST THIS EVENING WITH IMPROVING
VISIBILITIES. GUSTY NORTHWEST WINDS ARE ALSO EXPECTED TODAY...WITH
GUSTS UP TO 40 MPH. SKIES WILL SLOWLY CLEAR FROM WEST TO EAST TONIGHT
AS WELL. KEPT MVFR CIGS AT KFSD AND KSUX AS THINK LOW STRATUS WILL
STICK AROUND...BUT WILL HAVE TO MONITOR CLEARING TRENDS AS IT MAY
CLEAR OUT EARLIER IF ENOUGH LOW LEVEL DRY AIR CAN ADVECT IN.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR SDZ038-039-050-
052>055-057>061-063>066-068>071.
WINTER STORM WARNING UNTIL 1 AM CDT FRIDAY FOR SDZ040-056-062-
067.
MN...WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR MNZ090.
WINTER STORM WARNING UNTIL 1 AM CDT FRIDAY FOR MNZ071-072-080-
081-089-097-098.
IA...WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR IAZ002-003-
012>014-020-021-031.
WINTER STORM WARNING UNTIL 1 AM CDT FRIDAY FOR IAZ001.
NE...WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR NEZ013-014.
&&
$$
SHORT TERM...08
LONG TERM...CHENARD
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1227 PM CDT THU APR 18 2013
.AVIATION 18Z DISCUSSION...
OTHER THAN BREEZY CONDITIONS THIS AFTERNOON...ALL EYES ARE ON THE
APPROACHING WEATHER SYSTEM TO OUR WEST. A LINE OF SHOWERS AND
POTENTIALLY SEVERE THUNDERSTORMS ARE EXPECTED TO ROAR THROUGH THE
MID STATE OVERNIGHT. WINDS OFF THE SFC ARE STRONG ENOUGH TO
WARRANT LLWS VALUES OF 45-55KTS BETWEEN 22Z AND 09Z. SFC WINDS
WILL FOR THE MOST PART GUST UP TO 40-45 KTS WITH THE LINE(S) OF
STORMS THAT MOVES THROUGH. SOME PRE FRONTAL ACTIVITY IS ALSO
POSSIBLE AND DUAL LINES COULD FORM. A BRIEF WINDOW OF LIGHT SHOWER
ACTIVITY WILL FOLLOW THE STORMS. PRECIP FREE CONDITIONS FOR CKV
AND BNA ONLY...AFT 14Z....BUT BKN CIG OF 3-5 KFT TO REMAIN.
&&
.PREV DISCUSSION... /ISSUED 617 AM CDT THU APR 18 2013/
UPDATE...FOR 12Z AVIATION FORECAST
AVIATION...
STRONG LINE OF CONVECTION FROM CHICAGO DOWN THROUGH SAINT LOUIS
INTO FAR EASTERN OKLAHOMA AND EASTERN TEXAS WILL MOVE EAST TODAY
AND BE ALONG THE MISSISSIPPII RIVER BY 23Z AND ALONG THE TENNESSEE
RIVER BY 02Z AND INTERSTATE 65 AT 05Z AND ON THE PLATEAU BY 11Z.
LOW LEVEL JET OUT AHEAD OF THE LINE ON THE ORDER OF 65 TO 70 KNOTS
WILL PULL EAST WITH THE LINE TODAY AND TONIGHT. BOUNDARY LAYER
WINDS ALREADY 45 KNOTS AT BNA THIS MORNING WILL LIKELY SUSTAIN
THIS SPEED DURING THE DAY AND EVENING WITH SURFACE WINDS GUSTS TO
30 KNOTS DURING THE DAY AND INTO THE EVENING ACROSS THE MID STATE.
WILL INCLUDE LOW LEVEL WIND SHEAR FOR THIS MORNING AT ALL
TERMINALS. STRONG CAPPING INVERSION BASED AROUND 825 MBARS WILL
PRECLUDE ANY THUNDERSTORM DEVELOPMENT UNTIL TONIGHT. ONCE SQUALL
LINE PASSES TONIGHT LOOK FOR GUSTY WEST WINDS TO FOLLOW.
BOYD
PREV DISCUSSION... /ISSUED 400 AM CDT THU APR 18 2013/
.MODERATE RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO
TONIGHT...
DISCUSSION...
FEW OVERALL CHANGES TO THE FORECAST OVER THE NEXT WEEK...WITH
MAINLY SLIGHT ADJUSTMENTS TO TEMPS AND TIMING OF PRECIP. A LARGE
H5 TROUGH OVER THE PLAINS STATES WILL SHIFT INTO THE MISSISSIPPI
VALLEY TODAY THEN ACROSS THE TENNESSEE VALLEY TONIGHT...WITH AN
ASSOCIATED STRONG COLD FRONT SWEEPING THROUGH THE MID STATE
TONIGHT. BEFORE THE FRONT ARRIVES...ANOTHER SUMMER-LIKE DAY IS ON
TAP WITH TEMPERATURES STARTING OUT IN THE 60S TO AROUND 70 THIS
MORNING THEN WARMING UP INTO THE LOW TO MID 80S AREAWIDE THIS
AFTERNOON. AS A SUB-1000MB SURFACE LOW TAKES SHAPE ACROSS THE
MIDWEST...925MB WINDS WILL INCREASE ACROSS OUR REGION INTO THE
40-50KT RANGE TODAY LEADING TO GUSTY SOUTH WINDS AT THE SURFACE.
ANTICIPATING SOUTH WINDS IN THE 15 TO 30 MPH RANGE DEVELOPING LATER
THIS MORNING...THEN CONTINUING INTO THE AFTERNOON HOURS BEFORE
SUBSIDING SOMEWHAT EARLY IN THE EVENING. OCCASIONAL GUSTS TO NEAR
40 MPH APPEAR LIKELY AS WELL BASED ON BUFKIT SOUNDINGS. SOUTH
WINDS WILL INCREASE AGAIN LATER IN THE EVENING AS A SHARP PRESSURE
GRADIENT MOVES ACROSS THE MID STATE AHEAD OF THE COLD FRONT. TO
SIMPLIFY MATTERS...HAVE ISSUED A WIND ADVISORY FOR ALL ZONES
BEGINNING LATER THIS MORNING AND CONTINUING THROUGH THE EARLY
MORNING HOURS ON FRIDAY.
SPC HAS PLACED AREAS ALONG AND WEST OF THE I-65 CORRIDOR IN A
MODERATE RISK FOR SEVERE STORMS THURSDAY EVENING WITH A SLIGHT
RISK TO THE EAST THURSDAY NIGHT. 00Z GFS/NAM/ECMWF AND LATEST
HIGH RESOLUTION 4.0 KM WRF...NSSL WRF...AND HRRR ALL INDICATE A
STRONG TO SEVERE QLCS WILL FORM LATER TODAY ALONG THE
FRONT...REACHING THE TENNESSEE RIVER BY MID EVENING...I-65
CORRIDOR AROUND MIDNIGHT...AND EXIT EAST OF THE CWA NEAR/AFTER
SUNRISE FRIDAY MORNING. MODELS CONTINUE TO DEPICT GENERALLY WEAK
INSTABILITY AROUND 500 J/KG AHEAD OF THE LINE...BUT SOME GUIDANCE
INDICATES A SURGE OF MID/UPPER 60S DEWPOINTS COMING NORTHWARD
AHEAD OF THE QLCS WHICH COULD BUMP UP CAPE VALUES TO NEAR/OVER
1000 J/KG ACROSS WESTERN ZONES. REGARDLESS...IMPRESSIVE 0-3KM SRH
STRENGTHENING INTO THE 500-800 M2/S2 RANGE AND VERY LONG CURVED
HODOGRAPHS SUGGESTS A SIGNIFICANT DAMAGING WIND THREAT WITH THE
LINE OF STORMS ALONG WITH SOME QLCS TORNADOES. HIGHEST RISK OF
DAMAGING WINDS/TORNADOES IS EXPECTED TO BE ALONG/WEST OF I-65 IN
THE 02-06Z TIMEFRAME ACROSS THE MODERATE RISK AREA...AS STORMS
WILL ENCOUNTER INCREASINGLY LESS INSTABILITY AND WEAKENING SHEAR
OFF TO THE EAST.
STRATIFORM RAIN AND A FEW THUNDERSTORMS WILL CONTINUE MUCH OF THE
NIGHT BEHIND THE QLCS WITH RAINFALL COMING TO AN END FROM WEST TO
EAST FRIDAY MORNING. MUCH COOLER TEMPERATURES ARE ANTICIPATED
FRIDAY AND SATURDAY WITH LOWS FALLING INTO THE MID TO UPPER 30S
SATURDAY MORNING. WITH SURFACE RIDGE SETTLING OVER THE MID
STATE...LIGHT TO CALM WINDS...AND DEWPOINTS FALLING INTO THE 20S
AND 30S...PATCHY FROST APPEARS POSSIBLE FOR MUCH OF THE FORECAST
AREA AND HAVE ADDED MENTION TO ZONES. AREA WILL BEGIN TO WARMUP
FROM SUNDAY INTO EARLY NEXT WEEK AS SOUTHERLY FLOW BEGINS ANEW.
FEW CHANGES WERE MADE IN THE EXTENDED FORECAST WITH NEXT CHANCE
FOR RAIN AROUND TUESDAY/WEDNESDAY OF NEXT WEEK.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 1 AM CDT FRIDAY FOR TNZ005>011-022>034-
056>066-075-077>080-093>095.
&&
$$
21
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1230 PM CDT THU APR 18 2013
.UPDATE...AREA OF RAIN HAS PUSHED OUT OF THE AREA...AS LOW LEVEL
JET FORCING HAS SHIFTED TO THE EAST. HRRR AND 4KM WRF/NMM HAVE
HANDLED THIS WELL...AND SHOW A LINE OF SHOWERS AND A FEW
THUNDERSTORMS SHIFTING NORTHEAST THROUGH THE AREA FROM MID TO LATE
AFTERNOON/EARLY EVENING. THIS IS IN RESPONSE TO SURFACE LOW AND
COLD FRONT MOVING NORTHEAST THROUGH THE AREA.
THUS...ADJUSTED FORECAST FOR DRIZZLE UNTIL THESE SHOWERS AND
ISOLATED STORMS PUSH THROUGH. THIS WILL BE THE LAST ROUND OF
RAINFALL ACROSS THE AREA...SO HAVE PUSHED UP THE ENDING TIME OF
THE AREAL FLOOD WATCH TO 9 PM THIS EVENING. THERE WILL OBVIOUSLY
STILL BE FLOODING PROBLEMS NEAR AREA RIVERS FOR AWHILE...AND SOME
FLOODING IN LOW LYING AREAS. HOWEVER...THE RISK FOR MORE AREAL
FLOODING SHOULD SUBSIDE AFTER THIS LAST ROUND OF PRECIPITATION
EXITS THE AREA EARLY THIS EVENING.
ADJUSTED HIGHS DOWN A BIT...AS LOW PUSHING WARMER AIR NORTHWARD
TOWARD THE FAR SOUTHERN PORTIONS OF THE AREA WILL BATTLE COOLER
AIR WITH CLOUDS AND ANY PRECIPITATION AREAS.
&&
.AVIATION/18Z TAFS/...CEILINGS BETWEEN ALTERNATE MINIMUMS AND
AIRPORT MINIMUMS WILL PERSIST ACROSS TAF SITES THIS AFTERNOON AND
INTO TONIGHT. VISIBILITIES SHOULD REMAIN MAINLY VFR THIS AFTERNOON
AND TONIGHT. LINE OF SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO MOVE NORTHEAST THROUGH TAF SITES BETWEEN 21Z THURSDAY
AND 01Z FRIDAY. MAY SEE VISIBILITIES DOWN TO NEAR ALTERNATE
MINIMUMS WITH THE PRECIPITATION.
LIGHT WINDS THIS AFTERNOON WILL SHIFT SOUTHWEST AFTER THE LOW
PRESSURE SYSTEM PASSES NORTHEAST THROUGH THE AREA EARLY THIS
EVENING. THESE WINDS WILL QUICKLY BECOME GUSTY BY LATE EVENING AND
LINGER OVERNIGHT. THEY WILL VEER WEST ON FRIDAY AND REMAIN GUSTY.
SUSTAINED WINDS TO 23 KNOTS...AND GUSTS TO 35 KNOTS...ARE
POSSIBLE AT TIMES LATE TONIGHT AND FRIDAY.
SHOULD SEE SCATTERED LIGHT SNOW SHOWERS BETWEEN 10Z AND 14Z
FRIDAY AT MADISON. ANY ACCUMULATIONS WILL BE LIMITED TO A DUSTING
AT WORST ON GRASSY AREAS...WITH THE RUNWAYS JUST REMAINING WET.
THIS SHOULD CHANGE TO SCATTERED RAIN SHOWERS BY MID MORNING AND
LINGER THROUGH THE REST OF THE DAY. THE EASTERN SITES SHOULD SEE
SCATTERED RAIN SHOWERS THROUGH THE DAY.
&&
.MARINE...ISSUED A SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING
UNTIL 2 AM FRIDAY MORNING...AND A GALE WARNING FROM 2 AM FRIDAY
MORNING UNTIL 7 PM FRIDAY EVENING. LOW PRESSURE WILL STRENGTHEN AS
IT SHIFTS NORTHEASTWARD THROUGH THE REGION TONIGHT AND FRIDAY.
THIS WILL ALLOW FOR GUSTY SOUTHWEST WINDS TO DEVELOP OVER THE
NEARSHORE WATERS THIS EVENING. THESE WINDS WILL INCREASE IN
MAGNITUDE LATER TONIGHT INTO FRIDAY...VEERING TO THE WEST.
FREQUENT GUSTS TO 35 KNOTS ARE EXPECTED DURING THIS TIME. HIGH
WAVES WILL OCCUR TOWARD THE OPEN WATERS...WITH THE OFFSHORE FLOW.
&&
.PREV DISCUSSION... /ISSUED 500 AM CDT THU APR 18 2013/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM
BEST ELEVATED INSTABILITY AND HEAVIEST RAINFALL HAS STAYED OVER IL
DURING THE OVERNIGHT AND EXPECT THIS SCENARIO TO CONTINUE AS THE
50-60 KT LLJ LIFTS NEWD FROM IL INTO MI. THE INVERTED TROUGH OVER
ERN IA AND WRN WI WILL SHIFT EAST ACROSS SRN WI THIS AM AND THEN
ANOTHER ROUND OF CYCLOGENESIS OVER NRN IL OR SRN WI AS THE UPPER
TROUGH APPROACHES FROM THE PLAINS. THE LOW WILL DEEPEN THE MOST
AFTER IT LIFTS TO THE NE TOWARD THE NRN GREAT LAKES. A LARGE DRY
SLOT WILL THEN FOLLOW FOR TNT WITH LITTLE ADDITIONAL PCPN. THE UPPER
TROUGH AXIS WILL THEN APPROACH THE WRN CWA BY FRI AM WITH INCREASED
SATURATION AND BETTER CHANCES OF LIGHT SNOW.
ADDITIONAL RAINFALL AMOUNTS FOR TODAY WILL RANGE FROM 0.40 INCHES IN
THE FAR NW CWA TO JUST UNDER AN INCH IN SE WI. OVERALL THE NRN CWA
HAS ESCAPED THE HEAVY RAINS...SO ANY RIVERS THAT HAVE THEIR
HEADWATERS IN THIS AREA WILL NOT FLOOD AS BADLY AS FIRST THOUGHT.
NEW RIVER FORECASTS THAT INCLUDE THE LESSER RAIN TOTALS WILL BE
ISSUED LATER THIS MORNING.
FRIDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
SURFACE LOW PRESSURE CENTERED OVER CENTRAL UPPER MICHIGAN WILL
GRADUALLY SHIFT INTO EASTERN ONTARIO LATE IN THE DAY. THE SLOW
MOVEMENT IS IN RESPONSE TO THE UPPER LOW CLOSING OFF AND BECOMING
NEGATIVELY TILTED OVER LAKE SUPERIOR...AND THE SURFACE LOW
OCCLUDING. COLD AIR WILL SLOWLY MOVE INTO SOUTHERN WI ON THE BACK
SIDE OF THIS SYSTEM.
THE PRECIP SHIELD WITHIN THE DEFORMATION ZONE WILL BE QUITE
EXPANSIVE. MODELS SHOW STRONG 700-300MB Q-VECTOR CONVERGENCE OVER
MUCH OF WI FRIDAY MORNING...ALONG WITH STEEP LOW LEVEL LAPSE RATES
AND CYCLONIC FLOW ALOFT. FORECAST TEMPERATURE PROFILES SHOW A
SHALLOW LAYER RIGHT AROUND FREEZING AT THE GROUND...BUT BELOW
FREEZING TEMPS JUST ABOVE ON FRIDAY MORNING. THE NAM IS COLDER THAN
THE GFS AND ECMWF. MOISTURE WILL BE SHALLOW...SO IT IS POSSIBLE THAT
WE SEE DRIZZLE INSTEAD OF RAIN OR SNOW FOR SOME OF THE TIME. ONLY A
LIGHT DUSTING OF SNOW AT BEST FOR THE WEST HALF OF THE FORECAST
AREA.
BY MIDDAY FRIDAY...SURFACE TEMPS WILL BE ABOVE FREEZING...AND ANY
MIXED PRECIP WILL TRANSITION BACK TO RAIN. IT WILL BE A CHILLY DAY
WITH HIGHS ONLY IN THE UPPER 30S AND LOWER 40S.
ANOTHER CONCERN FOR FRIDAY WILL BE THE GUSTY WEST WINDS DUE TO THE
TIGHT PRESSURE GRADIENT OVERHEAD. GUSTS UP TO 35 MPH WILL BE LIKELY
WITH EFFICIENT MIXING OF HIGHER WINDS AT AROUND 5000 FEET DOWN TO
THE SURFACE. SUSTAINED WINDS UP TO 25 MPH WITH GUSTS OVER 35 MPH ARE
LIKELY. EXPECTING WINDS TO REMAIN BELOW WIND ADVISORY CRITERIA...BUT
IT WILL BE CLOSE.
PRECIP CHANCES TAPER OFF SIGNIFICANTLY EARLY FRIDAY EVENING WITH
LOSS OF DAYTIME HEATING/INSTABILITY...AS DRY AIR AND HIGH PRESSURE
MOVE INTO THE REGION.
LONG TERM...
SATURDAY AND SUNDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
SURFACE HIGH PRESSURE AND UPPER LEVEL RIDGING WILL DRIFT OVERHEAD ON
SATURDAY...BRINGING LIGHT WINDS AND SUNSHINE. A LAKE BREEZE IS
EXPECTED BY EARLY SATURDAY AFTERNOON. MAX TEMPS WILL ONLY REACH THE
MID 40S NEAR THE LAKE...BUT UPPER 40S WELL INLAND.
CLOUDS WILL BEGIN TO MOVE IN SAT NIGHT AND OVERSPREAD THE AREA ON
SUNDAY AS LOW PRESSURE APPROACHES FROM THE PLAINS. ISENTROPIC LIFT
AND WEAK WARM AIR ADVECTION WILL BRING LIGHT RAIN CHANCES TO SOUTH
CENTRAL WI ON SUNDAY. BEST CHANCE FOR PRECIP WILL BE INLAND FROM THE
LAKE SINCE THERE WILL BE QUITE A BIT OF DRY AIR ON EASTERLY WINDS
EATING AWAY AT IT.
GFS SHOWS PRECIP CHANCES FOR SOUTHERN WI SUN NIGHT/MON MORNING WHILE
THE ECMWF IS DRY.
MONDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE MEDIUM.
AN UPPER TROUGH WILL DEVELOP AND BECOME MORE AMPLIFIED DURING THE
FIRST HALF OF THE WEEK OVER THE CENTRAL US. SEVERAL SHORTWAVES WILL
MOVE THROUGH WI AHEAD OF THIS UPPER TROUGH AND BRING MORE ROUNDS OF
RAIN TO THE REGION. THE BEST CHANCE FOR RAIN LOOKS LIKE MONDAY NIGHT
THROUGH TUESDAY MORNING. RAIN MAY TRANSITION TO SNOW BY TUE NIGHT.
IT ONLY LOOKS LIKE MINOR SNOW AMOUNTS AT THIS TIME.
AVIATION/12Z TAFS/...ROUNDS OF SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE TODAY AS LOW PRESSURE MOVES ACROSS THE REGION. IFR
CIGS OR LESS WILL PREVAIL WITH VSBYS MAINLY RANGING FROM 2-5 MILES.
SWLY WINDS AND A DRY SLOT WILL REDUCE THE CHANCES FOR RAIN AND
IMPROVE THE VSBYS. CIGS WILL SLOWLY RISE TO 1.0-2.0 KFT.
MARINE...A GALE WATCH IS IN EFFECT LATE TONIGHT AND FRIDAY AS
SOUTHWEST TO WEST WINDS INCREASE DUE TO STRONG LOW PRESSURE OVER THE
NORTHERN GREAT LAKES. WEST WINDS UP TO 20 TO 25 KNOTS AND GUSTS TO
35 KNOTS ARE EXPECTED. HIGH WAVES WILL OCCUR TOWARD THE OPEN WATERS
OF LAKE MI.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...FLOOD WATCH UNTIL 9 PM CDT THIS EVENING FOR WIZ046-047-051-052-
056>060-062>072.
LM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 2 AM CDT FRIDAY
FOR LMZ643>646.
GALE WARNING FROM 2 AM TO 7 PM CDT FRIDAY FOR LMZ643>646.
&&
$$
UPDATE...WOOD
TODAY/TONIGHT AND AVIATION/MARINE...GEHRING
FRIDAY THROUGH WEDNESDAY...MRC