Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 06/14/13
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
817 PM CDT THU JUN 13 2013
.UPDATE...
COLD FRONT CONTINUES TO WORK ITS WAY ACROSS THE STATE THIS EVENING
WITH THE BOUNDARY EASY TO SPOT ON WSR-88D IMAGERY. A FEW SHOWERS
HAVE DEVELOPED OVER SOUTHEAST ARKANSAS ALONG THE BOUNDARY BUT WITH
LOSS OF HEATING...NOT EXPECTING THESE TO REMAIN TOGETHER MUCH
LONGER. CURRENT PRECIPITATION GRIDS...AND ALL GRIDS FOR THAT
MATTER...REMAIN IN GOOD SHAPE AND NO CHANGES ARE NEEDED TONIGHT.
TEMPERATURES ACROSS THE BOUNDARY ARE SLIGHTLY COOLER BUT DEW POINT
TEMPERATURES ARE MUCH LOWER. DEW POINT AT THE WFO HAVE DROPPED 8
DEGREES IN THE PAST HOUR AFTER FROPA WITH THE DRIER AIR MOVING
SOUTH BEHIND THE BOUNDARY.
&&
.PREV DISCUSSION... /ISSUED 645 PM CDT THU JUN 13 2013/
AVIATION...
A COLD FRONT IS MOVING THROUGH ARKANSAS AT THIS TIME. A SHOWER
DEVELOPED SOUTH OF CONWAY AND IS MOVING SOUTHEAST ALONG THE
BOUNDARY. EXPECT THIS TO BE A SHORT LIVED SHOWER BUT BROKEN
CUMULUS WILL BE POSSIBLE AT LIT AND PBF FOR THE NEXT COUPLE OF
HOURS. OTHERWISE...CLOUDS WILL DISSIPATE DURING LATE EVENING.
HIGH PRESSURE WILL BUILD INTO THE AREA FRIDAY AND SOME SCATTERED
CUMULUS ARE EXPECTED IN CENTRAL AND SOUTH SECTIONS. VFR CONDITIONS
WILL PREVAIL.
PREV DISCUSSION... /ISSUED 245 PM CDT THU JUN 13 2013/
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
W-E ORIENTED CDFNT WAS SITUATED ACRS CNTRL AR AT MID AFTN. DEWPOINTS
IN THE LOWER AND MID 70S HAVE POOLED IN THE VCNTY OF THE BNDRY...
RESULTING IN HEAT INDICES BETWEEN 100 AND 105 DEGREES. HAVE SEEN A
FEW WEAK RADAR RETURNS OVR ERN AR. THE RUC AND HRRR MODELS CONT TO
INDCD ISOLD SHRA/TSRA DVLPG ALONG THE FNT OVR CNTRL/SERN AR LATE
THIS AFTN/EARLY EVENING. THUS...WL LEAVE SOME SMALL POPS IN PER
GOING FCST.
THE AFOREMENTIONED CDFNT WL EVENTUALLY STALL OUT TO THE SW OF THE
AREA BY FRI AS A WEAK SFC RDG BLDS INTO AR. THE BNDRY WL MEANDER IN
THE VCNTY OF WRN AR HEADING INTO THE WEEKEND. CANNOT RULE OF A STRAY
SHRA/TSRA FRI AND SAT ALONG WITH WRN PERIPHERY OF THE SFC RDG...BUT
WL KEEP A DRY FCST IN PLACE. E/NELY SFC WINDS BEHIND THE FNT WL
BRING DRIER AND SLIGHTLY COOLER AIRMASS TO MUCH OF THE FA.
THE SFC HIGH WL WEAKEN ENOUGH BY SUN/SUN NGT FOR A RETURN OF SLY
WINDS...ALONG WITH INCRSG LOW LVL RH. MEANWHILE...THE UPR LVL FLOW
WL FLATTEN TO ALLOW A NEW CDFNT WL APCH AR FM THE N...ALONG WITH A
BETTER CHC OF SHRA/TSRA. THE UNSETTLED PATTERN WL CONT INTO THE LONG
TERM PD.
LONG TERM...MONDAY THROUGH THURSDAY
UPPER RIDGE WILL BE PUSHED SOUTH OF THE STATE FOR THE BEGINNING OF
NEXT WEEK...AND ALLOW A COLD FRONT TO MOVE INTO THE STATE. MODELS
ARE IN BETTER AGREEMENT OF MOVING THIS FRONT FURTHER INTO THE STATE
THAN PREVIOUS RUNS...AND HAVE INCREASED POPS TO THE CHANCE CATEGORY
FOR MONDAY INTO TUESDAY. UPPER RIDGE WILL BEGIN TO BUILD BACK OVER
THE AREA WEDNESDAY INTO THURSDAY...WITH RAIN CHANCES DWINDLING.
TEMPERATURES WILL CONTINUE TO BE ABOVE NORMAL ACROSS THE SOUTH...
WHILE NORTHERN ARKANSAS WILL HAVE A LITTLE COOLER TEMPERATURES DUE
TO CLOUD COVER AND RAINFALL.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 66 87 64 89 / 0 0 0 10
CAMDEN AR 71 94 65 94 / 20 10 10 10
HARRISON AR 65 87 65 90 / 0 10 10 10
HOT SPRINGS AR 72 91 67 93 / 10 10 10 10
LITTLE ROCK AR 71 90 68 92 / 10 0 0 10
MONTICELLO AR 72 91 66 93 / 20 0 10 10
MOUNT IDA AR 68 92 64 91 / 10 10 10 10
MOUNTAIN HOME AR 65 86 66 90 / 0 0 0 10
NEWPORT AR 67 87 66 90 / 0 0 0 10
PINE BLUFF AR 71 91 66 91 / 20 0 10 10
RUSSELLVILLE AR 70 90 67 92 / 0 10 10 10
SEARCY AR 69 89 64 90 / 10 0 0 10
STUTTGART AR 70 89 67 90 / 10 0 0 10
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
56
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
645 PM CDT THU JUN 13 2013
.AVIATION...
A COLD FRONT IS MOVING THROUGH ARKANSAS AT THIS TIME. A SHOWER
DEVELOPED SOUTH OF CONWAY AND IS MOVING SOUTHEAST ALONG THE
BOUNDARY. EXPECT THIS TO BE A SHORT LIVED SHOWER BUT BROKEN
CUMULUS WILL BE POSSIBLE AT LIT AND PBF FOR THE NEXT COUPLE OF
HOURS. OTHERWISE...CLOUDS WILL DISSIPATE DURING LATE EVENING.
HIGH PRESSURE WILL BUILD INTO THE AREA FRIDAY AND SOME SCATTERED
CUMULUS ARE EXPECTED IN CENTRAL AND SOUTH SECTIONS. VFR CONDITIONS
WILL PREVAIL.
&&
.PREV DISCUSSION... /ISSUED 245 PM CDT THU JUN 13 2013/
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
W-E ORIENTED CDFNT WAS SITUATED ACRS CNTRL AR AT MID AFTN. DEWPOINTS
IN THE LOWER AND MID 70S HAVE POOLED IN THE VCNTY OF THE BNDRY...
RESULTING IN HEAT INDICES BETWEEN 100 AND 105 DEGREES. HAVE SEEN A
FEW WEAK RADAR RETURNS OVR ERN AR. THE RUC AND HRRR MODELS CONT TO
INDCD ISOLD SHRA/TSRA DVLPG ALONG THE FNT OVR CNTRL/SERN AR LATE
THIS AFTN/EARLY EVENING. THUS...WL LEAVE SOME SMALL POPS IN PER
GOING FCST.
THE AFOREMENTIONED CDFNT WL EVENTUALLY STALL OUT TO THE SW OF THE
AREA BY FRI AS A WEAK SFC RDG BLDS INTO AR. THE BNDRY WL MEANDER IN
THE VCNTY OF WRN AR HEADING INTO THE WEEKEND. CANNOT RULE OF A STRAY
SHRA/TSRA FRI AND SAT ALONG WITH WRN PERIPHERY OF THE SFC RDG...BUT
WL KEEP A DRY FCST IN PLACE. E/NELY SFC WINDS BEHIND THE FNT WL
BRING DRIER AND SLIGHTLY COOLER AIRMASS TO MUCH OF THE FA.
THE SFC HIGH WL WEAKEN ENOUGH BY SUN/SUN NGT FOR A RETURN OF SLY
WINDS...ALONG WITH INCRSG LOW LVL RH. MEANWHILE...THE UPR LVL FLOW
WL FLATTEN TO ALLOW A NEW CDFNT WL APCH AR FM THE N...ALONG WITH A
BETTER CHC OF SHRA/TSRA. THE UNSETTLED PATTERN WL CONT INTO THE LONG
TERM PD.
LONG TERM...MONDAY THROUGH THURSDAY
UPPER RIDGE WILL BE PUSHED SOUTH OF THE STATE FOR THE BEGINNING OF
NEXT WEEK...AND ALLOW A COLD FRONT TO MOVE INTO THE STATE. MODELS
ARE IN BETTER AGREEMENT OF MOVING THIS FRONT FURTHER INTO THE STATE
THAN PREVIOUS RUNS...AND HAVE INCREASED POPS TO THE CHANCE CATEGORY
FOR MONDAY INTO TUESDAY. UPPER RIDGE WILL BEGIN TO BUILD BACK OVER
THE AREA WEDNESDAY INTO THURSDAY...WITH RAIN CHANCES DWINDLING.
TEMPERATURES WILL CONTINUE TO BE ABOVE NORMAL ACROSS THE SOUTH...
WHILE NORTHERN ARKANSAS WILL HAVE A LITTLE COOLER TEMPERATURES DUE
TO CLOUD COVER AND RAINFALL.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 66 87 64 89 / 0 0 0 10
CAMDEN AR 71 94 65 94 / 20 10 10 10
HARRISON AR 65 87 65 90 / 0 10 10 10
HOT SPRINGS AR 72 91 67 93 / 10 10 10 10
LITTLE ROCK AR 71 90 68 92 / 10 0 0 10
MONTICELLO AR 72 91 66 93 / 20 0 10 10
MOUNT IDA AR 68 92 64 91 / 10 10 10 10
MOUNTAIN HOME AR 65 86 66 90 / 0 0 0 10
NEWPORT AR 67 87 66 90 / 0 0 0 10
PINE BLUFF AR 71 91 66 91 / 20 0 10 10
RUSSELLVILLE AR 70 90 67 92 / 0 10 10 10
SEARCY AR 69 89 64 90 / 10 0 0 10
STUTTGART AR 70 89 67 90 / 10 0 0 10
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...51
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
339 PM EDT Wed Jun 12 2013
.NEAR TERM [Through Tonight]...
Isolated to scattered thunderstorms will develop this afternoon,
mainly between I-10 and the coast. This is where the low level
convergence and MLCAPE will be greatest as the slow-moving sea
breeze fronts interact with orthogonal horizontal convective rolls.
Most of the cumulus clouds will be unable to grow substantially
because of the very dry air above 700 mb, but in a few spots (where
mesoscale forcing is strongest and CAPE/boundary layer moisture is
maximized) there could be a strong enough updraft to support a pulse
strong/severe storm. Isolated storms may develop in south GA this
evening (as indicated by some of the Convection Allowing Models like
the HRRR and our local WRF), as the FL sea breeze fronts
accelerate inland.
Temperatures were already in the 90s early this afternoon, and
will top out in the mid to upper 90s. Heat index values may reach
105 deg at a few inland locations. Lows tonight will be in the lower
to mid 70s, with plenty of humidity.
&&
.SHORT TERM [Thursday Through Friday Night]...
Despite the upper level ridging over the U.S. which has been keeping
the weather hot and dry (with the exception of afternoon sea-breeze
showers and thunderstorms near the coast), the pattern gets a little
more interesting as a short wave trof digs down the east side of the
ridge. The shortwave trof will enhance surface pressure drops and
upper level winds (and thus shear). A line of showers and
thunderstorms along a weak frontal boundary from the surface low is
expected to dip into our area Thursday night. There is some model
disagreement as to whether or not these storms will dip as far south
as our forecast area, but if they do the model MLCAPE values of
around 3000 J/kg and 0-6 km bulk shear of around 30 kts suggest that
they will be strong to severe storms. SPC has our AL and GA
counties in a slight risk for severe thunderstorms in the day 2
outlook. The bulk shear is a little low for supercell development,
but stronger individual cells may form along the line, especially
with such a high amount of instability. Looking at the Fri 00Z
model soundings, there are conditionally unstable lapse rates
through most of the profile and drier air has made its way in the
mid levels thanks to the high pressure we`ve been under. CAPE
contribution in the -10 to -30 C range is around 1000 J/kg and
DCAPE is 1500-2000 J/kg. These parameters suggest that there is a
threat for both severe winds (58+ MPH) and 1" hail. Lower level
vorticity and wind shear is higher to the north of our area, but a
tornado from a stronger cell can`t be ruled out either.
Highs tomorrow will be in the upper 90s, similar to today, but may
be a little lower Thursday depending on the cloudiness ahead of the
line of storms and the timing of the storms themselves. Lows
Thursday night will be in the low-mid 70s, a little warmer due to
higher cloud cover and rain chances, but return to the lower 70s
Friday night.
&&
.LONG TERM [Saturday through Tuesday]...
After the potential system passes Thursday night, high pressure
aloft and at the surface will build eastward and be the main
synoptic scale influence on the forecast area`s weather through
Tuesday. On Tuesday, another shortwave will propagate through the
upper level ridge and set up a pattern similar to Thursday night
(see short term). Highest PoPs in the forecast period are Tuesday
and Wednesday. Expecting highs in the 90s and lows in the low 70s
through the long term period.
&&
.AVIATION [Through 18Z Thursday]...
Widely scattered TSRA will develop this afternoon from I-10 to the
coast, so there could be a brief period of TSRA at KTLH and KECP.
Isolated TSRA may develop in south GA this evening, but the PoP at
KVLD and KABY is only 20%. Otherwise, VFR conditions are likely
outside of any isolated TSRA.
&&
.MARINE...
A low pressure system to our northwest will dip ito the SE US and
increase chances of showers and thunderstorms Thursday night and
Friday. Although most of the storms will be inland, some stronger
storms are expected, so there is the possibility of brief periods
of cautionary to advisory winds as these storms pass through.
Otherwise, winds and seas will remain below headline criteria
through the period.
&&
.FIRE WEATHER...
Red Flag conditions are not expected for the remainder of the work
week. Dispersion values may climb above 75 Thursday afternoon, from
a combination of strong vertical mixing and increasing winds aloft.
&&
.HYDROLOGY...
The Ochlockonee River at Thomasville is in action stage and may
rise slightly with rain tomorrow night, but it is not expected to
reach minor flood stage. MMEFS shows no sites are forecast to
reach flood stage in the near future. Although there is potential
for some severe thunderstorms Thursday night, WPC QPF for our area
is 0.25" or less and is not expected to cause significant rises on
area rivers.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 95 73 96 75 95 / 20 10 20 20 30
Panama City 90 76 91 78 92 / 30 10 10 20 20
Dothan 97 75 99 74 95 / 10 10 10 30 10
Albany 97 75 99 74 93 / 10 20 10 40 10
Valdosta 99 73 97 74 93 / 10 20 20 30 30
Cross City 93 72 92 73 92 / 20 10 20 20 30
Apalachicola 89 76 89 77 91 / 20 10 10 20 30
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Fournier
SHORT TERM...Moore
LONG TERM...Moore
AVIATION...Fournier
MARINE...Moore
FIRE WEATHER...Fournier
HYDROLOGY...Moore
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1104 AM EDT Wed Jun 12 2013
.DISCUSSION...
The 13 UTC regional surface analysis showed an area of high
pressure across much of the Gulf Coast, and a weak trough from the
GA coast through the FL Big Bend. Vapor imagery and upper air data
showed very dry air above 700mb, as our forecast area remains
under the dry, sinking northwest flow under the eastern periphery
of the central CONUS ridge.
The relatively warm, dry air aloft and large scale subsidence will
make it difficult for significant cumulus growth today, and the
MOS consensus PoP and Convection Allowing Models (CAM) PoP are 20%
or less for this afternoon. However, as was the case 24 hours ago,
the HRRR and 11 UTC local WRF are much more bullish in developing
deep moist convection. We`re discounting the local WRF, as its
boundary conditions (from the RAP) resulted in unrealistically high
surface moisture (i.e. dewpoints of around 80 deg). The HRRR, on
the other hand, did an outstanding job yesterday, so we have
subjectively blended in its solution with the other, drier NWP
guidance. The resulting PoP is nearly identical to what we had
yesterday, 20-30% from I-10 to the coast. While most updrafts
struggled to get any depth yesterday, a few storms did manage to
develop impressive hail cores. We think that will be case today,
as some of the CAM solutions have updraft speeds exceeding 20 m/s.
Of course the limited cloud cover will result in above-average
temperatures, with highs in the mid to upper 90s. Deep vertical
mixing will allow surface moisture to decrease a bit this
afternoon, so maximum heat index values will be around 105 deg.
&&
.AVIATION [through 12 UTC Thursday]...
Prevailing VFR conditions are expected through this TAF cycle.
Widely scattered TSRA will develop between 18 UTC and 00 UTC,
mainly between I-10 and the coast. Thus there is a slight chance
of TSRA at KTLH and KECP.
&&
.HYDROLOGY...
After the recent heavy rainfall across the area, two river points
are at or expected to reach Action Stage. The Ochlockonee River near
Thomasville is at Action stage, and will crest early Friday morning
then start to recede. The Little River near Hahira is expected to
reach Action Stage early Monday morning. With little precipitation
expected over the next couple of days, impacts to area rivers will
be minimal.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 95 72 96 74 / 20 10 20 20
Panama City 90 76 91 78 / 30 10 20 20
Dothan 97 74 99 74 / 10 10 10 20
Albany 97 74 99 74 / 10 20 10 30
Valdosta 97 72 99 73 / 10 10 20 30
Cross City 93 72 93 74 / 20 10 20 10
Apalachicola 89 75 89 77 / 30 10 10 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
GA...NONE.
FL...NONE.
GM...NONE.
&&
$$
HYDROLOGY...Navarro/Harrigan
REST OF DISCUSSION...Fournier
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
730 AM EDT WED JUN 12 2013
.AVIATION...
EARLY MORNING CONVECTION ACROSS THE ATLANTIC WATERS REMAINS NEARLY
STATIONARY AND IS EXPECTED TO REMAIN OFFSHORE THROUGH THE MORNING.
WINDS ARE EXPECTED TO BE LIGHT AND VARIABLE ACROSS THE AREA THROUGH
THE EARLY TO MID MORNING HOURS BEFORE TURNING MORE EASTERLY ACROSS
THE EAST COAST TERMINALS. FLOW WILL AGAIN BE RATHER WEAK ALLOWING
FOR GOOD CONVERGENCE WITH THE GULF BREEZE. EXPECT SCATTERED
SHRAS/TSRAS MAINLY ACROSS INTERIOR AREAS BUT COULD APPROACH ALL TAF
SITES LATE IN THE AFTERNOON. KEPT VCTS MENTION FOR NOW. ISOLATED IFR
CONDITIONS WILL BE POSSIBLE WITH ANY TSRA THAT AFFECTS ANY TAF SITE.
&&
.AVIATION...BNB/CD
.PREV DISCUSSION... /ISSUED 320 AM EDT WED JUN 12 2013/
SHORT TERM (TODAY-FRIDAY)...
THE LATEST MODEL GUIDANCE INDICATES THE UPPER LEVEL PATTERN BECOMING
MORE AMPLIFIED ACROSS THE COUNTRY BY THE END OF THE SHORT-TERM
PERIOD AS SEVERAL SHORTWAVE TROUGHS DIG SOUTHEAST FROM THE GREAT
LAKES TO THE SOUTHEAST AND AN UPPER RIDGE BUILDS OVER THE MID-WEST.
AT THE SURFACE...THE LOCAL AREA WILL REMAIN IN A WEAKNESS WITHIN THE
SUBTROPICAL RIDGE WITH WEAK LOW-LEVEL STEERING FLOW CONTINUING. A
WEAK FRONTAL BOUNDARY ASSOCIATED WITH A SHORTWAVE TROUGH IS FORECAST
TO SAG SOUTH OVER THE STATE BY THE END OF THE PERIOD.
FOR TODAY...THE WEAK LOW-LEVEL FLOW COMBINED WITH A SUFFICIENT
AMOUNT OF MOISTURE AND INCREASING INSTABILITY DUE TO COOLER
MID/UPPER LEVEL TEMPERATURES (H5 -10 C INLAND) SPREADING SOUTH OVER
THE AREA WILL LIKELY TRANSLATE TO ANOTHER ROUND OF SCATTERED SHOWERS
AND STORMS THIS AFTERNOON. A FEW OF THESE STORMS MAY BECOME STRONG
WITH THE MAIN THREATS BEING GUSTY WINDS AND HAIL.
ADDITIONALLY...WITH THE WEAK STEERING FLOW IN PLACE AND VERY
LITTLE STORM MOTION WITH THE ACTIVITY THAT DOES DEVELOP COULD LEAD
TO LOCALIZED FLOODING. ALTHOUGH THE HI-RES MODEL REFLECTIVITIES
DISPLAY QUITE THE SPREAD AS TO WHERE THE AFTERNOON CONVECTION WILL
BECOME CONCENTRATED...THE MORE RELIABLE HRRR SOLUTION GENERALLY
INDICATES THE BULK OF THIS ACTIVITY SETTING UP OVER THE INTERIOR
AREAS BEGINNING AROUND 16-19Z.
THURSDAY THROUGH FRIDAY...ALTHOUGH SIMILAR CONDITIONS WILL
PERSIST...MID-LEVEL TEMPERATURES ARE FORECAST TO WARM BACK TO AROUND
OR JUST ABOVE AVERAGE. PRECIPITABLE WATER VALUES ARE ALSO FORECAST
TO TREND DOWNWARD TOWARD 1.5". THE SFC RIDGE IS FORECAST TO STEADILY
SHIFT SOUTHWARD...WHICH WILL LEAD TO LIGHT SWRLY LOW-LEVEL FLOW
AHEAD OF THE AFOREMENTIONED FRONTAL BOUNDARY SAGGING SOUTH INTO THE
STATE BY FRIDAY AFTERNOON. DESPITE THE MORE STABLE AND SLIGHTLY
DRIER CONDITIONS...AFTERNOON SHOWERS/TSTMS...MAINLY ISOLATED IN
COVERAGE...MAY FAVOR THE EAST COAST METRO AREAS WITH THE SW FLOW
SETTING UP THROUGH THIS TIME.
LONG TERM (FRIDAY NIGHT-TUESDAY)...
THE MODELS GENERALLY INDICATE RISING UPPER HEIGHTS ALONG WITH SOME
DRIER MID/UPPER AIR OVER THE WEEKEND. HIGH PRESSURE BUILDING EAST
NORTH OF THE AREA IN THE WAKE OF THE PREVIOUSLY DISCUSSED FRONTAL
BOUNDARY WILL LEAD TO EASTERLY LOW-LEVEL FLOW RETURNING ACROSS THE
AREA. PRECIPITABLE WATER VALUES ARE FORECAST TO DIP DOWN BELOW 1.25"
THROUGH THE WEEKEND AND INTO MONDAY. THIS WILL LEAD TO DRIER AND
WARMER CONDITIONS ACROSS THE AREA. ANY AFTERNOON SHOWERS THAT
DEVELOP SHOULD REMAIN INLAND WITH THE EASTERLY FLOW SETTING UP.
AVIATION...
WINDS ARE EXPECTED TO BE LIGHT AND VARIABLE ACROSS THE AREA THROUGH
THE EARLY TO MID MORNING HOURS BEFORE TURNING MORE EASTERLY ACROSS
THE EAST COAST TERMINALS. FLOW WILL AGAIN BE RATHER WEAK ALLOWING
FOR GOOD CONVERGENCE WITH THE GULF BREEZE. EXPECT SCATTERED
SHRAS/TSRAS MAINLY ACROSS INTERIOR AREAS BUT COULD APPROACH ALL TAF
SITES LATE IN THE AFTERNOON. KEPT VCTS MENTION FOR NOW. ISOLATED IFR
CONDITIONS WILL BE POSSIBLE WITH ANY TSRA THAT AFFECTS ANY TAF SITE.
MARINE...
HIGH PRESSURE RIDGE WILL STEADILY SHIFT SOUTH OVER THE MARINE AREA
THROUGH THE END OF THE WEEK AS A WEAK FRONTAL BOUNDARY APPROACHES
FROM THE NORTH. AS A RESULT...LIGHT WINDS AND LOW SEAS WILL BE
EXPECTED TO CONTINUE.
FIRE WEATHER...
PLENTY OF MOISTURE WILL KEEP THE RH VALUES WELL ABOVE CRITICAL
LEVELS EACH DAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 89 76 89 76 / 20 20 20 20
FORT LAUDERDALE 88 77 89 76 / 20 20 20 20
MIAMI 89 77 90 75 / 20 20 20 20
NAPLES 89 74 88 74 / 20 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
442 AM EDT Wed Jun 12 2013
.NEAR TERM [Through Tonight]...
With upper level ridging continuing to nose in from the west, SFC
ridging parked just to our south, and NW synoptic flow at the lower
levels, plenty of daytime insolation should allow for one of the
hottest days of the season thus far. High temps are expected to
climb into the upper 90s over much of the interior, with lower 90s
restricted to the immediate coast. In fact, the usual hot spots like
Valdosta may experience their first 100 degree day this year. Heat
indices will also be on the rise, but afternoon dewpoints should mix
out enough to keep them below Advisory levels. Nevertheless,
maximum Heat Indices of around 105 degrees will be quite
uncomfortable. As for rain chances, the 1000-700mb Mean Layer Vector
Wind (MLVW) will be out of the NW today, which is a Type 8 Regime in
our local Sea Breeze Climatology (reference
www.srh.noaa.gov/tae/?n=seabreeze for details). In short, this
Regime tends to keep the Sea Breeze Front pinned near the coastline
until later in the afternoon, but also increases vertical motion
along the front, which can result in stronger storms given a
favorable environment. For this afternoon, we are only forecasting
20% PoPs across much of the FL Big Bend and Panhandle (with silent
10s elsewhere), which is essentially a blend of our local Confidence
Grids and CAM (Convective Allowing Models) output. These PoPs are
also lower than a typical Type 8 Regime due to less favorable deep
layer thermodynamics. However, any storms that do develop may
contain brief gusty winds. For tonight, did not carry over any PoPs
at this time, although this always carries some risk in Regime 8 due
to the usual late start of the convection. Additionally, some of the
Hi-Res models are hinting at potential MCS development to our N and
NE which will have to be monitored as well.
&&
.SHORT TERM [Thursday Through Friday Night]...
The main focus for the short term period will be the potential for
severe weather in our CWA. The SPC Day 2 Outlook has our far
northern Florida counties and all of our Georgia and Alabama
counties under a slight risk, but our entire CWA is under at least
a 5% probability of severe weather.
Deep layer ridging to the west and troughing to the east will
continue to keep our CWA in a northwest flow regime. Northwest
flow will keep our entire CWA drier than average and warmer than
average. A shortwave is expected round the base of the trough and
pivot through our area beginning Friday morning. This type of
synoptic pattern is conducive for MCS development/maintenance. Low
level CAPE and shear values seem conducive for new cell
development to maintain multicellular thunderstorm complexes. The
advancing afternoon sea breeze of Friday will also likely enhance
any thunderstorms that are present.
Other than the chance for severe weather the remaining short term
period will be characterized by above average temperatures, below
averages humidities, and low chances for rain.
&&
.LONG TERM [Saturday through Wednesday]...
Continuing from the short term, we have a frontal system possibly
reaching our area around Thursday night and exiting to the southeast
by overnight Friday night. Rain chances will stay low once again
thanks to high pressure aloft and at the surface, although some
convection from the sea-breeze may be possible. Monday through
Tuesday rain chances increase again as another shortwave moves
through with a similar setup to the Thursday-Friday rain chances.
Highs in the 90s and lows in the 70s are expected through the period.
&&
.AVIATION...
[Through 12 UTC Thursday] With the recent influx of drier air from
the northwest, VFR conditions should prevail at the terminals
through the period. However, did go with brief periods of low end
MVFR Cigs at ECP and TLH (based on input from the HRRR guidance)
overnight and a period of MVFR level Vis at VLD. During the day,
isolated afternoon thunderstorms will again be possible with the Sea
Breeze Front, but PoPs are too low for mention in any of the Tafs at
this time. That said, with the northwesterly flow, the best chances
for an afternoon storm would be at ECP and TLH.
&&
.MARINE...
Light winds and relatively calm seas are expected until a frontal
system approaches to our north beginning late Thursday night/early
Friday morning when cautionary levels will be possible. By Friday
night, winds are expected to weaken to below cautionary levels.
&&
.FIRE WEATHER...
Although the generally hot and dry weather will continue, conditions
are not expected to approach Red Flag levels over the next several
days.
&&
.HYDROLOGY...
After the recent heavy rainfall across the area, two river points
are at or expected to reach Action Stage. The Ochlockonee River near
Thomasville is at Action stage, and will crest early Friday morning
then start to recede. The Little River near Hahira is expected to
reach Action Stage early Monday morning. With little precipitation
expected over the next couple of days, impacts to area rivers will
be minimal.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 98 72 96 74 94 / 20 10 20 20 30
Panama City 92 76 91 78 91 / 20 10 20 20 30
Dothan 98 74 99 74 95 / 10 10 10 20 20
Albany 98 74 99 74 93 / 10 10 10 30 20
Valdosta 100 72 99 73 92 / 10 10 20 30 30
Cross City 95 72 93 74 91 / 20 10 20 10 30
Apalachicola 91 75 89 77 90 / 20 10 10 10 30
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Gould
SHORT TERM...Navarro/Harrigan
LONG TERM...Moore
AVIATION...Gould
MARINE...Navarro/Harrigan
FIRE WEATHER...Navarro/Harrigan
HYDROLOGY...Navarro/Harrigan
AREA FORECAST DISCUSSION
NWS MIAMI FL
320 AM EDT WED JUN 12 2013
.SHORT TERM (TODAY-FRIDAY)...
THE LATEST MODEL GUIDANCE INDICATES THE UPPER LEVEL PATTERN BECOMING
MORE AMPLIFIED ACROSS THE COUNTRY BY THE END OF THE SHORT-TERM
PERIOD AS SEVERAL SHORTWAVE TROUGHS DIG SOUTHEAST FROM THE GREAT
LAKES TO THE SOUTHEAST AND AN UPPER RIDGE BUILDS OVER THE MID-WEST.
AT THE SURFACE...THE LOCAL AREA WILL REMAIN IN A WEAKNESS WITHIN THE
SUBTROPICAL RIDGE WITH WEAK LOW-LEVEL STEERING FLOW CONTINUING. A
WEAK FRONTAL BOUNDARY ASSOCIATED WITH A SHORTWAVE TROUGH IS FORECAST
TO SAG SOUTH OVER THE STATE BY THE END OF THE PERIOD.
FOR TODAY...THE WEAK LOW-LEVEL FLOW COMBINED WITH A SUFFICIENT
AMOUNT OF MOISTURE AND INCREASING INSTABILITY DUE TO COOLER
MID/UPPER LEVEL TEMPERATURES (H5 -10 C INLAND) SPREADING SOUTH OVER
THE AREA WILL LIKELY TRANSLATE TO ANOTHER ROUND OF SCATTERED SHOWERS
AND STORMS THIS AFTERNOON. A FEW OF THESE STORMS MAY BECOME STRONG
WITH THE MAIN THREATS BEING GUSTY WINDS AND HAIL.
ADDITIONALLY...WITH THE WEAK STEERING FLOW IN PLACE AND VERY
LITTLE STORM MOTION WITH THE ACTIVITY THAT DOES DEVELOP COULD LEAD
TO LOCALIZED FLOODING. ALTHOUGH THE HI-RES MODEL REFLECTIVITIES
DISPLAY QUITE THE SPREAD AS TO WHERE THE AFTERNOON CONVECTION WILL
BECOME CONCENTRATED...THE MORE RELIABLE HRRR SOLUTION GENERALLY
INDICATES THE BULK OF THIS ACTIVITY SETTING UP OVER THE INTERIOR
AREAS BEGINNING AROUND 16-19Z.
THURSDAY THROUGH FRIDAY...ALTHOUGH SIMILAR CONDITIONS WILL
PERSIST...MID-LEVEL TEMPERATURES ARE FORECAST TO WARM BACK TO AROUND
OR JUST ABOVE AVERAGE. PRECIPITABLE WATER VALUES ARE ALSO FORECAST
TO TREND DOWNWARD TOWARD 1.5". THE SFC RIDGE IS FORECAST TO STEADILY
SHIFT SOUTHWARD...WHICH WILL LEAD TO LIGHT SWRLY LOW-LEVEL FLOW
AHEAD OF THE AFOREMENTIONED FRONTAL BOUNDARY SAGGING SOUTH INTO THE
STATE BY FRIDAY AFTERNOON. DESPITE THE MORE STABLE AND SLIGHTLY
DRIER CONDITIONS...AFTERNOON SHOWERS/TSTMS...MAINLY ISOLATED IN
COVERAGE...MAY FAVOR THE EAST COAST METRO AREAS WITH THE SW FLOW
SETTING UP THROUGH THIS TIME.
.LONG TERM (FRIDAY NIGHT-TUESDAY)...
THE MODELS GENERALLY INDICATE RISING UPPER HEIGHTS ALONG WITH SOME
DRIER MID/UPPER AIR OVER THE WEEKEND. HIGH PRESSURE BUILDING EAST
NORTH OF THE AREA IN THE WAKE OF THE PREVIOUSLY DISCUSSED FRONTAL
BOUNDARY WILL LEAD TO EASTERLY LOW-LEVEL FLOW RETURNING ACROSS THE
AREA. PRECIPITABLE WATER VALUES ARE FORECAST TO DIP DOWN BELOW 1.25"
THROUGH THE WEEKEND AND INTO MONDAY. THIS WILL LEAD TO DRIER AND
WARMER CONDITIONS ACROSS THE AREA. ANY AFTERNOON SHOWERS THAT
DEVELOP SHOULD REMAIN INLAND WITH THE EASTERLY FLOW SETTING UP.
&&
.AVIATION...
WINDS ARE EXPECTED TO BE LIGHT AND VARIABLE ACROSS THE AREA THROUGH
THE EARLY TO MID MORNING HOURS BEFORE TURNING MORE EASTERLY ACROSS
THE EAST COAST TERMINALS. FLOW WILL AGAIN BE RATHER WEAK ALLOWING
FOR GOOD CONVERGENCE WITH THE GULF BREEZE. EXPECT SCATTERED
SHRAS/TSRAS MAINLY ACROSS INTERIOR AREAS BUT COULD APPROACH ALL TAF
SITES LATE IN THE AFTERNOON. KEPT VCTS MENTION FOR NOW. ISOLATED IFR
CONDITIONS WILL BE POSSIBLE WITH ANY TSRA THAT AFFECTS ANY TAF SITE.
&&
.MARINE...
HIGH PRESSURE RIDGE WILL STEADILY SHIFT SOUTH OVER THE MARINE AREA
THROUGH THE END OF THE WEEK AS A WEAK FRONTAL BOUNDARY APPROACHES
FROM THE NORTH. AS A RESULT...LIGHT WINDS AND LOW SEAS WILL BE
EXPECTED TO CONTINUE.
&&
.FIRE WEATHER...
PLENTY OF MOISTURE WILL KEEP THE RH VALUES WELL ABOVE CRITICAL
LEVELS EACH DAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 89 76 89 76 / 20 20 20 20
FORT LAUDERDALE 88 77 89 76 / 20 20 20 20
MIAMI 89 77 90 75 / 20 20 20 20
NAPLES 89 74 88 74 / 20 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
155 PM EDT WED JUN 12 2013
.UPDATE...
I HAVE ADJUSTED SOME OF THE GRIDS FOR TODAY...MAINLY POPS/WEATHER.
MODEL SOUNDINGS HAVE BEEN INDICATING THAT THE MID-LEVEL CAP WOULD
REMAIN STRONGLY IN PLACE OVER NORTH AND CENTRAL GEORGIA THROUGH
TODAY. THE 12Z SOUNDING FROM KFFC SHOWS THE MID-LEVEL CAP TO BE
SIGNIFICANTLY WEAKER THAN EXPECTED WITH ONLY MINIMAL CIN IN THE
VICINITY OF THE LFC. STILL...WE ARE UNDER THE EASTERN EDGE OF THE
UPPER-LEVEL RIDGE AND SOME INHIBITION WILL LIKELY CONTINUE THROUGH
TODAY. IF ANY STORMS MANAGE TO BREAK THROUGH THIS AFTERNOON...
INSTABILITY IS MODERATE WITH CAPE AROUND 2000 J/KG AND LI/S IN THE -4
TO -6 DEGREE RANGE SO AN ISOLATED STRONG STORM OR TWO WOULD NOT BE
IMPOSSIBLE. NO SIGNIFICANT CHANGES MADE TO THE REMAINDER OF THE GRIDS
AS CURRENT FORECAST TRENDS LOOK PRETTY GOOD.
&&
.PREV DISCUSSION... /ISSUED 733 AM EDT WED JUN 12 2013/
PREV DISCUSSION...
SHORT TERM /TODAY THROUGH THURSDAY/...
/ISSUED 405 AM EDT WED JUN 12 2013/
ANOTHER HOT DAY ACROSS THE CWA AS THE AREA REMAINS UNDER THE EASTERN
EDGE OF AN UPPER LEVEL RIDGE. SOME DECENT UNCERTAINTY IN THE POP
FORECAST FOR TODAY. GFS SHOWS A STRONG VORT MAX ROUNDING THE UPPER
LEVEL RIDGE AND BRINGS IT INTO NORTH GEORGIA BY MID MORNING. GFS
ISNT GENERATING MUCH IN TERMS OF PRECIP WITH IT THOUGH ACROSS THE
CWA. NAM SHOWS SOME REFLECTION OF A SHORTWAVE BUT IS WEAKER AND
GENERALLY FURTHER EAST. EVEN HARDER TO PICK OUT THE FEATURE IN THE
ECMWF. DESPITE THIS THOUGH...ECMWF AND NAM ARE THE HIGHEST IN TERMS
OF PRECIP CHANCES ACROSS NORTH GEORGIA TODAY. HRRR IS PICKING UP ON
SOME ACTIVITY IN NORTH GEORGIA ASSOCIATED WITH THIS. FOR THE
FORECAST TRIED TO MEET IN THE MIDDLE AND HAVE SHOWN SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS THE NORTH. LEE SIDE TROUGH APPEARS
IT SHOULD BE JUST SOUTH OF THE CWA THIS AFTERNOON AND IF SOMETHING
WERE TO DEVELOP...THINK IT SHOULD BE ALONG THIS BOUNDARY...SO KEPT
MENTION OF POPS OUT OF CENTRAL GEORGIA.
THURSDAY IS THE BETTER CHANCE OF RAIN IN THE SHORT TERM AS A STRONG
SHORTWAVE MOVES FROM THE OHIO VALLEY INTO THE MID ATLANTIC AND A
COLD FRONT MOVES INTO GEORGIA. MODELS ARE IN GOOD AGREEMENT WITH THE
COLD FRONT MOVING INTO THE NORTH THURSDAY MORNING AND INTO CENTRAL
GEORGIA BY THE EVENING. DECENT INSTABILITY WITH THE SYSTEM WITH THE
GFS SHOWING ML CAPE AROUND 2000 J/KG. LL SHEAR IS NON-ZERO WITH
AROUND 20KTS ACROSS CENTRAL GEORGIA. WITH THE INSTABILITY...A
BOUNDARY TO FOCUS ON AND UPPER LEVEL SUPPORT...ISOLD SEVERE STORMS
ARE POSSIBLE ON THURSDAY WITH THE MAIN THREATS BEING WIND AND HAIL.
TOTAL RAINFALL AMOUNTS SHOULD BE MINIMAL...AROUND A QUARTER INCH OR
LESS WITH LOCALLY HIGHER AMOUNTS IN SOME OF THE THUNDERSTORMS.
BOTH AHN AND ATL SAW THEIR FIRST 90 DEGREE DAY FOR THE YEAR
YESTERDAY AND ALL OF NORTH AND CENTRAL GEORGIA IS EXPECTED TO REACH
THE LOW TO MID 90S AGAIN TODAY EXCEPT FOR THE MOUNTAINS. EVEN WITH
THE FRONT EXPECTED ON THURSDAY...MOST PLACES WILL HAVE TIME AHEAD OF
THE RAIN TO REACH THE 90S AGAIN. SOME OF CENTRAL GEORGIA WILL REACH
HEAT INDICES OF 100-102 THIS AFTERNOON WHICH FALLS SHORT OF A HEAT
ADVISORY /105 DEGREES OR GREATER HEAT INDICES FOR TWO CONSECUTIVE
DAYS/...BUT IT WILL STILL BE HOT AND FOLKS SHOULD KEEP THIS IN MIND
WHEN WORKING OUTSIDE AS ITS EXPECTED TO BE THE HOTTEST DAY OF THE
SEASON SO FAR.
11
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
/ISSUED 405 AM EDT WED JUN 12 2013/
A COLD FRONT WILL BE CLOSE TO CENTRAL GA AND MOVING S STARTING
THURSDAY NIGHT WITH POTENTIAL FOR SEVERE STORMS ASSOCIATED. THE
FRONT EXITS THE FORECAST AREA LATER THURSDAY NIGHT WITH THE GFS THE
FASTEST...THE NAM NEXT AND THE EUROPEAN THE SLOWEST.
PRECIP CHANCES MOST LIKELY WILL HAVE ENDED FOR FRIDAY ALTHOUGH THE
EUROPEAN HOLDS ONTO CHANCES OVER CENTRAL GA. SATURDAY IS DRY AS HIGH
PRESSURE ALOFT OVER THE LOWER MS VALLEY HELPS FOR HOLD ANY
CONVECTION AT BAY...HOWEVER NW FLOW ALOFT IS OVER THE AREA BUT
APPEARS TO HAVE ONLY MINIMAL MOISTURE. SUNDAY APPEARS ONE OF THOSE
DAYS WHERE YOU COULD GO EITHER WAY WITH 20 PERCENT POPS OVER THE NW
HALF OR SO OF THE AREA AS THE UPPER RIDGE FLATTENS AND SOME
INSTABILITY DEVELOPS WITH MINIMAL MOISTURE. FOR NOW WILL JUST HOLD
ONTO 10 PERCENT ACROSS THE NW. THE SOUTHERN EDGE OF THE WESTERLIES
RETURN FOR MONDAY AND TUESDAY WITH INCREASED MOISTURE AND
INSTABILITY ACROSS THE AREA AND THE POSSIBILITY FOR SHORT WAVES TO
ENHANCE THE POTENTIAL FOR SCATTERED SHOWERS AND THUNDERSTORMS. A
WEAK COLD FRONT MAY GET INTO N GA FOR WEDNESDAY.
BDL
&&
AVIATION...
18Z UPDATE...
VFR CONDITIONS SHOULD PREDOMINATE THROUGH THIS FORECAST PERIOD
OUTSIDE OF ISOLATED TO SCATTERED CONVECTIVE ACTIVITY. SCATTERED
AREAS OF MVFR...WITH LOCAL IFR...VISIBILITIES ARE EXPECTED AGAIN
THURSDAY MORNING BETWEEN 06Z AND 14Z. THE ONLY TAF SITE WHERE I AM
CARRYING ANY SUB-VFR CONDITIONS IS KAHN. ISOLATED TO SCATTERED...
MAINLY DIURNALLY DRIVEN...CONVECTION IS EXPECTED THIS AFTERNOON INTO
THE EVENING. HOWEVER THE CHANCES FOR THUNDER AT ANY INDIVIDUAL TAF
SITE IS TOO LOW AT THIS POINT TO INCLUDE IN THE TAFS. WILL CONTINUE
TO WATCH AND AMEND FOR ANY SPECIFIC THREATS TO INDIVIDUAL TAF
AIRFIELDS. BETTER CHANCES FOR THUNDERSTORMS MOVE IN THURSDAY IN
ADVANCE OF AN APPROACHING COLD FRONT...BUT MAINLY AFTER THE END OF
THIS FORECAST PERIOD. WINDS WILL REMAIN WESTERLY MAINLY AT 7KT OR
LESS THROUGH 12Z...INCREASING TO 10-14KT BY 16Z WITH GUSTS 18-24KT.
//ATL CONFIDENCE...12Z UPDATE...
HIGH CONFIDENCE ON CIGS...VSBY AND WINDS. MEDIUM CONFIDENCE ON
CONVECTIVE TRENDS.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 95 70 94 67 / 30 30 50 20
ATLANTA 92 74 92 68 / 30 30 50 30
BLAIRSVILLE 88 67 86 59 / 30 30 50 20
CARTERSVILLE 93 70 93 65 / 30 30 50 20
COLUMBUS 95 75 96 73 / 30 30 20 40
GAINESVILLE 91 72 91 66 / 30 30 50 20
MACON 95 71 96 69 / 30 30 20 40
ROME 94 70 92 66 / 30 30 50 10
PEACHTREE CITY 92 69 93 67 / 30 30 50 30
VIDALIA 96 75 97 73 / 30 30 20 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...20
LONG TERM....TDP
AVIATION...20
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1034 AM EDT WED JUN 12 2013
.UPDATE...
I HAVE ADJUSTED SOME OF THE GRIDS FOR TODAY...MAINLY POPS/WEATHER.
MODEL SOUNDINGS HAVE BEEN INDICATING THAT THE MID-LEVEL CAP WOULD
REMAIN STRONGLY IN PLACE OVER NORTH AND CENTRAL GEORGIA THROUGH
TODAY. THE 12Z SOUNDING FROM KFFC SHOWS THE MID-LEVEL CAP TO BE
SIGNIFICANTLY WEAKER THAN EXPECTED WITH ONLY MINIMAL CIN IN THE
VICINITY OF THE LFC. STILL...WE ARE UNDER THE EASTERN EDGE OF THE
UPPER-LEVEL RIDGE AND SOME INHIBITION WILL LIKELY CONTINUE THROUGH
TODAY. IF ANY STORMS MANAGE TO BREAK THROUGH THIS AFTERNOON...
INSTABILITY IS MODERATE WITH CAPE AROUND 2000 J/KG AND LI/S IN THE -4
TO -6 DEGREE RANGE SO AN ISOLATED STRONG STORM OR TWO WOULD NOT BE
IMPOSSIBLE. NO SIGNIFICANT CHANGES MADE TO THE REMAINDER OF THE GRIDS
AS CURRENT FORECAST TRENDS LOOK PRETTY GOOD.
&&
.PREV DISCUSSION... /ISSUED 733 AM EDT WED JUN 12 2013/
PREV DISCUSSION...
SHORT TERM /TODAY THROUGH THURSDAY/...
/ISSUED 405 AM EDT WED JUN 12 2013/
ANOTHER HOT DAY ACROSS THE CWA AS THE AREA REMAINS UNDER THE EASTERN
EDGE OF AN UPPER LEVEL RIDGE. SOME DECENT UNCERTAINTY IN THE POP
FORECAST FOR TODAY. GFS SHOWS A STRONG VORT MAX ROUNDING THE UPPER
LEVEL RIDGE AND BRINGS IT INTO NORTH GEORGIA BY MID MORNING. GFS
ISNT GENERATING MUCH IN TERMS OF PRECIP WITH IT THOUGH ACROSS THE
CWA. NAM SHOWS SOME REFLECTION OF A SHORTWAVE BUT IS WEAKER AND
GENERALLY FURTHER EAST. EVEN HARDER TO PICK OUT THE FEATURE IN THE
ECMWF. DESPITE THIS THOUGH...ECMWF AND NAM ARE THE HIGHEST IN TERMS
OF PRECIP CHANCES ACROSS NORTH GEORGIA TODAY. HRRR IS PICKING UP ON
SOME ACTIVITY IN NORTH GEORGIA ASSOCIATED WITH THIS. FOR THE
FORECAST TRIED TO MEET IN THE MIDDLE AND HAVE SHOWN SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS THE NORTH. LEE SIDE TROUGH APPEARS
IT SHOULD BE JUST SOUTH OF THE CWA THIS AFTERNOON AND IF SOMETHING
WERE TO DEVELOP...THINK IT SHOULD BE ALONG THIS BOUNDARY...SO KEPT
MENTION OF POPS OUT OF CENTRAL GEORGIA.
THURSDAY IS THE BETTER CHANCE OF RAIN IN THE SHORT TERM AS A STRONG
SHORTWAVE MOVES FROM THE OHIO VALLEY INTO THE MID ATLANTIC AND A
COLD FRONT MOVES INTO GEORGIA. MODELS ARE IN GOOD AGREEMENT WITH THE
COLD FRONT MOVING INTO THE NORTH THURSDAY MORNING AND INTO CENTRAL
GEORGIA BY THE EVENING. DECENT INSTABILITY WITH THE SYSTEM WITH THE
GFS SHOWING ML CAPE AROUND 2000 J/KG. LL SHEAR IS NON-ZERO WITH
AROUND 20KTS ACROSS CENTRAL GEORGIA. WITH THE INSTABILITY...A
BOUNDARY TO FOCUS ON AND UPPER LEVEL SUPPORT...ISOLD SEVERE STORMS
ARE POSSIBLE ON THURSDAY WITH THE MAIN THREATS BEING WIND AND HAIL.
TOTAL RAINFALL AMOUNTS SHOULD BE MINIMAL...AROUND A QUARTER INCH OR
LESS WITH LOCALLY HIGHER AMOUNTS IN SOME OF THE THUNDERSTORMS.
BOTH AHN AND ATL SAW THEIR FIRST 90 DEGREE DAY FOR THE YEAR
YESTERDAY AND ALL OF NORTH AND CENTRAL GEORGIA IS EXPECTED TO REACH
THE LOW TO MID 90S AGAIN TODAY EXCEPT FOR THE MOUNTAINS. EVEN WITH
THE FRONT EXPECTED ON THURSDAY...MOST PLACES WILL HAVE TIME AHEAD OF
THE RAIN TO REACH THE 90S AGAIN. SOME OF CENTRAL GEORGIA WILL REACH
HEAT INDICES OF 100-102 THIS AFTERNOON WHICH FALLS SHORT OF A HEAT
ADVISORY /105 DEGREES OR GREATER HEAT INDICES FOR TWO CONSECUTIVE
DAYS/...BUT IT WILL STILL BE HOT AND FOLKS SHOULD KEEP THIS IN MIND
WHEN WORKING OUTSIDE AS ITS EXPECTED TO BE THE HOTTEST DAY OF THE
SEASON SO FAR.
11
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
/ISSUED 405 AM EDT WED JUN 12 2013/
A COLD FRONT WILL BE CLOSE TO CENTRAL GA AND MOVING S STARTING
THURSDAY NIGHT WITH POTENTIAL FOR SEVERE STORMS ASSOCIATED. THE
FRONT EXITS THE FORECAST AREA LATER THURSDAY NIGHT WITH THE GFS THE
FASTEST...THE NAM NEXT AND THE EUROPEAN THE SLOWEST.
PRECIP CHANCES MOST LIKELY WILL HAVE ENDED FOR FRIDAY ALTHOUGH THE
EUROPEAN HOLDS ONTO CHANCES OVER CENTRAL GA. SATURDAY IS DRY AS HIGH
PRESSURE ALOFT OVER THE LOWER MS VALLEY HELPS FOR HOLD ANY
CONVECTION AT BAY...HOWEVER NW FLOW ALOFT IS OVER THE AREA BUT
APPEARS TO HAVE ONLY MINIMAL MOISTURE. SUNDAY APPEARS ONE OF THOSE
DAYS WHERE YOU COULD GO EITHER WAY WITH 20 PERCENT POPS OVER THE NW
HALF OR SO OF THE AREA AS THE UPPER RIDGE FLATTENS AND SOME
INSTABILITY DEVELOPS WITH MINIMAL MOISTURE. FOR NOW WILL JUST HOLD
ONTO 10 PERCENT ACROSS THE NW. THE SOUTHERN EDGE OF THE WESTERLIES
RETURN FOR MONDAY AND TUESDAY WITH INCREASED MOISTURE AND INSTABILITY
ACROSS THE AREA AND THE POSSIBILITY FOR SHORT WAVES TO ENHANCE THE
POTENTIAL FOR SCATTERED SHOWERS AND THUNDERSTORMS. A WEAK COLD FRONT
MAY GET INTO N GA FOR WEDNESDAY.
BDL
AVIATION...
12Z UPDATE...
EXCEPT FOR SOME MVFR VSBYS THIS MORNING DUE TO FOG...VFR
CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. BIGGEST
UNCERTAINTY IS IN REGARDS TO THE PRECIPITATION FORECAST FOR TODAY.
HAVE A DISTURBANCE ROUNDING THE EDGE OF THE UPPER RIDGE AND MODELS
DIFFER ON IF CONVECTION WILL MOVE INTO GEORGIA. FOR NOW...THINKING
IS ANY CONVECTION THAT DEVELOPS WILL REMAIN NORTH AND EAST OF THE
TERMINALS. OF ALL THE SITES THOUGH...AHN AGAIN WOULD BE MOST
LIKELY TO SEE AN ISOLD THUNDERSTORM. OVERALL SHOULD SEE NW
WINDS...HOWEVER ONE MODEL IS PICKING UP AT A BRIEF PERIOD OF NE
AND THUS THE REASON FOR MEDIUM CONFIDENCE ON WINDS.
//ATL CONFIDENCE...12Z UPDATE...
HIGH CONFIDENCE ON CIGS AND VSBYS. MEDIUM CONFIDENCE ON WINDS.
MEDIUM CONFIDENCE ON ISOLD CONVECTION STAYING OUT OF THE
TERMINAL.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 95 70 94 67 / 30 30 50 20
ATLANTA 92 74 92 68 / 30 30 50 30
BLAIRSVILLE 88 67 86 59 / 30 30 50 20
CARTERSVILLE 93 70 93 65 / 30 30 50 20
COLUMBUS 95 75 96 73 / 30 30 20 40
GAINESVILLE 91 72 91 66 / 30 30 50 20
MACON 95 71 96 69 / 30 30 20 40
ROME 94 70 92 66 / 30 30 50 10
PEACHTREE CITY 92 69 93 67 / 30 30 50 30
VIDALIA 96 75 97 73 / 30 30 20 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...20
LONG TERM....TDP
AVIATION...20
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
733 AM EDT WED JUN 12 2013
.PREV DISCUSSION...
SHORT TERM /TODAY THROUGH THURSDAY/...
/ISSUED 405 AM EDT WED JUN 12 2013/
ANOTHER HOT DAY ACROSS THE CWA AS THE AREA REMAINS UNDER THE EASTERN
EDGE OF AN UPPER LEVEL RIDGE. SOME DECENT UNCERTAINTY IN THE POP
FORECAST FOR TODAY. GFS SHOWS A STRONG VORT MAX ROUNDING THE UPPER
LEVEL RIDGE AND BRINGS IT INTO NORTH GEORGIA BY MID MORNING. GFS
ISNT GENERATING MUCH IN TERMS OF PRECIP WITH IT THOUGH ACROSS THE
CWA. NAM SHOWS SOME REFLECTION OF A SHORTWAVE BUT IS WEAKER AND
GENERALLY FURTHER EAST. EVEN HARDER TO PICK OUT THE FEATURE IN THE
ECMWF. DESPITE THIS THOUGH...ECMWF AND NAM ARE THE HIGHEST IN TERMS
OF PRECIP CHANCES ACROSS NORTH GEORGIA TODAY. HRRR IS PICKING UP ON
SOME ACTIVITY IN NORTH GEORGIA ASSOCIATED WITH THIS. FOR THE
FORECAST TRIED TO MEET IN THE MIDDLE AND HAVE SHOWN SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS THE NORTH. LEE SIDE TROUGH APPEARS
IT SHOULD BE JUST SOUTH OF THE CWA THIS AFTERNOON AND IF SOMETHING
WERE TO DEVELOP...THINK IT SHOULD BE ALONG THIS BOUNDARY...SO KEPT
MENTION OF POPS OUT OF CENTRAL GEORGIA.
THURSDAY IS THE BETTER CHANCE OF RAIN IN THE SHORT TERM AS A STRONG
SHORTWAVE MOVES FROM THE OHIO VALLEY INTO THE MID ATLANTIC AND A
COLD FRONT MOVES INTO GEORGIA. MODELS ARE IN GOOD AGREEMENT WITH THE
COLD FRONT MOVING INTO THE NORTH THURSDAY MORNING AND INTO CENTRAL
GEORGIA BY THE EVENING. DECENT INSTABILITY WITH THE SYSTEM WITH THE
GFS SHOWING ML CAPE AROUND 2000 J/KG. LL SHEAR IS NON-ZERO WITH
AROUND 20KTS ACROSS CENTRAL GEORGIA. WITH THE INSTABILITY...A
BOUNDARY TO FOCUS ON AND UPPER LEVEL SUPPORT...ISOLD SEVERE STORMS
ARE POSSIBLE ON THURSDAY WITH THE MAIN THREATS BEING WIND AND HAIL.
TOTAL RAINFALL AMOUNTS SHOULD BE MINIMAL...AROUND A QUARTER INCH OR
LESS WITH LOCALLY HIGHER AMOUNTS IN SOME OF THE THUNDERSTORMS.
BOTH AHN AND ATL SAW THEIR FIRST 90 DEGREE DAY FOR THE YEAR
YESTERDAY AND ALL OF NORTH AND CENTRAL GEORGIA IS EXPECTED TO REACH
THE LOW TO MID 90S AGAIN TODAY EXCEPT FOR THE MOUNTAINS. EVEN WITH
THE FRONT EXPECTED ON THURSDAY...MOST PLACES WILL HAVE TIME AHEAD OF
THE RAIN TO REACH THE 90S AGAIN. SOME OF CENTRAL GEORGIA WILL REACH
HEAT INDICES OF 100-102 THIS AFTERNOON WHICH FALLS SHORT OF A HEAT
ADVISORY /105 DEGREES OR GREATER HEAT INDICES FOR TWO CONSECUTIVE
DAYS/...BUT IT WILL STILL BE HOT AND FOLKS SHOULD KEEP THIS IN MIND
WHEN WORKING OUTSIDE AS ITS EXPECTED TO BE THE HOTTEST DAY OF THE
SEASON SO FAR.
11
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
/ISSUED 405 AM EDT WED JUN 12 2013/
A COLD FRONT WILL BE CLOSE TO CENTRAL GA AND MOVING S STARTING
THURSDAY NIGHT WITH POTENTIAL FOR SEVERE STORMS ASSOCIATED. THE
FRONT EXITS THE FORECAST AREA LATER THURSDAY NIGHT WITH THE GFS THE
FASTEST...THE NAM NEXT AND THE EUROPEAN THE SLOWEST.
PRECIP CHANCES MOST LIKELY WILL HAVE ENDED FOR FRIDAY ALTHOUGH THE
EUROPEAN HOLDS ONTO CHANCES OVER CENTRAL GA. SATURDAY IS DRY AS HIGH
PRESSURE ALOFT OVER THE LOWER MS VALLEY HELPS FOR HOLD ANY
CONVECTION AT BAY...HOWEVER NW FLOW ALOFT IS OVER THE AREA BUT
APPEARS TO HAVE ONLY MINIMAL MOISTURE. SUNDAY APPEARS ONE OF THOSE
DAYS WHERE YOU COULD GO EITHER WAY WITH 20 PERCENT POPS OVER THE NW
HALF OR SO OF THE AREA AS THE UPPER RIDGE FLATTENS AND SOME
INSTABILITY DEVELOPS WITH MINIMAL MOISTURE. FOR NOW WILL JUST HOLD
ONTO 10 PERCENT ACROSS THE NW. THE SOUTHERN EDGE OF THE WESTERLIES
RETURN FOR MONDAY AND TUESDAY WITH INCREASED MOISTURE AND INSTABILITY
ACROSS THE AREA AND THE POSSIBILITY FOR SHORT WAVES TO ENHANCE THE
POTENTIAL FOR SCATTERED SHOWERS AND THUNDERSTORMS. A WEAK COLD FRONT
MAY GET INTO N GA FOR WEDNESDAY.
BDL
&&
.AVIATION...
12Z UPDATE...
EXCEPT FOR SOME MVFR VSBYS THIS MORNING DUE TO FOG...VFR
CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. BIGGEST
UNCERTAINTY IS IN REGARDS TO THE PRECIPITATION FORECAST FOR TODAY.
HAVE A DISTURBANCE ROUNDING THE EDGE OF THE UPPER RIDGE AND MODELS
DIFFER ON IF CONVECTION WILL MOVE INTO GEORGIA. FOR NOW...THINKING
IS ANY CONVECTION THAT DEVELOPS WILL REMAIN NORTH AND EAST OF THE
TERMINALS. OF ALL THE SITES THOUGH...AHN AGAIN WOULD BE MOST
LIKELY TO SEE AN ISOLD THUNDERSTORM. OVERALL SHOULD SEE NW
WINDS...HOWEVER ONE MODEL IS PICKING UP AT A BRIEF PERIOD OF NE
AND THUS THE REASON FOR MEDIUM CONFIDENCE ON WINDS.
//ATL CONFIDENCE...12Z UPDATE...
HIGH CONFIDENCE ON CIGS AND VSBYS. MEDIUM CONFIDENCE ON WINDS.
MEDIUM CONFIDENCE ON ISOLD CONVECTION STAYING OUT OF THE
TERMINAL.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 95 70 94 67 / 20 10 50 20
ATLANTA 92 74 92 68 / 10 10 50 30
BLAIRSVILLE 88 67 86 59 / 20 20 50 20
CARTERSVILLE 93 70 93 65 / 10 10 50 20
COLUMBUS 95 75 96 73 / 10 10 20 40
GAINESVILLE 91 72 91 66 / 20 20 50 20
MACON 95 71 96 69 / 10 10 20 40
ROME 94 70 92 66 / 20 10 50 10
PEACHTREE CITY 92 69 93 67 / 10 10 50 30
VIDALIA 96 75 97 73 / 10 5 20 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11
LONG TERM....BDL
AVIATION...11
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
405 AM EDT WED JUN 12 2013
.SHORT TERM /TODAY THROUGH THURSDAY/...
ANOTHER HOT DAY ACROSS THE CWA AS THE AREA REMAINS UNDER THE EASTERN
EDGE OF AN UPPER LEVEL RIDGE. SOME DECENT UNCERTAINTY IN THE POP
FORECAST FOR TODAY. GFS SHOWS A STRONG VORT MAX ROUNDING THE UPPER
LEVEL RIDGE AND BRINGS IT INTO NORTH GEORGIA BY MID MORNING. GFS
ISNT GENERATING MUCH IN TERMS OF PRECIP WITH IT THOUGH ACROSS THE
CWA. NAM SHOWS SOME REFLECTION OF A SHORTWAVE BUT IS WEAKER AND
GENERALLY FURTHER EAST. EVEN HARDER TO PICK OUT THE FEATURE IN THE
ECMWF. DESPITE THIS THOUGH...ECMWF AND NAM ARE THE HIGHEST IN TERMS
OF PRECIP CHANCES ACROSS NORTH GEORGIA TODAY. HRRR IS PICKING UP ON
SOME ACTIVITY IN NORTH GEORGIA ASSOCIATED WITH THIS. FOR THE
FORECAST TRIED TO MEET IN THE MIDDLE AND HAVE SHOWN SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS THE NORTH. LEE SIDE TROUGH APPEARS
IT SHOULD BE JUST SOUTH OF THE CWA THIS AFTERNOON AND IF SOMETHING
WERE TO DEVELOP...THINK IT SHOULD BE ALONG THIS BOUNDARY...SO KEPT
MENTION OF POPS OUT OF CENTRAL GEORGIA.
THURSDAY IS THE BETTER CHANCE OF RAIN IN THE SHORT TERM AS A STRONG
SHORTWAVE MOVES FROM THE OHIO VALLEY INTO THE MID ATLANTIC AND A
COLD FRONT MOVES INTO GEORGIA. MODELS ARE IN GOOD AGREEMENT WITH THE
COLD FRONT MOVING INTO THE NORTH THURSDAY MORNING AND INTO CENTRAL
GEORGIA BY THE EVENING. DECENT INSTABILITY WITH THE SYSTEM WITH THE
GFS SHOWING ML CAPE AROUND 2000 J/KG. LL SHEAR IS NON-ZERO WITH
AROUND 20KTS ACROSS CENTRAL GEORGIA. WITH THE INSTABILITY...A
BOUNDARY TO FOCUS ON AND UPPER LEVEL SUPPORT...ISOLD SEVERE STORMS
ARE POSSIBLE ON THURSDAY WITH THE MAIN THREATS BEING WIND AND HAIL.
TOTAL RAINFALL AMOUNTS SHOULD BE MINIMAL...AROUND A QUARTER INCH OR
LESS WITH LOCALLY HIGHER AMOUNTS IN SOME OF THE THUNDERSTORMS.
BOTH AHN AND ATL SAW THEIR FIRST 90 DEGREE DAY FOR THE YEAR
YESTERDAY AND ALL OF NORTH AND CENTRAL GEORGIA IS EXPECTED TO REACH
THE LOW TO MID 90S AGAIN TODAY EXCEPT FOR THE MOUNTAINS. EVEN WITH
THE FRONT EXPECTED ON THURSDAY...MOST PLACES WILL HAVE TIME AHEAD OF
THE RAIN TO REACH THE 90S AGAIN. SOME OF CENTRAL GEORGIA WILL REACH
HEAT INDICES OF 100-102 THIS AFTERNOON WHICH FALLS SHORT OF A HEAT
ADVISORY /105 DEGREES OR GREATER HEAT INDICES FOR TWO CONSECUTIVE
DAYS/...BUT IT WILL STILL BE HOT AND FOLKS SHOULD KEEP THIS IN MIND
WHEN WORKING OUTSIDE AS ITS EXPECTED TO BE THE HOTTEST DAY OF THE
SEASON SO FAR.
11
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A COLD FRONT WILL BE CLOSE TO CENTRAL GA AND MOVING S STARTING
THURSDAY NIGHT WITH POTENTIAL FOR SEVERE STORMS ASSOCIATED. THE
FRONT EXITS THE FORECAST AREA LATER THURSDAY NIGHT WITH THE GFS THE
FASTEST...THE NAM NEXT AND THE EUROPEAN THE SLOWEST.
PRECIP CHANCES MOST LIKELY WILL HAVE ENDED FOR FRIDAY ALTHOUGH THE
EUROPEAN HOLDS ONTO CHANCES OVER CENTRAL GA. SATURDAY IS DRY AS HIGH
PRESSURE ALOFT OVER THE LOWER MS VALLEY HELPS FOR HOLD ANY
CONVECTION AT BAY...HOWEVER NW FLOW ALOFT IS OVER THE AREA BUT
APPEARS TO HAVE ONLY MINIMAL MOISTURE. SUNDAY APPEARS ONE OF THOSE
DAYS WHERE YOU COULD GO EITHER WAY WITH 20 PERCENT POPS OVER THE NW
HALF OR SO OF THE AREA AS THE UPPER RIDGE FLATTENS AND SOME
INSTABILITY DEVELOPS WITH MINIMAL MOISTURE. FOR NOW WILL JUST HOLD
ONTO 10 PERCENT ACROSS THE NW. THE SOUTHERN EDGE OF THE WESTERLIES
RETURN FOR MONDAY AND TUESDAY WITH INCREASED MOISTURE AND INSTABILITY
ACROSS THE AREA AND THE POSSIBILITY FOR SHORT WAVES TO ENHANCE THE
POTENTIAL FOR SCATTERED SHOWERS AND THUNDERSTORMS. A WEAK COLD FRONT
MAY GET INTO N GA FOR WEDNESDAY.
BDL
&&
.AVIATION...
06Z UPDATE...
MOSTLY HIGH CLOUDS ACROSS THE AREA TONIGHT AND WILL SEE SOME CU
DEVELOP THIS AFTERNOON. FOG EXPECTED TO DEVELOP THIS MORNING
BRINGING SOME VSBYS DOWN TO MVFR BUT WILL ONLY BE A FEW HOURS IN
DURATION. WITH A SHORTWAVE MOVING INTO NORTHEAST GEORGIA
TODAY...COULD SEE ISOLD TSRA DEVELOPMENT...BUT EXPECT IT TO REMAIN
NORTH OF THE TAF SITES. IF SOMETHING WERE TO DEVELOP AND PUSH
SOUTHEAST...AHN HAS THE BEST CHANCE OF SEEING A THUNDERSTORM OF
ALL THE TAF SITES.
//ATL CONFIDENCE...06Z UPDATE...
HIGH CONFIDENCE ON ALL ELEMENTS.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 95 70 94 67 / 20 10 50 20
ATLANTA 92 74 92 68 / 10 10 50 30
BLAIRSVILLE 88 67 86 59 / 20 20 50 20
CARTERSVILLE 93 70 93 65 / 10 10 50 20
COLUMBUS 95 75 96 73 / 10 10 20 40
GAINESVILLE 91 72 91 66 / 20 20 50 20
MACON 95 71 96 69 / 10 10 20 40
ROME 94 70 92 66 / 20 10 50 10
PEACHTREE CITY 92 69 93 67 / 10 10 50 30
VIDALIA 96 75 97 73 / 10 5 20 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11
LONG TERM....BDL
AVIATION...11
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
522 PM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
510 PM CDT
AS STORMS MOVE INTO NORTHEAST ILLINOIS AND THE FAR WESTERN
SUBURBS OF METRO CHICAGO A LAKE BREEZE BOUNDARY...AND POSSIBLY
ALSO THE STATIONARY FRONT...APPEARS TO EXTEND EAST FROM THE
PRIMARY CLUSTER OF STORMS THROUGH NORTHWEST WILL COUNTY INTO
CENTRAL LAKE COUNTY INDIANA. THIS APPEARS TO BE THE BOUNDARY WHERE
ROTATION HAS BEEN FOCUSING PERIODICALLY IN SOUTHERN DE KALB
COUNTY. CAPE VALUES FALL SOMEWHAT ALONG THE LAKEFRONT...BUT THERE
APPEARS TO BE PLENTY OF SUPPORT FOR SUSTAINING THE EXISTING
ACTIVITY INTO AND SOUTH OF THE CHICAGO METRO AREA...AND EVEN INTO
DOWNTOWN ITSELF. TORNADO SPINUPS ARE VERY POSSIBLE WITH THIS
CLUSTER OF STORMS...ESPECIALLY ALONG THE BOUNDARY IN NORTHERN
KENDALL INTO NORTHWEST WILL COUNTY...AND DAMAGING WINDS AND HAIL
REMAIN EQUALLY LIKELY.
LENNING
243 PM CDT
COUPLE QUICK THOUGHTS ON SOME EVOLUTIONS IN THE MESOSCALE
ENVIRONMENT IN THE PAST 60 TO 90 MINS. DEEPER MIXING IN THE WARM
SECTOR IS ALLOWING SFC WINDS TO VEER CONSIDERABLY ACROSS THE WARM
SECTOR...WHICH IS SIGNIFICANTLY LOWERING THE LOW LEVEL SHEAR AND
POTENTIAL FOR LONG TRACK OR SIGNIFICANT TORNADOES IN THE WARM
SECTOR. WILL NEED TO MONITOR FOR ANY BACKING OF LOW LEVEL FLOW IN
THE WARM SECTOR THIS EVENING...BUT AT THIS POINT IN OUR CWA THE
MORE SIGNIFICANT TORNADO AND HIGH END WIND DAMAGE THREAT WOULD
LIKELY END UP NEAR THE SFC BOUNDARY STALLED OUT FROM ROUGHLY NEAR
CHICAGO WNW TO DBQ. THIS BOUNDARY MAY YET FLUCTUATE SOME THIS
AFTERNOON...BUT WHERE EVER THIS BOUNDARY ENDS UP IS WHERE THE
HIGHEST END SEVERE THREAT WILL LIKELY EXIST WITH SUPERCELL OR MORE
LIKELY WITH STRONG MV`S ALONG LEADING EDGE OF BOW THIS EVENING.
THE 1800 UTC SOUNDINGS FROM DVN AND ILX STILL SHOW A STRONG CAP
PRESENT...HOWEVER COMPARISON OF BOTH SOUNDINGS SHOW EVIDENCE OF
ASCENT TAKING PLACE AND BEGINNING TO LIFT THROUGH THE CAP. ALSO
SEEING EVIDENCE OF THIS ON VISIBLE SATELLITE IMAGERY WITH
GRADUALLY DEEPENING CU FIELD OVER NW IL. HAVE BEGUN TO SEE
CONVECTIVE INITIATION OVER NE IA ALREADY AND EXPECT MORE EXPLOSIVE
SEVERE THUNDERSTORM DEVELOPMENT TO TAKE PLACE WITHIN THE NEXT HOUR
OR TWO.
IZZI
130 PM CDT
THE MAIN THOUGHTS ON THE THREATS AND TIMING ON THE LIKELY SEVERE
WEATHER OUTBREAK REMAIN SIMILAR.
VISIBLE SATELLITE INDICATES MORE AGITATION IN THE ACCAS IN WEST-
TO-EAST BANDS ACROSS THE AREA WITH LIGHT ECHOES CONTINUING ON THE
RADAR MOSAIC. THESE ARE SIGNS OF THE ELEVATED WARM AIR ADVECTION
AND ACTUALLY ALREADY SOME MAMMATUS HAVE BEEN SEEN. STEEP LAPSE
RATES SEEN ON AMDAR DATA AND THE 18Z DVN RAOB ABOVE THIS LAYER
COULD SUPPORT SCATTERED CONVECTION DEVELOPING ACROSS NORTHERN IL
AND FAR NORTHWEST IN WITHIN THE NEXT TWO TO THREE HOURS.
OF GREATER CONCERN IS CONVECTIVE DEVELOPMENT LIKELY OVER NORTHEAST
IA/SOUTHWEST WI/NORTHWEST IL. THE PRIMARY 1004MB SURFACE LOW
ACROSS CENTRAL IA CONTINUES TO DEVELOP EAST WITH 5 MB/3 HR
PRESSURE FALLS CENTERED OVER THE CWA WHERE THE WARM FRONTAL
BOUNDARY HAS POSITIONED ITSELF. THIS BOUNDARY HAS UNDULATED
SOME...BUT APPEARS TO BE NORTH OF I-88 ESE INTO THE CHICAGO METRO
AREA...AND WILL POTENTIALLY BECOME MORE DEFINED WITH CLEARING
OCCURRING ACROSS THE SOUTHERN FORECAST AREA. PRONOUNCED DRYING ON
WATER VAPOR AHEAD OF THE MAIN SHORT WAVE IN SOUTHERN MN AND A MID-
LEVEL WIND MAX WILL CONTINUE TO MOVE EAST AND OVERRIDE THE WARM
FRONTAL REGION ACROSS EASTERN IA SHORTLY. THE DEVELOPMENT OF
CONVECTION SEEN ON HIGH RESOLUTION GUIDANCE ALONG AND NORTH OF THE
WARM FRONT IN THIS AREA IS SUPPORTED BY OBSERVATIONAL
TRENDS...WITH THE DVN RAOB AND RAP ANALYSIS HAVING INDICATED THE
CAP TO BE ERODED.
THIS LIKELY DISCRETE DEVELOPMENT AT FIRST WILL AGAIN EVOLVE EAST
ACROSS NORTH CENTRAL IL AFTER MAINLY 4 PM. THE INSTABILITY AND
SHEAR SPECTRUM OF THE CURRENT ATMOSPHERE ARE NO PROBLEMS FOR
SEVERE STORMS...WITH HIGH CAPE GREATER THAN 2500 J/KG AND
EFFECTIVE DEEP LAYER SHEAR IN EXCESS OF 45 KTS. SUPERCELLS WILL
CERTAINLY BE SUPPORTED. SOME DEVELOPMENT EAST OF THE INITIAL
CELLS...POSSIBLY SURFACE BASED...MAY OCCUR TOO DEPENDING ON IF THE
CIN CAN ERODE AND THE CONVERGENCE ALONG THE SURFACE BOUNDARY IS
ENHANCED. THIS LENDS TO UNCERTAINTY ON WHEN THE FIRST ROBUST
ACTIVITY COULD REACH CHICAGO. BUT THE PRIMARY THREAT TIMES STILL
LOOK TO BE 4-7 PM IN AND AROUND ROCKFORD AND 6-11 PM IN CHICAGO.
OBSERVATIONAL TRENDS CONTINUE TO POINT TOWARDS THE POTENTIAL FOR A
ROBUST MCS...WITH WINDS POTENTIALLY 80 TO 100 MPH WINDS...DEVELOPING
ACROSS THE AREA THIS EVE. ALL INGREDIENTS ARE FAVORABLE FOR
THIS...INCLUDING A STRONG MID-LEVEL JET...SUFFICIENT 0-3 KM SHEAR
FOR COLD POOL ORGANIZATION...A LARGE AREA OF HIGH DOWNDRAFT
CAPE...AND A VEERING STRONG LOW-LEVEL JET INTO A EXISTING
BAROCLINIC GRADIENT. MANY OF THE CONVECTIVE ALLOWING GUIDANCE
INDICATE NOT ONLY MCV TYPE STRUCTURE ACROSS FAR NORTHERN IL RACING
INTO CHICAGO AND NORTHWEST IN THIS EVE...BUT ALSO AGREE ON HIGH
SURFACE-BASED WINDS. RAP AND NAM FORECASTS INTO TONIGHT FOR THE
ENVIRONMENT WOULD SUPPORT THIS AS WOULD THE CONCEPTUAL MODEL OF A
QUICKLY EASTWARD DEVELOPING SURFACE LOW. SOMETHING TO KEEP IN MIND
WITH THE POSSIBLE PATH OF THIS ACROSS FAR SOUTHERN LAKE MI IS THAT
A SEICHE WOULD BE FAVORED IF THAT WERE TO OCCUR. THE 12Z LOCAL ARW
ACTUALLY APPEARS TO HAVE THAT FORECAST IN THE PRESSURE FIELDS.
WILL MENTION THIS AND THE HIGHER ENDS WINDS OVER LAND IN THE HWO.+
&&
.DISCUSSION...
310 PM CDT
FOR WEDNESDAY NIGHT THROUGH TUESDAY...
FOR THE OVERNIGHT HOURS...THE CONCERNS WILL STILL FOCUS ON THE
POTENTIAL FOR SEVERE WEATHER AS WELL AS THE CHANCES FOR FLOODING AND
FLASH FLOODING. FOR DETAILS ON THE FLOODING POTENTIAL...SEE THE
HYDROLOGY DISCUSSION BELOW. THAT SAID...THE ENVIRONMENT WILL BE
PRIMED FOR ANY THUNDERSTORMS TO BE EFFICIENT RAIN PRODUCERS AS THEY
WILL BE IN A VERY MOIST ENVIRONMENT WITH SFC DEWPOINTS IN THE LOW
70S AND PWATS BETWEEN 1.75 AND 2.00 INCHES. FROM A CLIMATOLOGICAL
PERSPECTIVE...THIS PUTS THE REGION IN THE MAXIMUM POTENTIAL FOR THE
MIDDLE OF JUNE. WIDESPREAD AMOUNTS OF 2 TO 3 INCHES ARE
LIKELY...GENERALLY NORTH OF I-80...WITH LOCALIZED AMOUNTS OF UP TO 5
INCHES POSSIBLE IN AREAS WHERE REPEATED TRAINING OF HEAVY
THUNDERSTORMS MAY OCCUR. AT THIS POINT...EXPECT ACTIVE
THUNDERSTORMS OVER AT LEAST PORTIONS OF THE AREA THROUGH MUCH OF THE
NIGHT,,,WITH THUNDERSTORM POTENTIAL ENDING FROM WEST TO EAST DURG
THE EARLY MORNING HOURS.
AS THE SFC LOW ASSOCIATED WITH THE SEVERE WEATHER MOVES OFF TO THE
EAST TOMORROW...HIGH PRESSURE RIDGING...BOTH AT THE SFC AND
ALOFT...WILL BUILD ACROSS THE MIDDLE/UPPER MISSISSIPPI VALLEY AND
MIDWEST REGIONS. CONDITIONS WILL QUICKLY DRY OUT...WITH MOSTLY
CLEAR AND DRY CONDITIONS EXPECTED FOR THURSDAY AND FRIDAY.
TEMPERATURES WILL GENERALLY BE NEAR CLIMATOLOGICAL NORMALS WITH
HIGHS INN THE MIDDLE TO UPPER 70S. THE EXCEPTION WILL BE THE
IMMEDIATE LAKE FRONT WHERE A WEAK PRESSURE GRADIENT AND LIGHT WINDS
WILL ALLOW FOR DAILY LAKE BREEZE DEVELOPMENT. SO...EXPECT THAT THE
LAKE FRONT LOCATIONS SHOULD BE SIGNIFICANTLY COOLER THAT THE INLAND
AREAS WITH HIGHS ONLY IN THE LOWER TO MIDDLE 60S. SFC DEWPOINTS
WILL DROP OFF SIGNIFICANTLY AS WELL...DROPPING INTO THE UPPER 40S TO
LOWER 50S.
FOR THE WEEKEND...A SERIES OF SHORT WAVES WILL BEGIN TO OVERTOP THE
UPPER RIDGE AXIS...AND CROSS THE AREA THROUGH THE DEVELOPING
NORTHWEST FLOW ALOFT. THE FIRST OF THESE SHORT WAVES WILL APPROACH
THE REGION BY SATURDAY MORNING...BRINGING ANOTHER CHANCE FOR SHOWERS
AND THUNDERSTORMS. THE LATEST SPC DAY 3 CONVECTIVE OUTLOOK...12Z
FRIDAY THROUGH 12Z SATURDAY... INDICATES A SLIGHT RISK OF SEVERE
WEATHER OVER THE UPPER MISSOURI VALLEY ASSOCIATED WITH THIS SYSTEM.
THE LATEST DAY 4-8 CONVECTIVE OUTLOOK DOES NOT INDICATE SEVERE
POTENTIAL AT THIS POINT...BUT THE GUIDANCE DOES INDICATE THAT IT IS
A RATHER VIGOROUS WAVE...SO STRONG STORMS ARE A POSSIBILITY. THE
ONE LIMITING FACTOR COULD BE THE LOW LEVEL MOISTURE AVAILABILITY.
THE EXPECTED SFC DEW POINT TRENDS POINT TO A SLOW RETURN OF HIGHER
DEWPOINT AIR...WITH SFC DEWPOINTS ONLY IN THE LOWER TO MIDDLE 50S
FOR EARLY SATURDAY MORNING. DEWPOINTS SHOULD RETURN TO THE MIDDLE
TO UPPER 60S BY SATURDAY EVENING...BUT THE SHORTWAVE SHOULD HAVE
MOVED WELL TO THE EAST AND SHORT WAVE RIDGING WILL BUILD OVER THE
AREA. THIS COULD BRING A SHORT WEAKENING TREND IN THE THUNDERSTORM
POTENTIAL...BUT ANOTHER STRONG SHORT WAVE HOT ON IT`S HEALS WILL
RENEW THE THUNDERSTORM POTENTIAL FOR SATURDAY NIGHT AND LINGERING
INTO SUNDAY. WEAK HIGH PRESSURE AT THE SFC WILL HELP LOWER THE PCPN
POTENTIAL...BUT SOME ISOLATED ACTIVITY CANNOT BE RULES OUT THROUGH
SUNDAY AS TEMPERATURES RISE INTO THE LOWER 80S WITH SFC DEWPOINTS
EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.
FOR EARLY NEXT WEEK...THE TREND SHOULD BE FOR DECREASING CHANCES FOR
PCPN AND LOWERING TEMPERATURES. MONDAY IS EXPECTED TO REMAIN WARM
AND HUMID WITH HIGHS IN THE LOWER 80S AND DEWPOINTS IN THE MIDDLE TO
UPPER 60S. BY TUESDAY...COOLER/DRIER AIR SHOULD FILTER OVER THE
REGION AS HIGH PRESSURE SPREADS OUT OF THE NORTHERN PLAINS AND INTO
THE MIDWEST AND GREAT LAKES REGIONS.
KREIN
&&
.HYDROLOGY...
315 PM
HAVE CONTINUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
SUBLETTE ILLINOIS TO DUNNS BRIDGE INDIANA LINE...EXPANDING THE
WATCH AREA TO INCLUDE LEE COUNTY. THERE IS STILL THE POTENTIAL
FOR WIDESPREAD HEAVY RAINFALL OF 2 TO 3 INCHES ACROSS THIS
AREA...WITH LOCALLY UP TO 5 INCHES. THE AREA WILL BE UNDER PWATS
OF 1.75 TO 2 INCHES...WHICH PUTS THE AREA WITHING THE 100TH
PERCENTILE FOR PWATS FOR THE MIDDLE OF JUNE...WHICH ESSENTIALLY
SAYS THAT THE DEEP LAYER MOISTURE DOES NOT GET MUCH HIGHER THAN
THIS. THIS WOULD ALSO INDICATE THAT THE STORMS WILL BE VERY
EFFICIENT RAINFALL PRODUCERS WITH VERY HIGH RAINFALL RATES. WITH
THE AXIS OF HEAVIEST RAIN EXPECTED TO BE OVER LOCATIONS INCLUDING
THE HIGHLY URBANIZED ROCKFORD AND CHICAGO METRO AREAS...URBAN
FLOODING IN LOW LYING AREAS AND VIADUCTS LIKELY. THERE WILL ALSO
LIKELY BE FLOODING OF SMALL STREAMS AND SOME AREA RIVERS THAT HAVE
A REDUCED CAPACITY DUE TO PREVIOUS RAINFALL.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* STRONG/SEVERE THUNDERSTORM POTENTIAL LATE THIS AFTERNOON INTO
THIS EVENING THAT WILL HAVE SIGNIFICANT IMPACTS ON THE
TERMINALS.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR/LIFR VIS
AND IFR CIGS POSSIBLE FOR A PERIOD.
* EAST NORTHEAST WINDS...THEN INCREASING LATER THIS EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
CONTINUE TO MONITOR THE POTENTIAL FOR SIGNIFICANT WEATHER TO AFFECT
THE TERMINALS LATER THIS AFTERNOON THROUGH THIS EVENING. ALTHOUGH
AT THIS TIME...RATHER QUIET ACROSS THE TERMINALS WITH VFR
CONDITIONS IN PLACE. WITH THE TRACK OF THE LOW THIS
MORNING...WINDS HAVE ACTUALLY BEEN ORIENTED MORE OUT OF A
SOUTHERLY DIRECTION TODAY. THIS WILL CONTINUE TO OCCUR WITH SOME
SPORADIC GUSTS BUT WITH A SHIFT BACK TO THE EAST NORTHEAST BY MID
AFTERNOON...WITH WINDS REMAINING MORE NORTHERLY THROUGH THE END OF
THE FORECAST PERIOD. DO EXPECT AN INCREASE IN ACTIVITY BY MID
AFTERNOON WITH SCATTERED SHOWERS/THUNDERSTORMS EXPECTED TO DEVELOP
ACROSS THE TERMINALS. THIS INITIAL ONSET IS EXPECTED TO ONLY HAVE
LIMITED IMPACTS ON THE TERMINALS BUT WITH THIS TO QUICKLY CHANGE
AS WE GO INTO THE LATE AFTERNOON. THUNDERSTORM DEVELOPMENT WILL
INCREASE WITH COVERAGE/INTENSITY OF THESE STORMS ALSO INCREASING
AS THEY SHIFT EAST ACROSS THE TERMINALS. NOT ONLY WILL LOWER
VIS/CEILINGS IN HEAVY RAIN WILL BE POSSIBLE...BUT STRONG/SHIFTING
WINDS ARE DEFINITELY POSSIBLE WITH THE STRONGEST THUNDERSTORMS
LATER THIS AFTERNOON. THIS WILL HAVE TO BE ADDRESSED WITH LATER
AMENDMENTS ONCE THUNDERSTORM INITIATION OCCURS AND THE FULL
THREAT OF CHANGING WEATHER FOR THE TERMINALS IS KNOWN.
SHOWERS/ISOLATED THUNDER SHOULD DIMINISH LATE THIS EVENING THROUGH
OVERNIGHT...WITH DRIER CONDITIONS EXPECTED EARLY THURSDAY MORNING
AS WELL AS CEILINGS IMPROVING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE WITH THUNDERSTORM TRENDS THIS AFTERNOON...LOW
MEDIUM CONFIDENCE THROUGH TONIGHT.
* MEDIUM TO HIGH CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL
WITH LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022 UNTIL 4 AM
THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002 UNTIL 4 AM THURSDAY.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 PM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
513 PM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
510 PM CDT
AS STORMS MOVE INTO NORTHEAST ILLINOIS AND THE FAR WESTERN
SUBURBS OF METRO CHICAGO A LAKE BREEZE BOUNDARY...AND POSSIBLY
ALSO THE STATIONARY FRONT...APPEARS TO EXTEND EAST FROM THE
PRIMARY CLUSTER OF STORMS THROUGH NORTHWEST WILL COUNTY INTO
CENTRAL LAKE COUNTY INDIANA. THIS APPEARS TO BE THE BOUNDARY WHERE
ROTATION HAS BEEN FOCUSING PERIODICALLY IN SOUTHERN DE KALB
COUNTY. CAPE VALUES FALL SOMEWHAT ALONG THE LAKEFRONT...BUT THERE
APPEARS TO BE PLENTY OF SUPPORT FOR SUSTAINING THE EXISTING
ACTIVITY INTO AND SOUTH OF THE CHICAGO METRO AREA...AND EVEN INTO
DOWNTOWN ITSELF. TORNADO SPINUPS ARE VERY POSSIBLE WITH THIS
CLUSTER OF STORMS...ESPECIALLY ALONG THE BOUNDARY IN NORTHERN
KENDALL INTO NORTHWEST WILL COUNTY...AND DAMAGING WINDS AND HAIL
REMAIN EQUALLY LIKELY.
LENNING
243 PM CDT
COUPLE QUICK THOUGHTS ON SOME EVOLUTIONS IN THE MESOSCALE
ENVIRONMENT IN THE PAST 60 TO 90 MINS. DEEPER MIXING IN THE WARM
SECTOR IS ALLOWING SFC WINDS TO VEER CONSIDERABLY ACROSS THE WARM
SECTOR...WHICH IS SIGNIFICANTLY LOWERING THE LOW LEVEL SHEAR AND
POTENTIAL FOR LONG TRACK OR SIGNIFICANT TORNADOES IN THE WARM
SECTOR. WILL NEED TO MONITOR FOR ANY BACKING OF LOW LEVEL FLOW IN
THE WARM SECTOR THIS EVENING...BUT AT THIS POINT IN OUR CWA THE
MORE SIGNIFICANT TORNADO AND HIGH END WIND DAMAGE THREAT WOULD
LIKELY END UP NEAR THE SFC BOUNDARY STALLED OUT FROM ROUGHLY NEAR
CHICAGO WNW TO DBQ. THIS BOUNDARY MAY YET FLUCTUATE SOME THIS
AFTERNOON...BUT WHERE EVER THIS BOUNDARY ENDS UP IS WHERE THE
HIGHEST END SEVERE THREAT WILL LIKELY EXIST WITH SUPERCELL OR MORE
LIKELY WITH STRONG MV`S ALONG LEADING EDGE OF BOW THIS EVENING.
THE 1800 UTC SOUNDINGS FROM DVN AND ILX STILL SHOW A STRONG CAP
PRESENT...HOWEVER COMPARISON OF BOTH SOUNDINGS SHOW EVIDENCE OF
ASCENT TAKING PLACE AND BEGINNING TO LIFT THROUGH THE CAP. ALSO
SEEING EVIDENCE OF THIS ON VISIBLE SATELLITE IMAGERY WITH
GRADUALLY DEEPENING CU FIELD OVER NW IL. HAVE BEGUN TO SEE
CONVECTIVE INITIATION OVER NE IA ALREADY AND EXPECT MORE EXPLOSIVE
SEVERE THUNDERSTORM DEVELOPMENT TO TAKE PLACE WITHIN THE NEXT HOUR
OR TWO.
IZZI
130 PM CDT
THE MAIN THOUGHTS ON THE THREATS AND TIMING ON THE LIKELY SEVERE
WEATHER OUTBREAK REMAIN SIMILAR.
VISIBLE SATELLITE INDICATES MORE AGITATION IN THE ACCAS IN WEST-
TO-EAST BANDS ACROSS THE AREA WITH LIGHT ECHOES CONTINUING ON THE
RADAR MOSAIC. THESE ARE SIGNS OF THE ELEVATED WARM AIR ADVECTION
AND ACTUALLY ALREADY SOME MAMMATUS HAVE BEEN SEEN. STEEP LAPSE
RATES SEEN ON AMDAR DATA AND THE 18Z DVN RAOB ABOVE THIS LAYER
COULD SUPPORT SCATTERED CONVECTION DEVELOPING ACROSS NORTHERN IL
AND FAR NORTHWEST IN WITHIN THE NEXT TWO TO THREE HOURS.
OF GREATER CONCERN IS CONVECTIVE DEVELOPMENT LIKELY OVER NORTHEAST
IA/SOUTHWEST WI/NORTHWEST IL. THE PRIMARY 1004MB SURFACE LOW
ACROSS CENTRAL IA CONTINUES TO DEVELOP EAST WITH 5 MB/3 HR
PRESSURE FALLS CENTERED OVER THE CWA WHERE THE WARM FRONTAL
BOUNDARY HAS POSITIONED ITSELF. THIS BOUNDARY HAS UNDULATED
SOME...BUT APPEARS TO BE NORTH OF I-88 ESE INTO THE CHICAGO METRO
AREA...AND WILL POTENTIALLY BECOME MORE DEFINED WITH CLEARING
OCCURRING ACROSS THE SOUTHERN FORECAST AREA. PRONOUNCED DRYING ON
WATER VAPOR AHEAD OF THE MAIN SHORT WAVE IN SOUTHERN MN AND A MID-
LEVEL WIND MAX WILL CONTINUE TO MOVE EAST AND OVERRIDE THE WARM
FRONTAL REGION ACROSS EASTERN IA SHORTLY. THE DEVELOPMENT OF
CONVECTION SEEN ON HIGH RESOLUTION GUIDANCE ALONG AND NORTH OF THE
WARM FRONT IN THIS AREA IS SUPPORTED BY OBSERVATIONAL
TRENDS...WITH THE DVN RAOB AND RAP ANALYSIS HAVING INDICATED THE
CAP TO BE ERODED.
THIS LIKELY DISCRETE DEVELOPMENT AT FIRST WILL AGAIN EVOLVE EAST
ACROSS NORTH CENTRAL IL AFTER MAINLY 4 PM. THE INSTABILITY AND
SHEAR SPECTRUM OF THE CURRENT ATMOSPHERE ARE NO PROBLEMS FOR
SEVERE STORMS...WITH HIGH CAPE GREATER THAN 2500 J/KG AND
EFFECTIVE DEEP LAYER SHEAR IN EXCESS OF 45 KTS. SUPERCELLS WILL
CERTAINLY BE SUPPORTED. SOME DEVELOPMENT EAST OF THE INITIAL
CELLS...POSSIBLY SURFACE BASED...MAY OCCUR TOO DEPENDING ON IF THE
CIN CAN ERODE AND THE CONVERGENCE ALONG THE SURFACE BOUNDARY IS
ENHANCED. THIS LENDS TO UNCERTAINTY ON WHEN THE FIRST ROBUST
ACTIVITY COULD REACH CHICAGO. BUT THE PRIMARY THREAT TIMES STILL
LOOK TO BE 4-7 PM IN AND AROUND ROCKFORD AND 6-11 PM IN CHICAGO.
OBSERVATIONAL TRENDS CONTINUE TO POINT TOWARDS THE POTENTIAL FOR A
ROBUST MCS...WITH WINDS POTENTIALLY 80 TO 100 MPH WINDS...DEVELOPING
ACROSS THE AREA THIS EVE. ALL INGREDIENTS ARE FAVORABLE FOR
THIS...INCLUDING A STRONG MID-LEVEL JET...SUFFICIENT 0-3 KM SHEAR
FOR COLD POOL ORGANIZATION...A LARGE AREA OF HIGH DOWNDRAFT
CAPE...AND A VEERING STRONG LOW-LEVEL JET INTO A EXISTING
BAROCLINIC GRADIENT. MANY OF THE CONVECTIVE ALLOWING GUIDANCE
INDICATE NOT ONLY MCV TYPE STRUCTURE ACROSS FAR NORTHERN IL RACING
INTO CHICAGO AND NORTHWEST IN THIS EVE...BUT ALSO AGREE ON HIGH
SURFACE-BASED WINDS. RAP AND NAM FORECASTS INTO TONIGHT FOR THE
ENVIRONMENT WOULD SUPPORT THIS AS WOULD THE CONCEPTUAL MODEL OF A
QUICKLY EASTWARD DEVELOPING SURFACE LOW. SOMETHING TO KEEP IN MIND
WITH THE POSSIBLE PATH OF THIS ACROSS FAR SOUTHERN LAKE MI IS THAT
A SEICHE WOULD BE FAVORED IF THAT WERE TO OCCUR. THE 12Z LOCAL ARW
ACTUALLY APPEARS TO HAVE THAT FORECAST IN THE PRESSURE FIELDS.
WILL MENTION THIS AND THE HIGHER ENDS WINDS OVER LAND IN THE HWO.+
&&
.DISCUSSION...
310 PM CDT
FOR WEDNESDAY NIGHT THROUGH TUESDAY...
FOR THE OVERNIGHT HOURS...THE CONCERNS WILL STILL FOCUS ON THE
POTENTIAL FOR SEVERE WEATHER AS WELL AS THE CHANCES FOR FLOODING AND
FLASH FLOODING. FOR DETAILS ON THE FLOODING POTENTIAL...SEE THE
HYDROLOGY DISCUSSION BELOW. THAT SAID...THE ENVIRONMENT WILL BE
PRIMED FOR ANY THUNDERSTORMS TO BE EFFICIENT RAIN PRODUCERS AS THEY
WILL BE IN A VERY MOIST ENVIRONMENT WITH SFC DEWPOINTS IN THE LOW
70S AND PWATS BETWEEN 1.75 AND 2.00 INCHES. FROM A CLIMATOLOGICAL
PERSPECTIVE...THIS PUTS THE REGION IN THE MAXIMUM POTENTIAL FOR THE
MIDDLE OF JUNE. WIDESPREAD AMOUNTS OF 2 TO 3 INCHES ARE
LIKELY...GENERALLY NORTH OF I-80...WITH LOCALIZED AMOUNTS OF UP TO 5
INCHES POSSIBLE IN AREAS WHERE REPEATED TRAINING OF HEAVY
THUNDERSTORMS MAY OCCUR. AT THIS POINT...EXPECT ACTIVE
THUNDERSTORMS OVER AT LEAST PORTIONS OF THE AREA THROUGH MUCH OF THE
NIGHT,,,WITH THUNDERSTORM POTENTIAL ENDING FROM WEST TO EAST DURG
THE EARLY MORNING HOURS.
AS THE SFC LOW ASSOCIATED WITH THE SEVERE WEATHER MOVES OFF TO THE
EAST TOMORROW...HIGH PRESSURE RIDGING...BOTH AT THE SFC AND
ALOFT...WILL BUILD ACROSS THE MIDDLE/UPPER MISSISSIPPI VALLEY AND
MIDWEST REGIONS. CONDITIONS WILL QUICKLY DRY OUT...WITH MOSTLY
CLEAR AND DRY CONDITIONS EXPECTED FOR THURSDAY AND FRIDAY.
TEMPERATURES WILL GENERALLY BE NEAR CLIMATOLOGICAL NORMALS WITH
HIGHS INN THE MIDDLE TO UPPER 70S. THE EXCEPTION WILL BE THE
IMMEDIATE LAKE FRONT WHERE A WEAK PRESSURE GRADIENT AND LIGHT WINDS
WILL ALLOW FOR DAILY LAKE BREEZE DEVELOPMENT. SO...EXPECT THAT THE
LAKE FRONT LOCATIONS SHOULD BE SIGNIFICANTLY COOLER THAT THE INLAND
AREAS WITH HIGHS ONLY IN THE LOWER TO MIDDLE 60S. SFC DEWPOINTS
WILL DROP OFF SIGNIFICANTLY AS WELL...DROPPING INTO THE UPPER 40S TO
LOWER 50S.
FOR THE WEEKEND...A SERIES OF SHORT WAVES WILL BEGIN TO OVERTOP THE
UPPER RIDGE AXIS...AND CROSS THE AREA THROUGH THE DEVELOPING
NORTHWEST FLOW ALOFT. THE FIRST OF THESE SHORT WAVES WILL APPROACH
THE REGION BY SATURDAY MORNING...BRINGING ANOTHER CHANCE FOR SHOWERS
AND THUNDERSTORMS. THE LATEST SPC DAY 3 CONVECTIVE OUTLOOK...12Z
FRIDAY THROUGH 12Z SATURDAY... INDICATES A SLIGHT RISK OF SEVERE
WEATHER OVER THE UPPER MISSOURI VALLEY ASSOCIATED WITH THIS SYSTEM.
THE LATEST DAY 4-8 CONVECTIVE OUTLOOK DOES NOT INDICATE SEVERE
POTENTIAL AT THIS POINT...BUT THE GUIDANCE DOES INDICATE THAT IT IS
A RATHER VIGOROUS WAVE...SO STRONG STORMS ARE A POSSIBILITY. THE
ONE LIMITING FACTOR COULD BE THE LOW LEVEL MOISTURE AVAILABILITY.
THE EXPECTED SFC DEW POINT TRENDS POINT TO A SLOW RETURN OF HIGHER
DEWPOINT AIR...WITH SFC DEWPOINTS ONLY IN THE LOWER TO MIDDLE 50S
FOR EARLY SATURDAY MORNING. DEWPOINTS SHOULD RETURN TO THE MIDDLE
TO UPPER 60S BY SATURDAY EVENING...BUT THE SHORTWAVE SHOULD HAVE
MOVED WELL TO THE EAST AND SHORT WAVE RIDGING WILL BUILD OVER THE
AREA. THIS COULD BRING A SHORT WEAKENING TREND IN THE THUNDERSTORM
POTENTIAL...BUT ANOTHER STRONG SHORT WAVE HOT ON IT`S HEALS WILL
RENEW THE THUNDERSTORM POTENTIAL FOR SATURDAY NIGHT AND LINGERING
INTO SUNDAY. WEAK HIGH PRESSURE AT THE SFC WILL HELP LOWER THE PCPN
POTENTIAL...BUT SOME ISOLATED ACTIVITY CANNOT BE RULES OUT THROUGH
SUNDAY AS TEMPERATURES RISE INTO THE LOWER 80S WITH SFC DEWPOINTS
EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.
FOR EARLY NEXT WEEK...THE TREND SHOULD BE FOR DECREASING CHANCES FOR
PCPN AND LOWERING TEMPERATURES. MONDAY IS EXPECTED TO REMAIN WARM
AND HUMID WITH HIGHS IN THE LOWER 80S AND DEWPOINTS IN THE MIDDLE TO
UPPER 60S. BY TUESDAY...COOLER/DRIER AIR SHOULD FILTER OVER THE
REGION AS HIGH PRESSURE SPREADS OUT OF THE NORTHERN PLAINS AND INTO
THE MIDWEST AND GREAT LAKES REGIONS.
KREIN
&&
.HYDROLOGY...
315 PM
HAVE CONTINUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
SUBLETTE ILLINOIS TO DUNNS BRIDGE INDIANA LINE...EXPANDING THE
WATCH AREA TO INCLUDE LEE COUNTY. THERE IS STILL THE POTENTIAL
FOR WIDESPREAD HEAVY RAINFALL OF 2 TO 3 INCHES ACROSS THIS
AREA...WITH LOCALLY UP TO 5 INCHES. THE AREA WILL BE UNDER PWATS
OF 1.75 TO 2 INCHES...WHICH PUTS THE AREA WITHING THE 100TH
PERCENTILE FOR PWATS FOR THE MIDDLE OF JUNE...WHICH ESSENTIALLY
SAYS THAT THE DEEP LAYER MOISTURE DOES NOT GET MUCH HIGHER THAN
THIS. THIS WOULD ALSO INDICATE THAT THE STORMS WILL BE VERY
EFFICIENT RAINFALL PRODUCERS WITH VERY HIGH RAINFALL RATES. WITH
THE AXIS OF HEAVIEST RAIN EXPECTED TO BE OVER LOCATIONS INCLUDING
THE HIGHLY URBANIZED ROCKFORD AND CHICAGO METRO AREAS...URBAN
FLOODING IN LOW LYING AREAS AND VIADUCTS LIKELY. THERE WILL ALSO
LIKELY BE FLOODING OF SMALL STREAMS AND SOME AREA RIVERS THAT HAVE
A REDUCED CAPACITY DUE TO PREVIOUS RAINFALL.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* STRONG/SEVERE THUNDERSTORM POTENTIAL LATE THIS AFTERNOON INTO
THIS EVENING THAT COULD HAVE SIGNIFICANT IMPACTS ON THE
TERMINALS...SHOWERS/THUNDERSTORMS INCREASING AFTER 21Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR/LIFR VIS
AND IFR CIGS POSSIBLE FOR A PERIOD.
* EAST NORTHEAST WINDS...THEN INCREASING LATER THIS EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
CONTINUE TO MONITOR THE POTENTIAL FOR SIGNIFICANT WEATHER TO AFFECT
THE TERMINALS LATER THIS AFTERNOON THROUGH THIS EVENING. ALTHOUGH
AT THIS TIME...RATHER QUIET ACROSS THE TERMINALS WITH VFR
CONDITIONS IN PLACE. WITH THE TRACK OF THE LOW THIS
MORNING...WINDS HAVE ACTUALLY BEEN ORIENTED MORE OUT OF A
SOUTHERLY DIRECTION TODAY. THIS WILL CONTINUE TO OCCUR WITH SOME
SPORADIC GUSTS BUT WITH A SHIFT BACK TO THE EAST NORTHEAST BY MID
AFTERNOON...WITH WINDS REMAINING MORE NORTHERLY THROUGH THE END OF
THE FORECAST PERIOD. DO EXPECT AN INCREASE IN ACTIVITY BY MID
AFTERNOON WITH SCATTERED SHOWERS/THUNDERSTORMS EXPECTED TO DEVELOP
ACROSS THE TERMINALS. THIS INITIAL ONSET IS EXPECTED TO ONLY HAVE
LIMITED IMPACTS ON THE TERMINALS BUT WITH THIS TO QUICKLY CHANGE
AS WE GO INTO THE LATE AFTERNOON. THUNDERSTORM DEVELOPMENT WILL
INCREASE WITH COVERAGE/INTENSITY OF THESE STORMS ALSO INCREASING
AS THEY SHIFT EAST ACROSS THE TERMINALS. NOT ONLY WILL LOWER
VIS/CEILINGS IN HEAVY RAIN WILL BE POSSIBLE...BUT STRONG/SHIFTING
WINDS ARE DEFINITELY POSSIBLE WITH THE STRONGEST THUNDERSTORMS
LATER THIS AFTERNOON. THIS WILL HAVE TO BE ADDRESSED WITH LATER
AMENDMENTS ONCE THUNDERSTORM INITIATION OCCURS AND THE FULL
THREAT OF CHANGING WEATHER FOR THE TERMINALS IS KNOWN.
SHOWERS/ISOLATED THUNDER SHOULD DIMINISH LATE THIS EVENING THROUGH
OVERNIGHT...WITH DRIER CONDITIONS EXPECTED EARLY THURSDAY MORNING
AS WELL AS CEILINGS IMPROVING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM TO HIGH CONFIDENCE WITH THUNDERSTORM TRENDS THIS
AFTERNOON THROUGH TONIGHT.
* MEDIUM TO HIGH CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL
WITH LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022 UNTIL 4 AM
THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002 UNTIL 4 AM THURSDAY.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 PM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
316 PM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
243 PM CDT
COUPLE QUICK THOUGHTS ON SOME EVOLUTIONS IN THE MESOSCALE
ENVIRONMENT IN THE PAST 60 TO 90 MINS. DEEPER MIXING IN THE WARM
SECTOR IS ALLOWING SFC WINDS TO VEER CONSIDERABLY ACROSS THE WARM
SECTOR...WHICH IS SIGNIFICANTLY LOWERING THE LOW LEVEL SHEAR AND
POTENTIAL FOR LONG TRACK OR SIGNIFICANT TORNADOES IN THE WARM
SECTOR. WILL NEED TO MONITOR FOR ANY BACKING OF LOW LEVEL FLOW IN
THE WARM SECTOR THIS EVENING...BUT AT THIS POINT IN OUR CWA THE
MORE SIGNIFICANT TORNADO AND HIGH END WIND DAMAGE THREAT WOULD
LIKELY END UP NEAR THE SFC BOUNDARY STALLED OUT FROM ROUGHLY NEAR
CHICAGO WNW TO DBQ. THIS BOUNDARY MAY YET FLUCTUATE SOME THIS
AFTERNOON...BUT WHERE EVER THIS BOUNDARY ENDS UP IS WHERE THE
HIGHEST END SEVERE THREAT WILL LIKELY EXIST WITH SUPERCELL OR MORE
LIKELY WITH STRONG MV`S ALONG LEADING EDGE OF BOW THIS EVENING.
THE 1800 UTC SOUNDINGS FROM DVN AND ILX STILL SHOW A STRONG CAP
PRESENT...HOWEVER COMPARISON OF BOTH SOUNDINGS SHOW EVIDENCE OF
ASCENT TAKING PLACE AND BEGINNING TO LIFT THROUGH THE CAP. ALSO
SEEING EVIDENCE OF THIS ON VISIBLE SATELLITE IMAGERY WITH
GRADUALLY DEEPENING CU FIELD OVER NW IL. HAVE BEGUN TO SEE
CONVECTIVE INITIATION OVER NE IA ALREADY AND EXPECT MORE EXPLOSIVE
SEVERE THUNDERSTORM DEVELOPMENT TO TAKE PLACE WITHIN THE NEXT HOUR
OR TWO.
IZZI
130 PM CDT
THE MAIN THOUGHTS ON THE THREATS AND TIMING ON THE LIKELY SEVERE
WEATHER OUTBREAK REMAIN SIMILAR.
VISIBLE SATELLITE INDICATES MORE AGITATION IN THE ACCAS IN WEST-
TO-EAST BANDS ACROSS THE AREA WITH LIGHT ECHOES CONTINUING ON THE
RADAR MOSAIC. THESE ARE SIGNS OF THE ELEVATED WARM AIR ADVECTION
AND ACTUALLY ALREADY SOME MAMMATUS HAVE BEEN SEEN. STEEP LAPSE
RATES SEEN ON AMDAR DATA AND THE 18Z DVN RAOB ABOVE THIS LAYER
COULD SUPPORT SCATTERED CONVECTION DEVELOPING ACROSS NORTHERN IL
AND FAR NORTHWEST IN WITHIN THE NEXT TWO TO THREE HOURS.
OF GREATER CONCERN IS CONVECTIVE DEVELOPMENT LIKELY OVER NORTHEAST
IA/SOUTHWEST WI/NORTHWEST IL. THE PRIMARY 1004MB SURFACE LOW
ACROSS CENTRAL IA CONTINUES TO DEVELOP EAST WITH 5 MB/3 HR
PRESSURE FALLS CENTERED OVER THE CWA WHERE THE WARM FRONTAL
BOUNDARY HAS POSITIONED ITSELF. THIS BOUNDARY HAS UNDULATED
SOME...BUT APPEARS TO BE NORTH OF I-88 ESE INTO THE CHICAGO METRO
AREA...AND WILL POTENTIALLY BECOME MORE DEFINED WITH CLEARING
OCCURRING ACROSS THE SOUTHERN FORECAST AREA. PRONOUNCED DRYING ON
WATER VAPOR AHEAD OF THE MAIN SHORT WAVE IN SOUTHERN MN AND A MID-
LEVEL WIND MAX WILL CONTINUE TO MOVE EAST AND OVERRIDE THE WARM
FRONTAL REGION ACROSS EASTERN IA SHORTLY. THE DEVELOPMENT OF
CONVECTION SEEN ON HIGH RESOLUTION GUIDANCE ALONG AND NORTH OF THE
WARM FRONT IN THIS AREA IS SUPPORTED BY OBSERVATIONAL
TRENDS...WITH THE DVN RAOB AND RAP ANALYSIS HAVING INDICATED THE
CAP TO BE ERODED.
THIS LIKELY DISCRETE DEVELOPMENT AT FIRST WILL AGAIN EVOLVE EAST
ACROSS NORTH CENTRAL IL AFTER MAINLY 4 PM. THE INSTABILITY AND
SHEAR SPECTRUM OF THE CURRENT ATMOSPHERE ARE NO PROBLEMS FOR
SEVERE STORMS...WITH HIGH CAPE GREATER THAN 2500 J/KG AND
EFFECTIVE DEEP LAYER SHEAR IN EXCESS OF 45 KTS. SUPERCELLS WILL
CERTAINLY BE SUPPORTED. SOME DEVELOPMENT EAST OF THE INITIAL
CELLS...POSSIBLY SURFACE BASED...MAY OCCUR TOO DEPENDING ON IF THE
CIN CAN ERODE AND THE CONVERGENCE ALONG THE SURFACE BOUNDARY IS
ENHANCED. THIS LENDS TO UNCERTAINTY ON WHEN THE FIRST ROBUST
ACTIVITY COULD REACH CHICAGO. BUT THE PRIMARY THREAT TIMES STILL
LOOK TO BE 4-7 PM IN AND AROUND ROCKFORD AND 6-11 PM IN CHICAGO.
OBSERVATIONAL TRENDS CONTINUE TO POINT TOWARDS THE POTENTIAL FOR A
ROBUST MCS...WITH WINDS POTENTIALLY 80 TO 100 MPH WINDS...DEVELOPING
ACROSS THE AREA THIS EVE. ALL INGREDIENTS ARE FAVORABLE FOR
THIS...INCLUDING A STRONG MID-LEVEL JET...SUFFICIENT 0-3 KM SHEAR
FOR COLD POOL ORGANIZATION...A LARGE AREA OF HIGH DOWNDRAFT
CAPE...AND A VEERING STRONG LOW-LEVEL JET INTO A EXISTING
BAROCLINIC GRADIENT. MANY OF THE CONVECTIVE ALLOWING GUIDANCE
INDICATE NOT ONLY MCV TYPE STRUCTURE ACROSS FAR NORTHERN IL RACING
INTO CHICAGO AND NORTHWEST IN THIS EVE...BUT ALSO AGREE ON HIGH
SURFACE-BASED WINDS. RAP AND NAM FORECASTS INTO TONIGHT FOR THE
ENVIRONMENT WOULD SUPPORT THIS AS WOULD THE CONCEPTUAL MODEL OF A
QUICKLY EASTWARD DEVELOPING SURFACE LOW. SOMETHING TO KEEP IN MIND
WITH THE POSSIBLE PATH OF THIS ACROSS FAR SOUTHERN LAKE MI IS THAT
A SEICHE WOULD BE FAVORED IF THAT WERE TO OCCUR. THE 12Z LOCAL ARW
ACTUALLY APPEARS TO HAVE THAT FORECAST IN THE PRESSURE FIELDS.
WILL MENTION THIS AND THE HIGHER ENDS WINDS OVER LAND IN THE HWO.+
&&
.DISCUSSION...
310 PM CDT
FOR WEDNESDAY NIGHT THROUGH TUESDAY...
FOR THE OVERNIGHT HOURS...THE CONCERNS WILL STILL FOCUS ON THE
POTENTIAL FOR SEVERE WEATHER AS WELL AS THE CHANCES FOR FLOODING AND
FLASH FLOODING. FOR DETAILS ON THE FLOODING POTENTIAL...SEE THE
HYDROLOGY DISCUSSION BELOW. THAT SAID...THE ENVIRONMENT WILL BE
PRIMED FOR ANY THUNDERSTORMS TO BE EFFICIENT RAIN PRODUCERS AS THEY
WILL BE IN A VERY MOIST ENVIRONMENT WITH SFC DEWPOINTS IN THE LOW
70S AND PWATS BETWEEN 1.75 AND 2.00 INCHES. FROM A CLIMATOLOGICAL
PERSPECTIVE...THIS PUTS THE REGION IN THE MAXIMUM POTENTIAL FOR THE
MIDDLE OF JUNE. WIDESPREAD AMOUNTS OF 2 TO 3 INCHES ARE
LIKELY...GENERALLY NORTH OF I-80...WITH LOCALIZED AMOUNTS OF UP TO 5
INCHES POSSIBLE IN AREAS WHERE REPEATED TRAINING OF HEAVY
THUNDERSTORMS MAY OCCUR. AT THIS POINT...EXPECT ACTIVE
THUNDERSTORMS OVER AT LEAST PORTIONS OF THE AREA THROUGH MUCH OF THE
NIGHT,,,WITH THUNDERSTORM POTENTIAL ENDING FROM WEST TO EAST DURG
THE EARLY MORNING HOURS.
AS THE SFC LOW ASSOCIATED WITH THE SEVERE WEATHER MOVES OFF TO THE
EAST TOMORROW...HIGH PRESSURE RIDGING...BOTH AT THE SFC AND
ALOFT...WILL BUILD ACROSS THE MIDDLE/UPPER MISSISSIPPI VALLEY AND
MIDWEST REGIONS. CONDITIONS WILL QUICKLY DRY OUT...WITH MOSTLY
CLEAR AND DRY CONDITIONS EXPECTED FOR THURSDAY AND FRIDAY.
TEMPERATURES WILL GENERALLY BE NEAR CLIMATOLOGICAL NORMALS WITH
HIGHS INN THE MIDDLE TO UPPER 70S. THE EXCEPTION WILL BE THE
IMMEDIATE LAKE FRONT WHERE A WEAK PRESSURE GRADIENT AND LIGHT WINDS
WILL ALLOW FOR DAILY LAKE BREEZE DEVELOPMENT. SO...EXPECT THAT THE
LAKE FRONT LOCATIONS SHOULD BE SIGNIFICANTLY COOLER THAT THE INLAND
AREAS WITH HIGHS ONLY IN THE LOWER TO MIDDLE 60S. SFC DEWPOINTS
WILL DROP OFF SIGNIFICANTLY AS WELL...DROPPING INTO THE UPPER 40S TO
LOWER 50S.
FOR THE WEEKEND...A SERIES OF SHORT WAVES WILL BEGIN TO OVERTOP THE
UPPER RIDGE AXIS...AND CROSS THE AREA THROUGH THE DEVELOPING
NORTHWEST FLOW ALOFT. THE FIRST OF THESE SHORT WAVES WILL APPROACH
THE REGION BY SATURDAY MORNING...BRINGING ANOTHER CHANCE FOR SHOWERS
AND THUNDERSTORMS. THE LATEST SPC DAY 3 CONVECTIVE OUTLOOK...12Z
FRIDAY THROUGH 12Z SATURDAY... INDICATES A SLIGHT RISK OF SEVERE
WEATHER OVER THE UPPER MISSOURI VALLEY ASSOCIATED WITH THIS SYSTEM.
THE LATEST DAY 4-8 CONVECTIVE OUTLOOK DOES NOT INDICATE SEVERE
POTENTIAL AT THIS POINT...BUT THE GUIDANCE DOES INDICATE THAT IT IS
A RATHER VIGOROUS WAVE...SO STRONG STORMS ARE A POSSIBILITY. THE
ONE LIMITING FACTOR COULD BE THE LOW LEVEL MOISTURE AVAILABILITY.
THE EXPECTED SFC DEW POINT TRENDS POINT TO A SLOW RETURN OF HIGHER
DEWPOINT AIR...WITH SFC DEWPOINTS ONLY IN THE LOWER TO MIDDLE 50S
FOR EARLY SATURDAY MORNING. DEWPOINTS SHOULD RETURN TO THE MIDDLE
TO UPPER 60S BY SATURDAY EVENING...BUT THE SHORTWAVE SHOULD HAVE
MOVED WELL TO THE EAST AND SHORT WAVE RIDGING WILL BUILD OVER THE
AREA. THIS COULD BRING A SHORT WEAKENING TREND IN THE THUNDERSTORM
POTENTIAL...BUT ANOTHER STRONG SHORT WAVE HOT ON IT`S HEALS WILL
RENEW THE THUNDERSTORM POTENTIAL FOR SATURDAY NIGHT AND LINGERING
INTO SUNDAY. WEAK HIGH PRESSURE AT THE SFC WILL HELP LOWER THE PCPN
POTENTIAL...BUT SOME ISOLATED ACTIVITY CANNOT BE RULES OUT THROUGH
SUNDAY AS TEMPERATURES RISE INTO THE LOWER 80S WITH SFC DEWPOINTS
EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.
FOR EARLY NEXT WEEK...THE TREND SHOULD BE FOR DECREASING CHANCES FOR
PCPN AND LOWERING TEMPERATURES. MONDAY IS EXPECTED TO REMAIN WARM
AND HUMID WITH HIGHS IN THE LOWER 80S AND DEWPOINTS IN THE MIDDLE TO
UPPER 60S. BY TUESDAY...COOLER/DRIER AIR SHOULD FILTER OVER THE
REGION AS HIGH PRESSURE SPREADS OUT OF THE NORTHERN PLAINS AND INTO
THE MIDWEST AND GREAT LAKES REGIONS.
KREIN
&&
.HYDROLOGY...
315 PM
HAVE CONTINUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
SUBLETTE ILLINOIS TO DUNNS BRIDGE INDIANA LINE...EXPANDING THE
WATCH AREA TO INCLUDE LEE COUNTY. THERE IS STILL THE POTENTIAL
FOR WIDESPREAD HEAVY RAINFALL OF 2 TO 3 INCHES ACROSS THIS
AREA...WITH LOCALLY UP TO 5 INCHES. THE AREA WILL BE UNDER PWATS
OF 1.75 TO 2 INCHES...WHICH PUTS THE AREA WITHING THE 100TH
PERCENTILE FOR PWATS FOR THE MIDDLE OF JUNE...WHICH ESSENTIALLY
SAYS THAT THE DEEP LAYER MOISTURE DOES NOT GET MUCH HIGHER THAN
THIS. THIS WOULD ALSO INDICATE THAT THE STORMS WILL BE VERY
EFFICIENT RAINFALL PRODUCERS WITH VERY HIGH RAINFALL RATES. WITH
THE AXIS OF HEAVIEST RAIN EXPECTED TO BE OVER LOCATIONS INCLUDING
THE HIGHLY URBANIZED ROCKFORD AND CHICAGO METRO AREAS...URBAN
FLOODING IN LOW LYING AREAS AND VIADUCTS LIKELY. THERE WILL ALSO
LIKELY BE FLOODING OF SMALL STREAMS AND SOME AREA RIVERS THAT HAVE
A REDUCED CAPACITY DUE TO PREVIOUS RAINFALL.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* STRONG/SEVERE THUNDERSTORM POTENTIAL LATE THIS AFTERNOON INTO
THIS EVENING THAT COULD HAVE SIGNIFICANT IMPACTS ON THE
TERMINALS...SHOWERS/THUNDERSTORMS INCREASING AFTER 21Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR/LIFR VIS
AND IFR CIGS POSSIBLE FOR A PERIOD.
* EAST NORTHEAST WINDS...THEN INCREASING LATER THIS EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
CONTINUE TO MONITOR THE POTENTIAL FOR SIGNIFICANT WEATHER TO AFFECT
THE TERMINALS LATER THIS AFTERNOON THROUGH THIS EVENING. ALTHOUGH
AT THIS TIME...RATHER QUIET ACROSS THE TERMINALS WITH VFR
CONDITIONS IN PLACE. WITH THE TRACK OF THE LOW THIS
MORNING...WINDS HAVE ACTUALLY BEEN ORIENTED MORE OUT OF A
SOUTHERLY DIRECTION TODAY. THIS WILL CONTINUE TO OCCUR WITH SOME
SPORADIC GUSTS BUT WITH A SHIFT BACK TO THE EAST NORTHEAST BY MID
AFTERNOON...WITH WINDS REMAINING MORE NORTHERLY THROUGH THE END OF
THE FORECAST PERIOD. DO EXPECT AN INCREASE IN ACTIVITY BY MID
AFTERNOON WITH SCATTERED SHOWERS/THUNDERSTORMS EXPECTED TO DEVELOP
ACROSS THE TERMINALS. THIS INITIAL ONSET IS EXPECTED TO ONLY HAVE
LIMITED IMPACTS ON THE TERMINALS BUT WITH THIS TO QUICKLY CHANGE
AS WE GO INTO THE LATE AFTERNOON. THUNDERSTORM DEVELOPMENT WILL
INCREASE WITH COVERAGE/INTENSITY OF THESE STORMS ALSO INCREASING
AS THEY SHIFT EAST ACROSS THE TERMINALS. NOT ONLY WILL LOWER
VIS/CEILINGS IN HEAVY RAIN WILL BE POSSIBLE...BUT STRONG/SHIFTING
WINDS ARE DEFINITELY POSSIBLE WITH THE STRONGEST THUNDERSTORMS
LATER THIS AFTERNOON. THIS WILL HAVE TO BE ADDRESSED WITH LATER
AMENDMENTS ONCE THUNDERSTORM INITIATION OCCURS AND THE FULL
THREAT OF CHANGING WEATHER FOR THE TERMINALS IS KNOWN.
SHOWERS/ISOLATED THUNDER SHOULD DIMINISH LATE THIS EVENING THROUGH
OVERNIGHT...WITH DRIER CONDITIONS EXPECTED EARLY THURSDAY MORNING
AS WELL AS CEILINGS IMPROVING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM TO HIGH CONFIDENCE WITH THUNDERSTORM TRENDS THIS
AFTERNOON THROUGH TONIGHT.
* MEDIUM TO HIGH CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL
WITH LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022 UNTIL 4 AM
THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002 UNTIL 4 AM THURSDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 PM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
254 PM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
243 PM CDT
COUPLE QUICK THOUGHTS ON SOME EVOLUTIONS IN THE MESOSCALE
ENVIRONMENT IN THE PAST 60 TO 90 MINS. DEEPER MIXING IN THE WARM
SECTOR IS ALLOWING SFC WINDS TO VEER CONSIDERABLY ACROSS THE WARM
SECTOR...WHICH IS SIGNIFICANTLY LOWERING THE LOW LEVEL SHEAR AND
POTENTIAL FOR LONG TRACK OR SIGNIFICANT TORNADOES IN THE WARM
SECTOR. WILL NEED TO MONITOR FOR ANY BACKING OF LOW LEVEL FLOW IN
THE WARM SECTOR THIS EVENING...BUT AT THIS POINT IN OUR CWA THE
MORE SIGNIFICANT TORNADO AND HIGH END WIND DAMAGE THREAT WOULD
LIKELY END UP NEAR THE SFC BOUNDARY STALLED OUT FROM ROUGHLY NEAR
CHICAGO WNW TO DBQ. THIS BOUNDARY MAY YET FLUCTUATE SOME THIS
AFTERNOON...BUT WHERE EVER THIS BOUNDARY ENDS UP IS WHERE THE
HIGHEST END SEVERE THREAT WILL LIKELY EXIST WITH SUPERCELL OR MORE
LIKELY WITH STRONG MV`S ALONG LEADING EDGE OF BOW THIS EVENING.
THE 1800 UTC SOUNDINGS FROM DVN AND ILX STILL SHOW A STRONG CAP
PRESENT...HOWEVER COMPARISON OF BOTH SOUNDINGS SHOW EVIDENCE OF
ASCENT TAKING PLACE AND BEGINNING TO LIFT THROUGH THE CAP. ALSO
SEEING EVIDENCE OF THIS ON VISIBLE SATELLITE IMAGERY WITH
GRADUALLY DEEPENING CU FIELD OVER NW IL. HAVE BEGUN TO SEE
CONVECTIVE INITIATION OVER NE IA ALREADY AND EXPECT MORE EXPLOSIVE
SEVERE THUNDERSTORM DEVELOPMENT TO TAKE PLACE WITHIN THE NEXT HOUR
OR TWO.
IZZI
130 PM CDT
THE MAIN THOUGHTS ON THE THREATS AND TIMING ON THE LIKELY SEVERE
WEATHER OUTBREAK REMAIN SIMILAR.
VISIBLE SATELLITE INDICATES MORE AGITATION IN THE ACCAS IN WEST-
TO-EAST BANDS ACROSS THE AREA WITH LIGHT ECHOES CONTINUING ON THE
RADAR MOSAIC. THESE ARE SIGNS OF THE ELEVATED WARM AIR ADVECTION
AND ACTUALLY ALREADY SOME MAMMATUS HAVE BEEN SEEN. STEEP LAPSE
RATES SEEN ON AMDAR DATA AND THE 18Z DVN RAOB ABOVE THIS LAYER
COULD SUPPORT SCATTERED CONVECTION DEVELOPING ACROSS NORTHERN IL
AND FAR NORTHWEST IN WITHIN THE NEXT TWO TO THREE HOURS.
OF GREATER CONCERN IS CONVECTIVE DEVELOPMENT LIKELY OVER NORTHEAST
IA/SOUTHWEST WI/NORTHWEST IL. THE PRIMARY 1004MB SURFACE LOW
ACROSS CENTRAL IA CONTINUES TO DEVELOP EAST WITH 5 MB/3 HR
PRESSURE FALLS CENTERED OVER THE CWA WHERE THE WARM FRONTAL
BOUNDARY HAS POSITIONED ITSELF. THIS BOUNDARY HAS UNDULATED
SOME...BUT APPEARS TO BE NORTH OF I-88 ESE INTO THE CHICAGO METRO
AREA...AND WILL POTENTIALLY BECOME MORE DEFINED WITH CLEARING
OCCURING ACROSS THE SOUTHERN FORECAST AREA. PRONOUNCED DRYING ON
WATER VAPOR AHEAD OF THE MAIN SHORT WAVE IN SOUTHERN MN AND A MID-
LEVEL WIND MAX WILL CONTINUE TO MOVE EAST AND OVERRIDE THE WARM
FRONTAL REGION ACROSS EASTERN IA SHORTLY. THE DEVELOPMENT OF
CONVECTION SEEN ON HIGH RESOLUTION GUIDANCE ALONG AND NORTH OF THE
WARM FRONT IN THIS AREA IS SUPPORTED BY OBSERVATIONAL
TRENDS...WITH THE DVN RAOB AND RAP ANALYSIS HAVING INDICATED THE
CAP TO BE ERODED.
THIS LIKELY DISCRETE DEVELOPMENT AT FIRST WILL AGAIN EVOLVE EAST
ACROSS NORTH CENTRAL IL AFTER MAINLY 4 PM. THE INSTABILITY AND
SHEAR SPECTRUM OF THE CURRENT ATMOSPHERE ARE NO PROBLEMS FOR
SEVERE STORMS...WITH HIGH CAPE GREATER THAN 2500 J/KG AND
EFFECTIVE DEEP LAYER SHEAR IN EXCESS OF 45 KTS. SUPERCELLS WILL
CERTAINLY BE SUPPORTED. SOME DEVELOPMENT EAST OF THE INITIAL
CELLS...POSSIBLY SURFACE BASED...MAY OCCUR TOO DEPENDING ON IF THE
CIN CAN ERODE AND THE CONVERGENCE ALONG THE SURFACE BOUNDARY IS
ENHANCED. THIS LENDS TO UNCERTAINTY ON WHEN THE FIRST ROBUST
ACTIVITY COULD REACH CHICAGO. BUT THE PRIMARY THREAT TIMES STILL
LOOK TO BE 4-7 PM IN AND AROUND ROCKFORD AND 6-11 PM IN CHICAGO.
OBSERVATIONAL TRENDS CONTINUE TO POINT TOWARDS THE POTENTIAL FOR A
ROBUST MCS...WITH WINDS POTENTIALLY 80 TO 100 MPH WINDS...DEVELOPING
ACROSS THE AREA THIS EVE. ALL INGREDIENTS ARE FAVORABLE FOR
THIS...INCLUDING A STRONG MID-LEVEL JET...SUFFICIENT 0-3 KM SHEAR
FOR COLD POOL ORGANIZATION...A LARGE AREA OF HIGH DOWNDRAFT
CAPE...AND A VEERING STRONG LOW-LEVEL JET INTO A EXISTING
BAROCLINIC GRADIENT. MANY OF THE CONVECTIVE ALLOWING GUIDANCE
INDICATE NOT ONLY MCV TYPE STRUCTURE ACROSS FAR NORTHERN IL RACING
INTO CHICAGO AND NORTHWEST IN THIS EVE...BUT ALSO AGREE ON HIGH
SURFACE-BASED WINDS. RAP AND NAM FORECASTS INTO TONIGHT FOR THE
ENVIRONMENT WOULD SUPPORT THIS AS WOULD THE CONCEPTUAL MODEL OF A
QUICKLY EASTWARD DEVELOPING SURFACE LOW. SOMETHING TO KEEP IN MIND
WITH THE POSSIBLE PATH OF THIS ACROSS FAR SOUTHERN LAKE MI IS THAT
A SEICHE WOULD BE FAVORED IF THAT WERE TO OCCUR. THE 12Z LOCAL ARW
ACTUALLY APPEARS TO HAVE THAT FORECAST IN THE PRESSURE FIELDS.
WILL MENTION THIS AND THE HIGHER ENDS WINDS OVER LAND IN THE HWO.+
&&
.DISCUSSION...
304 AM CDT
...MAJOR SEVERE WEATHER OUTBREAK LIKELY THIS AFTERNOON AND
EVENING...WITH HEAVY RAINFALL ALSO LIKELY...
EVERYTHING LINING UP FOR A SIGNIFICANT SEVERE WEATHER OUTBREAK
TODAY. SPC DAY 1 OUTLOOK HAS ENTIRE FORECAST AREA IN MODERATE RISK
OF SEVERE WITH SIGNIFICANT WIND...HAIL...AND TORNADO THREAT. AT THE
SURFACE...LOW PRESSURE OVER THE PLAINS WITH A WEAK WARM FRONT
EXTENDING EAST INTO NORTHERN IL EARLY THIS MORNING. THE LOW WILL
MOVE EAST ALONG THE IA/MO BOARDER TODAY...AND ACROSS NORTHERN IL
THIS EVENING. VERY MOIST LOW LEVEL AIR WITH SURFACE DEW POINTS IN
THE MID AND UPPER 60S IN PLACE. MAY SEE DEWPOINTS POOL IN THE LOWER
70S SOUTH OF WARM FRONT THIS AFTERNOON. THE BOUNDARY WILL INTENSIFY
AS SOUTHWEST LOW LEVEL FLOW INCREASES SOUTH OF THE FRONT AND SURFACE
WINDS BACK TO SE OR E NORTH OF THE BOUNDARY. THIS WILL PULL MODIFIED
MARINE AIR BACK ACROSS FAR NORTHERN IL. HAVE SOME CONCERNS ABOUT HOW
FAR NORTH THE WARM FRONT WILL TRAVEL. SPC DISCUSSION SUGGESTING THE
BOUNDARY WILL MOVE INTO SOUTHERN WI BUT WITH MODELS TAKING LOW
ACROSS I-80 CORRIDOR AND COOLING INFLUENCE OF LAKE
MICHIGAN...THINKING FRONT WONT GET MUCH FARTHER NORTH THAN A
DIXON-GARY LINE. THIS MAY LIMIT NORTHERN EXTEND OF SIGNIFICANT
SEVERE THREAT. THE BOUNDARY WILL ALSO RESULT IN A CHALLENGING
TEMPERATURE FORECAST...WITH TEMPS REACHING LOWER 90S FAR SOUTHERN
PART OF FORECAST AREA...WHILE AREAS ALONG THE NORTH SHORE WILL
LIKELY BE 20 DEGREES COOLER. IT APPEARS THAT MOST OF THE OVERNIGHT
EARLY MORNING CONVECTION WILL AFFECT WI...BUT KEEPING AN EYE ON
MCS OVER WESTERN IA WHICH COULD MOVE INTO NORTHERN IL THIS
MORNING. EARLIER CONVECTION OVER EASTERN IA WEAKENED AS IT MOVED
EAST AND THINK THIS MCS MAY DO THE SAME. CLOUD DEBRIS SHOULD
REMAIN NORTH ALLOWING AREAS SOUTH OF THE WARM FRONT TO HEAT UP
SIGNIFICANTLY...INTO THE UPPER 80S TO LOWER 90S. THIS COULD RESULT
IN SURFACE BASED CAPE OF 3000+ THIS AFTERNOON. FAIRLY VIGOROUS
SHORT WAVE MOVING INTO WESTERN SD/NE EARLY THIS MORNING WILL BE
MOVING ACROSS NORTHERN IL THIS EVENING. MODEL SOUNDINGS SHOW
FAIRLY STOUT CAP EARLY IN THE DAY ERODES THIS AFTERNOON WITH
APPROACHING SHORT WAVE. LOOKING AT 0-6KM BULK SHEAR 50-60 KTS BY
THIS EVENING. WITH INCREASING LOW LEVEL FLOW THIS AFTERNOON AND
BACKING SURFACE WINDS ALONG THE BOUNDARY...SHOULD PRODUCE AN
ENVIRONMENT FAVORABLE FOR DAMAGING WINDS...LARGE HAIL...AND
TORNADOES. SOME OF THE SHORT RANGE HI RES GUIDANCE IS SUGGESTING
DISCRETE STORMS INITIALLY THIS AFTERNOON. EXPECT THE TORNADO
THREAT TO BE MAINLY DURING THE AFTERNOON. STORMS WILL LIKELY
CONGEAL INTO AN MCS AND BECOME MORE OF A HIGH WIND WITH EMBEDDED
QLCS TORNADO THREAT IN THE EVENING. THE OTHER CONCERN IS WITH
PWATS AROUND 2 INCHES...AND SURFACE DEW POINTS NEAR
70...THUNDERSTORMS WILL BE CAPABLE OF VERY HEAVY RAINFALL AND AS
MCS DEVELOPS...FLOODING WILL ALSO BE A CONCERN. MODEL CONSENSUS IS
TO PLACE HEAVIEST QPF NORTH OF THE BOUNDARY OVER THE RFD AND
CHICAGO AREAS. SEE HYDRO SECTION OF THE AFD BELOW.
AFTER THE PASSAGE OF THIS SYSTEM...CENTRAL US RIDGE SHARPENS
BRINGING MUCH DRIER AND COOLER NORTHWEST FLOW FOR THU AND FRI.
EVENTUALLY PACNW UPPER LOW MOVES EAST ACROSS THE CANADIAN PRAIRIES
WHICH WILL PUSH THE RIDGE AXIS EASTWARD AND FLATTEN IT OUT. THUS A
FEW MORE ROUNDS OF THUNDERSTORMS ARE LIKELY TO RETURN SATURDAY AND
SUNDAY AND POSSIBLY INTO MONDAY BEFORE UPPER LOW OPENS INTO A
POTENT SHORT WAVE AND DROPS SOUTHEAST THROUGH THE GREAT LAKES.
ALLSOPP
&&
.HYDROLOGY...
HAVE ISSUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
DIXON TO VALPARAISO LINE. THERE IS THE POTENTIAL FOR WIDESPREAD HEAVY
RAINFALL OF 2 TO 3 INCHES ACROSS THIS AREA...WITH LOCALLY UP TO 5
INCHES. THE AXIS OF HEAVIEST RAIN WILL BE OVER THE HIGHLY
URBANIZED ROCKFORD AND CHICAGO METRO AREAS. ALSO CONCERNED FOR THE
POTENTIAL OF VERY HIGH RAINFALL RATES IN SOME OF THE HEAVIER DOWNPOURS.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* STRONG/SEVERE THUNDERSTORM POTENTIAL LATE THIS AFTERNOON INTO
THIS EVENING THAT COULD HAVE SIGNIFICANT IMPACTS ON THE
TERMINALS...SHOWERS/THUNDERSTORMS INCREASING AFTER 21Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR/LIFR VIS
AND IFR CIGS POSSIBLE FOR A PERIOD.
* EAST NORTHEAST WINDS...THEN INCREASING LATER THIS EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
CONTINUE TO MONITOR THE POTENTIAL FOR SIGNIFICANT WEATHER TO AFFECT
THE TERMINALS LATER THIS AFTERNOON THROUGH THIS EVENING. ALTHOUGH
AT THIS TIME...RATHER QUIET ACROSS THE TERMINALS WITH VFR
CONDITIONS IN PLACE. WITH THE TRACK OF THE LOW THIS
MORNING...WINDS HAVE ACTUALLY BEEN ORIENTED MORE OUT OF A
SOUTHERLY DIRECTION TODAY. THIS WILL CONTINUE TO OCCUR WITH SOME
SPORADIC GUSTS BUT WITH A SHIFT BACK TO THE EAST NORTHEAST BY MID
AFTERNOON...WITH WINDS REMAINING MORE NORTHERLY THROUGH THE END OF
THE FORECAST PERIOD. DO EXPECT AN INCREASE IN ACTIVITY BY MID
AFTERNOON WITH SCATTERED SHOWERS/THUNDERSTORMS EXPECTED TO DEVELOP
ACROSS THE TERMINALS. THIS INITIAL ONSET IS EXPECTED TO ONLY HAVE
LIMITED IMPACTS ON THE TERMINALS BUT WITH THIS TO QUICKLY CHANGE
AS WE GO INTO THE LATE AFTERNOON. THUNDERSTORM DEVELOPMENT WILL
INCREASE WITH COVERAGE/INTENSITY OF THESE STORMS ALSO INCREASING
AS THEY SHIFT EAST ACROSS THE TERMINALS. NOT ONLY WILL LOWER
VIS/CEILINGS IN HEAVY RAIN WILL BE POSSIBLE...BUT STRONG/SHIFTING
WINDS ARE DEFINITELY POSSIBLE WITH THE STRONGEST THUNDERSTORMS
LATER THIS AFTERNOON. THIS WILL HAVE TO BE ADDRESSED WITH LATER
AMENDMENTS ONCE THUNDERSTORM INITIATION OCCURS AND THE FULL
THREAT OF CHANGING WEATHER FOR THE TERMINALS IS KNOWN.
SHOWERS/ISOLATED THUNDER SHOULD DIMINISH LATE THIS EVENING THROUGH
OVERNIGHT...WITH DRIER CONDITIONS EXPECTED EARLY THURSDAY MORNING
AS WELL AS CEILINGS IMPROVING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM TO HIGH CONFIDENCE WITH THUNDERSTORM TRENDS THIS
AFTERNOON THROUGH TONIGHT.
* MEDIUM TO HIGH CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL
WITH LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022 UNTIL 4 AM
THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002 UNTIL 4 AM THURSDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 PM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
244 PM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
243 PM CDT
COUPLE QUICK THOUGHTS ON SOME EVOLUTIONS IN THE MESOSCALE
ENVIRONMENT IN THE PAST 60 TO 90 MINS. DEEPER MIXING IN THE WARM
SECTOR IS ALLOWING SFC WINDS TO VEER CONSIDERABLY ACROSS THE WARM
SECTOR...WHICH IS SIGNIFICANTLY LOWERING THE LOW LEVEL SHEAR AND
POTENTIAL FOR LONG TRACK OR SIGNIFICANT TORNADOES IN THE WARM
SECTOR. WILL NEED TO MONITOR FOR ANY BACKING OF LOW LEVEL FLOW IN
THE WARM SECTOR THIS EVENING...BUT AT THIS POINT IN OUR CWA THE
MORE SIGNIFICANT TORNADO AND HIGH END WIND DAMAGE THREAT WOULD
LIKELY END UP NEAR THE SFC BOUNDARY STALLED OUT FROM ROUGHLY NEAR
CHICAGO WNW TO DBQ. THIS BOUNDARY MAY YET FLUCTUATE SOME THIS
AFTERNOON...BUT WHERE EVER THIS BOUNDARY ENDS UP IS WHERE THE
HIGHEST END SEVERE THREAT WILL LIKELY EXIST WITH SUPERCELL OR MORE
LIKELY WITH STRONG MV`S ALONG LEADING EDGE OF BOW THIS EVENING.
THE 1800 UTC SOUNDINGS FROM DVN AND ILX STILL SHOW A STRONG CAP
PRESENT...HOWEVER COMPARISON OF BOTH SOUNDINGS SHOW EVIDENCE OF
ASCENT TAKING PLACE AND BEGINNING TO LIFT THROUGH THE CAP. ALSO
SEEING EVIDENCE OF THIS ON VISIBLE SATELLITE IMAGERY WITH
GRADUALLY DEEPENING CU FIELD OVER NW IL. HAVE BEGUN TO SEE
CONVECTIVE INITIATION OVER NE IA ALREADY AND EXPECT MORE EXPLOSIVE
SEVERE THUNDERSTORM DEVELOPMENT TO TAKE PLACE WITHIN THE NEXT HOUR
OR TWO.
IZZI
130 PM CDT
THE MAIN THOUGHTS ON THE THREATS AND TIMING ON THE LIKELY SEVERE
WEATHER OUTBREAK REMAIN SIMILAR.
VISIBLE SATELLITE INDICATES MORE AGITATION IN THE ACCAS IN WEST-
TO-EAST BANDS ACROSS THE AREA WITH LIGHT ECHOES CONTINUING ON THE
RADAR MOSAIC. THESE ARE SIGNS OF THE ELEVATED WARM AIR ADVECTION
AND ACTUALLY ALREADY SOME MAMMATUS HAVE BEEN SEEN. STEEP LAPSE
RATES SEEN ON AMDAR DATA AND THE 18Z DVN RAOB ABOVE THIS LAYER
COULD SUPPORT SCATTERED CONVECTION DEVELOPING ACROSS NORTHERN IL
AND FAR NORTHWEST IN WITHIN THE NEXT TWO TO THREE HOURS.
OF GREATER CONCERN IS CONVECTIVE DEVELOPMENT LIKELY OVER NORTHEAST
IA/SOUTHWEST WI/NORTHWEST IL. THE PRIMARY 1004MB SURFACE LOW
ACROSS CENTRAL IA CONTINUES TO DEVELOP EAST WITH 5 MB/3 HR
PRESSURE FALLS CENTERED OVER THE CWA WHERE THE WARM FRONTAL
BOUNDARY HAS POSITIONED ITSELF. THIS BOUNDARY HAS UNDULATED
SOME...BUT APPEARS TO BE NORTH OF I-88 ESE INTO THE CHICAGO METRO
AREA...AND WILL POTENTIALLY BECOME MORE DEFINED WITH CLEARING
OCCURING ACROSS THE SOUTHERN FORECAST AREA. PRONOUNCED DRYING ON
WATER VAPOR AHEAD OF THE MAIN SHORT WAVE IN SOUTHERN MN AND A MID-
LEVEL WIND MAX WILL CONTINUE TO MOVE EAST AND OVERRIDE THE WARM
FRONTAL REGION ACROSS EASTERN IA SHORTLY. THE DEVELOPMENT OF
CONVECTION SEEN ON HIGH RESOLUTION GUIDANCE ALONG AND NORTH OF THE
WARM FRONT IN THIS AREA IS SUPPORTED BY OBSERVATIONAL
TRENDS...WITH THE DVN RAOB AND RAP ANALYSIS HAVING INDICATED THE
CAP TO BE ERODED.
THIS LIKELY DISCRETE DEVELOPMENT AT FIRST WILL AGAIN EVOLVE EAST
ACROSS NORTH CENTRAL IL AFTER MAINLY 4 PM. THE INSTABILITY AND
SHEAR SPECTRUM OF THE CURRENT ATMOSPHERE ARE NO PROBLEMS FOR
SEVERE STORMS...WITH HIGH CAPE GREATER THAN 2500 J/KG AND
EFFECTIVE DEEP LAYER SHEAR IN EXCESS OF 45 KTS. SUPERCELLS WILL
CERTAINLY BE SUPPORTED. SOME DEVELOPMENT EAST OF THE INITIAL
CELLS...POSSIBLY SURFACE BASED...MAY OCCUR TOO DEPENDING ON IF THE
CIN CAN ERODE AND THE CONVERGENCE ALONG THE SURFACE BOUNDARY IS
ENHANCED. THIS LENDS TO UNCERTAINTY ON WHEN THE FIRST ROBUST
ACTIVITY COULD REACH CHICAGO. BUT THE PRIMARY THREAT TIMES STILL
LOOK TO BE 4-7 PM IN AND AROUND ROCKFORD AND 6-11 PM IN CHICAGO.
OBSERVATIONAL TRENDS CONTINUE TO POINT TOWARDS THE POTENTIAL FOR A
ROBUST MCS...WITH WINDS POTENTIALLY 80 TO 100 MPH WINDS...DEVELOPING
ACROSS THE AREA THIS EVE. ALL INGREDIENTS ARE FAVORABLE FOR
THIS...INCLUDING A STRONG MID-LEVEL JET...SUFFICIENT 0-3 KM SHEAR
FOR COLD POOL ORGANIZATION...A LARGE AREA OF HIGH DOWNDRAFT
CAPE...AND A VEERING STRONG LOW-LEVEL JET INTO A EXISTING
BAROCLINIC GRADIENT. MANY OF THE CONVECTIVE ALLOWING GUIDANCE
INDICATE NOT ONLY MCV TYPE STRUCTURE ACROSS FAR NORTHERN IL RACING
INTO CHICAGO AND NORTHWEST IN THIS EVE...BUT ALSO AGREE ON HIGH
SURFACE-BASED WINDS. RAP AND NAM FORECASTS INTO TONIGHT FOR THE
ENVIRONMENT WOULD SUPPORT THIS AS WOULD THE CONCEPTUAL MODEL OF A
QUICKLY EASTWARD DEVELOPING SURFACE LOW. SOMETHING TO KEEP IN MIND
WITH THE POSSIBLE PATH OF THIS ACROSS FAR SOUTHERN LAKE MI IS THAT
A SEICHE WOULD BE FAVORED IF THAT WERE TO OCCUR. THE 12Z LOCAL ARW
ACTUALLY APPEARS TO HAVE THAT FORECAST IN THE PRESSURE FIELDS.
WILL MENTION THIS AND THE HIGHER ENDS WINDS OVER LAND IN THE HWO.+
&&
.DISCUSSION...
304 AM CDT
...MAJOR SEVERE WEATHER OUTBREAK LIKELY THIS AFTERNOON AND
EVENING...WITH HEAVY RAINFALL ALSO LIKELY...
EVERYTHING LINING UP FOR A SIGNIFICANT SEVERE WEATHER OUTBREAK
TODAY. SPC DAY 1 OUTLOOK HAS ENTIRE FORECAST AREA IN MODERATE RISK
OF SEVERE WITH SIGNIFICANT WIND...HAIL...AND TORNADO THREAT. AT THE
SURFACE...LOW PRESSURE OVER THE PLAINS WITH A WEAK WARM FRONT
EXTENDING EAST INTO NORTHERN IL EARLY THIS MORNING. THE LOW WILL
MOVE EAST ALONG THE IA/MO BOARDER TODAY...AND ACROSS NORTHERN IL
THIS EVENING. VERY MOIST LOW LEVEL AIR WITH SURFACE DEW POINTS IN
THE MID AND UPPER 60S IN PLACE. MAY SEE DEWPOINTS POOL IN THE LOWER
70S SOUTH OF WARM FRONT THIS AFTERNOON. THE BOUNDARY WILL INTENSIFY
AS SOUTHWEST LOW LEVEL FLOW INCREASES SOUTH OF THE FRONT AND SURFACE
WINDS BACK TO SE OR E NORTH OF THE BOUNDARY. THIS WILL PULL MODIFIED
MARINE AIR BACK ACROSS FAR NORTHERN IL. HAVE SOME CONCERNS ABOUT HOW
FAR NORTH THE WARM FRONT WILL TRAVEL. SPC DISCUSSION SUGGESTING THE
BOUNDARY WILL MOVE INTO SOUTHERN WI BUT WITH MODELS TAKING LOW
ACROSS I-80 CORRIDOR AND COOLING INFLUENCE OF LAKE
MICHIGAN...THINKING FRONT WONT GET MUCH FARTHER NORTH THAN A
DIXON-GARY LINE. THIS MAY LIMIT NORTHERN EXTEND OF SIGNIFICANT
SEVERE THREAT. THE BOUNDARY WILL ALSO RESULT IN A CHALLENGING
TEMPERATURE FORECAST...WITH TEMPS REACHING LOWER 90S FAR SOUTHERN
PART OF FORECAST AREA...WHILE AREAS ALONG THE NORTH SHORE WILL
LIKELY BE 20 DEGREES COOLER. IT APPEARS THAT MOST OF THE OVERNIGHT
EARLY MORNING CONVECTION WILL AFFECT WI...BUT KEEPING AN EYE ON
MCS OVER WESTERN IA WHICH COULD MOVE INTO NORTHERN IL THIS
MORNING. EARLIER CONVECTION OVER EASTERN IA WEAKENED AS IT MOVED
EAST AND THINK THIS MCS MAY DO THE SAME. CLOUD DEBRIS SHOULD
REMAIN NORTH ALLOWING AREAS SOUTH OF THE WARM FRONT TO HEAT UP
SIGNIFICANTLY...INTO THE UPPER 80S TO LOWER 90S. THIS COULD RESULT
IN SURFACE BASED CAPE OF 3000+ THIS AFTERNOON. FAIRLY VIGOROUS
SHORT WAVE MOVING INTO WESTERN SD/NE EARLY THIS MORNING WILL BE
MOVING ACROSS NORTHERN IL THIS EVENING. MODEL SOUNDINGS SHOW
FAIRLY STOUT CAP EARLY IN THE DAY ERODES THIS AFTERNOON WITH
APPROACHING SHORT WAVE. LOOKING AT 0-6KM BULK SHEAR 50-60 KTS BY
THIS EVENING. WITH INCREASING LOW LEVEL FLOW THIS AFTERNOON AND
BACKING SURFACE WINDS ALONG THE BOUNDARY...SHOULD PRODUCE AN
ENVIRONMENT FAVORABLE FOR DAMAGING WINDS...LARGE HAIL...AND
TORNADOES. SOME OF THE SHORT RANGE HI RES GUIDANCE IS SUGGESTING
DISCRETE STORMS INITIALLY THIS AFTERNOON. EXPECT THE TORNADO
THREAT TO BE MAINLY DURING THE AFTERNOON. STORMS WILL LIKELY
CONGEAL INTO AN MCS AND BECOME MORE OF A HIGH WIND WITH EMBEDDED
QLCS TORNADO THREAT IN THE EVENING. THE OTHER CONCERN IS WITH
PWATS AROUND 2 INCHES...AND SURFACE DEW POINTS NEAR
70...THUNDERSTORMS WILL BE CAPABLE OF VERY HEAVY RAINFALL AND AS
MCS DEVELOPS...FLOODING WILL ALSO BE A CONCERN. MODEL CONSENSUS IS
TO PLACE HEAVIEST QPF NORTH OF THE BOUNDARY OVER THE RFD AND
CHICAGO AREAS. SEE HYDRO SECTION OF THE AFD BELOW.
AFTER THE PASSAGE OF THIS SYSTEM...CENTRAL US RIDGE SHARPENS
BRINGING MUCH DRIER AND COOLER NORTHWEST FLOW FOR THU AND FRI.
EVENTUALLY PACNW UPPER LOW MOVES EAST ACROSS THE CANADIAN PRAIRIES
WHICH WILL PUSH THE RIDGE AXIS EASTWARD AND FLATTEN IT OUT. THUS A
FEW MORE ROUNDS OF THUNDERSTORMS ARE LIKELY TO RETURN SATURDAY AND
SUNDAY AND POSSIBLY INTO MONDAY BEFORE UPPER LOW OPENS INTO A
POTENT SHORT WAVE AND DROPS SOUTHEAST THROUGH THE GREAT LAKES.
ALLSOPP
&&
.HYDROLOGY...
HAVE ISSUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
DIXON TO VALPARAISO LINE. THERE IS THE POTENTIAL FOR WIDESPREAD HEAVY
RAINFALL OF 2 TO 3 INCHES ACROSS THIS AREA...WITH LOCALLY UP TO 5
INCHES. THE AXIS OF HEAVIEST RAIN WILL BE OVER THE HIGHLY
URBANIZED ROCKFORD AND CHICAGO METRO AREAS. ALSO CONCERNED FOR THE
POTENTIAL OF VERY HIGH RAINFALL RATES IN SOME OF THE HEAVIER DOWNPOURS.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* STRONG/SEVERE THUNDERSTORM POTENTIAL LATE THIS AFTERNOON INTO
THIS EVENING THAT COULD HAVE SIGNIFICANT IMPACTS ON THE
TERMINALS...SHOWERS/THUNDERSTORMS INCREASING AFTER 20Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR/LIFR VIS
AND IFR CIGS POSSIBLE FOR A PERIOD.
* SOUTHERLY WINDS WITH GUSTS IN THE MID/UPPER TEENS POSSIBLE
BEFORE WINDS ARE EXPECTED TO GO BACK TO THE EAST NORTHEAST BY
MID AFTERNOON...THEN INCREASING OUT OF THE NORTH/NORTHEAST THIS
EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
CONTINUE TO MONITOR THE POTENTIAL FOR SIGNIFICANT WEATHER TO AFFECT
THE TERMINALS LATER THIS AFTERNOON THROUGH THIS EVENING. ALTHOUGH
AT THIS TIME...RATHER QUIET ACROSS THE TERMINALS WITH VFR
CONDITIONS IN PLACE. WITH THE TRACK OF THE LOW THIS
MORNING...WINDS HAVE ACTUALLY BEEN ORIENTED MORE OUT OF A
SOUTHERLY DIRECTION TODAY. THIS WILL CONTINUE TO OCCUR WITH SOME
SPORADIC GUSTS BUT WITH A SHIFT BACK TO THE EAST NORTHEAST BY MID
AFTERNOON...WITH WINDS REMAINING MORE NORTHERLY THROUGH THE END OF
THE FORECAST PERIOD. DO EXPECT AN INCREASE IN ACTIVITY BY MID
AFTERNOON WITH SCATTERED SHOWERS/THUNDERSTORMS EXPECTED TO DEVELOP
ACROSS THE TERMINALS. THIS INITIAL ONSET IS EXPECTED TO ONLY HAVE
LIMITED IMPACTS ON THE TERMINALS BUT WITH THIS TO QUICKLY CHANGE
AS WE GO INTO THE LATE AFTERNOON. THUNDERSTORM DEVELOPMENT WILL
INCREASE WITH COVERAGE/INTENSITY OF THESE STORMS ALSO INCREASING
AS THEY SHIFT EAST ACROSS THE TERMINALS. NOT ONLY WILL LOWER
VIS/CEILINGS IN HEAVY RAIN WILL BE POSSIBLE...BUT STRONG/SHIFTING
WINDS ARE DEFINITELY POSSIBLE WITH THE STRONGEST THUNDERSTORMS
LATER THIS AFTERNOON. THIS WILL HAVE TO BE ADDRESSED WITH LATER
AMENDMENTS ONCE THUNDERSTORM INITIATION OCCURS AND THE FULL
THREAT OF CHANGING WEATHER FOR THE TERMINALS IS KNOWN.
SHOWERS/ISOLATED THUNDER SHOULD DIMINISH LATE THIS EVENING THROUGH
OVERNIGHT...WITH DRIER CONDITIONS EXPECTED EARLY THURSDAY MORNING
AS WELL AS CEILINGS IMPROVING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN CHANCES FOR THUNDERSTORMS LATER
TODAY AND TONIGHT...BUT MEDIUM CONFIDENCE ON THE ONSET TIMING.
* MEDIUM TO HIGH CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL
WITH LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022 UNTIL 4 AM
THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002 UNTIL 4 AM THURSDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 PM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
129 PM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
130 PM CDT
THE MAIN THOUGHTS ON THE THREATS AND TIMING ON THE LIKELY SEVERE
WEATHER OUTBREAK REMAIN SIMILAR.
VISIBLE SATELLITE INDICATES MORE AGITATION IN THE ACCAS IN WEST-
TO-EAST BANDS ACROSS THE AREA WITH LIGHT ECHOES CONTINUING ON THE
RADAR MOSAIC. THESE ARE SIGNS OF THE ELEVATED WARM AIR ADVECTION
AND ACTUALLY ALREADY SOME MAMMATUS HAVE BEEN SEEN. STEEP LAPSE
RATES SEEN ON AMDAR DATA AND THE 18Z DVN RAOB ABOVE THIS LAYER
COULD SUPPORT SCATTERED CONVECTION DEVELOPING ACROSS NORTHERN IL
AND FAR NORTHWEST IN WITHIN THE NEXT TWO TO THREE HOURS.
OF GREATER CONCERN IS CONVECTIVE DEVELOPMENT LIKELY OVER NORTHEAST
IA/SOUTHWEST WI/NORTHWEST IL. THE PRIMARY 1004MB SURFACE LOW
ACROSS CENTRAL IA CONTINUES TO DEVELOP EAST WITH 5 MB/3 HR
PRESSURE FALLS CENTERED OVER THE CWA WHERE THE WARM FRONTAL
BOUNDARY HAS POSITIONED ITSELF. THIS BOUNDARY HAS UNDULATED
SOME...BUT APPEARS TO BE NORTH OF I-88 ESE INTO THE CHICAGO METRO
AREA...AND WILL POTENTIALLY BECOME MORE DEFINED WITH CLEARING
OCCURING ACROSS THE SOUTHERN FORECAST AREA. PRONOUNCED DRYING ON
WATER VAPOR AHEAD OF THE MAIN SHORT WAVE IN SOUTHERN MN AND A MID-
LEVEL WIND MAX WILL CONTINUE TO MOVE EAST AND OVERRIDE THE WARM
FRONTAL REGION ACROSS EASTERN IA SHORTLY. THE DEVELOPMENT OF
CONVECTION SEEN ON HIGH RESOLUTION GUIDANCE ALONG AND NORTH OF THE
WARM FRONT IN THIS AREA IS SUPPORTED BY OBSERVATIONAL
TRENDS...WITH THE DVN RAOB AND RAP ANALYSIS HAVING INDICATED THE
CAP TO BE ERODED.
THIS LIKELY DISCRETE DEVELOPMENT AT FIRST WILL AGAIN EVOLVE EAST
ACROSS NORTH CENTRAL IL AFTER MAINLY 4 PM. THE INSTABILITY AND
SHEAR SPECTRUM OF THE CURRENT ATMOSPHERE ARE NO PROBLEMS FOR
SEVERE STORMS...WITH HIGH CAPE GREATER THAN 2500 J/KG AND
EFFECTIVE DEEP LAYER SHEAR IN EXCESS OF 45 KTS. SUPERCELLS WILL
CERTAINLY BE SUPPORTED. SOME DEVELOPMENT EAST OF THE INITIAL
CELLS...POSSIBLY SURFACE BASED...MAY OCCUR TOO DEPENDING ON IF THE
CIN CAN ERODE AND THE CONVERGENCE ALONG THE SURFACE BOUNDARY IS
ENHANCED. THIS LENDS TO UNCERTAINTY ON WHEN THE FIRST ROBUST
ACTIVITY COULD REACH CHICAGO. BUT THE PRIMARY THREAT TIMES STILL
LOOK TO BE 4-7 PM IN AND AROUND ROCKFORD AND 6-11 PM IN CHICAGO.
OBSERVATIONAL TRENDS CONTINUE TO POINT TOWARDS THE POTENTIAL FOR A
ROBUST MCS...WITH WINDS POTENTIALLY 80 TO 100 MPH WINDS...DEVELOPING
ACROSS THE AREA THIS EVE. ALL INGREDIENTS ARE FAVORABLE FOR
THIS...INCLUDING A STRONG MID-LEVEL JET...SUFFICIENT 0-3 KM SHEAR
FOR COLD POOL ORGANIZATION...A LARGE AREA OF HIGH DOWNDRAFT
CAPE...AND A VEERING STRONG LOW-LEVEL JET INTO A EXISTING
BAROCLINIC GRADIENT. MANY OF THE CONVECTIVE ALLOWING GUIDANCE
INDICATE NOT ONLY MCV TYPE STRUCTURE ACROSS FAR NORTHERN IL RACING
INTO CHICAGO AND NORTHWEST IN THIS EVE...BUT ALSO AGREE ON HIGH
SURFACE-BASED WINDS. RAP AND NAM FORECASTS INTO TONIGHT FOR THE
ENVIRONMENT WOULD SUPPORT THIS AS WOULD THE CONCEPTUAL MODEL OF A
QUICKLY EASTWARD DEVELOPING SURFACE LOW. SOMETHING TO KEEP IN MIND
WITH THE POSSIBLE PATH OF THIS ACROSS FAR SOUTHERN LAKE MI IS THAT
A SEICHE WOULD BE FAVORED IF THAT WERE TO OCCUR. THE 12Z LOCAL ARW
ACTUALLY APPEARS TO HAVE THAT FORECAST IN THE PRESSURE FIELDS.
WILL MENTION THIS AND THE HIGHER ENDS WINDS OVER LAND IN THE HWO.+
.MESOSCALE DISCUSSION...
1042 AM CDT
...WIDESPREAD SEVERE WEATHER OUTBREAK ACROSS THE REGION EXPECTED
LATE THIS AFTERNOON AND EVENING INCLUDING TORNADIC POTENTIAL IN
NORTH CENTRAL IL LATE THIS AFTERNOON...
SEVERE WEATHER THREAT CONTINUES WITH OBSERVATIONAL TRENDS HINTING
MORE AT PRECISE EVOLUTION AND TIMING.
WHAT LEFTS OF OVERNIGHT DECAYING MCS IS MOVING FROM SOUTHEAST WI
OVER LAKE MI. VISIBLE SATELLITE AND REGIONAL RADAR MOSAIC
INDICATE SOME BRIEF SUPPRESSION BEHIND THIS WHILE THERE IS AN AXIS
EXTENDING SOUTHWARD ON RADAR OF LIKELY SOME MID-LEVEL CONVERGENCE.
THERE HAS NOT BEEN ANY DEVELOPMENT ALONG THIS THUS FAR BUT CANNOT
RULE OUT A FEW ELEVATED STORMS THROUGH 3 PM OR SO ACROSS FAR
NORTHERN AND NORTHEAST IL.
THE SURFACE LOW PRESSURE IS DEVELOPING NORTHEASTWARD INTO SOUTHWEST
AND CENTRAL IA AS OF 10 AM WITH A WARM FRONT EVOLVING EAST
NORTHEAST FROM THERE. THIS LOOKS TO BE FROM NEAR WATERLOO IA TO
SAVANNA IL AND THEN BECOMING MORE ILL-DEFINED EAST OF THERE INTO
THE CWA. DEW POINTS IN THE LOWER 70S ARE ADVECTING UP TO THIS
BOUNDARY WITH WINDS STRONGLY BACKED TO THE NORTH OF THIS. THERE
HAS BEEN GROWTH IN THE CU ACROSS IA NEAR THIS DEVELOPING FRONT.
AS THE MAIN VORT MAX AND MID-LEVEL SPEED MAX MOVE EAST FROM
EASTERN SD/NORTHEAST NE...DEVELOPMENT OF ROBUST CONVECTION IS
HIGHLY LIKELY BY MID AFTERNOON ACROSS NE IA/SW WI/NW IL. SUPERCELL
DEVELOPMENT WOULD BE A FAVORED MODE ALONG AND IMMEDIATELY NORTH OF
THE WARM FRONT. FURTHER NORTH AND NORTHEAST FROM THE TWIN CITIES
TO MILWAUKEE...ELEVATED CONVECTION MAY INCREASE. ALL OF THIS IS
SLIGHTLY FURTHER NORTH THAN EARLIER ANTICIPATED...BUT THE SEVERE
WEATHER THREAT HAS NOT DIMINISHED FOR OUR AREA...JUST FOCUSED MORE
SO IN THE LATE AFTERNOON AND EVE.
GIVEN THE ANTICIPATED EVOLUTION MENTIONED ABOVE WHICH HAS THE
SUPPORT OF THE RAP AND SEVERAL CONVECTIVE-ALLOWING MODELS...NORTH
CENTRAL IL WILL LIKELY BE UNDER THE GUN LATE THIS AFTERNOON. THIS
INCLUDES THE ROCKFORD AREA DURING RUSH HOUR AS STORMS EVOLVE
EASTWARD IN A FAVORED COMBINATION OF DISCRETE TO SMALL SCALE
CLUSTERS. TORNADIC POTENTIAL WILL CERTAINLY EXIST WITH THESE GIVEN
THE HELICITY RICH AIR NEAR THE BOUNDARY AND ANTICIPATED SURFACE-
BASED CAPE. CONVECTIVE TEMPERATURES FOR THIS ARE FORECAST TO BE
AROUND 80 DEGREES ON THE RAP. WHILE TEMPERATURE TRENDS HAVE BEEN
SLOW TO CLIMB ACROSS THE AREA THUS FAR...SOME THINNING OF THE
CLOUDS AND THE NORTHWARD PUSH OF THE WARM SECTOR SHOULD ALLOW THAT
TO OCCUR.
THE EVENING TIME PERIOD SHOULD SEE THE MOST COVERAGE OF SEVERE
CONVECTION IN THE FORECAST AREA AND WILL BE THE PRIME TIME FOR
CHICAGOLAND. THE LOW-LEVEL JET IS FORECAST TO INCREASE TO 40-50 KT
AND POINT INTO THE ONGOING CONVECTION. SOME SCATTERED CONVECTIVE
DEVELOPMENT...POTENTIALLY SEVERE AND SURFACE BASED...EAST AND
SOUTH OF THIS IS FAVORED DURING THE EVE. SUFFICIENT DEEP LAYER
SHEAR AND RICH LOW-LEVEL MOISTURE WILL OFFER AMPLE WIND THREAT
WITH THE ORGANIZED CONVECTIVE CLUSTERS. WITH THE SURFACE LOW
PROJECTED TO TRACK EAST NEAR THE I-88 CORRIDOR...THERE IS
INCREASING LIKELIHOOD THAT THE MAIN MCV/MCS WILL DEVELOP NEAR THIS
CORRIDOR AS WELL. A MAJORITY OF THE EXPLICIT GUIDANCE DOES
INDICATE THIS. VERY HEAVY RAINFALL AND AN ENHANCED WIND THREAT
WILL EXIST WITH THIS...WHICH WOULD LIKELY IMPACT CHICAGO IN THE
6-10 PM TIME FRAME.
MTF
&&
.DISCUSSION...
304 AM CDT
...MAJOR SEVERE WEATHER OUTBREAK LIKELY THIS AFTERNOON AND
EVENING...WITH HEAVY RAINFALL ALSO LIKELY...
EVERYTHING LINING UP FOR A SIGNIFICANT SEVERE WEATHER OUTBREAK
TODAY. SPC DAY 1 OUTLOOK HAS ENTIRE FORECAST AREA IN MODERATE RISK
OF SEVERE WITH SIGNIFICANT WIND...HAIL...AND TORNADO THREAT. AT THE
SURFACE...LOW PRESSURE OVER THE PLAINS WITH A WEAK WARM FRONT
EXTENDING EAST INTO NORTHERN IL EARLY THIS MORNING. THE LOW WILL
MOVE EAST ALONG THE IA/MO BOARDER TODAY...AND ACROSS NORTHERN IL
THIS EVENING. VERY MOIST LOW LEVEL AIR WITH SURFACE DEW POINTS IN
THE MID AND UPPER 60S IN PLACE. MAY SEE DEWPOINTS POOL IN THE LOWER
70S SOUTH OF WARM FRONT THIS AFTERNOON. THE BOUNDARY WILL INTENSIFY
AS SOUTHWEST LOW LEVEL FLOW INCREASES SOUTH OF THE FRONT AND SURFACE
WINDS BACK TO SE OR E NORTH OF THE BOUNDARY. THIS WILL PULL MODIFIED
MARINE AIR BACK ACROSS FAR NORTHERN IL. HAVE SOME CONCERNS ABOUT HOW
FAR NORTH THE WARM FRONT WILL TRAVEL. SPC DISCUSSION SUGGESTING THE
BOUNDARY WILL MOVE INTO SOUTHERN WI BUT WITH MODELS TAKING LOW
ACROSS I-80 CORRIDOR AND COOLING INFLUENCE OF LAKE
MICHIGAN...THINKING FRONT WONT GET MUCH FARTHER NORTH THAN A
DIXON-GARY LINE. THIS MAY LIMIT NORTHERN EXTEND OF SIGNIFICANT
SEVERE THREAT. THE BOUNDARY WILL ALSO RESULT IN A CHALLENGING
TEMPERATURE FORECAST...WITH TEMPS REACHING LOWER 90S FAR SOUTHERN
PART OF FORECAST AREA...WHILE AREAS ALONG THE NORTH SHORE WILL
LIKELY BE 20 DEGREES COOLER. IT APPEARS THAT MOST OF THE OVERNIGHT
EARLY MORNING CONVECTION WILL AFFECT WI...BUT KEEPING AN EYE ON
MCS OVER WESTERN IA WHICH COULD MOVE INTO NORTHERN IL THIS
MORNING. EARLIER CONVECTION OVER EASTERN IA WEAKENED AS IT MOVED
EAST AND THINK THIS MCS MAY DO THE SAME. CLOUD DEBRIS SHOULD
REMAIN NORTH ALLOWING AREAS SOUTH OF THE WARM FRONT TO HEAT UP
SIGNIFICANTLY...INTO THE UPPER 80S TO LOWER 90S. THIS COULD RESULT
IN SURFACE BASED CAPE OF 3000+ THIS AFTERNOON. FAIRLY VIGOROUS
SHORT WAVE MOVING INTO WESTERN SD/NE EARLY THIS MORNING WILL BE
MOVING ACROSS NORTHERN IL THIS EVENING. MODEL SOUNDINGS SHOW
FAIRLY STOUT CAP EARLY IN THE DAY ERODES THIS AFTERNOON WITH
APPROACHING SHORT WAVE. LOOKING AT 0-6KM BULK SHEAR 50-60 KTS BY
THIS EVENING. WITH INCREASING LOW LEVEL FLOW THIS AFTERNOON AND
BACKING SURFACE WINDS ALONG THE BOUNDARY...SHOULD PRODUCE AN
ENVIRONMENT FAVORABLE FOR DAMAGING WINDS...LARGE HAIL...AND
TORNADOES. SOME OF THE SHORT RANGE HI RES GUIDANCE IS SUGGESTING
DISCRETE STORMS INITIALLY THIS AFTERNOON. EXPECT THE TORNADO
THREAT TO BE MAINLY DURING THE AFTERNOON. STORMS WILL LIKELY
CONGEAL INTO AN MCS AND BECOME MORE OF A HIGH WIND WITH EMBEDDED
QLCS TORNADO THREAT IN THE EVENING. THE OTHER CONCERN IS WITH
PWATS AROUND 2 INCHES...AND SURFACE DEW POINTS NEAR
70...THUNDERSTORMS WILL BE CAPABLE OF VERY HEAVY RAINFALL AND AS
MCS DEVELOPS...FLOODING WILL ALSO BE A CONCERN. MODEL CONSENSUS IS
TO PLACE HEAVIEST QPF NORTH OF THE BOUNDARY OVER THE RFD AND
CHICAGO AREAS. SEE HYDRO SECTION OF THE AFD BELOW.
AFTER THE PASSAGE OF THIS SYSTEM...CENTRAL US RIDGE SHARPENS
BRINGING MUCH DRIER AND COOLER NORTHWEST FLOW FOR THU AND FRI.
EVENTUALLY PACNW UPPER LOW MOVES EAST ACROSS THE CANADIAN PRAIRIES
WHICH WILL PUSH THE RIDGE AXIS EASTWARD AND FLATTEN IT OUT. THUS A
FEW MORE ROUNDS OF THUNDERSTORMS ARE LIKELY TO RETURN SATURDAY AND
SUNDAY AND POSSIBLY INTO MONDAY BEFORE UPPER LOW OPENS INTO A
POTENT SHORT WAVE AND DROPS SOUTHEAST THROUGH THE GREAT LAKES.
ALLSOPP
&&
.HYDROLOGY...
HAVE ISSUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
DIXON TO VALPARAISO LINE. THERE IS THE POTENTIAL FOR WIDESPREAD HEAVY
RAINFALL OF 2 TO 3 INCHES ACROSS THIS AREA...WITH LOCALLY UP TO 5
INCHES. THE AXIS OF HEAVIEST RAIN WILL BE OVER THE HIGHLY
URBANIZED ROCKFORD AND CHICAGO METRO AREAS. ALSO CONCERNED FOR THE
POTENTIAL OF VERY HIGH RAINFALL RATES IN SOME OF THE HEAVIER DOWNPOURS.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* STRONG/SEVERE THUNDERSTORM POTENTIAL LATE THIS AFTERNOON INTO
THIS EVENING THAT COULD HAVE SIGNIFICANT IMPACTS ON THE
TERMINALS...SHOWERS/THUNDERSTORMS INCREASING AFTER 20Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR/LIFR VIS
AND IFR CIGS POSSIBLE FOR A PERIOD.
* SOUTHERLY WINDS WITH GUSTS IN THE MID/UPPER TEENS POSSIBLE
BEFORE WINDS ARE EXPECTED TO GO BACK TO THE EAST NORTHEAST BY
MID AFTERNOON...THEN INCREASING OUT OF THE NORTH/NORTHEAST THIS
EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
CONTINUE TO MONITOR THE POTENTIAL FOR SIGNIFICANT WEATHER TO AFFECT
THE TERMINALS LATER THIS AFTERNOON THROUGH THIS EVENING. ALTHOUGH
AT THIS TIME...RATHER QUIET ACROSS THE TERMINALS WITH VFR
CONDITIONS IN PLACE. WITH THE TRACK OF THE LOW THIS
MORNING...WINDS HAVE ACTUALLY BEEN ORIENTED MORE OUT OF A
SOUTHERLY DIRECTION TODAY. THIS WILL CONTINUE TO OCCUR WITH SOME
SPORADIC GUSTS BUT WITH A SHIFT BACK TO THE EAST NORTHEAST BY MID
AFTERNOON...WITH WINDS REMAINING MORE NORTHERLY THROUGH THE END OF
THE FORECAST PERIOD. DO EXPECT AN INCREASE IN ACTIVITY BY MID
AFTERNOON WITH SCATTERED SHOWERS/THUNDERSTORMS EXPECTED TO DEVELOP
ACROSS THE TERMINALS. THIS INITIAL ONSET IS EXPECTED TO ONLY HAVE
LIMITED IMPACTS ON THE TERMINALS BUT WITH THIS TO QUICKLY CHANGE
AS WE GO INTO THE LATE AFTERNOON. THUNDERSTORM DEVELOPMENT WILL
INCREASE WITH COVERAGE/INTENSITY OF THESE STORMS ALSO INCREASING
AS THEY SHIFT EAST ACROSS THE TERMINALS. NOT ONLY WILL LOWER
VIS/CEILINGS IN HEAVY RAIN WILL BE POSSIBLE...BUT STRONG/SHIFTING
WINDS ARE DEFINITELY POSSIBLE WITH THE STRONGEST THUNDERSTORMS
LATER THIS AFTERNOON. THIS WILL HAVE TO BE ADDRESSED WITH LATER
AMENDMENTS ONCE THUNDERSTORM INITIATION OCCURS AND THE FULL
THREAT OF CHANGING WEATHER FOR THE TERMINALS IS KNOWN.
SHOWERS/ISOLATED THUNDER SHOULD DIMINISH LATE THIS EVENING THROUGH
OVERNIGHT...WITH DRIER CONDITIONS EXPECTED EARLY THURSDAY MORNING
AS WELL AS CEILINGS IMPROVING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN CHANCES FOR THUNDERSTORMS LATER
TODAY AND TONIGHT...BUT MEDIUM CONFIDENCE ON THE ONSET TIMING.
* MEDIUM TO HIGH CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL
WITH LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022...4 PM WEDNESDAY
TO 4 AM THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002...4 PM WEDNESDAY TO 4 AM
THURSDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 PM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
113 PM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
1042 AM CDT
...WIDESPREAD SEVERE WEATHER OUTBREAK ACROSS THE REGION EXPECTED
LATE THIS AFTERNOON AND EVENING INCLUDING TORNADIC POTENTIAL IN
NORTH CENTRAL IL LATE THIS AFTERNOON...
SEVERE WEATHER THREAT CONTINUES WITH OBSERVATIONAL TRENDS HINTING
MORE AT PRECISE EVOLUTION AND TIMING.
WHAT LEFTS OF OVERNIGHT DECAYING MCS IS MOVING FROM SOUTHEAST WI
OVER LAKE MI. VISIBLE SATELLITE AND REGIONAL RADAR MOSAIC
INDICATE SOME BRIEF SUPPRESSION BEHIND THIS WHILE THERE IS AN AXIS
EXTENDING SOUTHWARD ON RADAR OF LIKELY SOME MID-LEVEL CONVERGENCE.
THERE HAS NOT BEEN ANY DEVELOPMENT ALONG THIS THUS FAR BUT CANNOT
RULE OUT A FEW ELEVATED STORMS THROUGH 3 PM OR SO ACROSS FAR
NORTHERN AND NORTHEAST IL.
THE SURFACE LOW PRESSURE IS DEVELOPING NORTHEASTWARD INTO SOUTHWEST
AND CENTRAL IA AS OF 10 AM WITH A WARM FRONT EVOLVING EAST
NORTHEAST FROM THERE. THIS LOOKS TO BE FROM NEAR WATERLOO IA TO
SAVANNA IL AND THEN BECOMING MORE ILL-DEFINED EAST OF THERE INTO
THE CWA. DEW POINTS IN THE LOWER 70S ARE ADVECTING UP TO THIS
BOUNDARY WITH WINDS STRONGLY BACKED TO THE NORTH OF THIS. THERE
HAS BEEN GROWTH IN THE CU ACROSS IA NEAR THIS DEVELOPING FRONT.
AS THE MAIN VORT MAX AND MID-LEVEL SPEED MAX MOVE EAST FROM
EASTERN SD/NORTHEAST NE...DEVELOPMENT OF ROBUST CONVECTION IS
HIGHLY LIKELY BY MID AFTERNOON ACROSS NE IA/SW WI/NW IL. SUPERCELL
DEVELOPMENT WOULD BE A FAVORED MODE ALONG AND IMMEDIATELY NORTH OF
THE WARM FRONT. FURTHER NORTH AND NORTHEAST FROM THE TWIN CITIES
TO MILWAUKEE...ELEVATED CONVECTION MAY INCREASE. ALL OF THIS IS
SLIGHTLY FURTHER NORTH THAN EARLIER ANTICIPATED...BUT THE SEVERE
WEATHER THREAT HAS NOT DIMINISHED FOR OUR AREA...JUST FOCUSED MORE
SO IN THE LATE AFTERNOON AND EVE.
GIVEN THE ANTICIPATED EVOLUTION MENTIONED ABOVE WHICH HAS THE
SUPPORT OF THE RAP AND SEVERAL CONVECTIVE-ALLOWING MODELS...NORTH
CENTRAL IL WILL LIKELY BE UNDER THE GUN LATE THIS AFTERNOON. THIS
INCLUDES THE ROCKFORD AREA DURING RUSH HOUR AS STORMS EVOLVE
EASTWARD IN A FAVORED COMBINATION OF DISCRETE TO SMALL SCALE
CLUSTERS. TORNADIC POTENTIAL WILL CERTAINLY EXIST WITH THESE GIVEN
THE HELICITY RICH AIR NEAR THE BOUNDARY AND ANTICIPATED SURFACE-
BASED CAPE. CONVECTIVE TEMPERATURES FOR THIS ARE FORECAST TO BE
AROUND 80 DEGREES ON THE RAP. WHILE TEMPERATURE TRENDS HAVE BEEN
SLOW TO CLIMB ACROSS THE AREA THUS FAR...SOME THINNING OF THE
CLOUDS AND THE NORTHWARD PUSH OF THE WARM SECTOR SHOULD ALLOW THAT
TO OCCUR.
THE EVENING TIME PERIOD SHOULD SEE THE MOST COVERAGE OF SEVERE
CONVECTION IN THE FORECAST AREA AND WILL BE THE PRIME TIME FOR
CHICAGOLAND. THE LOW-LEVEL JET IS FORECAST TO INCREASE TO 40-50 KT
AND POINT INTO THE ONGOING CONVECTION. SOME SCATTERED CONVECTIVE
DEVELOPMENT...POTENTIALLY SEVERE AND SURFACE BASED...EAST AND
SOUTH OF THIS IS FAVORED DURING THE EVE. SUFFICIENT DEEP LAYER
SHEAR AND RICH LOW-LEVEL MOISTURE WILL OFFER AMPLE WIND THREAT
WITH THE ORGANIZED CONVECTIVE CLUSTERS. WITH THE SURFACE LOW
PROJECTED TO TRACK EAST NEAR THE I-88 CORRIDOR...THERE IS
INCREASING LIKELIHOOD THAT THE MAIN MCV/MCS WILL DEVELOP NEAR THIS
CORRIDOR AS WELL. A MAJORITY OF THE EXPLICIT GUIDANCE DOES
INDICATE THIS. VERY HEAVY RAINFALL AND AN ENHANCED WIND THREAT
WILL EXIST WITH THIS...WHICH WOULD LIKELY IMPACT CHICAGO IN THE
6-10 PM TIME FRAME.
MTF
&&
.DISCUSSION...
304 AM CDT
...MAJOR SEVERE WEATHER OUTBREAK LIKELY THIS AFTERNOON AND
EVENING...WITH HEAVY RAINFALL ALSO LIKELY...
EVERYTHING LINING UP FOR A SIGNIFICANT SEVERE WEATHER OUTBREAK
TODAY. SPC DAY 1 OUTLOOK HAS ENTIRE FORECAST AREA IN MODERATE RISK
OF SEVERE WITH SIGNIFICANT WIND...HAIL...AND TORNADO THREAT. AT THE
SURFACE...LOW PRESSURE OVER THE PLAINS WITH A WEAK WARM FRONT
EXTENDING EAST INTO NORTHERN IL EARLY THIS MORNING. THE LOW WILL
MOVE EAST ALONG THE IA/MO BOARDER TODAY...AND ACROSS NORTHERN IL
THIS EVENING. VERY MOIST LOW LEVEL AIR WITH SURFACE DEW POINTS IN
THE MID AND UPPER 60S IN PLACE. MAY SEE DEWPOINTS POOL IN THE LOWER
70S SOUTH OF WARM FRONT THIS AFTERNOON. THE BOUNDARY WILL INTENSIFY
AS SOUTHWEST LOW LEVEL FLOW INCREASES SOUTH OF THE FRONT AND SURFACE
WINDS BACK TO SE OR E NORTH OF THE BOUNDARY. THIS WILL PULL MODIFIED
MARINE AIR BACK ACROSS FAR NORTHERN IL. HAVE SOME CONCERNS ABOUT HOW
FAR NORTH THE WARM FRONT WILL TRAVEL. SPC DISCUSSION SUGGESTING THE
BOUNDARY WILL MOVE INTO SOUTHERN WI BUT WITH MODELS TAKING LOW
ACROSS I-80 CORRIDOR AND COOLING INFLUENCE OF LAKE
MICHIGAN...THINKING FRONT WONT GET MUCH FARTHER NORTH THAN A
DIXON-GARY LINE. THIS MAY LIMIT NORTHERN EXTEND OF SIGNIFICANT
SEVERE THREAT. THE BOUNDARY WILL ALSO RESULT IN A CHALLENGING
TEMPERATURE FORECAST...WITH TEMPS REACHING LOWER 90S FAR SOUTHERN
PART OF FORECAST AREA...WHILE AREAS ALONG THE NORTH SHORE WILL
LIKELY BE 20 DEGREES COOLER. IT APPEARS THAT MOST OF THE OVERNIGHT
EARLY MORNING CONVECTION WILL AFFECT WI...BUT KEEPING AN EYE ON
MCS OVER WESTERN IA WHICH COULD MOVE INTO NORTHERN IL THIS
MORNING. EARLIER CONVECTION OVER EASTERN IA WEAKENED AS IT MOVED
EAST AND THINK THIS MCS MAY DO THE SAME. CLOUD DEBRIS SHOULD
REMAIN NORTH ALLOWING AREAS SOUTH OF THE WARM FRONT TO HEAT UP
SIGNIFICANTLY...INTO THE UPPER 80S TO LOWER 90S. THIS COULD RESULT
IN SURFACE BASED CAPE OF 3000+ THIS AFTERNOON. FAIRLY VIGOROUS
SHORT WAVE MOVING INTO WESTERN SD/NE EARLY THIS MORNING WILL BE
MOVING ACROSS NORTHERN IL THIS EVENING. MODEL SOUNDINGS SHOW
FAIRLY STOUT CAP EARLY IN THE DAY ERODES THIS AFTERNOON WITH
APPROACHING SHORT WAVE. LOOKING AT 0-6KM BULK SHEAR 50-60 KTS BY
THIS EVENING. WITH INCREASING LOW LEVEL FLOW THIS AFTERNOON AND
BACKING SURFACE WINDS ALONG THE BOUNDARY...SHOULD PRODUCE AN
ENVIRONMENT FAVORABLE FOR DAMAGING WINDS...LARGE HAIL...AND
TORNADOES. SOME OF THE SHORT RANGE HI RES GUIDANCE IS SUGGESTING
DISCRETE STORMS INITIALLY THIS AFTERNOON. EXPECT THE TORNADO
THREAT TO BE MAINLY DURING THE AFTERNOON. STORMS WILL LIKELY
CONGEAL INTO AN MCS AND BECOME MORE OF A HIGH WIND WITH EMBEDDED
QLCS TORNADO THREAT IN THE EVENING. THE OTHER CONCERN IS WITH
PWATS AROUND 2 INCHES...AND SURFACE DEW POINTS NEAR
70...THUNDERSTORMS WILL BE CAPABLE OF VERY HEAVY RAINFALL AND AS
MCS DEVELOPS...FLOODING WILL ALSO BE A CONCERN. MODEL CONSENSUS IS
TO PLACE HEAVIEST QPF NORTH OF THE BOUNDARY OVER THE RFD AND
CHICAGO AREAS. SEE HYDRO SECTION OF THE AFD BELOW.
AFTER THE PASSAGE OF THIS SYSTEM...CENTRAL US RIDGE SHARPENS
BRINGING MUCH DRIER AND COOLER NORTHWEST FLOW FOR THU AND FRI.
EVENTUALLY PACNW UPPER LOW MOVES EAST ACROSS THE CANADIAN PRAIRIES
WHICH WILL PUSH THE RIDGE AXIS EASTWARD AND FLATTEN IT OUT. THUS A
FEW MORE ROUNDS OF THUNDERSTORMS ARE LIKELY TO RETURN SATURDAY AND
SUNDAY AND POSSIBLY INTO MONDAY BEFORE UPPER LOW OPENS INTO A
POTENT SHORT WAVE AND DROPS SOUTHEAST THROUGH THE GREAT LAKES.
ALLSOPP
&&
.HYDROLOGY...
HAVE ISSUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
DIXON TO VALPARAISO LINE. THERE IS THE POTENTIAL FOR WIDESPREAD HEAVY
RAINFALL OF 2 TO 3 INCHES ACROSS THIS AREA...WITH LOCALLY UP TO 5
INCHES. THE AXIS OF HEAVIEST RAIN WILL BE OVER THE HIGHLY
URBANIZED ROCKFORD AND CHICAGO METRO AREAS. ALSO CONCERNED FOR THE
POTENTIAL OF VERY HIGH RAINFALL RATES IN SOME OF THE HEAVIER DOWNPOURS.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* STRONG/SEVERE THUNDERSTORM POTENTIAL LATE THIS AFTERNOON INTO
THIS EVENING THAT COULD HAVE SIGNIFICANT IMPACTS ON THE
TERMINALS...SHOWERS/THUNDERSTORMS INCREASING AFTER 20Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR/LIFR VIS
AND IFR CIGS POSSIBLE FOR A PERIOD.
* SOUTHERLY WINDS WITH GUSTS IN THE MID/UPPER TEENS POSSIBLE
BEFORE WINDS ARE EXPECTED TO GO BACK TO THE EAST NORTHEAST BY
MID AFTERNOON...THEN INCREASING OUT OF THE NORTH/NORTHEAST THIS
EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
CONTINUE TO MONITOR THE POTENTIAL FOR SIGNIFICANT WEATHER TO AFFECT
THE TERMINALS LATER THIS AFTERNOON THROUGH THIS EVENING. ALTHOUGH
AT THIS TIME...RATHER QUIET ACROSS THE TERMINALS WITH VFR
CONDITIONS IN PLACE. WITH THE TRACK OF THE LOW THIS
MORNING...WINDS HAVE ACTUALLY BEEN ORIENTED MORE OUT OF A
SOUTHERLY DIRECTION TODAY. THIS WILL CONTINUE TO OCCUR WITH SOME
SPORADIC GUSTS BUT WITH A SHIFT BACK TO THE EAST NORTHEAST BY MID
AFTERNOON...WITH WINDS REMAINING MORE NORTHERLY THROUGH THE END OF
THE FORECAST PERIOD. DO EXPECT AN INCREASE IN ACTIVITY BY MID
AFTERNOON WITH SCATTERED SHOWERS/THUNDERSTORMS EXPECTED TO DEVELOP
ACROSS THE TERMINALS. THIS INITIAL ONSET IS EXPECTED TO ONLY HAVE
LIMITED IMPACTS ON THE TERMINALS BUT WITH THIS TO QUICKLY CHANGE
AS WE GO INTO THE LATE AFTERNOON. THUNDERSTORM DEVELOPMENT WILL
INCREASE WITH COVERAGE/INTENSITY OF THESE STORMS ALSO INCREASING
AS THEY SHIFT EAST ACROSS THE TERMINALS. NOT ONLY WILL LOWER
VIS/CEILINGS IN HEAVY RAIN WILL BE POSSIBLE...BUT STRONG/SHIFTING
WINDS ARE DEFINITELY POSSIBLE WITH THE STRONGEST THUNDERSTORMS
LATER THIS AFTERNOON. THIS WILL HAVE TO BE ADDRESSED WITH LATER
AMENDMENTS ONCE THUNDERSTORM INITIATION OCCURS AND THE FULL
THREAT OF CHANGING WEATHER FOR THE TERMINALS IS KNOWN.
SHOWERS/ISOLATED THUNDER SHOULD DIMINISH LATE THIS EVENING THROUGH
OVERNIGHT...WITH DRIER CONDITIONS EXPECTED EARLY THURSDAY MORNING
AS WELL AS CEILINGS IMPROVING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN CHANCES FOR THUNDERSTORMS LATER
TODAY AND TONIGHT...BUT MEDIUM CONFIDENCE ON THE ONSET TIMING.
* MEDIUM TO HIGH CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL
WITH LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022...4 PM WEDNESDAY
TO 4 AM THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002...4 PM WEDNESDAY TO 4 AM
THURSDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 PM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1121 AM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
1042 AM CDT
...WIDESPREAD SEVERE WEATHER OUTBREAK ACROSS THE REGION EXPECTED
LATE THIS AFTERNOON AND EVENING INCLUDING TORNADIC POTENTIAL IN
NORTH CENTRAL IL LATE THIS AFTERNOON...
SEVERE WEATHER THREAT CONTINUES WITH OBSERVATIONAL TRENDS HINTING
MORE AT PRECISE EVOLUTION AND TIMING.
WHAT LEFTS OF OVERNIGHT DECAYING MCS IS MOVING FROM SOUTHEAST WI
OVER LAKE MI. VISIBLE SATELLITE AND REGIONAL RADAR MOSAIC
INDICATE SOME BRIEF SUPPRESSION BEHIND THIS WHILE THERE IS AN AXIS
EXTENDING SOUTHWARD ON RADAR OF LIKELY SOME MID-LEVEL CONVERGENCE.
THERE HAS NOT BEEN ANY DEVELOPMENT ALONG THIS THUS FAR BUT CANNOT
RULE OUT A FEW ELEVATED STORMS THROUGH 3 PM OR SO ACROSS FAR
NORTHERN AND NORTHEAST IL.
THE SURFACE LOW PRESSURE IS DEVELOPING NORTHEASTWARD INTO SOUTHWEST
AND CENTRAL IA AS OF 10 AM WITH A WARM FRONT EVOLVING EAST
NORTHEAST FROM THERE. THIS LOOKS TO BE FROM NEAR WATERLOO IA TO
SAVANNA IL AND THEN BECOMING MORE ILL-DEFINED EAST OF THERE INTO
THE CWA. DEW POINTS IN THE LOWER 70S ARE ADVECTING UP TO THIS
BOUNDARY WITH WINDS STRONGLY BACKED TO THE NORTH OF THIS. THERE
HAS BEEN GROWTH IN THE CU ACROSS IA NEAR THIS DEVELOPING FRONT.
AS THE MAIN VORT MAX AND MID-LEVEL SPEED MAX MOVE EAST FROM
EASTERN SD/NORTHEAST NE...DEVELOPMENT OF ROBUST CONVECTION IS
HIGHLY LIKELY BY MID AFTERNOON ACROSS NE IA/SW WI/NW IL. SUPERCELL
DEVELOPMENT WOULD BE A FAVORED MODE ALONG AND IMMEDIATELY NORTH OF
THE WARM FRONT. FURTHER NORTH AND NORTHEAST FROM THE TWIN CITIES
TO MILWAUKEE...ELEVATED CONVECTION MAY INCREASE. ALL OF THIS IS
SLIGHTLY FURTHER NORTH THAN EARLIER ANTICIPATED...BUT THE SEVERE
WEATHER THREAT HAS NOT DIMINISHED FOR OUR AREA...JUST FOCUSED MORE
SO IN THE LATE AFTERNOON AND EVE.
GIVEN THE ANTICIPATED EVOLUTION MENTIONED ABOVE WHICH HAS THE
SUPPORT OF THE RAP AND SEVERAL CONVECTIVE-ALLOWING MODELS...NORTH
CENTRAL IL WILL LIKELY BE UNDER THE GUN LATE THIS AFTERNOON. THIS
INCLUDES THE ROCKFORD AREA DURING RUSH HOUR AS STORMS EVOLVE
EASTWARD IN A FAVORED COMBINATION OF DISCRETE TO SMALL SCALE
CLUSTERS. TORNADIC POTENTIAL WILL CERTAINLY EXIST WITH THESE GIVEN
THE HELICITY RICH AIR NEAR THE BOUNDARY AND ANTICIPATED SURFACE-
BASED CAPE. CONVECTIVE TEMPERATURES FOR THIS ARE FORECAST TO BE
AROUND 80 DEGREES ON THE RAP. WHILE TEMPERATURE TRENDS HAVE BEEN
SLOW TO CLIMB ACROSS THE AREA THUS FAR...SOME THINNING OF THE
CLOUDS AND THE NORTHWARD PUSH OF THE WARM SECTOR SHOULD ALLOW THAT
TO OCCUR.
THE EVENING TIME PERIOD SHOULD SEE THE MOST COVERAGE OF SEVERE
CONVECTION IN THE FORECAST AREA AND WILL BE THE PRIME TIME FOR
CHICAGOLAND. THE LOW-LEVEL JET IS FORECAST TO INCREASE TO 40-50 KT
AND POINT INTO THE ONGOING CONVECTION. SOME SCATTERED CONVECTIVE
DEVELOPMENT...POTENTIALLY SEVERE AND SURFACE BASED...EAST AND
SOUTH OF THIS IS FAVORED DURING THE EVE. SUFFICIENT DEEP LAYER
SHEAR AND RICH LOW-LEVEL MOISTURE WILL OFFER AMPLE WIND THREAT
WITH THE ORGANIZED CONVECTIVE CLUSTERS. WITH THE SURFACE LOW
PROJECTED TO TRACK EAST NEAR THE I-88 CORRIDOR...THERE IS
INCREASING LIKELIHOOD THAT THE MAIN MCV/MCS WILL DEVELOP NEAR THIS
CORRIDOR AS WELL. A MAJORITY OF THE EXPLICIT GUIDANCE DOES
INDICATE THIS. VERY HEAVY RAINFALL AND AN ENHANCED WIND THREAT
WILL EXIST WITH THIS...WHICH WOULD LIKELY IMPACT CHICAGO IN THE
6-10 PM TIME FRAME.
MTF
&&
.DISCUSSION...
304 AM CDT
...MAJOR SEVERE WEATHER OUTBREAK LIKELY THIS AFTERNOON AND
EVENING...WITH HEAVY RAINFALL ALSO LIKELY...
EVERYTHING LINING UP FOR A SIGNIFICANT SEVERE WEATHER OUTBREAK
TODAY. SPC DAY 1 OUTLOOK HAS ENTIRE FORECAST AREA IN MODERATE RISK
OF SEVERE WITH SIGNIFICANT WIND...HAIL...AND TORNADO THREAT. AT THE
SURFACE...LOW PRESSURE OVER THE PLAINS WITH A WEAK WARM FRONT
EXTENDING EAST INTO NORTHERN IL EARLY THIS MORNING. THE LOW WILL
MOVE EAST ALONG THE IA/MO BOARDER TODAY...AND ACROSS NORTHERN IL
THIS EVENING. VERY MOIST LOW LEVEL AIR WITH SURFACE DEW POINTS IN
THE MID AND UPPER 60S IN PLACE. MAY SEE DEWPOINTS POOL IN THE LOWER
70S SOUTH OF WARM FRONT THIS AFTERNOON. THE BOUNDARY WILL INTENSIFY
AS SOUTHWEST LOW LEVEL FLOW INCREASES SOUTH OF THE FRONT AND SURFACE
WINDS BACK TO SE OR E NORTH OF THE BOUNDARY. THIS WILL PULL MODIFIED
MARINE AIR BACK ACROSS FAR NORTHERN IL. HAVE SOME CONCERNS ABOUT HOW
FAR NORTH THE WARM FRONT WILL TRAVEL. SPC DISCUSSION SUGGESTING THE
BOUNDARY WILL MOVE INTO SOUTHERN WI BUT WITH MODELS TAKING LOW
ACROSS I-80 CORRIDOR AND COOLING INFLUENCE OF LAKE
MICHIGAN...THINKING FRONT WONT GET MUCH FARTHER NORTH THAN A
DIXON-GARY LINE. THIS MAY LIMIT NORTHERN EXTEND OF SIGNIFICANT
SEVERE THREAT. THE BOUNDARY WILL ALSO RESULT IN A CHALLENGING
TEMPERATURE FORECAST...WITH TEMPS REACHING LOWER 90S FAR SOUTHERN
PART OF FORECAST AREA...WHILE AREAS ALONG THE NORTH SHORE WILL
LIKELY BE 20 DEGREES COOLER. IT APPEARS THAT MOST OF THE OVERNIGHT
EARLY MORNING CONVECTION WILL AFFECT WI...BUT KEEPING AN EYE ON
MCS OVER WESTERN IA WHICH COULD MOVE INTO NORTHERN IL THIS
MORNING. EARLIER CONVECTION OVER EASTERN IA WEAKENED AS IT MOVED
EAST AND THINK THIS MCS MAY DO THE SAME. CLOUD DEBRIS SHOULD
REMAIN NORTH ALLOWING AREAS SOUTH OF THE WARM FRONT TO HEAT UP
SIGNIFICANTLY...INTO THE UPPER 80S TO LOWER 90S. THIS COULD RESULT
IN SURFACE BASED CAPE OF 3000+ THIS AFTERNOON. FAIRLY VIGOROUS
SHORT WAVE MOVING INTO WESTERN SD/NE EARLY THIS MORNING WILL BE
MOVING ACROSS NORTHERN IL THIS EVENING. MODEL SOUNDINGS SHOW
FAIRLY STOUT CAP EARLY IN THE DAY ERODES THIS AFTERNOON WITH
APPROACHING SHORT WAVE. LOOKING AT 0-6KM BULK SHEAR 50-60 KTS BY
THIS EVENING. WITH INCREASING LOW LEVEL FLOW THIS AFTERNOON AND
BACKING SURFACE WINDS ALONG THE BOUNDARY...SHOULD PRODUCE AN
ENVIRONMENT FAVORABLE FOR DAMAGING WINDS...LARGE HAIL...AND
TORNADOES. SOME OF THE SHORT RANGE HI RES GUIDANCE IS SUGGESTING
DISCRETE STORMS INITIALLY THIS AFTERNOON. EXPECT THE TORNADO
THREAT TO BE MAINLY DURING THE AFTERNOON. STORMS WILL LIKELY
CONGEAL INTO AN MCS AND BECOME MORE OF A HIGH WIND WITH EMBEDDED
QLCS TORNADO THREAT IN THE EVENING. THE OTHER CONCERN IS WITH
PWATS AROUND 2 INCHES...AND SURFACE DEW POINTS NEAR
70...THUNDERSTORMS WILL BE CAPABLE OF VERY HEAVY RAINFALL AND AS
MCS DEVELOPS...FLOODING WILL ALSO BE A CONCERN. MODEL CONSENSUS IS
TO PLACE HEAVIEST QPF NORTH OF THE BOUNDARY OVER THE RFD AND
CHICAGO AREAS. SEE HYDRO SECTION OF THE AFD BELOW.
AFTER THE PASSAGE OF THIS SYSTEM...CENTRAL US RIDGE SHARPENS
BRINGING MUCH DRIER AND COOLER NORTHWEST FLOW FOR THU AND FRI.
EVENTUALLY PACNW UPPER LOW MOVES EAST ACROSS THE CANADIAN PRAIRIES
WHICH WILL PUSH THE RIDGE AXIS EASTWARD AND FLATTEN IT OUT. THUS A
FEW MORE ROUNDS OF THUNDERSTORMS ARE LIKELY TO RETURN SATURDAY AND
SUNDAY AND POSSIBLY INTO MONDAY BEFORE UPPER LOW OPENS INTO A
POTENT SHORT WAVE AND DROPS SOUTHEAST THROUGH THE GREAT LAKES.
ALLSOPP
&&
.HYDROLOGY...
HAVE ISSUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
DIXON TO VALPARAISO LINE. THERE IS THE POTENTIAL FOR WIDESPREAD HEAVY
RAINFALL OF 2 TO 3 INCHES ACROSS THIS AREA...WITH LOCALLY UP TO 5
INCHES. THE AXIS OF HEAVIEST RAIN WILL BE OVER THE HIGHLY
URBANIZED ROCKFORD AND CHICAGO METRO AREAS. ALSO CONCERNED FOR THE
POTENTIAL OF VERY HIGH RAINFALL RATES IN SOME OF THE HEAVIER DOWNPOURS.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* STRONG TO SEVERE THUNDERSTORM POTENTIAL LATER TODAY AND INTO
THIS EVENING...WITH SHOWERS/THUNDERSTORMS INCREASING AFTER
19-20Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR VIS AND
CIGS POSSIBLE FOR A PERIOD.
* SOUTH TO SOUTHWEST WIND NOW LIKELY WITH GUSTS TO AROUND 19KT
THROUGH EARLY AFTERNOON...BEFORE GOING BACK TO THE EAST
NORTHEAST BY MID AFTERNOON.
RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
FORECAST CHALLENGES THIS MORNING CONTINUE TO CENTER AROUND TIMING
THE ONSET OF THUNDERSTORM ACTIVITY TODAY.
A COMPLEX OF THUNDERSTORMS ACROSS IOWA DEVELOPED EARLIER THIS
MORNING ALONG THE NOSE OF A LOW LEVEL JET. THIS ACTIVITY HAS BEEN
WEAKENING OVER THE PAST COUPLE HOURS. HOWEVER...THIS ACTIVITY HAS
ENHANCED A MID LEVEL DISTURBANCE (MCV) ACROSS NORTHERN IOWA. THIS
LEAD DISTURBANCE COULD ACT TO SPARK OFF SOME SCT CONVECTION ACROSS
FAR NORTHERN ILLINOIS LATER THIS MORNING. CONFIDENCE IS LOW WITH
THE POTENTIAL FOR THIS EARLIER ACTIVITY. HOWEVER...I FELT THAT A
VCSH MENTION WAS JUSTIFIED AFTER 15 UTC.
OTHERWISE...THE ONLY OTHER CHANCES TO NEW TAFS WAS TO ADD A VCTS
AFTER 20 UTC...A COUPLE HOURS EARLIER THAN THE PREVIOUS 22 UTC
TIMING. THIS WAS MAINLY DUE TO THE POTENTIAL FOR ACTIVITY TO FIRE
ALONG THE SURFACE FRONT. IT APPEARS THAT AS THE SURFACE FLOW
INCREASES OFF THE LAKE TO THE NORTH OF THE WARM FRONTAL BOUNDARY
THAT LOW LEVEL CONVERGENCE WILL STRENGTHEN...AND THIS COULD BE
ENOUGH TO FIRE OFF ACTIVITY BY EARLY TO MID AFTERNOON.
BY FAR THE BEST CHANCES FOR THUNDERSTORMS WILL BE LATER THIS
AFTERNOON AND EVENING. THIS IS THE TIME WHEN THE BEST DYNAMICS
ASSOCIATED WITH THE MAIN DISTURBANCE SHOULD OVERSPREAD THE AREA.
SEVERE THUNDERSTORMS WITH LARGE HAIL...DAMAGING WINDS...AND EVEN
TORNADO`S ARE STILL POSSIBLE. VERY HEAVY RAINFALL WILL ALSO LIKELY
ACCOMPANY THESE STORMS...ESPECIALLY THIS EVENING. THIS COULD LEAD
TO LOCALIZED FLOODING AND REDUCTIONS IN THE VIS DOWN UNDER 2
MILES. IT APPEARS THAT THIS ACTIVITY COULD LAST FOR A 3 TO 6 HOUR
WINDOW INTO THIS EVENING BEFORE CONDITIONS BEGIN TO IMPROVE
OVERNIGHT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM TO HIGH CONFIDENCE IN CHANCES FOR THUNDERSTORMS LATER
TODAY AND TONIGHT...BUT LOW MEDIUM CONFIDENCE ON THE ONSET
TIMING.
* MEDIUM CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL WITH
LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022...4 PM WEDNESDAY
TO 4 AM THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002...4 PM WEDNESDAY TO 4 AM
THURSDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 PM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1043 AM CDT WED JUN 12 2013
.MESOSCALE DISCUSSION...
1042 AM CDT
...WIDESPREAD SEVERE WEATHER OUTBREAK ACROSS THE REGION EXPECTED
LATE THIS AFTERNOON AND EVENING INCLUDING TORNADIC POTENTIAL IN
NORTH CENTRAL IL LATE THIS AFTERNOON...
SEVERE WEATHER THREAT CONTINUES WITH OBSERVATIONAL TRENDS HINTING
MORE AT PRECISE EVOLUTION AND TIMING.
WHAT LEFTS OF OVERNIGHT DECAYING MCS IS MOVING FROM SOUTHEAST WI
OVER LAKE MI. VISIBLE SATELLITE AND REGIONAL RADAR MOSAIC
INDICATE SOME BRIEF SUPPRESSION BEHIND THIS WHILE THERE IS AN AXIS
EXTENDING SOUTHWARD ON RADAR OF LIKELY SOME MID-LEVEL CONVERGENCE.
THERE HAS NOT BEEN ANY DEVELOPMENT ALONG THIS THUS FAR BUT CANNOT
RULE OUT A FEW ELEVATED STORMS THROUGH 3 PM OR SO ACROSS FAR
NORTHERN AND NORTHEAST IL.
THE SURFACE LOW PRESSURE IS DEVELOPING NORTHEASTWARD INTO SOUTHWEST
AND CENTRAL IA AS OF 10 AM WITH A WARM FRONT EVOLVING EAST
NORTHEAST FROM THERE. THIS LOOKS TO BE FROM NEAR WATERLOO IA TO
SAVANNA IL AND THEN BECOMING MORE ILL-DEFINED EAST OF THERE INTO
THE CWA. DEW POINTS IN THE LOWER 70S ARE ADVECTING UP TO THIS
BOUNDARY WITH WINDS STRONGLY BACKED TO THE NORTH OF THIS. THERE
HAS BEEN GROWTH IN THE CU ACROSS IA NEAR THIS DEVELOPING FRONT.
AS THE MAIN VORT MAX AND MID-LEVEL SPEED MAX MOVE EAST FROM
EASTERN SD/NORTHEAST NE...DEVELOPMENT OF ROBUST CONVECTION IS
HIGHLY LIKELY BY MID AFTERNOON ACROSS NE IA/SW WI/NW IL. SUPERCELL
DEVELOPMENT WOULD BE A FAVORED MODE ALONG AND IMMEDIATELY NORTH OF
THE WARM FRONT. FURTHER NORTH AND NORTHEAST FROM THE TWIN CITIES
TO MILWAUKEE...ELEVATED CONVECTION MAY INCREASE. ALL OF THIS IS
SLIGHTLY FURTHER NORTH THAN EARLIER ANTICIPATED...BUT THE SEVERE
WEATHER THREAT HAS NOT DIMINISHED FOR OUR AREA...JUST FOCUSED MORE
SO IN THE LATE AFTERNOON AND EVE.
GIVEN THE ANTICIPATED EVOLUTION MENTIONED ABOVE WHICH HAS THE
SUPPORT OF THE RAP AND SEVERAL CONVECTIVE-ALLOWING MODELS...NORTH
CENTRAL IL WILL LIKELY BE UNDER THE GUN LATE THIS AFTERNOON. THIS
INCLUDES THE ROCKFORD AREA DURING RUSH HOUR AS STORMS EVOLVE
EASTWARD IN A FAVORED COMBINATION OF DISCRETE TO SMALL SCALE
CLUSTERS. TORNADIC POTENTIAL WILL CERTAINLY EXIST WITH THESE GIVEN
THE HELICITY RICH AIR NEAR THE BOUNDARY AND ANTICIPATED SURFACE-
BASED CAPE. CONVECTIVE TEMPERATURES FOR THIS ARE FORECAST TO BE
AROUND 80 DEGREES ON THE RAP. WHILE TEMPERATURE TRENDS HAVE BEEN
SLOW TO CLIMB ACROSS THE AREA THUS FAR...SOME THINNING OF THE
CLOUDS AND THE NORTHWARD PUSH OF THE WARM SECTOR SHOULD ALLOW THAT
TO OCCUR.
THE EVENING TIME PERIOD SHOULD SEE THE MOST COVERAGE OF SEVERE
CONVECTION IN THE FORECAST AREA AND WILL BE THE PRIME TIME FOR
CHICAGOLAND. THE LOW-LEVEL JET IS FORECAST TO INCREASE TO 40-50 KT
AND POINT INTO THE ONGOING CONVECTION. SOME SCATTERED CONVECTIVE
DEVELOPMENT...POTENTIALLY SEVERE AND SURFACE BASED...EAST AND
SOUTH OF THIS IS FAVORED DURING THE EVE. SUFFICIENT DEEP LAYER
SHEAR AND RICH LOW-LEVEL MOISTURE WILL OFFER AMPLE WIND THREAT
WITH THE ORGANIZED CONVECTIVE CLUSTERS. WITH THE SURFACE LOW
PROJECTED TO TRACK EAST NEAR THE I-88 CORRIDOR...THERE IS
INCREASING LIKELIHOOD THAT THE MAIN MCV/MCS WILL DEVELOP NEAR THIS
CORRIDOR AS WELL. A MAJORITY OF THE EXPLICIT GUIDANCE DOES
INDICATE THIS. VERY HEAVY RAINFALL AND AN ENHANCED WIND THREAT
WILL EXIST WITH THIS...WHICH WOULD LIKELY IMPACT CHICAGO IN THE
6-10 PM TIME FRAME.
MTF
&&
.DISCUSSION...
304 AM CDT
...MAJOR SEVERE WEATHER OUTBREAK LIKELY THIS AFTERNOON AND
EVENING...WITH HEAVY RAINFALL ALSO LIKELY...
EVERYTHING LINING UP FOR A SIGNIFICANT SEVERE WEATHER OUTBREAK
TODAY. SPC DAY 1 OUTLOOK HAS ENTIRE FORECAST AREA IN MODERATE RISK
OF SEVERE WITH SIGNIFICANT WIND...HAIL...AND TORNADO THREAT. AT THE
SURFACE...LOW PRESSURE OVER THE PLAINS WITH A WEAK WARM FRONT
EXTENDING EAST INTO NORTHERN IL EARLY THIS MORNING. THE LOW WILL
MOVE EAST ALONG THE IA/MO BOARDER TODAY...AND ACROSS NORTHERN IL
THIS EVENING. VERY MOIST LOW LEVEL AIR WITH SURFACE DEW POINTS IN
THE MID AND UPPER 60S IN PLACE. MAY SEE DEWPOINTS POOL IN THE LOWER
70S SOUTH OF WARM FRONT THIS AFTERNOON. THE BOUNDARY WILL INTENSIFY
AS SOUTHWEST LOW LEVEL FLOW INCREASES SOUTH OF THE FRONT AND SURFACE
WINDS BACK TO SE OR E NORTH OF THE BOUNDARY. THIS WILL PULL MODIFIED
MARINE AIR BACK ACROSS FAR NORTHERN IL. HAVE SOME CONCERNS ABOUT HOW
FAR NORTH THE WARM FRONT WILL TRAVEL. SPC DISCUSSION SUGGESTING THE
BOUNDARY WILL MOVE INTO SOUTHERN WI BUT WITH MODELS TAKING LOW
ACROSS I-80 CORRIDOR AND COOLING INFLUENCE OF LAKE
MICHIGAN...THINKING FRONT WONT GET MUCH FARTHER NORTH THAN A
DIXON-GARY LINE. THIS MAY LIMIT NORTHERN EXTEND OF SIGNIFICANT
SEVERE THREAT. THE BOUNDARY WILL ALSO RESULT IN A CHALLENGING
TEMPERATURE FORECAST...WITH TEMPS REACHING LOWER 90S FAR SOUTHERN
PART OF FORECAST AREA...WHILE AREAS ALONG THE NORTH SHORE WILL
LIKELY BE 20 DEGREES COOLER. IT APPEARS THAT MOST OF THE OVERNIGHT
EARLY MORNING CONVECTION WILL AFFECT WI...BUT KEEPING AN EYE ON
MCS OVER WESTERN IA WHICH COULD MOVE INTO NORTHERN IL THIS
MORNING. EARLIER CONVECTION OVER EASTERN IA WEAKENED AS IT MOVED
EAST AND THINK THIS MCS MAY DO THE SAME. CLOUD DEBRIS SHOULD
REMAIN NORTH ALLOWING AREAS SOUTH OF THE WARM FRONT TO HEAT UP
SIGNIFICANTLY...INTO THE UPPER 80S TO LOWER 90S. THIS COULD RESULT
IN SURFACE BASED CAPE OF 3000+ THIS AFTERNOON. FAIRLY VIGOROUS
SHORT WAVE MOVING INTO WESTERN SD/NE EARLY THIS MORNING WILL BE
MOVING ACROSS NORTHERN IL THIS EVENING. MODEL SOUNDINGS SHOW
FAIRLY STOUT CAP EARLY IN THE DAY ERODES THIS AFTERNOON WITH
APPROACHING SHORT WAVE. LOOKING AT 0-6KM BULK SHEAR 50-60 KTS BY
THIS EVENING. WITH INCREASING LOW LEVEL FLOW THIS AFTERNOON AND
BACKING SURFACE WINDS ALONG THE BOUNDARY...SHOULD PRODUCE AN
ENVIRONMENT FAVORABLE FOR DAMAGING WINDS...LARGE HAIL...AND
TORNADOES. SOME OF THE SHORT RANGE HI RES GUIDANCE IS SUGGESTING
DISCRETE STORMS INITIALLY THIS AFTERNOON. EXPECT THE TORNADO
THREAT TO BE MAINLY DURING THE AFTERNOON. STORMS WILL LIKELY
CONGEAL INTO AN MCS AND BECOME MORE OF A HIGH WIND WITH EMBEDDED
QLCS TORNADO THREAT IN THE EVENING. THE OTHER CONCERN IS WITH
PWATS AROUND 2 INCHES...AND SURFACE DEW POINTS NEAR
70...THUNDERSTORMS WILL BE CAPABLE OF VERY HEAVY RAINFALL AND AS
MCS DEVELOPS...FLOODING WILL ALSO BE A CONCERN. MODEL CONSENSUS IS
TO PLACE HEAVIEST QPF NORTH OF THE BOUNDARY OVER THE RFD AND
CHICAGO AREAS. SEE HYDRO SECTION OF THE AFD BELOW.
AFTER THE PASSAGE OF THIS SYSTEM...CENTRAL US RIDGE SHARPENS
BRINGING MUCH DRIER AND COOLER NORTHWEST FLOW FOR THU AND FRI.
EVENTUALLY PACNW UPPER LOW MOVES EAST ACROSS THE CANADIAN PRAIRIES
WHICH WILL PUSH THE RIDGE AXIS EASTWARD AND FLATTEN IT OUT. THUS A
FEW MORE ROUNDS OF THUNDERSTORMS ARE LIKELY TO RETURN SATURDAY AND
SUNDAY AND POSSIBLY INTO MONDAY BEFORE UPPER LOW OPENS INTO A
POTENT SHORT WAVE AND DROPS SOUTHEAST THROUGH THE GREAT LAKES.
ALLSOPP
&&
.HYDROLOGY...304 AM CDT
HAVE ISSUED A FLASH FLOOD WATCH FOR AREAS GENERALLY NORTH OF A
DIXON TO VALPARAISO LINE. THERE IS THE POTENTIAL FOR WIDESPREAD HEAVY
RAINFALL OF 2 TO 3 INCHES ACROSS THIS AREA...WITH LOCALLY UP TO 5
INCHES. THE AXIS OF HEAVIEST RAIN WILL BE OVER THE HIGHLY
URBANIZED ROCKFORD AND CHICAGO METRO AREAS. ALSO CONCERNED FOR THE
POTENTIAL OF VERY HIGH RAINFALL RATES IN SOME OF THE HEAVIER DOWNPOURS.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* STRONG TO SEVERE THUNDERSTORM POTENTIAL LATER TODAY AND INTO
THIS EVENING...WITH SHOWERS/THUNDERSTORMS INCREASING AFTER 18Z.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR VIS AND
CIGS POSSIBLE FOR A PERIOD.
* VARIABLE WINDS FROM ORD TO MDW POSSIBLE...WITH A GENERAL
SOUTHEAST DIRECTION EXPECTED FOR BOTH TERMINALS THROUGH MID DAY.
THEN EXPECT MDW TO REMAIN SOUTHEAST WHILE ORD GOES NORTHEAST BY
18-19Z.
RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
FORECAST CHALLENGES THIS MORNING CONTINUE TO CENTER AROUND TIMING
THE ONSET OF THUNDERSTORM ACTIVITY TODAY.
A COMPLEX OF THUNDERSTORMS ACROSS IOWA DEVELOPED EARLIER THIS
MORNING ALONG THE NOSE OF A LOW LEVEL JET. THIS ACTIVITY HAS BEEN
WEAKENING OVER THE PAST COUPLE HOURS. HOWEVER...THIS ACTIVITY HAS
ENHANCED A MID LEVEL DISTURBANCE (MCV) ACROSS NORTHERN IOWA. THIS
LEAD DISTURBANCE COULD ACT TO SPARK OFF SOME SCT CONVECTION ACROSS
FAR NORTHERN ILLINOIS LATER THIS MORNING. CONFIDENCE IS LOW WITH
THE POTENTIAL FOR THIS EARLIER ACTIVITY. HOWEVER...I FELT THAT A
VCSH MENTION WAS JUSTIFIED AFTER 15 UTC.
OTHERWISE...THE ONLY OTHER CHANCES TO NEW TAFS WAS TO ADD A VCTS
AFTER 20 UTC...A COUPLE HOURS EARLIER THAN THE PREVIOUS 22 UTC
TIMING. THIS WAS MAINLY DUE TO THE POTENTIAL FOR ACTIVITY TO FIRE
ALONG THE SURFACE FRONT. IT APPEARS THAT AS THE SURFACE FLOW
INCREASES OFF THE LAKE TO THE NORTH OF THE WARM FRONTAL BOUNDARY
THAT LOW LEVEL CONVERGENCE WILL STRENGTHEN...AND THIS COULD BE
ENOUGH TO FIRE OFF ACTIVITY BY EARLY TO MID AFTERNOON.
BY FAR THE BEST CHANCES FOR THUNDERSTORMS WILL BE LATER THIS
AFTERNOON AND EVENING. THIS IS THE TIME WHEN THE BEST DYNAMICS
ASSOCIATED WITH THE MAIN DISTURBANCE SHOULD OVERSPREAD THE AREA.
SEVERE THUNDERSTORMS WITH LARGE HAIL...DAMAGING WINDS...AND EVEN
TORNADO`S ARE STILL POSSIBLE. VERY HEAVY RAINFALL WILL ALSO LIKELY
ACCOMPANY THESE STORMS...ESPECIALLY THIS EVENING. THIS COULD LEAD
TO LOCALIZED FLOODING AND REDUCTIONS IN THE VIS DOWN UNDER 2
MILES. IT APPEARS THAT THIS ACTIVITY COULD LAST FOR A 3 TO 6 HOUR
WINDOW INTO THIS EVENING BEFORE CONDITIONS BEGIN TO IMPROVE
OVERNIGHT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM TO HIGH CONFIDENCE IN CHANCES FOR THUNDERSTORMS LATER
TODAY AND TONIGHT...BUT LOW MEDIUM CONFIDENCE ON THE ONSET
TIMING.
* MODERATE CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL WITH
LOWER VIS AND CIGS THIS EVENING.
* MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TUESDAY...VFR.
KJB
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ020-ILZ022...4 PM WEDNESDAY TO 4 AM
THURSDAY.
IN...FLASH FLOOD WATCH...INZ001-INZ002...4 PM WEDNESDAY TO 4 AM
THURSDAY.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM THURSDAY TO 4
PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...4 AM THURSDAY TO
11 PM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
229 AM CDT WED JUN 12 2013
.DISCUSSION...
834 PM CDT
A FEW THOUGHTS REGARDING THE THUNDERSTORM THREAT OVERNIGHT AND THE
MODERATE RISK FOR SEVERE WEATHER WEDNESDAY...
THIS EVENING...A WARM FRONT EXTENDS FROM WESTERN IOWA EAST TOWARDS
IOWA CITY...THEN LOSES ITS DEFINITION SOUTHEAST INTO CENTRAL
ILLINOIS. LOW TO MID 70 DEW POINTS ARE POOLING ALONG THE BOUNDARY
TO OUR WEST...BUT AS A 20Z SOUNDING OUT OF DVN SHOWED...A STRONG
CAP IS IN PLACE WITH 825MB TEMPS AROUND 21C. LATEST RAP GUIDANCE
INDICATES THE THE CAP WILL REMAIN IN PLACE THROUGH THE REMAINDER
OF THE EVENING AND TONIGHT. WITH THAT SAID....THE THREAT FOR
SEVERE WEATHER THROUGH THE REMAINDER OF TODAY HAS GREATLY
DIMINISHED. FOCUS TURNS OUT TO THE WEST TONIGHT WHERE A 50-60KT
LOW LEVEL JET IS EXPECTED TO DEVELOP WITH THE BEST MOISTURE
CONVERGENCE FOCUSED OVER CENTRAL NEBRASKA...AND BY MIDNIGHT
TONIGHT SLIGHTLY FARTHER EAST OVER THE MID MISSOURI VALLEY.
DESPITE THE FOCUS BEING WELL OFF TO OUR WEST...THERE IS SOME
ASCENT ALONG THE WARM FRONT SO CAN NOT RULE OUT SOMETHING TRYING
TO DEVELOP THIS EVENING NORTH OF THE WARM FRONT AND MOVING INTO
NORTHERN ILLINOIS...BUT EXPECT COVERAGE TO BE LOW AWAY FROM THE
BETTER FORCING WITH THE LLJ. WITH THAT IN MIND...LOWERED POPS
ACROSS MUCH OF THE CWA FOR THE OVERNIGHT HOURS AND FEEL THEY MAY
STILL BE ON THE HIGH END. CONVECTIVE ALLOWING MODELS STILL SHOW
AN MCS DEVELOPING AT THE NOSE OF THE LLJ TONIGHT...AND BY
DAYBREAK TOMORROW POSSIBLY MOVING INTO NORTHWESTERN ILLINOIS...
BUT MORE LIKELY STAYING NORTH OF THE STATE LINE. EITHER WAY...LLJ
IS VEERING AND WEAKENING BY THAT TIME SO CONVECTION SHOULD BE IN
A WEAKENING PHASE.
THE STORM PREDICTION CENTER CONTINUES TO CARRY US UNDER A MODERATE
RISK WEDNESDAY AND THIS SEEMS TO BE ON TRACK. APPEARS WE WILL BE
UNDER A PRETTY DYNAMIC ENVIRONMENT TOMORROW AS A COUPLED JET SETS
UP WITH THE BEST UPPER LEVEL DIVERGENCE OVER CENTRAL AND NORTHERN
ILLINOIS. MODERATE HEIGHT FALLS ASSOCIATED WITH THE MID LEVEL WAVE
MOVING INTO THE AREA LATE AFTERNOON/EARLY EVENING TOMORROW WILL
PROVIDE LARGE SCALE ASCENT ACROSS THE AREA TO HELP WEAKEN THE CAP.
THE SURFACE LOW TRACKS EAST ACROSS THE MISSISSIPPI VALLEY JUST
SOUTH OF MLI...THOUGH THERE ARE SOME MODELS SUGGESTING THE LOW
TRACK AND RESULTING SEVERE THREAT MAY TRACK SLIGHTLY FARTHER
NORTH. SOME MODELS ALSO INDICATE THE LOW DEEPENING SLIGHTLY
TOMORROW AFTERNOON WITH 2-4MB PRESSURE FALLS OVERSPREADING AREAS
SOUTH OF I-80. THIS WILL ONLY HELP TO ENHANCE WHAT ALREADY LOOKS
TO BE PRETTY STRONG LOW LEVEL HELICITY TOMORROW. DEEP LAYER SHEAR
TOMORROW IS ALSO FORECAST TO BE QUITE STRONG. ALL SAID THERE IS
CONCERN FOR DISCRETE SUPER CELLS DEVELOPING IN THE AFTERNOON WITH
THE WHOLE GAMUT OF SEVERE WEATHER POSSIBLE...LARGE HAIL...
DAMAGING WINDS AND QUITE POSSIBLY TORNADOES. STORMS SHOULD
EVENTUALLY CONGEAL INTO A LINE WITH THE MAIN THREAT TURNING
BECOMING DAMAGING WINDS...THOUGH QLCS TORNADOES WILL STILL BE A
CONCERN. HOW QUICKLY WE TRANSITION FROM DISCRETE SUPER CELLS TO A
LINEAR MCS IS UNCERTAIN. INTERESTING TO NOTE THAT ONE OF THE TOP
CIPS ANALOGS IS JUNE 05 2010 WHICH DID HAVE DISCRETE SUPER CELLS
WITH TORNADOES LATER INTO THE EVENING.
DEUBELBEISS
//PREV DISCUSSION...
300 PM CDT
MAIN FORECAST CONCERNS/CHALLENGES IN THE NEAR TERM ARE WITH
MULTIPLE ROUNDS OF CONVECTION POSSIBLE ACROSS THE ENTIRE CWA
TONIGHT THROUGH WEDNESDAY NIGHT WITH SEVERE WEATHER NOT OUT OF
THE QUESTION THIS EVENING AND OVERNIGHT...BUT WITH A MORE
SIGNIFICANT SEVERE WEATHER OUTBREAK BECOMING INCREASINGLY MORE
POSSIBLE ACROSS A PORTION OF THE CWA ON WEDNESDAY.
IN THE NEAR TERM...CONTINUE TO MONITOR CONVECTION DEVELOPING JUST
SOUTHWEST/SOUTH OF THE CWA AT THIS TIME AS A MID LEVEL IMPULSE
SLIDES EAST ACROSS THE AREA AND ENCOUNTERS SOME WEAK LOW/MID
LEVEL CONVERGENCE IN AND AROUND SHIFTING SURFACE TROUGH ACROSS
IOWA. THIS AREA OF CONVECTION SHOULD CONTINUE EAST/SOUTHEAST WITH
TIME FOR THE REMAINDER OF THE AFTERNOON MAINLY ONLY AFFECTING
AREAS FROM LA SALLE IN ILLINOIS SOUTHEAST TO RENSSELAER IN
INDIANA...SUPPORTED BY THIS WAVE AND CURRENT WAA IN PLACE.
ALTHOUGH INSTABILITY REMAINS RATHER WEAK ACROSS THESE AREAS AS
WELL AS CIN IN PLACE...LATEST TRENDS SUPPORT A NORTHEASTWARD
EXPANSION OF THE INSTABILITY AXIS AS WELL AS WEAKENING CIN.
DESPITE WEAKLY FORCED...THESE CONDITIONS COINCIDING WITH
SUFFICIENT BULK SHEAR COULD SUPPORT AN ISOLATED HAIL/WIND THREAT
THROUGH LATE AFTERNOON. GOING INTO THE EARLY EVENING...COULD SEE
A DRY PERIOD FOR MOST OF NORTHERN ILLINOIS AND NORTHWEST INDIANA
BUT WITH THE POSSIBILITY FOR AN INCREASE IN COVERAGE OF
THUNDERSTORMS ONCE AGAIN LATER IN THE EVENING. THIS IS A DEFINITE
POSSIBILITY ESPECIALLY AS SEVERAL MID LEVEL FEATURES/SPEED MAXES
ARE ANTICIPATED TO ROUND THE MID LEVEL RIDGE...AS WELL AS A
VEERING LLJ STRENGTHENS THIS EVENING.
CONTINUE TO MONITOR THESE MID LEVEL FEATURES TRACKING EAST ACROSS
THE CENTRAL AND NORTHERN PLAINS ON LATEST VISIBLE
SATELLITE...TRYING TO GRAB A HANDLE ON THIS POSSIBILITY OF
INCREASED CHANCES FOR CONVECTION LATER THIS EVENING. THIS IS DUE
TO MOST GUIDANCE VARYING TO SOME DEGREE ON PLACEMENT AS WELL AS
TIMING THIS EVENING...WITH CONFIDENCE NOT THE GREATEST FOR
CONVECTIVE EVOLUTION THIS EVENING. ALTHOUGH LATEST THOUGHTS FOR
THIS EVENING ONCE AGAIN DO INCLUDE THE POSSIBILITY FOR AN
INCREASED CHANCE FOR THUNDERSTORMS AS WELL AS THE POSSIBILITY FOR
SEVERE WEATHER...DAMAGING WINDS AND HAIL ONCE AGAIN THE MAIN
THREATS. MID LEVEL FEATURE MOVING OUT OF THE CENTRAL PLAINS
SHOULD ENCOUNTER STRONG LOW/MID LEVEL CONVERGENCE IN IOWA...AND
SHOULD THEN SEE AN UP-GROWTH IN CONVECTION ACROSS EASTERN IOWA
JUST AFTER THE 7PM TIME FRAME. LATEST GUIDANCE IS SHOWING THAT
THE CURRENT NORTHEASTWARD EXPANSION OF THIS INSTABILITY AXIS WILL
CONTINUE THIS EVENING AND ORIENT ITSELF ACROSS NORTH CENTRAL/EAST
CENTRAL ILLINOIS. THIS INCREASED INSTABILITY AS WELL AS
SUFFICIENT 0-3/0-6KM BULK SHEAR THIS EVENING LENDS ITSELF TO
SUPPORT A POSSIBLE WIND THREAT ACROSS NORTH CENTRAL...NORTHEAST
ILLINOIS...AS WELL AS NORTHWEST INDIANA AROUND THE 9PM TIME FRAME.
ANY DEVELOPMENT IS THEN EXPECTED TO SHIFT SOUTHEAST OF THE CWA
AFTER THE MIDNIGHT TIME FRAME...BUT THUNDERSTORMS STILL NOT BE
OUT OF THE QUESTION AFTER MIDNIGHT. PERSISTENT WAA AIDED BY A
STRONG LLJ COULD PROVIDE CONTINUED ISOLATED TO SCATTERED
DEVELOPMENT THROUGH EARLY WEDNESDAY MORNING.
SHIFTING GEARS TOWARDS WEDNESDAY...A SIGNIFICANT SEVERE WEATHER
OUTBREAK IS APPEARING TO BE POSSIBLE WITH VARYING MODES OF
CONVECTION. HAIL AND TORNADOES ARE POSSIBLE...AND A SIGNIFICANT
WIND THREAT ACROSS THE SOUTHERN HALF OF THE CWA COULD BE MORE
FAVORED THAN THE RUN OF THE MILL STRONG WINDS/GUSTS.
MULTIPLE ROUNDS OF THUNDERSTORMS WILL ONCE AGAIN BE POSSIBLE
ACROSS THE ENTIRE CWA TOMORROW BEGINNING TOMORROW MORNING.
ANTICIPATED UPSTREAM CONVECTION WILL LIKELY SHIFT EAST BY EARLY
WEDNESDAY MORNING BUT WITH LOCATION AND STRENGTH OF THESE STORMS
STILL NOT FULLY KNOWN. AT THIS TIME...IT APPEARS THAT THIS SHOULD
STAY TO THE NORTH OF THE CWA BUT WITH AREAS ACROSS FAR NORTHERN
ILLINOIS OBSERVING THE GREATER THREAT TO OBSERVE THIS
THUNDERSTORM POTENTIAL TOMORROW MORNING...BUT WITH ONCE AGAIN
CONFIDENCE REMAINING LOW. ITS CONCEIVABLE THAT WE COULD BE
DEALING WITH ANOTHER MCS COMPLEX AND ANOTHER ROUND OF HIGH
WINDS/HAIL. ANY REMAINING CONVECTION IS EXPECTED TO SHIFT EAST OF
THE AREA BY MID/LATE MORNING WITH A PERIOD OF DRY WEATHER
POSSIBLE FROM LATE MORNING THROUGH EARLY AFTERNOON.
CURRENT STRONGER AND MORE DEFINED MID LEVEL TROUGH SHIFTING
NORTHEAST ACROSS THE NORTHERN ROCKIES AT THIS TIME WILL MOVE EAST
THROUGH THE NORTHERN PLAINS TONIGHT INTO WEDNESDAY MORNING...AND
THEN DROP SOUTHEAST TOWARDS THE AREA BY MIDDAY. THIS WILL ALLOW
THE LOW OVER THE CENTRAL PLAINS TO SHIFT EAST REACHING THE
IOWA/MISSOURI LINE BY MID DAY...AND THEN CONTINUE EAST ACROSS
NORTH CENTRAL ILLINOIS IN THE AFTERNOON. THIS STRONG WAVE
BRINGING 50-60KT OF MID LEVEL FLOW WILL HELP THIS LOW STRENGTHEN
AS IT MOVES THROUGH THE REGION TOMORROW AFTERNOON. THIS STRONG
FORCING OWING TO THIS MID LEVEL FEATURE AND STRENGTHENING LOW IN
A MODERATELY TO STRONGLY UNSTABLE ENVIRONMENT WILL ALLOW FOR
RAPID GROWTH IN THUNDERSTORM COVERAGE AND INTENSITY STARTING AS
SOON AS THE 19Z TIME FRAME. MORE THAN EFFICIENT EFFECTIVE BULK
SHEAR AS WELL AS STEEP LAPSE RATES MOVING OVERHEAD WILL SUPPORT
EXPLOSIVE DEVELOPMENT. ALTHOUGH SEVERE WEATHER WILL BE POSSIBLE
ACROSS THE ENTIRE CWA TOMORROW AFTERNOON INTO THE EVENING...THE
MORE WIDESPREAD DEVELOPMENT IS EXPECTED FOR AREAS ALONG AND SOUTH
OF A DIXON TO CHICAGO LINE. ITS IN THIS AREA WHERE
MOISTURE/INSTABILITY WILL BE THE GREATEST...JUST ALONG AND SOUTH
OF THE SURFACE BOUNDARY. THE MID TO LATE AFTERNOON TIME FRAME IS
WHEN I EXPECT DEVELOPMENT TO REALLY GET GOING WITH SHEAR/WIND
PROFILES SUPPORTIVE OF DISCRETE CONVECTION WITH ROTATING UPDRAFTS
POSSIBLE. ITS DURING THIS INITIAL TIME FRAME THAT THE THREAT OF
TORNADOES WILL BE THE GREATEST NEAR THE SURFACE LOW OR ALONG THE
BOUNDARY. IT SHOULD NOT TAKE LONG AFTER INITIATION TOMORROW FOR
ANY DEVELOPMENT TO QUICKLY CONGEAL INTO A LINE WITH THEN STRONG
DAMAGING WINDS TO BE THE GREATER THREAT INTO THE AFTERNOON AND
EVENING. DO NOT WANT TO COMPLETELY RULE OUT THE TORNADO THREAT
THEREAFTER AS QLCS SPIN-UPS WILL DEFINITELY REMAIN A POSSIBILITY
AS THIS LINE OF THUNDERSTORMS SHIFTS SOUTHEAST ACROSS THE AREA.
EXPECT THIS COMPLEX OF THUNDERSTORMS TO CONTINUE EAST/SOUTHEAST
INTO THE EVENING WITH THE SEVERE THREAT DIMINISHING MORE TOWARDS
THE 9PM TIME FRAME. ALTHOUGH SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE AFTER MIDNIGHT...THE OVERALL SEVERE THREAT SHOULD BE LOW
AT THAT TIME. EXPECT MID LEVEL TROUGH AND ATTENDANT SURFACE LOW
TO CONTINUE EAST INTO THURSDAY MORNING WITH DRIER CONDITIONS
EXPECTED AS PRECIP SHIELD ALSO EXITS.
RODRIGUEZ
LONG TERM...FRIDAY THROUGH TUESDAY
THE EXTENDED WILL START OUT QUIET AND PLEASANT WITH HIGH PRESSURE
OVERHEAD AND ONSHORE BREEZES ON FRIDAY. HOWEVER...WE WILL QUICKLY
TRANSITION TO A MORE ACTIVE PATTERN AS STRONG UPPER RIDGING
CENTERED OVER THE PLAINS SHIFTS EASTWARD. THE CWA WILL RESIDE ON
THE NORTHERN FRINGE OF THE THE RIDGING...PUTTING US IN THE REGION
OF MODERATE WESTERLIES AND THUS DECENT DEEP LAYER SHEAR. THE
POTENTIAL EXISTS FOR RIDGE RUNNERS PRODUCING CLUSTERS OF
SHRA/TSRA STARTING AS EARLY AS LATE FRIDAY NIGHT INTO EARLY
SATURDAY. THE 12Z ECMWF AND 12Z GFS THEN DIVERGE IN THAT THE GFS
KEEPS US PRIMARILY IN A RING OF FIRE TYPE SET-UP UNTIL LATE
MONDAY...WHILE THE ECMWF HAS A MODESTLY DEEP UPPER TROUGH
BREAKING OFF FROM THE NORTHERN BRANCH WITH TROUGH AND ATTENDANT
SURFACE LOW TRACKING THROUGH WESTERN GREAT LAKES REGION SUNDAY
INTO MONDAY. CONSIDERING UNCERTAINTY...DID NOT MAKE MAJOR CHANGES
TO POPS FROM CONSENSUS BLEND...BUT EVEN DIVERGING MODEL SCENARIOS
KEEP PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS UNTIL AT
LEAST A BRIEF QUIETER STRETCH ARRIVES BY NEXT TUESDAY AND
WEDNESDAY IN THE FORM OF HIGH PRESSURE.
ALSO DID NOT MAKE BIG CHANGES TO TEMPERATURES...BUT SYNOPTICALLY
SUNDAY AND MONDAY BOTH LOOK TO BE WARM AND FAIRLY HUMID AND SOME
GUIDANCE DOES HINT AT MID/UPPER 80S...WHICH MAKES SENSE WITH H85
TEMPS IN THE MID TEENS. THUS COULD SEE TEMPERATURES BOTH DAYS
BEING WARMER THAN CURRENTLY INDICATED. THE POTENTIAL FOR LAKE
BREEZES LENDS UNCERTAINTY TO LAKEFRONT TEMPERATURES SATURDAY
THROUGH MONDAY...WITH HIGHER CONFIDENCE IN SYNOPTIC ONSHORE FLOW
ON TUESDAY.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* STRONG TO SEVERE THUNDERSTORM POTENTIAL AND TIMING LATER TODAY
AND INTO THIS EVENING.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR VIS AND
CIGS POSSIBLE FOR A PERIOD.
* SURFACE WINDS INCREASING OUT OF THE NORTH-NORTHEAST LATER THIS EVENING.
KJB
//DISCUSSION...UPDATED 06Z...
THE MAIN FORECAST CONCERN TODAY WILL BE THE CHANCES OF STRONG TO
SEVERE THUNDERSTORMS LATER THIS AFTERNOON AND INTO THE EVENING.
WATER VAPOR IMAGERY EARLY THIS MORNING INDICATES A SIGNIFICANT MID
LEVEL DISTURBANCE CURRENTLY NEAR THE BLACK HILLS OF SOUTH DAKOTA.
THIS FEATURE WILL BE OF SIGNIFICANT INTEREST FOR TODAY AND INTO THIS
EVENING. THE GUIDANCE CONTINUES TO BRING THIS DISTURBANCE
EAST-SOUTHEASTWARD ACROSS THE AREA BY THIS EVENING. ALTHOUGH THE
AREA WILL REMAIN CAPPED TO SURFACE BASED CONVECTIVE ACTIVITY FOR
MUCH OF THE DAY...THE DYNAMICS ASSOCIATED WITH THIS WAVE SHOULD HAVE
NO PROBLEM COOLING THE MID LEVEL TEMPERATURES AND ELIMINATING THE
CAP LATER THIS AFTER AND EVENING. ONCE THIS OCCURS...SIGNIFICANT
THUNDERSTORM DEVELOPMENT APPEARS TO BE IMMINENT. CURRENT THOUGHTS
ARE LATE THIS AFTERNOON AFTER 21 TO 22 UTC AT THE EASTERN TERMINALS
AND A HOUR OR TWO SOONER AT KRFD. THESE STORMS WILL DEVELOP IN AN
ENVIRONMENT FAVORABLE FOR SEVERE STORMS...WITH LARGE HAIL AND STRONG
DAMAGING WINDS THE MAIN THREATS. HOWEVER...VERY HEAVY RAINFALL WILL
ALSO BECOME A BIG ISSUE...ESPECIALLY THIS EVENING. THIS COULD LEAD TO
LOCALIZED FLOODING AND REDUCTIONS IN THE VIS DOWN UNDER 2 MILES. IT
APPEARS THAT THIS ACTIVITY COULD LAST FOR A 3 TO 6 HOUR WINDOW INTO
THIS EVENING BEFORE CONDITIONS BEGIN TO IMPROVE OVERNIGHT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MODERATE TO HIGH CONFIDENCE IN CHANCES FOR THUNDERSTORMS LATER
TODAY AND TONIGHT.
* MODERATE CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL WITH
LOWER VIS AND CIGS THIS EVENING.
* MODERATE CONFIDENCE IN WIND FORECAST TONIGHT.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THU AND FRI...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TRS
&&
.MARINE...
229 AM CDT
THE MAIN FORECAST CONCERNS ON THE LAKE IS THE THREAT FOR SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS
SOUTHERN LAKE MICHIGAN...AND ALSO A PERIOD OF STRONG NORTHERLY WINDS
LATE TONIGHT AND ON THURSDAY.
DENSE FOG REMAINS ACROSS THE LAKE...ESPECIALLY ACROSS THE NORTHERN
HALF OF THE LAKE....AND I REALLY DONT SEE ANY IMPROVEMENT IN THESE
CONDITIONS UNTIL EITHER LATE THIS AFTERNOON OR THIS EVENING...WHEN
THE WINDS START TO BECOME NORTHERLY. THEREFORE...I HAVE EXTENDED THE
ADVISORY FOR THE OPEN WATERS THROUGH THIS AFTERNOON.
SEVERE THUNDERSTORMS LOOK TO BE A GOOD BET THIS AFTERNOON AND
EVENING...ESPECIALLY ACROSS SOUTHERN LAKE MICHGAN. THESE STORMS WILL
BE CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG DAMAGING WINDS
IN EXCESS OF 50 KT. THE THREAT OF SEVERE STORMS IS QUITE HIGH...SO
KEEP UP TO DATE ON THE LATEST WEATHER INFORMATION.
A SURFACE LOW IS EXPECTED TO PASS SOUTH OF THE LAKE TONIGHT. THIS
WILL SET UP SOME STRONG NORTHERLY WINDS UP TO 30 KT LATE TONIGHT AND
ON THURSDAY. THIS WILL LIKELY RESULT IN SMALL CRAFT ADVISORY
CONDITIONS FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS DURING THIS
TIME. CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE WINDS
ABATE AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 4 PM
WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
113 AM CDT WED JUN 12 2013
.DISCUSSION...
834 PM CDT
A FEW THOUGHTS REGARDING THE THUNDERSTORM THREAT OVERNIGHT AND THE
MODERATE RISK FOR SEVERE WEATHER WEDNESDAY...
THIS EVENING...A WARM FRONT EXTENDS FROM WESTERN IOWA EAST TOWARDS
IOWA CITY...THEN LOSES ITS DEFINITION SOUTHEAST INTO CENTRAL
ILLINOIS. LOW TO MID 70 DEW POINTS ARE POOLING ALONG THE BOUNDARY
TO OUR WEST...BUT AS A 20Z SOUNDING OUT OF DVN SHOWED...A STRONG
CAP IS IN PLACE WITH 825MB TEMPS AROUND 21C. LATEST RAP GUIDANCE
INDICATES THE THE CAP WILL REMAIN IN PLACE THROUGH THE REMAINDER
OF THE EVENING AND TONIGHT. WITH THAT SAID....THE THREAT FOR
SEVERE WEATHER THROUGH THE REMAINDER OF TODAY HAS GREATLY
DIMINISHED. FOCUS TURNS OUT TO THE WEST TONIGHT WHERE A 50-60KT
LOW LEVEL JET IS EXPECTED TO DEVELOP WITH THE BEST MOISTURE
CONVERGENCE FOCUSED OVER CENTRAL NEBRASKA...AND BY MIDNIGHT
TONIGHT SLIGHTLY FARTHER EAST OVER THE MID MISSOURI VALLEY.
DESPITE THE FOCUS BEING WELL OFF TO OUR WEST...THERE IS SOME
ASCENT ALONG THE WARM FRONT SO CAN NOT RULE OUT SOMETHING TRYING
TO DEVELOP THIS EVENING NORTH OF THE WARM FRONT AND MOVING INTO
NORTHERN ILLINOIS...BUT EXPECT COVERAGE TO BE LOW AWAY FROM THE
BETTER FORCING WITH THE LLJ. WITH THAT IN MIND...LOWERED POPS
ACROSS MUCH OF THE CWA FOR THE OVERNIGHT HOURS AND FEEL THEY MAY
STILL BE ON THE HIGH END. CONVECTIVE ALLOWING MODELS STILL SHOW
AN MCS DEVELOPING AT THE NOSE OF THE LLJ TONIGHT...AND BY
DAYBREAK TOMORROW POSSIBLY MOVING INTO NORTHWESTERN ILLINOIS...
BUT MORE LIKELY STAYING NORTH OF THE STATE LINE. EITHER WAY...LLJ
IS VEERING AND WEAKENING BY THAT TIME SO CONVECTION SHOULD BE IN
A WEAKENING PHASE.
THE STORM PREDICTION CENTER CONTINUES TO CARRY US UNDER A MODERATE
RISK WEDNESDAY AND THIS SEEMS TO BE ON TRACK. APPEARS WE WILL BE
UNDER A PRETTY DYNAMIC ENVIRONMENT TOMORROW AS A COUPLED JET SETS
UP WITH THE BEST UPPER LEVEL DIVERGENCE OVER CENTRAL AND NORTHERN
ILLINOIS. MODERATE HEIGHT FALLS ASSOCIATED WITH THE MID LEVEL WAVE
MOVING INTO THE AREA LATE AFTERNOON/EARLY EVENING TOMORROW WILL
PROVIDE LARGE SCALE ASCENT ACROSS THE AREA TO HELP WEAKEN THE CAP.
THE SURFACE LOW TRACKS EAST ACROSS THE MISSISSIPPI VALLEY JUST
SOUTH OF MLI...THOUGH THERE ARE SOME MODELS SUGGESTING THE LOW
TRACK AND RESULTING SEVERE THREAT MAY TRACK SLIGHTLY FARTHER
NORTH. SOME MODELS ALSO INDICATE THE LOW DEEPENING SLIGHTLY
TOMORROW AFTERNOON WITH 2-4MB PRESSURE FALLS OVERSPREADING AREAS
SOUTH OF I-80. THIS WILL ONLY HELP TO ENHANCE WHAT ALREADY LOOKS
TO BE PRETTY STRONG LOW LEVEL HELICITY TOMORROW. DEEP LAYER SHEAR
TOMORROW IS ALSO FORECAST TO BE QUITE STRONG. ALL SAID THERE IS
CONCERN FOR DISCRETE SUPER CELLS DEVELOPING IN THE AFTERNOON WITH
THE WHOLE GAMUT OF SEVERE WEATHER POSSIBLE...LARGE HAIL...
DAMAGING WINDS AND QUITE POSSIBLY TORNADOES. STORMS SHOULD
EVENTUALLY CONGEAL INTO A LINE WITH THE MAIN THREAT TURNING
BECOMING DAMAGING WINDS...THOUGH QLCS TORNADOES WILL STILL BE A
CONCERN. HOW QUICKLY WE TRANSITION FROM DISCRETE SUPER CELLS TO A
LINEAR MCS IS UNCERTAIN. INTERESTING TO NOTE THAT ONE OF THE TOP
CIPS ANALOGS IS JUNE 05 2010 WHICH DID HAVE DISCRETE SUPER CELLS
WITH TORNADOES LATER INTO THE EVENING.
DEUBELBEISS
//PREV DISCUSSION...
300 PM CDT
MAIN FORECAST CONCERNS/CHALLENGES IN THE NEAR TERM ARE WITH
MULTIPLE ROUNDS OF CONVECTION POSSIBLE ACROSS THE ENTIRE CWA
TONIGHT THROUGH WEDNESDAY NIGHT WITH SEVERE WEATHER NOT OUT OF
THE QUESTION THIS EVENING AND OVERNIGHT...BUT WITH A MORE
SIGNIFICANT SEVERE WEATHER OUTBREAK BECOMING INCREASINGLY MORE
POSSIBLE ACROSS A PORTION OF THE CWA ON WEDNESDAY.
IN THE NEAR TERM...CONTINUE TO MONITOR CONVECTION DEVELOPING JUST
SOUTHWEST/SOUTH OF THE CWA AT THIS TIME AS A MID LEVEL IMPULSE
SLIDES EAST ACROSS THE AREA AND ENCOUNTERS SOME WEAK LOW/MID
LEVEL CONVERGENCE IN AND AROUND SHIFTING SURFACE TROUGH ACROSS
IOWA. THIS AREA OF CONVECTION SHOULD CONTINUE EAST/SOUTHEAST WITH
TIME FOR THE REMAINDER OF THE AFTERNOON MAINLY ONLY AFFECTING
AREAS FROM LA SALLE IN ILLINOIS SOUTHEAST TO RENSSELAER IN
INDIANA...SUPPORTED BY THIS WAVE AND CURRENT WAA IN PLACE.
ALTHOUGH INSTABILITY REMAINS RATHER WEAK ACROSS THESE AREAS AS
WELL AS CIN IN PLACE...LATEST TRENDS SUPPORT A NORTHEASTWARD
EXPANSION OF THE INSTABILITY AXIS AS WELL AS WEAKENING CIN.
DESPITE WEAKLY FORCED...THESE CONDITIONS COINCIDING WITH
SUFFICIENT BULK SHEAR COULD SUPPORT AN ISOLATED HAIL/WIND THREAT
THROUGH LATE AFTERNOON. GOING INTO THE EARLY EVENING...COULD SEE
A DRY PERIOD FOR MOST OF NORTHERN ILLINOIS AND NORTHWEST INDIANA
BUT WITH THE POSSIBILITY FOR AN INCREASE IN COVERAGE OF
THUNDERSTORMS ONCE AGAIN LATER IN THE EVENING. THIS IS A DEFINITE
POSSIBILITY ESPECIALLY AS SEVERAL MID LEVEL FEATURES/SPEED MAXES
ARE ANTICIPATED TO ROUND THE MID LEVEL RIDGE...AS WELL AS A
VEERING LLJ STRENGTHENS THIS EVENING.
CONTINUE TO MONITOR THESE MID LEVEL FEATURES TRACKING EAST ACROSS
THE CENTRAL AND NORTHERN PLAINS ON LATEST VISIBLE
SATELLITE...TRYING TO GRAB A HANDLE ON THIS POSSIBILITY OF
INCREASED CHANCES FOR CONVECTION LATER THIS EVENING. THIS IS DUE
TO MOST GUIDANCE VARYING TO SOME DEGREE ON PLACEMENT AS WELL AS
TIMING THIS EVENING...WITH CONFIDENCE NOT THE GREATEST FOR
CONVECTIVE EVOLUTION THIS EVENING. ALTHOUGH LATEST THOUGHTS FOR
THIS EVENING ONCE AGAIN DO INCLUDE THE POSSIBILITY FOR AN
INCREASED CHANCE FOR THUNDERSTORMS AS WELL AS THE POSSIBILITY FOR
SEVERE WEATHER...DAMAGING WINDS AND HAIL ONCE AGAIN THE MAIN
THREATS. MID LEVEL FEATURE MOVING OUT OF THE CENTRAL PLAINS
SHOULD ENCOUNTER STRONG LOW/MID LEVEL CONVERGENCE IN IOWA...AND
SHOULD THEN SEE AN UP-GROWTH IN CONVECTION ACROSS EASTERN IOWA
JUST AFTER THE 7PM TIME FRAME. LATEST GUIDANCE IS SHOWING THAT
THE CURRENT NORTHEASTWARD EXPANSION OF THIS INSTABILITY AXIS WILL
CONTINUE THIS EVENING AND ORIENT ITSELF ACROSS NORTH CENTRAL/EAST
CENTRAL ILLINOIS. THIS INCREASED INSTABILITY AS WELL AS
SUFFICIENT 0-3/0-6KM BULK SHEAR THIS EVENING LENDS ITSELF TO
SUPPORT A POSSIBLE WIND THREAT ACROSS NORTH CENTRAL...NORTHEAST
ILLINOIS...AS WELL AS NORTHWEST INDIANA AROUND THE 9PM TIME FRAME.
ANY DEVELOPMENT IS THEN EXPECTED TO SHIFT SOUTHEAST OF THE CWA
AFTER THE MIDNIGHT TIME FRAME...BUT THUNDERSTORMS STILL NOT BE
OUT OF THE QUESTION AFTER MIDNIGHT. PERSISTENT WAA AIDED BY A
STRONG LLJ COULD PROVIDE CONTINUED ISOLATED TO SCATTERED
DEVELOPMENT THROUGH EARLY WEDNESDAY MORNING.
SHIFTING GEARS TOWARDS WEDNESDAY...A SIGNIFICANT SEVERE WEATHER
OUTBREAK IS APPEARING TO BE POSSIBLE WITH VARYING MODES OF
CONVECTION. HAIL AND TORNADOES ARE POSSIBLE...AND A SIGNIFICANT
WIND THREAT ACROSS THE SOUTHERN HALF OF THE CWA COULD BE MORE
FAVORED THAN THE RUN OF THE MILL STRONG WINDS/GUSTS.
MULTIPLE ROUNDS OF THUNDERSTORMS WILL ONCE AGAIN BE POSSIBLE
ACROSS THE ENTIRE CWA TOMORROW BEGINNING TOMORROW MORNING.
ANTICIPATED UPSTREAM CONVECTION WILL LIKELY SHIFT EAST BY EARLY
WEDNESDAY MORNING BUT WITH LOCATION AND STRENGTH OF THESE STORMS
STILL NOT FULLY KNOWN. AT THIS TIME...IT APPEARS THAT THIS SHOULD
STAY TO THE NORTH OF THE CWA BUT WITH AREAS ACROSS FAR NORTHERN
ILLINOIS OBSERVING THE GREATER THREAT TO OBSERVE THIS
THUNDERSTORM POTENTIAL TOMORROW MORNING...BUT WITH ONCE AGAIN
CONFIDENCE REMAINING LOW. ITS CONCEIVABLE THAT WE COULD BE
DEALING WITH ANOTHER MCS COMPLEX AND ANOTHER ROUND OF HIGH
WINDS/HAIL. ANY REMAINING CONVECTION IS EXPECTED TO SHIFT EAST OF
THE AREA BY MID/LATE MORNING WITH A PERIOD OF DRY WEATHER
POSSIBLE FROM LATE MORNING THROUGH EARLY AFTERNOON.
CURRENT STRONGER AND MORE DEFINED MID LEVEL TROUGH SHIFTING
NORTHEAST ACROSS THE NORTHERN ROCKIES AT THIS TIME WILL MOVE EAST
THROUGH THE NORTHERN PLAINS TONIGHT INTO WEDNESDAY MORNING...AND
THEN DROP SOUTHEAST TOWARDS THE AREA BY MIDDAY. THIS WILL ALLOW
THE LOW OVER THE CENTRAL PLAINS TO SHIFT EAST REACHING THE
IOWA/MISSOURI LINE BY MID DAY...AND THEN CONTINUE EAST ACROSS
NORTH CENTRAL ILLINOIS IN THE AFTERNOON. THIS STRONG WAVE
BRINGING 50-60KT OF MID LEVEL FLOW WILL HELP THIS LOW STRENGTHEN
AS IT MOVES THROUGH THE REGION TOMORROW AFTERNOON. THIS STRONG
FORCING OWING TO THIS MID LEVEL FEATURE AND STRENGTHENING LOW IN
A MODERATELY TO STRONGLY UNSTABLE ENVIRONMENT WILL ALLOW FOR
RAPID GROWTH IN THUNDERSTORM COVERAGE AND INTENSITY STARTING AS
SOON AS THE 19Z TIME FRAME. MORE THAN EFFICIENT EFFECTIVE BULK
SHEAR AS WELL AS STEEP LAPSE RATES MOVING OVERHEAD WILL SUPPORT
EXPLOSIVE DEVELOPMENT. ALTHOUGH SEVERE WEATHER WILL BE POSSIBLE
ACROSS THE ENTIRE CWA TOMORROW AFTERNOON INTO THE EVENING...THE
MORE WIDESPREAD DEVELOPMENT IS EXPECTED FOR AREAS ALONG AND SOUTH
OF A DIXON TO CHICAGO LINE. ITS IN THIS AREA WHERE
MOISTURE/INSTABILITY WILL BE THE GREATEST...JUST ALONG AND SOUTH
OF THE SURFACE BOUNDARY. THE MID TO LATE AFTERNOON TIME FRAME IS
WHEN I EXPECT DEVELOPMENT TO REALLY GET GOING WITH SHEAR/WIND
PROFILES SUPPORTIVE OF DISCRETE CONVECTION WITH ROTATING UPDRAFTS
POSSIBLE. ITS DURING THIS INITIAL TIME FRAME THAT THE THREAT OF
TORNADOES WILL BE THE GREATEST NEAR THE SURFACE LOW OR ALONG THE
BOUNDARY. IT SHOULD NOT TAKE LONG AFTER INITIATION TOMORROW FOR
ANY DEVELOPMENT TO QUICKLY CONGEAL INTO A LINE WITH THEN STRONG
DAMAGING WINDS TO BE THE GREATER THREAT INTO THE AFTERNOON AND
EVENING. DO NOT WANT TO COMPLETELY RULE OUT THE TORNADO THREAT
THEREAFTER AS QLCS SPIN-UPS WILL DEFINITELY REMAIN A POSSIBILITY
AS THIS LINE OF THUNDERSTORMS SHIFTS SOUTHEAST ACROSS THE AREA.
EXPECT THIS COMPLEX OF THUNDERSTORMS TO CONTINUE EAST/SOUTHEAST
INTO THE EVENING WITH THE SEVERE THREAT DIMINISHING MORE TOWARDS
THE 9PM TIME FRAME. ALTHOUGH SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE AFTER MIDNIGHT...THE OVERALL SEVERE THREAT SHOULD BE LOW
AT THAT TIME. EXPECT MID LEVEL TROUGH AND ATTENDANT SURFACE LOW
TO CONTINUE EAST INTO THURSDAY MORNING WITH DRIER CONDITIONS
EXPECTED AS PRECIP SHIELD ALSO EXITS.
RODRIGUEZ
LONG TERM...FRIDAY THROUGH TUESDAY
THE EXTENDED WILL START OUT QUIET AND PLEASANT WITH HIGH PRESSURE
OVERHEAD AND ONSHORE BREEZES ON FRIDAY. HOWEVER...WE WILL QUICKLY
TRANSITION TO A MORE ACTIVE PATTERN AS STRONG UPPER RIDGING
CENTERED OVER THE PLAINS SHIFTS EASTWARD. THE CWA WILL RESIDE ON
THE NORTHERN FRINGE OF THE THE RIDGING...PUTTING US IN THE REGION
OF MODERATE WESTERLIES AND THUS DECENT DEEP LAYER SHEAR. THE
POTENTIAL EXISTS FOR RIDGE RUNNERS PRODUCING CLUSTERS OF
SHRA/TSRA STARTING AS EARLY AS LATE FRIDAY NIGHT INTO EARLY
SATURDAY. THE 12Z ECMWF AND 12Z GFS THEN DIVERGE IN THAT THE GFS
KEEPS US PRIMARILY IN A RING OF FIRE TYPE SET-UP UNTIL LATE
MONDAY...WHILE THE ECMWF HAS A MODESTLY DEEP UPPER TROUGH
BREAKING OFF FROM THE NORTHERN BRANCH WITH TROUGH AND ATTENDANT
SURFACE LOW TRACKING THROUGH WESTERN GREAT LAKES REGION SUNDAY
INTO MONDAY. CONSIDERING UNCERTAINTY...DID NOT MAKE MAJOR CHANGES
TO POPS FROM CONSENSUS BLEND...BUT EVEN DIVERGING MODEL SCENARIOS
KEEP PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS UNTIL AT
LEAST A BRIEF QUIETER STRETCH ARRIVES BY NEXT TUESDAY AND
WEDNESDAY IN THE FORM OF HIGH PRESSURE.
ALSO DID NOT MAKE BIG CHANGES TO TEMPERATURES...BUT SYNOPTICALLY
SUNDAY AND MONDAY BOTH LOOK TO BE WARM AND FAIRLY HUMID AND SOME
GUIDANCE DOES HINT AT MID/UPPER 80S...WHICH MAKES SENSE WITH H85
TEMPS IN THE MID TEENS. THUS COULD SEE TEMPERATURES BOTH DAYS
BEING WARMER THAN CURRENTLY INDICATED. THE POTENTIAL FOR LAKE
BREEZES LENDS UNCERTAINTY TO LAKEFRONT TEMPERATURES SATURDAY
THROUGH MONDAY...WITH HIGHER CONFIDENCE IN SYNOPTIC ONSHORE FLOW
ON TUESDAY.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* STRONG TO SEVERE THUNDERSTORM POTENTIAL AND TIMING LATER TODAY
AND INTO THIS EVENING.
* POTENTIAL FOR VERY HEAVY RAIN THIS EVENING...WITH IFR VIS AND
CIGS POSSIBLE FOR A PERIOD.
* SURFACE WINDS INCREASING OUT OF THE NORTH-NORTHEAST LATER THIS EVENING.
KJB
//DISCUSSION...UPDATED 06Z...
THE MAIN FORECAST CONCERN TODAY WILL BE THE CHANCES OF STRONG TO
SEVERE THUNDERSTORMS LATER THIS AFTERNOON AND INTO THE EVENING.
WATER VAPOR IMAGERY EARLY THIS MORNING INDICATES A SIGNIFICANT MID
LEVEL DISTURBANCE CURRENTLY NEAR THE BLACK HILLS OF SOUTH DAKOTA.
THIS FEATURE WILL BE OF SIGNIFICANT INTEREST FOR TODAY AND INTO THIS
EVENING. THE GUIDANCE CONTINUES TO BRING THIS DISTURBANCE
EAST-SOUTHEASTWARD ACROSS THE AREA BY THIS EVENING. ALTHOUGH THE
AREA WILL REMAIN CAPPED TO SURFACE BASED CONVECTIVE ACTIVITY FOR
MUCH OF THE DAY...THE DYNAMICS ASSOCIATED WITH THIS WAVE SHOULD HAVE
NO PROBLEM COOLING THE MID LEVEL TEMPERATURES AND ELIMINATING THE
CAP LATER THIS AFTER AND EVENING. ONCE THIS OCCURS...SIGNIFICANT
THUNDERSTORM DEVELOPMENT APPEARS TO BE IMMINENT. CURRENT THOUGHTS
ARE LATE THIS AFTERNOON AFTER 21 TO 22 UTC AT THE EASTERN TERMINALS
AND A HOUR OR TWO SOONER AT KRFD. THESE STORMS WILL DEVELOP IN AN
ENVIRONMENT FAVORABLE FOR SEVERE STORMS...WITH LARGE HAIL AND STRONG
DAMAGING WINDS THE MAIN THREATS. HOWEVER...VERY HEAVY RAINFALL WILL
ALSO BECOME A BIG ISSUE...ESPECIALLY THIS EVENING. THIS COULD LEAD TO
LOCALIZED FLOODING AND REDUCTIONS IN THE VIS DOWN UNDER 2 MILES. IT
APPEARS THAT THIS ACTIVITY COULD LAST FOR A 3 TO 6 HOUR WINDOW INTO
THIS EVENING BEFORE CONDITIONS BEGIN TO IMPROVE OVERNIGHT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MODERATE TO HIGH CONFIDENCE IN CHANCES FOR THUNDERSTORMS LATER
TODAY AND TONIGHT.
* MODERATE CONFIDENCE IN A PERIOD OF VERY HEAVY RAINFALL WITH
LOWER VIS AND CIGS THIS EVENING.
* MODERATE CONFIDENCE IN WIND FORECAST TONIGHT.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THU AND FRI...VFR. WX NIL.
SAT THRU MON...VFR. CHC TSRA WITH LOCAL MVFR/IFR.
TRS
&&
.MARINE...
243 PM...MAIN FORECAST CONCERN/CHALLENGE THROUGH WEDNESDAY MORNING
REMAINS DENSE FOG. SOUTHERLY WINDS HAVE PUSHED THE FOG NORTH...
ROUGHLY FROM HOLLAND TO MILWAUKEE. LITTLE IMPROVEMENT SEEN NORTH
OF THERE. SOUTHERLY WINDS DIMINISH THIS EVENING AND BEGIN TURNING
BACK EAST AND THEN NORTHEAST OVERNIGHT INTO WEDNESDAY MORNING...
SO THERE IS SOME POTENTIAL FOR THE FOG TO DRIFT BACK SOUTH. WHILE
CONFIDENCE REMAINS SOMEWHAT LOW...HAVE OPTED TO CONTINUE THE DENSE
FOG ADVISORY FOR ALL OF THE OPEN WATERS THROUGH WEDNESDAY MORNING.
LOW PRESSURE OVER COLORADO WILL MOVE EAST AND DEEPEN TONIGHT...
PASSING ACROSS NORTH CENTRAL ILLINOIS WEDNESDAY AFTERNOON AND THEN
ACROSS NORTHERN INDIANA WEDNESDAY EVENING. THE GRADIENT WILL
TIGHTEN AHEAD OF THIS LOW WITH NORTHEASTERLY WINDS INCREASING
WEDNESDAY AFTERNOON...THEN TURNING NORTHERLY AND INCREASING FURTHER
WEDNESDAY EVENING. A PERIOD OF 15-25 KTS STILL LOOKS ON TRACK AND
OVER THE SOUTHERN THIRD OR QUARTER OF THE LAKE...THERE COULD BE A
PERIOD OF 20-25 KTS WITH GUSTS PERHAPS AS HIGH AS 30 KTS. THE
GRADIENT WILL BE SLOW TO RELAX THURSDAY INTO THURSDAY NIGHT AS HIGH
PRESSURE BUILDS ACROSS THE UPPER MIDWEST AND NORTHERN LAKES...
EVENTUALLY SPREADING ACROSS THE LAKES REGION FRIDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
WEDNESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
633 PM EDT WED JUN 12 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 308 PM EDT WED JUN 12 2013
STRONG TO SEVERE STORMS WILL OCCUR TONIGHT AHEAD OF A COLD FRONT.
RAIN WILL LINGER INTO THURSDAY MORNING...THEN DRY CONDITIONS CAN BE
EXPECTED UNTIL SATURDAY AFTERNOON. A COUPLE OF WEATHER SYSTEMS WILL
KEEP CHANCES FOR RAIN AROUND FROM SATURDAY AFTERNOON INTO NEXT
TUESDAY. TEMPERATURES WILL BE COOLER THAN NORMAL ON THURSDAY BUT
RETURN TO NEAR AVERAGE AND REMAIN THERE FROM THE WEEKEND ON.
&&
.NEAR TERM /LATE THIS AFTERNOON AND TONIGHT/...
ISSUED AT 308 PM EDT WED JUN 12 2013
DECENT CAP SHOULD KEEP CONVECTION AT BAY FOR THE NEXT FEW
HOURS...BUT THEN SCATTERED CONVECTION COULD BREAK THROUGH AS COOLER
AIR FILTERS IN ALOFT. PLENTY OF INSTABILITY AROUND...SO ANY
CONVECTION THAT DOES DEVELOP COULD BECOME SEVERE.
ADDITIONAL THUNDERSTORMS WILL DEVELOP AND MOVE INTO THE AREA THIS
EVENING AND OVERNIGHT AS A COLD FRONT AND UPPER TROUGH MOVES IN. IN
ADDITION THE LEFT EXIT REGION OF AN UPPER JET WILL PROVIDE
ADDITIONAL LIFT.
STILL A HIGH RISK OF SEVERE WEATHER FOR THE EXTREME NORTHERN
FORECAST AREA WITH A MODERATE RISK ELSEWHERE. HIGH INSTABILITY AND
DECENT SHEAR WILL HELP THE POTENTIAL FOR ANY STORM THAT DOES DEVELOP
TO BECOME SEVERE.
THERE IS A CONCERN OVER A POTENTIAL SEVERE SQUALL LINE MOVING ACROSS
NORTHERN INDIANA THIS EVENING INTO EARLY OVERNIGHT. VERY STRONG
WINDS ARE POSSIBLE WITH THIS LINE. THE QUESTION IS HOW FAR SOUTH
WILL IT DEVELOP/MOVE. HRRR MODEL HAS BEEN KEEPING THIS LINE MOSTLY
NORTH OF THE AREA WITH A WEAK TAIL-END OF THE LINE MOVING ACROSS
CENTRAL INDIANA. OTHER MODELS SUCH AS NCEP WRF-NMM SHOW A MUCH
LONGER LINE OF STORMS THAT WILL MOVE ACROSS MOST OF THE AREA.
THUS WHILE SOME SEVERE WEATHER IS LIKELY SOMEWHERE ACROSS THE
NORTHERN FORECAST AREA TONIGHT...UNCERTAINTY IS HIGH ABOUT COVERAGE
OF STORMS ACROSS THE SOUTHERN FORECAST AREA. GIVEN THE FORCING
LISTED EARLIER HAVE DECIDED TO GO AT LEAST LOW END LIKELY POPS MOST
AREAS...WITH CATEGORICAL POPS ACROSS THE FAR NORTH. WILL CONTINUE TO
MENTION SEVERE AND HEAVY RAIN IN PRODUCTS.
FOR TEMPERATURES WENT WITH A BLEND.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 308 PM EDT WED JUN 12 2013
FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE CLOSE
ENOUGH THAT A BLEND CAN BE USED.
SOME LINGERING FORCING WILL CONTINUE ACROSS MAINLY THE SOUTHERN AND
EASTERN FORECAST AREA ON THURSDAY MORNING AS SYSTEM EXITS THE AREA.
WENT LIKELY POPS EXTREME EAST TO LOW CHANCE POPS WEST. ENDED CHANCES
FOR RAIN BY AFTERNOON AS THE SYSTEM PULLS EAST.
HIGH PRESSURE WILL THEN PROVIDE DRY CONDITIONS THURSDAY NIGHT INTO
SATURDAY MORNING.
UPPER WAVES RIDING AROUND AN UPPER RIDGE COULD TRIGGER SOME
CONVECTION ACROSS THE AREA SATURDAY AFTERNOON. UNCERTAINTY REMAINS
HIGH IN THE TIMING AND STRENGTH OF THESE WAVES. THEREFORE ONLY WENT
CHANCE POPS SATURDAY AFTERNOON...MAINLY ACROSS THE NORTHWEST
FORECAST AREA CLOSER TO THE FORCING.
FOR TEMPERATURES THROUGH THE PERIOD WENT WITH A BLEND MOST PERIODS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 227 PM EDT WED JUN 12 2013
MODELS AND WEATHER PREDICTION CENTER SUGGEST A COLD FRONT WILL DROP
SOUTHEAST ACROSS CENTRAL INDIANA ON MONDAY FOLLOWED BY AN UPPER WAVE
ON TUESDAY. MOISTURE STREAMING NORTHEAST OFF THE GULF AHEAD OF THE
FRONT SHOULD ALLOW FOR SCATTERED TO NUMEROUS THUNDERSTORMS PRIOR TO
THE FRONTAL PASSAGE WITH LOWER CHANCES AHEAD OF THE UPPER FEATURE.
REGIONAL INITIALIZATION TEMPERATURES NEAR NORMAL IN THE LOWER TO MID
80S LOOK REASONABLE AND WITH THE SYSTEM TONIGHT TAKING PLENTY OF
FOCUS...WILL NOT MAKE ANY CHANGES.
&&
.AVIATION /DISCUSSION FOR THE 130000Z TAFS/...
ISSUED AT 633 PM EDT WED JUN 12 2013
HIGH CONVECTIVE POTENTIAL ACROSS THE TAF SITES LATER THIS EVENING AS
AN UPPER IMPULSE CURRENTLY ENTERING NORTHWEST ILLINOIS MOVES INTO
NORTHWEST OHIO BY 130600Z. AIR MASS STILL CAPPED OFF...BUT VERY
UNSTABLE. CONVECTION SHOULD RESULT IN EITHER COMPLEX OVER NORTHERN
ILLINOIS TURNING SOUTHEAST...OR DEVELOPMENT ALONG THE TRAILING VORT
TAIL. SHORT TERM MODEL DATA SUGGEST HIGHEST CONVECTIVE POTENTIAL
130100Z-130500Z. BRIEF IFR CONDITIONS...AND GUSTY SHIFTING WINDS IN
THE VICINITY OF THE HEAVIER CELLS.
ADDITIONAL CONVECTION POSSIBLE IN THE WAKE OF THIS WAVE ASSOCIATED
WITH THE COLD FRONT. AT THIS POINT...THINK THE FIRST WAVE WILL SWEEP
OUT MOST OF THE INSTABILITY...BUT IF THIS DOESN/T
HAPPEN...CONVECTIVE THREAT WILL BE HIGHER WITH THE FRONT.
OUTSIDE OF CONVECTION...EXPECTING MVFR CEILINGS TO DEVELOP TOWARDS
SUNRISE THURSDAY IN THE POST FRONTAL ZONE. WILL ALSO KEEP SOME
SURFACE WIND GUSTS AROUND 20 KTS FROM 210-230 DEGREES WELL INTO THE
NIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....MK
AVIATION...JAS
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
430 PM EDT WED JUN 12 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 308 PM EDT WED JUN 12 2013
STRONG TO SEVERE STORMS WILL OCCUR TONIGHT AHEAD OF A COLD FRONT.
RAIN WILL LINGER INTO THURSDAY MORNING...THEN DRY CONDITIONS CAN BE
EXPECTED UNTIL SATURDAY AFTERNOON. A COUPLE OF WEATHER SYSTEMS WILL
KEEP CHANCES FOR RAIN AROUND FROM SATURDAY AFTERNOON INTO NEXT
TUESDAY. TEMPERATURES WILL BE COOLER THAN NORMAL ON THURSDAY BUT
RETURN TO NEAR AVERAGE AND REMAIN THERE FROM THE WEEKEND ON.
&&
.NEAR TERM /LATE THIS AFTERNOON AND TONIGHT/...
ISSUED AT 308 PM EDT WED JUN 12 2013
DECENT CAP SHOULD KEEP CONVECTION AT BAY FOR THE NEXT FEW
HOURS...BUT THEN SCATTERED CONVECTION COULD BREAK THROUGH AS COOLER
AIR FILTERS IN ALOFT. PLENTY OF INSTABILITY AROUND...SO ANY
CONVECTION THAT DOES DEVELOP COULD BECOME SEVERE.
ADDITIONAL THUNDERSTORMS WILL DEVELOP AND MOVE INTO THE AREA THIS
EVENING AND OVERNIGHT AS A COLD FRONT AND UPPER TROUGH MOVES IN. IN
ADDITION THE LEFT EXIT REGION OF AN UPPER JET WILL PROVIDE
ADDITIONAL LIFT.
STILL A HIGH RISK OF SEVERE WEATHER FOR THE EXTREME NORTHERN
FORECAST AREA WITH A MODERATE RISK ELSEWHERE. HIGH INSTABILITY AND
DECENT SHEAR WILL HELP THE POTENTIAL FOR ANY STORM THAT DOES DEVELOP
TO BECOME SEVERE.
THERE IS A CONCERN OVER A POTENTIAL SEVERE SQUALL LINE MOVING ACROSS
NORTHERN INDIANA THIS EVENING INTO EARLY OVERNIGHT. VERY STRONG
WINDS ARE POSSIBLE WITH THIS LINE. THE QUESTION IS HOW FAR SOUTH
WILL IT DEVELOP/MOVE. HRRR MODEL HAS BEEN KEEPING THIS LINE MOSTLY
NORTH OF THE AREA WITH A WEAK TAIL-END OF THE LINE MOVING ACROSS
CENTRAL INDIANA. OTHER MODELS SUCH AS NCEP WRF-NMM SHOW A MUCH
LONGER LINE OF STORMS THAT WILL MOVE ACROSS MOST OF THE AREA.
THUS WHILE SOME SEVERE WEATHER IS LIKELY SOMEWHERE ACROSS THE
NORTHERN FORECAST AREA TONIGHT...UNCERTAINTY IS HIGH ABOUT COVERAGE
OF STORMS ACROSS THE SOUTHERN FORECAST AREA. GIVEN THE FORCING
LISTED EARLIER HAVE DECIDED TO GO AT LEAST LOW END LIKELY POPS MOST
AREAS...WITH CATEGORICAL POPS ACROSS THE FAR NORTH. WILL CONTINUE TO
MENTION SEVERE AND HEAVY RAIN IN PRODUCTS.
FOR TEMPERATURES WENT WITH A BLEND.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 308 PM EDT WED JUN 12 2013
FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE CLOSE
ENOUGH THAT A BLEND CAN BE USED.
SOME LINGERING FORCING WILL CONTINUE ACROSS MAINLY THE SOUTHERN AND
EASTERN FORECAST AREA ON THURSDAY MORNING AS SYSTEM EXITS THE AREA.
WENT LIKELY POPS EXTREME EAST TO LOW CHANCE POPS WEST. ENDED CHANCES
FOR RAIN BY AFTERNOON AS THE SYSTEM PULLS EAST.
HIGH PRESSURE WILL THEN PROVIDE DRY CONDITIONS THURSDAY NIGHT INTO
SATURDAY MORNING.
UPPER WAVES RIDING AROUND AN UPPER RIDGE COULD TRIGGER SOME
CONVECTION ACROSS THE AREA SATURDAY AFTERNOON. UNCERTAINTY REMAINS
HIGH IN THE TIMING AND STRENGTH OF THESE WAVES. THEREFORE ONLY WENT
CHANCE POPS SATURDAY AFTERNOON...MAINLY ACROSS THE NORTHWEST
FORECAST AREA CLOSER TO THE FORCING.
FOR TEMPERATURES THROUGH THE PERIOD WENT WITH A BLEND MOST PERIODS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 227 PM EDT WED JUN 12 2013
MODELS AND WEATHER PREDICTION CENTER SUGGEST A COLD FRONT WILL DROP
SOUTHEAST ACROSS CENTRAL INDIANA ON MONDAY FOLLOWED BY AN UPPER WAVE
ON TUESDAY. MOISTURE STREAMING NORTHEAST OFF THE GULF AHEAD OF THE
FRONT SHOULD ALLOW FOR SCATTERED TO NUMEROUS THUNDERSTORMS PRIOR TO
THE FRONTAL PASSAGE WITH LOWER CHANCES AHEAD OF THE UPPER FEATURE.
REGIONAL INITIALIZATION TEMPERATURES NEAR NORMAL IN THE LOWER TO MID
80S LOOK REASONABLE AND WITH THE SYSTEM TONIGHT TAKING PLENTY OF
FOCUS...WILL NOT MAKE ANY CHANGES.
&&
.AVIATION /DISCUSSION FOR THE 122100Z KIND TAF UPDATE/...
ISSUED AT 430 PM EDT WED JUN 12 2013
AIR MASS STILL CAPPED OFF...SO DESPITE A VERY UNSTABLE
ENVIRONMENT...DON/T THINK THERE IS MUCH OF A CONVECTIVE THREAT IN
THE VICINITY OF KIND FOR THE NEXT SEVERAL HOURS. TAIL END OF UPPER
IMPULSE CURRENTLY PUSHING THROUGH IOWA IS EXPECTED TO MOVE THROUGH
THE LOCAL AREA LATER THIS EVENING. THIS FEATURE SHOULD EVENTUALLY
LEAD TO CONVECTIVE DEVELOPMENT AS IT MOVES INTO THE UNSTABLE AIR
MASS. LATEST SHORT TERM MODEL GUIDANCE SUGGESTS BEST CONVECTIVE
THREAT WILL ARRIVE AT KIND AFTER 130200Z-130300Z...SO WILL BACK OFF
ON THE TIMING OF CONVECTION UNTIL THEN.
PREVIOUS DISCUSSION FOLLOWS.
TIMING OF THUNDERSTORMS IS A BIT PROBLEMATIC. THUS...DECIDED TO
WEIGH HEAVILY ON THE MOST CURRENT MESOSCALE BASED 14Z RAPID REFRESH
REFLECTIVITY PROGS. THEY WOULD SUGGEST THAT SCATTERED
STORMS...POSSIBLY SEVERE...WILL DROP SOUTHEAST ACROSS LAF AND IND
AFTER 23Z THIS EVENING. WITH THE TAF SITES IN A MODERATE RISK OF
SEVERE WEATHER...WENT WITH TEMPO MVFR THUNDERSTORM FOLLOWED BY
PROB30 GROUPS AT THOSE SITES THROUGH 08Z WITH WIND GUSTS TO 40
KNOTS. GUSTS WILL LIKELY NEED TO BE ADJUSTED UPWARD IN LATER
TAFS...CLOSER TO THE TIME OF IMPACT. STORMS SHOULD LIKELY HOLD OFF
UNTIL AFTER 02Z AT BMG. HUF HAS THE LOWEST STORM CHANCES BEING
CLOSER TO THE CAP. BUT STILL...TEMPO THUNDERSTORM GROUP LOOKS GOOD
THERE FROM 01Z-05Z. MODELS SUGGEST AN MVFR OR IFR DECK WILL MOVE IN
AFTER 08Z IN THE WAKE OF THE PRECIPITATION SHIELD. BUT AFTER
15Z...CLOUDS SHOULD BECOME VFR AND THEN BREAKUP. WINDS WILL MOSTLY
BE SOUTHWEST NEAR 15 KNOTS WITH GUSTS TO 20 KNOTS THIS AFTERNOON AND
EVENING AWAY FROM STORMS AND THEN SHIFT TO THE WEST AND NORTHWEST AS
THE FRONT MOVES THROUGH AFTER 08Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....MK
AVIATION...MK/JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/INDIANAPOLIS
WWW.YOUTUBE.COM/INDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
308 PM EDT WED JUN 12 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM...AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW
&&
.SYNOPSIS...
ISSUED AT 308 PM EDT WED JUN 12 2013
STRONG TO SEVERE STORMS WILL OCCUR TONIGHT AHEAD OF A COLD FRONT.
RAIN WILL LINGER INTO THURSDAY MORNING...THEN DRY CONDITIONS CAN BE
EXPECTED UNTIL SATURDAY AFTERNOON. A COUPLE OF WEATHER SYSTEMS WILL
KEEP CHANCES FOR RAIN AROUND FROM SATURDAY AFTERNOON INTO NEXT
TUESDAY. TEMPERATURES WILL BE COOLER THAN NORMAL ON THURSDAY BUT
RETURN TO NEAR AVERAGE AND REMAIN THERE FROM THE WEEKEND ON.
&&
.NEAR TERM /LATE THIS AFTERNOON AND TONIGHT/...
ISSUED AT 308 PM EDT WED JUN 12 2013
DECENT CAP SHOULD KEEP CONVECTION AT BAY FOR THE NEXT FEW
HOURS...BUT THEN SCATTERED CONVECTION COULD BREAK THROUGH AS COOLER
AIR FILTERS IN ALOFT. PLENTY OF INSTABILITY AROUND...SO ANY
CONVECTION THAT DOES DEVELOP COULD BECOME SEVERE.
ADDITIONAL THUNDERSTORMS WILL DEVELOP AND MOVE INTO THE AREA THIS
EVENING AND OVERNIGHT AS A COLD FRONT AND UPPER TROUGH MOVES IN. IN
ADDITION THE LEFT EXIT REGION OF AN UPPER JET WILL PROVIDE
ADDITIONAL LIFT.
STILL A HIGH RISK OF SEVERE WEATHER FOR THE EXTREME NORTHERN
FORECAST AREA WITH A MODERATE RISK ELSEWHERE. HIGH INSTABILITY AND
DECENT SHEAR WILL HELP THE POTENTIAL FOR ANY STORM THAT DOES DEVELOP
TO BECOME SEVERE.
THERE IS A CONCERN OVER A POTENTIAL SEVERE SQUALL LINE MOVING ACROSS
NORTHERN INDIANA THIS EVENING INTO EARLY OVERNIGHT. VERY STRONG
WINDS ARE POSSIBLE WITH THIS LINE. THE QUESTION IS HOW FAR SOUTH
WILL IT DEVELOP/MOVE. HRRR MODEL HAS BEEN KEEPING THIS LINE MOSTLY
NORTH OF THE AREA WITH A WEAK TAIL-END OF THE LINE MOVING ACROSS
CENTRAL INDIANA. OTHER MODELS SUCH AS NCEP WRF-NMM SHOW A MUCH
LONGER LINE OF STORMS THAT WILL MOVE ACROSS MOST OF THE AREA.
THUS WHILE SOME SEVERE WEATHER IS LIKELY SOMEWHERE ACROSS THE
NORTHERN FORECAST AREA TONIGHT...UNCERTAINTY IS HIGH ABOUT COVERAGE
OF STORMS ACROSS THE SOUTHERN FORECAST AREA. GIVEN THE FORCING
LISTED EARLIER HAVE DECIDED TO GO AT LEAST LOW END LIKELY POPS MOST
AREAS...WITH CATEGORICAL POPS ACROSS THE FAR NORTH. WILL CONTINUE TO
MENTION SEVERE AND HEAVY RAIN IN PRODUCTS.
FOR TEMPERATURES WENT WITH A BLEND.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 308 PM EDT WED JUN 12 2013
FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE CLOSE
ENOUGH THAT A BLEND CAN BE USED.
SOME LINGERING FORCING WILL CONTINUE ACROSS MAINLY THE SOUTHERN AND
EASTERN FORECAST AREA ON THURSDAY MORNING AS SYSTEM EXITS THE AREA.
WENT LIKELY POPS EXTREME EAST TO LOW CHANCE POPS WEST. ENDED CHANCES
FOR RAIN BY AFTERNOON AS THE SYSTEM PULLS EAST.
HIGH PRESSURE WILL THEN PROVIDE DRY CONDITIONS THURSDAY NIGHT INTO
SATURDAY MORNING.
UPPER WAVES RIDING AROUND AN UPPER RIDGE COULD TRIGGER SOME
CONVECTION ACROSS THE AREA SATURDAY AFTERNOON. UNCERTAINTY REMAINS
HIGH IN THE TIMING AND STRENGTH OF THESE WAVES. THEREFORE ONLY WENT
CHANCE POPS SATURDAY AFTERNOON...MAINLY ACROSS THE NORTHWEST
FORECAST AREA CLOSER TO THE FORCING.
FOR TEMPERATURES THROUGH THE PERIOD WENT WITH A BLEND MOST PERIODS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 227 PM EDT WED JUN 12 2013
MODELS AND WEATHER PREDICTION CENTER SUGGEST A COLD FRONT WILL DROP
SOUTHEAST ACROSS CENTRAL INDIANA ON MONDAY FOLLOWED BY AN UPPER WAVE
ON TUESDAY. MOISTURE STREAMING NORTHEAST OFF THE GULF AHEAD OF THE
FRONT SHOULD ALLOW FOR SCATTERED TO NUMEROUS THUNDERSTORMS PRIOR TO
THE FRONTAL PASSAGE WITH LOWER CHANCES AHEAD OF THE UPPER FEATURE.
REGIONAL INITIALIZATION TEMPERATURES NEAR NORMAL IN THE LOWER TO MID
80S LOOK REASONABLE AND WITH THE SYSTEM TONIGHT TAKING PLENTY OF
FOCUS...WILL NOT MAKE ANY CHANGES.
&&
.AVIATION /DISCUSSION FOR THE 12/1800Z TAF ISSUANCE/...
ISSUED AT 120 PM EDT WED JUN 12 2013
TIMING OF THUNDERSTORMS IS A BIT PROBLEMATIC. THUS...DECIDED TO
WEIGH HEAVILY ON THE MOST CURRENT MESOSCALE BASED 14Z RAPID REFRESH
REFLECTIVITY PROGS. THEY WOULD SUGGEST THAT SCATTERED
STORMS...POSSIBLY SEVERE...WILL DROP SOUTHEAST ACROSS LAF AND IND
AFTER 23Z THIS EVENING. WITH THE TAF SITES IN A MODERATE RISK OF
SEVERE WEATHER...WENT WITH TEMPO MVFR THUNDERSTORM FOLLOWED BY
PROB30 GROUPS AT THOSE SITES THROUGH 08Z WITH WIND GUSTS TO 40
KNOTS. GUSTS WILL LIKELY NEED TO BE ADJUSTED UPWARD IN LATER
TAFS...CLOSER TO THE TIME OF IMPACT. STORMS SHOULD LIKELY HOLD OFF
UNTIL AFTER 02Z AT BMG. HUF HAS THE LOWEST STORM CHANCES BEING
CLOSER TO THE CAP. BUT STILL...TEMPO THUNDERSTORM GROUP LOOKS GOOD
THERE FROM 01Z-05Z. MODELS SUGGEST AN MVFR OR IFR DECK WILL MOVE IN
AFTER 08Z IN THE WAKE OF THE PRECIPITATION SHIELD. BUT AFTER
15Z...CLOUDS SHOULD BECOME VFR AND THEN BREAKUP. WINDS WILL MOSTLY
BE SOUTHWEST NEAR 15 KNOTS WITH GUSTS TO 20 KNOTS THIS AFTERNOON AND
EVENING AWAY FROM STORMS AND THEN SHIFT TO THE WEST AND NORTHWEST AS
THE FRONT MOVES THROUGH AFTER 08Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....MK
AVIATION...MK
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AREA FORECAST DISCUSSION
NWS GOODLAND KS
1100 PM MDT TUE JUN 11 2013
.UPDATE...
ISSUED AT 901 PM MDT TUE JUN 11 2013
RED FLAG WARNING ALLOWED TO EXPIRE ON TIME.
AT 03Z COLD FRONT EXTENDED FROM NEAR TRENTON NEBRASKA SOUTHWEST
THROUGH SAINT FRANCIS KS TO NEAR BURLINGTON COLORADO. BEHIND THE
FRONT NORTH TO NORTHEAST WINDS GUSTING TO 25 MPH WITH DEWPOINTS
RAPIDLY INCREASING INTO THE 40S TO MID 60S. 01Z HRRR AND TO A
LESSER EXTENT RUC HAVE A PRETTY GOOD HANDLE ON THINGS COMPARED TO
CURRENT OBSERVATIONS SO HAVE FOLLOWED PRETTY CLOSELY. FRONT SHOULD
CLEAR THE EASTERN FORECAST AREA BY 09Z OR SO.
UPDATE ISSUED AT 404 PM MDT TUE JUN 11 2013
ADDED GRAHAM COUNTY TO RED FLAG WARNING BASED ON CURRENT AND
SEVERAL LAST HOURS OF WIND/HUMIDITY OBSERVATIONS.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH WEDNESDAY)
ISSUED AT 108 PM MDT TUE JUN 11 2013
LATEST VISIBLE SATELLITE INDICATES CUMULUS CLOUDS FORMING OVER FAR
NORTHEAST COLORADO EARLY THIS AFTERNOON AHEAD OF AN UPPER LEVEL
SHORT WAVE TROUGH. AT THE SURFACE A LOW PRESSURE WAS LOCATED OVER
FAR NORTHWEST KANSAS WITH A WARM FRONT STRETCHING EAST OF IT OVER
SOUTHERN NEBRASKA. A DRY LINE NOT TOO FAR SOUTH OF THE FRONT
ARCHING OVER FAR NORTHWEST KANSAS THEN EXTENDING SOUTHEAST TO NEAR
HILLY CITY AND HAYS. AS OF EARLY THIS AFTERNOON WINDS ARE STILL
LIGHT OVER MOST OF THE AREA WHERE THE CAP HAS YET TO ERODE.
FOR THE REST OF THE AFTERNOON WINDS SHOULD BEGIN TO INCREASE BY MID
AFTERNOON AS THE CAP ERODES AND ALLOWS THE STRONGER WINDS TO MIX TO
THE GROUND. WITH THE DRY LINE WELL INTO THE AREA BY LATE AFTERNOON
RELATIVE HUMIDITIES BEHIND IT WILL FALL TO AROUND 10 PERCENT. THE
COMBINATION OF GUSTY WINDS AND LOW RELATIVE HUMIDITIES WILL CREATE
HAZARDOUS FIRE WEATHER CONDITIONS FOR MUCH OF THE AREA. SEE THE
FIRE WEATHER SECTION FOR MORE INFORMATION. DURING THE LATTER HALF
OF THE AFTERNOON LIFT INCREASES OVER THE AREA AHEAD OF A MID LEVEL
SHORT WAVE TROUGH. THE LIFT AND MOISTURE WILL BE CO-LOCATED OVER
THE CENTRAL AND EASTERN PART OF THE AREA...WITH LESS MOISTURE TO THE
WEST AND LESS LIFT TO THE EAST. WITH A DEEP DRY LAYER UP TO 500MB
AND MOST UNSTABLE MIXED 1KM CAPE RANGING FROM 500-1500 J/KG...AM
EXPECTING STORM COVERAGE TO BE VERY SPARSE AT BEST THIS AFTERNOON.
THE MAIN THREAT WITH THESE STORMS WILL BE STRONG TO SEVERE WIND
GUSTS THROUGH EARLY EVENING.
THIS EVENING THE LIFT WILL MOVE EAST AHEAD OF THE MID LEVEL TROUGH.
BY MID EVENING THE ENVIRONMENT BECOMES STABLE CAUSING ANY STORMS
TO COME TO AN END. OVERNIGHT A COOLER AIR MASS WILL
MOVE INTO THE AREA.
WEDNESDAY CAPPING AND AN UPPER LEVEL RIDGE WILL KEEP THE AREA DRY.
HIGHS WILL BE SOMEWHAT COOLER THAN YESTERDAY BUT STILL ABOVE NORMAL
AND WINDS WILL BE LIGHT TO BREEZY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 226 PM MDT TUE JUN 11 2013
WEDNESDAY NIGHT AND THURSDAY THE UPPER RIDGE REMAINS IN PLACE OVER
THE HIGH PLAINS WITH WARM TEMPERATURES EXPECTED TO CONTINUE.
RETURN FLOW AROUND THE SURFACE HIGH PRESSURE AREA OVER THE
NORTHERN PLAINS WILL BRING ADDITIONAL NEAR SURFACE MOISTURE INTO
THE AREA. IN ADDITION TO A DEEPENING LEE SURFACE TROUGH THAT
PROVIDES FOCUS FOR THUNDERSTORMS DEVELOPMENT...A SHORT WAVE TROUGH
AHEAD OF THE MAIN UPPER TROUGH OVER THE PACIFIC NORTHWEST RIDES
UP THROUGH THE BACK SIDE OF THE UPPER RIDGE THURSDAY NIGHT FOR A
CHANCE OF THUNDERSTORMS ACROSS THE FORECAST AREA THURSDAY
AFTERNOON THROUGH THURSDAY NIGHT.
THE SURFACE LOW PRESSURE CENTER AND COLD FRONT MOVES THROUGH THE
FORECAST AREA LATE FRIDAY AS THE RIDGE AXIS MOVES EAST OF THE
REGION AND THE MAIN UPPER TROUGH MOVES ACROSS THE U.S./CANADIAN
BORDER AREA...FLATTENING THE RIDGE ON SATURDAY AND PRODUCING A
DIRTY ZONAL FLOW ACROSS THE CENTRAL HIGH PLAINS REGION THROUGH
SUNDAY. THIS WILL BRING SLIGHTLY COOLER TEMPERATURES AND ANOTHER
ROUND OF THUNDERSTORMS FRIDAY AND SATURDAY AFTERNOON AND EVENING.
ANOTHER RIDGE BEGINS TO AMPLIFY OVER THE ROCKIES BY LATE
SUNDAY...MOVING INTO POSITION OVER THE HIGH PLAINS REGION BY THE
FIRST PART OF NEXT WEEK WITH WARMER TEMPERATURES AND ONLY ISOLATED
THUNDERSTORMS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1100 PM MDT TUE JUN 11 2013
KGLD...VFR EXPECTED THROUGH THE PERIOD. COLD FRONT HAS MOVED
THROUGH THE TERMINAL. FOR THE NEXT 24 HOURS NORTH TO NORTHWEST
WINDS AROUND 10KTS WILL BECOME A LITTLE GUSTY BY 15Z AND CONTINUE
THROUGH 20Z BEFORE DECREASING AND VEERING TO THE NORTHEAST THEN
EAST AT 10KTS OR LESS THROUGH THE REST OF THE TAF PERIOD.
KMCK...MESOSCALE SITUATION SIMILAR TO KGLD. COLD FRONT EXPECTED TO
PUSH THROUGH THE TERMINAL IN THE 06Z-07Z TIME FRAME WITH NORTHWEST
WINDS GUSTING AROUND 25KTS. BY 09Z WEST/NORTHWEST WINDS
EXPECTED...INCREASING FROM THE NORTHWEST AT 15G25KTS BY 15Z AND
CONTINUING THROUGH 21Z WHEN THEY VEER TO THE NORTHEAST THEN EAST
AT 10KTS OR LESS. STILL LOOKING AT THE POSSIBILITY OF MVFR/IFR
CIGS IN THE 10Z-14Z TIMEFRAME...FOR NOW HAVE A TEMPO
GROUP...OTHERWISE VFR EXPECTED.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...JTL
LONG TERM...LOCKHART
AVIATION...99
AREA FORECAST DISCUSSION
NWS PADUCAH KY
225 PM CDT WED JUN 12 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 225 PM CDT WED JUN 12 2013
HOT HUMID CONDITIONS PREVAIL ACROSS THE FOUR STATE REGION WITH
HEAT INDEX VALUES FROM THE UPPER 90S TO JUST ABOVE 100F. LAKE
WIND ADVISORY OK FOR NOW AND WILL RUN THROUGH EARLY EVENING WITH
GUSTY SOUTHWEST WINDS CONTINUING.
WVAPOR LOOP SHOWS A VIGOROUS WAVE MOVING INTO SW MINNESOTA AND
SHOULD BE THE FOCUS FOR SIGNIFICANT SEVERE WEATHER OFF TO OUR
NORTH FROM PORTIONS OF IOWA INTO ILLINOIS/INDIANA AND OHIO. THE
QUESTION FOR OUR AREA...IS HOW FAR SOUTH AND WEST CONVECTION WILL
DEVELOP WITH THIS MID LEVEL LOW AND ASSOC SURFACE FRONT THAT WILL
MOVE THROUGH THE REGION LATER TONIGHT INTO EARLY THURSDAY MORNING.
THE HIGH RESOLUTION/MESOSCALE MODELS ARE VARIABLE. A COUPLE OF
4KM MODELS DEVELOP CONVECTION ALL THE WAY TO THE MISSISSIPPI
RIVER. WHILE VARIANTS OF THE HRRR STANDARD AND ENSEMBLE COMPOSITE
DATA SUGGEST A LIMITED CHANCE INTO THE KEVV TRI-STATE IF ANYTHING
AT ALL...AND NOTHING WEST AND SOUTH. GIVEN THE STRONG VEERING MID
LEVEL FLOW AND FALLING HEIGHTS/WEAKENING CAP...THINK IT PRUDENT WE
MAINTAIN POPS FOR CONVECTION TONIGHT INTO MIDDAY THURSDAY FOR NOW
WITH MID RANGE CHANCE POPS KEVV TRI-STATE...LOWERING TO SLIGHT
CHANCE TOWARD THE I-55 CORRIDOR. WOULD NOT BE SURPRISED EITHER WAY
HOW THINGS PAN OUT. AND SHOULD CONVECTION TAKE SHAPE IN OUR
AREA...IT COULD BE SEVERE WITH DAMAGING WINDS THE MAIN HAZARD.
HIGH PRESSURE WILL BUILD IN AND RESULT IN DRY WEATHER FOR THURSDAY
NIGHT THROUGH FRIDAY NIGHT. IN THE WAKE OF THE FRONT AND WITH THE
HIGH BUILDING IN...WE WILL RID THE SHORT LIVED HEAT EPISODE.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 225 PM CDT WED JUN 12 2013
AT THE BEGINNING OF THIS PERIOD A VERY SHARP...BUT NARROW AMPLITUDE
NORTH TO SOUTH ORIENTED MID-LEVEL RIDGE IS PARKED JUST TO THE WEST
OF THE WFO PAH FORECAST AREA...EXTENDING SOUTH TO THE GULF OF
MEXICO. THE MEAN MOISTURE FLOW AT LOW LEVELS IS ORIENTED FROM THE
SOUTHEAST...WITH HIGH LEVEL MOISTURE MOVING OVER THE RIDGE AND
DIVING SHARPLY SOUTH-SOUTHEAST OVER THE WFO PAH FORECAST AREA FROM
THE UPPER MIDWEST. THERE WILL BE A FAIRLY NARROW...BUT ROBUST
CORRIDOR OF INSTABILITY AND SHEAR TO WORK WITH...BUT THIS SHOULD BE
ENOUGH TO WARRANT THE MENTION OF SHOWERS AND THUNDERSTORMS FROM
NORTHWEST TO SOUTHEAST AS THE WEEKEND PROGRESSES. A SERIES OF MINOR
IMPULSES ROTATING AROUND THE MID-LEVEL RIDGE IN THE MUCH FASTER
WESTERLIES MAY GENERATE NON-DIURNAL RAIN CHANCES. THE BIG KEY WILL
BE THE DEGREE OF DEEP LAYER MOISTURE AVAILABLE FOR CONVECTIVE
ACTIVITY. FOR NOW...KEEPING MOST OF THE WEEKEND RAIN CHANCES IN THE
30 TO 50 PERCENT RANGE FOR POPS.
BY THE TIME SUNDAY AFTERNOON AND EVENING ROLLS AROUND THE MID-LEVEL
RIDGE FLATTENS...SUPPORTING A MUCH MORE ENERGETIC WESTERLY FLOW AND
FORCING OVER THE AREA. THE TRAJECTORY OF MOISTURE IS ALSO MORE
SOUTHERLY AND TARGETED TOWARD THE WFO PAH FORECAST AREA. WITH THIS
IN MIND...RAIN CHANCES WERE INCREASED FROM HIGH CHANCE TO LIKELY BY
EARLY MONDAY...FOCUSED OVER THE SOUTHERN 2/3RDS OF THE WFO PAH
FORECAST AREA. THE RAIN CHANCES ARE ALSO AIDED BY A PROGRESSIVE
SHORTWAVE EXPECTED TO MOVE THROUGH THE AREA DURING THE DAY MONDAY. A
MORE DOMINANT RIDGING TAKES PLACE LATE MONDAY...BRIEFLY REDUCING
CHANCES FOR RAIN DURING THE EVENING HOURS. HOWEVER...UNTIL RIDGING
ALOFT CAPS THE ATMOSPHERE BY MID-WEEK...ANTECEDENT SURFACE
BOUNDARIES/STATIONARY FRONTS SHOULD SUPPORT A SMALL DIURNAL CHANCE
FOR SHOWERS AND THUNDERSTORMS.
GIVEN THE TRAJECTORY OF THE MOISTURE AND VARIABLE CLOUD COVER...THE
HEAT INDEX VALUES SHOULD NOT BE AS STRESSFUL AS WHAT WE ARE
EXPERIENCING TODAY. OTHERWISE...LITTLE CHANGE IN MAX/MIN
TEMPERATURES THROUGH THE PERIOD.
&&
.AVIATION...
ISSUED AT 1137 AM CDT WED JUN 12 2013
GUSTY WSW WINDS EXPECTED THIS AFTERNOON WITH SOME DIURNAL CU.
CONVECTION IS POSSIBLE TONIGHT AND INTO EARLY THURSDAY...ESP KEVV
AND KOWB. LEAST LIKELY KPAH AND KCGI. HOWEVER GIVEN UNCERTAINTY...WILL
LIKELY KEEP IT OUT OF THE TERMINAL FORECASTS AT THIS TIME. WINDS
WILL TURN TO THE WEST AND THEN NORTHWEST THURSDAY MORNING AS A
FRONT MOVES ACROSS THE AREA.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...LAKE WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR ILZ075>078-
080>094.
MO...LAKE WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR MOZ076-086-
087-100-107>112-114.
IN...LAKE WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR INZ081-082-
085>088.
KY...LAKE WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR KYZ001>022.
&&
$$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1252 AM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK INTO THE GULF OF MAINE TONIGHT THEN EXIT
ACROSS SOUTHERN NOVA SCOTIA LATE WEDNESDAY. HIGH PRESSURE WILL
BUILD OVER THE AREA THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
MIDNIGHT UPDATE...INCREASED RAIN COVERAGE OVER THE NORTH AND
DECREASED COVERAGE DOWNEAST. RAISED TEMPS A BIT TOO WITH HUMID AIR
AND CLOUD COVER KEEPING AIR FROM COOLING.
PREV DISC: MAIN CHALLENGES WILL BE QPF AND PLACEMENT.
THE FLOOD WATCH FOR THE CENTRAL AND DOWNEAST AREAS HAS BEEN
DROPPED AS MAJOR FLOODING NOT EXPECTED/THIS EVENT. SO FAR, STORM
TOTALS HAVE BEEN 0.25 TO AROUND 0.50 FROM THE CENTRAL HIGHLANDS
DOWN TO THE COAST AND THIS HAS BEEN MAINLY INTERIOR DOWNEAST AND
COAST. FURTHER NORTH, AMOUNTS OF 005 TO 0.10 MAINLY FROM HOULTON TO
MILLINOCKET W/SOME ISOLATED AREAS OF UP TO 0.25 SUCH AS KNOWLES
CORNER DUE TO SOME CONVERGENCE. 18Z RADAR HAD LARGE AREA OF
MAINLY LIGHT RAIN ACROSS NORTH-CENTRAL AREAS ALIGNING W/A THETA E
AXIS STRETCHING FROM NEW BRUNSWICK BACK ACROSS WSW MAINE. ANOTHER
AREA OF RAIN DOWN ACROSS DOWNEAST AND EASTERN AREAS LIFTING NORTH.
THIS AREA WILL MOVE INTO A MORE FAVORABLE ENVIRONMENT AND CONVERGE
WITH THE AREA ACROSS THE NORTH CENTRAL REGION. FURTHER NORTH
ACROSS THE CROWN OF MAINE, SUBSIDENCE FROM THE UPPER RIDGE IS
HOLDING PRECIP SHIELD AT BAY.
LOW PRES AT THE SFC WILL MOVE INTO THE GULF OF MAINE AND WILL STRENGTHEN
TONIGHT INTO WEDNESDAY. THE LATEST RUC AND HRRR HANDLE THIS WELL
AND LEANED CLOSE TO THIS BLEND INTO TONIGHT. THEREFORE, RAIN IS
EXPECTED TO FILL IN TONIGHT AS THE LOW MOVES EAST. LLVL CONVERGENCE
AND FORCING AT THE MID LEVELS WILL AID IN ENHANCING AND EXPANDING
THE RAINFALL. ATTM, PUSHED POPS UP TO NEAR 100% ACROSS THE WESTERN
AROOSTOOK AND NW PISCATAQUIS REGION TO MATCH UP W/THE RADAR TRENDS
AND RUC PLACEMENT. AS LOW PRES LIFTS ACROSS THE GULF OF MAINE
TONIGHT INTO WEDNESDAY, THE RAIN SHIELD WILL PIVOT SOUTHWARD AS
NORTHERN AND WESTERN AREAS GET UNDER NVA AND LESS FORCING. THE BEST
CONVERGENCE AND FORCING WILL BE ACROSS THE INTERIOR DOWNEAST AND
EASTERN AREAS ON WEDNESDAY AS DEPICTED WELL BY THE ECMWF AND NOW
THE GFS. AN AREA OF ENHANCED RAINFALL IS EXPECTED IN THESE AREAS
AS THE 700MBS LOW MOVES ACROSS THE REGION W/FRONTOGENETICAL
FORCING SETTING UP. DECIDED TO LEAN W/THE NERFC QPF TO ACCOUNT FOR
THIS THINKING W/AND ADDITIONAL 0.75 INCHES OF RAINFALL FROM
12-00Z. RAINFALL WILL BEGIN TO WIND DOWN LATER IN THE AFTERNOON AS
THE LOW GETS CAPTURED AND PULLS FURTHER EAST ACROSS THE SOUTHERN
TIP OF NOVA SCOTIA. NORTHERN AND WESTERN AREAS WILL DRY OUT W/RAIN
ENDING.
TEMPERATURES TONIGHT WILL BE HELD DUE TO THE CLOUDS AND RAIN
MAINLY RUNNING IN THE 50S CWA WIDE. COOLER FOR WEDNESDAY USING A
BLEND OF THE NAM12/GMOS AND ECMWFMOS WHICH SHOWED LOW TO MID 60S
NORTH AND WEST AND UPPER 50S TO AROUND 60S CENTRAL AND DOWNEAST
AREAS. A NE WIND PICKING UP AT 10 TO 20 MPH ON WEDNESDAY ON
BACKSIDE OF THE LOW WILL AID IN THE COOLER TEMPERATURES.&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
LOW PRESSURE NEAR SOUTHERN NOVA SCOTIA CONTINUES TO MOVE OFF TO
THE EAST AT THE BEGINNING OF THIS PERIOD WHILE WEAK HIGH PRESSURE
BUILDS IN OVER THE STATE EARLY THURSDAY. LOW PRESSURE IS THEN
EXPECTED TO PASS TO THE SOUTH FRIDAY. WILL BLEND THE
NAM...GFS...SREF AND ECMWF FOR POPS AND QPF WITH HIGHEST POPS
EXPECTED SOUTH FRIDAY. FOR WIND GRIDS WILL BLEND THE NAM12 AND
GMOS. WILL USE 150 PERCENT OF SUSTAINED WIND SPEED FOR GUSTS.
TEMPERATURE INITIALIZED WITH THE GMOS. WILL ADD 3 DEGREES FOR
MINIMUM TEMPERATURE AND 2 DEGREES TO MAXIMUM TEMPERATURE TO
COMPENSATE FOR LOW GMOS BIAS LAST SEVERAL DAYS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
LOW PRESSURE WILL BE PULLING AWAY FROM THE FORECAST AREA FRIDAY
NIGHT, FOLLOWED BY A RIDGE OF HIGH PRESSURE. THE HIGH WILL MOVE
ACROSS THE EASTERN CONUS SATURDAY AND SUNDAY, LEADING TO A MOSTLY
DRY WEEKEND. HOWEVER, PRECIPITATION RETURNS EARLY NEXT WEEK AS A
SERIES OF DISTURBANCES MOVES THROUGH THE NEARLY ZONAL FLOW ALOFT.
TEMPERATURES WILL BE SEASONABLE THROUGH THE PERIOD.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: VFR ACROSS THE FAR NORTHERN TERMINALS THIS EVENING
DROPPING TO MVFR TONIGHT INTO EARLY WEDNESDAY. IMPROVEMENT TO VFR
IS EXPECTED BY WEDNESDAY NIGHT INTO THURSDAY. FROM KHUL DOWN INTO
KBGR AND KBHB, MVFR TO IFR TONIGHT INTO WEDNESDAY AFTERNOON AND
THEN CONDITIONS LOOK LIKE THEY WILL IMPROVE TO VFR WEDNESDAY NIGHT
INTO THURSDAY. THERE IS POTENTIAL FOR SOME MVFR AND POSSIBLY IFR
BY FRIDAY W/A ESE FLOW SETTING UP. VFR EXPECTED FOR THE WEEKEND.
SHORT TERM: VFR CONDITIONS EXPECTED THURSDAY AND FRIDAY. ONLY
EXCEPTION IS KBGR AND KBHB WHERE IFR/MVFR CONDITIONS POSSIBLE
THURSDAY NIGHT INTO FRIDAY.
&&
.MARINE...
NEAR TERM: UPDATE 1900L: ADDED AREAS OF FOG INTO WED AM...
PREV DISC: SCA FOR HAZARDOUS SEAS IN PLACE. A SOUTHERLY SWELL IS
OUT THERE ATTM W/WAVES OF 3 FT AND A 8-9 SECOND PERIOD. A BRIEF
WINDOW(3-6HR) OF WINDS APCHG 25 KTS IS EXPECTED ON WEDNESDAY ON
THE BACKSIDE OF THE LOW. WINDS WILL COME DOWN AS THE LOW PULLS
TOWARD NOVA SCOTIA. WAVES HEIGHTS CLIMBING ATTM TO 5-6 FT PER THE
LATEST OBS. DECIDED TO BRING WAVES UP A FOOT TO HIT 7-8 FT W/THE
LONG SOUTHERLY FETCH. THE LATEST SWAN GUIDANCE HAD THIS HANDLED WELL.
SHORT TERM: FOR WIND WILL USE A 50/50 BLEND OF THE NAM12 AND
GFS40. HAVE LOWERED SUSTAINED WIND SPEED BY 20 PERCENT TO
COMPENSATE FOR MARINE LAYER. FOR GUST SPEED WILL USE 125 PERCENT
OF SUSTAINED WINDS. FOR WAVES: NORTHEAST WIND WAVES PRIMARY WAVE
GROUP THURSDAY AND FRIDAY WITH SECONDARY SOUTHERLY SWELL OUT OF
SOUTH (2 FEET/9 SECONDS). WILL USE NAM/SWAN TO INITIALIZE WAVE
GRIDS AND WILL REDUCE WAVE HEIGHT 1 FOOT TO COMPENSATE FOR HIGH
BIAS EXPECTED FROM NAM WINDS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM EDT
THURSDAY FOR ANZ050>052.
&&
$$
NEAR TERM...BLOOMER
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1035 PM EDT THU JUN 13 2013
.SYNOPSIS...
BEHIND LOW PRESSURE HEADING TOWARD THE EAST COAST...IT WILL BE
MUCH COOLER AND LESS HUMID TONIGHT INTO FRIDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
ADJUSTED POPS FOR DIMINISHING SHOWERS ACROSS THE NORTH ASSOCIATED
WITH BACK END OF LOW PRESSURE/UPPER TROUGH AXIS AND SKY COVER AS
WESTERN PART OF FORECAST AREA HAS BEGUN TO CLEAR OUT. PRESSURE
GRADIENT BEHIND EXITING SURFACE LOW OVER EASTERN PA WILL KEEP
GUSTY WEST TO NORTHWEST WINDS IN SOLATED AREAS FOR A COUPLE MORE
HOURS. TEMPERATURES WILL BE COOLER THAN NORMAL.
FOR FRIDAY...A SHORTWAVE ON THE BACKSIDE OF UPPER LEVEL SYSTEM WILL
BRING ENOUGH INSTABILITY FOR A LOW CHANCE OF SHOWERS IN THE
AFTERNOON...ESPECIALLY ALONG THE RIDGES. TEMPERATURES WILL BE
ABOUT 5 TO 8 DEGREES BELOW AVERAGE TONIGHT AND FRIDAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
SURFACE HIGH PRESSURE WILL KEEP THE REGION DRY FRIDAY NIGHT
THROUGH SATURDAY WITH TEMPERATURES RETURNING TO NEAR AVERAGE
SATURDAY AFTER A COOL START.
NEXT SHORTWAVE WILL BE RACING EAST LATER SATURDAY NIGHT WITH WARM
ADVECTION INCREASING CLOUDS AND SHOWER CHANCES BY DAYBREAK
SUNDAY. UPPER POPS TO LIKELY FOR SUNDAY AS MODELS IN GOOD
AGREEMENT ON DEEP MOISTURE AND LIFT AS WEAK FRONT CROSSES THE
REGION AND LOOKS TO STALL NEAR OF THE MASON DIXON LINE LATE DAY
SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A STNRY FNT NR THE UPR OH VLLY SUN NGT INTO MON NGT WL CONT
SHWR/TSTM CHCS. AN UPR LVL TROF AND CDFNT ARE EXP TO CROSS THE GT
LKS TUE WITH BETTER CHCS FOR SHWRS/TSTMS. HIGH PRES BLDS IN WITH
DRY WEA WED AND THU. OVERALL TEMPS SHOULD BE NR OR SLIGHTLY BLO
SEASONAL AVGS.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
LOWER CLOUDS ASSOCIATED WITH NE STORM SYSTEM TRYING TO LIFT ENE.
HOWEVER, BROADER CYCLONIC FLOW AS SYSTEM PULLS NE WILL BRING
CONTINUED LOWER LEVEL STRATCU MOISTURE PLUME FROM NORTH AND WITH
LAKE TRAJECTORY. HRRR SUGGESTING SOME CLEARING OVERNIGHT BUT EVEN
IT DEVELOPS LOWER CEILINGS OFF THE LAKE BY MORNING. WRF GOES-R
SUGGESTS SOME SCATTERING OUT EARLY BUT THEN BRINGS STRATO- CU BACK
IN OVERNIGHT. WILL CONTINUE WITH SC DECK OVERNIGHT GENERALLY
BROKEN. WILL GO SKC AT ZZV. SOME GRADIENT APPEARS TO KEEP UP
OVERNIGHT BUT GUSTS SHOULD DIMINISH. AS SUGGESTED BY HRRR WILL
BRING SOME LOWER STRATUS IN AROUND 09Z BUT WITH SOME GRADIENT
WILL NOT GO VERY LOW ON ANY BR. NORTHWEST FLOW TO CONTINUE ON
FRIDAY. COULD BE A SPRINKLE OR TWO AROUND AND WENT GENERALLY WITH
BKN SC DECK IN PA AND SCATTERED IN OH.
.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
FINALLY CYCLONIC FLOW DIMINISHED FRIDAY NIGHT AS HIGH PRESSURE
BUILDS INTO REGION. EXPECT VFR THROUGH SUNDAY MORNING. THEN NEXT
SYSTEM MOVES INTO AREA FOR THE REMAINDER OF SUNDAY INTO EARLY
MONDAY...BRIEF HIGH PRESSURE THROUGH MIDDAY MONDAY AND THEN ANOTHER
STORM SYSTEM AND ASSOCIATED FRONT THROUGH TUESDAY WITH SOME
RESTRICTIONS POSSIBLE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
730 PM EDT THU JUN 13 2013
.SYNOPSIS...
BEHIND LOW PRESSURE HEADING TOWARD THE EAST COAST...IT WILL BE
MUCH COOLER AND LESS HUMID TONIGHT INTO FRIDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
ADJUSTED POPS FOR NARROW BAND OF SHOWERS MOVING SOUTH ASSOCIATED
WITH BACK END OF LOW PRESSURE/UPPER TROUGH AXIS AND SKY COVER AS
WESTERN PART OF FORECAST AREA HAS BEGUN TO CLEAR OUT. THE SHOWERS
SHOULD END BY MID EVENING AS DRY AIR MOVES EASTWARD. PRESSURE
GRADIENT BEHIND EXITING SURFACE LOW OVER EASTERN PA WILL KEEP
GUSTY WEST TO NORTHWEST WINDS THIS EVENING AND MUCH COOLER
TEMPERATURES.
FOR FRIDAY A SHORTWAVE ON THE BACKSIDE OF UPPER LEVEL SYSTEM WILL
BRING ENOUGH INSTABILITY FOR A LOW CHANCE OF SHOWERS IN THE
AFTERNOON...ESPECIALLY ALONG THE RIDGES. TEMPERATURES WILL BE
ABOUT 5 TO 8 DEGREES BELOW AVERAGE TONIGHT AND FRIDAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
SURFACE HIGH PRESSURE WILL KEEP THE REGION DRY FRIDAY NIGHT
THROUGH SATURDAY WITH TEMPERATURES RETURNING TO NEAR AVERAGE
SATURDAY AFTER A COOL START.
NEXT SHORTWAVE WILL BE RACING EAST LATER SATURDAY NIGHT WITH WARM
ADVECTION INCREASING CLOUDS AND SHOWER CHANCES BY DAYBREAK
SUNDAY. UPPER POPS TO LIKELY FOR SUNDAY AS MODELS IN GOOD
AGREEMENT ON DEEP MOISTURE AND LIFT AS WEAK FRONT CROSSES THE
REGION AND LOOKS TO STALL NEAR OF THE MASON DIXON LINE LATE DAY
SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A STNRY FNT NR THE UPR OH VLLY SUN NGT INTO MON NGT WL CONT
SHWR/TSTM CHCS. AN UPR LVL TROF AND CDFNT ARE EXP TO CROSS THE GT
LKS TUE WITH BETTER CHCS FOR SHWRS/TSTMS. HIGH PRES BLDS IN WITH
DRY WEA WED AND THU. OVERALL TEMPS SHOULD BE NR OR SLIGHTLY BLO
SEASONAL AVGS.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
LOWER CLOUDS ASSOCIATED WITH NE STORM SYSTEM TRYING TO LIFT ENE.
HOWEVER, BROADER CYCLONIC FLOW AS SYSTEM PULLS NE WILL BRING
CONTINUED LOWER LEVEL STRATCU MOISTURE PLUME FROM NORTH AND WITH
LAKE TRAJECTORY. HRRR SUGGESTING SOME CLEARING OVERNIGHT BUT EVEN
IT DEVELOPS LOWER CEILINGS OFF THE LAKE BY MORNING. WRF GOES-R
SUGGESTS SOME SCATTERING OUT EARLY BUT THEN BRINGS STRATO- CU BACK
IN OVERNIGHT. WILL CONTINUE WITH SC DECK OVERNIGHT GENERALLY
BROKEN. WILL GO SKC AT ZZV. SOME GRADIENT APPEARS TO KEEP UP
OVERNIGHT BUT GUSTS SHOULD DIMINISH. AS SUGGESTED BY HRRR WILL
BRING SOME LOWER STRATUS IN AROUND 09Z BUT WITH SOME GRADIENT
WILL NOT GO VERY LOW ON ANY BR. NORTHWEST FLOW TO CONTINUE ON
FRIDAY. COULD BE A SPRINKLE OR TWO AROUND AND WENT GENERALLY WITH
BKN SC DECK IN PA AND SCATTERED IN OH.
.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
FINALLY CYCLONIC FLOW DIMINISHED FRIDAY NIGHT AS HIGH PRESSURE
BUILDS INTO REGION. EXPECT VFR THROUGH SUNDAY MORNING. THEN NEXT
SYSTEM MOVES INTO AREA FOR THE REMAINDER OF SUNDAY INTO EARLY
MONDAY...BRIEF HIGH PRESSURE THROUGH MIDDAY MONDAY AND THEN ANOTHER
STORM SYSTEM AND ASSOCIATED FRONT THROUGH TUESDAY WITH SOME
RESTRICTIONS POSSIBLE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
721 PM EDT THU JUN 13 2013
.SYNOPSIS...
BEHIND LOW PRESSURE HEADING TOWARD THE EAST COAST...IT WILL BE
MUCH COOLER AND LESS HUMID TONIGHT INTO FRIDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
CANCELLED THE REMAINING FLOOD WATCH AS HEAVY RAIN HAS MOVED OUT OF
THE REGION AND NO LONGER POSES A FLOOD THREAT. ADJUSTED POPS FOR
NARROW BAND OF SHOWERS MOVING SOUTH ASSOCIATED WITH BACK END OF
LOW PRESSURE/ UPPER TROUGH AXIS. THESE SHOWERS SHOULD END BY EARLY
EVENING. PRESSURE GRADIENT BEHIND EXITING SURFACE LOW OVER EASTERN
PA WILL KEEP GUSTY WEST TO NORTHWEST WINDS THIS EVENING AND MUCH
COOLER TEMPERATURES.
FOR FRIDAY A SHORTWAVE ON THE BACKSIDE OF UPPER LEVEL SYSTEM WILL
BRING ENOUGH INSTABILITY FOR A LOW CHANCE OF SHOWERS IN THE
AFTERNOON...ESPECIALLY ALONG THE RIDGES. TEMPERATURES WILL BE
ABOUT 5 TO 8 DEGREES BELOW AVERAGE TONIGHT AND FRIDAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
SURFACE HIGH PRESSURE WILL KEEP THE REGION DRY FRIDAY NIGHT
THROUGH SATURDAY WITH TEMPERATURES RETURNING TO NEAR AVERAGE
SATURDAY AFTER A COOL START.
NEXT SHORTWAVE WILL BE RACING EAST LATER SATURDAY NIGHT WITH WARM
ADVECTION INCREASING CLOUDS AND SHOWER CHANCES BY DAYBREAK
SUNDAY. UPPER POPS TO LIKELY FOR SUNDAY AS MODELS IN GOOD
AGREEMENT ON DEEP MOISTURE AND LIFT AS WEAK FRONT CROSSES THE
REGION AND LOOKS TO STALL NEAR OF THE MASON DIXON LINE LATE DAY
SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A STNRY FNT NR THE UPR OH VLLY SUN NGT INTO MON NGT WL CONT
SHWR/TSTM CHCS. AN UPR LVL TROF AND CDFNT ARE EXP TO CROSS THE GT
LKS TUE WITH BETTER CHCS FOR SHWRS/TSTMS. HIGH PRES BLDS IN WITH
DRY WEA WED AND THU. OVERALL TEMPS SHOULD BE NR OR SLIGHTLY BLO
SEASONAL AVGS.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
LOWER CLOUDS ASSOCIATED WITH NE STORM SYSTEM TRYING TO LIFT ENE.
HOWEVER, BROADER CYCLONIC FLOW AS SYSTEM PULLS NE WILL BRING
CONTINUED LOWER LEVEL STRATCU MOISTURE PLUME FROM NORTH AND WITH
LAKE TRAJECTORY. HRRR SUGGESTING SOME CLEARING OVERNIGHT BUT EVEN
IT DEVELOPS LOWER CEILINGS OFF THE LAKE BY MORNING. WRF GOES-R
SUGGESTS SOME SCATTERING OUT EARLY BUT THEN BRINGS STRATO- CU BACK
IN OVERNIGHT. WILL CONTINUE WITH SC DECK OVERNIGHT GENERALLY
BROKEN. WILL GO SKC AT ZZV. SOME GRADIENT APPEARS TO KEEP UP
OVERNIGHT BUT GUSTS SHOULD DIMINISH. AS SUGGESTED BY HRRR WILL
BRING SOME LOWER STRATUS IN AROUND 09Z BUT WITH SOME GRADIENT
WILL NOT GO VERY LOW ON ANY BR. NORTHWEST FLOW TO CONTINUE ON
FRIDAY. COULD BE A SPRINKLE OR TWO AROUND AND WENT GENERALLY WITH
BKN SC DECK IN PA AND SCATTERED IN OH.
.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
FINALLY CYCLONIC FLOW DIMINISHED FRIDAY NIGHT AS HIGH PRESSURE
BUILDS INTO REGION. EXPECT VFR THROUGH SUNDAY MORNING. THEN NEXT
SYSTEM MOVES INTO AREA FOR THE REMAINDER OF SUNDAY INTO EARLY
MONDAY...BRIEF HIGH PRESSURE THROUGH MIDDAY MONDAY AND THEN ANOTHER
STORM SYSTEM AND ASSOCIATED FRONT THROUGH TUESDAY WITH SOME
RESTRICTIONS POSSIBLE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
457 PM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE ACROSS THE GREAT LAKES AND OHIO VALLEY
REGION THROUGH THURSDAY...FOLLOWED BY BUILDING HIGH PRESSURE LATE
FRIDAY AND SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
500 PM UPDATE...SCATTERED SHOWERS SPREADING SE ACROSS NW SECTIONS
CWA. CAP STILL HOLDING BUT RIGOROUS DEVELOPMENT WELL UPSTREAM IN
IL AND IA. 18Z HRRR DEVELOPS CONVECTION NW OH AND PUSHES SE TO
EDGE OF CWA BY 00Z. WILL CONTINUE TO CLOSELY MONITOR.
REST OF PREVIOUS DISCUSSION FOLLOWS...
CLOUDS FROM A DSPTD TSTM COMPLEX CONT TO STREAM INTO THE RGN.
VERY LITTLE OF WHAT IS ON RADAR IS REACHING THE GROUND. THE
ATMOSPHERE REMAINS CAPPED WITH WARMING AT H7 PER RECENT AIRCRAFT
SOUNDING AND MESO DATA. UPSTREAM SPECIAL 18Z SOUNDINGS SHOW INCRD
CAPPING WITH FURTHER WRM AIR ADVCTN AT H7. THIS IS SPPRTD BY LTL
IF ANY CU ON VSBL STLT. THINK THE LULL IN ACTIVITY WL PERSIST INTO
THE EVE.
STILL EXPTG A TSTM COMPLEX TO DVLP ACRS THE IL/WI/IA AREA AS THE
CAP WKNS AND A SHRTWV MOVES IN. THIS CNVCTN SHOULD MOVE EWD INTO
OUR AREA LATER TNGT. PWATS SHOULD BE INCRG...AND EXP GOOD DYNAMICS
TO SPREAD EWD WITH A DEEPENING SFC LOW AS WELL. SPEED SHEAR AND
ELEVATED INSTAB STILL PLENTY SUFFICIENT TO MAINTAIN TSTMS AS THEY
MOVE INTO THE RGN. HIGHEST CHC FOR SVR TSTMS SHOULD BE OFF TO OUR
WEST...BUT STILL A THREAT FOR SVR INTO OUR RGN WITH ANY COMPLEX
THAT MOVES IN. MOMENTUM AND CNVCTV COLD POOLING SHOULD RESULT IN
DAMAGING WNDS BEING THE MAIN THREAT. WL HAVE TO CLOSELY MONITOR
THIS SITUATION TNGT.
WITH INCRG PWATS AND DYNAMICS INTO THU MRNG...HAVE EXPANDED THE
FLASH FLOOD WATCH FOR THE FORECAST AREA. EXPTG 1-2...WITH LOCALLY
3 INCHES OF RAIN PSBL. FLASH FLOOD GUIDANCE NUMBERS SPPRT THIS ESP
IN URBAN AND FLOOD PRONE AREAS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
THE SFC LOW AND A CDFNT WL PUSH E OF THE AREA THU AFTN...BRINGING
A GRDL END TO THE SHWRS/TSTMS. LOCALLY HEAVY RAINFALL STILL PSBL
IN THE MRNG. BEST THREAT FOR ANY SVR WEA SHOULD GENLY BE TO OUR E.
A WK VORT MAXES DROPS SE ACRS THE AREA FRI SO ONLY MENTIONED SLGT
CHC POPS FOR SHWRS. HIGH PRES QUICKLY BLDS IN LTR FRI AND SAT WITH
CLRG CONDS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE LONG WAVE PATTERN LOOKS TO FAVOR TROUGHING OVER THE GREAT LAKES
AND NORTHEASTERN REGION OF THE COUNTRY THROUGH THE PERIOD WITH
SEVERAL ILL-TIMED SHORT WAVE SYSTEMS LIKELY TO EVOLVE IN THE
NORTHWESTERLY FLOW ALOFT. THIS WILL BRING CHANCES OF SHOWERS AND
THUNDERSTORMS THROUGH MOST OF THE EXTENDED FORECAST. THIS SHOULD
KEEP TEMPERATURES FROM REALLY GETTING TOO WARM DURING ANY PARTICULAR
PERIOD OF THE LONG TERM AT LEAST UNTIL MID-WEEK NEXT WEEK. BY THAT
TIME...LONG WAVE RIDGING SHOULD START TO EDGE FROM THE PLAINS TOWARD
THE WESTERN GREAT LAKES...BRINGING A GRADUAL END TO UNSETTLED
CONDITIONS OVER OUR REGION.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
GENERAL VFR IS EXPECTED INTO THE LATE AFTERNOON. LATEST MODEL
SOUNDINGS SHOW SOME CAPPING STILL TO OVERCOME...AND HI RES
MODELS SHOW SCT STORMS POSSIBLE LATE AFTERNOON BUT NOTHING
WIDESPREAD AND HAVE KEPT VCTS UNTIL NEAR SUNSET.
SHOWERS/THUNDERSTORMS BECOME LIKELY 01-03Z WEST AND 04-06Z EAST AS
SURFACE LOW GAINS STRENGTH OVER THE LOWER OHIO VALLEY...WITH
PREVAILING TSRA CONTINUED UNTIL 08-09Z. LOCAL IFR CONDITIONS WILL BE
POSSIBLE IN THE HEAVIEST CELLS. TIMING WILL LIKELY NEED TO BE
ADJUSTED BASED ON DEVELOPMENT OF ANY CONVECTIVE COMPLEX. LOW
PRESSURE SYSTEM WILL THEN WRAP UP AS IT CROSSES THE RIDGES THURSDAY
MORNING WITH COLD FRONT PUSHING EAST ACROSS THE REGION MID MORNING
TO EARLY AFTERNOON. LOW LEVEL WIND SHEAR MAINTAINED FOR THE
OVERNIGHT HOURS AS LOW LEVEL JET WILL BE RIDING OVER DEVELOPING
INVERSION OVERNIGHT. RESTRICTIONS IN SHOWERS WILL END NORTHWEST TO
SOUTHEAST THURSDAY AS COLD FRONT SWEEPS EAST.
.OUTLOOK.../THURSDAY NIGHT THROUGH SUNDAY/...
HIGH PRES WL RTN VFR TO REGIONAL PORTS FOR FRI AND SAT. PCPN AND
RESTRICTION CHCS WL INCRS AGAIN SUNDAY INTO MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLASH FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR MDZ001.
OH...FLASH FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR OHZ039>041-048>050-057>059-068-069.
PA...FLASH FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR PAZ007>009-013>016-020>023-029-031-073>076.
WV...FLASH FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR WVZ001>004-012-021>023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
700 PM EDT WED JUN 12 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 339 PM EDT WED JUN 12 2013
STRONG LOW PRESSURE SYSTEM WILL BRING THUNDERSTORMS... SOME POSSIBLY
SEVERE WITH HEAVY RAINFALL OVERNIGHT CAUSING LOCAL FLOODING. SOME
CLEARING
BY THURSDAY AFTERNOON CONTINUING INTO FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 339 PM EDT WED JUN 12 2013
LATEST MODEL TRENDS SUGGEST RISK OF SEVERE THUNDERSTORMS EARLY TO
MID EVENING. THERE IS A THREAT OF HEAVY RAINFALL SOUTH OF
INTERSTATE 96.
WE EXPECT A LOW LEVEL JET FOCUSED SOUTH OF I-80 INTO THE EVENING
THAT WILL RESULT IN THE STRONGEST THUNDERSTORMS TRACKING SOUTH
INTO I-94 INTO THE EARLY EVENING. THE STRONG UPPER DYNAMICS WILL
DEVELOP THE DIGGING SHORTWAVE WILL RESULT IN A TROWAL ON THE NORTH
SIDE OF THE SYSTEM OVERNIGHT THAT WILL RESULT IN A BAND OF
PERSISTENT HEAVY RAINFALL. WE EXPECT THUNDERSTORM COMPLEX TO
DEVELOP WEST OF CHICAGO BY 6 PM THEN TRACK EAST SOUTHEAST ALONG
THE MICHIGAN INDIANA BORDER DURING THE EARLY EVENING. RAINFALL
AMOUNTS OF 2 TO 3 INCHES ARE SUGGESTED BY THE HRRR... RAP AND SPC
WRF. THIS RAINFALL IS INDEPENDENT OF THE THUNDERSTORM COMPLEX THIS
EVENING.
THIS SYSTEM SHOULD EXIT THE AREA BY THE MID MORNING HOURS
THURSDAY. A TRAILING SHORTWAVE AND SECONDARY COLD FRONT DIVING
SOUTH ON THE NORTHERN STREAM JET WILL INTERACT WITH THE LAKE
MICHIGAN AND LAKE HURON LAKE BREEZE THURSDAY AFTERNOON TO CREATE
INSTABILITY SHOWERS.
RIDGING WILL MOVE INTO THE AREA THURSDAY NIGHT INTO FRIDAY
BRINGING CLEARING SKIES AND COOLER TEMPERATURES.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 339 PM EDT WED JUN 12 2013
A COUPLE OF LOW PRESSURE SYSTEMS WILL BRING POTENTIAL FOR SCATTERED
SHOWERS AND THUNDERSTORMS FROM LATE SATURDAY THROUGH SUNDAY AND
MONDAY. BEYOND THAT A CONSENSUS OF LATEST MEDIUM RANGE GUIDANCE
INCLUDING THE 12Z GFS AND 00Z ECMWF SUGGESTS HIGH PRESSURE SHOULD
BUILD IN AND BRING FAIR WX FOR THE MIDDLE PORTION OF NEXT WEEK.
TEMPS SHOULD AVERAGE RATHER CLOSE TO NORMAL THROUGH THE LONG RANGE
FORECAST PERIOD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY)
ISSUED AT 700 PM EDT WED JUN 12 2013
PRIMARY AVIATION CONCERN CONTINUES TO BE ON SEVERE THUNDERSTORMS
THAT WILL LIKELY IMPACT KAZO... KBTL AND KJXN DURING THE MID TO LATE
EVENING HOURS. A FAST MOVING COMPLEX OF SEVERE STORMS IS LIKELY TO
IMPACT THESE TERMINALS FROM 02Z THROUGH 06Z WITH POTENTIAL FOR VERY
SIGNIFICANT WIND GUSTS IN ADDITION TO FREQUENT LIGHTNING... HEAVY
RAIN AND HAIL.
AT THIS TIME WE ARE FORECASTING WIND GUSTS TO POTENTIALLY REACH 45
KTS IN THE STORMS BUT POTENTIALLY WIND GUSTS COULD BE EVEN HIGHER IF
AN ORGANIZED BOW ECHO MOVES ACROSS THE I-94 CORRIDOR LATE THIS
EVENING.
SHOWERS AND THUNDERSTORMS WILL ALSO LIKELY IMPACT THE TERMINALS
FURTHER NORTH (KMKG... KGRR AND KLAN) FROM MID TO LATE EVENING BUT
THOSE STORMS ARE NOT LIKELY TO BE SEVERE.
NORTHERLY WINDS WILL DEVELOP LATE TONIGHT IN THE WAKE OF THE STORMS
WITH MVFR CEILINGS AND POSSIBLY VSBY/S (FOG) DEVELOPING. CONDITIONS
WILL IMPROVE TO VFR BY MID TO LATE MORNING THURSDAY WITH NNW WINDS
GUSTING UP TO AROUND 20 KTS AND JUST SOME SCT HIGH CLOUD COVER.
&&
.MARINE...
ISSUED AT 339 PM EDT WED JUN 12 2013
WE ISSUED A SMALL CRAFT ADVISORY TONIGHT THROUGH THURSDAY NIGHT
DUE TO 20 TO 25 KNOT NORTH WINDS BEHIND THE SYSTEM WITH STRONG
COLD AIR ADVECTION.
WE ADDED FOG TO THE NEARSHORE WATERS BASED ON WEB CAMS AND
DEW POINTS IN THE UPPER 60S WHICH IS HIGHER THAN THE MID 50S LAKE
TEMPERATURES. ONCE WIND SHIFTS MID EVENING TO THE NORTH AND
BRINGS DRIER AIR IN THE FOG DISPERSE.
&&
.HYDROLOGY...
ISSUED AT 339 PM EDT WED JUN 12 2013
THERE IS A THREAT FOR FLASH FLOODING TONIGHT AS THE MODELS SUGGEST
2 TO 3 INCHES OF RAIN ALONG THE I-94 CORRIDOR. THIS IS THE RESULT
OF TROWAL DEVELOPING ON THE NORTH SIDE OF THE INTENSIFYING SURFACE
LOW. THE LATEST FLASH FLOODING GUIDANCE FROM THE NCRFC SUGGESTS
RAINFALL AMOUNTS OF MORE THAN 2 INCHES IN 6 HOURS WILL GENERATE
FLASH FLOODING OVER THE SOUTHERN TWO ROWS OF COUNTIES.
PRECIPITABLE WATER VALUES FORECAST 1.75 INCHES THIS EVENING. THIS
IS BETWEEN 2 AND 3 STANDARD DEVIATIONS FROM NORMAL. WHEN YOU ADD
THAT TO THE DYNAMICS FORECAST TO THE AREA RESULTS IN A FLASH FLOOD
THREAT SO WE ISSUED A FLASH FLOOD WATCH OVER THE SOUTHERN TWO ROWS
OF COUNTIES WHERE THE HEAVIEST RAINFALL WILL OCCUR.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FLASH FLOOD WATCH FROM 8 PM EDT THIS EVENING THROUGH THURSDAY
MORNING FOR MIZ064>067-071>074.
LM...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 AM EDT FRIDAY
FOR LMZ844>849.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
342 PM EDT WED JUN 12 2013
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 339 PM EDT WED JUN 12 2013
STRONG LOW PRESSURE SYSTEM WILL BRING THUNDERSTORMS... SOME POSSIBLY
SEVERE WITH HEAVY RAINFALL OVERNIGHT CAUSING LOCAL FLOODING. SOME CLEARING
BY THURSDAY AFTERNOON CONTINUING INTO FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 339 PM EDT WED JUN 12 2013
LATEST MODEL TRENDS SUGGEST RISK OF SEVERE THUNDERSTORMS EARLY TO
MID EVENING. THERE IS A THREAT OF HEAVY RAINFALL SOUTH OF
INTERSTATE 96.
WE EXPECT A LOW LEVEL JET FOCUSED SOUTH OF I-80 INTO THE EVENING
THAT WILL RESULT IN THE STRONGEST THUNDERSTORMS TRACKING SOUTH
INTO I-94 INTO THE EARLY EVENING. THE STRONG UPPER DYNAMICS WILL
DEVELOP THE DIGGING SHORTWAVE WILL RESULT IN A TROWAL ON THE NORTH
SIDE OF THE SYSTEM OVERNIGHT THAT WILL RESULT IN A BAND OF
PERSISTENT HEAVY RAINFALL. WE EXPECT THUNDERSTORM COMPLEX TO
DEVELOP WEST OF CHICAGO BY 6 PM THEN TRACK EAST SOUTHEAST ALONG
THE MICHIGAN INDIANA BORDER DURING THE EARLY EVENING. RAINFALL
AMOUNTS OF 2 TO 3 INCHES ARE SUGGESTED BY THE HRRR... RAP AND SPC
WRF. THIS RAINFALL IS INDEPENDENT OF THE THUNDERSTORM COMPLEX THIS
EVENING.
THIS SYSTEM SHOULD EXIT THE AREA BY THE MID MORNING HOURS
THURSDAY. A TRAILING SHORTWAVE AND SECONDARY COLD FRONT DIVING
SOUTH ON THE NORTHERN STREAM JET WILL INTERACT WITH THE LAKE
MICHIGAN AND LAKE HURON LAKE BREEZE THURSDAY AFTERNOON TO CREATE
INSTABILITY SHOWERS.
RIDGING WILL MOVE INTO THE AREA THURSDAY NIGHT INTO FRIDAY
BRINGING CLEARING SKIES AND COOLER TEMPERATURES.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 339 PM EDT WED JUN 12 2013
A COUPLE OF LOW PRESSURE SYSTEMS WILL BRING POTENTIAL FOR SCATTERED
SHOWERS AND THUNDERSTORMS FROM LATE SATURDAY THROUGH SUNDAY AND
MONDAY. BEYOND THAT A CONSENSUS OF LATEST MEDIUM RANGE GUIDANCE
INCLUDING THE 12Z GFS AND 00Z ECMWF SUGGESTS HIGH PRESSURE SHOULD
BUILD IN AND BRING FAIR WX FOR THE MIDDLE PORTION OF NEXT WEEK.
TEMPS SHOULD AVERAGE RATHER CLOSE TO NORMAL THROUGH THE LONG RANGE
FORECAST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 100 PM EDT WED JUN 12 2013
VFR CONDITIONS SHOULD CONTINUE AT ALL THE TERMINALS THIS AFTERNOON
WITH FAIRLY EXTENSIVE MID CLOUD COVER AND A FEW SHOWERS.
PRIMARY AVIATION CONCERN IS ON SEVERE THUNDERSTORMS THAT WILL LIKELY
IMPACT KAZO... KBTL AND KJXN DURING THE MID TO LATE EVENING HOURS. A
FAST MOVING COMPLEX OF SEVERE STORMS IS LIKELY TO IMPACT THESE
TERMINALS FROM 01Z THROUGH 06Z WITH POTENTIAL FOR VERY SIGNIFICANT
WIND GUSTS IN ADDITION TO FREQUENT LIGHTNING... HEAVY RAIN AND HAIL.
NORTHERLY WINDS WILL DEVELOP TONIGHT IN THE WAKE OF THE STORMS WITH
MVFR CEILINGS AND POSSIBLY VSBY/S (FOG) DEVELOPING.
&&
.MARINE...
ISSUED AT 339 PM EDT WED JUN 12 2013
WE ISSUED A SMALL CRAFT ADVISORY TONIGHT THROUGH THURSDAY NIGHT
DUE TO 20 TO 25 KNOT NORTH WINDS BEHIND THE SYSTEM WITH STRONG
COLD AIR ADVECTION.
WE ADDED FOG TO THE NEARSHORE WATERS BASED ON WEB CAMS AND
DEW POINTS IN THE UPPER 60S WHICH IS HIGHER THAN THE MID 50S LAKE
TEMPERATURES. ONCE WIND SHIFTS MID EVENING TO THE NORTH AND
BRINGS DRIER AIR IN THE FOG DISPERSE.
&&
.HYDROLOGY...
ISSUED AT 339 PM EDT WED JUN 12 2013
THERE IS A THREAT FOR FLASH FLOODING TONIGHT AS THE MODELS SUGGEST
2 TO 3 INCHES OF RAIN ALONG THE I-94 CORRIDOR. THIS IS THE RESULT
OF TROWAL DEVELOPING ON THE NORTH SIDE OF THE INTENSIFYING SURFACE
LOW. THE LATEST FLASH FLOODING GUIDANCE FROM THE NCRFC SUGGESTS
RAINFALL AMOUNTS OF MORE THAN 2 INCHES IN 6 HOURS WILL GENERATE
FLASH FLOODING OVER THE SOUTHERN TWO ROWS OF COUNTIES.
PRECIPITABLE WATER VALUES FORECAST 1.75 INCHES THIS EVENING. THIS
IS BETWEEN 2 AND 3 STANDARD DEVIATIONS FROM NORMAL. WHEN YOU ADD
THAT TO THE DYNAMICS FORECAST TO THE AREA RESULTS IN A FLASH FLOOD
THREAT SO WE ISSUED A FLASH FLOOD WATCH OVER THE SOUTHERN TWO ROWS
OF COUNTIES WHERE THE HEAVIEST RAINFALL WILL OCCUR.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FLASH FLOOD WATCH FROM 8 PM EDT THIS EVENING THROUGH THURSDAY
MORNING FOR MIZ064>067-071>074.
LM...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 AM EDT FRIDAY
FOR LMZ844>849.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
204 PM EDT WED JUN 12 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 330 AM EDT WED JUN 12 2013
AS LOW PRESSURE MOVES EAST FROM THE PLAINS TOWARD NORTHERN INDIANA
TODAY SHOWERS AND THUNDERSTORMS WILL DEVELOP. SOME OF THE STORMS
COULD BE STRONG TO SEVERE ESPECIALLY SOUTH OF I-94 WITH HIGH WINDS
THE MAIN THREAT. HEAVY RAIN WILL BE POSSIBLE THIS AFTERNOON AND
EVENING TOO SOUTH OF I-96. QUIETER WEATHER WILL RETURN THURSDAY
THROUGH SATURDAY AS THE LOW MOVES EAST AND NORTH WINDS ADVECT DRIER
AIR INTO LOWER MICHIGAN.
&&
.UPDATE...
ISSUED AT 203 PM EDT WED JUN 12 2013
I HAVE ISSUED A FLASH FLOOD WATCH BASED ON THE POTENTIAL FOR HEAVY
RAIN WITH THE TROWAL FEATURE NORTH OF THE MAIN UPPER LEVEL WAVE
AS IT COMES THROUGH TONIGHT. THE SPC SREF...THE 15Z HRRR AND THE
15Z ESRL RAP MODELS ALL SHOW 2 TO 3 INCHES OF RAIN TONIGHT JUST
SOUTH OF INTERSTATE 96. GIVEN THE CONVECTIVE NATURE OF THE EVENT
IT WOULD SEEM REASONABLE THAT FLASH FLOODING IS POSSIBLE IN THIS
AREA.
IT STILL LOOKS LIKE THE STRONG THUNDERSTORMS WILL CROSS OUR AREA
AFTER 10 PM TONIGHT AND THOSE STORMS WOULD SEEM TO WANT TO TRACK
SOUTH OF INTERSTATE 94. STILL THERE WOULD BE A LARGE AREA OF HEAVY
RAIN NORTH OF THAT... MAYBE AS FAR NORTH AS INTERSTATE 96.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
FORECAST CONCERNS DEAL WITH CONVECTIVE TRENDS THIS MORNING THROUGH
THIS EVENING.
LATEST REGIONAL RADAR SHOWS THAT STORMS HAVE FIRED AS EXPECTED IN
NORTHEAST NEBRASKA ON THE NOSE OF A STRONG LLJ. THESE STORMS HAVE
MOVED INTO NW IOWA. A BIT FARTHER NORTH OVER SOUTH DAKOTA ANOTHER
AREA OF STORMS IS MOVE EWD. THESE ARE ASSOCIATED WITH A SHORT WAVE
MOVING ACROSS THE NRN PLAINS. SHORT RANGE MODELS MOVE THIS SHORT
WAVE SEWD TOWARD CHICAGO BY THIS AFTERNOON AT THE SAME TIME THE SFC
LOW IN SRN NEBRASKA IS MOVING ENEWD. HRRR SHOWS BOTH CLUSTERS OF
STORMS WEAKENING AS THEY MOVE EAST WITH THE IOWA CONVECTION MOVING
TO THE WRN CWA BY NOON OR SO AS MOSTLY SHOWERS.
CONVECTION REDEVELOPS OVER NW IOWA BY EARLY AFTERNOON AS STRONG
DYNAMICS TAKE SHAPE. SBCAPE AROUND 3K J/KG COUPLED WITH STRONG
MOISTURE CONVERGENCE...60-70KTS BULK SHEAR AND LIFT FROM THE
APPROACHING SHORT WAVE SHOULD RESULT IN STRONG TO SEVERE STORMS
DEVELOPING OVER ILLINOIS AND MOVING ESE TOWARD THE SRN CWA. A 50KT
MID LEVEL JET WILL PUSH THE STORMS EWD...PERHAPS AS A DERECHO. CAN/T
ARGUE TOO MUCH WITH THE POSITION OF THE DAY ONE SLIGHT AND MODERATE
RISK AREAS. THIS ISN/T A SLAM DUNK BY ANY MEANS BUT THE HIGHEST
THREAT FOR STRONG/SVR STORMS WILL BE SOUTH OF A MUSKEGON TO LANSING
LINE. LATEST NAM ALSO PUSHES THE WARM FRONT INTO THE SRN CWA THIS
AFTERNOON. SO...WITH THE WARM FRONT IN PLACE WE CAN/T RULE OUT A
TORNADO EITHER.
THE SVR THREAT WILL END THIS EVENING AS THE LOW MOVES BY TO THE
SOUTH AND QUIETER WEATHER WILL RETURN THURSDAY AND FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
UPPER RIDGING WILL EXTEND FROM THE GULF COAST NORTH INTO THE UPPER
MID WEST FRIDAY NIGHT. THE RIDGING WILL BE FLATTENED THROUGH THE
LONG TERM AS A SERIES OF SHORTWAVE/S CREST THE RIDGE AND MOVE
THROUGH THE GREAT LAKES REGION. THE FIRST OF WHICH MOVES INTO THE
AREA ON SATURDAY. THE SECOND AND MORE SUBSTANTIAL WAVE DIGS INTO THE
GREAT LAKES REGION SUNDAY INTO MONDAY.
AT THE SURFACE RIDGING WILL BE IN PLACE FRIDAY NIGHT AND BRING DRY
WEATHER. THE HIGH SLIPS EAST QUICKLY ON SATURDAY WHICH SHOULD ALLOW
CHANCES FOR SHOWERS AND STORMS DURING THE AFTERNOON AHEAD OF THE
UPPER SHORTWAVE. THE CHANCES WILL CONTINUE INTO SATURDAY NIGHT AS A
WAVE OF LOW PRESSURE SLIDES THROUGH THE AREA AT THE SURFACE.
SUNDAY INTO MONDAY CHANCES FOR SHOWERS AND STORMS WILL CONTINUE AS
THE SECOND MORE POTENT UPPER TROUGH DIGS INTO THE GREAT LAKES.
SURFACE FEATURES ARE BIT MORE HARD TO DISCERN IN THIS TIME FRAME AS
THE GFS IS FURTHER NORTH AND DEEPER WITH THE SURFACE WAVE. FOLLOWED
THE GFS CLOSER HERE AS IT MAKES MORE SENSE TO HAVE A DEEPER FARTHER
NORTH WAVE GIVEN THE UPPER PATTERN. WE LOOK TO DRY OUT MONDAY NIGHT
INTO TUESDAY AS HIGH PRESSURE BUILDS IN.
TEMPERATURES THROUGH THE PERIOD SHOULD BE SEASONABLE DESPITE THE
RIDGING DAMPENING OUT. HEIGHTS ARE STILL FAIRLY HIGH AND 850MB TEMPS
ARE FORECAST TO BE IN THE TEENS C. HIGHS SHOULD BE IN THE UPPER 70S
TO AROUND 80 EACH DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 100 PM EDT WED JUN 12 2013
VFR CONDITIONS SHOULD CONTINUE AT ALL THE TERMINALS THIS AFTERNOON
WITH FAIRLY EXTENSIVE MID CLOUD COVER AND A FEW SHOWERS.
PRIMARY AVIATION CONCERN IS ON SEVERE THUNDERSTORMS THAT WILL LIKELY
IMPACT KAZO... KBTL AND KJXN DURING THE MID TO LATE EVENING HOURS. A
FAST MOVING COMPLEX OF SEVERE STORMS IS LIKELY TO IMPACT THESE
TERMINALS FROM 01Z THROUGH 06Z WITH POTENTIAL FOR VERY SIGNIFICANT
WIND GUSTS IN ADDITION TO FREQUENT LIGHTNING... HEAVY RAIN AND HAIL.
NORTHERLY WINDS WILL DEVELOP TONIGHT IN THE WAKE OF THE STORMS WITH
MVFR CEILINGS AND POSSIBLY VSBY/S (FOG) DEVELOPING.
&&
.MARINE...
ISSUED AT 330 AM EDT WED JUN 12 2013
FAIRLY LIGHT WINDS WILL CONTINUE OVER THE LAKE RESULTING IN LOW WAVE
HEIGHTS. PATCHY DENSE FOG IS POSSIBLE DUE TO HIGH DEWPOINTS OVER THE
COLDER WATER SFC. NORTH WINDS WILL DEVELOP THURSDAY AND A SMALL
CRAFT ADVISORY MAY BE NEEDED.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT WED JUN 12 2013
THE MAIN PERIOD OF CONCERN IS THIS AFTERNOON AND EVENING. HEAVY
RAINFALL WILL BE POSSIBLE ACROSS THE SRN HALF OF THE CWA DURING THIS
TIME. AN INCH TO TWO INCHES SEEMS PLAUSIBLE ESPECIALLY SOUTH OF
I-94. THIS MAY LEAD TO LOCALIZED FLOODING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FLASH FLOOD WATCH FROM 8 PM EDT THIS EVENING THROUGH THURSDAY
MORNING FOR MIZ064>067-071>074.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...LAURENS
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
100 PM EDT WED JUN 12 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 330 AM EDT WED JUN 12 2013
AS LOW PRESSURE MOVES EAST FROM THE PLAINS TOWARD NORTHERN INDIANA
TODAY SHOWERS AND THUNDERSTORMS WILL DEVELOP. SOME OF THE STORMS
COULD BE STRONG TO SEVERE ESPECIALLY SOUTH OF I-94 WITH HIGH WINDS
THE MAIN THREAT. HEAVY RAIN WILL BE POSSIBLE THIS AFTERNOON AND
EVENING TOO SOUTH OF I-96. QUIETER WEATHER WILL RETURN THURSDAY
THROUGH SATURDAY AS THE LOW MOVES EAST AND NORTH WINDS ADVECT DRIER
AIR INTO LOWER MICHIGAN.
&&
.UPDATE...
ISSUED AT 1209 PM EDT WED JUN 12 2013
WE ADDED SEVERE WEATHER TO OUR GRIDS TO MATCH THE THIRTY PERCENT
AREA OF THE LATEST SPC OUTLOOK. WE DID THIS FROM 5PM TO 11PM
BECAUSE THE SPC MODELS WERE SHOWING THE HIGHEST PROBABILITY DURING
THAT TIME FRAME.
AN AREA OF SHOWERS OVER EASTERN WISCONSIN TO SOUTHERN LAKE MICHIGAN
IS MOVING INTO THE CWA OVER THE NEXT FEW HOURS. IN SPITE OF THE
INCREASING INSTABILITY WE DO NOT EXPECT STRONG THUNDERSTORM
DEVELOPMENT AS THERE IS TOO MUCH CONVECTIVE INHIBITION AND MID
LEVEL DRY AIR.
UPDATE ISSUED AT 1043 AM EDT WED JUN 12 2013
MY CURRENT THINKING IS THE BEST THREAT FOR SEVERE STORMS WILL BE
THIS EVENING INTO EARLY TONIGHT. THE DENSE MID AND HIGH CLOUD
COVER OVER MN/WI/LWR MI WILL CAUSE THE BEST DESTABILIZATION TO BE
WELL SOUTH OF OUR AREA THIS AFTERNOON. SO... THE STRONGEST
THUNDERSTORMS WILL BE ASSOCIATED WITH THE MAIN UPPER LEVEL WAVE
MOVING THROUGH THIS EVENING. THIS IDEA IS SUPPORTED BY THE LATEST
12Z NAM...12Z HRRR...00Z SPC WRF...12 RAP MODELS.
THE BEST FORCING (MOISTURE TRANSPORT VECTORS 1000/850...LOW LEVEL
JET AND THERMAL GRADIENT...HIGHEST MIXED LAYER CAPE) ARE ALL WELL
SOUTH OF INTERSTATE 94 AND ACTUALLY NEAR AND SOUTH OF INTERSTATE
80 AS THE UPPER WAVE MOVES THROUGH EARLY TONIGHT. WE SHOULD SEE
SOME CONVECTION OVER OUR SRN ONE OR TWO ROWS OF COUNTIES MID
EVENING AS THE WAVE MOVES IN. DEFORMATION ZONE RAIN WILL FOLLOW
DURING THE OVERNIGHT HOURS. THE HEAVIEST OF THAT WILL BE NEAR AND
SOUTH OF INTERSTATE 94.
THERE IS A CONVECTIVE COMPLEX OVER E CNTL MN AT 10 AM HEADING
EAST. THAT IS ON THE TAIL OF THE PV MAX ASSOCIATED WITH THE
CONVECTION THAT CROSSED MN AND WI EARLIER AND HAS SINCE DIED. THAT
PV MAX MOVES THROUGH OUR CNTL CWA THIS AFTERNOON. I BELIEVE THAT
WILL BE THE FOCUS FOR OUR AFTERNOON CONVECTION. THE INSTABILITY IS
MARGINAL (LOOKING AT RAP SOUNDING THIS AFTERNOON) FOR THIS
CONVECTION SO I DO NOT BELIEVE THIS WILL BE SEVERE... MOSTLY JUST
GENERIC THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
FORECAST CONCERNS DEAL WITH CONVECTIVE TRENDS THIS MORNING THROUGH
THIS EVENING.
LATEST REGIONAL RADAR SHOWS THAT STORMS HAVE FIRED AS EXPECTED IN
NORTHEAST NEBRASKA ON THE NOSE OF A STRONG LLJ. THESE STORMS HAVE
MOVED INTO NW IOWA. A BIT FARTHER NORTH OVER SOUTH DAKOTA ANOTHER
AREA OF STORMS IS MOVE EWD. THESE ARE ASSOCIATED WITH A SHORT WAVE
MOVING ACROSS THE NRN PLAINS. SHORT RANGE MODELS MOVE THIS SHORT
WAVE SEWD TOWARD CHICAGO BY THIS AFTERNOON AT THE SAME TIME THE SFC
LOW IN SRN NEBRASKA IS MOVING ENEWD. HRRR SHOWS BOTH CLUSTERS OF
STORMS WEAKENING AS THEY MOVE EAST WITH THE IOWA CONVECTION MOVING
TO THE WRN CWA BY NOON OR SO AS MOSTLY SHOWERS.
CONVECTION REDEVELOPS OVER NW IOWA BY EARLY AFTERNOON AS STRONG
DYNAMICS TAKE SHAPE. SBCAPE AROUND 3K J/KG COUPLED WITH STRONG
MOISTURE CONVERGENCE...60-70KTS BULK SHEAR AND LIFT FROM THE
APPROACHING SHORT WAVE SHOULD RESULT IN STRONG TO SEVERE STORMS
DEVELOPING OVER ILLINOIS AND MOVING ESE TOWARD THE SRN CWA. A 50KT
MID LEVEL JET WILL PUSH THE STORMS EWD...PERHAPS AS A DERECHO. CAN/T
ARGUE TOO MUCH WITH THE POSITION OF THE DAY ONE SLIGHT AND MODERATE
RISK AREAS. THIS ISN/T A SLAM DUNK BY ANY MEANS BUT THE HIGHEST
THREAT FOR STRONG/SVR STORMS WILL BE SOUTH OF A MUSKEGON TO LANSING
LINE. LATEST NAM ALSO PUSHES THE WARM FRONT INTO THE SRN CWA THIS
AFTERNOON. SO...WITH THE WARM FRONT IN PLACE WE CAN/T RULE OUT A
TORNADO EITHER.
THE SVR THREAT WILL END THIS EVENING AS THE LOW MOVES BY TO THE
SOUTH AND QUIETER WEATHER WILL RETURN THURSDAY AND FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
UPPER RIDGING WILL EXTEND FROM THE GULF COAST NORTH INTO THE UPPER
MID WEST FRIDAY NIGHT. THE RIDGING WILL BE FLATTENED THROUGH THE
LONG TERM AS A SERIES OF SHORTWAVE/S CREST THE RIDGE AND MOVE
THROUGH THE GREAT LAKES REGION. THE FIRST OF WHICH MOVES INTO THE
AREA ON SATURDAY. THE SECOND AND MORE SUBSTANTIAL WAVE DIGS INTO THE
GREAT LAKES REGION SUNDAY INTO MONDAY.
AT THE SURFACE RIDGING WILL BE IN PLACE FRIDAY NIGHT AND BRING DRY
WEATHER. THE HIGH SLIPS EAST QUICKLY ON SATURDAY WHICH SHOULD ALLOW
CHANCES FOR SHOWERS AND STORMS DURING THE AFTERNOON AHEAD OF THE
UPPER SHORTWAVE. THE CHANCES WILL CONTINUE INTO SATURDAY NIGHT AS A
WAVE OF LOW PRESSURE SLIDES THROUGH THE AREA AT THE SURFACE.
SUNDAY INTO MONDAY CHANCES FOR SHOWERS AND STORMS WILL CONTINUE AS
THE SECOND MORE POTENT UPPER TROUGH DIGS INTO THE GREAT LAKES.
SURFACE FEATURES ARE BIT MORE HARD TO DISCERN IN THIS TIME FRAME AS
THE GFS IS FURTHER NORTH AND DEEPER WITH THE SURFACE WAVE. FOLLOWED
THE GFS CLOSER HERE AS IT MAKES MORE SENSE TO HAVE A DEEPER FARTHER
NORTH WAVE GIVEN THE UPPER PATTERN. WE LOOK TO DRY OUT MONDAY NIGHT
INTO TUESDAY AS HIGH PRESSURE BUILDS IN.
TEMPERATURES THROUGH THE PERIOD SHOULD BE SEASONABLE DESPITE THE
RIDGING DAMPENING OUT. HEIGHTS ARE STILL FAIRLY HIGH AND 850MB TEMPS
ARE FORECAST TO BE IN THE TEENS C. HIGHS SHOULD BE IN THE UPPER 70S
TO AROUND 80 EACH DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 100 PM EDT WED JUN 12 2013
VFR CONDITIONS SHOULD CONTINUE AT ALL THE TERMINALS THIS AFTERNOON
WITH FAIRLY EXTENSIVE MID CLOUD COVER AND A FEW SHOWERS.
PRIMARY AVIATION CONCERN IS ON SEVERE THUNDERSTORMS THAT WILL LIKELY
IMPACT KAZO... KBTL AND KJXN DURING THE MID TO LATE EVENING HOURS. A
FAST MOVING COMPLEX OF SEVERE STORMS IS LIKELY TO IMPACT THESE
TERMINALS FROM 01Z THROUGH 06Z WITH POTENTIAL FOR VERY SIGNIFICANT
WIND GUSTS IN ADDITION TO FREQUENT LIGHTNING... HEAVY RAIN AND HAIL.
NORTHERLY WINDS WILL DEVELOP TONIGHT IN THE WAKE OF THE STORMS WITH
MVFR CEILINGS AND POSSIBLY VSBY/S (FOG) DEVELOPING.
&&
.MARINE...
ISSUED AT 330 AM EDT WED JUN 12 2013
FAIRLY LIGHT WINDS WILL CONTINUE OVER THE LAKE RESULTING IN LOW WAVE
HEIGHTS. PATCHY DENSE FOG IS POSSIBLE DUE TO HIGH DEWPOINTS OVER THE
COLDER WATER SFC. NORTH WINDS WILL DEVELOP THURSDAY AND A SMALL
CRAFT ADVISORY MAY BE NEEDED.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT WED JUN 12 2013
THE MAIN PERIOD OF CONCERN IS THIS AFTERNOON AND EVENING. HEAVY
RAINFALL WILL BE POSSIBLE ACROSS THE SRN HALF OF THE CWA DURING THIS
TIME. AN INCH TO TWO INCHES SEEMS PLAUSIBLE ESPECIALLY SOUTH OF
I-94. THIS MAY LEAD TO LOCALIZED FLOODING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...LAURENS
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1209 PM EDT WED JUN 12 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 330 AM EDT WED JUN 12 2013
AS LOW PRESSURE MOVES EAST FROM THE PLAINS TOWARD NORTHERN INDIANA
TODAY SHOWERS AND THUNDERSTORMS WILL DEVELOP. SOME OF THE STORMS
COULD BE STRONG TO SEVERE ESPECIALLY SOUTH OF I-94 WITH HIGH WINDS
THE MAIN THREAT. HEAVY RAIN WILL BE POSSIBLE THIS AFTERNOON AND
EVENING TOO SOUTH OF I-96. QUIETER WEATHER WILL RETURN THURSDAY
THROUGH SATURDAY AS THE LOW MOVES EAST AND NORTH WINDS ADVECT DRIER
AIR INTO LOWER MICHIGAN.
&&
.UPDATE...
ISSUED AT 1209 PM EDT WED JUN 12 2013
WE ADDED SEVERE WEATHER TO OUR GRIDS TO MATCH THE THIRTY PERCENT
AREA OF THE LATEST SPC OUTLOOK. WE DID THIS FROM 5PM TO 11PM
BECAUSE THE SPC MODELS WERE SHOWING THE HIGHEST PROBABILITY DURING
THAT TIME FRAME.
AN AREA OF SHOWERS OVER EASTERN WISCONSIN TO SOUTHERN LAKE MICHIGAN
IS MOVING INTO THE CWA OVER THE NEXT FEW HOURS. IN SPITE OF THE
INCREASING INSTABILITY WE DO NOT EXPECT STRONG THUNDERSTORM
DEVELOPMENT AS THERE IS TOO MUCH CONVECTIVE INHIBITION AND MID
LEVEL DRY AIR.
UPDATE ISSUED AT 1043 AM EDT WED JUN 12 2013
MY CURRENT THINKING IS THE BEST THREAT FOR SEVERE STORMS WILL BE
THIS EVENING INTO EARLY TONIGHT. THE DENSE MID AND HIGH CLOUD
COVER OVER MN/WI/LWR MI WILL CAUSE THE BEST DESTABILIZATION TO BE
WELL SOUTH OF OUR AREA THIS AFTERNOON. SO... THE STRONGEST
THUNDERSTORMS WILL BE ASSOCIATED WITH THE MAIN UPPER LEVEL WAVE
MOVING THROUGH THIS EVENING. THIS IDEA IS SUPPORTED BY THE LATEST
12Z NAM...12Z HRRR...00Z SPC WRF...12 RAP MODELS.
THE BEST FORCING (MOISTURE TRANSPORT VECTORS 1000/850...LOW LEVEL
JET AND THERMAL GRADIENT...HIGHEST MIXED LAYER CAPE) ARE ALL WELL
SOUTH OF INTERSTATE 94 AND ACTUALLY NEAR AND SOUTH OF INTERSTATE
80 AS THE UPPER WAVE MOVES THROUGH EARLY TONIGHT. WE SHOULD SEE
SOME CONVECTION OVER OUR SRN ONE OR TWO ROWS OF COUNTIES MID
EVENING AS THE WAVE MOVES IN. DEFORMATION ZONE RAIN WILL FOLLOW
DURING THE OVERNIGHT HOURS. THE HEAVIEST OF THAT WILL BE NEAR AND
SOUTH OF INTERSTATE 94.
THERE IS A CONVECTIVE COMPLEX OVER E CNTL MN AT 10 AM HEADING
EAST. THAT IS ON THE TAIL OF THE PV MAX ASSOCIATED WITH THE
CONVECTION THAT CROSSED MN AND WI EARLIER AND HAS SINCE DIED. THAT
PV MAX MOVES THROUGH OUR CNTL CWA THIS AFTERNOON. I BELIEVE THAT
WILL BE THE FOCUS FOR OUR AFTERNOON CONVECTION. THE INSTABILITY IS
MARGINAL (LOOKING AT RAP SOUNDING THIS AFTERNOON) FOR THIS
CONVECTION SO I DO NOT BELIEVE THIS WILL BE SEVERE... MOSTLY JUST
GENERIC THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
FORECAST CONCERNS DEAL WITH CONVECTIVE TRENDS THIS MORNING THROUGH
THIS EVENING.
LATEST REGIONAL RADAR SHOWS THAT STORMS HAVE FIRED AS EXPECTED IN
NORTHEAST NEBRASKA ON THE NOSE OF A STRONG LLJ. THESE STORMS HAVE
MOVED INTO NW IOWA. A BIT FARTHER NORTH OVER SOUTH DAKOTA ANOTHER
AREA OF STORMS IS MOVE EWD. THESE ARE ASSOCIATED WITH A SHORT WAVE
MOVING ACROSS THE NRN PLAINS. SHORT RANGE MODELS MOVE THIS SHORT
WAVE SEWD TOWARD CHICAGO BY THIS AFTERNOON AT THE SAME TIME THE SFC
LOW IN SRN NEBRASKA IS MOVING ENEWD. HRRR SHOWS BOTH CLUSTERS OF
STORMS WEAKENING AS THEY MOVE EAST WITH THE IOWA CONVECTION MOVING
TO THE WRN CWA BY NOON OR SO AS MOSTLY SHOWERS.
CONVECTION REDEVELOPS OVER NW IOWA BY EARLY AFTERNOON AS STRONG
DYNAMICS TAKE SHAPE. SBCAPE AROUND 3K J/KG COUPLED WITH STRONG
MOISTURE CONVERGENCE...60-70KTS BULK SHEAR AND LIFT FROM THE
APPROACHING SHORT WAVE SHOULD RESULT IN STRONG TO SEVERE STORMS
DEVELOPING OVER ILLINOIS AND MOVING ESE TOWARD THE SRN CWA. A 50KT
MID LEVEL JET WILL PUSH THE STORMS EWD...PERHAPS AS A DERECHO. CAN/T
ARGUE TOO MUCH WITH THE POSITION OF THE DAY ONE SLIGHT AND MODERATE
RISK AREAS. THIS ISN/T A SLAM DUNK BY ANY MEANS BUT THE HIGHEST
THREAT FOR STRONG/SVR STORMS WILL BE SOUTH OF A MUSKEGON TO LANSING
LINE. LATEST NAM ALSO PUSHES THE WARM FRONT INTO THE SRN CWA THIS
AFTERNOON. SO...WITH THE WARM FRONT IN PLACE WE CAN/T RULE OUT A
TORNADO EITHER.
THE SVR THREAT WILL END THIS EVENING AS THE LOW MOVES BY TO THE
SOUTH AND QUIETER WEATHER WILL RETURN THURSDAY AND FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
UPPER RIDGING WILL EXTEND FROM THE GULF COAST NORTH INTO THE UPPER
MID WEST FRIDAY NIGHT. THE RIDGING WILL BE FLATTENED THROUGH THE
LONG TERM AS A SERIES OF SHORTWAVE/S CREST THE RIDGE AND MOVE
THROUGH THE GREAT LAKES REGION. THE FIRST OF WHICH MOVES INTO THE
AREA ON SATURDAY. THE SECOND AND MORE SUBSTANTIAL WAVE DIGS INTO THE
GREAT LAKES REGION SUNDAY INTO MONDAY.
AT THE SURFACE RIDGING WILL BE IN PLACE FRIDAY NIGHT AND BRING DRY
WEATHER. THE HIGH SLIPS EAST QUICKLY ON SATURDAY WHICH SHOULD ALLOW
CHANCES FOR SHOWERS AND STORMS DURING THE AFTERNOON AHEAD OF THE
UPPER SHORTWAVE. THE CHANCES WILL CONTINUE INTO SATURDAY NIGHT AS A
WAVE OF LOW PRESSURE SLIDES THROUGH THE AREA AT THE SURFACE.
SUNDAY INTO MONDAY CHANCES FOR SHOWERS AND STORMS WILL CONTINUE AS
THE SECOND MORE POTENT UPPER TROUGH DIGS INTO THE GREAT LAKES.
SURFACE FEATURES ARE BIT MORE HARD TO DISCERN IN THIS TIME FRAME AS
THE GFS IS FURTHER NORTH AND DEEPER WITH THE SURFACE WAVE. FOLLOWED
THE GFS CLOSER HERE AS IT MAKES MORE SENSE TO HAVE A DEEPER FARTHER
NORTH WAVE GIVEN THE UPPER PATTERN. WE LOOK TO DRY OUT MONDAY NIGHT
INTO TUESDAY AS HIGH PRESSURE BUILDS IN.
TEMPERATURES THROUGH THE PERIOD SHOULD BE SEASONABLE DESPITE THE
RIDGING DAMPENING OUT. HEIGHTS ARE STILL FAIRLY HIGH AND 850MB TEMPS
ARE FORECAST TO BE IN THE TEENS C. HIGHS SHOULD BE IN THE UPPER 70S
TO AROUND 80 EACH DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 747 AM EDT WED JUN 12 2013
MAIN CONCERN TODAY WILL BE THUNDERSTORM EVOLUTION...COVERAGE AND
SEVERITY. VFR CEILINGS ARE IN PLACE AT DAYBREAK...WITH SOME MVFR
VSBY/S IN FOG. THE EXPECTATION IS THE FOG WILL LIFT THIS
MORNING...GIVING WAY TO VFR CONDITIONS BY LATE MORNING. SOME
SCATTERED SHOWERS ARE EXPECTED THROUGH THE MORNING...BUT MOST WILL
BE LIGHT AND NOT IMPACT CONDITIONS MUCH.
THE FOCUS THIS AFTERNOON AND EVENING IS ON THUNDERSTORMS. A COUPLE
SCENARIOS ARE IN PLAY WITH STORMS SWEEPING IN OFF OF LAKE MICHIGAN
AS EARLY AS NOON TO 100PM. THEY WOULD MOVE THROUGH THE TAF SITES
THIS AFTERNOON WITH THE POTENTIAL FOR SIGNIFICANT WIND
GUSTS...OVER 50 KNOTS. A SECOND SCENARIO WOULD HAVE THE STORMS SWEEP
IN LATER THIS EVENING WITH A MAINLY DRY AFTERNOON. BOTH SCENARIOS
WILL HAVE SIGNIFICANT WIND POTENTIAL AS WELL AS HAIL. ANY STORMS
THAT DEVELOP TODAY COULD BE SEVERE. NORTHERLY WINDS WILL DEVELOP
TONIGHT IN THE WAKE OF THE STORMS WITH MVFR CEILINGS AND POSSIBLY
VSBY/S (FOG) DEVELOPING.
USED VCTS IS THIS MORNING/S TAFS GIVEN THE UNCERTAINTY. LATER
UPDATES WILL PROVIDE GREATER DETAIL.
&&
.MARINE...
ISSUED AT 330 AM EDT WED JUN 12 2013
FAIRLY LIGHT WINDS WILL CONTINUE OVER THE LAKE RESULTING IN LOW WAVE
HEIGHTS. PATCHY DENSE FOG IS POSSIBLE DUE TO HIGH DEWPOINTS OVER THE
COLDER WATER SFC. NORTH WINDS WILL DEVELOP THURSDAY AND A SMALL
CRAFT ADVISORY MAY BE NEEDED.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT WED JUN 12 2013
THE MAIN PERIOD OF CONCERN IS THIS AFTERNOON AND EVENING. HEAVY
RAINFALL WILL BE POSSIBLE ACROSS THE SRN HALF OF THE CWA DURING THIS
TIME. AN INCH TO TWO INCHES SEEMS PLAUSIBLE ESPECIALLY SOUTH OF
I-94. THIS MAY LEAD TO LOCALIZED FLOODING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1044 AM EDT WED JUN 12 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 330 AM EDT WED JUN 12 2013
AS LOW PRESSURE MOVES EAST FROM THE PLAINS TOWARD NORTHERN INDIANA
TODAY SHOWERS AND THUNDERSTORMS WILL DEVELOP. SOME OF THE STORMS
COULD BE STRONG TO SEVERE ESPECIALLY SOUTH OF I-94 WITH HIGH WINDS
THE MAIN THREAT. HEAVY RAIN WILL BE POSSIBLE THIS AFTERNOON AND
EVENING TOO SOUTH OF I-96. QUIETER WEATHER WILL RETURN THURSDAY
THROUGH SATURDAY AS THE LOW MOVES EAST AND NORTH WINDS ADVECT DRIER
AIR INTO LOWER MICHIGAN.
&&
.UPDATE...
ISSUED AT 1043 AM EDT WED JUN 12 2013
MY CURRENT THINKING IS THE BEST THREAT FOR SEVERE STORMS WILL BE
THIS EVENING INTO EARLY TONIGHT. THE DENSE MID AND HIGH CLOUD
COVER OVER MN/WI/LWR MI WILL CAUSE THE BEST DESTABILIZATION TO BE
WELL SOUTH OF OUR AREA THIS AFTERNOON. SO... THE STRONGEST
THUNDERSTORMS WILL BE ASSOCIATED WITH THE MAIN UPPER LEVEL WAVE
MOVING THROUGH THIS EVENING. THIS IDEA IS SUPPORTED BY THE LATEST
12Z NAM...12Z HRRR...00Z SPC WRF...12 RAP MODELS.
THE BEST FORCING (MOISTURE TRANSPORT VECTORS 1000/850...LOW LEVEL
JET AND THERMAL GRADIENT...HIGHEST MIXED LAYER CAPE) ARE ALL WELL
SOUTH OF INTERSTATE 94 AND ACTUALLY NEAR AND SOUTH OF INTERSTATE
80 AS THE UPPER WAVE MOVES THROUGH EARLY TONIGHT. WE SHOULD SEE
SOME CONVECTION OVER OUR SRN ONE OR TWO ROWS OF COUNTIES MID
EVENING AS THE WAVE MOVES IN. DEFORMATION ZONE RAIN WILL FOLLOW
DURING THE OVERNIGHT HOURS. THE HEAVIEST OF THAT WILL BE NEAR AND
SOUTH OF INTERSTATE 94.
THERE IS A CONVECTIVE COMPLEX OVER E CNTL MN AT 10 AM HEADING
EAST. THAT IS ON THE TAIL OF THE PV MAX ASSOCIATED WITH THE
CONVECTION THAT CROSSED MN AND WI EARLIER AND HAS SINCE DIED. THAT
PV MAX MOVES THROUGH OUR CNTL CWA THIS AFTERNOON. I BELIEVE THAT
WILL BE THE FOCUS FOR OUR AFTERNOON CONVECTION. THE INSTABILITY IS
MARGINAL (LOOKING AT RAP SOUNDING THIS AFTERNOON) FOR THIS
CONVECTION SO I DO NOT BELIEVE THIS WILL BE SEVERE... MOSTLY JUST
GENERIC THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
FORECAST CONCERNS DEAL WITH CONVECTIVE TRENDS THIS MORNING THROUGH
THIS EVENING.
LATEST REGIONAL RADAR SHOWS THAT STORMS HAVE FIRED AS EXPECTED IN
NORTHEAST NEBRASKA ON THE NOSE OF A STRONG LLJ. THESE STORMS HAVE
MOVED INTO NW IOWA. A BIT FARTHER NORTH OVER SOUTH DAKOTA ANOTHER
AREA OF STORMS IS MOVE EWD. THESE ARE ASSOCIATED WITH A SHORT WAVE
MOVING ACROSS THE NRN PLAINS. SHORT RANGE MODELS MOVE THIS SHORT
WAVE SEWD TOWARD CHICAGO BY THIS AFTERNOON AT THE SAME TIME THE SFC
LOW IN SRN NEBRASKA IS MOVING ENEWD. HRRR SHOWS BOTH CLUSTERS OF
STORMS WEAKENING AS THEY MOVE EAST WITH THE IOWA CONVECTION MOVING
TO THE WRN CWA BY NOON OR SO AS MOSTLY SHOWERS.
CONVECTION REDEVELOPS OVER NW IOWA BY EARLY AFTERNOON AS STRONG
DYNAMICS TAKE SHAPE. SBCAPE AROUND 3K J/KG COUPLED WITH STRONG
MOISTURE CONVERGENCE...60-70KTS BULK SHEAR AND LIFT FROM THE
APPROACHING SHORT WAVE SHOULD RESULT IN STRONG TO SEVERE STORMS
DEVELOPING OVER ILLINOIS AND MOVING ESE TOWARD THE SRN CWA. A 50KT
MID LEVEL JET WILL PUSH THE STORMS EWD...PERHAPS AS A DERECHO. CAN/T
ARGUE TOO MUCH WITH THE POSITION OF THE DAY ONE SLIGHT AND MODERATE
RISK AREAS. THIS ISN/T A SLAM DUNK BY ANY MEANS BUT THE HIGHEST
THREAT FOR STRONG/SVR STORMS WILL BE SOUTH OF A MUSKEGON TO LANSING
LINE. LATEST NAM ALSO PUSHES THE WARM FRONT INTO THE SRN CWA THIS
AFTERNOON. SO...WITH THE WARM FRONT IN PLACE WE CAN/T RULE OUT A
TORNADO EITHER.
THE SVR THREAT WILL END THIS EVENING AS THE LOW MOVES BY TO THE
SOUTH AND QUIETER WEATHER WILL RETURN THURSDAY AND FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
UPPER RIDGING WILL EXTEND FROM THE GULF COAST NORTH INTO THE UPPER
MID WEST FRIDAY NIGHT. THE RIDGING WILL BE FLATTENED THROUGH THE
LONG TERM AS A SERIES OF SHORTWAVE/S CREST THE RIDGE AND MOVE
THROUGH THE GREAT LAKES REGION. THE FIRST OF WHICH MOVES INTO THE
AREA ON SATURDAY. THE SECOND AND MORE SUBSTANTIAL WAVE DIGS INTO THE
GREAT LAKES REGION SUNDAY INTO MONDAY.
AT THE SURFACE RIDGING WILL BE IN PLACE FRIDAY NIGHT AND BRING DRY
WEATHER. THE HIGH SLIPS EAST QUICKLY ON SATURDAY WHICH SHOULD ALLOW
CHANCES FOR SHOWERS AND STORMS DURING THE AFTERNOON AHEAD OF THE
UPPER SHORTWAVE. THE CHANCES WILL CONTINUE INTO SATURDAY NIGHT AS A
WAVE OF LOW PRESSURE SLIDES THROUGH THE AREA AT THE SURFACE.
SUNDAY INTO MONDAY CHANCES FOR SHOWERS AND STORMS WILL CONTINUE AS
THE SECOND MORE POTENT UPPER TROUGH DIGS INTO THE GREAT LAKES.
SURFACE FEATURES ARE BIT MORE HARD TO DISCERN IN THIS TIME FRAME AS
THE GFS IS FURTHER NORTH AND DEEPER WITH THE SURFACE WAVE. FOLLOWED
THE GFS CLOSER HERE AS IT MAKES MORE SENSE TO HAVE A DEEPER FARTHER
NORTH WAVE GIVEN THE UPPER PATTERN. WE LOOK TO DRY OUT MONDAY NIGHT
INTO TUESDAY AS HIGH PRESSURE BUILDS IN.
TEMPERATURES THROUGH THE PERIOD SHOULD BE SEASONABLE DESPITE THE
RIDGING DAMPENING OUT. HEIGHTS ARE STILL FAIRLY HIGH AND 850MB TEMPS
ARE FORECAST TO BE IN THE TEENS C. HIGHS SHOULD BE IN THE UPPER 70S
TO AROUND 80 EACH DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 747 AM EDT WED JUN 12 2013
MAIN CONCERN TODAY WILL BE THUNDERSTORM EVOLUTION...COVERAGE AND
SEVERITY. VFR CEILINGS ARE IN PLACE AT DAYBREAK...WITH SOME MVFR
VSBY/S IN FOG. THE EXPECTATION IS THE FOG WILL LIFT THIS
MORNING...GIVING WAY TO VFR CONDITIONS BY LATE MORNING. SOME
SCATTERED SHOWERS ARE EXPECTED THROUGH THE MORNING...BUT MOST WILL
BE LIGHT AND NOT IMPACT CONDITIONS MUCH.
THE FOCUS THIS AFTERNOON AND EVENING IS ON THUNDERSTORMS. A COUPLE
SCENARIOS ARE IN PLAY WITH STORMS SWEEPING IN OFF OF LAKE MICHIGAN
AS EARLY AS NOON TO 100PM. THEY WOULD MOVE THROUGH THE TAF SITES
THIS AFTERNOON WITH THE POTENTIAL FOR SIGNIFICANT WIND
GUSTS...OVER 50 KNOTS. A SECOND SCENARIO WOULD HAVE THE STORMS SWEEP
IN LATER THIS EVENING WITH A MAINLY DRY AFTERNOON. BOTH SCENARIOS
WILL HAVE SIGNIFICANT WIND POTENTIAL AS WELL AS HAIL. ANY STORMS
THAT DEVELOP TODAY COULD BE SEVERE. NORTHERLY WINDS WILL DEVELOP
TONIGHT IN THE WAKE OF THE STORMS WITH MVFR CEILINGS AND POSSIBLY
VSBY/S (FOG) DEVELOPING.
USED VCTS IS THIS MORNING/S TAFS GIVEN THE UNCERTAINTY. LATER
UPDATES WILL PROVIDE GREATER DETAIL.
&&
.MARINE...
ISSUED AT 330 AM EDT WED JUN 12 2013
FAIRLY LIGHT WINDS WILL CONTINUE OVER THE LAKE RESULTING IN LOW WAVE
HEIGHTS. PATCHY DENSE FOG IS POSSIBLE DUE TO HIGH DEWPOINTS OVER THE
COLDER WATER SFC. NORTH WINDS WILL DEVELOP THURSDAY AND A SMALL
CRAFT ADVISORY MAY BE NEEDED.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT WED JUN 12 2013
THE MAIN PERIOD OF CONCERN IS THIS AFTERNOON AND EVENING. HEAVY
RAINFALL WILL BE POSSIBLE ACROSS THE SRN HALF OF THE CWA DURING THIS
TIME. AN INCH TO TWO INCHES SEEMS PLAUSIBLE ESPECIALLY SOUTH OF
I-94. THIS MAY LEAD TO LOCALIZED FLOODING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
747 AM EDT WED JUN 12 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 330 AM EDT WED JUN 12 2013
AS LOW PRESSURE MOVES EAST FROM THE PLAINS TOWARD NORTHERN INDIANA
TODAY SHOWERS AND THUNDERSTORMS WILL DEVELOP. SOME OF THE STORMS
COULD BE STRONG TO SEVERE ESPECIALLY SOUTH OF I-94 WITH HIGH WINDS
THE MAIN THREAT. HEAVY RAIN WILL BE POSSIBLE THIS AFTERNOON AND
EVENING TOO SOUTH OF I-96. QUIETER WEATHER WILL RETURN THURSDAY
THROUGH SATURDAY AS THE LOW MOVES EAST AND NORTH WINDS ADVECT DRIER
AIR INTO LOWER MICHIGAN.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
FORECAST CONCERNS DEAL WITH CONVECTIVE TRENDS THIS MORNING THROUGH
THIS EVENING.
LATEST REGIONAL RADAR SHOWS THAT STORMS HAVE FIRED AS EXPECTED IN
NORTHEAST NEBRASKA ON THE NOSE OF A STRONG LLJ. THESE STORMS HAVE
MOVED INTO NW IOWA. A BIT FARTHER NORTH OVER SOUTH DAKOTA ANOTHER
AREA OF STORMS IS MOVE EWD. THESE ARE ASSOCIATED WITH A SHORT WAVE
MOVING ACROSS THE NRN PLAINS. SHORT RANGE MODELS MOVE THIS SHORT
WAVE SEWD TOWARD CHICAGO BY THIS AFTERNOON AT THE SAME TIME THE SFC
LOW IN SRN NEBRASKA IS MOVING ENEWD. HRRR SHOWS BOTH CLUSTERS OF
STORMS WEAKENING AS THEY MOVE EAST WITH THE IOWA CONVECTION MOVING
TO THE WRN CWA BY NOON OR SO AS MOSTLY SHOWERS.
CONVECTION REDEVELOPS OVER NW IOWA BY EARLY AFTERNOON AS STRONG
DYNAMICS TAKE SHAPE. SBCAPE AROUND 3K J/KG COUPLED WITH STRONG
MOISTURE CONVERGENCE...60-70KTS BULK SHEAR AND LIFT FROM THE
APPROACHING SHORT WAVE SHOULD RESULT IN STRONG TO SEVERE STORMS
DEVELOPING OVER ILLINOIS AND MOVING ESE TOWARD THE SRN CWA. A 50KT
MID LEVEL JET WILL PUSH THE STORMS EWD...PERHAPS AS A DERECHO. CAN/T
ARGUE TOO MUCH WITH THE POSITION OF THE DAY ONE SLIGHT AND MODERATE
RISK AREAS. THIS ISN/T A SLAM DUNK BY ANY MEANS BUT THE HIGHEST
THREAT FOR STRONG/SVR STORMS WILL BE SOUTH OF A MUSKEGON TO LANSING
LINE. LATEST NAM ALSO PUSHES THE WARM FRONT INTO THE SRN CWA THIS
AFTERNOON. SO...WITH THE WARM FRONT IN PLACE WE CAN/T RULE OUT A
TORNADO EITHER.
THE SVR THREAT WILL END THIS EVENING AS THE LOW MOVES BY TO THE
SOUTH AND QUIETER WEATHER WILL RETURN THURSDAY AND FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
UPPER RIDGING WILL EXTEND FROM THE GULF COAST NORTH INTO THE UPPER
MID WEST FRIDAY NIGHT. THE RIDGING WILL BE FLATTENED THROUGH THE
LONG TERM AS A SERIES OF SHORTWAVE/S CREST THE RIDGE AND MOVE
THROUGH THE GREAT LAKES REGION. THE FIRST OF WHICH MOVES INTO THE
AREA ON SATURDAY. THE SECOND AND MORE SUBSTANTIAL WAVE DIGS INTO THE
GREAT LAKES REGION SUNDAY INTO MONDAY.
AT THE SURFACE RIDGING WILL BE IN PLACE FRIDAY NIGHT AND BRING DRY
WEATHER. THE HIGH SLIPS EAST QUICKLY ON SATURDAY WHICH SHOULD ALLOW
CHANCES FOR SHOWERS AND STORMS DURING THE AFTERNOON AHEAD OF THE
UPPER SHORTWAVE. THE CHANCES WILL CONTINUE INTO SATURDAY NIGHT AS A
WAVE OF LOW PRESSURE SLIDES THROUGH THE AREA AT THE SURFACE.
SUNDAY INTO MONDAY CHANCES FOR SHOWERS AND STORMS WILL CONTINUE AS
THE SECOND MORE POTENT UPPER TROUGH DIGS INTO THE GREAT LAKES.
SURFACE FEATURES ARE BIT MORE HARD TO DISCERN IN THIS TIME FRAME AS
THE GFS IS FURTHER NORTH AND DEEPER WITH THE SURFACE WAVE. FOLLOWED
THE GFS CLOSER HERE AS IT MAKES MORE SENSE TO HAVE A DEEPER FARTHER
NORTH WAVE GIVEN THE UPPER PATTERN. WE LOOK TO DRY OUT MONDAY NIGHT
INTO TUESDAY AS HIGH PRESSURE BUILDS IN.
TEMPERATURES THROUGH THE PERIOD SHOULD BE SEASONABLE DESPITE THE
RIDGING DAMPENING OUT. HEIGHTS ARE STILL FAIRLY HIGH AND 850MB TEMPS
ARE FORECAST TO BE IN THE TEENS C. HIGHS SHOULD BE IN THE UPPER 70S
TO AROUND 80 EACH DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 747 AM EDT WED JUN 12 2013
MAIN CONCERN TODAY WILL BE THUNDERSTORM EVOLUTION...COVERAGE AND
SEVERITY. VFR CEILINGS ARE IN PLACE AT DAYBREAK...WITH SOME MVFR
VSBY/S IN FOG. THE EXPECTATION IS THE FOG WILL LIFT THIS
MORNING...GIVING WAY TO VFR CONDITIONS BY LATE MORNING. SOME
SCATTERED SHOWERS ARE EXPECTED THROUGH THE MORNING...BUT MOST WILL
BE LIGHT AND NOT IMPACT CONDITIONS MUCH.
THE FOCUS THIS AFTERNOON AND EVENING IS ON THUNDERSTORMS. A COUPLE
SCENARIOS ARE IN PLAY WITH STORMS SWEEPING IN OFF OF LAKE MICHIGAN
AS EARLY AS NOON TO 100PM. THEY WOULD MOVE THROUGH THE TAF SITES
THIS AFTERNOON WITH THE POTENTIAL FOR SIGNIFICANT WIND
GUSTS...OVER 50 KNOTS. A SECOND SCENARIO WOULD HAVE THE STORMS SWEEP
IN LATER THIS EVENING WITH A MAINLY DRY AFTERNOON. BOTH SCENARIOS
WILL HAVE SIGNIFICANT WIND POTENTIAL AS WELL AS HAIL. ANY STORMS
THAT DEVELOP TODAY COULD BE SEVERE. NORTHERLY WINDS WILL DEVELOP
TONIGHT IN THE WAKE OF THE STORMS WITH MVFR CEILINGS AND POSSIBLY
VSBY/S (FOG) DEVELOPING.
USED VCTS IS THIS MORNING/S TAFS GIVEN THE UNCERTAINTY. LATER
UPDATES WILL PROVIDE GREATER DETAIL.
&&
.MARINE...
ISSUED AT 330 AM EDT WED JUN 12 2013
FAIRLY LIGHT WINDS WILL CONTINUE OVER THE LAKE RESULTING IN LOW WAVE
HEIGHTS. PATCHY DENSE FOG IS POSSIBLE DUE TO HIGH DEWPOINTS OVER THE
COLDER WATER SFC. NORTH WINDS WILL DEVELOP THURSDAY AND A SMALL
CRAFT ADVISORY MAY BE NEEDED.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT WED JUN 12 2013
THE MAIN PERIOD OF CONCERN IS THIS AFTERNOON AND EVENING. HEAVY
RAINFALL WILL BE POSSIBLE ACROSS THE SRN HALF OF THE CWA DURING THIS
TIME. AN INCH TO TWO INCHES SEEMS PLAUSIBLE ESPECIALLY SOUTH OF
I-94. THIS MAY LEAD TO LOCALIZED FLOODING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
330 AM EDT WED JUN 12 2013
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 330 AM EDT WED JUN 12 2013
AS LOW PRESSURE MOVES EAST FROM THE PLAINS TOWARD NORTHERN INDIANA
TODAY SHOWERS AND THUNDERSTORMS WILL DEVELOP. SOME OF THE STORMS
COULD BE STRONG TO SEVERE ESPECIALLY SOUTH OF I-94 WITH HIGH WINDS
THE MAIN THREAT. HEAVY RAIN WILL BE POSSIBLE THIS AFTERNOON AND
EVENING TOO SOUTH OF I-96. QUIETER WEATHER WILL RETURN THURSDAY
THROUGH SATURDAY AS THE LOW MOVES EAST AND NORTH WINDS ADVECT DRIER
AIR INTO LOWER MICHIGAN.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
FORECAST CONCERNS DEAL WITH CONVECTIVE TRENDS THIS MORNING THROUGH
THIS EVENING.
LATEST REGIONAL RADAR SHOWS THAT STORMS HAVE FIRED AS EXPECTED IN
NORTHEAST NEBRASKA ON THE NOSE OF A STRONG LLJ. THESE STORMS HAVE
MOVED INTO NW IOWA. A BIT FARTHER NORTH OVER SOUTH DAKOTA ANOTHER
AREA OF STORMS IS MOVE EWD. THESE ARE ASSOCIATED WITH A SHORT WAVE
MOVING ACROSS THE NRN PLAINS. SHORT RANGE MODELS MOVE THIS SHORT
WAVE SEWD TOWARD CHICAGO BY THIS AFTERNOON AT THE SAME TIME THE SFC
LOW IN SRN NEBRASKA IS MOVING ENEWD. HRRR SHOWS BOTH CLUSTERS OF
STORMS WEAKENING AS THEY MOVE EAST WITH THE IOWA CONVECTION MOVING
TO THE WRN CWA BY NOON OR SO AS MOSTLY SHOWERS.
CONVECTION REDEVELOPS OVER NW IOWA BY EARLY AFTERNOON AS STRONG
DYNAMICS TAKE SHAPE. SBCAPE AROUND 3K J/KG COUPLED WITH STRONG
MOISTURE CONVERGENCE...60-70KTS BULK SHEAR AND LIFT FROM THE
APPROACHING SHORT WAVE SHOULD RESULT IN STRONG TO SEVERE STORMS
DEVELOPING OVER ILLINOIS AND MOVING ESE TOWARD THE SRN CWA. A 50KT
MID LEVEL JET WILL PUSH THE STORMS EWD...PERHAPS AS A DERECHO. CAN/T
ARGUE TOO MUCH WITH THE POSITION OF THE DAY ONE SLIGHT AND MODERATE
RISK AREAS. THIS ISN/T A SLAM DUNK BY ANY MEANS BUT THE HIGHEST
THREAT FOR STRONG/SVR STORMS WILL BE SOUTH OF A MUSKEGON TO LANSING
LINE. LATEST NAM ALSO PUSHES THE WARM FRONT INTO THE SRN CWA THIS
AFTERNOON. SO...WITH THE WARM FRONT IN PLACE WE CAN/T RULE OUT A
TORNADO EITHER.
THE SVR THREAT WILL END THIS EVENING AS THE LOW MOVES BY TO THE
SOUTH AND QUIETER WEATHER WILL RETURN THURSDAY AND FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EDT WED JUN 12 2013
UPPER RIDGING WILL EXTEND FROM THE GULF COAST NORTH INTO THE UPPER
MID WEST FRIDAY NIGHT. THE RIDGING WILL BE FLATTENED THROUGH THE
LONG TERM AS A SERIES OF SHORTWAVE/S CREST THE RIDGE AND MOVE
THROUGH THE GREAT LAKES REGION. THE FIRST OF WHICH MOVES INTO THE
AREA ON SATURDAY. THE SECOND AND MORE SUBSTANTIAL WAVE DIGS INTO THE
GREAT LAKES REGION SUNDAY INTO MONDAY.
AT THE SURFACE RIDGING WILL BE IN PLACE FRIDAY NIGHT AND BRING DRY
WEATHER. THE HIGH SLIPS EAST QUICKLY ON SATURDAY WHICH SHOULD ALLOW
CHANCES FOR SHOWERS AND STORMS DURING THE AFTERNOON AHEAD OF THE
UPPER SHORTWAVE. THE CHANCES WILL CONTINUE INTO SATURDAY NIGHT AS A
WAVE OF LOW PRESSURE SLIDES THROUGH THE AREA AT THE SURFACE.
SUNDAY INTO MONDAY CHANCES FOR SHOWERS AND STORMS WILL CONTINUE AS
THE SECOND MORE POTENT UPPER TROUGH DIGS INTO THE GREAT LAKES.
SURFACE FEATURES ARE BIT MORE HARD TO DISCERN IN THIS TIME FRAME AS
THE GFS IS FURTHER NORTH AND DEEPER WITH THE SURFACE WAVE. FOLLOWED
THE GFS CLOSER HERE AS IT MAKES MORE SENSE TO HAVE A DEEPER FARTHER
NORTH WAVE GIVEN THE UPPER PATTERN. WE LOOK TO DRY OUT MONDAY NIGHT
INTO TUESDAY AS HIGH PRESSURE BUILDS IN.
TEMPERATURES THROUGH THE PERIOD SHOULD BE SEASONABLE DESPITE THE
RIDGING DAMPENING OUT. HEIGHTS ARE STILL FAIRLY HIGH AND 850MB TEMPS
ARE FORECAST TO BE IN THE TEENS C. HIGHS SHOULD BE IN THE UPPER 70S
TO AROUND 80 EACH DAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1145 PM EDT TUE JUN 11 2013
EXPECT FOG AND LOW CLOUDS TO FORM BY 10Z WITH SOME IFR AND EVEN
LIFR UNTIL AROUND 14Z. THEN MVFR OR VFR MOST OF THE DAY WITH
SHOWERS AND THUNDERSTORMS EXPECTED IN THE AFTERNOON AND EVENING.
SQUALL LINE SHOULD REMAIN SOUTH OF LOWER MICHIGAN WITH WINDS
REMAINING AOB 10 KNOTS FROM THE SOUTHEAST.
&&
.MARINE...
ISSUED AT 330 AM EDT WED JUN 12 2013
FAIRLY LIGHT WINDS WILL CONTINUE OVER THE LAKE RESULTING IN LOW WAVE
HEIGHTS. PATCHY DENSE FOG IS POSSIBLE DUE TO HIGH DEWPOINTS OVER THE
COLDER WATER SFC. NORTH WINDS WILL DEVELOP THURSDAY AND A SMALL
CRAFT ADVISORY MAY BE NEEDED.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT WED JUN 12 2013
THE MAIN PERIOD OF CONCERN IS THIS AFTERNOON AND EVENING. HEAVY
RAINFALL WILL BE POSSIBLE ACROSS THE SRN HALF OF THE CWA DURING THIS
TIME. AN INCH TO TWO INCHES SEEMS PLAUSIBLE ESPECIALLY SOUTH OF
I-94. THIS MAY LEAD TO LOCALIZED FLOODING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...OSTUNO
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
300 PM CDT WED JUN 12 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 259 PM CDT WED JUN 12 2013
AFTER TSTMS EXIT THE AREA THIS EVENING...WEATHER WILL BE MUCH
QUIETER...AND DRIER ON THU. AN UPPER LEVEL FEATURE SPINNING IN NE
SD IS RESPONSIBLE FOR TSTMS ACROSS S MN. CLUSTERS OF STORMS
CONTINUE TO DEVELOP JUST AHEAD OF THE UPPER FEATURE IN SW/SC
MN...WITH INDIVIDUAL CELLS MOVING NE WHILE THE SYSTEM AS A WHOLE
SHIFTS SE. SO FAR TODAY...THE BIGGEST THREAT IN OUR AREA HAS BEEN
HEAVY RAIN AND LOCALIZED FLOODING AS SEVERAL LOCATIONS HAVE
RECEIVED 3+ INCHES OF RAIN. THE PROSPECTS OF ADDITIONAL SEVERE WX
ACROSS S MN/W WI IS LOW DUE TO THE BULK OF THE DYNAMICS/
INSTABILITY FOCUSED ALONG THE FRONT TO OUR S AND E...BUT ANY
ISOLATED SEVERE WX WE DO GET SHOULD BE OF THE WIND VARIETY. THE
LAST OF THE -SHRA/TS SHOULD EXIT MPX CWA BY 02Z...WITH CLEARING
RAPIDLY MOVING IN FROM N TO S. HIGH PRESSURE IN THE WESTERN
DAKOTAS WILL SHIFT INTO W MN LATE TONIGHT...BUT WITH A SLOWLY
MOVING LOW HEADING INTO THE GREAT LAKES...THERE SHOULD BE ENOUGH
OF A GRADIENT TO PRECLUDE WIDESPREAD FOG FORMATION. WITH THAT
BEING SAID...WE DID INCLUDED PATCHY FOG ALONG THE MN RIVER VALLEY
AND WHERE SOME OF THE HEAVIEST RAIN FELL EARLIER TODAY. THURSDAY
SHOULD FEATURE PLENTY OF SUNSHINE AND TEMPS VERY NEAR AVERAGE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 259 PM CDT WED JUN 12 2013
HIGH PRESSURE/DRY WEATHER ACROSS THE REGION THURSDAY NIGHT WILL
GIVE WAY TO INCREASING SE FLOW ON FRIDAY AS A COLD FRONT
APPROACHES FROM THE NORTHERN PLAINS. SHOWERS AND A FEW
THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS WESTERN MN FRIDAY
MORNING AND SPREAD INTO EASTERN MN AND WEST CENTRAL WI BY FRIDAY
EVENING. THERE IS GOOD CONSENSUS WITHIN THE VARIOUS MODEL SOLUTIONS
THAT AN AREA OF LOW PRESSURE... ON THE TAIL END OF THE FRONT... WILL
MOVE EITHER ACROSS SOUTHERN MN OR JUST TO THE SOUTH OF THE STATE FRIDAY
NIGHT. THIS WILL NOT ONLY BE THE FOCUS FOR SEVERE WEATHER BUT
PERHAPS ANOTHER HEAVY RAIN EVENT. THE LOW LEVEL MOISTURE TRANSPORT
IS AIMED AT FAR SOUTHERN MN LATE IN THE DAY ON FRIDAY AND INCREASES
DURING THE EVENING AS THE LOW LEVEL JET STRENGTHENS. FORECAST PW
VALUES ARE NOT QUITE AS HIGH AS THIS MORNING...BUT STILL NEARLY
1.75 INCHES... OR ABOUT 160 PERCENT OF NORMAL. THIS IS RIGHT AROUND 2
STANDARD DEVIATIONS ABOVE NORMAL. HENCE...HIGH POPS REMAIN IN PLAY
FOR FRIDAY NIGHT ACROSS THE FA.
THE NAM IS THE ONLY SOLUTION THAT DRIES THE CWA EARLY ON SATURDAY
AS IT PUSHES THE FRONT EAST AND SOUTH OF THE FA. THE GEM/GFS/ECMWF
KEEP THE BOUNDARY NEAR THE MN/WI BORDER ON SOUTHWEST WITH SOME
SHOWERS AND THUNDERSTORMS POSSIBLE. THE FORECAST REFLECTS THE
LATTER SOLUTIONS WITH SMALL POPS HELD ON TO FOR SATURDAY/SATURDAY
NIGHT. A SLIGHT CHANCE FOR SHOWERS CONTINUES ON SUNDAY AS A RATHER
STRONG SHORT WAVE BEGINS TO DROP IN FROM SOUTH CENTRAL CANADA. ITS
QUITE POSSIBLE MUCH OF THE DAY MAY BE DRY WITH SHOWERS/ISOLATED
THUNDERSTORMS HOLDING OFF UNTIL THE EVENING AND OVERNIGHT HOURS.
THIS FEATURE WILL MOVE ON MONDAY WITH THE SHOWERS DIMINISHING
FROM NW TO SE THROUGH THE DAY.
WE ARE STILL LOOKING AT THE POTENTIAL FOR UPPER LEVEL RIDGING TO
BUILD OVER THE NORTHERN PLAINS AND THE UPPER MISSISSIPPI VALLEY
REGION FOR TUESDAY AND WEDNESDAY WITH PERHAPS A FEW DAYS OF DRY
WEATHER BACK TO BACK. THE PATTERN DOES NOT HOLD LONG AS MORE UPPER
LEVEL TROUGHING IS INDICATED TO MOVE INTO THE FA FOR THE END OF
NEXT WEEK ALONG WITH MORE SHOWERS AND THUNDERSTORMS. AFTER A COOL
START WITH HIGHS/LOWS THURSDAY AND FRIDAY...READINGS FROM SATURDAY
THROUGH NEXT WEDNESDAY LOOK TO BE AT OR ABOVE SEASONAL LEVELS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1223 PM CDT WED JUN 12 2013
SCATTERED CONVECTION IS ONGOING ACROSS THE ENTIRE AREA
OUT AHEAD OF AN UPPER LOW CURRENTLY IN NE SD. AS THIS LOW MOVES
ACROSS SOUTH CENTRAL MN THIS EVENING...STORMS WILL SHIFT SE...WITH
ALL TAF SITES FREE OF PRECIP BY 02Z. THE HI-RES HRRR MODEL SEEMS TO
HAVE A PRETTY GOOD HANDLE ON THE CURRENT SITUATION AND RELIED PRETTY
HEAVILY ON ITS DEPICTION OF TSRA ACROSS THE TAF SITES. IF/WHEN A
TSTMS MOVES OVER A SITE...EXPECT THE VIS TO DIP TO 1-3SM WITH +RA AND
THE POSSIBILITY OF WIND GUSTS TO 40KTS (DIRECTION BEING FAIRLY
VARIABLE WITH AN EMPHASIS ON N-E). AFTER CONVECTION MOVES OUT OF THE
AREA...WE SHOULD BE LEFT WITH A SMATTERING OF MID/HIGH CLOUDS FOR AT
LEAST THE FIRST HALF OF THE NIGHT ALONG WITH A NORTHERLY GRADIENT OF
5-10KTS. CLEARING SKIES LATER IN THE NIGHT AND A SLACKENING WIND IN
THE WEST AS HIGH PRESSURE SETTLES IN COULD LEAD TO FOG FORMATION
CONSIDERING ALL THE RAIN TODAY. WITH UNCERTAINTIES REGARDING EXTENT
OF HIGH CLOUDS AND WIND...HAVE ONLY INCLUDED FOG MENTION AT
KRWF...BUT THE POTENTIAL EXISTS FOR MOST SITES.
MSP...BAND OF STEADY -RA WILL BE NE OF THE AIRFIELD AT THE BEGINNING
OF THE PD...BUT SCT TSRA BACK TO THE SW WILL OCCASIONALLY IMPACT THE
AIRFIELD...MOST LIKELY BETWEEN 19-22Z. THE MAIN THREATS WILL BE
HEAVY RA AND POSSIBLY ERRATIC WIND GUSTS TO 35KTS. THE CONVECTIVE
THREAT SHOULD BE OVER BY 00Z WITH VFR PREVAILING. THERE IS A CHANCE
FOR A LITTLE FOG AROUND DAYBREAK THANKS TO THE SATURATED
GROUND...BUT THERE SHOULD BE ENOUGH OF A GRADIENT TO PRECLUDE ANY
LONG-LIVED VSBY RESTRICTIONS.
/OUTLOOK FOR KMSP/
THU NGT...VFR. E WIND 5 KTS.
FRI...VFR. SE WIND 10-20KTS.
FRI NGT...MVFR POSSIBLE. TSRA POSSIBLE. S BCMG W 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JCA
LONG TERM...RAH
AVIATION...JCA
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1225 PM CDT WED JUN 12 2013
UPDATED FOR AVIATION DISCUSSION BELOW
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CDT WED JUN 12 2013
ELEVATED CONVECTION SCATTERED ABOUT MUCH OF THE CWA THIS MORNING.
STEEP MID LEVEL LAPSE RATES AND AMPLE SHEAR FOR AT LEAST SOME
SMALL HAIL IN STRONGER STORMS. HIRES MODELS INDICATE SOME FORM OF
THUNDERSTORM COMPLEX WILL DEVELOP OVER FAR SOUTHERN MN EARLY THIS
MORNING....WITH PERHAPS REMNANTS OF THE CENTRAL DAKOTAS SYSTEM
MOVING INTO THE SOUTH LATER THIS MORNING AND EXITING TO THE
SOUTHEAST BY THIS EVENING. ATMOSPHERE REMAINS HIGHLY CAPPED OVER
THE FAR SOUTH...WITH HIGH CONVECTIVE INHIBITION NOTED. IF COMPLEX
DOES BECOME STRONG ENOUGH...COULD SEE SOME STRONG WINDS DEVELOP
WITH THE SYSTEM. DETERMINISTIC MODELS CONTINUE TO SHOW ACTIVITY
MOVING EAST SOUTHEAST AND OUT OF THE CWA BY 00Z THU. WILL CONTINUE
THIS TREND AS WELL...BEST INSTABILITY AND FORCING IS DRIVEN
SOUTHEAST OF THE AREA AT THAT TIME.
DRIER CONDITIONS WITH A CLEARING SKY EXPECTED FOR TONIGHT. GRADIENT
WINDS MAY BE STRONG ENOUGH TO PRECLUDE SIGNIFICANT FOG FORMATION
OVER THE WEST. THE SURFACE HIGH BUILDS INTO THAT REGION BY 12Z THU.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 333 AM CDT WED JUN 12 2013
THE EXTENDED RANGES OF THE FORECAST PERIOD WILL BE LITTERED WITH
OCCASIONAL SHOWER AND THUNDERSTORM CHANCES AS THE LARGE SCALE
PATTERN ALOFT REMAINS ACTIVE.
THURSDAY SHOULD BE DRY HOWEVER...AS MID LEVEL RIDGING PREVAILS
INTO THE UPPER MIDWEST. TEMPERATURES SHOULD BE NEAR SEASONAL
NORMALS...WITH HIGHS MOSTLY IN THE MID TO UPPER 70S.
THE DRY STINT WILL END ON FRIDAY...AS SOUTHERLY FLOW /MOISTURE
TRANSPORT/ ENSUES AHEAD OF AN APPROACHING NORTHERN ROCKIES UPPER
TROUGH. SHOULD SEE SHOWERS AND THUNDERSTORMS PUSHING FROM WEST TO
EAST ACROSS MN ON FRIDAY...WITH MORE WIDESPREAD ACTIVITY EXPECTED
ON FRIDAY NIGHT INTO SATURDAY AS DEPICTED BY PROGGED 305-310K
ISENTROPIC LIFT AND MOISTURE. WITH DECENT AGREEMENT AND CONSISTENCY
AMONGST THE GFS/ECMWF/NAM/ETC AND THEIR ILLUSTRATIONS OF THE
SURFACE TROUGH NOSING INTO SOUTHWEST MN ON FRIDAY NIGHT...LIKELY
POPS SEEM WARRANTED.
LESS CONFIDENT ON WIDESPREAD ACTIVITY ON SATURDAY...WITH THE UPPER
TROUGH EXPECTED TO HAVE LIFTED INTO SASKATCHEWAN...AND THE COLD
FRONT HAVING PASSED ACROSS AT LEAST A DECENT PORTION OF THE CWA.
THEREFORE...HAVE LIMITED CHANCE POPS TO THE SOUTHEASTERN PORTION
OF THE FORECAST AREA /SOUTH CENTRAL MN NORTHEAST ACROSS WEST
CENTRAL WI/. SATURDAY COULD END UP BEING A DRY DAY FOR A LARGE
PART OF THE AREA DEPENDING ON HOW QUICKLY THE FRONT PASSES.
THE AFOREMENTIONED UPPER LOW OPENS UP AND DROPS SOUTHEAST FROM
SASKATCHEWAN/MANITOBA ON SUNDAY INTO MONDAY. CONFIDENCE ON THE
STRENGTH/TIMING/MOISTURE IS LOW...SO POPS IN THE SUNDAY-MONDAY TIME FRAME
ARE IN THE 15-30 PERCENT RANGE.
AFTER THE WAVE DROPS ACROSS THE AREA...MID LEVEL RIDGING BUILDS
BACK INTO THE NORTH CENTRAL CONUS...WITH A DRYING AND WARMING TREND
EXPECTED INTO THE MIDDLE OF NEXT WEEK. HIGHS ATTENDANT WITH THE
ANTICIPATED PATTERN WOULD BE MORE SOLIDLY IN THE 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1223 PM CDT WED JUN 12 2013
SCATTERED CONVECTION IS ONGOING ACROSS THE ENTIRE AREA
OUT AHEAD OF AN UPPER LOW CURRENTLY IN NE SD. AS THIS LOW MOVES
ACROSS SOUTH CENTRAL MN THIS EVENING...STORMS WILL SHIFT SE...WITH
ALL TAF SITES FREE OF PRECIP BY 02Z. THE HI-RES HRRR MODEL SEEMS TO
HAVE A PRETTY GOOD HANDLE ON THE CURRENT SITUATION AND RELIED PRETTY
HEAVILY ON ITS DEPICTION OF TSRA ACROSS THE TAF SITES. IF/WHEN A
TSTMS MOVES OVER A SITE...EXPECT THE VIS TO DIP TO 1-3SM WITH +RA AND
THE POSSIBILITY OF WIND GUSTS TO 40KTS (DIRECTION BEING FAIRLY
VARIABLE WITH AN EMPHASIS ON N-E). AFTER CONVECTION MOVES OUT OF THE
AREA...WE SHOULD BE LEFT WITH A SMATTERING OF MID/HIGH CLOUDS FOR AT
LEAST THE FIRST HALF OF THE NIGHT ALONG WITH A NORTHERLY GRADIENT OF
5-10KTS. CLEARING SKIES LATER IN THE NIGHT AND A SLACKENING WIND IN
THE WEST AS HIGH PRESSURE SETTLES IN COULD LEAD TO FOG FORMATION
CONSIDERING ALL THE RAIN TODAY. WITH UNCERTAINTIES REGARDING EXTENT
OF HIGH CLOUDS AND WIND...HAVE ONLY INCLUDED FOG MENTION AT
KRWF...BUT THE POTENTIAL EXISTS FOR MOST SITES.
MSP...BAND OF STEADY -RA WILL BE NE OF THE AIRFIELD AT THE BEGINNING
OF THE PD...BUT SCT TSRA BACK TO THE SW WILL OCCASIONALLY IMPACT THE
AIRFIELD...MOST LIKELY BETWEEN 19-22Z. THE MAIN THREATS WILL BE
HEAVY RA AND POSSIBLY ERRATIC WIND GUSTS TO 35KTS. THE CONVECTIVE
THREAT SHOULD BE OVER BY 00Z WITH VFR PREVAILING. THERE IS A CHANCE
FOR A LITTLE FOG AROUND DAYBREAK THANKS TO THE SATURATED
GROUND...BUT THERE SHOULD BE ENOUGH OF A GRADIENT TO PRECLUDE ANY
LONG-LIVED VSBY RESTRICTIONS.
/OUTLOOK FOR KMSP/
THU NGT...VFR. E WIND 5 KTS.
FRI...VFR. SE WIND 10-20KTS.
FRI NGT...MVFR POSSIBLE. TSRA POSSIBLE. S BCMG W 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...DWE
LONG TERM...LS
AVIATION...JCA
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1258 PM CDT WED JUN 12 2013
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 337 AM CDT WED JUN 12 2013
MAIN CONCERN DEALS WITH POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON
INTO THE EVENING HOURS OVER PARTS OF THE CWA IF THUNDERSTORMS ARE
ABLE TO DEVELOP. IF THUNDERSTORMS DO DEVELOP...THEN THEY WILL
LIKELY BE SEVERE...PARTICULARLY OVER NORTHEAST MISSOURI INTO CENTRAL
ILLINOIS WITH DAMAGING WIND GUSTS IN EXCESS OF 70 MPH...LARGE HAIL
AND ISOLATED TORNADOES.
EXPECT MAINLY DRY CONDITIONS THROUGH THE MORNING HOURS AS THE
THUNDERSTORM COMPLEX CURRENTLY OVER WESTERN IOWA STAYS NORTH OF THE
AREA PER THE RAP FORWARD PROPAGATION VECTORS. OBSERVED AND FORECAST
SOUNDINGS STILL SHOW A VERY PRONOUNCED WARM LAYER BETWEEN 900-650MB
THROUGH LATE AFTERNOON WHICH SHOULD LIMIT THUNDERSTORM DEVELOPMENT.
THEREAFTER...THE TAIL END OF THE TROUGH CURRENTLY OVER THE HIGH
PLAINS WILL REACH THE MISSISSIPPI RIVER WHICH WILL ACT TO WEAKEN
THIS WARM LAYER AS THE ATTENDANT COLD FRONT MOVES SOUTHEAST ACROSS
THE CWA. MOST MODEL SOUNDINGS STILL SHOW SOME CONVECTIVE INHIBITION
OR VERY NARROW POSITIVE CAPE UP TO 700MB WHICH MAY KEEP
THUNDERSTORMS NORTH AND EAST OF THE AREA. WITH THIS SAID...MID
LEVEL FORCING AND LOW LEVEL MOISTURE CONVERGENCE IS WORTH KEEPING
SCATTERED THUNDERSTORMS IN THE FORECAST LATE THIS AFTERNOON INTO THE
EVENING AS THE COLD FRONT MOVES ACROSS THE CWA. INSTABILITY AND
SHEAR PARAMETERS FAVOR SEVERE THUNDERSTORMS WITH LATE AFTERNOON
MLCAPES AROUND 3000 J/KG AND 0-6KM SHEAR OF 40-50KTS. RELATIVELY
DRY AIR BELOW 700MB FAVORS THE POTENTIAL FOR DAMAGING WINDS
GUSTS...AND THERE IS A LARGE AMOUNT OF CAPE BETWEEN -10 AND -30C
WHICH SUGGESTS THE POTENTIAL FOR LARGE HAIL. SHEAR IS LINEAR IN THE
LOWEST LEVELS...THOUGH 0-1KM SHEAR NEAR 25KTS SUGGESTS TORNADOES ARE
ALSO POSSIBLE.
DID NOT CHANGE FORECAST HIGHS TODAY AS CURRENT TEMPERATURES ARE IN
THE 70S AND THERE WILL BE DECENT MIXING UP TO 850MB TODAY WITH MORE
SUN THAN YESTERDAY.
BRITT
.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUN 12 2013
AFTERNOON/EVENING CONVECTION SHOULD BE EXITING THE AREA BY 06Z.
CANNOT RULE OUT A STRAY SHOWER OR STORM OUT AHEAD OF OR RIGHT ON THE
COLD FRONT AS IT PUSHES THROUGH EAST CENTRAL AND SOUTHEAST MISSOURI
AND SOUTHERN ILLINOIS. NORTHWEST FLOW WILL BRING COOLER AND DRIER
AIR WITH SURFACE DEWPOINTS DROPPING BACK INTO THE UPPER 50S AND
LOWER 60S. 850MB TEMPS ALSO DROP INTO THE LOW TO MID TEENS BEHIND
THE FRONT. MODELS HAVE BEEN CONSISTENTLY AMPLIFYING THE FLOW
THURSDAY INTO FRIDAY WITH A FULL LONGWAVE TROF OVER THE EAST COAST
AND THE UPPER LEVEL RIDGE BUILDING ACROSS THE GREAT PLAINS INTO THE
UPPER MIDWEST. THIS SHOULD KEEP THE LOW LEVEL RIDGE LOCKED IN
ACROSS THE MISSISSIPPI VALLEY AT LEAST THROUGH FRIDAY. SEASONABLY
COOL GUIDANCE TEMPS LOOK PRETTY REASONABLE WITH AFOREMENTIONED COOL
AND DRY RIDGE IN PLACE. THERE IS A SMALL CHANCE THAT INCREASING
WARM ADVECTION ON THE WESTERN PERIPHERY OF THE LOW LEVEL RIDGE MAY
PRODUCE ISOLATED SHOWERS OR STORMS FRIDAY OVER PARTS OF CENTRAL AND
NORTHEAST MISSOURI SO HAVE SOME SLIGHT CHANCE POPS IN THOSE AREAS.
THE WEEKEND IS LOOKING MORE AND MORE STORMY AS THE UPPER LEVEL RIDGE
BREAKS DOWN IN RESPONSE TO A SHORTWAVE WHICH IS PULLED NORTHEAST OUT
OF THE GULF OF MEXICO. THIS WAVE IS LIKELY TO HAVE QUITE A BIT OF
MOISTURE ASSOCIATED WITH IT. AM UNSURE WHAT THE POTENTIAL FOR
SEVERE WEATHER WILL BE AT THIS TIME...BUT IT DOES LOOK LIKE THERE
WILL BE THUNDERSTORMS ON AND OFF FROM SATURDAY AFTERNOON AT LEAST
THROUGH SUNDAY NIGHT OR MONDAY AND SOME LOCALLY HEAVY RAIN MAY BE
POSSIBLE. TUESDAY LOOKS DRIER AS THE WAVE MOVES EAST AND WEAK
RIDGING BUILDS BACK ACROSS THE MID MISSISSIPPI VALLEY. TEMPERATURES
THROUGH THE PERIOD LOOK TO BE NEAR NORMAL.
CARNEY
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1230 PM CDT WED JUN 12 2013
A COLD FRONT CURRENTLY EXTENDING FROM WESTERN IOWA SOUTHWESTWARD
THROUGH EAST CENTRAL KANSAS WILL MOVE THROUGH THE AREA THIS
FORECAST PERIOD. CURRENT THINKING IS THAT DRY VFR CONDITIONS WILL
PREVAIL AT AREA TAF SITES THROUGH THE PERIOD...WITH A POTENTIAL TO
DECREASE TO LOW-END MVFR DURING THE LATE OVERNIGHT AND EARLY
MORNING HOURS ON THURSDAY AFTER FROPA. THE MAIN UNCERTAINTY THIS
FORECAST PERIOD REVOLVES AROUND TSRA CHANCES...WITH KUIN
MAINTAINING HIGHEST PROBABILITY OF SEEING SHRA/TSRA DURING THE
LATE AFTERNOON AND EARLY EVENING. ANY STORMS THAT DEVELOP COULD
BECOME SEVERE...ACCOMPANIED BY DAMAGING WINDS AND LARGE HAIL.
HOWEVER...FEEL THAT MAIN FOCUS FOR STORMS REMAINS FURTHER NORTH
ACROSS IOWA...THUS HAVE MAINTAINED VCTS IN THE KUIN TAF GIVEN
UNCERTAINTIES DUE TO COVERAGE THAT FAR SOUTH. WHILE THERE IS A
CHANCE FOR SOME SHRA/TSRA ACTIVITY AHEAD OF THE FRONT...EXPECT
MAJORITY OF THE COVERAGE TO REMAIN NORTH AND EAST OF METRO AREA
TAF SITES AT THIS TIME. EXPECT FROPA TO OCCUR AROUND THE 06-07Z
TIME FRAME AT KCOU AND KUIN...AND 08-09Z FOR METRO TAF SITES.
OTHERWISE...GUSTY SOUTHWEST WINDS WILL CONTINUE THROUGH THE
REMAINDER OF THE AFTERNOON BEFORE THE GUSTS DIMINISH AFTER SUNSET.
WINDS WILL GRADUALLY VEER TO THE NORTHWEST BEHIND THE
FRONT...AND DESPITE THE WINDS REMAINING BETWEEN 10-12KT...DO NOT
EXPECT IT TO BE AS GUSTY ON THURSDAY.
SPECIFICS FOR KSTL...
DRY AND VFR CONDITIONS SHOULD PREVAIL FOR A MAJORITY OF THIS
FORECAST PERIOD. THERE EXISTS THE POTENTIAL FOR SOME SHRA/TSRA
ACTIVITY AHEAD OF AN ADVANCING COLD FRONT...THOUGH CONFIDENCE
REMAINS TOO LOW TO INCLUDE MENTION IN THE TAF. LOW-END MVFR
CONDITIONS ARE POSSIBLE IN THE WAKE OF THE FRONT DURING THE LATE
OVERNIGHT AND EARLY MORNING HOURS ON THURSDAY...HOWEVER...EXPECT
DRIER AIR TO FILTER IN BEHIND THE FRONT AND THUS NOT TOO SURE
WHETHER THE LOWER CIGS WILL REMAIN SCT OR GO BKN-OVC...THEREFORE
HAVE MAINTAINED TRENDS FOR KSTL AT THIS TIME. OTHERWISE...GUSTY
WINDS TODAY WILL DIMINISH AFTER SUNSET...AND THOUGH WINDS WILL
REMAIN AOA 12KT OVERNIGHT...DO NOT EXPECT IT TO BE AS GUSTY ON
THURSDAY IN THE WAKE OF THE FRONT.
JP
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
630 AM CDT WED JUN 12 2013
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 337 AM CDT WED JUN 12 2013
MAIN CONCERN DEALS WITH POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON
INTO THE EVENING HOURS OVER PARTS OF THE CWA IF THUNDERSTORMS ARE
ABLE TO DEVELOP. IF THUNDERSTORMS DO DEVELOP...THEN THEY WILL
LIKELY BE SEVERE...PARTICULARLY OVER NORTHEAST MISSOURI INTO CENTRAL
ILLINOIS WITH DAMAGING WIND GUSTS IN EXCESS OF 70 MPH...LARGE HAIL
AND ISOLATED TORNADOES.
EXPECT MAINLY DRY CONDITIONS THROUGH THE MORNING HOURS AS THE
THUNDERSTORM COMPLEX CURRENTLY OVER WESTERN IOWA STAYS NORTH OF THE
AREA PER THE RAP FORWARD PROPAGATION VECTORS. OBSERVED AND FORECAST
SOUNDINGS STILL SHOW A VERY PRONOUNCED WARM LAYER BETWEEN 900-650MB
THROUGH LATE AFTERNOON WHICH SHOULD LIMIT THUNDERSTORM DEVELOPMENT.
THEREAFTER...THE TAIL END OF THE TROUGH CURRENTLY OVER THE HIGH
PLAINS WILL REACH THE MISSISSIPPI RIVER WHICH WILL ACT TO WEAKEN
THIS WARM LAYER AS THE ATTENDANT COLD FRONT MOVES SOUTHEAST ACROSS
THE CWA. MOST MODEL SOUNDINGS STILL SHOW SOME CONVECTIVE INHIBITION
OR VERY NARROW POSITIVE CAPE UP TO 700MB WHICH MAY KEEP
THUNDERSTORMS NORTH AND EAST OF THE AREA. WITH THIS SAID...MID
LEVEL FORCING AND LOW LEVEL MOISTURE CONVERGENCE IS WORTH KEEPING
SCATTERED THUNDERSTORMS IN THE FORECAST LATE THIS AFTERNOON INTO THE
EVENING AS THE COLD FRONT MOVES ACROSS THE CWA. INSTABILITY AND
SHEAR PARAMETERS FAVOR SEVERE THUNDERSTORMS WITH LATE AFTERNOON
MLCAPES AROUND 3000 J/KG AND 0-6KM SHEAR OF 40-50KTS. RELATIVELY
DRY AIR BELOW 700MB FAVORS THE POTENTIAL FOR DAMAGING WINDS
GUSTS...AND THERE IS A LARGE AMOUNT OF CAPE BETWEEN -10 AND -30C
WHICH SUGGESTS THE POTENTIAL FOR LARGE HAIL. SHEAR IS LINEAR IN THE
LOWEST LEVELS...THOUGH 0-1KM SHEAR NEAR 25KTS SUGGESTS TORNADOES ARE
ALSO POSSIBLE.
DID NOT CHANGE FORECAST HIGHS TODAY AS CURRENT TEMPERATURES ARE IN
THE 70S AND THERE WILL BE DECENT MIXING UP TO 850MB TODAY WITH MORE
SUN THAN YESTERDAY.
BRITT
.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUN 12 2013
AFTERNOON/EVENING CONVECTION SHOULD BE EXITING THE AREA BY 06Z.
CANNOT RULE OUT A STRAY SHOWER OR STORM OUT AHEAD OF OR RIGHT ON THE
COLD FRONT AS IT PUSHES THROUGH EAST CENTRAL AND SOUTHEAST MISSOURI
AND SOUTHERN ILLINOIS. NORTHWEST FLOW WILL BRING COOLER AND DRIER
AIR WITH SURFACE DEWPOINTS DROPPING BACK INTO THE UPPER 50S AND
LOWER 60S. 850MB TEMPS ALSO DROP INTO THE LOW TO MID TEENS BEHIND
THE FRONT. MODELS HAVE BEEN CONSISTENTLY AMPLIFYING THE FLOW
THURSDAY INTO FRIDAY WITH A FULL LONGWAVE TROF OVER THE EAST COAST
AND THE UPPER LEVEL RIDGE BUILDING ACROSS THE GREAT PLAINS INTO THE
UPPER MIDWEST. THIS SHOULD KEEP THE LOW LEVEL RIDGE LOCKED IN
ACROSS THE MISSISSIPPI VALLEY AT LEAST THROUGH FRIDAY. SEASONABLY
COOL GUIDANCE TEMPS LOOK PRETTY REASONABLE WITH AFOREMENTIONED COOL
AND DRY RIDGE IN PLACE. THERE IS A SMALL CHANCE THAT INCREASING
WARM ADVECTION ON THE WESTERN PERIPHERY OF THE LOW LEVEL RIDGE MAY
PRODUCE ISOLATED SHOWERS OR STORMS FRIDAY OVER PARTS OF CENTRAL AND
NORTHEAST MISSOURI SO HAVE SOME SLIGHT CHANCE POPS IN THOSE AREAS.
THE WEEKEND IS LOOKING MORE AND MORE STORMY AS THE UPPER LEVEL RIDGE
BREAKS DOWN IN RESPONSE TO A SHORTWAVE WHICH IS PULLED NORTHEAST OUT
OF THE GULF OF MEXICO. THIS WAVE IS LIKELY TO HAVE QUITE A BIT OF
MOISTURE ASSOCIATED WITH IT. AM UNSURE WHAT THE POTENTIAL FOR
SEVERE WEATHER WILL BE AT THIS TIME...BUT IT DOES LOOK LIKE THERE
WILL BE THUNDERSTORMS ON AND OFF FROM SATURDAY AFTERNOON AT LEAST
THROUGH SUNDAY NIGHT OR MONDAY AND SOME LOCALLY HEAVY RAIN MAY BE
POSSIBLE. TUESDAY LOOKS DRIER AS THE WAVE MOVES EAST AND WEAK
RIDGING BUILDS BACK ACROSS THE MID MISSISSIPPI VALLEY. TEMPERATURES
THROUGH THE PERIOD LOOK TO BE NEAR NORMAL.
CARNEY
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 626 AM CDT WED JUN 12 2013
A COLD FRONT WILL MOVE SOUTHEAST ACROSS THE AREA LATE THIS AFTERNOON
INTO THIS EVENING. IF THUNDERSTORMS DO DEVELOP ALONG THE FRONT...
THEY WILL BE CAPABLE OF PRODUCING HAIL AND GUSTY WINDS...AS WELL
AS BRIEF MVFR/POSSIBLE IFR CONDITIONS. MOST LIKELY LOCATION FOR
THUNDERSTORMS WILL BE AT KUIN. OTHERWISE EXPECT DRY AND VFR
CONDITIONS WITH GUSTY SOUTHWEST WINDS WHICH COULD CAUSE CROSSWIND
PROBLEMS FOR SMALLER AIRCRAFT ON NORTHWEST-SOUTHEAST ORIENTED
RUNWAYS. MODEL GUIDANCE IS INDICATING THAT LOW MVFR/IFR CEILINGS
MAY DEVELOP LATE TONIGHT...THOUGH DO NOT HAVE ENOUGH CONFIDENCE TO
INCLUDE IN THIS SET OF TAFS.
SPECIFICS FOR KSTL...EXPECT DRY AND VFR CONDITIONS WITH GUSTY
SOUTHWEST WINDS LATE THIS MORNING AND AFTERNOON. THERE IS A CHANCE
OF THUNDERSTORMS BETWEEN 23-03Z...BUT CHANCE IS TOO LOW TO INCLUDE
IN THE TAF AT THIS POINT. MODEL GUIDANCE ALSO INDICATES THAT LOW
MVFR/IFR CEILINGS WILL MOVE INTO THE TERMINAL AFTER 09Z...THOUGH
CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE WITH THIS TAF ISSUANCE.
BRITT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
340 AM CDT WED JUN 12 2013
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 337 AM CDT WED JUN 12 2013
MAIN CONCERN DEALS WITH POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON
INTO THE EVENING HOURS OVER PARTS OF THE CWA IF THUNDERSTORMS ARE
ABLE TO DEVELOP. IF THUNDERSTORMS DO DEVELOP...THEN THEY WILL
LIKELY BE SEVERE...PARTICULARLY OVER NORTHEAST MISSOURI INTO CENTRAL
ILLINOIS WITH DAMAGING WIND GUSTS IN EXCESS OF 70 MPH...LARGE HAIL
AND ISOLATED TORNADOES.
EXPECT MAINLY DRY CONDITIONS THROUGH THE MORNING HOURS AS THE
THUNDERSTORM COMPLEX CURRENTLY OVER WESTERN IOWA STAYS NORTH OF THE
AREA PER THE RAP FORWARD PROPAGATION VECTORS. OBSERVED AND FORECAST
SOUNDINGS STILL SHOW A VERY PRONOUNCED WARM LAYER BETWEEN 900-650MB
THROUGH LATE AFTERNOON WHICH SHOULD LIMIT THUNDERSTORM DEVELOPMENT.
THEREAFTER...THE TAIL END OF THE TROUGH CURRENTLY OVER THE HIGH
PLAINS WILL REACH THE MISSISSIPPI RIVER WHICH WILL ACT TO WEAKEN
THIS WARM LAYER AS THE ATTENDANT COLD FRONT MOVES SOUTHEAST ACROSS
THE CWA. MOST MODEL SOUNDINGS STILL SHOW SOME CONVECTIVE INHIBITION
OR VERY NARROW POSITIVE CAPE UP TO 700MB WHICH MAY KEEP
THUNDERSTORMS NORTH AND EAST OF THE AREA. WITH THIS SAID...MID
LEVEL FORCING AND LOW LEVEL MOISTURE CONVERGENCE IS WORTH KEEPING
SCATTERED THUNDERSTORMS IN THE FORECAST LATE THIS AFTERNOON INTO THE
EVENING AS THE COLD FRONT MOVES ACROSS THE CWA. INSTABILITY AND
SHEAR PARAMETERS FAVOR SEVERE THUNDERSTORMS WITH LATE AFTERNOON
MLCAPES AROUND 3000 J/KG AND 0-6KM SHEAR OF 40-50KTS. RELATIVELY
DRY AIR BELOW 700MB FAVORS THE POTENTIAL FOR DAMAGING WINDS
GUSTS...AND THERE IS A LARGE AMOUNT OF CAPE BETWEEN -10 AND -30C
WHICH SUGGESTS THE POTENTIAL FOR LARGE HAIL. SHEAR IS LINEAR IN THE
LOWEST LEVELS...THOUGH 0-1KM SHEAR NEAR 25KTS SUGGESTS TORNADOES ARE
ALSO POSSIBLE.
DID NOT CHANGE FORECAST HIGHS TODAY AS CURRENT TEMPERATURES ARE IN
THE 70S AND THERE WILL BE DECENT MIXING UP TO 850MB TODAY WITH MORE
SUN THAN YESTERDAY.
BRITT
.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUN 12 2013
AFTERNOON/EVENING CONVECTION SHOULD BE EXITING THE AREA BY 06Z.
CANNOT RULE OUT A STRAY SHOWER OR STORM OUT AHEAD OF OR RIGHT ON THE
COLD FRONT AS IT PUSHES THROUGH EAST CENTRAL AND SOUTHEAST MISSOURI
AND SOUTHERN ILLINOIS. NORTHWEST FLOW WILL BRING COOLER AND DRIER
AIR WITH SURFACE DEWPOINTS DROPPING BACK INTO THE UPPER 50S AND
LOWER 60S. 850MB TEMPS ALSO DROP INTO THE LOW TO MID TEENS BEHIND
THE FRONT. MODELS HAVE BEEN CONSISTENTLY AMPLIFYING THE FLOW
THURSDAY INTO FRIDAY WITH A FULL LONGWAVE TROF OVER THE EAST COAST
AND THE UPPER LEVEL RIDGE BUILDING ACROSS THE GREAT PLAINS INTO THE
UPPER MIDWEST. THIS SHOULD KEEP THE LOW LEVEL RIDGE LOCKED IN
ACROSS THE MISSISSIPPI VALLEY AT LEAST THROUGH FRIDAY. SEASONABLY
COOL GUIDANCE TEMPS LOOK PRETTY REASONABLE WITH AFOREMENTIONED COOL
AND DRY RIDGE IN PLACE. THERE IS A SMALL CHANCE THAT INCREASING
WARM ADVECTION ON THE WESTERN PERIPHERY OF THE LOW LEVEL RIDGE MAY
PRODUCE ISOLATED SHOWERS OR STORMS FRIDAY OVER PARTS OF CENTRAL AND
NORTHEAST MISSOURI SO HAVE SOME SLIGHT CHANCE POPS IN THOSE AREAS.
THE WEEKEND IS LOOKING MORE AND MORE STORMY AS THE UPPER LEVEL RIDGE
BREAKS DOWN IN RESPONSE TO A SHORTWAVE WHICH IS PULLED NORTHEAST OUT
OF THE GULF OF MEXICO. THIS WAVE IS LIKELY TO HAVE QUITE A BIT OF
MOISTURE ASSOCIATED WITH IT. AM UNSURE WHAT THE POTENTIAL FOR
SEVERE WEATHER WILL BE AT THIS TIME...BUT IT DOES LOOK LIKE THERE
WILL BE THUNDERSTORMS ON AND OFF FROM SATURDAY AFTERNOON AT LEAST
THROUGH SUNDAY NIGHT OR MONDAY AND SOME LOCALLY HEAVY RAIN MAY BE
POSSIBLE. TUESDAY LOOKS DRIER AS THE WAVE MOVES EAST AND WEAK
RIDGING BUILDS BACK ACROSS THE MID MISSISSIPPI VALLEY. TEMPERATURES
THROUGH THE PERIOD LOOK TO BE NEAR NORMAL.
CARNEY
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1153 PM CDT TUE JUN 11 2013
VFR CONDITIONS ARE EXPECTED TO DOMINATE MUCH OF THE PERIOD. BOUTS
OF HIGH CLOUDS WILL CONTINUE TO IMPACT EASTERN MO AND WESTERN
ILLINOIS INTO WED MORNING. SOUTH SOUTHWESTERLY SURFACE WINDS WILL
THEN INCREASE AROUND MID-MORNING ON WEDNESDAY WITH GUSTS AOA 25
KTS. THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS
PORTIONS OF NE MO AND WEST CENTRAL IL DURING THE LATER PART OF
WEDNESDAY AFTERNOON AND INTO THE EARLY EVENING AS A COLD FRONT
DROPS SOUTH INTO THE AREA. CONFIDENCE AT THIS TIME IS TOO LOW FOR
AN ACTUAL AIRPORT IMPACT TO INCLUDE IN THE KUIN TAF.
SPECIFICS FOR KSTL...
VFR CONDITIONS ARE EXPECTED TO DOMINATE MUCH OF THE PERIOD WITH
BOUTS OF HIGH CLOUDS CONTINUING OVERNIGHT THROUGH WEDNESDAY
MORNING. SOUTH SOUTHWESTERLY SURFACE WINDS WILL THEN INCREASE
AROUND MID-MORNING ON WEDNESDAY WITH GUSTS AOA 25 KTS. A COLD
FRONT WILL BE DROPPING INTO EASTERN MO ON WEDNESDAY EVENING AND IT
COULD BE ACCOMPANIED BY SCATTERED THUNDERSTORMS. IF THERE IS ANY
IMPACT AT KSTL...CURRENT INDICATIONS ARE THAT 04-07Z WOULD BE THE
OPTIMAL TIME FRAME...HOWEVER CONFIDENCE IS TOO LOW TO MENTION AT
THIS TIME.
GLASS
&&
.PRELIMINARY POINT TEMPS/POPS...
SAINT LOUIS 96 70 86 65 / 30 40 5 5
QUINCY 92 64 81 60 / 50 40 0 5
COLUMBIA 95 68 84 64 / 10 20 0 10
JEFFERSON CITY 96 69 84 65 / 10 10 0 10
SALEM 95 70 82 61 / 30 50 5 0
FARMINGTON 95 68 84 60 / 10 30 5 5
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
312 PM MDT WED JUN 12 2013
.SHORT TERM...VALID FOR THU AND FRI...
OVERVIEW...A FETCH OF MOISTURE CONTINUES TO STREAM OVER OUR
FORECAST AREA. THIS IS DUE TO SW FLOW ALOFT TAPPING INTO PACIFIC
MOISTURE AHEAD OF AN APPROACHING LONG WAVE TROUGH ON THE PACIFIC
NW COAST. IN THE LOWER LEVELS EASTERLY FLOW CONTINUES AND HAS KEPT
HIGH DEWPOINTS OVER THE REGION.
SO WE HAVE THE MOISTURE AND EFFECTIVE SHEAR NECESSARY FOR STRONG
THUNDERSTORMS TODAY. RAP MODEL PROGGS INDICATE AN AXIS OF
INSTABILITY FROM THE FRONT RANGE OF NORTH CENTRAL MONTANA DOWN TO
SHERIDAN COUNTY IN WYOMING THIS AFTERNOON AND INTO THE EARLY
EVENING. THIS AXIS IS WHERE I EXPECT STORMS TO REALLY FIRE UP
WITH SUSTAINED UPDRAFTS LATER TODAY. THE MAIN TRIGGER IS SOME
SUBTLE ENERGY NOW IN EASTERN IDAHO MOVING NORTHEAST ASSOCIATED
WITH A JETLET IN THE SW FLOW ALOFT. THIS FEATURE WILL NOT BE AS
STRONG AS YESTERDAYS SHORT WAVE TROUGH...BUT ADEQUATE TO GET
THINGS GOING. MY FEELING IS THE POTENTIAL FOR REACHING SEVERE
LIMITS WITH STORMS TODAY HAS BEEN DEGRADED BY THE CLOUD COVER.
ANALYSIS INDICATES THE EASTERN ZONES NEAR THE BORDER ARE PRETTY
WELL CAPPED AND WILL LIKELY STAY THAT WAY THROUGH AT LEAST THE
AFTERNOON. THE CENTRAL ZONES...INCLUDING BILLINGS...WHERE THE
INSTABILITY AXIS EXISTS HAS NOT BEEN ABLE TO HEAT UP MUCH YET
EITHER. SOME OF THE SREF SEVERE WEATHER INDICES ARE THUS BACKING
OFF A BIT ON THE POTENTIAL FOR SEVERE STORMS IN OUR AREA. SO MY
CONFIDENCE HAS DECREASED IN A WIDESPREAD SEVERE WEATHER EVENT FOR
OUR FORECAST AREA TODAY. THE WESTERN ZONES HAVE THE BEST CHANCE OF
SEEING STRONG TO SEVERE STORMS DUE TO THEIR WARMER SURFACE TEMPS
AND PROXIMITY TO SHORT WAVE ENERGY. THAT SAID...SHOWERS AND
THUNDERSTORMS STILL LOOK LIKE A GOOD BET FOR THE WESTERN AND
CENTRAL ZONES THROUGH EVENING...JUST NOT AS STRONG AS YESTERDAY.
ALSO...WITH OUR PRECIP WATER VALUES NEAR AN INCH OR MORE HEAVY
RAIN IS STILL QUITE POSSIBLE. THE FLASH FLOOD WATCHES ACROSS OUR
AREA ARE THUS IN GOOD SHAPE...WITH THE PINE CREEK BURN SCAR AND
MUSSELSHELL COUNTY BURN SCARS GENERALLY THE MOST UNDER THE GUN
THIS EVENING.
THURSDAY...THE UPPER TROUGH OFF THE PACIFIC NW COAST MOVES INTO
THE NORTHERN ROCKIES AND WILL DRIVE A MID LEVEL FRONT ACROSS OUR
REGION BY EVENING. THE MODELS HOLD MOST OF THE CONVECTION OUT OF
OUR AREA UNTIL EVENING...THEN SWEEP A STRONG WIND SHIFT OVER
SOUTHERN MONTANA. INGREDIENTS ARE THERE FOR HAIL AND WIND THREATS
MAINLY EAST OF A ROUNDUP TO BROADUS LINE.
FRIDAY...STRONG WESTERLY FLOW OVER THE AREA WILL DRY OUT THE
ATMOSPHERE. THE TROUGH WILL BE PASSING OVER WITH COOL MID LEVELS
LIMITING OUR AFTERNOON HIGHS. HAVE LOWERED TEMPS FOR FRIDAY A BIT.
BT
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
A QUIET WEATHER PATTERN IS EXPECTED FOR THE UPCOMING WEEKEND. A
COLD FRONT WILL MOVE THROUGH THE FORECAST AREA FRIDAY AS AN UPPER
LOW MOVES ACROSS SOUTHERN CANADA. THE FRONT WILL USHER IN DRIER
AIR FOR SATURDAY ALONG WITH BREEZY WESTERLY SURFACE WINDS. A
WEAKER FRONT DROPS DOWN FROM NORTHERN MONTANA LATE SATURDAY NIGHT
INTO SUNDAY MORNING BRINGING LIGHT NORTH TO NORTHEAST WINDS.
HOWEVER...NOT MUCH IF ANY MOISTURE LOOKS TO BE ASSOCIATED WITH
THIS FRONT AND GIVEN DRIER WEST TO NORTHWEST SURFACE FLOW...NOT
LOOKING FOR ANY SHOWER/THUNDERSTORM ACTIVITY AT THIS TIME. HIGH
PRESSURE RIDGING BEGINS TO BUILD SUNDAY INTO MONDAY. HOWEVER...A
FEW WEAK DISTURBANCES MAY UNDERCUT THIS RIDGE RESULTING IN A
SLIGHT SHOWER/THUNDERSTORM CHANCE MAINLY OVER AND NEAR THE
MOUNTAINS.
BY TUESDAY INTO WEDNESDAY...MODELS BRING ANOTHER UPPER LOW ONTO
THE PACIFIC NORTHWEST COAST BRINGING AN UNSETTLED SOUTHWEST FLOW
ALOFT TO THE FORECAST AREA. SEVERAL DISTURBANCES WITHIN THIS FLOW
WILL ALSO MOVE ACROSS OUR FORECAST AREA BRINGING RETURNED
THUNDERSTORM CHANCES. HOOLEY
&&
.AVIATION...
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE THIS
AFTERNOON MAINLY ALONG AND WEST OF A ROUNDUP-BILLINGS-SHERIDAN
LINE WITH THE ACTIVITY DEVELOPING EAST OF THIS LINE BY LATE THIS
AFTERNOON. THE THUNDERSTORMS WILL CONTAIN VERY HEAVY RAINFALL
ALONG WITH THE POSSIBILITY OF LARGE HAIL AND STRONG WIND GUSTS IN
EXCESS OF 50KTS. EXPECT MVFR TO LIFR CONDITIONS IN AND NEAR THE
THUNDERSTORM ACTIVITY. THE THUNDERSTORMS WILL BEGIN TO DIMINISH
LATE THIS EVENING. MOUNTAIN OBSCURATIONS WILL BE LIKELY THROUGH
THIS AFTERNOON AND INTO THE OVERNIGHT HOURS. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
THU FRI SAT SUN MON TUE WED
-----------------------------------------------------------
BIL 057/083 052/072 048/078 051/079 052/080 055/085 052/077
62/T 63/T 10/U 01/U 12/T 22/T 12/T
LVM 049/078 043/066 043/078 043/079 045/081 046/084 049/075
64/T 54/T 20/U 01/U 12/T 22/T 22/T
HDN 056/085 052/073 048/078 050/080 051/080 056/088 052/081
62/T 63/T 10/U 11/U 12/T 22/T 12/T
MLS 057/085 055/074 051/078 053/079 053/078 055/084 057/082
22/T 83/T 10/U 11/U 12/T 22/T 22/T
4BQ 054/089 054/073 049/078 050/080 051/079 055/087 055/087
22/T 52/T 10/U 11/U 12/T 22/T 11/U
BHK 053/079 056/072 049/076 050/075 050/075 054/080 058/079
32/T 52/W 10/U 11/U 12/T 22/T 11/U
SHR 052/086 050/072 044/078 047/078 049/079 053/086 050/085
42/T 52/T 10/U 11/U 12/T 22/T 12/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...SEVERE THUNDERSTORM WATCH 299 IN EFFECT UNTIL 10 PM MDT THIS
EVENING FOR ZONES 28-34-40>42-63>68.
FLASH FLOOD WATCH IN EFFECT UNTIL MIDNIGHT MDT TONIGHT FOR
ZONES 29-31-34-36>38-42-57-58-64-65-67.
WY...FLASH FLOOD WATCH IN EFFECT UNTIL MIDNIGHT MDT TONIGHT FOR
ZONE 99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS OMAHA/VALLEY NE
920 PM CDT THU JUN 13 2013
.UPDATE...
BAND OF PCPN THAT WAS MOVING THROUGH THE AREA THIS AFTERNOON AND
EARLY EVENING HAS MOVED EAST OF THE FORECAST AREA AS OF 9 PM SO
CLEANED UP ZFP WORDING FOR THAT. EXPECT THAT PCPN WILL PROBABLY
HOLD OFF MOST AREAS OVERNIGHT...BUT SOME CHANCE BY 3-4 AM CDT.
01Z HIGH RESOLUTION RAP AND 00Z NAM INDICATE THIS TREND. MADE A
FEW MINOR CHANGES TO POPS IN THE MORNING. OTHERWISE FEW IF ANY
CHANGES MADE BEYOND THE TONIGHT PERIOD.
MILLER
&&
.PREV DISCUSSION... /ISSUED 615 PM CDT THU JUN 13 2013/
AVIATION...
00Z TAFS FOR KOMA...KLNK...KOFK.
VFR CONDITIONS ARE STILL EXPECTED THROUGH MOST OF THE TAF PERIOD.
BAND OF SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE
EAST ACROSS WESTERN IOWA THIS EVENING...AWAY FROM THE TAF SITES.
SOME NEW ACTIVITY IS POSSIBLE LATE TONIGHT. HIGHEST CHANCES APPEAR
TO BE AT THE KOFK SITE...ESPECIALLY FROM 08Z TO 12Z. THERE COULD
STILL BE SOME ACTIVITY AFTER THAT...BUT DID NOT MENTION FOR NOW.
INCLUDED PROB 30 GROUPS FOR LATE TONIGHT INTO FRIDAY MORNING
AT KOMA AND KLNK. CEILINGS ARE LIKELY BE BE MAINLY ABOVE 3000 FT
BUT MVFR CONDITIONS POSSIBLE IN TSRA.
MILLER
PREV DISCUSSION... /ISSUED 308 PM CDT THU JUN 13 2013/
DISCUSSION...
THUNDERSTORM COMPLEX...INITIALLY PROBABLY ROOTED NEAR 600 MB PER
LBF/OAX 12Z SOUNDINGS...CONTINUED WORKING INTO FORECAST AREA THIS
AFTERNOON DESPITE LACK OF LOW LEVEL JET/INSTABILITY SUPPORT. THIS
HIGHLIGHTS UNCERTAINTIES THAT WILL EXIST IN FINE-TUNING
THUNDERSTORM CHCS AND TIMES THROUGH THIS WEEKEND AND IS THE
PRIMARY FORECAST CONCERN.
CURRENT RADAR TRENDS/LATEST RAP FCST WOULD TAKE THIS AREA OF
CONVECTION OUT OF ERN ZONES BY AROUND 02Z WITH A PROBABLE PRECIP
LULL UNTIL CONVECTION DEVELOPING TO OUR WEST APPROACHES OR
DEVELOPS INTO ZONES LATER TONIGHT. MADE SOME ATTEMPTS AT
ADJUSTING HOURLY GRIDS TO REFLECT THIS TREND TONIGHT.
HOWEVER...AFTER THAT RELUCTANT TO REMOVE OR LOWER TOMORROW MORNING
POPS VERY MUCH...ESPECIALLY CNTRL/NE ZONES AS 00Z/12Z ECMWF AND
12Z GFS CONTINUED TO DEVELOP QPF OVER THE NERN FA IN 12-18Z PD.
SINCE THIS AREA WILL BE ON NOSE OF THE MOISTURE/INSTABILITY RETURN
NOTED BY STRONG H85 THETA E ADVECTION IN 12Z-15Z PERIOD PER
NAM...LEFT IN LIKELY MORNING POPS NERN ZONES. ALTHOUGH THERE COULD
BE A MIDDAY LULL IN THE ACTIVITY...THIS THETA ADVECTION INCREASES
AGAIN IN THE AFTERNOON. THUS CANNOT REALLY SAY WHETHER OR NOT
CONVECTION WILL COMPLETELY DIE OUT...WHICH HAS BEEN THE CASE TODAY
AND WAS A FEW DAYS AGO AS WELL. SFC BASED DWPT RETURN PER NAM/GFS
PROBABLY TOO HIGH THUS SFC BASED CAPE FORECAST ALSO TOO HIGH
FRIDAY...BUT WITH BOUNDARY IN AREA AND UPPER WAVE LIFTING INTO
NERN MT...SOME SEVERE THREAT WILL PROBABLY EXIST. HOWEVER...
COVERAGE PROBABLY DICTATED BY EFFECTIVENESS OF CAP WHICH WILL BE
TRYING TO BECOME ESTABLISHED...ESPECIALLY SRN ZONES...OR DEBRIS
CLOUDS/PCPN FROM ANY MORNING ACTIVITY NE. AT THIS TIME MADE
LITTLE/NO CHANCES TO MAX TEMPS WHICH WILL LIKELY NEED ADJUSTING AS
AMOUNT OF DEBRIS BECOMES APPARENT.
WITH BOUNDARY REMAINING OVER AREA SATURDAY AND POSSIBLY SUNDAY...
AND CNTRL PLAINS CONTINUING ON SRN END OF WESTERLIES OF SRN
CANADIAN LOW...MODESTLY HIGH POPS WARRANTED INTO SUNDAY. ALTHOUGH
AGAIN WOULD GENERALLY THINK CENTROID OF MCS ACTIVITY ON SYNOPTIC
SCALE COULD SHIFT SOUTH EACH DAY THUS HIGHER CHCS WOULD APPEAR TO
SHIFT INTO SRN ZONES BY SUNDAY/SUNDAY NIGHT. WITH ERLY FLOW
SETTING UP SATURDAY BEHIND EXPECTED MCS TOMORROW NIGHT...LEANED
TOWARD COOLER NAM FOR MAX TEMPS. NO CHANGES TO SUNDAY MAX TEMPS AT
THIS TIME.
DRIER WEATHER STILL ON TAP MONDAY AND PROBABLY TUESDAY AS WELL AS
NWRLY FLOW SENDS HIGH PRESSURE THROUGH ERN PLAINS AND FORECAST WAS
MOSTLY DRY. AFTER THAT...RETURNING MOISTURE WILL BRING INCREASING
TSTM RISK THRU END OF WEEK ALTHOUGH FOR THE TIME BEING KEPT MOST
POPS IN LOWER CHC RANGE.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
615 PM CDT THU JUN 13 2013
.AVIATION...
00Z TAFS FOR KOMA...KLNK...KOFK.
VFR CONDITIONS ARE STILL EXPECTED THROUGH MOST OF THE TAF PERIOD.
BAND OF SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE
EAST ACROSS WESTERN IOWA THIS EVENING...AWAY FROM THE TAF SITES.
SOME NEW ACTIVITY IS POSSIBLE LATE TONIGHT. HIGHEST CHANCES APPEAR
TO BE AT THE KOFK SITE...ESPECIALLY FROM 08Z TO 12Z. THERE COULD
STILL BE SOME ACTIVITY AFTER THAT...BUT DID NOT MENTION FOR NOW.
INCLUDED PROB 30 GROUPS FOR LATE TONIGHT INTO FRIDAY MORNING
AT KOMA AND KLNK. CEILINGS ARE LIKELY BE BE MAINLY ABOVE 3000 FT
BUT MVFR CONDITIONS POSSIBLE IN TSRA.
MILLER
&&
.PREV DISCUSSION... /ISSUED 308 PM CDT THU JUN 13 2013/
DISCUSSION...
THUNDERSTORM COMPLEX...INITIALLY PROBABLY ROOTED NEAR 600 MB PER
LBF/OAX 12Z SOUNDINGS...CONTINUED WORKING INTO FORECAST AREA THIS
AFTERNOON DESPITE LACK OF LOW LEVEL JET/INSTABILITY SUPPORT. THIS
HIGHLIGHTS UNCERTAINTIES THAT WILL EXIST IN FINE-TUNING
THUNDERSTORM CHCS AND TIMES THROUGH THIS WEEKEND AND IS THE
PRIMARY FORECAST CONCERN.
CURRENT RADAR TRENDS/LATEST RAP FCST WOULD TAKE THIS AREA OF
CONVECTION OUT OF ERN ZONES BY AROUND 02Z WITH A PROBABLE PRECIP
LULL UNTIL CONVECTION DEVELOPING TO OUR WEST APPROACHES OR
DEVELOPS INTO ZONES LATER TONIGHT. MADE SOME ATTEMPTS AT
ADJUSTING HOURLY GRIDS TO REFLECT THIS TREND TONIGHT.
HOWEVER...AFTER THAT RELUCTANT TO REMOVE OR LOWER TOMORROW MORNING
POPS VERY MUCH...ESPECIALLY CNTRL/NE ZONES AS 00Z/12Z ECMWF AND
12Z GFS CONTINUED TO DEVELOP QPF OVER THE NERN FA IN 12-18Z PD.
SINCE THIS AREA WILL BE ON NOSE OF THE MOISTURE/INSTABILITY RETURN
NOTED BY STRONG H85 THETA E ADVECTION IN 12Z-15Z PERIOD PER
NAM...LEFT IN LIKELY MORNING POPS NERN ZONES. ALTHOUGH THERE COULD
BE A MIDDAY LULL IN THE ACTIVITY...THIS THETA ADVECTION INCREASES
AGAIN IN THE AFTERNOON. THUS CANNOT REALLY SAY WHETHER OR NOT
CONVECTION WILL COMPLETELY DIE OUT...WHICH HAS BEEN THE CASE TODAY
AND WAS A FEW DAYS AGO AS WELL. SFC BASED DWPT RETURN PER NAM/GFS
PROBABLY TOO HIGH THUS SFC BASED CAPE FORECAST ALSO TOO HIGH
FRIDAY...BUT WITH BOUNDARY IN AREA AND UPPER WAVE LIFTING INTO
NERN MT...SOME SEVERE THREAT WILL PROBABLY EXIST. HOWEVER...
COVERAGE PROBABLY DICTATED BY EFFECTIVENESS OF CAP WHICH WILL BE
TRYING TO BECOME ESTABLISHED...ESPECIALLY SRN ZONES...OR DEBRIS
CLOUDS/PCPN FROM ANY MORNING ACTIVITY NE. AT THIS TIME MADE
LITTLE/NO CHANCES TO MAX TEMPS WHICH WILL LIKELY NEED ADJUSTING AS
AMOUNT OF DEBRIS BECOMES APPARENT.
WITH BOUNDARY REMAINING OVER AREA SATURDAY AND POSSIBLY SUNDAY...
AND CNTRL PLAINS CONTINUING ON SRN END OF WESTERLIES OF SRN
CANADIAN LOW...MODESTLY HIGH POPS WARRANTED INTO SUNDAY. ALTHOUGH
AGAIN WOULD GENERALLY THINK CENTROID OF MCS ACTIVITY ON SYNOPTIC
SCALE COULD SHIFT SOUTH EACH DAY THUS HIGHER CHCS WOULD APPEAR TO
SHIFT INTO SRN ZONES BY SUNDAY/SUNDAY NIGHT. WITH ERLY FLOW
SETTING UP SATURDAY BEHIND EXPECTED MCS TOMORROW NIGHT...LEANED
TOWARD COOLER NAM FOR MAX TEMPS. NO CHANGES TO SUNDAY MAX TEMPS AT
THIS TIME.
DRIER WEATHER STILL ON TAP MONDAY AND PROBABLY TUESDAY AS WELL AS
NWRLY FLOW SENDS HIGH PRESSURE THROUGH ERN PLAINS AND FORECAST WAS
MOSTLY DRY. AFTER THAT...RETURNING MOISTURE WILL BRING INCREASING
TSTM RISK THRU END OF WEEK ALTHOUGH FOR THE TIME BEING KEPT MOST
POPS IN LOWER CHC RANGE.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1228 PM CDT WED JUN 12 2013
.AVIATION...
18Z TAFS FOR KOFK...KOMA AND KLNK.
VFR CIGS AND VSBYS EXPECTED BUT GUSTY NORTHWEST WINDS WILL OCCUR
DURING THE DAYLIGHT HOURS TODAY. NORTHWEST WINDS WILL LIKELY GUST
TO NEAR 30 KNOTS BEFORE SUNSET...THEN RAPIDLY DIMINISH. ANY
LINGERING CLOUDS WILL ALSO DISSIPATE AFTER DARK AS HIGH PRESSURE
BUILDS INTO THE REGION. THE MORNING HOURS SHOULD HAVE CLEAR SKIES
AND LIGHT WINDS.
NIETFELD
&&
.PREV DISCUSSION... /ISSUED 242 AM CDT WED JUN 12 2013/
DISCUSSION...
LOW PRESSURE WAS LOCATED OVER SOUTH CENTRAL NEBRASKA AT 07Z
WITH A COLD FRONT TRAILING INTO WESTERN KANSAS AND A WARM FRONT
EXTENDING ACROSS SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. CONVECTION
WAS ONGOING OVER EASTERN NEBRASKA INTO WEST CENTRAL AND NORTHWEST
IOWA.
LATEST HRRR MODEL TRACKS THE SURFACE LOW EAST TOWARD SOUTHWEST
IOWA THIS MORNING WITH THE COLD FRONT MOVING THROUGH THE AREA BY
18Z. CURRENT CONVECTION IS EXPECTED TO PUSH EAST OF THE AREA BY
THIS SAME TIME IN ADVANCE OF THE LOW AND NORTH OF THE WARM FRONT.
HIGH PRESSURE THEN BUILDS INTO THE PLAINS REGION THIS AFTERNOON
AND TONIGHT. AS THE HIGH MOVES EAST INTO THE MISSISSIPPI VALLEY
ON THURSDAY SOUTHERLY FLOW RETURNS TO THE PLAINS ALONG WITH A WARM
ADVECTION PATTERN AND THE CHANCE OF THUNDERSTORMS FOR THURSDAY
NIGHT INTO FRIDAY MORNING. AS ANOTHER STRONG UPPER WAVE MOVES INTO
THE NORTHERN PLAINS ON FRIDAY A COLD FRONT MOVES INTO THE AREA
AGAIN FRIDAY NIGHT WITH ANOTHER CHANCE OF STORMS FOR THE AREA.
EXTENDED MODELS STILL SHOW SOME POTENTIAL FOR ADDITIONAL STORMS
SATURDAY INTO SUNDAY. WITH THE UPPER PATTERN REMAINING STRONG AND
ACTIVE THROUGH MID WEEK PERIODS OF STORMS STILL INDICATED FOR THE
AREA DURING THIS TIME.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
631 AM CDT WED JUN 12 2013
.AVIATION...12Z TAFS FOR KOFK...KLNK AND KOMA.
VFR CONDITIONS ARE EXPECTED THROUGH THURSDAY MORNING. HIGH
PRESSURE BUILDING IN BEHIND AN EXITING LOW PRESSURE SYSTEM WILL
BRING GUSTY NORTHWEST WINDS OF 15 TO 25KT THROUGH THE DAY. THOSE
WINDS WILL SUBSIDE THIS EVENING. SCATTERED TO BROKEN CLOUDS NEAR
FL040 ARE LIKELY DURING THE AFTERNOON BUT SHOULD ALSO DISSIPATE AT
SUNSET.
DERGAN
&&
.PREV DISCUSSION... /ISSUED 242 AM CDT WED JUN 12 2013/
DISCUSSION...
LOW PRESSURE WAS LOCATED OVER SOUTH CENTRAL NEBRASKA AT 07Z
WITH A COLD FRONT TRAILING INTO WESTERN KANSAS AND A WARM FRONT
EXTENDING ACROSS SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. CONVECTION
WAS ONGOING OVER EASTERN NEBRASKA INTO WEST CENTRAL AND NORTHWEST
IOWA.
LATEST HRRR MODEL TRACKS THE SURFACE LOW EAST TOWARD SOUTHWEST
IOWA THIS MORNING WITH THE COLD FRONT MOVING THROUGH THE AREA BY
18Z. CURRENT CONVECTION IS EXPECTED TO PUSH EAST OF THE AREA BY
THIS SAME TIME IN ADVANCE OF THE LOW AND NORTH OF THE WARM FRONT.
HIGH PRESSURE THEN BUILDS INTO THE PLAINS REGION THIS AFTERNOON
AND TONIGHT. AS THE HIGH MOVES EAST INTO THE MISSISSIPPI VALLEY
ON THURSDAY SOUTHERLY FLOW RETURNS TO THE PLAINS ALONG WITH A WARM
ADVECTION PATTERN AND THE CHANCE OF THUNDERSTORMS FOR THURSDAY
NIGHT INTO FRIDAY MORNING. AS ANOTHER STRONG UPPER WAVE MOVES INTO
THE NORTHERN PLAINS ON FRIDAY A COLD FRONT MOVES INTO THE AREA
AGAIN FRIDAY NIGHT WITH ANOTHER CHANCE OF STORMS FOR THE AREA.
EXTENDED MODELS STILL SHOW SOME POTENTIAL FOR ADDITIONAL STORMS
SATURDAY INTO SUNDAY. WITH THE UPPER PATTERN REMAINING STRONG AND
ACTIVE THROUGH MID WEEK PERIODS OF STORMS STILL INDICATED FOR THE
AREA DURING THIS TIME.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
242 AM CDT WED JUN 12 2013
.DISCUSSION...
LOW PRESSURE WAS LOCATED OVER SOUTH CENTRAL NEBRASKA AT 07Z
WITH A COLD FRONT TRAILING INTO WESTERN KANSAS AND A WARM FRONT
EXTENDING ACROSS SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. CONVECTION
WAS ONGOING OVER EASTERN NEBRASKA INTO WEST CENTRAL AND NORTHWEST
IOWA.
LATEST HRRR MODEL TRACKS THE SURFACE LOW EAST TOWARD SOUTHWEST
IOWA THIS MORNING WITH THE COLD FRONT MOVING THROUGH THE AREA BY
18Z. CURRENT CONVECTION IS EXPECTED TO PUSH EAST OF THE AREA BY
THIS SAME TIME IN ADVANCE OF THE LOW AND NORTH OF THE WARM FRONT.
HIGH PRESSURE THEN BUILDS INTO THE PLAINS REGION THIS AFTERNOON
AND TONIGHT. AS THE HIGH MOVES EAST INTO THE MISSISSIPPI VALLEY
ON THURSDAY SOUTHERLY FLOW RETURNS TO THE PLAINS ALONG WITH A WARM
ADVECTION PATTERN AND THE CHANCE OF THUNDERSTORMS FOR THURSDAY
NIGHT INTO FRIDAY MORNING. AS ANOTHER STRONG UPPER WAVE MOVES INTO
THE NORTHERN PLAINS ON FRIDAY A COLD FRONT MOVES INTO THE AREA
AGAIN FRIDAY NIGHT WITH ANOTHER CHANCE OF STORMS FOR THE AREA.
EXTENDED MODELS STILL SHOW SOME POTENTIAL FOR ADDITIONAL STORMS
SATURDAY INTO SUNDAY. WITH THE UPPER PATTERN REMAINING STRONG AND
ACTIVE THROUGH MID WEEK PERIODS OF STORMS STILL INDICATED FOR THE
AREA DURING THIS TIME.
&&
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
GOING TAF IN GOOD SHAPE...THUS NO SIGNIFICANT CHANGES MADE. AVN
CONCERNS STILL FOCUSED ON KOFK. AREA OF TSRA WAS MOVING INTO NERN
NEB ALONG A NEAR-STATIONARY SFC BNDRY. THIS HAVE MAINTAINED TEMP
GROUP IN ANTICIPATION OF CONVECTION MOVING THRU. HOWEVER...STORM
TRAJECTORY PER RADAR TRENDS THE LAST HOUR SUGGEST IT IS POSSIBLE TSRA
ACTIVITY COULD REMAIN JUST NE OF KOFK. DO NOT EXPECT ANY TSRA
ACTIVITY AT KOMA/KLNK. OTHERWISE...COLD FRONTAL PASSAGE WILL SWING
SFC WINDS TO THE NW LATER THIS MORNING WITH GUSTS 20-25KT THRU THE
AFTN HOURS.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
FOBERT/DEE
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1222 AM CDT WED JUN 12 2013
.SYNOPSIS...
ISSUED AT 300 PM CDT TUE JUN 11 2013
H5 ANALYSIS THIS MORNING...AS A RIDGE EXTENDING FROM
TEXAS...NORTH INTO THE EASTERN DAKOTAS. WEST OF THE RIDGE...A STRONG
SHORTWAVE WAS LOCATED OVER NORTHERN NEVADA WITH A CLOSED LOW NOTED
OFF THE COAST OF BRITISH COLUMBIA. WV IMAGERY AS OF 18Z HAS THE NRN
NEVADA SHORTWAVE...ENTERING FAR SWRN WYOMING. LIGHTNING STRIKES
AND CONVECTION HAS DEVELOPED ACROSS SWRN MT AND NWRN WYOMING IN
ADVANCE OF THIS FEATURE. AT THE SURFACE A FRONTAL BOUNDARY
EXTENDED FROM CENTRAL WYOMING...SE INTO NRN COLORADO...THEN EAST
INTO SRN NEBRASKA. ALONG AND SOUTH OF THIS BOUNDARY...TEMPERATURES
HAVE SURGED INTO THE UPPER 90S AND LOWER 100S. NORTH OF THE
BOUNDARY...TEMPERATURES WERE IN 80S. DEEP EASTERLY FLOW WAS
PRESENT NORTH OF THE FRONT AND HAS PUSHED DEW POINTS INTO THE
UPPER 50S TO UPPER 60S THIS AFTERNOON...WITH THE HIGHEST DEW
POINTS NOTED OVER NORTHERN NEBRASKA. AS OF 2 PM CDT DEW
POINTS...RANGED FROM 63 AT PINE RIDGE...TO 68 AT ONEILL.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH WEDNESDAY)
ISSUED AT 300 PM CDT TUE JUN 11 2013
TONIGHT AND WEDNESDAY...MAIN FORECASTING CHALLENGE IS
THUNDERSTORM CHANCES AND SEVERE POTENTIAL TONIGHT. TOWARD 00Z THIS
EVENING...A DECENT SHORTWAVE WILL APPROACH THE PANHANDLE WITH TSRA
INITIATION DURING THE 22Z TO 00Z TIME FRAME. THE HI RES RUC...AS
WELL AS THE 12Z NAM SOLN...DEVELOPS ISOLD TSRAS IN THE NERN
PANHANDLE...AND SWRN NEBRASKA AROUND 22Z THIS AFTERNOON. ACTIVITY IN
THE SWRN CWA SHEARS OFF AND DISSIPATES QUICKLY BY 01Z. FURTHER
NORTH...ACTIVITY IS EXPECTED TO PERSIST INTO THE EVENING HOURS...DUE
TO A COMBINATION OF BETTER SUPPORT ALOFT AND DEEPER...RICHER
BOUNDARY LAYER MOISTURE IN NORTHERN NEBRASKA...WHERE DEWPOINTS WILL
REACH THE MID 60S TO AROUND 70 BY THIS EVENING. A TORNADO THREAT
WILL EXIST INITIALLY IN THE NWRN CWA WITH DECENT DEEP LAYER
SHEAR...LOWERED LCL HTS...AND THE PRESENCE OF A WEAK LOW LEVEL
BOUNDARY. BASED ON THE LATEST HRRR AND 4KM WRF
SOLNS...SHERIDAN...AND WESTERN CHERRY COUNTIES HAVE THE HIGHEST RISK
OF SEEING A DISCRETE SUPERCELL...AND THUS THE HIGHEST TORNADO THREAT
EARLY THIS EVENING. THE TORNADO THREAT WILL DECREASE BY MID EVENING
AS A STRONG FAST MOVING MCS DEVELOPS OVER THE BLACK HILLS AND RACES
EAST OVERNIGHT. THE THREAT FOR STRONG DAMAGING WINDS WILL BE HIGHEST
ACROSS FAR NORTHERN NEBRASKA INTO THE OVERNIGHT AS THIS WILL BE ON
THE SRN PERIPHERY OF THE MCS. AS THE MCS TRACKS INTO SRN MN/NRN IA
OVERNIGHT TONIGHT...A COLD FRONT WILL DROP SOUTH INTO WESTERN AND
NORTH CENTRAL NEBRASKA...WITH HIGH PRESSURE BUILDING INTO NERN
NEBRASKA FOR WEDNESDAY. COOLER TEMPS AND PARTLY TO MOSTLY CLOUDY
SKIES WILL PUSH INTO NERN AND CENTRAL PORTIONS OF THE FORECAST AREA
WEDNESDAY WITH HIGHS RANGING FROM THE UPPER 70S TO MIDDLE 80S.
ACROSS FAR SWRN NEBRASKA...HIGHS WILL TOP OUT NEAR 90.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 300 PM CDT TUE JUN 11 2013
MODELS HAVE COME INTO BETTER AGREEMENT IN MID AND LONG TERM
FORECASTS. HEAT TO HANG AROUND WITH SUMMER BEGINNING EARLY. STRONG
RIDGE OVER SOUTHERN INTO NORTHERN PLAINS WILL KEEP JET STREAM WELL
NORTH. H5 SYSTEMS MOVING OUT OF THE GULF OF ALASKA WILL TRY TO
FLATTEN RIDGE OVER NORTHERN PLAINS BUT MAIN ENERGY WILL BE PUSHED
TO THE CANADIAN US BORDER WITH WEAKER WAVES MOVING UNDER THE
RIDGE. WITH AFTERNOON HEATING AND INSTABILITY INCREASING LATE
AFTERNOON THUNDERSTORMS FIRING ALONG THE FRONT RANGE AND MOVING
EAST INTO WESTERN NEBRASKA IN A RING OF FIRE PATTERN. NAM HAS BEEN
HANDLING HEAT FAR BETTER THAN OTHER MODELS AS OF LATE AND WILL
LEAN TOWARDS NAM SOLUTIONS AS FAR AS HIGH TEMPERATURES. SURFACE
HIGH PRESSURE BUILDING INTO WESTERN NEBRASKA WEDNESDAY EVENING. SOME
CLEARING HAVE KEPT TEMPERATURES IN THE MID TO UPPER 50S WITH 15C
850MB TEMPERATURES OVER HEAD. WARM AIR ADVECTION OVER WESTERN
NEBRASKA THROUGH THE DAY ON THURSDAY. UPSLOPE FLOW AND WAVE
MOVING THROUGH HAVE RETAINED POPS. FRIDAY LOOKS TO WARM UP INTO
THE 90S ONCE AGAIN WITH SOME WARMER TEMPERATURES OVER SOUTHWEST
NEBRASKA NEAR IMPERIAL. 850MB TEMPS 30C AND GREATER ONCE AGAIN.
THUNDERSTORMS TO LINGER INTO THE DAY ON FRIDAY WITH BOUNDARY LYING
ACROSS FORECAST AREA. WARM TEMPERATURES AT 700MB INDICATIVE OF
STRONG CAP AND POPS MAY HAVE TO BE REDUCED IN LATER FORECASTS.
EVEN WITH COOLER TEMPERATURES SATURDAY BEHIND FRONT BOUNDARY
CONTINUES TO LAY ACROSS FORECAST AREA AND STRONG MOISTURE
ADVECTION HAVE RETAINED THUNDERSTORMS LATE AFTERNOON AND EVENING.
THUNDERSTORMS IN THE FORECAST AGAIN ON SUNDAY AS SYSTEM DROPS OUT
OF CANADA ACROSS MINNESOTA. BETTER CHANCES OVER EASTERN PORTIONS
OF THE FORECAST AREA. NORMAL TEMPERATURES IN THE 80S THROUGH THE
FIRST PART OF THE WORK WEEK WITH CHANCES FOR THUNDERSTORMS MAINLY
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1221 AM CDT WED JUN 12 2013
STORMS ARE LIKELY TO CONTINUE IN NORTHERN NEBRASKA UNTIL ABOUT 09Z.
THERE IS ONLY A NARROW WINDOW...06-08Z...IN WHICH THE SOUTHWEST WILL
HAVE ANY CHANCE OF STORMS. AS A RESULT...WE HAVE LEFT THUNDER OUT OF
THE FORECAST FOR LBF...BUT LEFT A MENTION IN THE FORECAST FOR VTN.
AFTER 09Z...THERE IS AGAIN A POSSIBILITY OF PATCHY FOG IN THE LBF
AREA UNLESS DRIER AIR PUSHES IN AS IT DID LAST NIGHT. WITH WIND
CONTINUING OUT OF THE EAST TO NORTHEAST...I DO NOT EXPECT THE AIR TO
DRY OUT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...CLB
LONG TERM...POWER
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1220 AM CDT WED JUN 12 2013
.UPDATE...
ISSUED AT 1133 PM CDT TUE JUN 11 2013
UPDATED THE HWO TO REMOVE WIND ADVISORY AND HEAT INDEX WORDING. AS
OF 04Z KUEX AND KLNX INDICATED ISOLATED TO SCATTERED THUNDERSTORM
ACTIVITY OVER PORTIONS OF CENTRAL NEBRASKA...WITH MUCH OF THIS
ACTIVITY REMAINING JUST NORTHWEST OF OUR AREA. IN
ADDITION...INTENSE CONVECTION CONTINUES OVER THE NORTHERN HIGH
PLAINS. GUIDANCE CONTINUES TO SUGGEST AN INTENSE 850MB JET STREAK
OF 60-70KTS WILL SET UP OVER OUR AREA TONIGHT. THANKFULLY THIS LOW
LEVEL JET SHOULD SHIFT EAST...AWAY FROM OUR AREA DURING THE 06-12Z
TIME PERIOD...BUT THERE IS SOME CONCERN THE INTENSE CONVECTION TO
OUR NORTHWEST COULD LATCH ON TO THE AXIS OF LOW LEVEL THERMAL
ADVECTION ALONG THE LOW LEVEL JET THUS ALLOWING THE THUNDERSTORM
ACTIVITY TO SURGE INTO OUR AREA. CURRENT FORECAST ALREADY HAS ~20%
POPS ACROSS OUR CWA AND THIS SEEMS REASONABLE FOR THE TIME BEING.
THE EXTREMELY WARM LOW TO MID LEVEL WARM AIRMASS HAS PUSHED
FREEZING HEIGHTS CLOSE TO 15000FT AGL ACROSS MUCH OF OUR
AREA...THUS SUGGESTING AN UPDRAFT WOULD HAVE TO BE STRONG ENOUGH
TO PUSH A PRECIPITATION MASS CLOSE TO 40000FT AGL FOR SEVERE HAIL
TO BE REALIZED. AS A RESULT...HAIL IS NOT A PRIMARY CONCERN
TONIGHT. THAT BEING SAID...PROXIMITY SOUNDINGS FROM THE ACROSS OUR
CWA...PER LAPS AND RAP ANALYSIS...AS WELL AS 00Z SOUNDING DATA
FROM KBLF...SUGGEST A VERY DRY LOW TO MID TROPOSPHERIC AIRMASS IS
IN PLACE. MUCH LIKE LAST NIGHT...IF A PRECIPITATION MASS CAN
EFFECTIVELY COOL THROUGH EVAPORATION AND GAIN SIGNIFICANT MOMENTUM
TOWARDS THE SURFACE...A STRONG THUNDERSTORM WIND GUST WILL
CERTAINLY BE POSSIBLE. OBVIOUSLY...IF THE INTENSE CONVECTION OVER
THE NORTHERN HIGH PLAINS CAN SUSTAIN ITSELF DOWN THIS WAY...THEN
THERE WILL BE THE CHANCE OF AN QLCS WORKING ACROSS THE AREA WHICH
WILL CERTAINLY PROVIDE A THREAT FOR STRONG WIND. DO WANT TO
EMPHASIZE THAT ALL OF THESE THREATS ARE VERY MARGINAL AND THAT THE
OVERALL THE THREAT FOR SEVERE WEATHER SEEMS VERY LOW FOR
TONIGHT...BUT STILL SOMETHING TO CONTINUE MONITORING. OVERALL THE
GOING FORECAST FOR TONIGHT REMAINS IN GREAT SHAPE WITH NO
SIGNIFICANT CHANGES MADE AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 350 PM CDT TUE JUN 11 2013
AN UPPER LEVEL DISTURBANCE CROSSING THE INTERMOUNTAIN WEST THIS
AFTERNOON WILL CONTINUE TO TRANSITION AND CUT INTO THE UPPER LEVEL
RIDGE ON WEDNESDAY...HELPING TO STEER A WEAK COLD FRONT TO OUR NORTH
ACROSS THE LOCAL AREA OVERNIGHT TONIGHT. AS A RESULT...EXPECT
AFTERNOON TEMPERATURES TO FALL SIGNIFICANTLY ACROSS MUCH OF THE
LOCAL AREA ON WEDNESDAY...RETURNING TO NEAR OR JUST ABOVE
CLIMATOLOGICAL VALUES.
IN THE MEANTIME...ALREADY SEEING A COUPLE OF SHOWERS DEVELOP
ACROSS NORTHWESTERN KANSAS THIS AFTERNOON...WHICH ARE EXPECTED TO
SLOWLY DRIFT TOWARDS THE LOCAL AREA LATE THIS AFTERNOON AND
EVENING. WHILE A SIGNIFICANT CAP REMAINS IN PLACE...PLENTY OF
INSTABILITY EXISTS IF A FEW STORMS ARE ABLE TO DEVELOP FOR SOME
STRONG WIND GUSTS AND POSSIBLY MARGINALLY SEVERE HAIL...SOME OF
WHICH IS CAPTURED BY LATEST HRRR AND 12Z WRF. EVEN SO...THE BEST
CHANCE FOR DEVELOPMENT...SEVERE OR OTHERWISE...IS EXPECTED TO BE
ACROSS THE NORTHERN TIER OF COUNTIES OVERNIGHT...AS THIS AREA WILL
BE NEAR THE APPROACHING COLD FRONT AND IN THE AXIS OF THE
DEVELOPING LOW LEVEL JET. SO WHILE THE SEVERE POTENTIAL WILL BE
FOCUSED PRIMARILY WEST OF HIGHWAY 281 LATE THIS AFTERNOON AND
EARLY EVENING...EXPECT THUNDERSTORM POTENTIAL TO SHIFT NORTH
OVERNIGHT...WHERE A FEW OF OUR COUNTIES ARE HIGHLIGHTED IN SLIGHT
RISK FOR SEVERE WEATHER FROM SPC.
OTHERWISE...EXPECT A FAIRLY NICE...BUT BREEZY DAY...ACROSS THE
REGION ON WEDNESDAY...AS SKIES WILL CLEAR BEHIND THE PASSING FRONT
AND TEMPERATURES WILL BE SIGNIFICANTLY COOLER THAN THIS AFTERNOONS
VALUES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 350 PM CDT TUE JUN 11 2013
ALOFT: GLOBAL MODELS AND THEIR ENSEMBLES ARE IN EXCELLENT AGREEMENT
ON THE LONG-WAVE /LGWV/ FLOW THRU THE FCST PERIOD AND EVEN THRU DAY
10 /JUN 20TH/. THE GENERAL PATTERN WILL FEATURE A RIDGE OVER THE
PLAINS WITH TROFS ON BOTH COASTS. THE CLOSED LOW CURRENTLY MILLING
AROUND OFF BRITISH COLUMBIA WILL GET SLOWLY KICKED INTO THE PAC NW
WED-THU AND KNOCK DOWN THE RIDGE FRI-SAT BEFORE EMERGING INTO AND
DEEPENING THE ERN USA TROF. THIS WILL FORCE THE RIDGE TO RETROGRADE
INTO THE ROCKIES AS IT REBUILDS. THE INITIAL INDICATIONS ARE THAT
THE RIDGE WILL ADVANCE BACK INTO THE PLAINS THE MIDDLE OF NEXT WEEK
AS THE NEXT NE PAC LOW MOVES ONSHORE.
SFC: THE COOL FRONT MOVES THRU WED WILL SINK TO THE KS-OK BORDER BY
DAWN THU...WITH CANADIAN HIGH PRES BUILDING S INTO THE REGION. THE
ADVANCE OF THE UPR LOW AND THE PV ANOMALIES ORBITING IT WILL
INITIATE A NEW LEE LOW THU NGT...WITH THE FRONT LIFTING BACK N. THIS
WILL SPREAD THE 90+ HEAT BACK N INTO S-CNTRL NEB FRI. THE COOL FRONT
ASSOCIATED WITH THE ADVANCING PAC NW UPR LOW WILL ARRIVE HERE FRI
NGT AND WASH OUT. AS THE REMNANTS OF UPR LOW DROP INTO THE ERN USA
TROF EARLY NEXT WEEK...A MUCH STRONGER COOL FRONT WILL MOVE THRU SUN
NGT.
THE DAILY DETAILS...
THU: QUIET WITH TEMPS CLOSE TO NORMAL. COULD SEE AN EVNG SHWR/TSTM
DRIFT IN FROM NW KS OR WRN NEB.
THU NGT: COULD SEE AN MCS ROLL THRU HERE OR NEARBY AS LLJ PUNCHES
OVER THE LIFTING WARM FRONT.
FRI: HOT AND BREEZY IN THE WARM SECTOR. IF AN MCS OCCURS IT WILL
REINFORCE AND SLOW OR STALL THE WARM FRONT. TEMPS COULD BUST IF
COOL/CLOUDY CONDITIONS LINGER. THE WARM FRONT COULD ALSO BE A FOCUS
FOR RENEWED LATE DAY TSTM DEVELOPMENT.
FRI NGT: STRONG CONVERGENCE WITH PASSAGE OF COOL FRONT. THIS COULD
BE A DECENT OPPORTUNITY FOR TSTMS WHERE PARCELS CAN REACH THE LFC.
SAT-SUN: NEAR NORMAL TEMPS AND DRY MOST OF THE TIME. HOWEVER...
THERE WILL BE A RISK OF TSTMS EACH DAY...HIGHEST PROBABILITY BETWEEN
4PM-4AM. AT THIS POINT BELIEVE THE BEST CHANCE FOR ORGANIZED/
WIDESPREAD TSTMS WILL BE SUN AFTN-NGT.
MON: PROBABLY ENDS UP DRY AS AMPLIFYING ERN USA TROF WILL TAKE THE
COOL FRONT FARTHER S THAN ITS PREDECESSORS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1220 AM CDT WED JUN 12 2013
MAIN AREA OF THUNDERSTORMS REMAINS WELL TO THE NORTH OF THE KGRI
TERMINAL AREA BUT THERE HAVE BEEN SOME SHOWERS AND ISOLATED
THUNDERSTORMS THAT DEVELOPED TO THE WEST. THESE HAVE MAINLY
DISSIPATED AND DO NOT EXPECT ANYTHING AT THE KGRI TERMINAL. A
SURFACE LOW AND COLD FRONT TO THE WEST IS EXPECTED TO MOVE THROUGH
IN THE NEXT COUPLE HOURS AND GUSTY WINDS FROM THE SOUTH WILL GIVE
WAY TO NORTH WINDS. WINDS WILL INCREASE SOME DURING THE DAY
WEDNESDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...BRYANT
SHORT TERM...SAR
LONG TERM...HALBLAUB
AVIATION...JCB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1133 PM CDT TUE JUN 11 2013
.UPDATE...
ISSUED AT 1133 PM CDT TUE JUN 11 2013
UPDATED THE HWO TO REMOVE WIND ADVISORY AND HEAT INDEX WORDING. AS
OF 04Z KUEX AND KLNX INDICATED ISOLATED TO SCATTERED THUNDERSTORM
ACTIVITY OVER PORTIONS OF CENTRAL NEBRASKA...WITH MUCH OF THIS
ACTIVITY REMAINING JUST NORTHWEST OF OUR AREA. IN
ADDITION...INTENSE CONVECTION CONTINUES OVER THE NORTHERN HIGH
PLAINS. GUIDANCE CONTINUES TO SUGGEST AN INTENSE 850MB JET STREAK
OF 60-70KTS WILL SET UP OVER OUR AREA TONIGHT. THANKFULLY THIS LOW
LEVEL JET SHOULD SHIFT EAST...AWAY FROM OUR AREA DURING THE 06-12Z
TIME PERIOD...BUT THERE IS SOME CONCERN THE INTENSE CONVECTION TO
OUR NORTHWEST COULD LATCH ON TO THE AXIS OF LOW LEVEL THERMAL
ADVECTION ALONG THE LOW LEVEL JET THUS ALLOWING THE THUNDERSTORM
ACTIVITY TO SURGE INTO OUR AREA. CURRENT FORECAST ALREADY HAS ~20%
POPS ACROSS OUR CWA AND THIS SEEMS REASONABLE FOR THE TIME BEING.
THE EXTREMELY WARM LOW TO MID LEVEL WARM AIRMASS HAS PUSHED
FREEZING HEIGHTS CLOSE TO 15000FT AGL ACROSS MUCH OF OUR
AREA...THUS SUGGESTING AN UPDRAFT WOULD HAVE TO BE STRONG ENOUGH
TO PUSH A PRECIPITATION MASS CLOSE TO 40000FT AGL FOR SEVERE HAIL
TO BE REALIZED. AS A RESULT...HAIL IS NOT A PRIMARY CONCERN
TONIGHT. THAT BEING SAID...PROXIMITY SOUNDINGS FROM THE ACROSS OUR
CWA...PER LAPS AND RAP ANALYSIS...AS WELL AS 00Z SOUNDING DATA
FROM KBLF...SUGGEST A VERY DRY LOW TO MID TROPOSPHERIC AIRMASS IS
IN PLACE. MUCH LIKE LAST NIGHT...IF A PRECIPITATION MASS CAN
EFFECTIVELY COOL THROUGH EVAPORATION AND GAIN SIGNIFICANT MOMENTUM
TOWARDS THE SURFACE...A STRONG THUNDERSTORM WIND GUST WILL
CERTAINLY BE POSSIBLE. OBVIOUSLY...IF THE INTENSE CONVECTION OVER
THE NORTHERN HIGH PLAINS CAN SUSTAIN ITSELF DOWN THIS WAY...THEN
THERE WILL BE THE CHANCE OF AN QLCS WORKING ACROSS THE AREA WHICH
WILL CERTAINLY PROVIDE A THREAT FOR STRONG WIND. DO WANT TO
EMPHASIZE THAT ALL OF THESE THREATS ARE VERY MARGINAL AND THAT THE
OVERALL THE THREAT FOR SEVERE WEATHER SEEMS VERY LOW FOR
TONIGHT...BUT STILL SOMETHING TO CONTINUE MONITORING. OVERALL THE
GOING FORECAST FOR TONIGHT REMAINS IN GREAT SHAPE WITH NO
SIGNIFICANT CHANGES MADE AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 350 PM CDT TUE JUN 11 2013
AN UPPER LEVEL DISTURBANCE CROSSING THE INTERMOUNTAIN WEST THIS
AFTERNOON WILL CONTINUE TO TRANSITION AND CUT INTO THE UPPER LEVEL
RIDGE ON WEDNESDAY...HELPING TO STEER A WEAK COLD FRONT TO OUR NORTH
ACROSS THE LOCAL AREA OVERNIGHT TONIGHT. AS A RESULT...EXPECT
AFTERNOON TEMPERATURES TO FALL SIGNIFICANTLY ACROSS MUCH OF THE
LOCAL AREA ON WEDNESDAY...RETURNING TO NEAR OR JUST ABOVE
CLIMATOLOGICAL VALUES.
IN THE MEANTIME...ALREADY SEEING A COUPLE OF SHOWERS DEVELOP
ACROSS NORTHWESTERN KANSAS THIS AFTERNOON...WHICH ARE EXPECTED TO
SLOWLY DRIFT TOWARDS THE LOCAL AREA LATE THIS AFTERNOON AND
EVENING. WHILE A SIGNIFICANT CAP REMAINS IN PLACE...PLENTY OF
INSTABILITY EXISTS IF A FEW STORMS ARE ABLE TO DEVELOP FOR SOME
STRONG WIND GUSTS AND POSSIBLY MARGINALLY SEVERE HAIL...SOME OF
WHICH IS CAPTURED BY LATEST HRRR AND 12Z WRF. EVEN SO...THE BEST
CHANCE FOR DEVELOPMENT...SEVERE OR OTHERWISE...IS EXPECTED TO BE
ACROSS THE NORTHERN TIER OF COUNTIES OVERNIGHT...AS THIS AREA WILL
BE NEAR THE APPROACHING COLD FRONT AND IN THE AXIS OF THE
DEVELOPING LOW LEVEL JET. SO WHILE THE SEVERE POTENTIAL WILL BE
FOCUSED PRIMARILY WEST OF HIGHWAY 281 LATE THIS AFTERNOON AND
EARLY EVENING...EXPECT THUNDERSTORM POTENTIAL TO SHIFT NORTH
OVERNIGHT...WHERE A FEW OF OUR COUNTIES ARE HIGHLIGHTED IN SLIGHT
RISK FOR SEVERE WEATHER FROM SPC.
OTHERWISE...EXPECT A FAIRLY NICE...BUT BREEZY DAY...ACROSS THE
REGION ON WEDNESDAY...AS SKIES WILL CLEAR BEHIND THE PASSING FRONT
AND TEMPERATURES WILL BE SIGNIFICANTLY COOLER THAN THIS AFTERNOONS
VALUES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 350 PM CDT TUE JUN 11 2013
ALOFT: GLOBAL MODELS AND THEIR ENSEMBLES ARE IN EXCELLENT AGREEMENT
ON THE LONG-WAVE /LGWV/ FLOW THRU THE FCST PERIOD AND EVEN THRU DAY
10 /JUN 20TH/. THE GENERAL PATTERN WILL FEATURE A RIDGE OVER THE
PLAINS WITH TROFS ON BOTH COASTS. THE CLOSED LOW CURRENTLY MILLING
AROUND OFF BRITISH COLUMBIA WILL GET SLOWLY KICKED INTO THE PAC NW
WED-THU AND KNOCK DOWN THE RIDGE FRI-SAT BEFORE EMERGING INTO AND
DEEPENING THE ERN USA TROF. THIS WILL FORCE THE RIDGE TO RETROGRADE
INTO THE ROCKIES AS IT REBUILDS. THE INITIAL INDICATIONS ARE THAT
THE RIDGE WILL ADVANCE BACK INTO THE PLAINS THE MIDDLE OF NEXT WEEK
AS THE NEXT NE PAC LOW MOVES ONSHORE.
SFC: THE COOL FRONT MOVES THRU WED WILL SINK TO THE KS-OK BORDER BY
DAWN THU...WITH CANADIAN HIGH PRES BUILDING S INTO THE REGION. THE
ADVANCE OF THE UPR LOW AND THE PV ANOMALIES ORBITING IT WILL
INITIATE A NEW LEE LOW THU NGT...WITH THE FRONT LIFTING BACK N. THIS
WILL SPREAD THE 90+ HEAT BACK N INTO S-CNTRL NEB FRI. THE COOL FRONT
ASSOCIATED WITH THE ADVANCING PAC NW UPR LOW WILL ARRIVE HERE FRI
NGT AND WASH OUT. AS THE REMNANTS OF UPR LOW DROP INTO THE ERN USA
TROF EARLY NEXT WEEK...A MUCH STRONGER COOL FRONT WILL MOVE THRU SUN
NGT.
THE DAILY DETAILS...
THU: QUIET WITH TEMPS CLOSE TO NORMAL. COULD SEE AN EVNG SHWR/TSTM
DRIFT IN FROM NW KS OR WRN NEB.
THU NGT: COULD SEE AN MCS ROLL THRU HERE OR NEARBY AS LLJ PUNCHES
OVER THE LIFTING WARM FRONT.
FRI: HOT AND BREEZY IN THE WARM SECTOR. IF AN MCS OCCURS IT WILL
REINFORCE AND SLOW OR STALL THE WARM FRONT. TEMPS COULD BUST IF
COOL/CLOUDY CONDITIONS LINGER. THE WARM FRONT COULD ALSO BE A FOCUS
FOR RENEWED LATE DAY TSTM DEVELOPMENT.
FRI NGT: STRONG CONVERGENCE WITH PASSAGE OF COOL FRONT. THIS COULD
BE A DECENT OPPORTUNITY FOR TSTMS WHERE PARCELS CAN REACH THE LFC.
SAT-SUN: NEAR NORMAL TEMPS AND DRY MOST OF THE TIME. HOWEVER...
THERE WILL BE A RISK OF TSTMS EACH DAY...HIGHEST PROBABILITY BETWEEN
4PM-4AM. AT THIS POINT BELIEVE THE BEST CHANCE FOR ORGANIZED/
WIDESPREAD TSTMS WILL BE SUN AFTN-NGT.
MON: PROBABLY ENDS UP DRY AS AMPLIFYING ERN USA TROF WILL TAKE THE
COOL FRONT FARTHER S THAN ITS PREDECESSORS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 550 PM CDT TUE JUN 11 2013
WIND WILL BE TRICKY FOR THIS FORECAST AS A NEARLY STATIONARY FRONT
LIES JUST TO THE SOUTH...AFFECTING WIND DIRECTION AND SPEED. BEST
GUESS WILL BE A DIRECTION FROM THE SOUTHEAST AS THE TERMINAL
SHOULD BE JUST NORTH OF THE BOUNDARY...WITH A DECREASE SHORTLY
INTO THE FORECAST. A COLD FRONT SHOULD CHANGE THE WIND DIRECTION
LATE TONIGHT TO THE NORTH NORTHWEST AFTER A COLD FRONT COMES
THROUGH AND AN INCREASE TO WIND SPEEDS...ESPECIALLY AS MIXING
INCREASES. VFR CONDITIONS ARE ANTICIPATED AND ONLY A SLIGHT CHANCE
OF THUNDERSTORMS EXISTS FOR TONIGHT. WITH SUCH A LOW
CHANCE...THUNDERSTORMS WERE LEFT OUT OF THE FORECAST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...BRYANT
SHORT TERM...SAR
LONG TERM...HALBLAUB
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
314 PM MDT WED JUN 12 2013
.DISCUSSION...
NOT TOO MUCH CHANGE TO THE GOING FORECAST. TEMPERATURES CONTINUE TO
CREEP UP THIS AFTERNOON AREAWIDE. TEMPS ARE NOT AS QUICK TO RISE
TODAY THANKS TO A LITTLE CLOUD COVER ACROSS THE WEST AND NORTH AND
EAST TO SOUTHEASTERLY SURFACE WINDS ACROSS THE PLAINS. SATELLITE
IMAGERY SHOWING A NICE BUBBLING OF CU EXTENDING FROM THE SANGRE DE
CRISTOS SOUTHWARD TO THE SACRAMENTO MOUNTAINS. THIS WILL BE THE
FAVORED AREA FOR ANY LIGHT SHOWERS...VIRGA AND/OR DRY THUNDERSTORMS
THIS EVENING...THOUGH THE HRRR AND THE NAM WERE SHOWING A BIT OF QPF
ACROSS THE FAR NORTHEAST WHERE SOUTHEASTERLY FLOW IS CURRENTLY
BRINGING HIGHER DEWPOINTS UP ONTO THE RATON RIDGE. ANY ACTIVITY THAT
DEVELOPS SHOULD DIMINISH BY MIDNIGHT...IF NOT SHORTLY AFTER SUNSET.
ANOTHER WARM NIGHT IS IN STORE ACROSS THE EASTERN PLAINS. RECORD
HEAT FOR THURSDAY IS NOT EXPECTED TO BE AS WIDESPREAD. THE
COMBINATION OF AN UPPER LEVEL TROUGH ACROSS THE NORTHWEST CONUS AND
AND UPPER LEVEL DISTURBANCE MOVING NORTHWARD ACROSS MEXICO WILL
RESULT IN THE UPPER LEVEL HIGH SHIFTING EAST. FORECAST SOUNDINGS
CONTINUE TO SHOW STRONG INVERTED-V SIGNATURES UP TO ROUGHLY 500 MB
SUGGESTING CONTINUED POTENTIAL OF MOSTLY DRY THUNDERSTORMS ACROSS
THE WEST AND NORTHWEST PORTIONS OF THE CWA. FURTHER EAST...A POCKET
OF DRY AIR AHEAD OF THE APPROACHING DISTURBANCE FROM THE SOUTH WILL
LIMIT SHOWER AND T-STORM POTENTIAL...AT LEAST THROUGH MUCH OF THE
DAY. IF THE GFS VERIFIES...SOME CHANCE WILL EXIST IN THE
EVENING...BUT AT THIS POINT...NOT AS CONFIDENT ABOUT THAT.
THOUGH THE UPPER LOW WILL TRACK OVER SE NM AND WEST TEXAS...SELY
FLOW WILL BRING BETTER MOISTURE BACK TO THE CENTRAL MOUNTAIN CHAIN
AND PERHAPS INTO THE RIO GRANDE VALLEY THURSDAY NIGHT INTO FRIDAY
MORNING. BETWEEN THE ADDED MOISTURE..PERHAPS A SLIGHT COOLING AT
MID LEVELS...AND SOME WEAK CONVERGENCE AT MID LEVELS BETWEEN THE
SELY FLOW ACROSS THE EAST AS A RESULT OF THE LOW...AND WSW FLOW AT
MID LEVELS ACROSS THE WEST FOLLOWING THE PASSAGE OF THE NW
TROUGH...CENTRAL PORTIONS OF THE STATE WILL BE THE FAVORED AREA
FOR PRECIPITATION ON FRIDAY. THOUGH AMOUNTS WILL LIKELY BE
MODEST...WITH FEW EXCEPTIONS...THERE IS A BETTER CHANCE OF
MEASURABLE RAINFALL THAN WE HAVE SEEN IN A WHILE. HOWEVER...A
CHANCE FOR DRY THUNDERSTORMS REMAINS ACROSS WESTERN AREAS...ON THE
FRINGES OF THE BETTER MOISTURE. THE OTHER GOOD NEWS IS...WITH THE
ADDED CLOUD COVER AND PRECIPITATION... TEMPERATURES WILL TREND
DOWN TO NEAR NORMAL VALUES.
MOISTURE WILL RECYCLE IN THE FORM OF SHOWERS AND THUNDERSTORMS ON
SATURDAY AS THE UPPER LEVEL LOW SLOWLY DEPARTS WEST TEXAS. THEN MORE
WEST OR SOUTHWESTERLY FLOW LOOKS TO TAKE SHAPE ON SUNDAY...AND
MOISTURE ONCE AGAIN PLUMMETS. TEMPS WILL ALSO JUMP BACK UP A FEW
DEGREES. MODELS CONTINUE TO WAVER ON A BACK DOOR COLD FRONT ON
MONDAY AND THE ASSOCIATED MOISTURE IT MAY OR MAY NOT BRING TO THE
EAST. AFTER WHICH...HOWEVER...IT APPEARS A DRIER SOUTHWESTERLY FLOW
WILL BE THE RULE THROUGH MID WEEK AS THE UPPER HIGH RE-ESTABLISHES
ITSELF OVER TEXAS.
34
&&
.FIRE WEATHER...
ELONGATED UPPER LEVEL RIDGE OVER THE AREA WILL GRADUALLY WEAKEN AND
SHIFT EASTWARD THROUGH FRIDAY. AT THE SAME TIME...A TROPICAL
DISTURBANCE CURRENTLY OVER CENTRAL MEXICO WILL SLOWLY DRIFT
NORTHWARD INITIALLY BEFORE FOLLOWING A MORE NELY TRAJECTORY BY
WEEK/S END. THIS LARGE-SCALE PATTERN SHIFT WILL BRING A TEMPORARY
END TO OUR RECORD-SETTING HEAT AS WELL AS A RATHER SIGNIFICANT
INCREASE IN THUNDERSTORM ACTIVITY EAST OF THE DIVIDE BY FRIDAY AND
FRIDAY EVENING. UNFORTUNATELY...THE THREAT OF DRY LIGHTNING WILL BE
A CONCERN FOR MANY AREAS TOMORROW BUT A TREND TOWARD WETTER STORMS
IS EXPECTED BY FRIDAY ESPECIALLY FOR AREAS NEAR THE CENTRAL MOUNTAIN
CHAIN.
THERE WILL STILL BE A PRONOUNCED WESTWARD EXTENSION OF THE RIDGE
OVER THE AREA ON THURSDAY BUT THE SUBTLE EASTWARD SHIFT OF THE
PRIMARY HIGH CENTER WILL ALLOW FOR SLIGHT COOLING ALOFT THAT COMBINED
WITH A GRADUAL MOISTENING OF THE LOWER ATMOSPHERE FROM THE
MID-LEVELS DOWN WILL RESULT IN A THREAT FOR ISOLATED DRY
THUNDERSTORMS OVER THE HIGHER TERRAIN OF THE WEST ON THURSDAY WITH A
TREND TOWARD ISOLATED MIXED WET/DRY STORMS ALONG AND IMMEDIATELY
EAST OF THE CENTRAL MOUNTAIN CHAIN. THE OTHER CONCERN ON THURSDAY
WILL BE INCREASING SOUTH-SOUTHWEST WINDS ACROSS THE NORTHEAST
QUARTER. DEW POINTS WILL BE ON THE INCREASE HERE BUT WITH A
SLIGHTLY DOWNSLOPE COMPONENT HAVE TRENDED DRIER THAN THE GFS BUT
SLIGHTLY ABOVE THE NAM THAT IS BY FAR THE DRIEST. THE END RESULT
COULD BE SEVERAL HOURS OF CRITICAL FIRE WEATHER CONDITIONS ACROSS
THE NORTHEAST PLAINS. DO HAVE SOME CONCERN FOR A COUPLE HOURS OF RED
FLAG CONDITIONS ACROSS EASTERN PORTIONS OF ZONE 103-- ALONG AND EAST
OF THE INTERSTATE 25 CORRIDOR. LEFT THIS AREA OUT OF THE RED FLAG
WARNING GIVEN LIMITED IMPACT.
HUMIDITY RECOVERY TONIGHT WILL NOT BE NEAR AS BRUTAL AS THE PAST TWO
NIGHTS BUT STILL FAIR TO POOR FOR WESTERN AREAS AND THE HIGHEST
TERRAIN OF THE NORTH. MIN RH VALUES ON THURSDAY WILL BE TRENDING
UPWARD WITH SINGLE DIGIT READINGS CONFINED TO LOWER ELEVATIONS WEST
OF THE DIVIDE.
THE ABOVE MENTIONED TROPICAL LOW SHOULD BE PASSING OVER OR VERY
NEAR SOUTHEAST NEW MEXICO FRIDAY NIGHT....THOUGH MODELS DIFFER
WHEN IT MAKES ITS TURN TO THE NORTHEAST. TRENDED DEW POINTS UPWARD
CENTRAL AND ESPECIALLY EASTERN AREAS AND COULD SEE DECENT WETTING
RAIN POTENTIAL AT NIGHT ACROSS PARTS OF THE EC/SE PLAINS NEARER
THE LOW/S CORE. OTHERWISE...FRIDAY EVENING LOOKS TO BE AMONG THE
MORE ACTIVE PERIODS OF THUNDERSTORM ACTIVITY THIS FORECAST CYCLE.
THE UPPER HIGH WILL RESTRENGTHEN OVER THE AREA AS THE WEEKEND
PROGRESSES WITH DRIER AIR BECOMING PREDOMINATE. THIS SHOULD ALLOW
WARMER THAN AVERAGE DAYTIME TEMPERATURES TO RETURN ALONG WITH LOWER
HUMIDITIES ESPECIALLY CENTRAL AND WEST.
KJ
&&
.AVIATION...
18Z TAF CYCLE
VFR CONDITIONS WILL PREDOMINATE THROUGH AT LEAST 12Z THU. MODERATE
SFC WINDS WILL OCCASIONALLY GUST TO 20-25 KTS BUT SPEEDS WILL BE
LESS THAN YESTERDAY. HIGHEST CONFIDENCE IN SURFACE SMOKE IMPACTS
TO KSAF LATER TONIGHT WITH SMOKE LAYERS ALOFT JUST ABOUT ANYWHERE
WITH TRANSPORT WINDS GENERALLY FROM SW TO NE. ISOLATED HIGH BASED
-SHRA AND -TSRA ACROSS MAINLY THE CENTRAL MT CHAIN AND THE ADJACENT
HIGHLANDS IMMEDIATELY TO THE EAST BETWEEN ROUGHLY 20Z AND 04Z.
LOCALIZED GUSTY WINDS THE MAIN CONCERN WITH THIS ACTIVITY. KJ
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 57 97 59 93 / 0 0 5 5
DULCE........................... 42 89 41 87 / 0 10 10 10
CUBA............................ 53 90 50 88 / 5 20 10 10
GALLUP.......................... 49 92 50 89 / 0 5 10 5
EL MORRO........................ 47 86 44 84 / 0 20 10 10
GRANTS.......................... 48 92 51 89 / 0 20 10 10
QUEMADO......................... 56 89 55 86 / 5 10 10 10
GLENWOOD........................ 53 96 50 93 / 0 0 10 10
CHAMA........................... 44 84 46 82 / 5 20 20 10
LOS ALAMOS...................... 66 88 65 83 / 5 10 10 20
PECOS........................... 64 85 60 81 / 10 10 20 20
CERRO/QUESTA.................... 55 83 54 80 / 5 10 10 20
RED RIVER....................... 50 77 46 74 / 10 20 20 30
ANGEL FIRE...................... 37 80 38 77 / 10 10 10 30
TAOS............................ 49 88 51 87 / 5 10 10 20
MORA............................ 58 83 55 78 / 10 10 10 20
ESPANOLA........................ 60 92 59 89 / 5 5 10 10
SANTA FE........................ 63 90 59 84 / 5 5 10 20
SANTA FE AIRPORT................ 61 94 60 89 / 5 5 10 10
ALBUQUERQUE FOOTHILLS........... 68 95 68 90 / 5 5 10 10
ALBUQUERQUE HEIGHTS............. 69 97 69 92 / 5 5 10 10
ALBUQUERQUE VALLEY.............. 66 98 67 93 / 5 5 10 20
ALBUQUERQUE WEST MESA........... 65 98 66 93 / 5 5 10 10
LOS LUNAS....................... 64 98 65 94 / 0 5 10 20
RIO RANCHO...................... 64 98 66 94 / 5 5 10 10
SOCORRO......................... 66 101 65 96 / 0 5 10 20
SANDIA PARK/CEDAR CREST......... 60 93 59 88 / 5 10 20 20
TIJERAS......................... 64 94 62 90 / 5 5 10 20
MORIARTY/ESTANCIA............... 57 90 57 85 / 10 5 10 30
CLINES CORNERS.................. 60 90 58 85 / 10 5 10 30
GRAN QUIVIRA.................... 64 91 61 86 / 10 10 20 30
CARRIZOZO....................... 62 93 60 88 / 5 5 10 20
RUIDOSO......................... 59 83 56 77 / 10 10 20 40
CAPULIN......................... 57 91 58 83 / 10 5 5 20
RATON........................... 57 91 56 88 / 10 5 10 20
SPRINGER........................ 56 91 56 87 / 10 5 10 20
LAS VEGAS....................... 57 88 56 83 / 10 5 10 20
CLAYTON......................... 68 97 67 92 / 5 0 5 5
ROY............................. 63 91 62 86 / 5 5 10 10
CONCHAS......................... 69 94 67 90 / 0 0 5 5
SANTA ROSA...................... 66 93 66 88 / 0 0 10 10
TUCUMCARI....................... 70 100 70 95 / 0 0 5 5
CLOVIS.......................... 65 93 64 88 / 0 0 5 10
PORTALES........................ 66 94 66 88 / 0 0 5 20
FORT SUMNER..................... 68 94 67 89 / 0 0 5 10
ROSWELL......................... 68 95 68 90 / 0 0 10 20
PICACHO......................... 62 89 61 84 / 5 5 10 20
ELK............................. 60 84 58 79 / 5 5 20 30
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 2 PM TO 8 PM MDT THURSDAY FOR THE FOLLOWING
ZONES...NMZ104.
&&
$$
34
AREA FORECAST DISCUSSION
NWS BUFFALO NY
611 PM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK ACROSS PENNSYLVANIA LATE TONIGHT AND
THURSDAY. THIS WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO
THE SOUTHERN TIER LATE TONIGHT AND THURSDAY...WITH MORE SCATTERED SHOWERS
ELSEWHERE ON THURSDAY. AFTER THIS...HIGH PRESSURE WILL BUILD ACROSS
THE REGION LATE FRIDAY...BRINGING A RETURN TO FAIR WEATHER SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
OUR MAIN FOCUS WILL BE THE EXPECTED DEVELOPMENT OF A SIGNIFICANT
CONVECTIVE COMPLEX ACROSS THE MID-WESTERN STATES THIS EVENING. A
CONSENSUS OF THE 12 AND 18Z MODEL GUIDANCE HAS TRENDED SOUTH WITH
THE TRACK OF THIS FEATURE...WHICH IS CONSISTENT WITH OUR FORECAST
EXPECTATION THAT THE MCS IS LIKELY VEER TO THE RIGHT (SOUTHWARD)
TOWARD THE MORE UNSTABLE AIR. BECAUSE OF THIS...HAVE BEEN ABLE TO
TIGHTEN THE POP GRADIENT...RESULTING IN A DRIER FORECAST
BUFFALO-ROCHESTER NORTHWARD...WHILE CONFIDENCE REMAINS HIGH NEAR THE
NY/PA LINE. OUR REGION WILL BE ON THE NORTHERN FRINGE OF THE
COMPLEX...A SECTOR WHICH IS LESS LIKELY TO HAVE ANY SEVERE WEATHER
ASSOCIATED WITH IT. THE RGEM CONTINUES TO BE A NORTHWARD OUTLIER
AMONG MODEL GUIDANCE...SUGGESTING THERE IS A SMALL BUT DIMINISHING
CHANCE OF A MORE NORTHWARD TRACK WHICH WOULD BRING HEAVIER RAINS
INTO WESTERN NEW YORK.
GIVEN GENERAL SUPPORT FROM THE NAM/GFS/SREF...FEEL THE HRRR IS ON
THE RIGHT TRACK AND WILL BE ABLE TO MOST EFFECTIVELY CAPTURE THE
TRACK OF THE MCS TONIGHT...AND SHOULD HAVE GOOD SKILL ADVECTING THE
COMPLEX ONCE IT FULLY DEVELOPS. THERE MAY BE AN INITIAL ROUND OF
THUNDERSTORMS AHEAD OF THIS LATE EVENING...WHICH WOULD TRACK ACROSS
WESTERN PENNSYLVANIA AND FAR SOUTHERN NEW YORK. THE MAIN COMPLEX IS
FORECAST TO REACH THE OH/PA LINE AROUND 400 AM. THE CORE OF THIS
SHOULD PASS TO OUR SOUTH IT WILL LIKELY CLIP SOUTHERN PORTIONS OF
THE CWA DURING THE EARLY MORNING HOURS THROUGH MID-MORNING.
ASSOCIATED RAIN WILL LIKELY BE BUFFALO-ROCHESTER SOUTHWARD. ALONG
THE NY/PA BORDER...EXPECT PERIOD OF MODERATE TO HEAVY RAIN...WITH
SOME EMBEDDED THUNDERSTORMS POSSIBLE.
ON THURSDAY...EXPECT THE COMPLEX TO MAINTAIN STRENGTH AS IT
CONTINUES TO MOVE ACROSS PENNSYLVANIA. A SECONDARY UPPER LEVEL
SHORTWAVE WILL CATCH UP TO THE FEATURE DURING THE DAY...AND THIS
WILL LIKELY ALLOW ASSOCIATED PRECIPITATION TO SPREAD FURTHER TO THE
NORTH. BY THIS TIME...THE COMPLEX AND ASSOCIATED LOW WILL LIKELY BE
ACROSS EASTERN PENNSYLVANIA...WITH ONLY A MODEST NORTHWARD SPREAD OF
SHOWERS IN EASTERN PORTIONS OF OUR CWA. THIS SHORTWAVE MAY GENERATE
SOME LIGHT SHOWERS ON ITS OWN DURING THE LATE AFTERNOON.
FLOOD POTENTIAL IS COMPLETELY DEPENDENT ON THE TRACK OF THE
CONVECTIVE COMPLEX. GIVEN THE EXPECTED TRACK...THE HEAVIEST RAIN
WOULD REMAIN SOUTH OF OUR FORECAST AREA. RAINFALL AMOUNTS OF AROUND
AN INCH ARE EXPECTED NEAR THE NY/PA BORDER...WITH THESE LIKELY TO
DROP OFF RAPIDLY NORTHWARD. THERE STILL IS A SLIGHT CHANCE THE HEAVY
RAINS WILL MAKE IT INTO NEW YORK IF SOME OF THE OUTLIER MODEL
GUIDANCE VERIFIES. OBSERVATIONAL TRENDS SHOULD HELP FINE-TUNE THE
FORECAST DURING THE EVENING HOURS. ONE OTHER THING TO NOTE IS THAT
SOME OF OUR BASINS DO EXTEND INTO FAR NORTHERN PENNSYLVANIA. MMEFS
ENSEMBLES SHOW LOW CHANCES FOR FLOODING ON THE ALLEGHENY AT OLEAN
AND THE GENESEE AT WELLSVILLE...MAINLY DUE TO UPSTREAM RAINS. AT
THIS TIME...CONFIDENCE IS WELL BELOW WATCH THRESHOLD...BUT WILL
CONTINUE TO MENTION THIS POTENTIAL IN THE HWO.
TEMPERATURES WILL DROP ONLY MODESTLY OVERNIGHT IN MOST
LOCATIONS...WITH LOWS MAINLY IN THE UPPER 50S TO LOWER 60S. IT WILL
BE A BIT COOLER EAST OF LAKE ONTARIO WHERE CLOUDS WILL NOT MOVE IN
UNTIL LATER. ON THURSDAY...HIGHS SHOULD RANGE FROM THE UPPER 60S TO
AROUND 70.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
BY THURSDAY EVENING THE STRONG MID LEVEL CIRCULATION AND ASSOCIATED
SURFACE LOW WILL BE REACHING THE DELMARVA PENINSULA...CARRYING ANY
SHOWERS WELL SOUTH AND EAST OF THE AREA. OUR ATTENTION THEN TURNS TO
ANOTHER MUCH WEAKER NORTHERN STREAM SHORTWAVE...WHICH WILL BE
DIGGING ACROSS THE LOWER LAKES IN THE EVENING AND WILL EVENTUALLY
PHASE WITH THE FIRST SYSTEM OVERNIGHT. THE DEEPER MOISTURE
ASSOCIATED WITH THIS SECOND FEATURE WILL BE BEHIND THE MID LEVEL
SHORTWAVE AND CLOSER TO A WEAK LOW LEVEL TROUGH. THIS MAY TOUCH OFF
A FEW MORE SHOWERS OVERNIGHT INTO FRIDAY MORNING AS IT CROSSES THE
REGION...BUT THEY SHOULD BE WIDELY SCATTERED AND LIGHT IN NATURE.
BY FRIDAY AFTERNOON DEEPER MOISTURE AND LIFT WITH THIS SECOND WAVE
WILL MOVE SOUTHEAST OF THE AREA...WITH A MUCH DRIER AIRMASS
ADVECTING INTO THE LOWER LAKES DURING THE AFTERNOON. ANY LEFTOVER
SCATTERED SHOWERS THROUGH MIDDAY WILL END FROM NORTHWEST TO
SOUTHEAST DURING THE AFTERNOON WITH CLEARING SKIES LATE IN THE DAY.
FRIDAY NIGHT INTO SATURDAY HIGH PRESSURE WILL BUILD INTO THE GREAT
LAKES AND OHIO VALLEY. THIS WILL BRING A RETURN TO DRY AND CLEAR
WEATHER...AND ALSO DELIVER A COOLER/DRIER AIRMASS INTO THE REGION.
LOWS WILL BE ON THE COOL SIDE FRIDAY NIGHT WITH LOWER 50S ON THE
LAKE PLAINS AND 40S IN THE INTERIOR SOUTHERN TIER AND EAST OF LAKE
ONTARIO. AFTER A COOL START...SATURDAY WILL WARM NICELY UNDER FULL
SUNSHINE WITH 850MB TEMPS AROUND +9C. THIS SHOULD SUPPORT HIGHS IN
THE LOWER TO MID 70S AT LOWER ELEVATIONS. THE WEAK SYNOPTIC SCALE
PRESSURE GRADIENT AND STRONG DIFFERENTIAL HEATING WILL SUPPORT LAKE
BREEZE DEVELOPMENT WITH COOLER TEMPS ALONG THE LAKESHORES.
SATURDAY NIGHT HIGH PRESSURE WILL BEGIN TO DRIFT TO THE EASTERN
SEABOARD...WITH SOUTHWEST RETURN FLOW BEGINNING. THIS WILL HELP KEEP
LOWS A LITTLE MORE MILD THAN FRIDAY NIGHT ESPECIALLY ACROSS WESTERN
NY. INCREASING WARM ADVECTION AND ISENTROPIC UPGLIDE WILL BRING SOME
INCREASE IN CLOUDS FROM WEST TO EAST OVERNIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
BY SUNDAY THE RIDGE ACROSS THE CENTRAL CONUS WILL BEGIN TO BREAK
DOWN AS FLOW BECOMES ZONAL AGAIN OVER THE NORTHERN TIER OF THE
NATION. THIS WILL ALLOW A SERIES OF WEAK AND FAST MOVING SHORTWAVES
TO MOVE THROUGH THE GREAT LAKES REGION. THE 12Z GFS AND ECMWF HAVE
COME INTO A LITTLE BETTER AGREEMENT TODAY WITH RESPECT TO SUNDAY...
AS BOTH MOVE THE FIRST SHORTWAVE INTO THE LOWER LAKES DURING THE
DAY. THIS MAY TOUCH OF A FEW SCATTERED SHOWERS AND THUNDERSTORMS
DURING THE AFTERNOON...ALTHOUGH IT LOOKS LIKE COVERAGE WILL REMAIN
SPARSE. THE NEXT IN A SERIES OF SHORTWAVES WILL CROSS THE AREA
MONDAY OR MONDAY NIGHT WITH A CHANCE OF A FEW MORE SHOWERS AND
STORMS...ALTHOUGH TIMING OF INDIVIDUAL WAVES IS UNCERTAIN AT THIS
TIME RANGE.
BY TUESDAY AND WEDNESDAY MODEL UNCERTAINTY BEGINS TO INCREASE AS THE
ECMWF HANGS ONTO MORE OF A TROUGH AND DEEPER MOISTURE ACROSS THE
GREAT LAKES. THIS WOULD ALLOW AT LEAST A LOW CHANCE OF SHOWERS AND A
FEW THUNDERSTORMS TO LINGER TUESDAY AND WEDNESDAY. THE GFS ON THE
OTHER HAND PUSHES THE TROUGH A LITTLE FARTHER EAST...WITH HIGH
PRESSURE BUILDING INTO THE GREAT LAKES LATER TUESDAY AFTERNOON AND
WEDNESDAY. FOR NOW WILL STICK CLOSE TO PREVIOUS FORECAST CONTINUITY
WITH A LOW CHANCE ON TUESDAY THEN DRY ON WEDNESDAY UNTIL BETTER
MODEL AGREEMENT IS REACHED.
TEMPERATURES WILL WARM TO A LITTLE ABOVE AVERAGE BY SUNDAY AND
MONDAY AS A WARMER AIRMASS MOVES INTO THE AREA FROM THE MIDWEST. IF
THE MORE PROGRESSIVE GFS VERIFIES...TEMPERATURES WOULD COOL BACK TO
AVERAGE AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES.
&&
.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS WILL CONTINUE AREA-WIDE THROUGH THIS EVENING AS WEAK
HIGH PRESSURE BUILDS ACROSS NEW YORK STATE.
AFTER THIS...THE FORECAST WILL DEPEND ON THE EVOLUTION OF A STRONG
CONVECTIVE COMPLEX WHICH IS FORECAST TO DEVELOP ACROSS THE MID-
WEST AND TRACK ESE ACROSS PENNSYLVANIA. AS THE COMPLEX STRENGTHENS
OVERNIGHT...IT WILL LIKELY CURVE TO THE RIGHT PUSHING IT SOUTHWARD
WHERE THE MORE UNSTABLE AIR LIES. GIVEN THIS LIKELIHOOD...EXPECT
ONLY A MINIMAL IMPACT ON ALL OF OUR TAF SITES WITH THE EXCEPTION OF
JHW...WHICH WILL LIKELY CATCH THE NORTHERN FRINGE OF THE ASSOCIATED
PRECIPITATION SHIELD. THIS SAID...THERE IS A SLIGHT CHANCE THIS
COMPLEX WILL TRACK NORTH OF THIS FORECAST...AND IF IT DOES IT WOULD
HAVE A SIGNIFICANT IMPACT ON THE BUF/IAG/ROC TERMINALS.
ON THURSDAY...THE CONVECTIVE COMPLEX AND ASSOCIATED LOW PRESSURE
WILL EXIT EAST...WITH A DEVELOPING NE FLOW. THIS WILL LIKELY LOWER
CIGS...BUT PROBABLY STILL JUST ABOVE 3000 FT IN THE VFR CATEGORY.
OUTLOOK...
THURSDAY NIGHT AND FRIDAY...MVFR/VFR WITH A CHANCE OF SHOWERS.
SATURDAY AND SUNDAY...MAINLY VFR.
&&
.MARINE...
LOW PRESSURE WILL PASS JUST TO THE SOUTH OF THE LOWER LAKES TONIGHT
AND THURSDAY...WITH WINDS INITIALLY INCREASING OUT OF THE
EAST...THEN BACKING TO NORTH DURING THURSDAY. AT THIS POINT...IT
STILL APPEARS THAT WINDS AND WAVES MAY INCREASE JUST ENOUGH TO
EVENTUALLY WARRANT SMALL CRAFT ADVISORIES FOR WESTERN LAKE ONTARIO
AND LAKE ERIE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL/RSH
SHORT TERM...HITCHCOCK
LONG TERM...AR/HITCHCOCK
AVIATION...APFFEL/RSH
MARINE...APFFEL/HITCHCOCK
AREA FORECAST DISCUSSION
NWS BUFFALO NY
348 PM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK ACROSS PENNSYLVANIA LATE TONIGHT AND
THURSDAY. THIS WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO
THE SOUTHERN TIER LATE TONIGHT AND THURSDAY...WITH MORE SCATTERED SHOWERS
ELSEWHERE ON THURSDAY. AFTER THIS...HIGH PRESSURE WILL BUILD ACROSS
THE REGION LATE FRIDAY...BRINGING A RETURN TO FAIR WEATHER SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
OUR MAIN FOCUS WILL BE THE EXPECTED DEVELOPMENT OF A SIGNIFICANT
CONVECTIVE COMPLEX ACROSS THE MID-WESTERN STATES LATE THIS
AFTERNOON. A CONSENSUS OF THE 12Z MODEL GUIDANCE HAS TRENDED
SOUTH WITH THE TRACK OF THIS...WHICH IS CONSISTENT WITH OUR FORECAST
EXPECTATION THAT THE MCS IS LIKELY VEER TO THE RIGHT (SOUTHWARD)
TOWARD THE MORE UNSTABLE AIR. BECAUSE OF THIS...HAVE BEEN ABLE TO
TIGHTEN THE POP GRADIENT...RESULTING IN A DRIER FORECAST
BUFFALO-ROCHESTER NORTHWARD...WHILE CONFIDENCE REMAINS HIGH NEAR THE
NY/PA LINE. OUR REGION WILL BE ON THE NORTHERN FRINGE OF THE
COMPLEX...A SECTOR WHICH IS LESS LIKELY TO HAVE ANY SEVERE WEATHER
ASSOCIATED WITH IT. THE RGEM CONTINUES TO BE A NORTHWARD OUTLIER
AMONG MODEL GUIDANCE...SUGGESTING THERE IS A SMALL BUT DIMINISHING
CHANCE OF A MORE NORTHWARD TRACK WHICH WOULD BRING HEAVIER RAINS
INTO WESTERN NEW YORK.
FOR THE REMAINDER OF THIS AFTERNOON...IT SHOULD CONTINUE TO BE
QUITE PLEASANT...WITH PARTLY TO MOSTLY SUNNY SKIES ACROSS WESTERN
NEW YORK AND TEMPERATURES MAINLY IN THE 70S. RADAR SHOWS A FEW LIGHT
SHOWERS STREAMING ACROSS NE OHIO AND EASTERN MICHIGAN...WITH THIS
ARE LIKELY TO LIFT TO AROUND CHAUTAUQUA COUNTY BEFORE FALLING APART
AROUND SUNSET.
GIVEN GENERAL SUPPORT FROM THE NAM/GFS/SREF...FEEL THE HRRR IS ON
THE RIGHT TRACK AND WILL BE ABLE TO MOST EFFECTIVELY CAPTURE THE
TRACK OF THE MCS...AND SHOULD HAVE GOOD SKILL ADVECTING THE
COMPLEX ONCE IT FULLY DEVELOPS. THERE MAY BE AN INITIAL ROUND OF
THUNDERSTORMS AHEAD OF THIS LATE EVENING...WHICH WOULD TRACK ACROSS
WESTERN PENNSYLVANIA AND FAR SOUTHERN NEW YORK LATE THIS EVENING.
THE MAIN COMPLEX IS FORECAST TO REACH THE OH/PA LINE AROUND 400 AM.
THE CORE OF THIS SHOULD PASS TO OUR SOUTH IT WILL LIKELY CLIP
SOUTHERN PORTIONS OF THE CWA DURING THE EARLY MORNING HOURS THROUGH
MID-MORNING. ASSOCIATED RAIN WILL LIKELY BE BUFFALO-ROCHESTER
SOUTHWARD. ALONG THE NY/PA BORDER...EXPECT PERIOD OF MODERATE TO
HEAVY RAIN...WITH SOME EMBEDDED THUNDERSTORMS POSSIBLE.
ON THURSDAY...EXPECT THE COMPLEX TO MAINTAIN STRENGTH AS IT
CONTINUES TO MOVE ACROSS PENNSYLVANIA. A SECONDARY UPPER LEVEL
SHORTWAVE WILL CATCH UP TO THE FEATURE DURING THE DAY...AND THIS
WILL LIKELY ALLOW ASSOCIATED PRECIPITATION TO SPREAD FURTHER TO THE
NORTH. BY THIS TIME...THE COMPLEX AND ASSOCIATED LOW WILL LIKELY BE
ACROSS EASTERN PENNSYLVANIA...WITH ONLY A MODEST NORTHWARD SPREAD OF
SHOWERS IN EASTERN PORTIONS OF OUR CWA. THIS SHORTWAVE MAY GENERATE
SOME LIGHT SHOWERS ON ITS OWN DURING THE LATE AFTERNOON.
FLOOD POTENTIAL IS COMPLETELY DEPENDENT ON THE TRACK OF THE
CONVECTIVE COMPLEX. GIVEN THE EXPECTED TRACK...THE HEAVIEST RAIN
WOULD REMAIN SOUTH OF OUR FORECAST AREA. RAINFALL AMOUNTS OF AROUND
AN INCH ARE EXPECTED NEAR THE NY/PA BORDER...WITH THESE LIKELY TO
DROP OFF RAPIDLY NORTHWARD. THERE STILL IS A SLIGHT CHANCE THE HEAVY
RAINS WILL MAKE IT INTO NEW YORK IF SOME OF THE OUTLIER MODEL
GUIDANCE VERIFIES. OBSERVATIONAL TRENDS SHOULD HELP FINE-TUNE THE
FORECAST DURING THE EVENING HOURS. ONE OTHER THING TO NOTE IS THAT
SOME OF OUR BASINS DO EXTEND INTO FAR NORTHERN PENNSYLVANIA. MMEFS
ENSEMBLES SHOW LOW CHANCES FOR FLOODING ON THE ALLEGHENY AT OLEAN
AND THE GENESEE AT WELLSVILLE...MAINLY DUE TO UPSTREAM RAINS. AT
THIS TIME...CONFIDENCE IS WELL BELOW WATCH THRESHOLD...BUT WILL
CONTINUE TO MENTION THIS POTENTIAL IN THE HWO.
TEMPERATURES WILL DROP ONLY MODESTLY OVERNIGHT IN MOST
LOCATIONS...WITH LOWS MAINLY IN THE UPPER 50S TO LOWER 60S. IT WILL
BE A BIT COOLER EAST OF LAKE ONTARIO WHERE CLOUDS WILL NOT MOVE IN
UNTIL LATER. ON THURSDAY...HIGHS SHOULD RANGE FROM THE UPPER 60S TO
AROUND 70.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
BY THURSDAY EVENING THE STRONG MID LEVEL CIRCULATION AND ASSOCIATED
SURFACE LOW WILL BE REACHING THE DELMARVA PENINSULA...CARRYING ANY
SHOWERS WELL SOUTH AND EAST OF THE AREA. OUR ATTENTION THEN TURNS TO
ANOTHER MUCH WEAKER NORTHERN STREAM SHORTWAVE...WHICH WILL BE
DIGGING ACROSS THE LOWER LAKES IN THE EVENING AND WILL EVENTUALLY
PHASE WITH THE FIRST SYSTEM OVERNIGHT. THE DEEPER MOISTURE
ASSOCIATED WITH THIS SECOND FEATURE WILL BE BEHIND THE MID LEVEL
SHORTWAVE AND CLOSER TO A WEAK LOW LEVEL TROUGH. THIS MAY TOUCH OFF
A FEW MORE SHOWERS OVERNIGHT INTO FRIDAY MORNING AS IT CROSSES THE
REGION...BUT THEY SHOULD BE WIDELY SCATTERED AND LIGHT IN NATURE.
BY FRIDAY AFTERNOON DEEPER MOISTURE AND LIFT WITH THIS SECOND WAVE
WILL MOVE SOUTHEAST OF THE AREA...WITH A MUCH DRIER AIRMASS
ADVECTING INTO THE LOWER LAKES DURING THE AFTERNOON. ANY LEFTOVER
SCATTERED SHOWERS THROUGH MIDDAY WILL END FROM NORTHWEST TO
SOUTHEAST DURING THE AFTERNOON WITH CLEARING SKIES LATE IN THE DAY.
FRIDAY NIGHT INTO SATURDAY HIGH PRESSURE WILL BUILD INTO THE GREAT
LAKES AND OHIO VALLEY. THIS WILL BRING A RETURN TO DRY AND CLEAR
WEATHER...AND ALSO DELIVER A COOLER/DRIER AIRMASS INTO THE REGION.
LOWS WILL BE ON THE COOL SIDE FRIDAY NIGHT WITH LOWER 50S ON THE
LAKE PLAINS AND 40S IN THE INTERIOR SOUTHERN TIER AND EAST OF LAKE
ONTARIO. AFTER A COOL START...SATURDAY WILL WARM NICELY UNDER FULL
SUNSHINE WITH 850MB TEMPS AROUND +9C. THIS SHOULD SUPPORT HIGHS IN
THE LOWER TO MID 70S AT LOWER ELEVATIONS. THE WEAK SYNOPTIC SCALE
PRESSURE GRADIENT AND STRONG DIFFERENTIAL HEATING WILL SUPPORT LAKE
BREEZE DEVELOPMENT WITH COOLER TEMPS ALONG THE LAKESHORES.
SATURDAY NIGHT HIGH PRESSURE WILL BEGIN TO DRIFT TO THE EASTERN
SEABOARD...WITH SOUTHWEST RETURN FLOW BEGINNING. THIS WILL HELP KEEP
LOWS A LITTLE MORE MILD THAN FRIDAY NIGHT ESPECIALLY ACROSS WESTERN
NY. INCREASING WARM ADVECTION AND ISENTROPIC UPGLIDE WILL BRING SOME
INCREASE IN CLOUDS FROM WEST TO EAST OVERNIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
BY SUNDAY THE RIDGE ACROSS THE CENTRAL CONUS WILL BEGIN TO BREAK
DOWN AS FLOW BECOMES ZONAL AGAIN OVER THE NORTHERN TIER OF THE
NATION. THIS WILL ALLOW A SERIES OF WEAK AND FAST MOVING SHORTWAVES
TO MOVE THROUGH THE GREAT LAKES REGION. THE 12Z GFS AND ECMWF HAVE
COME INTO A LITTLE BETTER AGREEMENT TODAY WITH RESPECT TO SUNDAY...
AS BOTH MOVE THE FIRST SHORTWAVE INTO THE LOWER LAKES DURING THE
DAY. THIS MAY TOUCH OF A FEW SCATTERED SHOWERS AND THUNDERSTORMS
DURING THE AFTERNOON...ALTHOUGH IT LOOKS LIKE COVERAGE WILL REMAIN
SPARSE. THE NEXT IN A SERIES OF SHORTWAVES WILL CROSS THE AREA
MONDAY OR MONDAY NIGHT WITH A CHANCE OF A FEW MORE SHOWERS AND
STORMS...ALTHOUGH TIMING OF INDIVIDUAL WAVES IS UNCERTAIN AT THIS
TIME RANGE.
BY TUESDAY AND WEDNESDAY MODEL UNCERTAINTY BEGINS TO INCREASE AS THE
ECMWF HANGS ONTO MORE OF A TROUGH AND DEEPER MOISTURE ACROSS THE
GREAT LAKES. THIS WOULD ALLOW AT LEAST A LOW CHANCE OF SHOWERS AND A
FEW THUNDERSTORMS TO LINGER TUESDAY AND WEDNESDAY. THE GFS ON THE
OTHER HAND PUSHES THE TROUGH A LITTLE FARTHER EAST...WITH HIGH
PRESSURE BUILDING INTO THE GREAT LAKES LATER TUESDAY AFTERNOON AND
WEDNESDAY. FOR NOW WILL STICK CLOSE TO PREVIOUS FORECAST CONTINUITY
WITH A LOW CHANCE ON TUESDAY THEN DRY ON WEDNESDAY UNTIL BETTER
MODEL AGREEMENT IS REACHED.
TEMPERATURES WILL WARM TO A LITTLE ABOVE AVERAGE BY SUNDAY AND
MONDAY AS A WARMER AIRMASS MOVES INTO THE AREA FROM THE MIDWEST. IF
THE MORE PROGRESSIVE GFS VERIFIES...TEMPERATURES WOULD COOL BACK TO
AVERAGE AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS WILL CONTINUE AREA-WIDE THROUGH THIS EVENING AS WEAK
HIGH PRESSURE BUILDS ACROSS NEW YORK STATE.
AFTER THIS...THE FORECAST WILL DEPEND ON THE EVOLUTION OF A STRONG
CONVECTIVE COMPLEX WHICH IS FORECAST TO DEVELOP ACROSS THE MID-
WEST AND TRACK ESE ACROSS PENNSYLVANIA. AS THE COMPLEX STRENGTHENS
LATE THIS EVENING...IT WILL LIKELY CURVE TO THE RIGHT PUSHING IT
SOUTHWARD WHERE THE MORE UNSTABLE AIR LIES. GIVEN THIS
LIKELIHOOD...EXPECT ONLY A MINIMAL IMPACT ON ALL OF OUR TAF SITES
WITH THE EXCEPTION OF JHW...WHICH WILL LIKELY CATCH THE NORTHERN
FRINGE OF THE ASSOCIATED PRECIPITATION SHIELD. THIS SAID...THERE
IS A SLIGHT CHANCE THIS COMPLEX WILL TRACK NORTH OF THIS
FORECAST...AND IF IT DOES IT WOULD HAVE A SIGNIFICANT IMPACT ON
THE BUF/IAG/ROC TERMINALS.
ON THURSDAY...THE CONVECTIVE COMPLEX AND ASSOCIATED LOW PRESSURE
WILL EXIT EAST...WITH A DEVELOPING NE FLOW. THIS WILL LIKELY LOWER
CIGS...BUT PROBABLY STILL JUST ABOVE 3000 FT IN THE VFR CATEGORY.
OUTLOOK...
THURSDAY NIGHT AND FRIDAY...MVFR/VFR WITH A CHANCE OF SHOWERS.
SATURDAY AND SUNDAY...MAINLY VFR.
&&
.MARINE...
LOW PRESSURE WILL PASS JUST TO THE SOUTH OF THE LOWER LAKES TONIGHT
AND THURSDAY...WITH WINDS INITIALLY INCREASING OUT OF THE
EAST...THEN BACKING TO NORTH DURING THURSDAY. AT THIS POINT...IT
STILL APPEARS THAT WINDS AND WAVES MAY INCREASE JUST ENOUGH TO
EVENTUALLY WARRANT SMALL CRAFT ADVISORIES FOR WESTERN LAKE ONTARIO
AND LAKE ERIE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...HITCHCOCK
LONG TERM...AR/HITCHCOCK
AVIATION...APFFEL
MARINE...APFFEL/HITCHCOCK
AREA FORECAST DISCUSSION
NWS BUFFALO NY
210 PM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK ACROSS PENNSYLVANIA TONIGHT AND
THURSDAY. THIS WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO
THE SOUTHERN TIER LATE TONIGHT...AND POSSIBLY A SHOWERS ELSEWHERE
ON THURSDAY. AFTER THIS...HIGH PRESSURE WILL BUILD ACROSS THE
REGION...BRINGING A RETURN TO FAIR WEATHER LATE FRIDAY AND
SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
OUR MAIN FORECAST FOCUS WILL BE THE EXPECTED DEVELOPMENT OF A
SIGNIFICANT CONVECTIVE COMPLEX ACROSS THE MID-WESTERN STATES LATER
TODAY. 12Z GUIDANCE HAS ALL TRENDED SOUTHWARD WITH THE TRACK OF
THIS...WHICH IS CONSISTENT WITH OUR FORECAST PHILOSOPHY THAT THE
MCS WILL LIKELY VEER TO THE RIGHT (SOUTHWARD) TOWARD THE MORE
UNSTABLE AIR. BECAUSE OF THIS...HAVE BEEN ABLE TO TIGHTEN THE POP
GRADIENT...RESULTING IN A DRIER FORECAST BUFFALO-ROCHESTER
NORTHWARD...WHILE CONFIDENCE REMAINS HIGH IN A PERIOD OF RAIN
SHOWERS NEAR THE NY/PA LINE. OUR REGION WILL BE ON THE NORTHERN
FRINGE OF THE COMPLEX...A SECTOR WHICH IS LESS LIKELY TO HAVE ANY
SEVERE WEATHER ASSOCIATED WITH IT. THE RGEM CONTINUES TO BE A
NORTHWARD OUTLIER AMONG MODEL GUIDANCE...SUGGESTING THERE IS A
SMALL BUT DIMINISHING CHANCE OF A MORE NORTHWARD TRACK WHICH WOULD
BRING HEAVIER RAINS INTO WESTERN NEW YORK.
FOR THE REMAINDER OF THIS AFTERNOON...IT SHOULD CONTINUE TO BE
QUITE PLEASANT...WITH PARTLY TO MOSTLY SUNNY SKIES ACROSS WESTERN
NEW YORK AND TEMPERATURES MAINLY IN THE 70S. RADAR SHOWS A FEW
LIGHT SHOWERS STREAMING ACROSS NE OHIO AND EASTERN MICHIGAN...BUT
THESE ARE LIKELY TO REMAIN JUST SOUTH OF OUR REGION.
GIVEN SUPPORT FROM THE NAM/GFS/SREF...FEEL THE HRRR WILL BE ABLE
TO MOST EFFECTIVELY CAPTURE THIS FEATURE...AND SHOULD HAVE GOOD
SKILL ADVECTING THE COMPLEX ONCE IT FULLY DEVELOPS. THERE MAY BE
AN INITIAL ROUND OF THUNDERSTORMS WHICH SHOULD TRACK ACROSS
WESTERN PENNSYLVANIA THIS EVENING. THE MAIN COMPLEX IS FORECAST
TO REACH CENTRAL LAKE ERIE SHORTLY AFTER MIDNIGHT...WITH ANY
IMPACTS TO OUR REGION LIKELY TO HOLD OFF UNTIL AFTER 3 AM. THIS
SHOULD PASS SOUTH BUT CLIP THE SOUTHERN TIER DURING THE EARLY
MORNING HOURS...THROUGH MID-MORNING. EXPECT PERIOD OF MODERATE
TO HEAVY RAIN...WITH SOME EMBEDDED THUNDERSTORMS POSSIBLE.
ON THURSDAY...EXPECT THE COMPLEX TO MAINTAIN STRENGTH AS IT MOVES
ACROSS PENNSYLVANIA. A SECONDARY UPPER LEVEL SHORTWAVE WILL CATCH
UP TO THE FEATURE DURING THE DAY...AND THIS WILL LIKELY ALLOW
ASSOCIATED PRECIPITATION TO SPREAD FURTHER TO THE NORTH. BY THIS
TIME...THE COMPLEX AND ASSOCIATED LOW WILL LIKELY BE ACROSS
EASTERN PENNSYLVANIA...WITH ONLY A MODEST NORTHWARD SPREAD OF
SHOWERS IN EASTERN PORTIONS OF OUR CWA. THIS SHORTWAVE MAY
GENERATE SOME LIGHT SHOWERS ON ITS OWN DURING THE LATE AFTERNOON.
FLOOD POTENTIAL IS COMPLETELY DEPENDENT ON THE TRACK OF THE
COMPLEX. GIVEN THE EXPECTED TRACK...THE HEAVIEST RAIN WOULD REMAIN
SOUTH OF OUR FORECAST AREA. RAINFALL AMOUNTS OF AROUND AN INCH ARE
EXPECTED NEAR THE NY/PA BORDER...WITH THESE LIKELY TO DROP OFF
RAPIDLY NORTHWARD. THERE STILL IS A SLIGHT CHANCE THE HEAVY RAINS
WILL MAKE IT INTO NEW YORK IF SOME OF THE OUTLIER MODEL GUIDANCE
VERIFIES. OBSERVATIONAL TRENDS SHOULD HELP FINE-TUNE THE FORECAST
DURING THE EVENING HOURS. ONE OTHER THING TO NOTE IS THAT SOME OF
OUR BASINS DO EXTEND INTO FAR NORTHERN PENNSYLVANIA. MMEFS
ENSEMBLES SHOW LOW CHANCES FOR FLOODING ON THE ALLEGHENY AT OLEAN
AND THE GENESEE AT WELLSVILLE...MAINLY DUE TO UPSTREAM RAINS. AT
THIS TIME...CONFIDENCE IS WELL BELOW WATCH THRESHOLD...BUT WILL
CONTINUE TO MENTION THIS POTENTIAL IN THE HWO.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
EVENTUALLY THE LOW PRESSURE SYSTEM WILL MOVE OUT AND EAST OF THE
AREA THURSDAY NIGHT. THIS WILL TAPER THE RAINS OFF FROM WEST TO EAST.
MODELS DO SLOW THE CUTOFF OVER NEW ENGLAND AS A NORTHERN STREAM
SYSTEM PHASE WITH IT WHICH MAY ALLOW SOME SCATTERED SHOWERS TO
LINGER ACROSS THE REGION EARLY FRIDAY. THIS SYSTEM LOOK TO LIFT OUT
LATER FRIDAY ALLOWING HIGH PRESSURE AND DRIER AIR TO BUILD INTO THE
REGION.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ON SATURDAY HIGH PRESSURE WILL BUILD ACROSS THE GREAT LAKES AND
FINALLY PROVIDE A RETURN TO SUNSHINE AND LOWER HUMIDITY. AFTER A
COOL START TEMPERATURES WILL REBOUND TO WITHIN A FEW DEGREES OF
AVERAGE.
BY SUNDAY MODEL GUIDANCE BEGINS TO DIVERGE ONCE AGAIN. THE GFS HAS
TRENDED FASTER WITH THE NEXT SYSTEM AS IT QUICKLY BREAKS DOWN THE
UPSTREAM RIDGE OVER THE MIDWEST. THIS WOULD BRING SHOWER AND
THUNDERSTORM CHANCES BACK INTO THE AREA AS EARLY AS SUNDAY. THE
ECMWF REMAINS A LITTLE SLOWER...WITH BETTER RAIN CHANCES HOLDING OFF
UNTIL SUNDAY NIGHT AND MONDAY. FOR NOW WILL GO WITH THE SLOWER ECMWF
SOLUTION...ALTHOUGH IF THE GFS TREND CONTINUES LATER FORECASTS MAY
NEED TO INTRODUCE RAIN CHANCES FOR SUNDAY.
BY NEXT WEEK BOTH THE GFS AND ECMWF CONTINUE THE PROGRESSIVE
NORTHWEST FLOW ALONG THE US/CANADIAN BORDER WITH NUMEROUS SHORTWAVES
TRAVERSING THE NORTHWEST FLOW. TIMING AGREEMENT COMPLETELY BREAKS
DOWN BY TUESDAY AMONGST VARIOUS MEDIUM RANGE OPERATIONAL AND
ENSEMBLE GUIDANCE. WITH THIS IN MIND WILL JUST CONTINUE WITH THE LOW
CHANCE POPS THROUGH TUESDAY UNTIL BETTER TIMING AGREEMENT CAN BE
ACHIEVED IN MODEL GUIDANCE. TEMPERATURES WILL REMAIN VERY CLOSE TO
AVERAGE THROUGH THE PERIOD.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS WILL CONTINUE AREA-WIDE THROUGH THIS EVENING AS WEAK
HIGH PRESSURE BUILDS ACROSS NEW YORK STATE.
AFTER THIS...THE FORECAST WILL DEPEND ON THE EVOLUTION OF A STRONG
CONVECTIVE COMPLEX WHICH IS FORECAST TO DEVELOP ACROSS THE MID-
WEST AND TRACK ESE ACROSS PENNSYLVANIA. AS THE COMPLEX STRENGTHENS
LATE THIS EVENING...IT WILL LIKELY CURVE TO THE RIGHT PUSHING IT
SOUTHWARD WHERE THE MORE UNSTABLE AIR LIES. GIVEN THIS
LIKELIHOOD...EXPECT ONLY A MINIMAL IMPACT ON ALL OF OUR TAF SITES
WITH THE EXCEPTION OF JHW...WHICH WILL LIKELY CATCH THE NORTHERN
FRINGE OF THE ASSOCIATED PRECIPITATION SHIELD. THIS SAID...THERE
IS A SLIGHT CHANCE THIS COMPLEX WILL TRACK NORTH OF THIS
FORECAST...AND IF IT DOES IT WOULD HAVE A SIGNIFICANT IMPACT ON
THE BUF/IAG/ROC TERMINALS.
ON THURSDAY...THE CONVECTIVE COMPLEX AND ASSOCIATED LOW PRESSURE
WILL EXIT EAST...WITH A DEVELOPING NE FLOW. THIS WILL LIKELY LOWER
CIGS...BUT PROBABLY STILL JUST ABOVE 3000 FT IN THE VFR CATEGORY.
OUTLOOK...
THURSDAY NIGHT AND FRIDAY...MVFR/VFR WITH A CHANCE OF SHOWERS.
SATURDAY AND SUNDAY...MAINLY VFR.
&&
.MARINE...
LIGHT AND VARIABLE WINDS THIS MORNING WITH THE PRESSURE GRADIENT
OVER THE LOWER LAKES WEAKENING. LAKE BREEZES SHOULD DEVELOP THIS
AFTERNOON GIVEN THE WEAK OVERALL GRADIENT.
LOOKING A LITTLE FURTHER AHEAD...ANOTHER REGION OF LOW PRESSURE WILL
PASS JUST TO THE SOUTH OF THE LOWER LAKES TONIGHT AND
THURSDAY...WITH WINDS INITIALLY INCREASING OUT OF THE EAST...THEN
BACKING TO NORTH DURING THURSDAY. AT THIS POINT...IT STILL APPEARS
THAT WINDS AND WAVES MAY INCREASE JUST ENOUGH TO EVENTUALLY WARRANT
SMALL CRAFT ADVISORIES FOR WESTERN LAKE ONTARIO AND LAKE ERIE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...TMA
LONG TERM...HITCHCOCK
AVIATION...APFFEL
MARINE...JJR/SMITH/APFFEL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
745 PM EDT THU JUN 13 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL CROSS THE MID ATLANTIC...AND THE TRAILING
COLD FRONT WILL CROSS THE REGION THROUGH TONIGHT. HIGH PRESSURE WILL
BUILD IN BEHIND THE FRONT FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 300 PM THURSDAY...
...PARTICULARLY DANGEROUS SITUATION SEVERE THUNDERSTORM WATCH IN
EFFECT...
PDS SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 10 PM. THE LATEST
SPC MESOANALYSIS PAGE SHOWED MLCAPE FROM NEARLY 2000J/KG TO CLOSE TO
4000J/KG ACROSS CENTRAL NORTH CAROLINA. 0-6KM SHEAR WAS STILL BETTER
NORTH...FROM NEAR THE VIRGINIA BORDER NORTH INTO VIRGINIA...BUT
DOWNDRAFT CAPE WAS A ROBUST 1000-1500J/KG THROUGHOUT CENTRAL NORTH
CAROLINA. MSAS SURFACE-BASED LIFTED INDICES WERE -8C TO -10C. THE
LATEST KGSO SOUNDING...FROM 18Z...SHOWED A CAP REMAINING AROUND
800MB BUT WITH THE LAYER AROUND 800MB COOLING SINCE 12Z. THE 18Z
SOUNDING AT KRNK SHOWED THE CAP JUST ABOVE 800MB HAD ERODED...
SUFFICIENTLY FOR A GUST AT KROA TO 59KT WITH STORM PASSAGE AT 1828Z.
THE LATEST HRRR WRF CONTINUES WITH A TIMING OF 19Z TO 21Z IN THE
IMMEDIATE TRIAD...21Z TO 23Z IN THE TRIANGLE NEAR KRDU AND SOUTHWEST
ALONG U.S. 1...AND IN VICINITY OF 22Z OR JUST A LITTLE LATER TOWARD
KRWI...KFAY...AND THE INTERSTATE 95 CORRIDOR. WHILE THE 0-3KM STORM
RELATIVE HELICITY ON THE 18Z KGSO SOUNDING WAS 84M2/S2...ONE STILL
CANNOT COMPLETELY RULE OUT A TORNADO...AS STORM RELATIVE HELICITY IN
THE LOWEST 3KM ON THE SPC MESOANALYSIS PAGE APPEARED PRETTY ACCURATE
AND WAS ABOVE 100M2/S2 OVER MOST OF THE REST OF CENTRAL NORTH
CAROLINA...HIGHEST RELATIVE TO THE REST OF CENTRAL NORTH CAROLINA
NORTHEAST OF THE TRIANGLE. -10C TO -30C CAPE IS ON THE ORDER OF
1000J/KG AS WELL...SUFFICIENT FOR THE POTENTIAL FOR LARGE HAIL AND
ASSISTING WITH FREQUENT LIGHTNING POTENTIAL WITH THE STRONGEST
STORMS...ALREADY SHOWN ON THE 15-MINUTE LIGHTNING PLOT EXTENDING
FROM VIRGINIA SOUTHWEST INTO THE MOUNTAINS.
OVERNIGHT...SUBSIDENCE AND GRADUAL CLEARING SHOULD TAKE PLACE BEHIND
THE DEEP CONVECTION. THE COLD FRONT SHOULD LAG THE DEEP
CONVECTION...AND WILL HOLD ONTO POPS FOR A SHORT PERIOD BEHIND THE
TIMING NOTED ABOVE. HOWEVER...NAM AND GFS BUFR SOUNDINGS SHOW AN
INCREASING STABLE AIR MASS WITH DIMINISHING LAPSE RATES ALOFT. WILL
HAVE POPS BELOW SLIGHT CHANCE THROUGHOUT CENTRAL NORTH CAROLINA BY
05Z...AND THIS COULD END UP BEING SLOW EVEN IN THE FAR SOUTHEAST
TOWARD KCTZ. LOWS IN THE LOWER TO MID 60S.
FRIDAY...IN THE TIGHT GRADIENT IN THE MORNING BEHIND THE DEPARTING
STRONG LOW...WIND GUSTS SHOULD INCREASE TO AROUND 20KT IN PLACES
WITH MIXING. THESE VALUES SUBSIDE DURING THE AFTERNOON AS 850MB AND
925MB WINDS DIMINISH. WHILE PRECIPITABLE WATER AND K INDICES SHOW A
BRIEF INCREASE FRIDAY AFTERNOON AHEAD OF ANOTHER MID-LEVEL SHORTWAVE
AND THE APPROACH OF THE LEFT EXIT REGION OF A 85KT 300MB AND 55KT
500MB JET...DIVERGENCE AT 850MB AND STABLE BUFR SOUNDINGS SHOULD
PRECLUDE ANY RELATIVELY DEEP CONVECTION. BUFR SOUNDINGS...HOWEVER...
NOTE THE POTENTIAL FOR SHALLOW HIGH SC OR LOW AC DURING THE
AFTERNOON...AND WILL AT LEAST FEATURE IN THE GRIDDED FORECAST A
PARTLY SUNNY SKY FOR MUCH OF THE AFTERNOON. HIGHS IN THE LOWER TO
MID 80S.
&&
.SHORT TERM /FRIDAY NIGHT AND SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...
BEHIND THE DEPARTING SYSTEM...CONDITIONS WILL DRY OUT AND COOL DOWN
THROUGH THE EARLY PART OF THE WEEKEND. SURFACE HIGH PRESSURE AND
RISING HEIGHTS ALOFT (ALTHOUGH THE CORE OF THE MID/UPPER HIGH WILL
REMAIN WEST OF OF THE REGION BEFORE FLATTENING OUT BY THE LATTER
HALF OF THE WEEKEND) WILL LEAD TO MORE SUNSHINE AND MOSTLY DRY
CONDITIONS THROUGH SATURDAY NIGHT. TEMPS SHOULD STAY SLIGHTLY BELOW
NORMAL...WITH HIGHS GENERALLY IN THE MID 80S. COMFORTABLE OVERNIGHT
LOWS ARE EXPECTED FRIDAY NIGHT...MOSTLY LOWER 60S...BUT SOME UPPER
50S WILL BE POSSIBLE...WITH A SLIGHT MODERATION FOR SATURDAY NIGHT
AS LOW LEVEL MOISTURE SLOWLY BEGINS TO RETURN.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 245 PM THURSDAY...
THE NEXT SYSTEM WILL APPROACH THE REGION EARLY NEXT WEEK...BUT THERE
ARE STILL SOME TIMING/STRENGTH ISSUES BETWEEN THE MODELS. AT THIS
TIME...IT APPEARS SUNDAY/SUNDAY NIGHT WILL REMAIN MOSTLY DRY AS THE
STORM SYSTEM REMAINS TO OUR NORTH AND WEST. BY MONDAY...WITH
INCREASING SOUTHWESTERLY FLOW...WE WILL REALLY BEGIN TO SEE OUR
MOISTURE RETURN...WITH PWAT VALUES RISING ABOVE 1.5 INCHES. THE
TRAILING COLD FRONT WILL STILL BE EAST OF THE AREA ON MONDAY...
THEREFORE AM EXPECTING MOSTLY DIURNALLY FORCED SHOWERS AND
THUNDERSTORMS. THE TRAILING FRONT LOOKS TO CROSS THE AREA SOMETIME
TUESDAY/TUESDAY NIGHT...THEREFORE THIS IS WHEN THE HIGHEST PRECIP
CHANCES WILL BE FOCUSED. THE FRONT LOOKS TO STALL SOMEWHERE NEAR THE
NC/SC BORDER FOR WEDNESDAY AND THURSDAY AND THIS WILL BE WHAT
ULTIMATELY DRIVES OUR PRECIP CHANCES FOR THE REMAINDER OF THE
FORECAST PERIOD. FOR NOW WILL KEEP SOME POPS (MOSTLY SLIGHT CHANCE)
IN FOR THIS TIME FRAME AND DUE TO THE PROXIMITY OF THE FRONT...THE
SOUTHERN PORTIONS OF THE FORECAST AREA WILL BE THE MOST LIKELY AREA
TO RECEIVE SOME PRECIP. TEMPS WILL BE NEAR NORMAL AHEAD OF THE
FRONT...WITH SLIGHTLY BELOW NORMAL TEMPS BEHIND THE FRONT.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 745 PM THURSDAY...
A LARGE AREA OF SHOWERS AND THUNDERSTORMS....SOME WITH WIND GUSTS IN
EXCESS OF 45 KTS CONTINUES TO SHIFT SOUTH AND EAST INTO THE SOUTHERN
PIEDMONT...SANDHILLS AND SOUTHERN COASTAL PLAIN. THE STRONGEST
CONVECTION REMAINS ON THE SOUTH AND EASTERN PERIPHERY OF THE
CONVECTION WITH THUNDERSTORMS LIKELY TO PERSIST NEAR FAYETTEVILLE
FOR ANOTHER HOUR OR SO WHILE THE THREAT OF THUNDERSTORMS HAS ENDED
AT THE REMAINING TAF LOCATIONS. SCATTERED SHOWERS MAY PERSIST INTO
THE MID EVENING HOURS WITH GENERALLY VFR CONDITIONS WITH A DECREASE
IN CLOUD COVER OVERNIGHT WITH PERIODS OF ALTO-STRATUS AND
ALTO-CUMULUS OVERNIGHT. WINDS WILL GRADUALLY BECOME WEST AND THEN
NORTHWEST OVERNIGHT AT 5 TO 10 KTS. FRIDAY SHOULD FEATURE VFR
CONDITIONS WITH SOME SCATTERED CUMULUS CLOUDS. NORTHWEST WINDS EARLY
FRIDAY AT AROUND 10KT WILL GUST UP TO 20 KTS AT TIMES AND BECOME
MORE NORTHERLY BY AFTERNOON.
LOOKING FURTHER AHEAD...FAIR WEATHER WITH VFR CONDITIONS WILL
CONTINUE THROUGH THE WEEKEND. A STORM SYSTEM WILL APPROACH LATE
MONDAY AND THEN MOVE ACROSS THE AREA LATE TUESDAY BRINGING A THREAT
OF SHOWERS AND THUNDERSTORMS ALONG WITH POSSIBLY SOME MORNING
STRATUS ON MONDAY AND TUESDAY MORNINGS. -BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SEC
NEAR TERM...DJF
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
315 PM EDT WED JUN 12 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL PROGRESS FROM
THE CENTRAL PLAINS INTO THE OHIO VALLEY TONIGHT...THEN MOVE ACROSS
THE MID ATLANTIC AND CAROLINAS ON THURSDAY AFTERNOON AND EVENING. A
COOLER AND DRIER AIR MASS WILL BUILD INTO THE REGION BEHIND THE COLD
FRONT FOR FRIDAY AND SATURDAY.
&&
.NEAR TERM /THIS AFTERNOON AND TONIGHT/...
AS OF 250 PM WEDNESDAY...
LATEST SFC ANALYSIS SHOWS COLD FRONT EXTENDED FROM NEAR KORD EAST
AND SOUTHEAST INTO THE NORTHERN CHESAPEAKE BAY. A BROAD SFC TROUGH
HAS SET UP OVER THE WESTERN CAROLINAS WITH A LIGHT SOUTHWESTERLY
SURFACE FLOW. SURFACE DEWPOINTS RANGE IN THE UPPER 60S IN THE
WESTERN PIEDMONT TO MID 60S FURTHER EAST WITH TEMPERATURES IN THE
UPPER 80S TO NEAR 90. THE AIR MASS IN THE WESTERN PIEDMONT IS
STRONGLY UNSTABLE WITH MLCAPE VALUES EXCEEDING 3000 J/KG WITH A
MODERATELY UNSTABLE AIRMASS FURTHER EAST.
WE HAVE BEEN CONCERNED ABOUT THE POTENTIAL FOR CONVECTION TO DEVELOP
IN OR UPSTREAM OF THIS AIRMASS AND THEN MOVE ACROSS CENTRAL NC. A
DISTURBANCE IN THE NW FLOW ALOFT MOVED THROUGH CENTRAL NC LATE THIS
MORNING WITH SOME BRIEF RIDGING ALOFT THIS AFTERNOON BEFORE ANOTHER
DISTURBANCE MOVES ACROSS SOUTHEAST VA AND NORTHEAST NC LATER THIS
EVENING. THE NAM AND TO A LESSER EXTENT RAP BUFR SOUNDINGS HAVE
NOTED A LOW LEVEL CAP THAT SHOULD LIMIT CONVECTIVE COVERAGE.
CONVECTION ALLOWING MODELS HAVE STRUGGLED WITH THE POTENTIAL FOR
CONVECTION TODAY GIVEN THE WEAKER FORCING AND MORE SUBTLE FEATURES.
THEY CURRENTLY PROVIDE A VARIETY OF SOLUTIONS THIS EVENING BUT THEIR
TREND IS FOR LESS COVERAGE WITH THE GREATEST CHANCE IN THE WESTERN
PIEDMONT THIS EVENING. WILL INCLUDE SLIGHT CHANCE POPS IN THE WEST
THIS EVENING BUT KEEP THE REST OF THE AREA DRY WITH FAIR SKIES.
EXPECT LOWS OVERNIGHT IN THE 68 TO 73 RANGE. -BLAES
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 315 PM WEDNESDAY...
...SEVERE WEATHER POSSIBLE LATE THURSDAY AFTERNOON AND EVENING...
A ROBUST SHORT WAVE TROUGH WILL MOVE ACROSS THE OHIO VALLEY ON
THURSDAY AND OFF THE MID ATLANTIC COAST ON THURSDAY EVENING. THE
ASSOCIATED SURFACE LOW WILL DEEPEN AS IT MOVES ACROSS THE
APPALACHIANS INTO THE NORTHERN CHESAPEAKE BAY AS THE TRAILING COLD
FRONT SLIDES ACROSS CENTRAL NC. THE AIR MASS AHEAD OF THE FRONT IS
EXPECTED TO BE MODERATELY TO NEARLY STRONGLY UNSTABLE WITH MID-LEVEL
LAPSE RATES OF AROUND 7 DEG C/KM. EXPECT A STOUT SOUTHWEST TO
WESTERLY LOW LEVEL FLOW DURING THE AFTERNOON WITH STRONGER MID LEVEL
WIND MAX OF 50+ KTS ROTATING INTO THE REGION. EXPECT ISOLATED
CONVECTION TO FIRE ACROSS THE WESTERN PIEDMONT DURING THE MID
AFTERNOON...INITIATED IN PART BY THE APPROACHING SFC TROUGH BUT
LIMITED IN COVERAGE FROM A NOTABLE DOWNSLOPE DRYING FLOW OFF THE
MOUNTAINS. CONVECTION IS LIKELY TO INTENSIFY AND SLOWLY GROW IN
COVERAGE AS IT APPROACHES THE US 1 CORRIDOR DURING THE LATE
AFTERNOON IN THE FORM OF ORGANIZED CONVECTION INCLUDING POSSIBLE
SUPERCELLS WITH DAMAGING WINDS AND POSSIBLY HAIL. AS THE CONVECTION
REACHES A MORE MOIST ENVIRONMENT THE CONVECTION WILL LIKELY GROW
UPSCALE INTO A SQUALL LINE AND BOWING FEATURE AS IT MOVES ACROSS THE
COASTAL PLAIN WITH THE POTENTIAL FOR WIDESPREAD DAMAGING WINDS. THE
GREATEST THREAT OF SEVERE WEATHER WILL LIKELY BE IN THE COASTAL
PLAIN BETWEEN 4 AND 9 WITH WIDESPREAD DAMAGING WINDS POSSIBLE.
HIGH TEMPERATURES ARE EXPECTED TO CLIMB INTO LOWER 90S NORTHWEST TO
MID 90S SOUTHEAST. THESE TEMPERATURES COMBINED WITH DEWPOINTS IN THE
MID TO POSSIBLY UPPER 60S WILL RESULT IN HEAT INDEX VALUES AROUND OR
JUST EXCEEDING 100 DEGREES. WILL ACCORDINGLY MENTION THIS IN THE
HWO. BEHIND THE COLD FRONT...LOW TEMPERATURES WILL FALL INTO THE
LOWER TO MID 60S BY FRIDAY MORNING. -BLAES
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 240 PM WEDNESDAY...
CONDITIONS WILL DRY OUT AND COOL DOWN BEHIND THE DEPARTING SYSTEM
FOR THE END OF THE WORK WEEK AND EARLY WEEKEND. THE STRONG MID/UPPER
LEVEL TROUGH WILL BE CROSSING THE AREA DURING THE DAY ON FRIDAY AND
VERY WELL COULD PRODUCE A COUPLE OF SHOWERS OR SOME SPRINKLES.
HOWEVER...THE DEEP MOISTURE WILL HAVE MOVED OFFSHORE...SO AM NOT
EXPECTING ENOUGH COVERAGE TO PUT ANY MENTION IN THE FORECAST. IF
ANYTHING DOES DEVELOP...IT SHOULD BE ACROSS THE EASTERN THIRD OF THE
FORECAST AREA WHERE SOME RESIDUAL MOISTURE (PWAT VALUES NEAR AN
INCH) MAY RESIDE.
THEN...SURFACE HIGH PRESSURE AND RISING HEIGHTS ALOFT (ALTHOUGH THE
CORE OF THE MID/UPPER HIGH WILL REMAIN WEST OF OF THE REGION BEFORE
FLATTENING OUT BY THE LATTER HALF OF THE WEEKEND) WILL LEAD TO MORE
SUNSHINE AND MOSTLY DRY CONDITIONS THROUGH MUCH OF THE WEEKEND.
TEMPS SHOULD STAY BELOW NORMAL (HIGHS IN THE LOW/MID 80S...OVERNIGHT
LOWS IN THE LOW 60S...WITH EVEN SOME UPPER 50S POSSIBLE) FRIDAY AND
SATURDAY...BEFORE MODIFYING ON SUNDAY AS THE SURFACE HIGH SHIFTS
OFFSHORE. THE NEXT SYSTEM LOOKS TO APPROACH THE REGION EARLY NEXT
WEEK...BUT THERE ARE STILL SOME TIMING/STRENGTH ISSUES BETWEEN THE
MODELS. AT THIS TIME...IT APPEARS A FRONT WILL MOVE THROUGH THE AREA
SOMETIME ON TUESDAY...WHICH IS WHEN THE BEST CHANCE OF RAIN WILL BE
FOCUSED. HOWEVER...INCREASING SOUTHWESTERLY FLOW WILL DRIVE OUR
MOISTURE BACK UP AND THEREFORE WILL HAVE SLIGHT CHANCE POPS FOR
MONDAY. TEMPS WILL BE NEAR NORMAL FOR THE BEGINNING ON NEXT WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 140 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE CURRENT TAF
PERIOD. THERE COULD BE AN ISOLATED SHOWER OR THUNDERSTORM THAT
DEVELOPS LATER THIS AFTERNOON...MOST LIKELY ACROSS THE WEST...BUT
CHANCES ARE TOO SMALL TO INCLUDE ANY MENTION IN THE TAFS.
OTHERWISE...SOUTHWESTERLY WINDS WILL INCREASE THURSDAY MORNING...
WITH GUSTS AROUND 25 KNOTS POSSIBLE. IT STILL APPEARS THAT THE
MAJORITY OF THE PRECIP WILL HOLD OFF UNTIL AFTER 18Z THURSDAY.
OUTLOOK...ADVERSE AVIATION CONDITIONS IN THE FORM OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE DAY
THURSDAY...LIKELY BEGINNING SHORTLY AFTER 18Z. ANY THUNDERSTORMS
THAT DEVELOP WILL BE CAPABLE OF PRODUCING DAMAGING SURFACE WIND
GUSTS IN EXCESS OF 50 KNOTS. AT THIS TIME...THE BEST CHANCE FOR
AFTERNOON CONVECTION AND SEVERE WEATHER WILL BE AT THE RDU/FAY/RWI
TERMINALS. GUSTY SOUTHWESTERLY WINDS (SEE ABOVE PARAGRAPH) WILL
SHIFT TO THE NORTHWEST IN THE WAKE OF A COLD FRONTAL PASSAGE
THURSDAY EVENING/NIGHT. EXPECT DRY/VFR CONDITIONS TO PREVAIL IN THE
WAKE OF THE FRONT FRIDAY THROUGH THE WEEKEND...WITH THE NEXT CHANCE
OF PRECIP RETURNING TO THE AREA EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...BLAES
LONG TERM...KRR
AVIATION...KRR/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
322 PM EDT WED JUN 12 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL PROGRESS FROM
THE CENTRAL PLAINS INTO THE OHIO VALLEY TONIGHT...THEN MOVE ACROSS
THE MID ATLANTIC AND CAROLINAS ON THURSDAY AFTERNOON AND EVENING. A
COOLER AND DRIER AIR MASS WILL BUILD INTO THE REGION BEHIND THE COLD
FRONT FOR FRIDAY AND SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 250 PM WEDNESDAY...
LATEST SFC ANALYSIS SHOWS COLD FRONT EXTENDED FROM NEAR KORD EAST
AND SOUTHEAST INTO THE NORTHERN CHESAPEAKE BAY. A BROAD SFC TROUGH
HAS SET UP OVER THE WESTERN CAROLINAS WITH A LIGHT SOUTHWESTERLY
SURFACE FLOW. SURFACE DEWPOINTS RANGE IN THE UPPER 60S IN THE
WESTERN PIEDMONT TO MID 60S FURTHER EAST WITH TEMPERATURES IN THE
UPPER 80S TO NEAR 90. THE AIR MASS IN THE WESTERN PIEDMONT IS
STRONGLY UNSTABLE WITH MLCAPE VALUES EXCEEDING 3000 J/KG WITH A
MODERATELY UNSTABLE AIRMASS FURTHER EAST.
WE HAVE BEEN CONCERNED ABOUT THE POTENTIAL FOR CONVECTION TO DEVELOP
IN OR UPSTREAM OF THIS AIRMASS AND THEN MOVE ACROSS CENTRAL NC. A
DISTURBANCE IN THE NW FLOW ALOFT MOVED THROUGH CENTRAL NC LATE THIS
MORNING WITH SOME BRIEF RIDGING ALOFT THIS AFTERNOON BEFORE ANOTHER
DISTURBANCE MOVES ACROSS SOUTHEAST VA AND NORTHEAST NC LATER THIS
EVENING. THE NAM AND TO A LESSER EXTENT RAP BUFR SOUNDINGS HAVE
NOTED A LOW LEVEL CAP THAT SHOULD LIMIT CONVECTIVE COVERAGE.
CONVECTION ALLOWING MODELS HAVE STRUGGLED WITH THE POTENTIAL FOR
CONVECTION TODAY GIVEN THE WEAKER FORCING AND MORE SUBTLE FEATURES.
THEY CURRENTLY PROVIDE A VARIETY OF SOLUTIONS THIS EVENING BUT THEIR
TREND IS FOR LESS COVERAGE WITH THE GREATEST CHANCE IN THE WESTERN
PIEDMONT THIS EVENING. WILL INCLUDE SLIGHT CHANCE POPS IN THE WEST
THIS EVENING BUT KEEP THE REST OF THE AREA DRY WITH FAIR SKIES.
EXPECT LOWS OVERNIGHT IN THE 68 TO 73 RANGE. -BLAES
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 315 PM WEDNESDAY...
SEVERE WEATHER POSSIBLE LATE THURSDAY AFTERNOON AND EVENING...
A ROBUST SHORT WAVE TROUGH WILL MOVE ACROSS THE OHIO VALLEY ON
THURSDAY AND OFF THE MID ATLANTIC COAST ON THURSDAY EVENING. THE
ASSOCIATED SURFACE LOW WILL DEEPEN AS IT MOVES ACROSS THE
APPALACHIANS INTO THE NORTHERN CHESAPEAKE BAY AS THE TRAILING COLD
FRONT SLIDES ACROSS CENTRAL NC. THE AIR MASS AHEAD OF THE FRONT IS
EXPECTED TO BE MODERATELY TO NEARLY STRONGLY UNSTABLE WITH MID-LEVEL
LAPSE RATES OF AROUND 7 DEG C/KM. EXPECT A STOUT SOUTHWEST TO
WESTERLY LOW LEVEL FLOW DURING THE AFTERNOON WITH STRONGER MID LEVEL
WIND MAX OF 50+ KTS ROTATING INTO THE REGION. EXPECT ISOLATED
CONVECTION TO FIRE ACROSS THE WESTERN PIEDMONT DURING THE MID
AFTERNOON...INITIATED IN PART BY THE APPROACHING SFC TROUGH BUT
LIMITED IN COVERAGE FROM A NOTABLE DOWNSLOPE DRYING FLOW OFF THE
MOUNTAINS. CONVECTION IS LIKELY TO INTENSIFY AND SLOWLY GROW IN
COVERAGE AS IT APPROACHES THE US 1 CORRIDOR DURING THE LATE
AFTERNOON IN THE FORM OF ORGANIZED CONVECTION INCLUDING POSSIBLE
SUPERCELLS WITH DAMAGING WINDS AND POSSIBLY HAIL. AS THE CONVECTION
REACHES A MORE MOIST ENVIRONMENT THE CONVECTION WILL LIKELY GROW
UPSCALE INTO A SQUALL LINE AND BOWING FEATURE AS IT MOVES ACROSS THE
COASTAL PLAIN WITH THE POTENTIAL FOR WIDESPREAD DAMAGING WINDS. THE
GREATEST THREAT OF SEVERE WEATHER WILL LIKELY BE IN THE COASTAL
PLAIN BETWEEN 4 AND 9 WITH WIDESPREAD DAMAGING WINDS POSSIBLE.
HIGH TEMPERATURES ARE EXPECTED TO CLIMB INTO LOWER 90S NORTHWEST TO
MID 90S SOUTHEAST. THESE TEMPERATURES COMBINED WITH DEWPOINTS IN THE
MID TO POSSIBLY UPPER 60S WILL RESULT IN HEAT INDEX VALUES AROUND OR
JUST EXCEEDING 100 DEGREES. WILL ACCORDINGLY MENTION THIS IN THE
HWO. BEHIND THE COLD FRONT...LOW TEMPERATURES WILL FALL INTO THE
LOWER TO MID 60S BY FRIDAY MORNING. -BLAES
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 240 PM WEDNESDAY...
CONDITIONS WILL DRY OUT AND COOL DOWN BEHIND THE DEPARTING SYSTEM
FOR THE END OF THE WORK WEEK AND EARLY WEEKEND. THE STRONG MID/UPPER
LEVEL TROUGH WILL BE CROSSING THE AREA DURING THE DAY ON FRIDAY AND
VERY WELL COULD PRODUCE A COUPLE OF SHOWERS OR SOME SPRINKLES.
HOWEVER...THE DEEP MOISTURE WILL HAVE MOVED OFFSHORE...SO AM NOT
EXPECTING ENOUGH COVERAGE TO PUT ANY MENTION IN THE FORECAST. IF
ANYTHING DOES DEVELOP...IT SHOULD BE ACROSS THE EASTERN THIRD OF THE
FORECAST AREA WHERE SOME RESIDUAL MOISTURE (PWAT VALUES NEAR AN
INCH) MAY RESIDE.
THEN...SURFACE HIGH PRESSURE AND RISING HEIGHTS ALOFT (ALTHOUGH THE
CORE OF THE MID/UPPER HIGH WILL REMAIN WEST OF OF THE REGION BEFORE
FLATTENING OUT BY THE LATTER HALF OF THE WEEKEND) WILL LEAD TO MORE
SUNSHINE AND MOSTLY DRY CONDITIONS THROUGH MUCH OF THE WEEKEND.
TEMPS SHOULD STAY BELOW NORMAL (HIGHS IN THE LOW/MID 80S...OVERNIGHT
LOWS IN THE LOW 60S...WITH EVEN SOME UPPER 50S POSSIBLE) FRIDAY AND
SATURDAY...BEFORE MODIFYING ON SUNDAY AS THE SURFACE HIGH SHIFTS
OFFSHORE. THE NEXT SYSTEM LOOKS TO APPROACH THE REGION EARLY NEXT
WEEK...BUT THERE ARE STILL SOME TIMING/STRENGTH ISSUES BETWEEN THE
MODELS. AT THIS TIME...IT APPEARS A FRONT WILL MOVE THROUGH THE AREA
SOMETIME ON TUESDAY...WHICH IS WHEN THE BEST CHANCE OF RAIN WILL BE
FOCUSED. HOWEVER...INCREASING SOUTHWESTERLY FLOW WILL DRIVE OUR
MOISTURE BACK UP AND THEREFORE WILL HAVE SLIGHT CHANCE POPS FOR
MONDAY. TEMPS WILL BE NEAR NORMAL FOR THE BEGINNING ON NEXT WEEK.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
AS OF 140 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE CURRENT TAF
PERIOD. THERE COULD BE AN ISOLATED SHOWER OR THUNDERSTORM THAT
DEVELOPS LATER THIS AFTERNOON...MOST LIKELY ACROSS THE WEST...BUT
CHANCES ARE TOO SMALL TO INCLUDE ANY MENTION IN THE TAFS.
OTHERWISE...SOUTHWESTERLY WINDS WILL INCREASE THURSDAY MORNING...
WITH GUSTS AROUND 25 KNOTS POSSIBLE. IT STILL APPEARS THAT THE
MAJORITY OF THE PRECIP WILL HOLD OFF UNTIL AFTER 18Z THURSDAY.
OUTLOOK...ADVERSE AVIATION CONDITIONS IN THE FORM OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE DAY
THURSDAY...LIKELY BEGINNING SHORTLY AFTER 18Z. ANY THUNDERSTORMS
THAT DEVELOP WILL BE CAPABLE OF PRODUCING DAMAGING SURFACE WIND
GUSTS IN EXCESS OF 50 KNOTS. AT THIS TIME...THE BEST CHANCE FOR
AFTERNOON CONVECTION AND SEVERE WEATHER WILL BE AT THE RDU/FAY/RWI
TERMINALS. GUSTY SOUTHWESTERLY WINDS (SEE ABOVE PARAGRAPH) WILL
SHIFT TO THE NORTHWEST IN THE WAKE OF A COLD FRONTAL PASSAGE
THURSDAY EVENING/NIGHT. EXPECT DRY/VFR CONDITIONS TO PREVAIL IN THE
WAKE OF THE FRONT FRIDAY THROUGH THE WEEKEND...WITH THE NEXT CHANCE
OF PRECIP RETURNING TO THE AREA EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...BLAES
LONG TERM...KRR
AVIATION...KRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
300 PM EDT WED JUN 12 2013
.SYNOPSIS...
HOT TEMPERATURES ARE EXPECTED THIS AFTERNOON AND AGAIN THURSDAY AS
AN UPPER RIDGE MOVES ACROSS THE REGION. A FEW THUNDERSTORMS MAY
DEVELOP INLAND LATE THIS AFTERNOON. MEANWHILE...A RELATIVELY STRONG
COLD FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT WITH A GOOD
CHANCE OF STRONG TO SEVERE THUNDERSTORMS. DRY WEATHER IS EXPECTED
INTO THE WEEKEND. ANOTHER COLD FRONT WILL REACH THE CAROLINAS EARLY
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 245 PM WEDNESDAY...VERY HOT DAY CONTINUES ACROSS THE AREA WITH
MOST LOCATIONS INTO THE LOW 90S...AND SOME MID 90S WELL INLAND. THIS
HAS...IN ESSENCE...CREATED AN ENVIRONMENT FAVORABLE FOR CONVECTION
THIS AFTN. HOWEVER...EVEN WITH AMPLE SURFACE INSTABILITY...EVEN CU
HAS HAD A DIFFICULT TIME DEVELOPING. THIS IS LIKELY DUE TO WARMING
850MB TEMPS...PRODUCING A LID THROUGH WHICH PARCELS ARE STRUGGLING
TO PENETRATE. THIS JIVES WELL WITH PREVIOUS THINKING THAT WARMING IN
THE MID LEVELS WILL SUPPRESS MUCH ACTIVITY TODAY.
LATEST HIGH-RES GUIDANCE IS COMING INTO MUCH BETTER AGREEMENT THAT
CONVECTION OVER THE MOUNTAINS WILL RACE SOUTHWARD AND WEAKEN THIS
EVE/EARLY TONIGHT...REMAINING PRIMARILY WEST OF THE CWA. WILL NOT
COMPLETELY RULE OUT SOME TSTMS CLIPPING THE WESTERN PORTIONS OF THE
AREA BEFORE NOCTURNAL COOLING OCCURS TONIGHT...AND HAVE CONTINUED
SCHC POP FOR THE I-95 COUNTIES AND WEST...BUT ANY ACTIVITY WILL BE
ISOLATED.
AS HIGH PRESSURE REMAINS OFFSHORE TONIGHT AND GRADIENT BEGINS TO
TIGHTEN...SW WINDS WILL INCREASE JUST OFF THE SURFACE...WHICH WILL
KEEP WINDS FROM FULLY DECOUPLING. THIS WILL KEEP TEMPS FROM FALLING
TOO MUCH TONIGHT...AND MINS WILL BE HELD WELL ABOVE NORMAL FOR
MID-JUNE...MID TO UPPER 70S FOR LOWS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 245 PM WEDNESDAY...TWO SIGNIFICANT ISSUES TO DEAL WITH DURING
THE SHORT TERM PERIOD INCLUDING HIGH HEAT INDICES AND THE POTENTIAL
FOR A SEVERE WEATHER EVENT LATE THURSDAY AFTERNOON AND THURSDAY
EVENING. OVERALL FRIDAY WILL BE A NICE DAY WITH COOLER/NEAR NORMAL
TEMPS AND NO POPS.
AS FOR THURSDAY...HIGH TEMPERATURES RANGING FROM THE MID TO UPPER
90S INLAND TO NEAR 90 COAST COUPLED WITH HIGH HUMIDITY WILL RESULT
IN HEAT INDICES IN THE 99-103F RANGE. FAVORED A BLEND TOWARD THE
WARMER MAV NUMBERS FOR THE INLAND LOCATIONS...ESPECIALLY GIVEN T1
NUMBERS SUGGEST UPPER 90S. HOWEVER...IN REGARDS TO A HEAT ADVISORY
THINK MIXING WILL MOST LIKELY RESULT IN LOWER DEWPOINTS THAN WHAT
GUIDANCE INDICATES...THUS THE FORECAST IS FOR SUB-HEAT ADVISORY
CONDITIONS AT THIS TIME. ALSO NOTE...THE DEWPOINT SENSOR AT
KINGSTREE (KCKI) IS MUCH HIGHER THAN THE SURROUNDING OBS MAKING THE
DATE THERE SUSPECT.
SPC HAS PLACED THE ENTIRE FORECAST AREA IN A SLIGHT RISK FOR
TOMORROW WITH THE OVERALL PROBABILITIES TRENDING HIGHER COMPARED TO
THE PREVIOUS OUTLOOK. A SHORT-WAVE WILL PUSH ACROSS THE MID-ATLANTIC
STATES DURING THE DAY WHILE THE LFQ OF AN UPPER JET BECOMES FOCUSED
ACROSS THE REGION. IN ADDITION...EXPECT AN ABUNDANCE OF INSTABILITY
WITH STRONG HEATING DURING THE DAY. ARW OUTPUT SUGGESTS A SQUALL
LINE PUSHING THROUGH LATER IN THE DAY AND INTO THE EVENING AT THE
COAST. EXPECTING THE PRIMARY THREAT TO BE FROM DAMAGING WINDS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 245 PM WEDNESDAY...AN EAST COAST TROUGH WILL HAVE MOVED WELL
OFFSHORE BY THE START OF THE PERIOD. A LARGE BUBBLE OF HIGH PRESSURE
ALOFT ACROSS THE CENTRAL GULF COAST AND RIDGING NORTHWARD INTO
CANADA WILL BUILD ACROSS THE EASTERN CAROLINAS DURING THE WEEKEND...
BRINGING DRY WEATHER. AT THE SURFACE...HIGH PRESSURE OF CANADIAN
ORIGIN...WILL BUILD OVERHEAD. NORTH WINDS WILL BRING A MUCH DRIER
AND COOLER AIRMASS. THE HIGH WILL SHIFT OFFSHORE ON SUN AND RIDGE
BACK ACROSS THE EASTERN CAROLINAS ON MON...ALLOWING A SOUTHWEST
RETURN FLOW TO DEVELOP WHICH WILL BRING A RETURN TO MORE MUGGY
CONDITIONS AND HIGHER TEMPERATURES.
A SHORTWAVE RIDING OVER THE TOP OF THE RIDGE WILL HELP TO FLATTEN IT
EARLY NEXT WEEK AND THIS WILL HELP DRIVE A COLD FRONT AT THE SURFACE
TOWARD THE SOUTHEAST COAST. BY TUE...THIS FRONT SHOULD BE CLOSE
ENOUGH TO BRING A RISK FOR SHOWERS AND THUNDERSTORMS AS A TROUGH
SLUGGISHLY ATTEMPTS TO BUILD DOWN THE EAST COAST. HIGH PRESSURE MAY
SURGE DOWN THE EAST COAST BY WED NIGHT...HELPING TO DRIVE THE FRONT
THROUGH THE AREA.
PRECIPITABLE WATER VALUES CLIMB FROM LESS THAN AN INCH ON MON TO TWO
INCHES TUE THROUGH WED AS THE DRY AIR IN THE MID LEVELS QUICKLY
ERODES. MIXED LAYER CAPE VALUES ARE EXPECTED TO REACH NEAR 1000 J/KG
AND UP TO 1400 J/KG INLAND TUE AFTERNOON AND ARE A LITTLE HIGHER
ACROSS THE FORECAST AREA ON WED. WILL INCLUDE A LIKELIHOOD FOR
SHOWERS AND THUNDERSTORMS FOR A PORTION OF OUR INLAND ZONES TUE
AFTERNOON AND EVE AS A PRE-FRONTAL TROUGH SHOULD ACT TO FOCUS AND
LIFT THE INCREASING MOISTURE...SCATTERED COVERAGE AS YOU NEAR THE
COAST AND ALONG THE PINNED SEABREEZE BOUNDARY. WILL FAVOR SLIGHTLY
HIGHER POPS AT THE COAST THAN INLAND ON WED...BUT CAP AT HIGH CHANCE
FOR NOW.
TEMPERATURES WILL BE SEASONABLE THROUGH THE PERIOD...MID AND UPPER
80S...BUT KNOCKING ON THE 90 DEGREE DOOR EARLY NEXT WEEK...
ESPECIALLY INLAND. LOWS WILL BE COOLEST SAT NIGHT...MID 60S TO NEAR
70 AT THE COAST. FOR THE REMAINDER OF THE PERIOD...LOWS WILL BE
AROUND 70 TO THE MID 70S AS THE DEWPOINTS CREEP HIGHER.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...MODELS ARE NOT IN GOOD AGREEMENT WITH REGARDS TO
CONVECTION THIS AFTERNOON. THE HRRR HAS ABSOLUTELY NOTHING...WHILE
THE WRF AS SCATTERED CONVECTION OVER ABOUT A THIRD OF THE CWA. THINK
THERE WILL BE ISOLATED CB`S...BUT NOT ENOUGH COVERAGE FOR A VCTS
MENTION. SOUTHWEST FLOW WILL BE MORE SOUTH SOUTHWEST AND STRONGER AT
THE COASTAL TERMINALS DUE TO THE RESULTANT. LIGHT WINDS TONIGHT WITH
A REASONABLE CHANCE FOR A COUPLE OF HOURS OF FOG AFTER 09Z.
THURSDAY...CONTINUED SOUTHWEST FLOW WITH MAINLY SCATTERED HIGH
CLOUDS. ANY CONVECTION WILL HOLD OFF UNTIL THE END OF THE FORECAST
VALID PERIOD.
EXTENDED OUTLOOK...ISOLATED SHOWERS/THUNDERSTORMS WITH TEMPO PERIODS
OF MVFR/IFR POSSIBLE THURSDAY EVENING INTO FRIDAY MORNING. MORNING
FOG POSSIBLE SUNDAY AND MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 245 PM WEDNESDAY...CONTINUED SW WINDS AROUND OFFSHORE HIGH
PRESSURE WILL KEEP SW WINDS AND A SW WIND CHOP PREDOMINANT OVER THE
WATERS. SEAS CURRENTLY 2-4 FT WILL REMAIN STATUS QUO THROUGH THE
PERIOD...WITH SW WINDS OF 10-15 KTS PERSISTENT. THE EXCEPTION TO
THIS WILL BE WITHIN THE INNER FEW NM IN THE SEA BREEZE
BOUNDARY...WITH A SLIGHTLY BACKING TO SOUTH WILL OCCUR AS WELL AS AN
INCREASE IN SPEEDS...WITH GUSTS UP TO 20 KTS. SEAS WILL REMAIN 2-4
FT IN THIS ZONE...BUT WILL BECOME MORE CHOPPY THANKS TO SHORTER
PERIODS. SEA BREEZE WINDS WILL EASE AFTER SUNSET...ALLOWING FOR
NEAR-SHORE SEAS TO FALL BACK TO AROUND 2 FT INTO THURSDAY MORNING.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 245 PM WEDNESDAY...INCREASING SOUTHWESTERLY FLOW THURSDAY WILL
RESULT IN MARGINAL SMALL CRAFT CONDITIONS FOR THE CAPE FEAR WATERS
FROM THE AFTERNOON INTO THE EVENING AHEAD OF AN AREA OF CONVECTION
EXPECTED TO CROSS THE WATERS. PLAN TO HEADLINE SMALL CRAFT SHOULD
EXERCISE CAUTION FOR THE LONG BAY COASTAL WATERS. THE FLOW WILL VEER
TO A NORTHERLY DIRECTION BY FRIDAY MORNING AS HIGH PRESSURE BUILDS
ACROSS THE AREA. SPEEDS WILL FURTHER DIMINISH BY FRIDAY EVENING.
SEAS WILL PEAK AT MARGINAL SMALL CRAFT THRESHOLDS FOR THE OUTER
COASTAL WATERS THURSDAY AFTERNOON AND EVENING...THEN GRADUALLY
SUBSIDE THROUGH THE LATTER HALF OF THE SHORT TERM PERIOD.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 245 PM WEDNESDAY...LIGHT WINDS ON SAT WILL SETTLE ON SOUTH
DURING THE AFTERNOON AND EVE AND BECOME SW ON SUN AS HIGH PRESSURE
MOVES OFFSHORE. SW WINDS WILL CONTINUE FOR THE REMAINDER OF THE
PERIOD...INCREASING LATE MON AND MON NIGHT AS THE PRESSURE GRADIENT
TIGHTENS SLIGHTLY IN RESPONSE TO A DEVELOPING PIEDMONT TROUGH. WINDS
WILL BE 15 KT OR LESS THROUGH THE WEEKEND...HIGHEST LATE DAY AND
THROUGH THE EVE ACROSS THE NEAR SHORE WATERS DUE TO SEABREEZE
INFLUENCES. SW WINDS WILL INCREASE TO AROUND 15 KT THROUGHOUT LATE
MON AND MON NIGHT. SEAS WILL BE 2 TO 3 FT THROUGH THE WEEKEND...WITH
SOME 4 FT SEAS DEVELOPING ACROSS THE OUTER WATERS LATE MON AND MON
NIGHT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 PM THURSDAY TO 5 AM EDT FRIDAY
FOR AMZ250-252.
&&
$$
NEAR TERM...JDW
SHORT TERM...SRP
LONG TERM...RJD
AVIATION...DL/JDW
AREA FORECAST DISCUSSION
NWS RALEIGH NC
250 PM EDT WED JUN 12 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL PROGRESS FROM
THE CENTRAL PLAINS INTO THE OHIO VALLEY TONIGHT...THEN MOVE ACROSS
THE MID ATLANTIC AND CAROLINAS ON THURSDAY AFTERNOON AND EVENING. A
COOLER AND DRIER AIR MASS WILL BUILD INTO THE REGION BEHIND THE COLD
FRONT FOR FRIDAY AND SATURDAY.
&&
.NEAR TERM /THIS AFTERNOON AND TONIGHT/...
AS OF 250 PM WEDNESDAY...
LATEST SFC ANALYSIS SHOWS COLD FRONT EXTENDED FROM NEAR KORD EAST
AND SOUTHEAST INTO THE NORTHERN CHESAPEAKE BAY. A BROAD SFC TROUGH
HAS SET UP OVER THE WESTERN CAROLINAS WITH A LIGHT SOUTHWESTERLY
SURFACE FLOW. SURFACE DEWPOINTS RANGE IN THE UPPER 60S IN THE
WESTERN PIEDMONT TO MID 60S FURTHER EAST WITH TEMPERATURES IN THE
UPPER 80S TO NEAR 90. THE AIR MASS IN THE WESTERN PIEDMONT IS
STRONGLY UNSTABLE WITH MLCAPE VALUES EXCEEDING 3000 J/KG WITH A
MODERATELY UNSTABLE AIRMASS FURTHER EAST.
WE HAVE BEEN CONCERNED ABOUT THE POTENTIAL FOR CONVECTION TO DEVELOP
IN OR UPSTREAM OF THIS AIRMASS AND THEN MOVE ACROSS CENTRAL NC. A
DISTURBANCE IN THE NW FLOW ALOFT MOVED THROUGH CENTRAL NC LATE THIS
MORNING WITH SOME BRIEF RIDGING ALOFT THIS AFTERNOON BEFORE ANOTHER
DISTURBANCE MOVES ACROSS SOUTHEAST VA AND NORTHEAST NC LATER THIS
EVENING. THE NAM AND TO A LESSER EXTENT RAP BUFR SOUNDINGS HAVE
NOTED A LOW LEVEL CAP THAT SHOULD LIMIT CONVECTIVE COVERAGE.
CONVECTION ALLOWING MODELS HAVE STRUGGLED WITH THE POTENTIAL FOR
CONVECTION TODAY GIVEN THE WEAKER FORCING AND MORE SUBTLE FEATURES.
THEY CURRENTLY PROVIDE A VARIETY OF SOLUTIONS THIS EVENING BUT THEIR
TREND IS FOR LESS COVERAGE WITH THE GREATEST CHANCE IN THE WESTERN
PIEDMONT THIS EVENING. WILL INCLUDE SLIGHT CHANCE POPS IN THE WEST
THIS EVENING BUT KEEP THE REST OF THE AREA DRY WITH FAIR SKIES.
EXPECT LOWS OVERNIGHT IN THE 68 TO 73 RANGE. -BLAES
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 AM WEDNESDAY...
...SEVERE WEATHER EXPECTED THURSDAY AFTERNOON AND EVENING...
THURSDAY AND THURSDAY NIGHT:
AN UNSEASONABLY AMPLIFIED PATTERN WILL PERSIST ON THU...
CHARACTERIZED BY A STRONG UPPER LEVEL RIDGE OVER THE CENTRAL CONUS
AND NW FLOW ALOFT DOWNSTREAM ACROSS THE TN/OH VALLEY AND
MID-ATLANTIC. ROBUST SHORTWAVE ENERGY (AND AN ATTENDANT SFC LOW) IN
THE OH VALLEY THU MORNING WILL TRACK EAST ACROSS THE MID-ATLANTIC
THU AFTERNOON AND EVENING. MODERATE INSTABILITY (1500-2500 J/KG
MLCAPE) IS EXPECTED ACROSS CENTRAL NC...IN ASSOCIATION WITH STEEP
(6.5-7.5 C/KM) MID-LEVEL LAPSE RATES AND SEASONABLE BOUNDARY LAYER
MOISTURE. STRENGTHENING WESTERLY FLOW ALOFT IN ADVANCE OF THE
SHORTWAVE WILL RESULT IN 0-6 KM SHEAR ON THE ORDER OF 25-40 KT
(STRONGEST NORTH)...SUFFICIENT FOR ORGANIZED CONVECTION...ESPECIALLY
IN THE PRESENCE OF MODERATE INSTABILITY AND STEEP MID-LEVEL LAPSE
RATES.
SOME UNCERTAINTY PERSISTS WITH REGARD TO THE SPECIFICS OF THIS
SYSTEM GIVEN SMALL VARIANCES IN TIMING AND ONGOING CONVECTION /MCS
ACTIVITY/ EXPECTED TO TRACK INTO THE APPALACHIANS THU MORNING. GIVEN
EXCELLENT SYNOPTIC FORCING...MODERATE DESTABILIZATION AND FAVORABLE
DEEP-LAYER SHEAR...A SIGNIFICANT SEVERE WEATHER EPISODE IS EXPECTED
ACROSS THE REGION THU AFTERNOON AND EVENING. FROM A PATTERN
RECOGNITION STANDPOINT...THE EXPECTED ENVIRONMENT IN CENTRAL NC
WOULD PRIMARILY SUPPORT AN ENHANCED THREAT OF DAMAGING WINDS GIVEN
UNIDIRECTIONAL DEEP-LAYER SHEAR...SPEEDY MID-LEVEL FLOW AND STRONG
EVAP COOLING POTENTIAL ASSOC/W THE MODIFIED EML IN PLACE AND
INVERTED-V PROFILES IN THE BOUNDARY LAYER. W/REGARD TO CONVECTIVE
MODE...EXPECT A RELATIVELY NARROW WINDOW FOR ANY DISCRETE CONVECTION
PRIOR TO RAPID UPSCALE GROWTH INTO AN MCS GIVEN HIGH DCAPE /STRONG
COLD POOLS/ AND MODERATE INSTABILITY. THE LATEST GUIDANCE SUGGESTS
THAT THE TORNADO THREAT WOULD LIKELY REMAIN WELL TO THE NORTH (I.E.
NORTHERN VA/MD/PA/NJ) AND OTHER PORTIONS OF THE MID-ATLANTIC
COAST...IN CLOSER VICINITY TO THE SFC LOW TRACK AND WARM FRONT AND
BETTER LOW-LEVEL DIRECTIONAL SHEAR. WITH EXPECTED MCS ACTIVITY AND
OUTFLOW PROGRESSING INTO THE MOUNTAINS THU MORNING AND A POTENTIAL
FOR HINDERED DESTABILIZATION MID/LATE THU MORNING INTO EARLY THU
AFTERNOON IN THE FAR W/NW PIEDMONT...HAVE DECREASED PRECIP CHANCES
TO 40% IN THAT AREA...WITH PRECIP CHANCES AT 50% IN VICINITY OF THE
HWY 1 CORRIDOR AND 60-70% EAST OF INTERSTATE 95. EXPECT THE BEST
SEVERE THREAT EAST OF HWY 1 AT THIS TIME. HIGHS LOWER TO MID
90S...WARMEST EAST...THOUGH CONFIDENCE IS LOWER THAN NORMAL GIVEN
UNCERTAINTY W/REGARD TO MCS ACTIVITY/CLOUD COVER THAT MAY PROGRESS
INTO WESTERN PORTIONS OF THE STATE IN THE MORNING. EXPECT LOWS THU
NIGHT IN THE MID TO UPPER 60S IN THE WAKE OF A COLD FRONTAL PASSAGE
AS THE SHORTWAVE AND ATTENDANT SFC LOW TRACK OFFSHORE THE
MID-ATLANTIC. -VINCENT
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 240 PM WEDNESDAY...
CONDITIONS WILL DRY OUT AND COOL DOWN BEHIND THE DEPARTING SYSTEM
FOR THE END OF THE WORK WEEK AND EARLY WEEKEND. THE STRONG MID/UPPER
LEVEL TROUGH WILL BE CROSSING THE AREA DURING THE DAY ON FRIDAY AND
VERY WELL COULD PRODUCE A COUPLE OF SHOWERS OR SOME SPRINKLES.
HOWEVER...THE DEEP MOISTURE WILL HAVE MOVED OFFSHORE...SO AM NOT
EXPECTING ENOUGH COVERAGE TO PUT ANY MENTION IN THE FORECAST. IF
ANYTHING DOES DEVELOP...IT SHOULD BE ACROSS THE EASTERN THIRD OF THE
FORECAST AREA WHERE SOME RESIDUAL MOISTURE (PWAT VALUES NEAR AN
INCH) MAY RESIDE.
THEN...SURFACE HIGH PRESSURE AND RISING HEIGHTS ALOFT (ALTHOUGH THE
CORE OF THE MID/UPPER HIGH WILL REMAIN WEST OF OF THE REGION BEFORE
FLATTENING OUT BY THE LATTER HALF OF THE WEEKEND) WILL LEAD TO MORE
SUNSHINE AND MOSTLY DRY CONDITIONS THROUGH MUCH OF THE WEEKEND.
TEMPS SHOULD STAY BELOW NORMAL (HIGHS IN THE LOW/MID 80S...OVERNIGHT
LOWS IN THE LOW 60S...WITH EVEN SOME UPPER 50S POSSIBLE) FRIDAY AND
SATURDAY...BEFORE MODIFYING ON SUNDAY AS THE SURFACE HIGH SHIFTS
OFFSHORE. THE NEXT SYSTEM LOOKS TO APPROACH THE REGION EARLY NEXT
WEEK...BUT THERE ARE STILL SOME TIMING/STRENGTH ISSUES BETWEEN THE
MODELS. AT THIS TIME...IT APPEARS A FRONT WILL MOVE THROUGH THE AREA
SOMETIME ON TUESDAY...WHICH IS WHEN THE BEST CHANCE OF RAIN WILL BE
FOCUSED. HOWEVER...INCREASING SOUTHWESTERLY FLOW WILL DRIVE OUR
MOISTURE BACK UP AND THEREFORE WILL HAVE SLIGHT CHANCE POPS FOR
MONDAY. TEMPS WILL BE NEAR NORMAL FOR THE BEGINNING ON NEXT WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 140 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE CURRENT TAF
PERIOD. THERE COULD BE AN ISOLATED SHOWER OR THUNDERSTORM THAT
DEVELOPS LATER THIS AFTERNOON...MOST LIKELY ACROSS THE WEST...BUT
CHANCES ARE TOO SMALL TO INCLUDE ANY MENTION IN THE TAFS.
OTHERWISE...SOUTHWESTERLY WINDS WILL INCREASE THURSDAY MORNING...
WITH GUSTS AROUND 25 KNOTS POSSIBLE. IT STILL APPEARS THAT THE
MAJORITY OF THE PRECIP WILL HOLD OFF UNTIL AFTER 18Z THURSDAY.
OUTLOOK...ADVERSE AVIATION CONDITIONS IN THE FORM OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE DAY
THURSDAY...LIKELY BEGINNING SHORTLY AFTER 18Z. ANY THUNDERSTORMS
THAT DEVELOP WILL BE CAPABLE OF PRODUCING DAMAGING SURFACE WIND
GUSTS IN EXCESS OF 50 KNOTS. AT THIS TIME...THE BEST CHANCE FOR
AFTERNOON CONVECTION AND SEVERE WEATHER WILL BE AT THE RDU/FAY/RWI
TERMINALS. GUSTY SOUTHWESTERLY WINDS (SEE ABOVE PARAGRAPH) WILL
SHIFT TO THE NORTHWEST IN THE WAKE OF A COLD FRONTAL PASSAGE
THURSDAY EVENING/NIGHT. EXPECT DRY/VFR CONDITIONS TO PREVAIL IN THE
WAKE OF THE FRONT FRIDAY THROUGH THE WEEKEND...WITH THE NEXT CHANCE
OF PRECIP RETURNING TO THE AREA EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...VINCENT
LONG TERM...KRR
AVIATION...KRR/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
243 PM EDT WED JUN 12 2013
.SYNOPSIS...
A DEEPENING LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL
PROGRESS FROM THE CENTRAL PLAINS INTO THE OHIO VALLEY TONIGHT...THEN
TRACK EAST THROUGH THE MID ATLANTIC AND CAROLINAS ON THURSDAY. DRY
HIGH PRESSURE WILL BUILD INTO THE REGION IN THE WAKE OF THE COLD
FRONT THURSDAY NIGHT AND FRIDAY.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 1100 AM WEDNESDAY...
AN UPPER LEVEL RIDGE CENTERED OVER THE SOUTHERN PLAINS WILL
STRENGTHEN SOMEWHAT TODAY WITH MINOR HEIGHT RISES ACROSS THE MID
ATLANTIC. SMALL AMPLITUDE DISTURBANCES IN NW FLOW ALOFT ARE
EXPECTED TO TRACK SOUTHEAST INTO THE CAROLINAS THIS AFTERNOON
THROUGH TONIGHT WHILE A MUCH MORE POTENT SHORTWAVE CENTERED ATOP THE
RIDGE IN THE NORTHERN PLAINS THIS MORNING WILL TRACK INTO THE TN/OH
VALLEY TONIGHT. A WEAK SURFACE TROUGH ACROSS CENTRAL NC WILL PERSIST
ACROSS WESTERN/CENTRAL NC WITH A LIGHT SW SURFACE WIND BECOMING MORE
WESTERLY THIS AFTERNOON.
WE HAVE BEEN MONITORING A REGION OF ISOLATED CONVECTION IN THE
CENTRAL APPALACHIANS THAT DEVELOPED OVERNIGHT. THE FACT THIS
DEVELOPED DURING AN ATYPICAL TIME OF DAY SUGGEST THAT SOME MESOSCALE
FORCING IS LIKELY DRIVING THIS AND IT APPEARS TO BE DEVELOPING IN A
REGION OF WARM ADVECTION AND ENHANCED MID LEVEL FLOW. CONVECTION
ALLOWING MODELS PROVIDE A VARIETY OF SOLUTIONS WITH THIS CONVECTION:
THE 00 UTC ARW/NMM HI RES WINDOWS SUGGEST SOME OF THE CONVECTION
WILL PERSIST AND GROW INTO A CLUSTER OF CONVECTION AROUND MIDDAY AND
SWEEP SOUTHEAST ACROSS THE PIEDMONT WHILE THE HRRR SUGGESTS THAT
ONGOING CONVECTION WILL WEAKEN WITH LITTLE ADDITIONAL REDEVELOPMENT
LIKELY. WITH RECENT RADAR TRENDS SUGGESTING A DECREASE IN
INTENSITY/COVERAGE OF THE CONVECTION AND THE PERSISTENCE OF A MID
LEVEL CAPPING INVERSION...HAVE OPTED TO REMOVE SLIGHT CHANCE POPS IN
THE EAST THIS AFTERNOON AND HIGHLIGHT THE FAR WEST DURING THE EARLY
TO MID AFTERNOON PERIOD FOR SLIGHT CHC POPS...ESPECIALLY ALONG THE
YADKIN RIVER.
CONVECTIVE DEBRIS CLOUDS ARE ALREADY SPREADING ACROSS THE WESTERN
PIEDMONT AND WILL SWEEP INTO THE EASTERN PIEDMONT AND SANDHILLS THIS
AFTERNOON. THE THICKER CLOUDS CLOSE TO THE YADKIN SHOULD BE
SUFFICIENT ENOUGH TO RETARD TEMPERATURES A DEGREE OR TWO. BUT WE
STILL EXPECT HIGHS TO RANGE IN THE 88 TO 95 RANGE TODAY. EXPECT LOWS
OVERNIGHT IN THE 69 TO 73 RANGE. -BLAES/VINCENT
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 AM WEDNESDAY...
...SEVERE WEATHER EXPECTED THURSDAY AFTERNOON AND EVENING...
THURSDAY AND THURSDAY NIGHT:
AN UNSEASONABLY AMPLIFIED PATTERN WILL PERSIST ON THU...
CHARACTERIZED BY A STRONG UPPER LEVEL RIDGE OVER THE CENTRAL CONUS
AND NW FLOW ALOFT DOWNSTREAM ACROSS THE TN/OH VALLEY AND
MID-ATLANTIC. ROBUST SHORTWAVE ENERGY (AND AN ATTENDANT SFC LOW) IN
THE OH VALLEY THU MORNING WILL TRACK EAST ACROSS THE MID-ATLANTIC
THU AFTERNOON AND EVENING. MODERATE INSTABILITY (1500-2500 J/KG
MLCAPE) IS EXPECTED ACROSS CENTRAL NC...IN ASSOCIATION WITH STEEP
(6.5-7.5 C/KM) MID-LEVEL LAPSE RATES AND SEASONABLE BOUNDARY LAYER
MOISTURE. STRENGTHENING WESTERLY FLOW ALOFT IN ADVANCE OF THE
SHORTWAVE WILL RESULT IN 0-6 KM SHEAR ON THE ORDER OF 25-40 KT
(STRONGEST NORTH)...SUFFICIENT FOR ORGANIZED CONVECTION...ESPECIALLY
IN THE PRESENCE OF MODERATE INSTABILITY AND STEEP MID-LEVEL LAPSE
RATES.
SOME UNCERTAINTY PERSISTS WITH REGARD TO THE SPECIFICS OF THIS
SYSTEM GIVEN SMALL VARIANCES IN TIMING AND ONGOING CONVECTION /MCS
ACTIVITY/ EXPECTED TO TRACK INTO THE APPALACHIANS THU MORNING. GIVEN
EXCELLENT SYNOPTIC FORCING...MODERATE DESTABILIZATION AND FAVORABLE
DEEP-LAYER SHEAR...A SIGNIFICANT SEVERE WEATHER EPISODE IS EXPECTED
ACROSS THE REGION THU AFTERNOON AND EVENING. FROM A PATTERN
RECOGNITION STANDPOINT...THE EXPECTED ENVIRONMENT IN CENTRAL NC
WOULD PRIMARILY SUPPORT AN ENHANCED THREAT OF DAMAGING WINDS GIVEN
UNIDIRECTIONAL DEEP-LAYER SHEAR...SPEEDY MID-LEVEL FLOW AND STRONG
EVAP COOLING POTENTIAL ASSOC/W THE MODIFIED EML IN PLACE AND
INVERTED-V PROFILES IN THE BOUNDARY LAYER. W/REGARD TO CONVECTIVE
MODE...EXPECT A RELATIVELY NARROW WINDOW FOR ANY DISCRETE CONVECTION
PRIOR TO RAPID UPSCALE GROWTH INTO AN MCS GIVEN HIGH DCAPE /STRONG
COLD POOLS/ AND MODERATE INSTABILITY. THE LATEST GUIDANCE SUGGESTS
THAT THE TORNADO THREAT WOULD LIKELY REMAIN WELL TO THE NORTH (I.E.
NORTHERN VA/MD/PA/NJ) AND OTHER PORTIONS OF THE MID-ATLANTIC
COAST...IN CLOSER VICINITY TO THE SFC LOW TRACK AND WARM FRONT AND
BETTER LOW-LEVEL DIRECTIONAL SHEAR. WITH EXPECTED MCS ACTIVITY AND
OUTFLOW PROGRESSING INTO THE MOUNTAINS THU MORNING AND A POTENTIAL
FOR HINDERED DESTABILIZATION MID/LATE THU MORNING INTO EARLY THU
AFTERNOON IN THE FAR W/NW PIEDMONT...HAVE DECREASED PRECIP CHANCES
TO 40% IN THAT AREA...WITH PRECIP CHANCES AT 50% IN VICINITY OF THE
HWY 1 CORRIDOR AND 60-70% EAST OF INTERSTATE 95. EXPECT THE BEST
SEVERE THREAT EAST OF HWY 1 AT THIS TIME. HIGHS LOWER TO MID
90S...WARMEST EAST...THOUGH CONFIDENCE IS LOWER THAN NORMAL GIVEN
UNCERTAINTY W/REGARD TO MCS ACTIVITY/CLOUD COVER THAT MAY PROGRESS
INTO WESTERN PORTIONS OF THE STATE IN THE MORNING. EXPECT LOWS THU
NIGHT IN THE MID TO UPPER 60S IN THE WAKE OF A COLD FRONTAL PASSAGE
AS THE SHORTWAVE AND ATTENDANT SFC LOW TRACK OFFSHORE THE
MID-ATLANTIC. -VINCENT
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 240 PM WEDNESDAY...
CONDITIONS WILL DRY OUT AND COOL DOWN BEHIND THE DEPARTING SYSTEM
FOR THE END OF THE WORK WEEK AND EARLY WEEKEND. THE STRONG MID/UPPER
LEVEL TROUGH WILL BE CROSSING THE AREA DURING THE DAY ON FRIDAY AND
VERY WELL COULD PRODUCE A COUPLE OF SHOWERS OR SOME SPRINKLES.
HOWEVER...THE DEEP MOISTURE WILL HAVE MOVED OFFSHORE...SO AM NOT
EXPECTING ENOUGH COVERAGE TO PUT ANY MENTION IN THE FORECAST. IF
ANYTHING DOES DEVELOP...IT SHOULD BE ACROSS THE EASTERN THIRD OF THE
FORECAST AREA WHERE SOME RESIDUAL MOISTURE (PWAT VALUES NEAR AN
INCH) MAY RESIDE.
THEN...SURFACE HIGH PRESSURE AND RISING HEIGHTS ALOFT (ALTHOUGH THE
CORE OF THE MID/UPPER HIGH WILL REMAIN WEST OF OF THE REGION BEFORE
FLATTENING OUT BY THE LATTER HALF OF THE WEEKEND) WILL LEAD TO MORE
SUNSHINE AND MOSTLY DRY CONDITIONS THROUGH MUCH OF THE WEEKEND.
TEMPS SHOULD STAY BELOW NORMAL (HIGHS IN THE LOW/MID 80S...OVERNIGHT
LOWS IN THE LOW 60S...WITH EVEN SOME UPPER 50S POSSIBLE) FRIDAY AND
SATURDAY...BEFORE MODIFYING ON SUNDAY AS THE SURFACE HIGH SHIFTS
OFFSHORE. THE NEXT SYSTEM LOOKS TO APPROACH THE REGION EARLY NEXT
WEEK...BUT THERE ARE STILL SOME TIMING/STRENGTH ISSUES BETWEEN THE
MODELS. AT THIS TIME...IT APPEARS A FRONT WILL MOVE THROUGH THE AREA
SOMETIME ON TUESDAY...WHICH IS WHEN THE BEST CHANCE OF RAIN WILL BE
FOCUSED. HOWEVER...INCREASING SOUTHWESTERLY FLOW WILL DRIVE OUR
MOISTURE BACK UP AND THEREFORE WILL HAVE SLIGHT CHANCE POPS FOR
MONDAY. TEMPS WILL BE NEAR NORMAL FOR THE BEGINNING ON NEXT WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 140 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE CURRENT TAF
PERIOD. THERE COULD BE AN ISOLATED SHOWER OR THUNDERSTORM THAT
DEVELOPS LATER THIS AFTERNOON...MOST LIKELY ACROSS THE WEST...BUT
CHANCES ARE TOO SMALL TO INCLUDE ANY MENTION IN THE TAFS.
OTHERWISE...SOUTHWESTERLY WINDS WILL INCREASE THURSDAY MORNING...
WITH GUSTS AROUND 25 KNOTS POSSIBLE. IT STILL APPEARS THAT THE
MAJORITY OF THE PRECIP WILL HOLD OFF UNTIL AFTER 18Z THURSDAY.
OUTLOOK...ADVERSE AVIATION CONDITIONS IN THE FORM OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE DAY
THURSDAY...LIKELY BEGINNING SHORTLY AFTER 18Z. ANY THUNDERSTORMS
THAT DEVELOP WILL BE CAPABLE OF PRODUCING DAMAGING SURFACE WIND
GUSTS IN EXCESS OF 50 KNOTS. AT THIS TIME...THE BEST CHANCE FOR
AFTERNOON CONVECTION AND SEVERE WEATHER WILL BE AT THE RDU/FAY/RWI
TERMINALS. GUSTY SOUTHWESTERLY WINDS (SEE ABOVE PARAGRAPH) WILL
SHIFT TO THE NORTHWEST IN THE WAKE OF A COLD FRONTAL PASSAGE
THURSDAY EVENING/NIGHT. EXPECT DRY/VFR CONDITIONS TO PREVAIL IN THE
WAKE OF THE FRONT FRIDAY THROUGH THE WEEKEND...WITH THE NEXT CHANCE
OF PRECIP RETURNING TO THE AREA EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...BLAES/VINCENT
SHORT TERM...VINCENT
LONG TERM...KRR
AVIATION...KRR/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
143 PM EDT WED JUN 12 2013
.SYNOPSIS...
A DEEPENING LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL
PROGRESS FROM THE CENTRAL PLAINS INTO THE OHIO VALLEY TONIGHT...THEN
TRACK EAST THROUGH THE MID ATLANTIC AND CAROLINAS ON THURSDAY. DRY
HIGH PRESSURE WILL BUILD INTO THE REGION IN THE WAKE OF THE COLD
FRONT THURSDAY NIGHT AND FRIDAY.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 1100 AM WEDNESDAY...
AN UPPER LEVEL RIDGE CENTERED OVER THE SOUTHERN PLAINS WILL
STRENGTHEN SOMEWHAT TODAY WITH MINOR HEIGHT RISES ACROSS THE MID
ATLANTIC. SMALL AMPLITUDE DISTURBANCES IN NW FLOW ALOFT ARE
EXPECTED TO TRACK SOUTHEAST INTO THE CAROLINAS THIS AFTERNOON
THROUGH TONIGHT WHILE A MUCH MORE POTENT SHORTWAVE CENTERED ATOP THE
RIDGE IN THE NORTHERN PLAINS THIS MORNING WILL TRACK INTO THE TN/OH
VALLEY TONIGHT. A WEAK SURFACE TROUGH ACROSS CENTRAL NC WILL PERSIST
ACROSS WESTERN/CENTRAL NC WITH A LIGHT SW SURFACE WIND BECOMING MORE
WESTERLY THIS AFTERNOON.
WE HAVE BEEN MONITORING A REGION OF ISOLATED CONVECTION IN THE
CENTRAL APPALACHIANS THAT DEVELOPED OVERNIGHT. THE FACT THIS
DEVELOPED DURING AN ATYPICAL TIME OF DAY SUGGEST THAT SOME MESOSCALE
FORCING IS LIKELY DRIVING THIS AND IT APPEARS TO BE DEVELOPING IN A
REGION OF WARM ADVECTION AND ENHANCED MID LEVEL FLOW. CONVECTION
ALLOWING MODELS PROVIDE A VARIETY OF SOLUTIONS WITH THIS CONVECTION:
THE 00 UTC ARW/NMM HI RES WINDOWS SUGGEST SOME OF THE CONVECTION
WILL PERSIST AND GROW INTO A CLUSTER OF CONVECTION AROUND MIDDAY AND
SWEEP SOUTHEAST ACROSS THE PIEDMONT WHILE THE HRRR SUGGESTS THAT
ONGOING CONVECTION WILL WEAKEN WITH LITTLE ADDITIONAL REDEVELOPMENT
LIKELY. WITH RECENT RADAR TRENDS SUGGESTING A DECREASE IN
INTENSITY/COVERAGE OF THE CONVECTION AND THE PERSISTENCE OF A MID
LEVEL CAPPING INVERSION...HAVE OPTED TO REMOVE SLIGHT CHANCE POPS IN
THE EAST THIS AFTERNOON AND HIGHLIGHT THE FAR WEST DURING THE EARLY
TO MID AFTERNOON PERIOD FOR SLIGHT CHC POPS...ESPECIALLY ALONG THE
YADKIN RIVER.
CONVECTIVE DEBRIS CLOUDS ARE ALREADY SPREADING ACROSS THE WESTERN
PIEDMONT AND WILL SWEEP INTO THE EASTERN PIEDMONT AND SANDHILLS THIS
AFTERNOON. THE THICKER CLOUDS CLOSE TO THE YADKIN SHOULD BE
SUFFICIENT ENOUGH TO RETARD TEMPERATURES A DEGREE OR TWO. BUT WE
STILL EXPECT HIGHS TO RANGE IN THE 88 TO 95 RANGE TODAY. EXPECT LOWS
OVERNIGHT IN THE 69 TO 73 RANGE. -BLAES/VINCENT
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 AM WEDNESDAY...
...SEVERE WEATHER EXPECTED THURSDAY AFTERNOON AND EVENING...
THURSDAY AND THURSDAY NIGHT:
AN UNSEASONABLY AMPLIFIED PATTERN WILL PERSIST ON THU...
CHARACTERIZED BY A STRONG UPPER LEVEL RIDGE OVER THE CENTRAL CONUS
AND NW FLOW ALOFT DOWNSTREAM ACROSS THE TN/OH VALLEY AND
MID-ATLANTIC. ROBUST SHORTWAVE ENERGY (AND AN ATTENDANT SFC LOW) IN
THE OH VALLEY THU MORNING WILL TRACK EAST ACROSS THE MID-ATLANTIC
THU AFTERNOON AND EVENING. MODERATE INSTABILITY (1500-2500 J/KG
MLCAPE) IS EXPECTED ACROSS CENTRAL NC...IN ASSOCIATION WITH STEEP
(6.5-7.5 C/KM) MID-LEVEL LAPSE RATES AND SEASONABLE BOUNDARY LAYER
MOISTURE. STRENGTHENING WESTERLY FLOW ALOFT IN ADVANCE OF THE
SHORTWAVE WILL RESULT IN 0-6 KM SHEAR ON THE ORDER OF 25-40 KT
(STRONGEST NORTH)...SUFFICIENT FOR ORGANIZED CONVECTION...ESPECIALLY
IN THE PRESENCE OF MODERATE INSTABILITY AND STEEP MID-LEVEL LAPSE
RATES.
SOME UNCERTAINTY PERSISTS WITH REGARD TO THE SPECIFICS OF THIS
SYSTEM GIVEN SMALL VARIANCES IN TIMING AND ONGOING CONVECTION /MCS
ACTIVITY/ EXPECTED TO TRACK INTO THE APPALACHIANS THU MORNING. GIVEN
EXCELLENT SYNOPTIC FORCING...MODERATE DESTABILIZATION AND FAVORABLE
DEEP-LAYER SHEAR...A SIGNIFICANT SEVERE WEATHER EPISODE IS EXPECTED
ACROSS THE REGION THU AFTERNOON AND EVENING. FROM A PATTERN
RECOGNITION STANDPOINT...THE EXPECTED ENVIRONMENT IN CENTRAL NC
WOULD PRIMARILY SUPPORT AN ENHANCED THREAT OF DAMAGING WINDS GIVEN
UNIDIRECTIONAL DEEP-LAYER SHEAR...SPEEDY MID-LEVEL FLOW AND STRONG
EVAP COOLING POTENTIAL ASSOC/W THE MODIFIED EML IN PLACE AND
INVERTED-V PROFILES IN THE BOUNDARY LAYER. W/REGARD TO CONVECTIVE
MODE...EXPECT A RELATIVELY NARROW WINDOW FOR ANY DISCRETE CONVECTION
PRIOR TO RAPID UPSCALE GROWTH INTO AN MCS GIVEN HIGH DCAPE /STRONG
COLD POOLS/ AND MODERATE INSTABILITY. THE LATEST GUIDANCE SUGGESTS
THAT THE TORNADO THREAT WOULD LIKELY REMAIN WELL TO THE NORTH (I.E.
NORTHERN VA/MD/PA/NJ) AND OTHER PORTIONS OF THE MID-ATLANTIC
COAST...IN CLOSER VICINITY TO THE SFC LOW TRACK AND WARM FRONT AND
BETTER LOW-LEVEL DIRECTIONAL SHEAR. WITH EXPECTED MCS ACTIVITY AND
OUTFLOW PROGRESSING INTO THE MOUNTAINS THU MORNING AND A POTENTIAL
FOR HINDERED DESTABILIZATION MID/LATE THU MORNING INTO EARLY THU
AFTERNOON IN THE FAR W/NW PIEDMONT...HAVE DECREASED PRECIP CHANCES
TO 40% IN THAT AREA...WITH PRECIP CHANCES AT 50% IN VICINITY OF THE
HWY 1 CORRIDOR AND 60-70% EAST OF INTERSTATE 95. EXPECT THE BEST
SEVERE THREAT EAST OF HWY 1 AT THIS TIME. HIGHS LOWER TO MID
90S...WARMEST EAST...THOUGH CONFIDENCE IS LOWER THAN NORMAL GIVEN
UNCERTAINTY W/REGARD TO MCS ACTIVITY/CLOUD COVER THAT MAY PROGRESS
INTO WESTERN PORTIONS OF THE STATE IN THE MORNING. EXPECT LOWS THU
NIGHT IN THE MID TO UPPER 60S IN THE WAKE OF A COLD FRONTAL PASSAGE
AS THE SHORTWAVE AND ATTENDANT SFC LOW TRACK OFFSHORE THE
MID-ATLANTIC. -VINCENT
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
FRIDAY AND FRIDAY NIGHT...THE LONGWAVE TROUGH MOVES EAST
FRIDAY...WITH AMPLE NVA IN THE MID-LEVELS TAKING PLACE FRIDAY NIGHT.
THE MEAN AIR MASS IS DRY...WITH A SLIGHT INCREASE IN OVERALL
MOISTURE TOWARD THE NORTHEAST PART OF THE STATE...INCLUDING THE
NORTHERN COASTAL PLAIN...CLOSER TO THE DEPARTING MID-LEVEL LOW. THE
GFS FORECASTS LINGERING...HIGHER PRECIPITABLE WATER VALUES NEAR AN
INCH TOWARD KIXA FRIDAY AFTERNOON...ALTHOUGH GFS BUFR SOUNDINGS AS
WELL AS NAM BUFR SOUNDINGS ARE STABLE AND CAPPED AROUND 700MB.
INTERESTINGLY BUT NOT TERRIBLY SURPRISING GIVEN THE STRENGTH OF THE
DEPARTING UPPER LOW...THE NAM AND GFS PRODUCE MEAGER...JUST
NOTICEABLE QPF MAINLY JUST EAST OF CENTRAL NORTH CAROLINA OVER THE
NORTHEAST PART OF THE STATE DURING FRIDAY AFTERNOON. SIMILAR
SCENARIOS HAVE OCCURRED IN THE RECENT PAST...BEHIND STRONG MID-LEVEL
SYSTEMS WHERE ENOUGH MOISTURE LINGERS TO RESULT IN ISOLATED SHOWERS
OR SPRINKLES SKIRTING OR MOVING INTO CENTRAL NORTH CAROLINA FROM THE
NORTHEAST. ON FRIDAY...WHILE A SPRINKLE MAY OCCUR LATE IN THE DAY
TOWARD KIXA...THE GFS FORECAST COMBINATION OF BEST 850MB AND 700MB
MOISTURE RESIDES JUST EAST OF CENTRAL NORTH CAROLINA BETWEEN 18Z
FRIDAY AND 00Z SATURDAY. AS A RESULT...WILL KEEP THIS FORECAST
DRY...SHOWING A RELATIVELY HIGHER AMOUNT OF CLOUDS IN THE AREA
DURING THE AFTERNOON THROUGH THE EVENING MAINLY FROM WILSON NORTH.
1000-850MB THICKNESSES AND BIAS CORRECTED TEMPERATURE GUIDANCE ALL
FAVOR HIGHS NEAR THE COOLER MET GUIDANCE FOR FRIDAY...AND BUFR
SOUNDINGS SHOW THERE MAY BE ENOUGH HIGH-BASED CU/SC FOR HIGHS TO BE
TEMPERED SOMEWHAT FROM THE WARMER MAV VALUES. OVERNIGHT LOWS 57 TO
62. EXPECT A FEW WIND GUSTS IN THE UPPER TEENS TO POSSIBLY LOWER 20S
KNOTS FRIDAY WITH INITIAL MIXING IN THE TIGHT GRADIENT BEHIND THE
DEPARTING LOW.
FOR THE PERIOD SATURDAY THROUGH TUESDAY...THE FORECAST FOR SATURDAY
REMAINS DRY AS A STABLE AND DRY AIR MASS UNDER HIGH PRESSURE IS
ANTICIPATED. AS THE WEEKEND ENDS AND WE APPROACH THE BEGINNING OF
THE NEXT WORK WEEK...GUIDANCE IS CONSISTENT IN PUSHING MODESTLY
STRONG MID-LEVEL SHORTWAVES ATOP THE RIDGE TO OUR WEST...EVENTUALLY
FLATTENING THAT UPPER RIDGE. THE CENTER OF SURFACE HIGH PRESSURE
MOVES OFF TO THE EAST OF CENTRAL NORTH CAROLINA BY SUNDAY
AFTERNOON...BRINGING MORE MOISTURE INTO CENTRAL NORTH CAROLINA.
BASED ON THE CONSENSUS OF THE LATEST GFS AND THE 12Z ECMWF...THE
APPROACH OF THE NEXT SURFACE FRONT WILL BE AT LEAST LATE TUESDAY...
WITH THE TYPICAL PIEDMONT TROUGH IN PLACE FOR SUNDAY INTO MONDAY.
WHILE THERE IS A NOTICEABLE INCREASE IN 850MB THETA-E AIR SUNDAY AS
PRECIPITABLE WATER VALUES RISE FROM UNDER AN INCH SATURDAY TO CLOSE
TO 1.5 INCHES ON THE GFS...AND THERE IS A SLIGHT STEEPENING OF THE
MID-LEVEL LAPSE RATES...GFS BUFR SOUNDINGS ARE STILL CAPPED TO DEEP
CONVECTION SUNDAY AFTERNOON. THERE IS A LITTLE CONCERN ABOUT
UPSTREAM DEVELOPMENT MOVING INTO THE REGION...BUT THE GFS THICKNESS
PROFILE WOULD SUGGEST ANY SUCH DEVELOPMENT WOULD TEND TO TRACK WELL
NORTH AND NORTHEAST OF THE AREA. IF ANYTHING DEVELOPS AT ALL
SUNDAY...IT IS CURRENTLY EXPECTED TO BE VERY ISOLATED. AS HEIGHTS
ALOFT CONTINUE TO FALL...AND LAPSE RATES AT LEAST ON THE GFS STEEPEN
EVER SO SLIGHTLY MONDAY COMPARED TO SUNDAY AS MOISTURE CONTINUES TO
INCREASE...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ARE POSSIBLE.
THE GFS BUFR SOUNDINGS ARE STILL WEAKLY CAPPED MONDAY AROUND 750MB...
AND THE COARSE 12Z ECMWF SOUNDINGS ACTUALLY ARE MORE STABLE MONDAY
THAN SUNDAY...SO WILL KEEP CHANCES FOR PRECIPITATION SLIGHT AT THIS
TIME...AND LOWEST IN THAT RANGE OVER THE SANDHILLS AND SOUTHERN
COASTAL PLAIN. BY TUESDAY...WITH THE SLOW APPROACH OF THE FRONT...
AND A CONTINUED INCREASE IN MOISTURE AND COOLING ALOFT...AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED. OVERNIGHT LOWS
WILL GRADUALLY RISE FROM THE LOWER TO MID 60S SATURDAY NIGHT TO 69
TO 74 BY MONDAY NIGHT. AFTER HIGHS SATURDAY CLOSE TO 1000-850MB
THICKNESSES IN THE LOWER TO MID 80S...FORECAST HIGHS WILL BE IN THE
MID 80S TO AROUND 90...WARMEST MONDAY WITH THIS FORECAST. ONE
POSSIBLE ALTERNATIVE IS THAT SUNDAY ACTUALLY ENDS UP WARMER THAN
MONDAY WHEN THE AIR IS A LITTLE DRIER AS THE SOUTHWEST SURFACE
FLOW INITIALLY BECOMES MORE ENTRENCHED. FOR THAT DAY...LEANED ON THE
HIGH SIDE OF THE AVAILABLE GUIDANCE SUITE. -DJF
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 140 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE CURRENT TAF
PERIOD. THERE COULD BE AN ISOLATED SHOWER OR THUNDERSTORM THAT
DEVELOPS LATER THIS AFTERNOON...MOST LIKELY ACROSS THE WEST...BUT
CHANCES ARE TOO SMALL TO INCLUDE ANY MENTION IN THE TAFS.
OTHERWISE...SOUTHWESTERLY WINDS WILL INCREASE THURSDAY MORNING...
WITH GUSTS AROUND 25 KNOTS POSSIBLE. IT STILL APPEARS THAT THE
MAJORITY OF THE PRECIP WILL HOLD OFF UNTIL AFTER 18Z THURSDAY.
OUTLOOK...ADVERSE AVIATION CONDITIONS IN THE FORM OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE DAY
THURSDAY...LIKELY BEGINNING SHORTLY AFTER 18Z. ANY THUNDERSTORMS
THAT DEVELOP WILL BE CAPABLE OF PRODUCING DAMAGING SURFACE WIND
GUSTS IN EXCESS OF 50 KNOTS. AT THIS TIME...THE BEST CHANCE FOR
AFTERNOON CONVECTION AND SEVERE WEATHER WILL BE AT THE RDU/FAY/RWI
TERMINALS. GUSTY SOUTHWESTERLY WINDS (SEE ABOVE PARAGRAPH) WILL
SHIFT TO THE NORTHWEST IN THE WAKE OF A COLD FRONTAL PASSAGE
THURSDAY EVENING/NIGHT. EXPECT DRY/VFR CONDITIONS TO PREVAIL IN THE
WAKE OF THE FRONT FRIDAY THROUGH THE WEEKEND...WITH THE NEXT CHANCE
OF PRECIP RETURNING TO THE AREA EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...BLAES/VINCENT
SHORT TERM...VINCENT
LONG TERM...DJF
AVIATION...KRR/VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
122 PM EDT WED JUN 12 2013
.SYNOPSIS...
HOT TEMPERATURES ARE EXPECTED TODAY AND THURSDAY AS AN UPPER RIDGE
MOVES ACROSS THE REGION. A FEW THUNDERSTORMS MAY DEVELOP INLAND
LATE IN THE AFTERNOON. A RELATIVELY STRONG COLD FRONT WILL MOVE
ACROSS THE AREA THURSDAY NIGHT WITH A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS. DRY WEATHER IS EXPECTED INTO THE WEEKEND. A COLD
FRONT WILL REACH THE CAROLINAS EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM WEDNESDAY...HOT AND HUMID DAY ON TAP FOR THE AREA AS
SUMMER MAKES ITS FIRST STRONG FORAY INTO THE CAROLINAS. WV IMAGERY
THIS MORNING PAINTS THE PICTURE WITH LARGE SURFACE HIGH AND MID
LEVEL RIDGING ELONGATED WEST-TO-EAST ACROSS THE SOUTHERN TIER AND
OUT INTO THE ATLANTIC OCEAN. THIS IS A MODIFIED "RING OF FIRE"
SETUP...AND STRONG CONVECTION IS ANTICIPATED ACROSS THE OH VLY INTO
THE MID-ATLANTIC TODAY. THE BIG QUESTIONS FOR TODAY WILL BE: 1) HOW
HOT WILL IT GET AND 2) WILL THERE BE CONVECTION THIS EVENING.
AS FAR AS TEMPERATURES GO...AM EXPECTING THE HOTTEST DAY SINCE
SEPTEMBER 1, 2012. 12Z SOUNDING AT KCHS SHOWED 850MB TEMPS OF
20C...WHILE KMHX HAD 15C. THIS SHOWS THE LEVEL OF WARMTH POSSIBLE
TODAY...AS MID-LEVEL THERMAL RIDGE WILL BULGE NORTHWARD TODAY...AND
NAM BUFR SOUNDINGS SHOW 3-4C OF WARMING AT 850MB THROUGH TONIGHT.
THESE VERY WARM TEMPS COMBINED WITH AMPLE SOLAR INSOLATION AND SOME
DOWNSLOPE WARMING THANKS TO NW FLOW ABOVE 900MB...WILL ALLOW TEMPS
TO SOAR WELL INTO THE 90S TODAY. HAVE SIDED WITH THE HIGHER MAV
NUMBERS...WHICH SUGGESTS TEMPS RISING TO 92-97 TODAY...WITH UPPER
80S EVEN AT THE IMMEDIATE BEACHES. THESE TEMPS COMBINED WITH
DEWPOINTS IN THE UPPER 60S...LOW 70S AT THE COAST...WILL DRIVE HEAT
INDICIES TO AROUND 100 DEGREES...AND A HEAT RELATED SPS REMAINS IN
EFFECT FOR TODAY.
FOR CONVECTION...THE SITUATION IS QUITE TRICKY. HIGH-RES GUIDANCE IS
SHOWING MANY DIFFERENT SOLUTIONS...BUT THERE ARE REALLY TWO CAMPS.
THE NAM/ARW/NMM SUGGESTS REMNANT MCS CONVECTION RIDING DOWN TO THE
SOUTH AND CLIPPING THE WESTERN PORTIONS OF THE CWA. THE
HRRR/WRF/SREF ARE MUCH LESS AGGRESSIVE...WITH THE HRRR SHOWING NO
DEVELOPMENT AT ALL. SO...WHICH SOLUTION WILL BE RIGHT? WHILE A FEW
STORMS HAVE ALREADY FIRED ACROSS THE MTNS OF VA/WV...THIS COULD BE
AN INDICATOR THAT MORE DEVELOPMENT WILL OCCUR THIS AFTN IN A
WELL-HEATED ENVIRONMENT. IF THIS OCCURS...IT WOULD TEND TO RIDE
SOUTH AROUND THE RIDGE TOWARDS THE WESTERN CWA. AT THE SAME TIME
HOWEVER...MID LEVEL RIDGING AND THERMAL ADVECTION WILL WORK AGAINST
THIS...AS SUBSIDENCE AND WEAKENING MID-LEVEL LAPSE RATES SQUELCH
ADVANCING CONVECTION. HAVE CONTINUED SCHC FOR THE WESTERN HALF OF
THE CWA...BUT IT WILL LIKELY BE A DAY WHERE UPDATES NEED TO BE MADE
IN A NOWCAST MANNER AS CONVECTION TRENDS BECOME DETERMINED.
MINS TONIGHT WILL REMAIN WELL ABOVE NORMAL WITH CONTINUED SW WINDS
AND WAA...FALLING ONLY INTO THE MID 70S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...THE HOTTEST DAY OF THE YEAR SO FAR
EXPECTED ON THURSDAY. TEMPS WILL SOAR INTO THE MID 90S AS STRONG
WESTERLY DOWNSLOPE FLOW DEVELOPS THROUGH THE LOW LEVELS OF THE
ATMOSPHERE AND RIDGE EXTENDS INTO THE CAROLINAS THROUGH THE MID
TO UPPER LEVELS. MODELS SHOW W WINDS UP TO 30 TO 40 KT JUST ABOVE
THE SURFACE WITH H5 HEIGHTS UP TO 589 DEM. AT THE SAME TIME DEW
POINT TEMPS WILL REMAIN AROUND 70 DEGREES. TEMPS LOOKS LIKE THEY
WILL BE WARMEST ACROSS INLAND AREAS WITH PEAK ACROSS NORTHEAST
SOUTH CAROLINA. THE DEWPOINT TEMPS WILL BE HIGHEST THROUGH THE
MORNING HOURS BUT ONCE MIXING OCCURS READINGS WILL DROP INTO THE
60S INLAND WITH GREATEST VALUES ACROSS GEORGETOWN AND HORRY
COUNTIES IN THE AFTERNOON. THESE TWO COUNTIES WILL MOST LIKELY
SURPASS HEAT ADVISORY CRITERIA WITH APPARENT TEMPERATURES UP ABOVE
105 F...WHILE THE REST OF SOUTH CAROLINA ZONES WILL BE CLOSE.
SOUTHEAST NORTH CAROLINA WILL FEEL CLOSER TO 100 DEGREES F.
AFTER SUCH A WARM AND DRY DAY ON THURSDAY...A COLD FRONT WILL
APPROACH FROM THE NORTHWEST. IT LOOKS LIKE THE BEST DYNAMICS WILL
COME TOGETHER IN THE EVENING HOURS AS A SHORTWAVE PUSHES THE FRONT
EAST ACROSS THE AREA. THE BEST SHORTWAVE ENERGY WILL REMAIN TO OUR
NORTH BUT STILL IMPRESSIVE LIFT AND MOISTURE OVER LOCAL AREA TO
PRODUCE POTENTIAL FOR SEVERE THUNDERSTORMS. CAPE VALUES UP TO 2-3K
J/KG WITH STEEP MID LEVEL LAPSE RATES WILL SUPPORT POTENTIAL FOR
STRONG TO SEVERE STORMS. THE STRONG STEERING FLOW WILL DRIVE
THESE STORMS RAPIDLY THROUGH THE AREA AND OFF THE COAST THROUGH
THE EVENING. THE ONE INHIBITING FACTOR WILL BE THE LOSS OF SURFACE
HEATING ALTHOUGH WITH TEMPS WELL INTO THE 90S IN THE
AFTN...READINGS WILL STILL BE HIGH THROUGH THE EVENING HOURS. ONE
OTHER LIMITING FACTOR WILL BE THE LACK OF GREAT MOISTURE RETURN
FROM THE GULF. THEREFORE EXPECT MOST ACTIVITY TO BE FOCUSED ALONG
AND JUST AHEAD OF FRONTAL BOUNDARY MOVING THROUGH RAPIDLY THROUGH
LATE EVENING. AFTER MIDNIGHT MOST OF THE ACTIVITY WILL MAINLY BE
CONFINED TO COASTAL COUNTIES OR OFF SHORE AS COLD FRONT MOVES
THROUGH. RAPID DRYING WILL FOLLOW WITH PCP WATER VALUES DROPPING
FROM 1.9 INCHES JUST AHEAD AND ALONG COLD FRONT DOWN TO LESS THAN
AN INCH BY DAYBREAK FRIDAY.
DEEP DRY NORTHERLY FLOW WILL KEEP TEMPS IN THE MID 80S FOR HIGHS
ON FRIDAY. THIS COMBINED WITH DEWPOINT TEMPS DOWN A GOOD 10
DEGREES WILL MAKE IT FEEL RELATIVELY COOLER ON FRIDAY. MAY SEE
SOME CU BUILD UP WITH RESIDUAL MOISTURE FROM RAINFALL THE NIGHT
BEFORE BUT OVERALL WILL SEE PLENTY OF SUNSHINE. WINDS WILL WEAKEN
THROUGH THE DAY ON FRI AS HIGH PRESSURE MOVES INTO THE CAROLINAS.
EXPECT DECENT RADIATIONAL COOLING FRI NIGHT WITH TEMPS COOLING
DOWN INTO THE MID 60S.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...HIGH PRESSURE WILL BUILD DOWN OVER THE
CAROLINAS AS MID TO UPPER RIDGE MOVES IN FROM THE WEST. A LIGHT
NORTHERLY FLOW ON FRONT END OF HIGH WILL LIGHTEN AND BECOME MORE
VARIABLE ON SATURDAY AS THE CENTER SHIFTS CLOSER OVERHEAD. A LIGHT
RETURN FLOW WILL SET UP SAT NIGHT INTO SUNDAY AS THE HIGH SHIFTS
OFF SHORE. OVERALL EXPECT SEASONABLE WEATHER WITH PLENTY OF
SUNSHINE AND TEMPS RIGHT AROUND NORMAL...IN THE MID 80S DURING THE
DAY AND MID 60S OVERNIGHT. SFC DEWPOINTS INITIALLY WILL BE LOWER
BUT WILL CREEP UP BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK
PRODUCING SLIGHTLY MORE HUMID WEATHER. PCP WATER VALUES WILL
REMAIN CLOSER TO AN INCH THROUGH THE WEEKEND INTO EARLY NEXT WEEK.
BY LATE MONDAY INTO TUESDAY THE RIDGE ALOFT BEGINS TO BREAK DOWN
AS A SHORTWAVE DIGS DOWN FROM THE GREAT LAKES AND PUSHES A COLD
FRONT EAST BY TUESDAY. DEEPER LAYER MOISTURE WILL SET UP AHEAD OF
THE FRONT WITH PCP WATER VALUES INCREASING UP TO 1.75 INCHES IN A
DEEP SOUTHWESTERLY FLOW. EXPECT MORE ACTIVE WEATHER BY TUES
AFTERNOON AS COLD FRONT APPROACHES. RETURN FLOW NEXT WEEK WILL
LEAD TO TEMPS INCREASING A FEW DEGREES ABOVE CLIMO MON AND TUE.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...MODELS ARE NOT IN GOOD AGREEMENT WITH REGARDS TO
CONVECTION THIS AFTERNOON. THE HRRR HAS ABSOLUTELY NOTHING...WHILE
THE WRF AS SCATTERED CONVECTION OVER ABOUT A THIRD OF THE CWA. THINK
THERE WILL BE ISOLATED CB`S...BUT NOT ENOUGH COVERAGE FOR A VCTS
MENTION. SOUTHWEST FLOW WILL BE MORE SOUTH SOUTHWEST AND STRONGER AT
THE COASTAL TERMINALS DUE TO THE RESULTANT. LIGHT WINDS TONIGHT WITH
A REASONABLE CHANCE FOR A COUPLE OF HOURS OF FOG AFTER 09Z.
THURSDAY...CONTINUED SOUTHWEST FLOW WITH MAINLY SCATTERED HIGH
CLOUDS. ANY CONVECTION WILL HOLD OFF UNTIL THE END OF THE FORECAST
VALID PERIOD.
EXTENDED OUTLOOK...ISOLATED SHOWERS/THUNDERSTORMS WITH TEMPO PERIODS
OF MVFR/IFR POSSIBLE THURSDAY EVENING INTO FRIDAY MORNING. MORNING
FOG POSSIBLE SUNDAY AND MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM WEDNESDAY...CONTINUED SW WINDS AROUND OFFSHORE HIGH
PRESSURE WILL KEEP SW WINDS AND A SW WIND CHOP PREDOMINANT OVER THE
WATERS. SEAS CURRENTLY 2-4 FT WILL REMAIN STATUS QUO THROUGH THE
PERIOD...WITH SW WINDS OF 10-15 KTS PERSISTENT. THE EXCEPTION TO
THIS WILL BE WITHIN THE INNER FEW NM IN THE SEA BREEZE
BOUNDARY...WITH A SLIGHTLY BACKING TO SOUTH WILL OCCUR AS WELL AS AN
INCREASE IN SPEEDS...WITH GUSTS UP TO 20 KTS. SEAS WILL REMAIN 2-4
FT IN THIS ZONE...BUT WILL BECOME MORE CHOPPY THANKS TO SHORTER
PERIODS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...WINDS WILL INCREASE OUT OF THE SW THROUGH
THURSDAY AS COLD FRONT APPROACHES FROM THE WEST. WINDS WILL START
OUT AROUND 15 KTS BUT WILL REACH UP TO 20 TO 25 KTS THURS EVENING
JUST AHEAD OF THE COLD FRONT. THESE WINDS WILL HELP DRIVE SEAS UP
FROM 2 TO 4 FT EARLY THURS UP TO 4 TO 6 FT THURS EVENING REACHING
SMALL CRAFT CRITERIA LATE THURS AFTN INTO THURSDAY EVENING.
ONCE COLD FRONT CROSSES THE WATERS AFTER MIDNIGHT THURS NIGHT INTO
EARLY FRIDAY...THE WINDS WILL VEER AROUND TO THE NORTHWEST. SEAS
WILL DROP DOWN BELOW SCA QUICKLY OVERNIGHT AND WILL CONTINUE TO
SUBSIDE IN A WEAKENING OFF SHORE FLOW THROUGH FRIDAY. SEAS WILL BE
2 TO 3 FT MOST WATERS BY FRI EVENING.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...
HIGH PRESSURE WILL SHIFT CLOSER OVERHEAD ON SATURDAY AND THEN WILL
SHIFT FURTHER OFF THE COAST BY SATURDAY NIGHT INTO SUNDAY.
THEREFORE WINDS WILL VEER AROUND FROM NORTHERLY ON SATURDAY TO
SOUTHERLY BY SUNDAY REMAINING AROUND 10 KT OR LESS. WINDS WILL
SPIKE UP IN SEA BREEZE EACH AFTERNOON IN NEAR SHORE WATERS. SEAS
WILL REMAIN 3 FT OR LESS THROUGH MUCH OF THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...43/17
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1111 AM EDT WED JUN 12 2013
.SYNOPSIS...
HOT TEMPERATURES ARE EXPECTED TODAY AND THURSDAY AS AN UPPER RIDGE
MOVES ACROSS THE REGION. A FEW THUNDERSTORMS MAY DEVELOP INLAND
LATE IN THE AFTERNOON. A RELATIVELY STRONG COLD FRONT WILL MOVE
ACROSS THE AREA THURSDAY NIGHT WITH A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS. DRY WEATHER IS EXPECTED INTO THE WEEKEND. A COLD
FRONT WILL REACH THE CAROLINAS EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM WEDNESDAY...HOT AND HUMID DAY ON TAP FOR THE AREA AS
SUMMER MAKES ITS FIRST STRONG FORAY INTO THE CAROLINAS. WV IMAGERY
THIS MORNING PAINTS THE PICTURE WITH LARGE SURFACE HIGH AND MID
LEVEL RIDGING ELONGATED WEST-TO-EAST ACROSS THE SOUTHERN TIER AND
OUT INTO THE ATLANTIC OCEAN. THIS IS A MODIFIED "RING OF FIRE"
SETUP...AND STRONG CONVECTION IS ANTICIPATED ACROSS THE OH VLY INTO
THE MID-ATLANTIC TODAY. THE BIG QUESTIONS FOR TODAY WILL BE: 1) HOW
HOT WILL IT GET AND 2) WILL THERE BE CONVECTION THIS EVENING.
AS FAR AS TEMPERATURES GO...AM EXPECTING THE HOTTEST DAY SINCE
SEPTEMBER 1, 2012. 12Z SOUNDING AT KCHS SHOWED 850MB TEMPS OF
20C...WHILE KMHX HAD 15C. THIS SHOWS THE LEVEL OF WARMTH POSSIBLE
TODAY...AS MID-LEVEL THERMAL RIDGE WILL BULGE NORTHWARD TODAY...AND
NAM BUFR SOUNDINGS SHOW 3-4C OF WARMING AT 850MB THROUGH TONIGHT.
THESE VERY WARM TEMPS COMBINED WITH AMPLE SOLAR INSOLATION AND SOME
DOWNSLOPE WARMING THANKS TO NW FLOW ABOVE 900MB...WILL ALLOW TEMPS
TO SOAR WELL INTO THE 90S TODAY. HAVE SIDED WITH THE HIGHER MAV
NUMBERS...WHICH SUGGESTS TEMPS RISING TO 92-97 TODAY...WITH UPPER
80S EVEN AT THE IMMEDIATE BEACHES. THESE TEMPS COMBINED WITH
DEWPOINTS IN THE UPPER 60S...LOW 70S AT THE COAST...WILL DRIVE HEAT
INDICIES TO AROUND 100 DEGREES...AND A HEAT RELATED SPS REMAINS IN
EFFECT FOR TODAY.
FOR CONVECTION...THE SITUATION IS QUITE TRICKY. HIGH-RES GUIDANCE IS
SHOWING MANY DIFFERENT SOLUTIONS...BUT THERE ARE REALLY TWO CAMPS.
THE NAM/ARW/NMM SUGGESTS REMNANT MCS CONVECTION RIDING DOWN TO THE
SOUTH AND CLIPPING THE WESTERN PORTIONS OF THE CWA. THE
HRRR/WRF/SREF ARE MUCH LESS AGGRESSIVE...WITH THE HRRR SHOWING NO
DEVELOPMENT AT ALL. SO...WHICH SOLUTION WILL BE RIGHT? WHILE A FEW
STORMS HAVE ALREADY FIRED ACROSS THE MTNS OF VA/WV...THIS COULD BE
AN INDICATOR THAT MORE DEVELOPMENT WILL OCCUR THIS AFTN IN A
WELL-HEATED ENVIRONMENT. IF THIS OCCURS...IT WOULD TEND TO RIDE
SOUTH AROUND THE RIDGE TOWARDS THE WESTERN CWA. AT THE SAME TIME
HOWEVER...MID LEVEL RIDGING AND THERMAL ADVECTION WILL WORK AGAINST
THIS...AS SUBSIDENCE AND WEAKENING MID-LEVEL LAPSE RATES SQUELCH
ADVANCING CONVECTION. HAVE CONTINUED SCHC FOR THE WESTERN HALF OF
THE CWA...BUT IT WILL LIKELY BE A DAY WHERE UPDATES NEED TO BE MADE
IN A NOWCAST MANNER AS CONVECTION TRENDS BECOME DETERMINED.
MINS TONIGHT WILL REMAIN WELL ABOVE NORMAL WITH CONTINUED SW WINDS
AND WAA...FALLING ONLY INTO THE MID 70S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...THE HOTTEST DAY OF THE YEAR SO FAR
EXPECTED ON THURSDAY. TEMPS WILL SOAR INTO THE MID 90S AS STRONG
WESTERLY DOWNSLOPE FLOW DEVELOPS THROUGH THE LOW LEVELS OF THE
ATMOSPHERE AND RIDGE EXTENDS INTO THE CAROLINAS THROUGH THE MID
TO UPPER LEVELS. MODELS SHOW W WINDS UP TO 30 TO 40 KT JUST ABOVE
THE SURFACE WITH H5 HEIGHTS UP TO 589 DEM. AT THE SAME TIME DEW
POINT TEMPS WILL REMAIN AROUND 70 DEGREES. TEMPS LOOKS LIKE THEY
WILL BE WARMEST ACROSS INLAND AREAS WITH PEAK ACROSS NORTHEAST
SOUTH CAROLINA. THE DEWPOINT TEMPS WILL BE HIGHEST THROUGH THE
MORNING HOURS BUT ONCE MIXING OCCURS READINGS WILL DROP INTO THE
60S INLAND WITH GREATEST VALUES ACROSS GEORGETOWN AND HORRY
COUNTIES IN THE AFTERNOON. THESE TWO COUNTIES WILL MOST LIKELY
SURPASS HEAT ADVISORY CRITERIA WITH APPARENT TEMPERATURES UP ABOVE
105 F...WHILE THE REST OF SOUTH CAROLINA ZONES WILL BE CLOSE.
SOUTHEAST NORTH CAROLINA WILL FEEL CLOSER TO 100 DEGREES F.
AFTER SUCH A WARM AND DRY DAY ON THURSDAY...A COLD FRONT WILL
APPROACH FROM THE NORTHWEST. IT LOOKS LIKE THE BEST DYNAMICS WILL
COME TOGETHER IN THE EVENING HOURS AS A SHORTWAVE PUSHES THE FRONT
EAST ACROSS THE AREA. THE BEST SHORTWAVE ENERGY WILL REMAIN TO OUR
NORTH BUT STILL IMPRESSIVE LIFT AND MOISTURE OVER LOCAL AREA TO
PRODUCE POTENTIAL FOR SEVERE THUNDERSTORMS. CAPE VALUES UP TO 2-3K
J/KG WITH STEEP MID LEVEL LAPSE RATES WILL SUPPORT POTENTIAL FOR
STRONG TO SEVERE STORMS. THE STRONG STEERING FLOW WILL DRIVE
THESE STORMS RAPIDLY THROUGH THE AREA AND OFF THE COAST THROUGH
THE EVENING. THE ONE INHIBITING FACTOR WILL BE THE LOSS OF SURFACE
HEATING ALTHOUGH WITH TEMPS WELL INTO THE 90S IN THE
AFTN...READINGS WILL STILL BE HIGH THROUGH THE EVENING HOURS. ONE
OTHER LIMITING FACTOR WILL BE THE LACK OF GREAT MOISTURE RETURN
FROM THE GULF. THEREFORE EXPECT MOST ACTIVITY TO BE FOCUSED ALONG
AND JUST AHEAD OF FRONTAL BOUNDARY MOVING THROUGH RAPIDLY THROUGH
LATE EVENING. AFTER MIDNIGHT MOST OF THE ACTIVITY WILL MAINLY BE
CONFINED TO COASTAL COUNTIES OR OFF SHORE AS COLD FRONT MOVES
THROUGH. RAPID DRYING WILL FOLLOW WITH PCP WATER VALUES DROPPING
FROM 1.9 INCHES JUST AHEAD AND ALONG COLD FRONT DOWN TO LESS THAN
AN INCH BY DAYBREAK FRIDAY.
DEEP DRY NORTHERLY FLOW WILL KEEP TEMPS IN THE MID 80S FOR HIGHS
ON FRIDAY. THIS COMBINED WITH DEWPOINT TEMPS DOWN A GOOD 10
DEGREES WILL MAKE IT FEEL RELATIVELY COOLER ON FRIDAY. MAY SEE
SOME CU BUILD UP WITH RESIDUAL MOISTURE FROM RAINFALL THE NIGHT
BEFORE BUT OVERALL WILL SEE PLENTY OF SUNSHINE. WINDS WILL WEAKEN
THROUGH THE DAY ON FRI AS HIGH PRESSURE MOVES INTO THE CAROLINAS.
EXPECT DECENT RADIATIONAL COOLING FRI NIGHT WITH TEMPS COOLING
DOWN INTO THE MID 60S.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...HIGH PRESSURE WILL BUILD DOWN OVER THE
CAROLINAS AS MID TO UPPER RIDGE MOVES IN FROM THE WEST. A LIGHT
NORTHERLY FLOW ON FRONT END OF HIGH WILL LIGHTEN AND BECOME MORE
VARIABLE ON SATURDAY AS THE CENTER SHIFTS CLOSER OVERHEAD. A LIGHT
RETURN FLOW WILL SET UP SAT NIGHT INTO SUNDAY AS THE HIGH SHIFTS
OFF SHORE. OVERALL EXPECT SEASONABLE WEATHER WITH PLENTY OF
SUNSHINE AND TEMPS RIGHT AROUND NORMAL...IN THE MID 80S DURING THE
DAY AND MID 60S OVERNIGHT. SFC DEWPOINTS INITIALLY WILL BE LOWER
BUT WILL CREEP UP BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK
PRODUCING SLIGHTLY MORE HUMID WEATHER. PCP WATER VALUES WILL
REMAIN CLOSER TO AN INCH THROUGH THE WEEKEND INTO EARLY NEXT WEEK.
BY LATE MONDAY INTO TUESDAY THE RIDGE ALOFT BEGINS TO BREAK DOWN
AS A SHORTWAVE DIGS DOWN FROM THE GREAT LAKES AND PUSHES A COLD
FRONT EAST BY TUESDAY. DEEPER LAYER MOISTURE WILL SET UP AHEAD OF
THE FRONT WITH PCP WATER VALUES INCREASING UP TO 1.75 INCHES IN A
DEEP SOUTHWESTERLY FLOW. EXPECT MORE ACTIVE WEATHER BY TUES
AFTERNOON AS COLD FRONT APPROACHES. RETURN FLOW NEXT WEEK WILL
LEAD TO TEMPS INCREASING A FEW DEGREES ABOVE CLIMO MON AND TUE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...A HOT DAY IN STORE WITH LIGHT SOUTHWEST WINDS. ANY FOG
AT THE START OF TAF TIME WILL QUICKLY MIX OUT BEFORE 13Z. A THERMAL
TROUGH WILL SET UP TODAY ON THE LEE SIDE OF THE APPALACHIANS. AN
ISOLATED THUNDERSTORM MAY DROP SOUTHEAST AROUND MAX HEATING...BUT
WILL LEAVE VCTS OUT OF THE WESTERN TAFS FOR NOW. TONIGHT...VFR
CONDITIONS UNTIL 08-09Z AS ANOTHER ROUND OF SHALLOW FOG IS EXPECTED.
NEARLY CALM WINDS.
EXTENDED OUTLOOK...ISOLATED SHOWERS/THUNDERSTORMS WITH TEMPO PERIODS
OF MVFR/IFR POSSIBLE THURSDAY EVENING INTO FRIDAY MORNING. OTHERWISE
VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM WEDNESDAY...CONTINUED SW WINDS AROUND OFFSHORE HIGH
PRESSURE WILL KEEP SW WINDS AND A SW WIND CHOP PREDOMINANT OVER THE
WATERS. SEAS CURRENTLY 2-4 FT WILL REMAIN STATUS QUO THROUGH THE
PERIOD...WITH SW WINDS OF 10-15 KTS PERSISTENT. THE EXCEPTION TO
THIS WILL BE WITHIN THE INNER FEW NM IN THE SEA BREEZE
BOUNDARY...WITH A SLIGHTLY BACKING TO SOUTH WILL OCCUR AS WELL AS AN
INCREASE IN SPEEDS...WITH GUSTS UP TO 20 KTS. SEAS WILL REMAIN 2-4
FT IN THIS ZONE...BUT WILL BECOME MORE CHOPPY THANKS TO SHORTER
PERIODS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...WINDS WILL INCREASE OUT OF THE SW THROUGH
THURSDAY AS COLD FRONT APPROACHES FROM THE WEST. WINDS WILL START
OUT AROUND 15 KTS BUT WILL REACH UP TO 20 TO 25 KTS THURS EVENING
JUST AHEAD OF THE COLD FRONT. THESE WINDS WILL HELP DRIVE SEAS UP
FROM 2 TO 4 FT EARLY THURS UP TO 4 TO 6 FT THURS EVENING REACHING
SMALL CRAFT CRITERIA LATE THURS AFTN INTO THURSDAY EVENING.
ONCE COLD FRONT CROSSES THE WATERS AFTER MIDNIGHT THURS NIGHT INTO
EARLY FRIDAY...THE WINDS WILL VEER AROUND TO THE NORTHWEST. SEAS
WILL DROP DOWN BELOW SCA QUICKLY OVERNIGHT AND WILL CONTINUE TO
SUBSIDE IN A WEAKENING OFF SHORE FLOW THROUGH FRIDAY. SEAS WILL BE
2 TO 3 FT MOST WATERS BY FRI EVENING.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...
HIGH PRESSURE WILL SHIFT CLOSER OVERHEAD ON SATURDAY AND THEN WILL
SHIFT FURTHER OFF THE COAST BY SATURDAY NIGHT INTO SUNDAY.
THEREFORE WINDS WILL VEER AROUND FROM NORTHERLY ON SATURDAY TO
SOUTHERLY BY SUNDAY REMAINING AROUND 10 KT OR LESS. WINDS WILL
SPIKE UP IN SEA BREEZE EACH AFTERNOON IN NEAR SHORE WATERS. SEAS
WILL REMAIN 3 FT OR LESS THROUGH MUCH OF THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...43
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1100 AM EDT WED JUN 12 2013
.SYNOPSIS...
A DEEPENING LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL
PROGRESS FROM THE CENTRAL PLAINS INTO THE OHIO VALLEY TONIGHT...THEN
TRACK EAST THROUGH THE MID ATLANTIC AND CAROLINAS ON THURSDAY. DRY
HIGH PRESSURE WILL BUILD INTO THE REGION IN THE WAKE OF THE COLD
FRONT THURSDAY NIGHT AND FRIDAY.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 1100 AM WEDNESDAY...
AN UPPER LEVEL RIDGE CENTERED OVER THE SOUTHERN PLAINS WILL
STRENGTHEN SOMEWHAT TODAY WITH MINOR HEIGHT RISES ACROSS THE MID
ATLANTIC. SMALL AMPLITUDE DISTURBANCES IN NW FLOW ALOFT ARE
EXPECTED TO TRACK SOUTHEAST INTO THE CAROLINAS THIS AFTERNOON
THROUGH TONIGHT WHILE A MUCH MORE POTENT SHORTWAVE CENTERED ATOP THE
RIDGE IN THE NORTHERN PLAINS THIS MORNING WILL TRACK INTO THE TN/OH
VALLEY TONIGHT. A WEAK SURFACE TROUGH ACROSS CENTRAL NC WILL PERSIST
ACROSS WESTERN/CENTRAL NC WITH A LIGHT SW SURFACE WIND BECOMING MORE
WESTERLY THIS AFTERNOON.
WE HAVE BEEN MONITORING A REGION OF ISOLATED CONVECTION IN THE
CENTRAL APPALACHIANS THAT DEVELOPED OVERNIGHT. THE FACT THIS
DEVELOPED DURING AN ATYPICAL TIME OF DAY SUGGEST THAT SOME MESOSCALE
FORCING IS LIKELY DRIVING THIS AND IT APPEARS TO BE DEVELOPING IN A
REGION OF WARM ADVECTION AND ENHANCED MID LEVEL FLOW. CONVECTION
ALLOWING MODELS PROVIDE A VARIETY OF SOLUTIONS WITH THIS CONVECTION:
THE 00 UTC ARW/NMM HI RES WINDOWS SUGGEST SOME OF THE CONVECTION
WILL PERSIST AND GROW INTO A CLUSTER OF CONVECTION AROUND MIDDAY AND
SWEEP SOUTHEAST ACROSS THE PIEDMONT WHILE THE HRRR SUGGESTS THAT
ONGOING CONVECTION WILL WEAKEN WITH LITTLE ADDITIONAL REDEVELOPMENT
LIKELY. WITH RECENT RADAR TRENDS SUGGESTING A DECREASE IN
INTENSITY/COVERAGE OF THE CONVECTION AND THE PERSISTENCE OF A MID
LEVEL CAPPING INVERSION...HAVE OPTED TO REMOVE SLIGHT CHANCE POPS IN
THE EAST THIS AFTERNOON AND HIGHLIGHT THE FAR WEST DURING THE EARLY
TO MID AFTERNOON PERIOD FOR SLIGHT CHC POPS...ESPECIALLY ALONG THE
YADKIN RIVER.
CONVECTIVE DEBRIS CLOUDS ARE ALREADY SPREADING ACROSS THE WESTERN
PIEDMONT AND WILL SWEEP INTO THE EASTERN PIEDMONT AND SANDHILLS THIS
AFTERNOON. THE THICKER CLOUDS CLOSE TO THE YADKIN SHOULD BE
SUFFICIENT ENOUGH TO RETARD TEMPERATURES A DEGREE OR TWO. BUT WE
STILL EXPECT HIGHS TO RANGE IN THE 88 TO 95 RANGE TODAY. EXPECT LOWS
OVERNIGHT IN THE 69 TO 73 RANGE. -BLAES/VINCENT
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 AM WEDNESDAY...
...SEVERE WEATHER EXPECTED THURSDAY AFTERNOON AND EVENING...
THURSDAY AND THURSDAY NIGHT:
AN UNSEASONABLY AMPLIFIED PATTERN WILL PERSIST ON THU...
CHARACTERIZED BY A STRONG UPPER LEVEL RIDGE OVER THE CENTRAL CONUS
AND NW FLOW ALOFT DOWNSTREAM ACROSS THE TN/OH VALLEY AND
MID-ATLANTIC. ROBUST SHORTWAVE ENERGY (AND AN ATTENDANT SFC LOW) IN
THE OH VALLEY THU MORNING WILL TRACK EAST ACROSS THE MID-ATLANTIC
THU AFTERNOON AND EVENING. MODERATE INSTABILITY (1500-2500 J/KG
MLCAPE) IS EXPECTED ACROSS CENTRAL NC...IN ASSOCIATION WITH STEEP
(6.5-7.5 C/KM) MID-LEVEL LAPSE RATES AND SEASONABLE BOUNDARY LAYER
MOISTURE. STRENGTHENING WESTERLY FLOW ALOFT IN ADVANCE OF THE
SHORTWAVE WILL RESULT IN 0-6 KM SHEAR ON THE ORDER OF 25-40 KT
(STRONGEST NORTH)...SUFFICIENT FOR ORGANIZED CONVECTION...ESPECIALLY
IN THE PRESENCE OF MODERATE INSTABILITY AND STEEP MID-LEVEL LAPSE
RATES.
SOME UNCERTAINTY PERSISTS WITH REGARD TO THE SPECIFICS OF THIS
SYSTEM GIVEN SMALL VARIANCES IN TIMING AND ONGOING CONVECTION /MCS
ACTIVITY/ EXPECTED TO TRACK INTO THE APPALACHIANS THU MORNING. GIVEN
EXCELLENT SYNOPTIC FORCING...MODERATE DESTABILIZATION AND FAVORABLE
DEEP-LAYER SHEAR...A SIGNIFICANT SEVERE WEATHER EPISODE IS EXPECTED
ACROSS THE REGION THU AFTERNOON AND EVENING. FROM A PATTERN
RECOGNITION STANDPOINT...THE EXPECTED ENVIRONMENT IN CENTRAL NC
WOULD PRIMARILY SUPPORT AN ENHANCED THREAT OF DAMAGING WINDS GIVEN
UNIDIRECTIONAL DEEP-LAYER SHEAR...SPEEDY MID-LEVEL FLOW AND STRONG
EVAP COOLING POTENTIAL ASSOC/W THE MODIFIED EML IN PLACE AND
INVERTED-V PROFILES IN THE BOUNDARY LAYER. W/REGARD TO CONVECTIVE
MODE...EXPECT A RELATIVELY NARROW WINDOW FOR ANY DISCRETE CONVECTION
PRIOR TO RAPID UPSCALE GROWTH INTO AN MCS GIVEN HIGH DCAPE /STRONG
COLD POOLS/ AND MODERATE INSTABILITY. THE LATEST GUIDANCE SUGGESTS
THAT THE TORNADO THREAT WOULD LIKELY REMAIN WELL TO THE NORTH (I.E.
NORTHERN VA/MD/PA/NJ) AND OTHER PORTIONS OF THE MID-ATLANTIC
COAST...IN CLOSER VICINITY TO THE SFC LOW TRACK AND WARM FRONT AND
BETTER LOW-LEVEL DIRECTIONAL SHEAR. WITH EXPECTED MCS ACTIVITY AND
OUTFLOW PROGRESSING INTO THE MOUNTAINS THU MORNING AND A POTENTIAL
FOR HINDERED DESTABILIZATION MID/LATE THU MORNING INTO EARLY THU
AFTERNOON IN THE FAR W/NW PIEDMONT...HAVE DECREASED PRECIP CHANCES
TO 40% IN THAT AREA...WITH PRECIP CHANCES AT 50% IN VICINITY OF THE
HWY 1 CORRIDOR AND 60-70% EAST OF INTERSTATE 95. EXPECT THE BEST
SEVERE THREAT EAST OF HWY 1 AT THIS TIME. HIGHS LOWER TO MID
90S...WARMEST EAST...THOUGH CONFIDENCE IS LOWER THAN NORMAL GIVEN
UNCERTAINTY W/REGARD TO MCS ACTIVITY/CLOUD COVER THAT MAY PROGRESS
INTO WESTERN PORTIONS OF THE STATE IN THE MORNING. EXPECT LOWS THU
NIGHT IN THE MID TO UPPER 60S IN THE WAKE OF A COLD FRONTAL PASSAGE
AS THE SHORTWAVE AND ATTENDANT SFC LOW TRACK OFFSHORE THE
MID-ATLANTIC. -VINCENT
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
FRIDAY AND FRIDAY NIGHT...THE LONGWAVE TROUGH MOVES EAST
FRIDAY...WITH AMPLE NVA IN THE MID-LEVELS TAKING PLACE FRIDAY NIGHT.
THE MEAN AIR MASS IS DRY...WITH A SLIGHT INCREASE IN OVERALL
MOISTURE TOWARD THE NORTHEAST PART OF THE STATE...INCLUDING THE
NORTHERN COASTAL PLAIN...CLOSER TO THE DEPARTING MID-LEVEL LOW. THE
GFS FORECASTS LINGERING...HIGHER PRECIPITABLE WATER VALUES NEAR AN
INCH TOWARD KIXA FRIDAY AFTERNOON...ALTHOUGH GFS BUFR SOUNDINGS AS
WELL AS NAM BUFR SOUNDINGS ARE STABLE AND CAPPED AROUND 700MB.
INTERESTINGLY BUT NOT TERRIBLY SURPRISING GIVEN THE STRENGTH OF THE
DEPARTING UPPER LOW...THE NAM AND GFS PRODUCE MEAGER...JUST
NOTICEABLE QPF MAINLY JUST EAST OF CENTRAL NORTH CAROLINA OVER THE
NORTHEAST PART OF THE STATE DURING FRIDAY AFTERNOON. SIMILAR
SCENARIOS HAVE OCCURRED IN THE RECENT PAST...BEHIND STRONG MID-LEVEL
SYSTEMS WHERE ENOUGH MOISTURE LINGERS TO RESULT IN ISOLATED SHOWERS
OR SPRINKLES SKIRTING OR MOVING INTO CENTRAL NORTH CAROLINA FROM THE
NORTHEAST. ON FRIDAY...WHILE A SPRINKLE MAY OCCUR LATE IN THE DAY
TOWARD KIXA...THE GFS FORECAST COMBINATION OF BEST 850MB AND 700MB
MOISTURE RESIDES JUST EAST OF CENTRAL NORTH CAROLINA BETWEEN 18Z
FRIDAY AND 00Z SATURDAY. AS A RESULT...WILL KEEP THIS FORECAST
DRY...SHOWING A RELATIVELY HIGHER AMOUNT OF CLOUDS IN THE AREA
DURING THE AFTERNOON THROUGH THE EVENING MAINLY FROM WILSON NORTH.
1000-850MB THICKNESSES AND BIAS CORRECTED TEMPERATURE GUIDANCE ALL
FAVOR HIGHS NEAR THE COOLER MET GUIDANCE FOR FRIDAY...AND BUFR
SOUNDINGS SHOW THERE MAY BE ENOUGH HIGH-BASED CU/SC FOR HIGHS TO BE
TEMPERED SOMEWHAT FROM THE WARMER MAV VALUES. OVERNIGHT LOWS 57 TO
62. EXPECT A FEW WIND GUSTS IN THE UPPER TEENS TO POSSIBLY LOWER 20S
KNOTS FRIDAY WITH INITIAL MIXING IN THE TIGHT GRADIENT BEHIND THE
DEPARTING LOW.
FOR THE PERIOD SATURDAY THROUGH TUESDAY...THE FORECAST FOR SATURDAY
REMAINS DRY AS A STABLE AND DRY AIR MASS UNDER HIGH PRESSURE IS
ANTICIPATED. AS THE WEEKEND ENDS AND WE APPROACH THE BEGINNING OF
THE NEXT WORK WEEK...GUIDANCE IS CONSISTENT IN PUSHING MODESTLY
STRONG MID-LEVEL SHORTWAVES ATOP THE RIDGE TO OUR WEST...EVENTUALLY
FLATTENING THAT UPPER RIDGE. THE CENTER OF SURFACE HIGH PRESSURE
MOVES OFF TO THE EAST OF CENTRAL NORTH CAROLINA BY SUNDAY
AFTERNOON...BRINGING MORE MOISTURE INTO CENTRAL NORTH CAROLINA.
BASED ON THE CONSENSUS OF THE LATEST GFS AND THE 12Z ECMWF...THE
APPROACH OF THE NEXT SURFACE FRONT WILL BE AT LEAST LATE TUESDAY...
WITH THE TYPICAL PIEDMONT TROUGH IN PLACE FOR SUNDAY INTO MONDAY.
WHILE THERE IS A NOTICEABLE INCREASE IN 850MB THETA-E AIR SUNDAY AS
PRECIPITABLE WATER VALUES RISE FROM UNDER AN INCH SATURDAY TO CLOSE
TO 1.5 INCHES ON THE GFS...AND THERE IS A SLIGHT STEEPENING OF THE
MID-LEVEL LAPSE RATES...GFS BUFR SOUNDINGS ARE STILL CAPPED TO DEEP
CONVECTION SUNDAY AFTERNOON. THERE IS A LITTLE CONCERN ABOUT
UPSTREAM DEVELOPMENT MOVING INTO THE REGION...BUT THE GFS THICKNESS
PROFILE WOULD SUGGEST ANY SUCH DEVELOPMENT WOULD TEND TO TRACK WELL
NORTH AND NORTHEAST OF THE AREA. IF ANYTHING DEVELOPS AT ALL
SUNDAY...IT IS CURRENTLY EXPECTED TO BE VERY ISOLATED. AS HEIGHTS
ALOFT CONTINUE TO FALL...AND LAPSE RATES AT LEAST ON THE GFS STEEPEN
EVER SO SLIGHTLY MONDAY COMPARED TO SUNDAY AS MOISTURE CONTINUES TO
INCREASE...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ARE POSSIBLE.
THE GFS BUFR SOUNDINGS ARE STILL WEAKLY CAPPED MONDAY AROUND 750MB...
AND THE COARSE 12Z ECMWF SOUNDINGS ACTUALLY ARE MORE STABLE MONDAY
THAN SUNDAY...SO WILL KEEP CHANCES FOR PRECIPITATION SLIGHT AT THIS
TIME...AND LOWEST IN THAT RANGE OVER THE SANDHILLS AND SOUTHERN
COASTAL PLAIN. BY TUESDAY...WITH THE SLOW APPROACH OF THE FRONT...
AND A CONTINUED INCREASE IN MOISTURE AND COOLING ALOFT...AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED. OVERNIGHT LOWS
WILL GRADUALLY RISE FROM THE LOWER TO MID 60S SATURDAY NIGHT TO 69
TO 74 BY MONDAY NIGHT. AFTER HIGHS SATURDAY CLOSE TO 1000-850MB
THICKNESSES IN THE LOWER TO MID 80S...FORECAST HIGHS WILL BE IN THE
MID 80S TO AROUND 90...WARMEST MONDAY WITH THIS FORECAST. ONE
POSSIBLE ALTERNATIVE IS THAT SUNDAY ACTUALLY ENDS UP WARMER THAN
MONDAY WHEN THE AIR IS A LITTLE DRIER AS THE SOUTHWEST SURFACE
FLOW INITIALLY BECOMES MORE ENTRENCHED. FOR THAT DAY...LEANED ON THE
HIGH SIDE OF THE AVAILABLE GUIDANCE SUITE. -DJF
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 645 AM WEDNESDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. THE ONLY
POSSIBLE EXCEPTION WILL BE A SMALL CHANCE FOR ISOLATED SHOWERS AND
THUNDERSTORMS...BETWEEN 12-18Z AT THE INT/GSO TERMINALS AND PERHAPS
AT ANY TERMINAL THIS AFTERNOON...THOUGH THE RELATIVE BEST CHANCE
WILL REMAIN AT THE INT/GSO TERMINALS. CALM OR LIGHT/VARIABLE WINDS
THIS MORNING WILL BECOME WEST OR SOUTHWEST AT 7-13 KT THIS
AFTERNOON...REMAINING SOUTHWEST AT 5-10 KT TONIGHT AS A DEEPENING
LOW PRESSURE SYSTEM TRACKS INTO THE OH VALLEY.
LOOKING AHEAD:
ADVERSE AVIATION CONDITIONS IN THE FORM OF SCATTERED TO WIDESPREAD
SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE DAY THURSDAY. ANY
THUNDERSTORMS THAT DEVELOP WILL BE CAPABLE OF PRODUCING DAMAGING SFC
WIND GUSTS IN EXCESS OF 50 KNOTS. AT THIS TIME...THE BEST CHANCE FOR
AFTERNOON CONVECTION AND SEVERE WEATHER WILL BE AT THE RDU/FAY/RWI
TERMINALS. ASIDE FROM CONVECTION...EXPECT BREEZY WEST/SOUTHWEST
WINDS THURSDAY AFTERNOON...SUSTAINED AT 15-20 KT WITH GUSTS UP TO
25-30 KT. WINDS WILL SHIFT TO THE NORTHWEST AT 10-15 KT IN THE WAKE
OF A COLD FRONTAL PASSAGE THURSDAY EVENING INTO THURSDAY NIGHT.
EXPECT DRY/VFR CONDITIONS TO PREVAIL IN THE WAKE OF THE FRONT FRIDAY
THROUGH THE WEEKEND. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...BLAES/VINCENT
SHORT TERM...VINCENT
LONG TERM...DJF
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1019 PM EDT THU JUN 13 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD SOUTHEAST AND BE OVER THE AREA BY FRIDAY
NIGHT. THE HIGH WILL MOVE TO THE CAROLINA COAST BY SATURDAY NIGHT. A
WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA SATURDAY NIGHT AND
BECOME NEARLY STATIONARY NORTHEAST OF THE REGION. LOW PRESSURE WILL
MOVE SOUTHEAST ALONG THE FRONT TO THE CENTRAL GREAT LAKES BY MONDAY
NIGHT AND TO THE NEW ENGLAND COAST BY TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
BAND OF SHOWERS OVER NE OH/NW PA IS BREAKING UP AND DECREASING IN
COVERAGE SO HAVE BACKED OFF ON POPS FOR THE REMAINDER OF THE
NIGHT. WILL CARRY PARTLY CLOUDY SKIES DOWN WIND OF LAKE ERIE OVERNIGHT
WHERE MODELS INDICATE SOME PATCHES OF STRATUS MAY DEVELOP.
ORIGINAL DISCUSSION...CYCLONIC FLOW WILL CONTINUE ACROSS THE
EASTERN PORTIONS OF THE FORECAST AREA THIS EVENING AND CAUSE SOME
LIMITED MOISTURE TO ROTATE INTO THE REGION. MOST OF THE CLOUD
COVER OVER THIS AREA IS DIURNAL IN NATURE AND I SUSPECT THAT WE
SHOULD SEE A LOT OF IT DISSIPATE OVERNIGHT. DURING THE EVENING
HOURS...WE CANT RULE OUT A POSSIBLE SHOWER OR SPRINKLE IN THE
EAST. LATEST RADAR SHOWS A NICE BAND OF SHOWERS MOVING SOUTH
ACROSS THE EAST AT THIS TIME. THIS IS IN GOOD AGREEMENT WITH THE
LATEST HRRR MODEL. SO WILL MENTION SPRINKLES AND OR SHOWERS FOR
NOW DISSIPATING THIS EVENING.
THE WESTERN PORTIONS SHOULD SEE THE CLEARING PERSIST WITH SOME
POSSIBLE LAKE EFFECT CLOUDS GETTING IN THE WAY OF A CLEAR SKY
OVERNIGHT. EVERY WHERE ELSE IN BETWEEN...SKIES SHOULD BE PARTLY
CLOUDY WITH FAIR WEATHER.
COLD AIR ADVECTION EXPECTED OVERNIGHT WILL ALLOW TEMPERATURES TO DIP
WELL INTO THE LOWER 50S IN THE EAST AND MIDDLE 50S IN THE WEST. 850
MB TEMPERATURES HOVER AROUND 10 DEGREES C OVER THE FORECAST AREA.
WARMER TEMPERATURES IN THE WEST WILL RESULT IN THE SLIGHTLY HIGHER
SURFACE TEMPERATURES OVERNIGHT AS WELL.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
UPPER LEVEL TROUGH WILL FINALLY EXIT TO THE EAST OVERNIGHT ALLOWING
RIDGE TO BUILD IN FROM THE WEST BY SATURDAY EVENING. THE AMPLIFIED
RIDGE WILL DAMPEN OVER TIME AS IT MOVES EAST AND FLOW WILL BECOME
NEARLY ZONAL. THIS SHOULD HELP TEMPERATURES TO RETURN BACK TO MORE
NORMAL READINGS INTO THE WEEKEND.
FAIR WEATHER WILL BE THE RULE FOR FRIDAY AS THE HIGH PRESSURE
REMAINS THE DOMINANT WEATHER FEATURE DURING THIS PERIOD. THIS WILL
HOWEVER BE SHORT LIVED.
AS HIGH PRESSURE MOVES EAST OF THE AREA SATURDAY...A WARM FRONT WILL
LIFT NORTH ACROSS THE AREA AND BECOME NEARLY STATIONARY BY SATURDAY
NIGHT. THIS FEATURE WILL BRING WITH IT ASSOCIATED MOISTURE AND
SUPPORT ANOTHER CHANCE FOR SHOWERS AND THUNDERSTORMS SATURDAY
AFTERNOON AND SATURDAY NIGHT.
A SERIES OF UPPER LEVEL SHORTWAVE TROUGHS AND ASSOCIATED POSITIVE
VORTICITY ADVECTION AND VORTICITY MAXIMUMS WILL MOVE QUICKLY EAST
ACROSS THE FORECAST AREA. UNFORTUNATE PART IS IF THESE FEATURES SLOW
IN THEIR FORWARD MOTION COMPARED TO THEIR LATE NIGHT SATURDAY NIGHT
ARRIVAL AND SUNDAY MORNING...WE COULD SEE ANOTHER ROUND OF SEVERE
WEATHER THAT COULD AFFECT THE FORECAST AREA. WE OBVIOUSLY WILL BE
MONITORING THIS SITUATION AND SEE HOW IT DEVELOPS. BUT WILL KEEP THE
MENTION OUT OF THE HAZARDOUS WEATHER OUTLOOK DUE TO INSTABILITY NOT
LOOKING TOO FAVORABLE.
YET ANOTHER IMPULSE ALOFT WILL PUSH EAST ACROSS THE AREA SUNDAY
NIGHT KEEPING THE THREAT FOR SHOWERS AND THUNDERSTORMS GOING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE MODELS CONTINUE TO STRUGGLE WITH THE TIMING OF ANOTHER WAVE THAT
MAY MOVE INTO THE CENTRAL GREAT LAKES ON MONDAY. SO AFTER A BRIEF
LULL IN THUNDERSTORM ACTIVITY LATE SUNDAY NIGHT INTO MONDAY MORNING
WE SHOULD SEE THUNDERSTORM CHANCES RETURN MONDAY AFTERNOON AND
EVENING. THERE MAY BE SOME LINGERING LIGHT SHOWERS OR THUNDERSTORMS
TUESDAY AS HIGH PRESSURE BEGINS TO BUILD INTO THE REGION FOR
WEDNESDAY.
MONDAY LOOKS AS IF IT WILL BE THE WARMEST DAY OF THE EXTENDED WITH
MOST LOCATIONS WITHING A FEW DEGREES OF 80. COOLER FOR TUESDAY AND
WEDNESDAY WITH HIGHS BACK INTO THE LOWER AND MIDDLE 70S.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
BAND OF SHOWERS WILL CONTINUE THE FIRST HALF OF TONIGHT ACROSS
EXTREME NORTHEAST OHIO...SHIFTING INTO NORTHWEST PENNSYLVANIA AND
THEN PROBABLY DIMINISHING. THE NEXT SHORT WAVE DROPPING SOUTH WILL
PROBABLY CAUSE SCT-BKN CLOUDS TO FLARE BACK UP LATE TONIGHT/FRIDAY
MORNING. MVFR CEILINGS ARE LIKELY ACROSS NE OH/NW PA WITH
ISOLATED IFR CEILINGS EXTREME NE OH/NW PA FRIDAY MORNING. A SHOWER
CANNOT BE RULED OUT EARLY FRIDAY MORNING EXTREME NE OH/NW PA BUT
KEPT THE TAF FORECASTS DRY. CEILINGS SHOULD DISSIPATE OR BECOME VFR
FRIDAY AFTERNOON...THEN BECOME CLEAR BY LATE AFTERNOON/EVENING.
.OUTLOOK...NON VFR POSSIBLE IN PATCHY MORNING FOG SATURDAY.
NON VFR ALSO POSSIBLE SATURDAY NIGHT THROUGH MONDAY IN SHOWERS AND
THUNDERSTORMS. NON VFR CEILINGS MAY LINGER INTO TUESDAY.
&&
.MARINE...
WINDS REMAIN STRONG ENOUGH FOR WAVES TO REMAIN IN THE 3 TO 5 FOOT
RANGE INTO THE EVENING. WESTERN AREAS MAY DECREASE FASTER THAN
CURRENT THINKING BUT WILL KEEP THE SMALL CRAFT ADVISORY GOING FOR A
BIT LONGER. OTHERWISE HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE
REGION FOR TONIGHT THROUGH SATURDAY. AS THE HIGH MOVES EASTERLY
WINDS WILL TURN TO THE SOUTHWEST. LOW PRESSURE WILL MOVE ACROSS THE
LAKE AT SOME POINT ON MONDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...KEC/LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...MULLEN
AVIATION...KOSARIK
MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
742 PM EDT THU JUN 13 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD SOUTHEAST AND BE OVER THE AREA BY FRIDAY
NIGHT. THE HIGH WILL MOVE TO THE CAROLINA COAST BY SATURDAY NIGHT. A
WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA SATURDAY NIGHT AND
BECOME NEARLY STATIONARY NORTHEAST OF THE REGION. LOW PRESSURE WILL
MOVE SOUTHEAST ALONG THE FRONT TO THE CENTRAL GREAT LAKES BY MONDAY
NIGHT AND TO THE NEW ENGLAND COAST BY TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
UPDATED THE FORECAST TO RAISE POPS ACROSS MAINLY
ASHTABULA/TRUMBULL/MAHONING COUNTIES WHERE PERSISTENT BAND OF
SHOWERS HAS SET UP. THESE SHOWERS HAVE DEVELOPED ON THE NORTHWEST
FLANK OF THE 700MB LOW IN AN AREA OF MID-LEVEL DEFORMATION ON THE
FRINGE OF THE DEEPER MOISTURE. LIFT IS BEING ENHANCED BY THE NEXT SHORTWAVE
DROPPING INTO THE TROUGH FROM THE NORTHWEST. THE DEEPER MOISTURE
WILL PULL EAST THIS EVENING AND MAY SEE THE SHOWERS SHIFT INTO
PENNSYLVANIA BEFORE DISSIPATING.
PREVIOUS DISCUSSION...CYCLONIC FLOW WILL CONTINUE ACROSS THE
EASTERN PORTIONS OF THE FORECAST AREA THIS EVENING AND CAUSE SOME
LIMITED MOISTURE TO ROTATE INTO THE REGION. MOST OF THE CLOUD
COVER OVER THIS AREA IS DIURNAL IN NATURE AND I SUSPECT THAT WE
SHOULD SEE A LOT OF IT DISSIPATE OVERNIGHT. DURING THE EVENING
HOURS...WE CANT RULE OUT A POSSIBLE SHOWER OR SPRINKLE IN THE
EAST. LATEST RADAR SHOWS A NICE BAND OF SHOWERS MOVING SOUTH
ACROSS THE EAST AT THIS TIME. THIS IS IN GOOD AGREEMENT WITH THE
LATEST HRRR MODEL. SO WILL MENTION SPRINKLES AND OR SHOWERS FOR
NOW DISSIPATING THIS EVENING.
THE WESTERN PORTIONS SHOULD SEE THE CLEARING PERSIST WITH SOME
POSSIBLE LAKE EFFECT CLOUDS GETTING IN THE WAY OF A CLEAR SKY
OVERNIGHT. EVERY WHERE ELSE IN BETWEEN...SKIES SHOULD BE PARTLY
CLOUDY WITH FAIR WEATHER.
COLD AIR ADVECTION EXPECTED OVERNIGHT WILL ALLOW TEMPERATURES TO DIP
WELL INTO THE LOWER 50S IN THE EAST AND MIDDLE 50S IN THE WEST. 850
MB TEMPERATURES HOVER AROUND 10 DEGREES C OVER THE FORECAST AREA.
WARMER TEMPERATURES IN THE WEST WILL RESULT IN THE SLIGHTLY HIGHER
SURFACE TEMPERATURES OVERNIGHT AS WELL.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
UPPER LEVEL TROUGH WILL FINALLY EXIT TO THE EAST OVERNIGHT ALLOWING
RIDGE TO BUILD IN FROM THE WEST BY SATURDAY EVENING. THE AMPLIFIED
RIDGE WILL DAMPEN OVER TIME AS IT MOVES EAST AND FLOW WILL BECOME
NEARLY ZONAL. THIS SHOULD HELP TEMPERATURES TO RETURN BACK TO MORE
NORMAL READINGS INTO THE WEEKEND.
FAIR WEATHER WILL BE THE RULE FOR FRIDAY AS THE HIGH PRESSURE
REMAINS THE DOMINANT WEATHER FEATURE DURING THIS PERIOD. THIS WILL
HOWEVER BE SHORT LIVED.
AS HIGH PRESSURE MOVES EAST OF THE AREA SATURDAY...A WARM FRONT WILL
LIFT NORTH ACROSS THE AREA AND BECOME NEARLY STATIONARY BY SATURDAY
NIGHT. THIS FEATURE WILL BRING WITH IT ASSOCIATED MOISTURE AND
SUPPORT ANOTHER CHANCE FOR SHOWERS AND THUNDERSTORMS SATURDAY
AFTERNOON AND SATURDAY NIGHT.
A SERIES OF UPPER LEVEL SHORTWAVE TROUGHS AND ASSOCIATED POSITIVE
VORTICITY ADVECTION AND VORTICITY MAXIMUMS WILL MOVE QUICKLY EAST
ACROSS THE FORECAST AREA. UNFORTUNATE PART IS IF THESE FEATURES SLOW
IN THEIR FORWARD MOTION COMPARED TO THEIR LATE NIGHT SATURDAY NIGHT
ARRIVAL AND SUNDAY MORNING...WE COULD SEE ANOTHER ROUND OF SEVERE
WEATHER THAT COULD AFFECT THE FORECAST AREA. WE OBVIOUSLY WILL BE
MONITORING THIS SITUATION AND SEE HOW IT DEVELOPS. BUT WILL KEEP THE
MENTION OUT OF THE HAZARDOUS WEATHER OUTLOOK DUE TO INSTABILITY NOT
LOOKING TOO FAVORABLE.
YET ANOTHER IMPULSE ALOFT WILL PUSH EAST ACROSS THE AREA SUNDAY
NIGHT KEEPING THE THREAT FOR SHOWERS AND THUNDERSTORMS GOING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE MODELS CONTINUE TO STRUGGLE WITH THE TIMING OF ANOTHER WAVE THAT
MAY MOVE INTO THE CENTRAL GREAT LAKES ON MONDAY. SO AFTER A BRIEF
LULL IN THUNDERSTORM ACTIVITY LATE SUNDAY NIGHT INTO MONDAY MORNING
WE SHOULD SEE THUNDERSTORM CHANCES RETURN MONDAY AFTERNOON AND
EVENING. THERE MAY BE SOME LINGERING LIGHT SHOWERS OR THUNDERSTORMS
TUESDAY AS HIGH PRESSURE BEGINS TO BUILD INTO THE REGION FOR
WEDNESDAY.
MONDAY LOOKS AS IF IT WILL BE THE WARMEST DAY OF THE EXTENDED WITH
MOST LOCATIONS WITHING A FEW DEGREES OF 80. COOLER FOR TUESDAY AND
WEDNESDAY WITH HIGHS BACK INTO THE LOWER AND MIDDLE 70S.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
BAND OF SHOWERS WILL CONTINUE THE FIRST HALF OF TONIGHT ACROSS
EXTREME NORTHEAST OHIO...SHIFTING INTO NORTHWEST PENNSYLVANIA AND
THEN PROBABLY DIMINISHING. THE NEXT SHORT WAVE DROPPING SOUTH WILL
PROBABLY CAUSE SCT-BKN CLOUDS TO FLARE BACK UP LATE TONIGHT/FRIDAY
MORNING. MVFR CEILINGS ARE LIKELY ACROSS NE OH/NW PA WITH
ISOLATED IFR CEILINGS EXTREME NE OH/NW PA FRIDAY MORNING. A SHOWER
CANNOT BE RULED OUT EARLY FRIDAY MORNING EXTREME NE OH/NW PA BUT
KEPT THE TAF FORECASTS DRY. CEILINGS SHOULD DISSIPATE OR BECOME VFR
FRIDAY AFTERNOON...THEN BECOME CLEAR BY LATE AFTERNOON/EVENING.
.OUTLOOK...NON VFR POSSIBLE IN PATCHY MORNING FOG SATURDAY.
NON VFR ALSO POSSIBLE SATURDAY NIGHT THROUGH MONDAY IN SHOWERS AND
THUNDERSTORMS. NON VFR CEILINGS MAY LINGER INTO TUESDAY.
&&
.MARINE...
WINDS REMAIN STRONG ENOUGH FOR WAVES TO REMAIN IN THE 3 TO 5 FOOT
RANGE INTO THE EVENING. WESTERN AREAS MAY DECREASE FASTER THAN
CURRENT THINKING BUT WILL KEEP THE SMALL CRAFT ADVISORY GOING FOR A
BIT LONGER. OTHERWISE HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE
REGION FOR TONIGHT THROUGH SATURDAY. AS THE HIGH MOVES EASTERLY
WINDS WILL TURN TO THE SOUTHWEST. LOW PRESSURE WILL MOVE ACROSS THE
LAKE AT SOME POINT ON MONDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR
LEZ142>149.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...KEC/LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...MULLEN
AVIATION...KOSARIK
MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
521 PM EDT WED JUN 12 2013
.SYNOPSIS...
A WARM FRONT WILL BECOME NEARLY STATIONARY ACROSS NORTHERN OHIO AND
NORTHERN PENNSYLVANIA THROUGH THURSDAY MORNING AS LOW PRESSURE MOVES
EAST ALONG THE FRONT. HIGH PRESSURE WILL BUILD SOUTH ACROSS THE AREA
BY SATURDAY MORNING AND TO THE CAROLINA COAST BY SATURDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
UPDATED FOR SEVERE WATCH. CONVECTION NOW DEVELOPING IN IOWA AND
ILLINOIS. THIS IS EXPECTED TO DEVELOP INTO A SQUALL LINE THAT WILL
MOVE INTO WESTERN OHIO LATE THIS EVENING TO AROUND MIDNIGHT. IF
CONVECTION DEVELOPS AHEAD OF THE LINE...IT TOO COULD BECOME
SEVERE. THIS IS A PDS WATCH WITH THE EXPECTATION OF THUNDERSTORMS
CONTAINING DAMAGING WINDS IN EXCESS OF 65 KTS. THERMODYNAMICS
BACKS THIS UP WITH DRY AIR ALOFT CONTRIBUTING TO DOWNDRAFT CAPES
OVER 1000K/KG. SHEAR PROFILES ALSO SUGGEST FORWARD PROPAGATION
ADDING TO WIND POTENTIAL. ROTATING SUPERCELLS ALSO SUPPORTED SO
TORNADOES ARE ALSO POSSIBLE.
PREVIOUS...THE WAITING GAME BEGINS. SO FAR ATMOSPHERE APPEARS TO
BE WELL CAPPED AND IS SUPPRESSING CONVECTION FROM DEVELOPING
UPSTREAM. THE OTHER ISSUE AT HAND IS THE EXTENSIVE DEBRIS CLOUDS
HANGING AROUND. WE NEVER CLEARED OUT OR HAD ANY BREAKS IN THE
OVERCAST AS EXPECTED AND THIS IS ALSO LIMITING ANY DEVELOPMENT
OVER THE REGION.
COORDINATED WITH COFORECASTER...IT APPEARS AN AREA OF CONVERGENCE
HAS SET UP BACK OVER EASTERN IOWA AND NORTHWEST ILLINOIS AT THIS
TIME AND THIS COULD VERY WELL BE THE LOCATION THE THUNDERSTORMS
DEVELOP. LATEST HRRR MODEL SHOWS CONVECTION FIRING OVER THIS AREA AS
WELL AND HAS BEEN PRETTY CONSISTENT FROM RUN TO RUN TODAY. THERE IS
THE POSSIBILITY THAT ACTIVITY COULD DEVELOP AHEAD OF THE MAIN LINE
AS INDIVIDUAL CELLS OVERNIGHT.
LATEST SURFACE ANALYSIS SHOWS DEWPOINT TEMPERATURES RISING INTO THE
LOWER 70S INTO THE SOUTHWEST PORTION OF THE FORECAST AREA AT THIS
TIME. WE SHOULD CONTINUE TO SEE A SURGE OF THE HIGHER DEWPOINT AIR
INTO THE FORECAST AREA AS THE EVENING PROGRESSES. THIS WILL HELP TO
INCREASE THE MOISTURE ACROSS THE REGION PRIMING THE ATMOSPHERE FOR
THE POTENTIAL FOR HEAVY RAIN THAT WE HAVE BEEN EXPECTING.
THE SURGE OF STRONG STORMS WILL ENTER THE AREA AND COULD POSSIBLY
EVOLVE INTO AN OVERRUNNING SITUATION ALONG THE STATIONARY FRONT LATE
TONIGHT. THE SEVERE THREAT WILL TRANSITION INTO A POTENTIAL FLOODING
THREAT WITH LOCALLY HEAVY RAIN FROM THE THUNDERSTORMS. THUNDERSTORMS
WILL BE EFFICIENT RAIN PRODUCERS AND AREAS COULD SEE SUBSTANTIAL
PONDING OF WATER OVERNIGHT ALONG WITH THE RAPID RISES OF RIVERS AND
STREAMS. SEE HYDRO SECTION BELOW.
TROPICAL AIR MASS OVER THE REGION WILL BE ACROSS THE SOUTHERN HALF
OF THE FORECAST AREA. NORTHERN HALF OF THE AREA WILL REMAIN NORTH OF
THE STATIONARY FRONT MOST OF THE NIGHT. AS THE LOW PRESSURE SYSTEM
MOVES EAST...IT WILL PUSH THE FRONT NORTH TO THE LAKE SHORE AS A
WARM FRONT. TEMPERATURES OVERNIGHT IN THE LOWER 70S SOUTH AND UPPER
60S IN THE NORTH.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
LOW PRESSURE IS PROGGED TO PULL OUT TO THE EAST THURSDAY MORNING AS
UPPER LEVEL AMPLIFIED RIDGE BUILDS EAST FORCING UPPER LEVEL TROUGH
OFF THE COAST. AS SURFACE LOW MOVES EAST...ASSOCIATED MOISTURE AND
SUBSEQUENT PRECIPITATION WILL EXIT TO THE EAST AS WELL. HIGH
PRESSURE AT THE SURFACE PUSHES SOUTHEAST ACROSS THE AREA FORCING
DRIER AIR INTO THE REGION FOR THURSDAY NIGHT INTO FRIDAY.
THE HIGH WILL MOVE SOUTHEAST TO THE CAROLINA COAST BY SATURDAY NIGHT
AND THIS WILL SET UP ANOTHER RETURN SOUTHERLY FLOW TO THE FORECAST
AREA. A FAIRLY FAST MOVING SHORTWAVE TROUGH AND ASSOCIATED MOISTURE
WILL BEGIN TO MOVE EAST INTO THE FORECAST AREA SATURDAY INTO
SATURDAY NIGHT AND COULD BRING ANOTHER ROUND OF SHOWERS TO THE
FORECAST AREA.
COLD AIR ADVECTION ASSOCIATED WITH THE HIGH PRESSURE WILL OCCUR ON
THURSDAY BUT WILL BE SHORT LIVED AS HIGH MOVES TO THE SOUTHEAST. AS
MENTIONED EARLIER...RETURN SOUTHERLY FLOW WILL BRING TEMPERATURES
BACK UP INTO THE MIDDLE 70S EAST AND UPPER 70S TO LOWER 80S WEST BY
SATURDAY. LOWS DIPPING BACK TO THE 50S THURSDAY AND FRIDAY NIGHTS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A RIPPLE OF LOW PRESSURE WILL BE MOVING INTO THE REGION ON SUNDAY
WITH SCATTERED THUNDERSTORMS POSSIBLE...ESPECIALLY SUNDAY AFTERNOON.
THE MODELS ARE THEN STRUGGLING WITH THE TIMING OF ANOTHER WAVE THAT
MAY MOVE INTO THE CENTRAL GREAT LAKES ON MONDAY. SO AFTER A BRIEF
LULL IN THUNDERSTORM ACTIVITY LATE SUNDAY NIGHT INTO MONDAY MORNING
WE SHOULD SEE THUNDERSTORM CHANCES RETURN MONDAY AFTERNOON AND
EVENING. THERE MAY BE SOME LINGERING LIGHT SHOWERS OR THUNDERSTORMS
TUESDAY AS HIGH PRESSURE BEGINS TO BUILD INTO THE REGION LATE.
TEMPERATURES THROUGH THE EXTENDED WILL BE WITHIN A FEW DEGREES OF
SEASONAL AVERAGES.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
A WEST TO EAST ORIENTED FRONTAL BOUNDARY WILL REMAIN
QUASISTATIONARY ACROSS CENTRAL OHIO TODAY. A LOW PRESSURE
DISTURBANCE OVER NORTHERN ILLINOIS WILL MAKE ITS WAY EAST ALONG
THIS BOUNDARY TONIGHT...INITIATING THUNDERSTORMS ACROSS THE
FORECAST AREA TONIGHT INTO THURSDAY. THUNDERSTORMS MAY REACH THE
WESTERN TAF SITES SOMETIME AROUND 22Z. THERE IS A CHANCE THAT THIS
DISTURBANCE WILL BECOME FORWARD PROPAGATING...MOVING QUICKLY
THROUGH THE FORECAST AREA. IF THIS OCCURS...A SUBSTANTIAL GUST
FRONT COULD DEVELOP ALONG THE LEADING EDGE OF THE DISTURBANCE.
WILL MONITOR THE THREAT OVER THE NEXT COUPLE OF HOURS TO DETERMINE
WHETHER OR NOT TO ADD A VARIABLE WIND GUST TO TAFS FOR THE 00-04Z
TIME FRAME.
SHOWERS WILL ACCOMPANY THE THUNDERSTORMS THIS EVENING AND WILL
LIKELY PERSIST INTO THURSDAY AS A COLD FRONT MOVES INTO THE AREA.
CEILINGS WILL LOWER TO MVFR OVERNIGHT AND IFR THURSDAY MORNING. MOST
OF THE RAIN WILL OCCUR OVERNIGHT AND EARLY THURSDAY MORNING...WITH
VISIBILITIES DROPPING TO MVFR IN THE HEAVIEST SHOWERS.
CEILINGS WILL BEGIN TO LIFT AND RAIN WILL BEGIN TO CLEAR OUT EARLY
THURSDAY AFTERNOON TOWARDS THE END OF THE TAF PERIOD.
.OUTLOOK...NON VFR CONDITIONS POSSIBLE THURSDAY NIGHT AND SATURDAY
NIGHT AND SUNDAY IN SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
SCATTERED SHOWERS CONTINUE OVER LAKE ERIE THIS AFTERNOON WITH WINDS
VARYING FROM A NORTHEAST TO SOUTHEAST DIRECTION. LATER TONIGHT...A
LOW PRESSURE SYSTEM WILL MOVE EAST ALONG A QUASISTATIONARY BOUNDARY
LYING ACROSS CENTRAL OHIO. SHOWERS AND THUNDERSTORMS WILL
ACCOMPANY THE DISTURBANCE. SOME OF THE THUNDERSTORMS MAY BECOME
SEVERE...WARRANTING A SPECIAL MARINE WARNING.
SHOWERS ARE EXPECTED TO CONTINUE INTO THURSDAY AHEAD OF A COLD
FRONT. MOST OF THE SHOWERS WILL OCCUR OVERNIGHT INTO THURSDAY
MORNING. WINDS WILL INCREASE IN SPEED WITH THE PASSAGE OF THE COLD
FRONT THURSDAY NIGHT. MODELS ARE STILL A BIT UNCERTAIN WITH HOW
STRONG WINDS WILL GET...WHICH WILL AFFECT WAVE HEIGHTS. FOR NOW IT
DOES NOT APPEAR THAT A SMALL CRAFT ADVISORY WILL BE NECESSARY...BUT
THE NEXT FORECAST SHIFT WILL CONTINUE TO MONITOR THE SITUATION.
HIGH PRESSURE WILL BUILD OVER THE LAKE FRIDAY NIGHT AND MOVE EAST
LATE SATURDAY NIGHT. AS THE HIGH MOVES EAST...WINDS WILL TURN TO THE
SOUTHWEST AND PICK UP SPEED. A LOW PRESSURE SYSTEM AND ASSOCIATED
COLD FRONT WILL APPROACH THE AREA ON MONDAY.
&&
.HYDROLOGY...
A FLOOD WATCH IS IN EFFECT FOR THE ENTIRE AREA FROM THE HEAVY
RAINFALL EXPECTED OVERNIGHT AND EARLY THURSDAY. MOISTURE ADVECTION
WILL INCREASE OVER THE AREA THIS AFTERNOON AND NOTABLY OVERNIGHT AS
AN AREA OF LOW PRESSURE MOVES INTO THE REGION FROM THE WEST. THERE
IS SOME INDICATION THAT PRECIPITABLE WATER VALUES COULD REACH 2.0"
WHICH IS ANOMALOUSLY HIGH FOR THIS TIME OF YEAR. THE SHOWERS WILL BE
EFFICIENT RAIN MAKERS AND COULD DROP A QUICK INCH TO AN AREA. THE
THREAT OF TRAINING STORMS IS HIGH SUGGESTING THE THREAT OF A QUICK 2
TO 3 INCHES OF RAIN IS POSSIBLE. RAINFALL RATES THIS HIGH COULD
PRODUCE FLASH FLOODING. THE HEAVIEST RAIN WILL FALL BETWEEN 10 PM
TONIGHT AND 8 AM THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR OHZ011>014-020>023-031>033-038-089.
FLOOD WATCH THROUGH THURSDAY AFTERNOON FOR OHZ003-006>010-
017>019-027>030-036-037-047.
PA...FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR PAZ001>003.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...TK/LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...MULLEN
AVIATION...MULLEN/YEAGER
MARINE...MULLEN/YEAGER
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
403 PM EDT WED JUN 12 2013
.SYNOPSIS...
A WARM FRONT WILL BECOME NEARLY STATIONARY ACROSS NORTHERN OHIO AND
NORTHERN PENNSYLVANIA THROUGH THURSDAY MORNING AS LOW PRESSURE MOVES
EAST ALONG THE FRONT. HIGH PRESSURE WILL BUILD SOUTH ACROSS THE AREA
BY SATURDAY MORNING AND TO THE CAROLINA COAST BY SATURDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THE WAITING GAME BEGINS. SO FAR ATMOSPHERE APPEARS TO BE WELL
CAPPED AND IS SUPPRESSING CONVECTION FROM DEVELOPING UPSTREAM. THE
OTHER ISSUE AT HAND IS THE EXTENSIVE DEBRIS CLOUDS HANGING AROUND.
WE NEVER CLEARED OUT OR HAD ANY BREAKS IN THE OVERCAST AS EXPECTED
AND THIS IS ALSO LIMITING ANY DEVELOPMENT OVER THE REGION.
COORDINATED WITH COFORECASTER...IT APPEARS AN AREA OF CONVERGENCE
HAS SET UP BACK OVER EASTERN IOWA AND NORTHWEST ILLINOIS AT THIS
TIME AND THIS COULD VERY WELL BE THE LOCATION THE THUNDERSTORMS
DEVELOP. LATEST HRRR MODEL SHOWS CONVECTION FIRING OVER THIS AREA AS
WELL AND HAS BEEN PRETTY CONSISTENT FROM RUN TO RUN TODAY. THERE IS
THE POSSIBILITY THAT ACTIVITY COULD DEVELOP AHEAD OF THE MAIN LINE
AS INDIVIDUAL CELLS OVERNIGHT.
LATEST SURFACE ANALYSIS SHOWS DEWPOINT TEMPERATURES RISING INTO THE
LOWER 70S INTO THE SOUTHWEST PORTION OF THE FORECAST AREA AT THIS
TIME. WE SHOULD CONTINUE TO SEE A SURGE OF THE HIGHER DEWPOINT AIR
INTO THE FORECAST AREA AS THE EVENING PROGRESSES. THIS WILL HELP TO
INCREASE THE MOISTURE ACROSS THE REGION PRIMING THE ATMOSPHERE FOR
THE POTENTIAL FOR HEAVY RAIN THAT WE HAVE BEEN EXPECTING.
THE SURGE OF STRONG STORMS WILL ENTER THE AREA AND COULD POSSIBLY
EVOLVE INTO AN OVERRUNNING SITUATION ALONG THE STATIONARY FRONT LATE
TONIGHT. THE SEVERE THREAT WILL TRANSITION INTO A POTENTIAL FLOODING
THREAT WITH LOCALLY HEAVY RAIN FROM THE THUNDERSTORMS. THUNDERSTORMS
WILL BE EFFICIENT RAIN PRODUCERS AND AREAS COULD SEE SUBSTANTIAL
PONDING OF WATER OVERNIGHT ALONG WITH THE RAPID RISES OF RIVERS AND
STREAMS. SEE HYDRO SECTION BELOW.
TROPICAL AIR MASS OVER THE REGION WILL BE ACROSS THE SOUTHERN HALF
OF THE FORECAST AREA. NORTHERN HALF OF THE AREA WILL REMAIN NORTH OF
THE STATIONARY FRONT MOST OF THE NIGHT. AS THE LOW PRESSURE SYSTEM
MOVES EAST...IT WILL PUSH THE FRONT NORTH TO THE LAKE SHORE AS A
WARM FRONT. TEMPERATURES OVERNIGHT IN THE LOWER 70S SOUTH AND UPPER
60S IN THE NORTH.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
LOW PRESSURE IS PROGGED TO PULL OUT TO THE EAST THURSDAY MORNING AS
UPPER LEVEL AMPLIFIED RIDGE BUILDS EAST FORCING UPPER LEVEL TROUGH
OFF THE COAST. AS SURFACE LOW MOVES EAST...ASSOCIATED MOISTURE AND
SUBSEQUENT PRECIPITATION WILL EXIT TO THE EAST AS WELL. HIGH
PRESSURE AT THE SURFACE PUSHES SOUTHEAST ACROSS THE AREA FORCING
DRIER AIR INTO THE REGION FOR THURSDAY NIGHT INTO FRIDAY.
THE HIGH WILL MOVE SOUTHEAST TO THE CAROLINA COAST BY SATURDAY NIGHT
AND THIS WILL SET UP ANOTHER RETURN SOUTHERLY FLOW TO THE FORECAST
AREA. A FAIRLY FAST MOVING SHORTWAVE TROUGH AND ASSOCIATED MOISTURE
WILL BEGIN TO MOVE EAST INTO THE FORECAST AREA SATURDAY INTO
SATURDAY NIGHT AND COULD BRING ANOTHER ROUND OF SHOWERS TO THE
FORECAST AREA.
COLD AIR ADVECTION ASSOCIATED WITH THE HIGH PRESSURE WILL OCCUR ON
THURSDAY BUT WILL BE SHORT LIVED AS HIGH MOVES TO THE SOUTHEAST. AS
MENTIONED EARLIER...RETURN SOUTHERLY FLOW WILL BRING TEMPERATURES
BACK UP INTO THE MIDDLE 70S EAST AND UPPER 70S TO LOWER 80S WEST BY
SATURDAY. LOWS DIPPING BACK TO THE 50S THURSDAY AND FRIDAY NIGHTS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A RIPPLE OF LOW PRESSURE WILL BE MOVING INTO THE REGION ON SUNDAY
WITH SCATTERED THUNDERSTORMS POSSIBLE...ESPECIALLY SUNDAY AFTERNOON.
THE MODELS ARE THEN STRUGGLING WITH THE TIMING OF ANOTHER WAVE THAT
MAY MOVE INTO THE CENTRAL GREAT LAKES ON MONDAY. SO AFTER A BRIEF
LULL IN THUNDERSTORM ACTIVITY LATE SUNDAY NIGHT INTO MONDAY MORNING
WE SHOULD SEE THUNDERSTORM CHANCES RETURN MONDAY AFTERNOON AND
EVENING. THERE MAY BE SOME LINGERING LIGHT SHOWERS OR THUNDERSTORMS
TUESDAY AS HIGH PRESSURE BEGINS TO BUILD INTO THE REGION LATE.
TEMPERATURES THROUGH THE EXTENDED WILL BE WITHIN A FEW DEGREES OF
SEASONAL AVERAGES.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
A WEST TO EAST ORIENTED FRONTAL BOUNDARY WILL REMAIN
QUASISTATIONARY ACROSS CENTRAL OHIO TODAY. A LOW PRESSURE
DISTURBANCE OVER NORTHERN ILLINOIS WILL MAKE ITS WAY EAST ALONG
THIS BOUNDARY TONIGHT...INITIATING THUNDERSTORMS ACROSS THE
FORECAST AREA TONIGHT INTO THURSDAY. THUNDERSTORMS MAY REACH THE
WESTERN TAF SITES SOMETIME AROUND 22Z. THERE IS A CHANCE THAT THIS
DISTURBANCE WILL BECOME FORWARD PROPAGATING...MOVING QUICKLY
THROUGH THE FORECAST AREA. IF THIS OCCURS...A SUBSTANTIAL GUST
FRONT COULD DEVELOP ALONG THE LEADING EDGE OF THE DISTURBANCE.
WILL MONITOR THE THREAT OVER THE NEXT COUPLE OF HOURS TO DETERMINE
WHETHER OR NOT TO ADD A VARIABLE WIND GUST TO TAFS FOR THE 00-04Z
TIME FRAME.
SHOWERS WILL ACCOMPANY THE THUNDERSTORMS THIS EVENING AND WILL
LIKELY PERSIST INTO THURSDAY AS A COLD FRONT MOVES INTO THE AREA.
CEILINGS WILL LOWER TO MVFR OVERNIGHT AND IFR THURSDAY MORNING. MOST
OF THE RAIN WILL OCCUR OVERNIGHT AND EARLY THURSDAY MORNING...WITH
VISIBILITIES DROPPING TO MVFR IN THE HEAVIEST SHOWERS.
CEILINGS WILL BEGIN TO LIFT AND RAIN WILL BEGIN TO CLEAR OUT EARLY
THURSDAY AFTERNOON TOWARDS THE END OF THE TAF PERIOD.
.OUTLOOK...NON VFR CONDITIONS POSSIBLE THURSDAY NIGHT AND SATURDAY
NIGHT AND SUNDAY IN SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
SCATTERED SHOWERS CONTINUE OVER LAKE ERIE THIS AFTERNOON WITH WINDS
VARYING FROM A NORTHEAST TO SOUTHEAST DIRECTION. LATER TONIGHT...A
LOW PRESSURE SYSTEM WILL MOVE EAST ALONG A QUASISTATIONARY BOUNDARY
LYING ACROSS CENTRAL OHIO. SHOWERS AND THUNDERSTORMS WILL
ACCOMPANY THE DISTURBANCE. SOME OF THE THUNDERSTORMS MAY BECOME
SEVERE...WARRANTING A SPECIAL MARINE WARNING.
SHOWERS ARE EXPECTED TO CONTINUE INTO THURSDAY AHEAD OF A COLD
FRONT. MOST OF THE SHOWERS WILL OCCUR OVERNIGHT INTO THURSDAY
MORNING. WINDS WILL INCREASE IN SPEED WITH THE PASSAGE OF THE COLD
FRONT THURSDAY NIGHT. MODELS ARE STILL A BIT UNCERTAIN WITH HOW
STRONG WINDS WILL GET...WHICH WILL AFFECT WAVE HEIGHTS. FOR NOW IT
DOES NOT APPEAR THAT A SMALL CRAFT ADVISORY WILL BE NECESSARY...BUT
THE NEXT FORECAST SHIFT WILL CONTINUE TO MONITOR THE SITUATION.
HIGH PRESSURE WILL BUILD OVER THE LAKE FRIDAY NIGHT AND MOVE EAST
LATE SATURDAY NIGHT. AS THE HIGH MOVES EAST...WINDS WILL TURN TO THE
SOUTHWEST AND PICK UP SPEED. A LOW PRESSURE SYSTEM AND ASSOCIATED
COLD FRONT WILL APPROACH THE AREA ON MONDAY.
&&
.HYDROLOGY...
A FLOOD WATCH IS IN EFFECT FOR THE ENTIRE AREA FROM THE HEAVY
RAINFALL EXPECTED OVERNIGHT AND EARLY THURSDAY. MOISTURE ADVECTION
WILL INCREASE OVER THE AREA THIS AFTERNOON AND NOTABLY OVERNIGHT AS
AN AREA OF LOW PRESSURE MOVES INTO THE REGION FROM THE WEST. THERE
IS SOME INDICATION THAT PRECIPITABLE WATER VALUES COULD REACH 2.0"
WHICH IS ANOMALOUSLY HIGH FOR THIS TIME OF YEAR. THE SHOWERS WILL BE
EFFICIENT RAIN MAKERS AND COULD DROP A QUICK INCH TO AN AREA. THE
THREAT OF TRAINING STORMS IS HIGH SUGGESTING THE THREAT OF A QUICK 2
TO 3 INCHES OF RAIN IS POSSIBLE. RAINFALL RATES THIS HIGH COULD
PRODUCE FLASH FLOODING. THE HEAVIEST RAIN WILL FALL BETWEEN 10 PM
TONIGHT AND 8 AM THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR OHZ011>014-020>023-031>033-038-089.
FLOOD WATCH THROUGH THURSDAY AFTERNOON FOR OHZ003-006>010-
017>019-027>030-036-037-047.
PA...FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR PAZ001>003.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...MULLEN
AVIATION...MULLEN/YEAGER
MARINE...MULLEN/YEAGER
HYDROLOGY...JAMISON
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1244 PM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE ALONG A FRONT STALLED OVER THE AREA TONIGHT
AND THURSDAY MORNING. HIGH PRESSURE WILL SLIDE SOUTHEAST THROUGH THE
GREAT LAKES FRIDAY THROUGH SATURDAY AND TO THE CAROLINA COAST
SUNDAY. ANOTHER LOW WILL MOVE EAST ACROSS THE LAKES SUNDAY AND
MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TEMPERATURES CONTINUE TO SURGE UPWARD AS BREAKS IN THE OVERCAST
ALLOW FOR HEATING TO TAKE PLACE AT THIS TIME. CURRENT TEMPERATURES
ARE IN THE UPPER 70S WEST AND LOWER TO MIDDLE 70S ELSEWHERE. DEW
POINT TEMPERATURES ARE ALSO CLIMBING WITH EXPECTED SURFACE VALUES
IN THE LOWER 70S WEST BY LATE THIS AFTERNOON AND UPPER 60S
ELSEWHERE. ALL IN ALL THIS SCENARIO IS SHAPING UP TO BE A VERY
MOIST ENVIRONMENT TO FEED THE CONVECTION ALONG WITH ANY
INTERACTIONS WITH THE STATIONARY FRONT IN PLACE. SIGNIFICANT
RAINFALL TOTALS STILL APPEAR LIKELY ACROSS THE AREA. WARM CLOUD
DEPTH IS FAIRLY SHALLOW THROUGH DAY AT AROUND 9000 FEET BUT
INCREASES TO OVER 12000 FEET LATER TONIGHT MAKING THUNDERSTORMS
VERY EFFICIENT RAIN PRODUCERS.
AS FAR AS SEVERE WEATHER THREAT GOES...HIGH RISK SEVERE WEATHER
REMAINS WEST OF THE FORECAST AREA BUT OUR WESTERN PORTIONS REMAIN
IN THE MODERATE RISK AND A SLIGHT RISK ELSEWHERE. THE BOTTOM
LINE IS THAT SIGNIFICANT WEATHER CAN BE EXPECTED THIS EVENING INTO
TONIGHT WITH SEVERE THREATS STILL BEING HIGH WINDS AND HAIL. STILL
CANT RULE OUT TORNADOES AS A THREAT AS WELL AS SURFACE LOW
PRESSURE MOVES EAST ACROSS THE REGION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THIS LOOKS TO BE ONE OF THE BEST SETUPS FOR A CONVECTIVE COMPLEX TO
WORK ACROSS THE CWA THAT WE`VE SEEN IN A WHILE. NOT SAYING THERE
WILL BE A DERECHO BUT THE POSSIBILITY IS THERE. TRACK OF THE CORE OF
THE CONVECTION HAS BEEN CONSISTENT FOR SEVERAL DAYS SO WILL STAY
WITH POPS 90 PERCENT OR BETTER AT SOME POINT TONIGHT INTO THU
MORNING FOR THE WHOLE CWA.
WITH P/W`S RUNNING CLOSE TO 2 INCHES FOR MOST OF THE AREA SEE NO
REASON NOT TO HAVE A FLOOD WATCH GOING. ENOUGH QPF STILL SHOWN FOR
THU MORNING TO SLOW POP DRAW DOWN SOME.
QUESTION WHETHER THINGS WILL BE ABLE TO RECOVER FROM MORNING PRECIP
AND CLOUDS TO ALLOW AIR MASS TO DESTABILIZE ENOUGH FOR SOME WIDELY
SCT AFTERNOON CONVECTION TO DEVELOP. GFS HAS BEEN CONSISTENTLY
TRYING TO REDEVELOP SOME SHRA OVER THE WEST THU AFTERNOON AS A
RESULT OF FORCING FROM PRESENCE OF UPPER TROUGH. COOLER FLOW OUT OF
THE NORTH BEHIND THE LOW THU AFTERNOON...ALONG WITH GENERAL
SUBSIDENCE AND DRIER AIR WOULD SEEM TO MAKE IT FAIRLY TOUGH TO ALLOW
FOR MUCH CONVECTION TO DEVELOP. GUIDANCE POPS FOR 18Z THRU 00Z THU
EVE VERY LOW AND THIS SEEM TO MAKE SENSE SO WILL LOWER POPS.
UPPER TROUGH SLOWS JUST EAST OF THE AREA THU NIGHT INTO FRI. WRAP
MOISTURE CONTINUES TO BE SHOWN ROTATING SOUTH ACROSS THE EASTERN
PART OF THE CWA THU NIGHT AND FRI. WILL KEEP SMALL CHANCE FOR SHRA
GOING. THINK THE SHRA SHOULD BE DONE BY FRI EVENING BUT WILL KEEP A
SLIGHT CHANCE FOR THE INLAND EAST FOR THE EARLY PART OF FRI EVE TO
GIVE ANY LINGERING CONVECTIVE SHRA A FEW HOURS TO DIE OFF.
WITH CLOUDS LIKELY TO BE OVER THE EAST THU NIGHT WILL ADJUST LOWS UP
A LITTLE MORE.
SOME HIGH CLOUDS MAY BE SPREADING INTO THE AREA LATER FRI NIGHT BUT
STILL SHOULD SEE ENOUGH CLOUD FREE TIME FOR DECENT RADIATIONAL
COOLING TO TAKE PLACE AS THE HIGH MOVES OVERHEAD. LOWS MOST PLACES
LOOK TO BE SEASONALLY COOL WITH READINGS MOSTLY DOWN INTO A 48 TO 55
RANGE.
PROGRESSIVE UPPER FLOW WILL HELP SURFACE HIGH OFF TO THE EAST BY
LATE SAT. MODELS BRING A WEAK UPPER DISTURBANCE INTO THE AREA BY SAT
EVENING. WARM FRONT LIFTING NEAR LERI WILL PROVIDE FOCUS FOR
CONVECTION TO SLIDE SE INTO THE AREA SO WILL INCREASE POP FOR SAT
AFTERNOON AND NIGHT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
A THREAT OF SHOWERS AND THUNDERSTORMS FOR MUCH OF THIS FORECAST
PERIOD. A THREAT SUNDAY AHEAD OF THE FRONT WHICH WILL MOVE ACROSS
THE AREA SUNDAY NIGHT INTO MONDAY. CONTINUING THE THREAT INTO
TUESDAY WITH AN UPPER TROF ACROSS THE REGION EVEN THOUGH HIGH
PRESSURE IS BUILDING IN AT THE SURFACE. THAT MEANS IT MAY BE MORE
DIURNAL IN NATURE. WENT CLOSE TO WPC FOR THE TEMPERATURE FORECAST.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE OVER THE AREA WITH A DIFFUSE STATIONARY BOUNDARY
WEST TO EAST ACROSS CENTRAL OHIO. THE MORNING ISSUES ARE SOME
PATCHY FOG ACROSS THE FORECAST AREA AND STRATUS FOR NW PA. THEY
WILL BOTH BURN OFF OR RAISE SOMEWHAT RAPIDLY THIS MORNING. SOME
SHOWERS ARE OVER NORTHWEST OHIO AND I AM GOING WITH THEY WILL
DISSIPATE AS THEY MOVE EAST.
OTHERWISE THE ISSUE IS THE TIMING AND STRENGTH OF THE
THUNDERSTORMS FOR THE LATE AFTERNOON AND EVENING. MANY MODELS
INDICATE THE SHOWERS AND THUNDERSTORMS WON`T GET GOING UNTIL AFTER
DARK...WHILE THE HRRR AND THE RUC/RAP STARTS THE SHOWERS AND
THUNDERSTORMS AFTER 21Z. ON THE EDGE ABOUT THAT...TRIED TO LEAN
TOWARD THE MOST SIGNIFICANT SHOWERS AND THUNDERSTORMS OCCURRING DURING
THE OVERNIGHT HOURS AS THE SURFACE LOW MOVES ALONG THE BOUNDARY.
IT SHOULD BE SEVERAL WAVES OF PRECIPITATION. OCCASIONAL
IFR...MAINLY IN THE VISIBILITY AND EVENTUALLY AFTER THE SURFACE
LOW MOVES EAST IFR CEILINGS IN THE NORTHERLY FLOW. WIDESPREAD
STRONG WINDS COULD BE ASSOCIATED WITH THE THUNDERSTORMS IF THEY
FORM A LINE. ALL THIS WILL HAVE TO BE MONITORED.
.OUTLOOK...NON VFR CONDITIONS THURSDAY AND POSSIBLY CONTINUING INTO
THURSDAY NIGHT AND SATURDAY NIGHT AND SUNDAY IN SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
HIGH PRESSURE OVER THE AREA TO START WITH A STATIONARY FRONT WELL
SOUTH OF LAKE ERIE. A LOW WILL MOVE ALONG THE FRONT AND THAT WILL
INCREASE THE WINDS TONIGHT AND THURSDAY...IN THE MEANTIME THE WINDS
WILL BE LIGHT AND VARIABLE. SOME QUESTION HOW CLOSE THE LOW WILL
TRACK TO THE LAKE...WENT MORE WITH THE GFS WHICH TRACKS THE LOW A
LITTLE FARTHER FROM THE LAKE SO THE WINDS MAY BE STRONGER. A SMALL
CRAFT ADVISORY MAY BE NEEDED BY DAYBREAK THURSDAY AND THE THREAT
WILL CONTINUE INTO THURSDAY NIGHT. SPECIAL MARINE WARNINGS MAY BE
NEEDED MAINLY THIS EVENING AND TONIGHT FOR LAKE ERIE.
HIGH PRESSURE WILL BUILD OVER LAKE ERIE FRIDAY NIGHT AND MOVE EAST
SATURDAY NIGHT ALLOWING A SOUTHWEST FLOW TO DEVELOP. THE FLOW WILL
BE STRONG AND THAT MAY CAUSE WAVES TO BE 2 TO 4 FEET ON THE EAST END
OF THE LAKE. OTHERWISE THE NEXT SIGNIFICANT THREAT FOR A SMALL CRAFT
ADVISORY WILL BE EARLY NEXT WEEK WHEN A COLD FRONT MOVES ACROSS THE
AREA.
&&
.HYDROLOGY...
A FLOOD WATCH IS IN EFFECT FOR THE ENTIRE AREA FROM THE HEAVY
RAINFALL EXPECTED OVERNIGHT AND EARLY THURSDAY. MOISTURE ADVECTION
WILL INCREASE OVER THE AREA THIS AFTERNOON AND NOTABLY OVERNIGHT AS
AN AREA OF LOW PRESSURE MOVES INTO THE REGION FROM THE WEST. THERE
IS SOME INDICATION THAT PRECIPITABLE WATER VALUES COULD REACH 2.0"
WHICH IS ANOMALOUSLY HIGH FOR THIS TIME OF YEAR. THE SHOWERS WILL BE
EFFICIENT RAIN MAKERS AND COULD DROP A QUICK INCH TO AN AREA. THE
THREAT OF TRAINING STORMS IS HIGH SUGGESTING THE THREAT OF A QUICK 2
TO 3 INCHES OF RAIN IS POSSIBLE. RAINFALL RATES THIS HIGH COULD
PRODUCE FLASH FLOODING. THE HEAVIEST RAIN WILL FALL BETWEEN 10 PM
TONIGHT AND 8 AM THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR OHZ011>014-020>023-031>033-038-089.
FLOOD WATCH FROM 6 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR OHZ003-006>010-017>019-027>030-036-037-047.
PA...FLOOD WATCH FROM 10 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR PAZ001>003.
MARINE...NONE.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...LOMBARDY
SHORT TERM...ADAMS
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
HYDROLOGY...JAMISON
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1000 AM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE ALONG A FRONT STALLED OVER THE AREA TONIGHT
AND THURSDAY MORNING. HIGH PRESSURE WILL SLIDE SOUTHEAST THROUGH THE
GREAT LAKES FRIDAY THROUGH SATURDAY AND TO THE CAROLINA COAST
SUNDAY. ANOTHER LOW WILL MOVE EAST ACROSS THE LAKES SUNDAY AND
MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST SATELLITE SHOWS A LOT OF DEBRIS CLOUDS MOVING EAST INTO THE
FORECAST AREA THIS MORNING. SO FAR...MODELS ARE HINTING AT THIS
CLOUD MASS ERODING FROM THE SOUTH AS TIME GOES ON. SO...WE SHOULD
HAVE A FAIR AMOUNT OF SUNSHINE RETURN THIS AFTERNOON TO HELP WITH
CONVECTIVE INITIATION FOR THE AFTERNOON INTO THE EVENING HOURS.
IT LOOKS LIKE THE BRUNT OF THE STORMS WILL DEVELOP AND AFFECT THE
AREA LATE THIS AFTERNOON INTO THE EVENING HOURS. BEST UPPER LEVEL
POSITIVE VORTICITY ADVECTION AND VORTICITY MAXIMUM SCOOTS ACROSS
LAKE ERIE AROUND 21Z THIS AFTERNOON AND THEN THE NEXT MORE POTENT
UPPER LEVEL VORTICITY MAXIMUM ARRIVES LATE THIS EVENING INTO
TONIGHT. PRECIPITABLE WATER VALUES ARE NOW APPROACHING 2 INCHES
AND WITH DEEP WARM LAYER...SIGNIFICANT RAINFALL IS
EXPECTED...ESPECIALLY IN TRAINING THUNDERSTORMS.
SEVERE WEATHER THREAT IS STILL LIKELY WITH WIND...HAIL AND
POSSIBLY TORNADOES BEING THE THREATS FOR THIS AFTERNOON INTO
TONIGHT. WILL CONTINUE TO MONITOR THE SITUATION AS IT DEVELOPS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THIS LOOKS TO BE ONE OF THE BEST SETUPS FOR A CONVECTIVE COMPLEX TO
WORK ACROSS THE CWA THAT WE`VE SEEN IN A WHILE. NOT SAYING THERE
WILL BE A DERECHO BUT THE POSSIBILITY IS THERE. TRACK OF THE CORE OF
THE CONVECTION HAS BEEN CONSISTENT FOR SEVERAL DAYS SO WILL STAY
WITH POPS 90 PERCENT OR BETTER AT SOME POINT TONIGHT INTO THU
MORNING FOR THE WHOLE CWA.
WITH P/W`S RUNNING CLOSE TO 2 INCHES FOR MOST OF THE AREA SEE NO
REASON NOT TO HAVE A FLOOD WATCH GOING. ENOUGH QPF STILL SHOWN FOR
THU MORNING TO SLOW POP DRAW DOWN SOME.
QUESTION WHETHER THINGS WILL BE ABLE TO RECOVER FROM MORNING PRECIP
AND CLOUDS TO ALLOW AIRMASS TO DESTABILIZE ENOUGH FOR SOME WIDELY
SCT AFTERNOON CONVECTION TO DEVELOP. GFS HAS BEEN CONSISTENTLY
TRYING TO REDEVELOP SOME SHRA OVER THE WEST THU AFTERNOON AS A
RESULT OF FORCING FROM PRESENCE OF UPPER TROUGH. COOLER FLOW OUT OF
THE NORTH BEHIND THE LOW THU AFTERNOON...ALONG WITH GENERAL
SUBSIDENCE AND DRIER AIR WOULD SEEM TO MAKE IT FAIRLY TOUGH TO ALLOW
FOR MUCH CONVECTION TO DEVELOP. GUIDANCE POPS FOR 18Z THRU 00Z THU
EVE VERY LOW AND THIS SEEM TO MAKE SENSE SO WILL LOWER POPS.
UPPER TROUGH SLOWS JUST EAST OF THE AREA THU NIGHT INTO FRI. WRAP
MOISTURE CONTINUES TO BE SHOWN ROTATING SOUTH ACROSS THE EASTERN
PART OF THE CWA THU NIGHT AND FRI. WILL KEEP SMALL CHANCE FOR SHRA
GOING. THINK THE SHRA SHOULD BE DONE BY FRI EVENING BUT WILL KEEP A
SLIGHT CHANCE FOR THE INLAND EAST FOR THE EARLY PART OF FRI EVE TO
GIVE ANY LINGERING CONVECTIVE SHRA A FEW HOURS TO DIE OFF.
WITH CLOUDS LIKELY TO BE OVER THE EAST THU NIGHT WILL ADJUST LOWS UP
A LITTLE MORE.
SOME HIGH CLOUDS MAY BE SPREADING INTO THE AREA LATER FRI NIGHT BUT
STILL SHOULD SEE ENOUGH CLOUD FREE TIME FOR DECENT RADIATIONAL
COOLING TO TAKE PLACE AS THE HIGH MOVES OVERHEAD. LOWS MOST PLACES
LOOK TO BE SEASONALLY COOL WITH READINGS MOSTLY DOWN INTO A 48 TO 55
RANGE.
PROGRESSIVE UPPER FLOW WILL HELP SURFACE HIGH OFF TO THE EAST BY
LATE SAT. MODELS BRING A WEAK UPPER DISTURBANCE INTO THE AREA BY SAT
EVENING. WARM FRONT LIFTING NEAR LERI WILL PROVIDE FOCUS FOR
CONVECTION TO SLIDE SE INTO THE AREA SO WILL INCREASE POP FOR SAT
AFTERNOON AND NIGHT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
A THREAT OF SHOWERS AND THUNDERSTORMS FOR MUCH OF THIS FORECAST
PERIOD. A THREAT SUNDAY AHEAD OF THE FRONT WHICH WILL MOVE ACROSS
THE AREA SUNDAY NIGHT INTO MONDAY. CONTINUING THE THREAT INTO
TUESDAY WITH AN UPPER TROF ACROSS THE REGION EVEN THOUGH HIGH
PRESSURE IS BUILDING IN AT THE SURFACE. THAT MEANS IT MAY BE MORE
DIURNAL IN NATURE. WENT CLOSE TO WPC FOR THE TEMPERATURE FORECAST.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE OVER THE AREA WITH A DIFFUSE STATIONARY BOUNDARY
WEST TO EAST ACROSS CENTRAL OHIO. THE MORNING ISSUES ARE SOME
PATCHY FOG ACROSS THE FORECAST AREA AND STRATUS FOR NW PA. THEY
WILL BOTH BURN OFF OR RAISE SOMEWHAT RAPIDLY THIS MORNING. SOME
SHOWERS ARE OVER NORTHWEST OHIO AND I AM GOING WITH THEY WILL
DISSIPATE AS THEY MOVE EAST.
OTHERWISE THE ISSUE IS THE TIMING AND STRENGTH OF THE
THUNDERSTORMS FOR THE LATE AFTERNOON AND EVENING. MANY MODELS
INDICATE THE SHOWERS AND THUNDERSTORMS WON`T GET GOING UNTIL AFTER
DARK...WHILE THE HRRR AND THE RUC/RAP STARTS THE SHOWERS AND
THUNDERSTORMS AFTER 21Z. ON THE EDGE ABOUT THAT...TRIED TO LEAN
TOWARD THE MOST SIGNIFICANT SHOWERS AND THUNDERSTORMS OCCURRING DURING
THE OVERNIGHT HOURS AS THE SURFACE LOW MOVES ALONG THE BOUNDARY.
IT SHOULD BE SEVERAL WAVES OF PRECIPITATION. OCCASIONAL
IFR...MAINLY IN THE VISIBILITY AND EVENTUALLY AFTER THE SURFACE
LOW MOVES EAST IFR CEILINGS IN THE NORTHERLY FLOW. WIDESPREAD
STRONG WINDS COULD BE ASSOCIATED WITH THE THUNDERSTORMS IF THEY
FORM A LINE. ALL THIS WILL HAVE TO BE MONITORED.
.OUTLOOK...NON VFR CONDITIONS THURSDAY AND POSSIBLY CONTINUING INTO
THURSDAY NIGHT AND SATURDAY NIGHT AND SUNDAY IN SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
HIGH PRESSURE OVER THE AREA TO START WITH A STATIONARY FRONT WELL
SOUTH OF LAKE ERIE. A LOW WILL MOVE ALONG THE FRONT AND THAT WILL
INCREASE THE WINDS TONIGHT AND THURSDAY...IN THE MEANTIME THE WINDS
WILL BE LIGHT AND VARIABLE. SOME QUESTION HOW CLOSE THE LOW WILL
TRACK TO THE LAKE...WENT MORE WITH THE GFS WHICH TRACKS THE LOW A
LITTLE FARTHER FROM THE LAKE SO THE WINDS MAY BE STRONGER. A SMALL
CRAFT ADVISORY MAY BE NEEDED BY DAYBREAK THURSDAY AND THE THREAT
WILL CONTINUE INTO THURSDAY NIGHT. SPECIAL MARINE WARNINGS MAY BE
NEEDED MAINLY THIS EVENING AND TONIGHT FOR LAKE ERIE.
HIGH PRESSURE WILL BUILD OVER LAKE ERIE FRIDAY NIGHT AND MOVE EAST
SATURDAY NIGHT ALLOWING A SOUTHWEST FLOW TO DEVELOP. THE FLOW WILL
BE STRONG AND THAT MAY CAUSE WAVES TO BE 2 TO 4 FEET ON THE EAST END
OF THE LAKE. OTHERWISE THE NEXT SIGNIFICANT THREAT FOR A SMALL CRAFT
ADVISORY WILL BE EARLY NEXT WEEK WHEN A COLD FRONT MOVES ACROSS THE
AREA.
&&
.HYDROLOGY...
THE FLOOD THREAT WILL INCREASE WEDNESDAY EVENING INTO THURSDAY
MORNING AS A WARM FRONT AND A DEEPENING LOW MOVE INTO NORTHERN OHIO.
BROAD UPPER LVL DIFFLUENCE AND DEEP SOUTHERLY FLOW AHEAD OF THE
SURFACE LOW WILL SET THE STAGE FOR SOME EFFICIENT RAIN. PRECIPITABLE
WATER VALUES WILL RISE TO 1.6-2.0" AND WITH STORM FORWARD SPEEDS
EXPECTED TO SLOW INTO THE OVERNIGHT HOURS...THERE IS A HIGH THREAT
OF TRAINING STORMS WITH HEAVY RAIN. ON AVERAGE...MUCH OF THE AREA
CAN SEE 1.5 TO 3 INCHES OF RAINFALL FROM THIS EVENT.
THE HEAVIEST RAIN WILL FALL AFTER 8 PM WEDNESDAY THROUGH 8 AM
THURSDAY. HIGH RAINFALL RATES ON ALREADY WET GROUND WILL SUPPORT THE
DEVELOPMENT OF FLOODS. ALL RIVERS ARE AT RISK FOR FLOODING WITH THE
POTENTIAL FOR MAJOR FLOODING.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...FLOOD WATCH FROM THIS EVENING THROUGH THURSDAY AFTERNOON FOR
OHZ011>014-020>023-031>033-038-089.
FLOOD WATCH FROM 6 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR OHZ003-006>010-017>019-027>030-036-037-047.
PA...FLOOD WATCH FROM THIS EVENING THROUGH THURSDAY AFTERNOON FOR
PAZ001>003.
MARINE...NONE.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...LOMBARDY
SHORT TERM...ADAMS
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
HYDROLOGY...JAMISON/ADAMS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
745 AM EDT WED JUN 12 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE ALONG A FRONT STALLED OVER THE AREA TONIGHT
AND THURSDAY MORNING. HIGH PRESSURE WILL SLIDE SOUTHEAST THROUGH THE
GREAT LAKES FRIDAY THROUGH SATURDAY AND TO THE CAROLINA COAST
SUNDAY. ANOTHER LOW WILL MOVE EAST ACROSS THE LAKES SUNDAY AND
MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FOR EARLY MORNING UPDATE...LATEST SHORT TERM MODEL RUNS ALL OVER THE
PLACE WITH QPF THRU MID AFTERNOON SO NOT CONFIDENT IN ANY OF THIS
NEW INFORMATION. CURRENT REGIONAL RADAR SHOWS MOST OF THE SHRA OVER
THE EASTERN PART OF THE CWA HAVE MOVED OFF TO THE SE WHILE BAND OF
LIGHT SHRA HAS CONTINUED TO PUSH SE ACROSS LWR MI INTO EXTREME NW
CORNER OF OH. WILL ALLOW FOR THIS BAND TO MAKE SLOW EASTWARD
PROGRESS THRU EARLY AFTERNOON BUT NOT QUITE AS FAST AS HRRR. THUS
CHC POPS SPREAD INTO CLE AND CAK AREA BY NOON.
THE INGREDIENTS ARE STILL LOOKING TO COME TOGETHER TODAY INTO
TONIGHT FOR STRONG TO SEVERE STORMS TO SPREAD ACROSS THE AREA.
WITH A WEAK FRONT STALLED OVER THE CWA THERE SHOULD BE A GOOD TEMP
GRADIENT WITH TODAY HIGHS WHICH SHOULD RANGE FROM THE MID 70S IN THE
FAR NE LAKESHORE TO THE MID TO UPPER 80S IN THE EXTREME SW.
QUESTION TODAY IS HOW MUCH CONVECTION WILL GET GOING AND HOW
QUICKLY. LATEST NAM RUN BARELY PRODUCES A TENTH OF AN INCH OF QPF
NEAR THE FDY AREA WITH LESSER AMOUNTS OVER THE REST OF THE CWA.
FLOOD WATCH FOR TONIGHT INTO THU MORNING SET TO START IN THE WEST AT
22Z THIS EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THIS LOOKS TO BE ONE OF THE BEST SETUPS FOR A CONVECTIVE COMPLEX TO
WORK ACROSS THE CWA THAT WE`VE SEEN IN A WHILE. NOT SAYING THERE
WILL BE A DERECHO BUT THE POSSIBILITY IS THERE. TRACK OF THE CORE OF
THE CONVECTION HAS BEEN CONSISTENT FOR SEVERAL DAYS SO WILL STAY
WITH POPS 90 PERCENT OR BETTER AT SOME POINT TONIGHT INTO THU
MORNING FOR THE WHOLE CWA.
WITH P/W`S RUNNING CLOSE TO 2 INCHES FOR MOST OF THE AREA SEE NO
REASON NOT TO HAVE A FLOOD WATCH GOING. ENOUGH QPF STILL SHOWN FOR
THU MORNING TO SLOW POP DRAW DOWN SOME.
QUESTION WHETHER THINGS WILL BE ABLE TO RECOVER FROM MORNING PRECIP
AND CLOUDS TO ALLOW AIRMASS TO DESTABILIZE ENOUGH FOR SOME WIDELY
SCT AFTERNOON CONVECTION TO DEVELOP. GFS HAS BEEN CONSISTENTLY
TRYING TO REDEVELOP SOME SHRA OVER THE WEST THU AFTERNOON AS A
RESULT OF FORCING FROM PRESENCE OF UPPER TROUGH. COOLER FLOW OUT OF
THE NORTH BEHIND THE LOW THU AFTERNOON...ALONG WITH GENERAL
SUBSIDENCE AND DRIER AIR WOULD SEEM TO MAKE IT FAIRLY TOUGH TO ALLOW
FOR MUCH CONVECTION TO DEVELOP. GUIDANCE POPS FOR 18Z THRU 00Z THU
EVE VERY LOW AND THIS SEEM TO MAKE SENSE SO WILL LOWER POPS.
UPPER TROUGH SLOWS JUST EAST OF THE AREA THU NIGHT INTO FRI. WRAP
MOISTURE CONTINUES TO BE SHOWN ROTATING SOUTH ACROSS THE EASTERN
PART OF THE CWA THU NIGHT AND FRI. WILL KEEP SMALL CHANCE FOR SHRA
GOING. THINK THE SHRA SHOULD BE DONE BY FRI EVENING BUT WILL KEEP A
SLIGHT CHANCE FOR THE INLAND EAST FOR THE EARLY PART OF FRI EVE TO
GIVE ANY LINGERING CONVECTIVE SHRA A FEW HOURS TO DIE OFF.
WITH CLOUDS LIKELY TO BE OVER THE EAST THU NIGHT WILL ADJUST LOWS UP
A LITTLE MORE.
SOME HIGH CLOUDS MAY BE SPREADING INTO THE AREA LATER FRI NIGHT BUT
STILL SHOULD SEE ENOUGH CLOUD FREE TIME FOR DECENT RADIATIONAL
COOLING TO TAKE PLACE AS THE HIGH MOVES OVERHEAD. LOWS MOST PLACES
LOOK TO BE SEASONALLY COOL WITH READINGS MOSTLY DOWN INTO A 48 TO 55
RANGE.
PROGRESSIVE UPPER FLOW WILL HELP SURFACE HIGH OFF TO THE EAST BY
LATE SAT. MODELS BRING A WEAK UPPER DISTURBANCE INTO THE AREA BY SAT
EVENING. WARM FRONT LIFTING NEAR LERI WILL PROVIDE FOCUS FOR
CONVECTION TO SLIDE SE INTO THE AREA SO WILL INCREASE POP FOR SAT
AFTERNOON AND NIGHT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
A THREAT OF SHOWERS AND THUNDERSTORMS FOR MUCH OF THIS FORECAST
PERIOD. A THREAT SUNDAY AHEAD OF THE FRONT WHICH WILL MOVE ACROSS
THE AREA SUNDAY NIGHT INTO MONDAY. CONTINUING THE THREAT INTO
TUESDAY WITH AN UPPER TROF ACROSS THE REGION EVEN THOUGH HIGH
PRESSURE IS BUILDING IN AT THE SURFACE. THAT MEANS IT MAY BE MORE
DIURNAL IN NATURE. WENT CLOSE TO WPC FOR THE TEMPERATURE FORECAST.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE OVER THE AREA WITH A DIFFUSE STATIONARY BOUNDARY
WEST TO EAST ACROSS CENTRAL OHIO. THE MORNING ISSUES ARE SOME
PATCHY FOG ACROSS THE FORECAST AREA AND STRATUS FOR NW PA. THEY
WILL BOTH BURN OFF OR RAISE SOMEWHAT RAPIDLY THIS MORNING. SOME
SHOWERS ARE OVER NORTHWEST OHIO AND I AM GOING WITH THEY WILL
DISSIPATE AS THEY MOVE EAST.
OTHERWISE THE ISSUE IS THE TIMING AND STRENGTH OF THE
THUNDERSTORMS FOR THE LATE AFTERNOON AND EVENING. MANY MODELS
INDICATE THE SHOWERS AND THUNDERSTORMS WON`T GET GOING UNTIL AFTER
DARK...WHILE THE HRRR AND THE RUC/RAP STARTS THE SHOWERS AND
THUNDERSTORMS AFTER 21Z. ON THE EDGE ABOUT THAT...TRIED TO LEAN
TOWARD THE MOST SIGNIFICANT SHOWERS AND THUNDERSTORMS OCCURRING DURING
THE OVERNIGHT HOURS AS THE SURFACE LOW MOVES ALONG THE BOUNDARY.
IT SHOULD BE SEVERAL WAVES OF PRECIPITATION. OCCASIONAL
IFR...MAINLY IN THE VISIBILITY AND EVENTUALLY AFTER THE SURFACE
LOW MOVES EAST IFR CEILINGS IN THE NORTHERLY FLOW. WIDESPREAD
STRONG WINDS COULD BE ASSOCIATED WITH THE THUNDERSTORMS IF THEY
FORM A LINE. ALL THIS WILL HAVE TO BE MONITORED.
.OUTLOOK...NON VFR CONDITIONS THURSDAY AND POSSIBLY CONTINUING INTO
THURSDAY NIGHT AND SATURDAY NIGHT AND SUNDAY IN SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
HIGH PRESSURE OVER THE AREA TO START WITH A STATIONARY FRONT WELL
SOUTH OF LAKE ERIE. A LOW WILL MOVE ALONG THE FRONT AND THAT WILL
INCREASE THE WINDS TONIGHT AND THURSDAY...IN THE MEANTIME THE WINDS
WILL BE LIGHT AND VARIABLE. SOME QUESTION HOW CLOSE THE LOW WILL
TRACK TO THE LAKE...WENT MORE WITH THE GFS WHICH TRACKS THE LOW A
LITTLE FARTHER FROM THE LAKE SO THE WINDS MAY BE STRONGER. A SMALL
CRAFT ADVISORY MAY BE NEEDED BY DAYBREAK THURSDAY AND THE THREAT
WILL CONTINUE INTO THURSDAY NIGHT. SPECIAL MARINE WARNINGS MAY BE
NEEDED MAINLY THIS EVENING AND TONIGHT FOR LAKE ERIE.
HIGH PRESSURE WILL BUILD OVER LAKE ERIE FRIDAY NIGHT AND MOVE EAST
SATURDAY NIGHT ALLOWING A SOUTHWEST FLOW TO DEVELOP. THE FLOW WILL
BE STRONG AND THAT MAY CAUSE WAVES TO BE 2 TO 4 FEET ON THE EAST END
OF THE LAKE. OTHERWISE THE NEXT SIGNIFICANT THREAT FOR A SMALL CRAFT
ADVISORY WILL BE EARLY NEXT WEEK WHEN A COLD FRONT MOVES ACROSS THE
AREA.
&&
.HYDROLOGY...
THE FLOOD THREAT WILL INCREASE WEDNESDAY EVENING INTO THURSDAY
MORNING AS A WARM FRONT AND A DEEPENING LOW MOVE INTO NORTHERN OHIO.
BROAD UPPER LVL DIFFLUENCE AND DEEP SOUTHERLY FLOW AHEAD OF THE
SURFACE LOW WILL SET THE STAGE FOR SOME EFFICIENT RAIN. PRECIPITABLE
WATER VALUES WILL RISE TO 1.6-2.0" AND WITH STORM FORWARD SPEEDS
EXPECTED TO SLOW INTO THE OVERNIGHT HOURS...THERE IS A HIGH THREAT
OF TRAINING STORMS WITH HEAVY RAIN. ON AVERAGE...MUCH OF THE AREA
CAN SEE 1.5 TO 3 INCHES OF RAINFALL FROM THIS EVENT.
THE HEAVIEST RAIN WILL FALL AFTER 8 PM WEDNESDAY THROUGH 8 AM
THURSDAY. HIGH RAINFALL RATES ON ALREADY WET GROUND WILL SUPPORT THE
DEVELOPMENT OF FLOODS. ALL RIVERS ARE AT RISK FOR FLOODING WITH THE
POTENTIAL FOR MAJOR FLOODING.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...FLOOD WATCH FROM THIS EVENING THROUGH THURSDAY AFTERNOON FOR
OHZ011>014-020>023-031>033-038-089.
FLOOD WATCH FROM 6 PM EDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR OHZ003-006>010-017>019-027>030-036-037-047.
PA...FLOOD WATCH FROM THIS EVENING THROUGH THURSDAY AFTERNOON FOR
PAZ001>003.
MARINE...NONE.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...ADAMS
SHORT TERM...ADAMS
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
HYDROLOGY...JAMISON/ADAMS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
144 AM EDT WED JUN 12 2013
.SYNOPSIS...
A WEAK DISTURBANCE WILL MOVE THROUGH TONIGHT BRINGING SOME
THUNDERSTORMS TO THE AREA. STRONG LOW PRESSURE CONTAINING COPIOUS
MOISTURE WILL BRING THUNDERSTORMS WEDNESDAY INTO THURSDAY. HIGH
PRESSURE AND DRY AIR WILL ARRIVE ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CONVECTION THAT DEVELOPED OVER NRN IL AND INDIANA AND DROPPED
INTO THE FA IS QUICKLY MOVG SE AND ALSO WEAKENING. LATEST RAP AND
HRRR RUNS ARE NOW DELAYING ADDITIONAL OVERNIGHT CONVECTION UNTIL
AROUND 09Z...SO LOWERED THE POPS UNTIL THEN. THE CONVECTION ALSO
LOOKS A LITTLE MORE SCATTERED...SO LOWER POPS TONIGHT.
OVERNIGHT LOWS WILL NOT DROP TOO MUCH...ONLY FALLING INTO THE
UPPER 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
LOW PRESSURE WILL BE MOVING FROM THE GREAT PLAINS TO THE
MISSISSIPPI VALLEY DURING THE DAY ON WEDNESDAY. A WARM FRONT WILL
EXTEND FROM THE LOW ACROSS NORTHERN OHIO...LEAVING THE ILN AREA IN
THE WARM SECTOR OF THE LOW. NUMEROUS THUNDERSTORMS ARE EXPECTED TO
DEVELOP BY WEDNESDAY AFTERNOON IN FAR NORTHERN COUNTIES CLOSE TO
THE BOUNDARY...WITH SCATTERED TO ISOLATED STORMS FARTHER SOUTH
WHERE A CAP IS EXPECTED TO INHIBIT CONVECTION. IN AN ENVIRONMENT
OF MODERATE INSTABILITY AND SHEAR...SEVERE THUNDERSTORMS WILL BE
POSSIBLE WEDNESDAY AFTERNOON. HIGH TEMPERATURES AROUND 90
COMBINING WITH DEW POINTS NEAR 70 WILL RESULT IN HEAT INDICES NEAR 95.
THE LOW WILL BE TRAVELING ACROSS NORTHERN INDIANA TO NORTHWEST
OHIO WEDNESDAY NIGHT...SUPPORTED BY AN UPPER TROUGH. THIS SCENARIO
WILL BRING THUNDERSTORMS TO MOST IF NOT ALL OF THE AREA BY
THURSDAY MORNING. THE THUNDERSTORMS WILL HAVE A GOOD AMOUNT OF
INSTABILITY TO TAP INTO...AND STRONG WIND FIELDS INCLUDING A 50
KNOT LOW LEVEL JET WILL AID IN STORM ORGANIZATION. DAMAGING WIND
GUSTS AND LARGE HAIL ARE EXPECTED WITH SOME OF THE THUNDERSTORMS.
WITH MODELS SHOWING FAVORABLE HELICITY PROFILES...ISOLATED
TORNADOES WILL ALSO BE POSSIBLE. HEAVY RAIN IS ALSO VERY LIKELY IN
A REGIME OF COPIOUS MOISTURE...ESPECIALLY TOWARD THURSDAY MORNING
WHEN THUNDERSTORMS CELLS AND LINE SEGMENTS MAY MERGE INTO A LARGE
THUNDERSTORM COMPLEX.
THUNDERSTORMS WILL DIMINISH THURSDAY AS THE LOW MOVES EAST. HIGH
PRESSURE AND DRIER AIR WILL START TO BUILD IN THURSDAY NIGHT.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
HIGH PRESSURE WILL BE BUILDING INTO THE REGION FRIDAY AND KEEP A
COOLER THAN NORMAL AIRMASS OVER US FRIDAY AND FRIDAY NIGHT. FLOW
WILL TURN BACK SOUTHERLY AND REMAIN THAT WAY THROUGH THE REMAINDER
OF THE PERIOD. IT WILL WARM UP DAYTIME HIGHS BACK INTO THE UPPER 70S
AND MORE NORMAL LOWER 80S. NIGHTTIME LOWS WILL RISE TO NORMAL
SATURDAY NIGHT AND THEN THE INCREASED MOISTURE WILL BUMP THAT INTO
THE MID AND UPPER 60S SUNDAY NIGHT UNTIL SHOWERS AND THUNDERSTORMS
COOL OFF THE REGION.
THE NEXT THREAT FOR RAIN WILL BEGIN ON SUNDAY BUT THIS APPEARS TO BE
A REACTION TO THE INCREASED MOISTURE STREAMING IN ON THE SOUTHERLY
FLOW. UPPER LEVEL MAN RIDGE IS STILL WEST OF THE REGION BUT APPEARS
FLATTENED AND MODELS ARE SHOWING IMPULSES RIDING EAST-SOUTHEAST
ALONG IT TO HELP KICK OFF STORMS ON SUNDAY...PARTICULARLY ALONG AND
NORTH OF I-70. BY THE TIME SUNDAY NIGHT AND MONDAY ROLLS IN...A MORE
ORGANIZED UPPER TROUGH WILL HAVE PUSHED THE MEAN RIDGE BACK TO THE
GULF STATES AND THUNDERSTORMS WILL BE MORE LIKELY WITH A FRONTAL
PASSAGE. ACTIVE WEATHER MAY OCCUR UNTIL THE FRONT FULLY CROSSES THE
REGION EARLY TUESDAY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
CONSIDERABLE UNCERTAINTY REGARDING DEVELOPMENT OF CONVECTION
THROUGHOUT THE TAF PERIOD. BUT OUTSIDE OF ANY STORMS EXPECT VFR
CONDITIONS TO PREVAIL.
THERE CONTINUE TO BE INDICATIONS THAT ELEVATED SHOWERS OR
THUNDERSTORMS MAY DEVELOP OVER THE NEXT SEVERAL HOURS. BUT
CONFIDENCE IS NOT TOO HIGH WITH THIS POTENTIAL. SO HAVE INCLUDED
VCSH FOR INITIAL ISSUANCE AND WILL CONTINUE TO MONITOR CLOSELY.
DURING THEY DAYTIME IT APPEARS MORE LIKELY THAT STORMS WILL BE
SUPPRESSED ALTHOUGH CANNOT COMPLETELY RULE OUT SOME ACTIVITY
ESPECIALLY IN CENTRAL OHIO LATE IN THE DAY. MUCH BETTER CHANCE OF
STORMS WILL COME LATE IN THE TAF PERIOD. WITH TIMING A QUESTION
ESPECIALLY THAT FAR OUT IN TIME HAVE ONLY GONE WITH VCTS. BETTER
CHANCE MAY COME JUST BEYOND THE TAF PERIOD. THESE STORMS WILL HAVE
THE POTENTIAL TO PRODUCE VERY STRONG STRAIGHT LINE WINDS.
OUTLOOK...THUNDERSTORMS EXPECTED LATE WEDNESDAY NIGHT INTO
THURSDAY MORNING. SOME OF THESE COULD CONTAIN STRONG WIND GUSTS.
MVFR CEILINGS LIKELY THURSDAY. ADDITIONAL THUNDERSTORMS POSSIBLE
SUNDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...SITES
SHORT TERM...CONIGLIO
LONG TERM...FRANKS
AVIATION...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
802 PM EDT THU JUN 13 2013
.SYNOPSIS...
PENNSYLVANIA IS SLOWLY GETTING INTO THE NORTHWEST FLOW ON THE WEST SIDE
OF THE TROUGH WHICH BROUGHT THE THUNDERSTORMS. COOLER DRIER AIR
IS SLOWLY WORKING INTO THE REGION. THE WEATHER WILL GRADUALLY GET
QUITE PLEASANT AS THIS SYSTEM SHIFTS FARTHER EAST OVER THE NEXT 36
HOURS. A WEAK TROUGH IS FORECAST TO DOMINATE THE PATTERN OVER THE
EASTERN UNITED STATES WELL INTO NEXT WEEK. THE NORTHWEST FLOW HAS THE
POTENTIAL FOR PERIODS OF RAIN/SHOWERS BUT NO BIG WEATHER SYSTEMS CURRENTLY
FORECAST FOR A WHILE. THERE ARE HINTS OF A RIDGE MOVING IN FROM
THE WEST LATE NEXT WEEK.
&&
.NEAR TERM /UNTIL 7 AM FRIDAY MORNING/...
WINDS HAVE GONE NORTHWEST BUT LOW CLOUDS HANGING TOUGH. OVER THE
SUSQUEHANNA VALLEY WEAK RETURNS ON RADAR CONTINUE TO SHOW AREAS
LIGHT RAIN SHOWERS. THE RUC13 SHOWS A WEAK THETA-E RIDGE STUCK IN
THAT REGION...LINING UP WELL WITH THE AREA OF LIGHT RAIN SHOWERS.
THE RUC13 FORECASTS THIS AREA TO SLOWLY SAG BOTH SOUTH AND EAST
AND IT SHOULD BE GONE (IF YOU BELIEVE THE FORECASTS) BY 0400 UTC.
SO KEPT AT LEAST CHANCE POPS WITH THIS FEATURE UNTIL ABOUT THAT
TIME. VERY LIGHT AND SPOTTY RAINFALL.
IN CENTRAL AREAS IT LOOKS LIKE A NICE AUTUMN EVENING WITH ALL THE
FLAT POST FRONTAL/TROUGH ALOFT STRATOCUMULUS. A FEW SPRINKLES
COULD FALL OUT OF THESE. NOTHING OF NOTE. BREAKING UP IS HARD TO
DO SO THESE CLOUDS WILL BE WITH US OVER MOST OF THE OVERNIGHT
PERIOD.
TO THE WEST...THERE IS A WRAP-AROUND BAND OF SHOWERS AND CLOUDS OVER
WESTERN PA. SOME OF THE MESO-SCALE MODELS NOW TRY TO REPLICATE
THIS FEATURE. FOLLOWING KPBZ TRIED TO SHOW THIS BAND WEAKENING AND MOVING
TO EAST. SOME LIGHT SHOWERS OVER WARREN COUNTY AND GAVE HINT INTO
CAMBRIA EARLY OVERNIGHT WITH THIS. SOME RUC13 AND HRRR RUNS SEEM
TO SHOW THIS EVOLUTION TOO. VERY LIGHT RAIN SHOWERS WITH THIS FEATURE.
MOST AREAS SHOULD BE RAIN FREE AND TEMPS SHOULD FALL OFF BY
SUNRISE TO QUITE COMFORTABLE LEVELS.
&&
.SHORT TERM /7 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
CLOUDS SHOULD BREAK UP IN SOUTHEAST PA FRIDAY MORNING AND BEFORE
NOON MOST OTHER LOCATIONS. THE TROUGH IS TO OUR EAST AND THE PW
VALUES BEGIN TO DROP BELOW NORMAL. WINDS TOO SHOULD SUBSIDE. THE SREF
IS LIKELY WAY TOO WET...WHATS NEW...AND THE NAM IS VERY DRY (NOT
LIKE 2 DAYS AGO). THE INSTABILITY DOES NOT LOOK AS PROMISING. SO
DROPPED ALL MENTIONS OF CHANCE POPS TO TRY TO GET SLIGHT CHANCE OF
POP CORN SHOWERS AND ISOLATED THUNDERSTORMS.
TEMPERATURES SHOULD RANGE FROM THE 60S NW TO LOW-MID 70S
SOUTHEAST. SOME INSTABILITY CLOUDS IN AFTERNOON AND OF COURSE THE
SLIGHT RISK OF A SHOWER AND EVEN AN ISOLATED THUNDERSTORM.
FRIDAY IS REALLY JUST SETTING THE TABLE AS WE DRY OUT FOR WHAT
PROMISES TO BE A SPECTACULAR SATURDAY!
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE SLIDES SOUTHWARD OUT OF CANADA FOR THE WEEKEND...AND
WILL LEAD TO DRY WEATHER FOR FRI NIGHT...SAT AND SAT NIGHT. THE
MORNING LOWS ON SATURDAY WILL BE IN THE 40S IN THE NRN MTS AND
L50S FOR MOST OF THE AREA. THESE VALUES WILL SEEM DRASTICALLY COLD
FOR THE MIDDLE OF JUNE...BUT ARE REALLY ONLY 5 TO 10F BELOW
NORMAL. TEMPS SHOULD REBOUND TO NEAR NORMAL ON SAT UNDER NEARLY
FULL SUN. UPPER RIDGE FLATTENS OUT AS A BIG SYSTEM PUSHES OVER THE
TOP OF IT ACROSS THE NRN PLAINS AND CANADIAN PLAINS. HIGH PRESSURE
SETTLES TO THE SOUTH OF THE REGION AND RETURN FLOW WILL BRING
MOISTURE AND PRECIP CHCS BACK ON SUNDAY. POPS WILL STAY IN THE MID
RANGE FOR THE FIRST PART OF THE WEEK AS THE STORM SLIDES THROUGH
IN A FEW PIECES. THIS WILL LEAD TO A PERSISTENT FRONTAL BOUNDARY
LYING ACROSS THE OHIO VALLEY AND MID ATLANTIC. THUS...TEMPS SHOULD
HANG NEAR NORMALS...PERHAPS A LITTLE BELOW NORMAL ON MAXES AND
ABOVE NORMAL ON MINS FOR MUCH OF THE PERIOD. AN UPPER TROUGH WILL
FORM BRIEFLY OVER THE NERN STATES AND COULD DELAY THE EXIT OF
PRECIP/SHOWERS FROM THE NERN COS UNTIL THE END OF THE LONG RANGE
PERIOD. THUS JUST A MINOR ADDITION OF LOW CHC POPS FOR DAY7 AND
THEN DRYNESS RETURNS WITH HIGH PRESSURE FOR THE NEW DAY8/NEXT
THURS.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS LOW PRESSURE SYSTEM PULLS AWAY RAPIDLY TO THE EAST...MUCH OF
THE SHOWER ACTIVITY OVER CENTRAL AREAS HAS COME TO AN END.
HOWEVER...ACROSS THE SUSQUEHANNA VALLEY...BACK EDGE OF LIGHT
RAIN HAS YET TO END...AND MOST LIKELY WILL BE EAST OF THE AREA BY
02Z/03Z. ANOTHER BAND OF RESIDUAL MOISTURE NOTED ON RADAR ROTATING
BACK INTO NORTHWEST AND WESTERN PA. GENERAL TREND FOR THIS
PRECIPITATION HAS BEEN TO DECREASE IN INTENSITY OVER THE PAST
HOUR. STILL ENOUGH COVERAGE TO INCLUDE VCSH IN KBFD AND KJST TAFS
FOR MUCH OF THE NIGHT.
OVERALL...MVFR TO OCNL IFR CIGS PREVAIL OVER MUCH OF CENTRAL
PENNSYLVANIA...WITH ONLY FAR SOUTHEASTERN AIRFIELDS CURRENTLY VFR.
HOWEVER...WITH VESTIGES OF SHOWERS STILL MOVING THROUGH THAT AREA...WILL
LIKELY SEE RESTRICTIONS BACK TO MVFR FOR A WHILE OVER THE NEXT FEW
HOURS...SO INCLUDED A SHORT TEMPO GROUP AT KMDT AND KLNS TO COVER
OCNL MVFR CIGS AND VSBYS IN SHRA.
LOW CLOUD DECK WILL PREVAIL OVERNIGHT...ALTHOUGH CENTRAL TAF
LOCATIONS /KAOO AND KUNV/ ARE SHOWING SIGNS OF DOWNSLOPE DRYING
AND TRYING TO BREAK INTO LOW VFR CONDITIONS. HAVE CONTINUED
THINKING OF PREVIOUS FORECASTS AND GUIDANCE AND RAISED CIGS AT
THESE LOCATIONS TO VFR AROUND MIDNIGHT.
IMPROVEMENT IN FORECAST FOR FRIDAY MORNING AS MIXING AND DRY
ADVECTION WILL ALLOW FOR EVERYONE TO BECOME OR STAY VFR.
HOWEVER...A DISTURBANCE ALOFT MAY ONCE AGAIN INTRODUCE ISOLATED/SCATTERED
SHOWERS AND PERHAPS A THUNDERSTORM INTO THE PICTURE MAINLY DURING
THE AFTERNOON. ONLY ENOUGH CONFIDENCE TO INTRODUCE VCSH TO KBFD
AND KJST AT THIS TIME. THE WIND ALSO REMAIN GUSTY OUT OF THE
NORTHWEST...IN THE 10-25 MPH RANGE.
OUTLOOK...
SAT...NO SIG WX.
SUN-TUE...MAINLY VFR WITH SCATTERED SOWERS AND THUNDERSTORMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...DANGELO
AVIATION...JUNG/LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
759 AM EDT WED JUN 12 2013
.SYNOPSIS...
A QUASI-STATIONARY FRONT WILL REMAIN DRAPED FROM THE NORTHWEST
CORNER OF THE STATE...TO SOUTH-CENTRAL PENNSYLVANIA TODAY. THIS
FRONTAL BOUNDARY WILL PIVOT SLIGHTLY TO A MORE EAST-WEST DIRECTION
TONIGHT. A POTENT STORM WILL RIDE ALONG THIS BOUNDARY...PASSING OVER
SOUTHERN OR CENTRAL PENNSYLVANIA ON THURSDAY. A COLD FRONT WILL DIVE
SOUTHEAST ACROSS THE REGION ON FRIDAY...FOLLOWED BY A LARGE HIGH
PRESSURE SYSTEM FOR SATURDAY.
&&
.NEAR TERM /UNTIL NOON TODAY/...
A NEARLY STATIONARY...AND VERY SHARP 925-850 MB THETA-E BOUNDARY WAS
LOCATED FROM KERI...SE TO KFKL...KAOO AND KHGR EARLY THIS MORNING.
A PULSE OF HIGHER PWAT AIR AND WESTERLY FLOW AROUND THE 850 MB LEVEL
IMPINGING ON THIS BOUNDARY WILL HELP TO FORM ONE OR MORE AREAS OF
SHOWERS THAT WILL SLIDE SEWRD /NEAR AND JUST TO THE EAST OF THE
BOUNDARY/ THIS MORNING. ONE OR TWO...COMPACT AND LOW-TOPPED TSRA
CAN/T BE RULED OUT ACROSS THE LAURELS THIS MORNING ON THE SW SIDE OF
THE BOUNDARY.
RAINFALL AMOUNTS WILL BE GENERALLY LIGHT AND LESS THAN ONE TENTH OF
AN INCH ACROSS THE CENTRAL AND WESTERN ZONES. HOWEVER...SHORT
RANGE/HIGH RES NAM AND HRRR GUIDANCE IMPLIES THAT A FEW LOCATIONS
COULD RECEIVE SLIGHTLY HIGHER AMOUNTS THROUGH 15Z.
THE HIGHER PWAT AIR AND LLVL BOUNDARY IS BRIEFLY SHUNTED A BIT TO
THE SOUTHWEST THIS AFTERNOON...THANKS TO VERTICAL MIXING OF MUCH
DRIER AIR ALOFT AHEAD OF WEAK RIDGING THAT WILL BE SLIDING EAST OVER
THE REGION.
LOW TEMPS AROUND DAYBREAK TODAY WILL RANGE FROM THE MID 50S OVER THE
NORTH TO AROUND 60 IN THE SOUTH.
&&
.SHORT TERM /NOON TODAY THROUGH 6 PM THURSDAY/...
QUASI-STATIONARY FRONT STAYS HUNG UP OVER SWRN PA THROUGH TODAY.
DESPITE LACK OF SIG LG SCALE FORCING ON WED...DIURNAL HEATING
COMBINED LIFT ALONG STATIONARY FRONT SHOULD SUPPORT SCT AFTN/EVENING
SHOWERS AND THUNDERSTORMS OVER MY SW COUNTIES.
EXPECT SKIES TO STAY MOSTLY CLOUDY FOR MUCH OF TODAY WITH VARYING
AMOUNTS OF HIGH-BASED STRATO CU AND ALTO CU STREAMING SEWRD ACROSS
THE STATE.
SPC HAS TRANSITIONED FROM THEIR DAY 2 TO DAY 1 SLIGHT /AND MDT/ RISK
AREAS OVER THE SW HALF OF PENN...OUT THROUGH THE OHIO VALLEY -
VIRTUALLY UNCHANGED.
THINKING IS THAT THE PRIMARY RISK FOR OUR REGION WILL BE ASSOCIATED
WILL LATER DEVELOPMENTS OVER THE MIDWEST THAT COULD MOVE IN TONIGHT
AND EARLY THURSDAY...SO FOR RIGHT NOW THIS AFTERNOON AND EVENING
DOESN/T LOOK TERRIBLY THREATENING OVERALL...AS THE BEST INSTABILITY
SOUTH AND WEST OF OUR AREA OF CONCERN THROUGH MOST OF THIS TIME
FRAME.
ALTHOUGH CLOUDS MAY PREDOMINATE TODAY...BREAKS OF SUN AND LOW
CHANCES FOR PRECIP DURING THE LATE MORNING AND AFTERNOON HOURS
SHOULD ALLOW TEMPS TO RECOVER TO NEAR NORMAL OVR THE NORTH AND
LIKELY A BIT ABV NORMAL IN THE SOUTH...WHERE ENS MEAN 8H TEMPS GET
CLOSE TO 15C. MUCH HIGHER PWAT AIR WILL BEGIN IT/S BIG SURGE NE
ACROSS THE FCST AREA VERY LATE TODAY AND TONIGHT.
ABNORMALLY STRONG DYNAMICS WILL SUPPORT A DEEP LOW MOVING ACROSS
SCENT PA ON THU.
POTENT UPPER SHORT WAVE ACCOMPANIED BY A STRONG WSWRLY LLJ /AND THE
SUB-1000MB SFC LOW/ WILL IMPACT ALL OF THE REGION THURSDAY WITH A
WIDE RANGE OF TEMPERATURES AND WEATHER.
LATEST...00Z/03Z OPERATIONAL MODELS AND THEIR RESPECTIVE ENSEMBLES
REMAIN IN VERY GOOD AGREEMENT TRACKING AN ANOMALOUSLY STRONG 990-995
MB SFC LOW ACROSS CENTRAL OR SOUTHERN PENN DURING THE DAY THURSDAY.
DEEP UVVEL BENEATH THE THERMALLY DIRECT BRANCH OF AN UPPER JET
LOCATED ACROSS NEW YORK AND SRN NEW ENGLAND WILL AID IN STRONG
ASCENT OF THE HIGH PWAT AIR /1.5-2 INCHES/ OVER THE QUASI STNRY OR
SFC WARM FRONT /EXPECTED TO BE SITUATED FROM WCENT PENN TO THE SCENT
MTNS AND LOWER SUSQ VALLEY/. THESE FACTORS WILL COMBINE TO PRODUCE A
WIDESPREAD...SOAKING RAINFALL OF 1-2 INCHES ACROSS THE NORTHERN HALF
OF THE STATE. 24 SREF PROB FOR 2 INCH OR GREATER RAINFALL IS 40-50
PERCENT ACROSS THE NORTHERN 1/2 OF PENN...WHILE ITS 24 HR
PROBABILITY FOR OVER 1 INCH OF QPF IS 60-80 PERCENT STATE-WIDE.
ACROSS THE SOUTH...IN THE MUCH WARMER AND MORE HUMID AIR /ESP NEAR
AND TO THE SOUTH OF THE PENN TURNPIKE/...SIGNIFICANT BREAKS IN THE
CLOUD COVER MAY DEVELOP HELPING TO RAMP UP MUCAPES TO BETWEEN
2000-3000 J/KG IN THE AFTERNOON. THIS CONVECTIVE ENERGY WILL BE NEAR
THE NORTHERN EDGE OF THE MOST ANOMALOUS /PLUS 3 SIGMA/ WSW 850 MB
FLOW.
A RATHER BROAD AREA OF UNUSUALLY HIGH...0-1KM EHI FOR THIS AREA /OF
AROUND 2-3M2/S2/ IS FCST TO DEVELOP NEAR AND JUST SOUTH OF THE
SLOW-MOVING WARM FRONTAL BOUNDARY TO POSE A THREAT FOR BOWING LINE
SEGMENTS WITH SCATTERED SUPERCELLS/ISOLATED TORNADOES POSSIBLE FROM
THE LATE MORNING THROUGH THE AFTERNOON HOURS. SPC HAS COVERED
ROUGHLY THE SERN HALF OF PENN WITH THEIR DAY 2 SLIGHT RISK
AREA...WHILE THE FAR SERN ZONES ARE AT THE NW EDGE OF A MDT RISK
/WHICH EXTENDS SOUTH THROUGH THE I-95...MID ATLANTIC CORRIDOR/.
A RIBBON OF VERY IMPRESSIVE /AND NOT OFTEN SEEN IN THIS AREA/ 0-1KM
EHIS OF 4M2/S2 OR GREATER DEVELOP ACROSS THE LOWER SUSQ WHERE THE
MID-LATE AFTERNOON TIMING OF THE BEST INSTABILITY AND LLVL SHEAR
WILL OCCUR INVOF OF THE THE SHARP STNRY FRONT /OR SLOWLY MOVING WARM
FRONTAL BOUNDARY/. SIGNIF PERCENTAGE OF THE STORMS IN THE LOWER SUSQ
COULD CONTAIN MDT TO STRONG MESOS FOR UP TO SVRL HOURS THURSDAY
AFTERNOON AND EVENING INVOF KTHV...KMDT AND KLNS WITH AN ENHANCED
THREAT FOR A FEW TORNADOES IN THAT AREA. LOW LCL HEIGHTS AND THE
VERY STRONG SOUTH-SWRLY 0-1KM SHEAR NEAR AND JUST TO THE NORTH OF
THE BOUNDARY WILL CREATE THE GREATEST THREAT FOR THE SUPERCELLS WITH
POSSIBLE LARGE HAIL IN THE 17Z-22Z PERIOD ACROSS THE LOWER SUSQ
VALLEY.
AS HIGHLIGHTED LAST NIGHT...THE NORTH-SOUTH SFC TEMP GRADIENT
THURSDAY AFTERNOON SHOULD TURN OUT TO BE QUITE SHARP...ESPECIALLY IF
SIGNIFICANT BREAKS FORM ACROSS THE SOUTH.
EARLIER WENT ALL IN BY RAISING POPS TO 100 PERCENT FOR THE ENTIRE
AREA THURSDAY...AND THIS LOOKS TO BE A WISE MOVE BASED ON THE SHORT
RANGE OPERATIONAL AND ENSEMBLE MODEL CONSENSUS OF WIDESPREAD HEAVY
RAIN AND CONVECTION.
WILL MAINTAIN TEMPS BELOW GUIDANCE...GIVEN CLDS AND SOAKING RAIN
BENEATH THE WELL DEFINED...THERMALLY DIRECT BRANCH OF A STRONG UPPER
LEVEL JET. THE SECOND CONCERN IS HEAVY RAIN...AND POTENTIAL FOR
LOCALIZED FLASH FLOODING/FLOODING OF STREAMS AND CREEKS.
24-30 HOUR...STORM TOTAL QPF RANGES FROM 2-2.5 INCHES ACROSS MUCH OF
NRN PENN...TO SLIGHTLY UNDER ONE INCH IN THE FAR SE.
MARFC IS IN THE 2 TO 3 INCH RANGE FOR STORM TOTAL QPF. MOST PLACES
SHOULD BE ABLE TO HANDLE THIS AMT OF RAIN OVER A 12-24 HOUR PERIOD.
HOWEVER...IF MUCH OF THIS COMES DOWN IN JUST A 3-6 HOUR
PERIOD...SIGNIFICANT PROBLEMS COULD DEVELOP QUICKLY IN TYPICALLY
FLOOD PRONE AREAS.
COORDINATED WITH SURROUNDING WFOS TO HOLD OFF ON A FLASH FLOOD WATCH
AT THIS POINT...ESP SINCE THE BULK OF THE RAIN IS STILL CONFINED TO
THE 3RD PERIOD OF THE FCST...AND FFG FOR OUR CWA IS SOME OF THE
HIGHEST OBSERVED IN THE ENTIRE MID-ATLANTIC REGION /2.25 - 3 INCHES
PER 12 HOURS OVER OUR ENTIRE CWA/. AREAS TO THE WEST AND EAST OF OUR
FCST AREA NEED SIGNIFICANTLY LOWER AMOUNTS OF RAIN TO CAUSE FLOODING
PROBLEMS...ESPECIALLY OVER TO OUR EAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
DID LOWER TEMPS ON FRIDAY BY 2 TO 5 DEGREES...COMBINATION OF
SECONDARY COLD FRONT DROPPING SOUTHWARD FROM SOUTHERN
ONTARIO...AND DEEP LOW MOVING OFF THE COAST WILL SUPPORT MORE COLD
ADVECTION AND ALSO SOME SHOWERS FRIDAY MORNING.
IMPROVING CONDITIONS FOR SAT.
WENT WITH A LOW CHC FOR SHOWERS AND STORMS ON SUNDAY...GIVEN
WARM ADVECTION.
CHC OF MORE SHOWERS AND STORMS ON MONDAY AND TUE...AS THE WARM
FRONT MOVES NE ON MONDAY...FOLLOWED BY A COLD FRONT ON TUE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
A QUASI-STATIONARY FRONTAL BOUNDARY WILL SAG SLOWLY SOUTHWARD
ACROSS WESTERN PENNSYLVANIA TODAY. A POTENT STORM WILL RIDE ALONG
THIS BOUNDARY LATE WED NIGHT THROUGH THU NIGHT.
KBFD WILL REMAIN IFR/MVFR FOR A COUPLE MORE HOURS. AREA OF MVFR
CIGS HAS EXPANDED SOUTH AND EAST INTO THE LAURELS AND SOUTH
CENTRAL MTNS AS SHORTWAVE SLIPS OVERHEAD WITH ENOUGH LIFT TO
DEVELOP STRATOCU UNDER INVERSION. SCT SHOWERS IN THAT REGION WILL
CONTINUE TO DECREASE THROUGH MID MORNING...WITH ALL TAF SITES
IMPROVING TO VFR 14-15Z AS LOWER LAYER MIXES AND HIGH PRESSURE
SLIDES ACROSS NY STATE. DESPITE LACK OF SIG LARGE SCALE
FORCING...DIURNAL HEATING COMBINED WITH LIFT ALONG STATIONARY
FRONT SHOULD SUPPORT SCT AFTN/EVENING TSTMS NEAR KJST- KAOO.
THEN FOCUS TURNS TO POTENT LOW PRESSURE SYSTEM APPROACHING FROM
THE MIDWEST...WITH IMPACTS BEGINNING WED NIGHT. LARGE AREA OF
PRECIP OVERSPREADS REGION FROM THE WEST AS NIGHT PROGRESSES.
MODELS INDICATING THAT CIGS REMAIN PRIMARILY VFR EXCEPT ACROSS THE
WEST...WHERE RESTRICTIONS WILL DEVELOP. RAIN CONTINUES THROUGH
THURSDAY NIGHT...WITH POTENTIAL FOR LARGE IMPACTS FROM STRONG
THUNDERSTORMS AND WIND SHEAR THU AFT INTO THU EVE.
LLWS WILL DEVELOP IN THE SW LATE TONIGHT...WITH STRONGER LOW LEVEL
WINDS IN STORE FOR ALL ON THURSDAY.
OUTLOOK...
WED NIGHT-THU MORN...RAIN AND SCT TSTMS BECOMING MORE WIDESPREAD.
REDUCTIONS DEVELOPING...MAINLY WEST.
THU AFT-THU NIGHT...LARGE IMPACTS FROM STRONG TSTMS AND WIND SHEAR
LIKELY. OTHERWISE SHOWERS CONTINUE. REDUCTIONS ALL AREAS THU AFT-
EVE...THEN WIDESPREAD REDUCTIONS NW HALF THU NIGHT.
FRI...CHANCE OF SHOWERS...MAINLY EARLY. PRIMARILY VFR CONDITIONS.
SAT...NO SIG WX.
SUN...NO SIG WX. ISO TSTMS LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...MARTIN
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
345 AM EDT WED JUN 12 2013
.SYNOPSIS...
A QUASI-STATIONARY FRONT WILL REMAIN DRAPED FROM THE NORTHWEST
CORNER OF THE STATE...TO SOUTH-CENTRAL PENNSYLVANIA TODAY. THIS
FRONTAL BOUNDARY WILL PIVOT SLIGHTLY TO A MORE EAST-WEST DIRECTION
TONIGHT. A POTENT STORM WILL RIDE ALONG THIS BOUNDARY...PASSING OVER
SOUTHERN OR CENTRAL PENNSYLVANIA ON THURSDAY. A COLD FRONT WILL DIVE
SOUTHEAST ACROSS THE REGION ON FRIDAY...FOLLOWED BY A LARGE HIGH
PRESSURE SYSTEM FOR SATURDAY.
&&
.NEAR TERM /UNTIL NOON TODAY/...
A NEARLY STATIONARY...AND VERY SHARP 925-850 MB THETA-E BOUNDARY WAS
LOCATED FROM KERI...SE TO KFKL...KAOO AND KHGR EARLY THIS MORNING.
A PULSE OF HIGHER PWAT AIR AND WESTERLY FLOW AROUND THE 850 MB LEVEL
IMPINGING ON THIS BOUNDARY WILL HELP TO FORM ONE OR MORE AREAS OF
SHOWERS THAT WILL SLIDE SEWRD /NEAR AND JUST TO THE EAST OF THE
BOUNDARY/ THIS MORNING. ONE OR TWO...COMPACT AND LOW-TOPPED TSRA
CAN/T BE RULED OUT ACROSS THE LAURELS THIS MORNING ON THE SW SIDE OF
THE BOUNDARY.
RAINFALL AMOUNTS WILL BE GENERALLY LIGHT AND LESS THAN ONE TENTH OF
AN INCH ACROSS THE CENTRAL AND WESTERN ZONES. HOWEVER...SHORT
RANGE/HIGH RES NAM AND HRRR GUIDANCE IMPLIES THAT A FEW LOCATIONS
COULD RECEIVE SLIGHTLY HIGHER AMOUNTS THROUGH 15Z.
THE HIGHER PWAT AIR AND LLVL BOUNDARY IS BRIEFLY SHUNTED A BIT TO
THE SOUTHWEST THIS AFTERNOON...THANKS TO VERTICAL MIXING OF MUCH
DRIER AIR ALOFT AHEAD OF WEAK RIDGING THAT WILL BE SLIDING EAST OVER
THE REGION.
LOW TEMPS AROUND DAYBREAK TODAY WILL RANGE FROM THE MID 50S OVER THE
NORTH TO AROUND 60 IN THE SOUTH.
&&
.SHORT TERM /NOON TODAY THROUGH 6 PM THURSDAY/...
QUASI-STATIONARY FRONT STAYS HUNG UP OVER SWRN PA THROUGH TODAY.
DESPITE LACK OF SIG LG SCALE FORCING ON WED...DIURNAL HEATING
COMBINED LIFT ALONG STATIONARY FRONT SHOULD SUPPORT SCT AFTN/EVENING
SHOWERS AND THUNDERSTORMS OVER MY SW COUNTIES.
EXPECT SKIES TO STAY MOSTLY CLOUDY FOR MUCH OF TODAY WITH VARYING
AMOUNTS OF HIGH-BASED STRATO CU AND ALTO CU STREAMING SEWRD ACROSS
THE STATE.
SPC HAS TRANSITIONED FROM THEIR DAY 2 TO DAY 1 SLIGHT /AND MDT/ RISK
AREAS OVER THE SW HALF OF PENN...OUT THROUGH THE OHIO VALLEY -
VIRTUALLY UNCHANGED.
THINKING IS THAT THE PRIMARY RISK FOR OUR REGION WILL BE ASSOCIATED
WILL LATER DEVELOPMENTS OVER THE MIDWEST THAT COULD MOVE IN TONIGHT
AND EARLY THURSDAY...SO FOR RIGHT NOW THIS AFTERNOON AND EVENING
DOESN/T LOOK TERRIBLY THREATENING OVERALL...AS THE BEST INSTABILITY
SOUTH AND WEST OF OUR AREA OF CONCERN THROUGH MOST OF THIS TIME
FRAME.
ALTHOUGH CLOUDS MAY PREDOMINATE TODAY...BREAKS OF SUN AND LOW
CHANCES FOR PRECIP DURING THE LATE MORNING AND AFTERNOON HOURS
SHOULD ALLOW TEMPS TO RECOVER TO NEAR NORMAL OVR THE NORTH AND
LIKELY A BIT ABV NORMAL IN THE SOUTH...WHERE ENS MEAN 8H TEMPS GET
CLOSE TO 15C. MUCH HIGHER PWAT AIR WILL BEGIN IT/S BIG SURGE NE
ACROSS THE FCST AREA VERY LATE TODAY AND TONIGHT.
ABNORMALLY STRONG DYNAMICS WILL SUPPORT A DEEP LOW MOVING ACROSS
SCENT PA ON THU.
POTENT UPPER SHORT WAVE ACCOMPANIED BY A STRONG WSWRLY LLJ /AND THE
SUB-1000MB SFC LOW/ WILL IMPACT ALL OF THE REGION THURSDAY WITH A
WIDE RANGE OF TEMPERATURES AND WEATHER.
LATEST...00Z/03Z OPERATIONAL MODELS AND THEIR RESPECTIVE ENSEMBLES
REMAIN IN VERY GOOD AGREEMENT TRACKING AN ANOMALOUSLY STRONG 990-995
MB SFC LOW ACROSS CENTRAL OR SOUTHERN PENN DURING THE DAY THURSDAY.
DEEP UVVEL BENEATH THE THERMALLY DIRECT BRANCH OF AN UPPER JET
LOCATED ACROSS NEW YORK AND SRN NEW ENGLAND WILL AID IN STRONG
ASCENT OF THE HIGH PWAT AIR /1.5-2 INCHES/ OVER THE QUASI STNRY OR
SFC WARM FRONT /EXPECTED TO BE SITUATED FROM WCENT PENN TO THE SCENT
MTNS AND LOWER SUSQ VALLEY/. THESE FACTORS WILL COMBINE TO PRODUCE A
WIDESPREAD...SOAKING RAINFALL OF 1-2 INCHES ACROSS THE NORTHERN HALF
OF THE STATE. 24 SREF PROB FOR 2 INCH OR GREATER RAINFALL IS 40-50
PERCENT ACROSS THE NORTHERN 1/2 OF PENN...WHILE ITS 24 HR
PROBABILITY FOR OVER 1 INCH OF QPF IS 60-80 PERCENT STATE-WIDE.
ACROSS THE SOUTH...IN THE MUCH WARMER AND MORE HUMID AIR /ESP NEAR
AND TO THE SOUTH OF THE PENN TURNPIKE/...SIGNIFICANT BREAKS IN THE
CLOUD COVER MAY DEVELOP HELPING TO RAMP UP MUCAPES TO BETWEEN
2000-3000 J/KG IN THE AFTERNOON. THIS CONVECTIVE ENERGY WILL BE NEAR
THE NORTHERN EDGE OF THE MOST ANOMALOUS /PLUS 3 SIGMA/ WSW 850 MB
FLOW.
A RATHER BROAD AREA OF UNUSUALLY HIGH...0-1KM EHI FOR THIS AREA /OF
AROUND 2-3M2/S2/ IS FCST TO DEVELOP NEAR AND JUST SOUTH OF THE
SLOW-MOVING WARM FRONTAL BOUNDARY TO POSE A THREAT FOR BOWING LINE
SEGMENTS WITH SCATTERED SUPERCELLS/ISOLATED TORNADOES POSSIBLE FROM
THE LATE MORNING THROUGH THE AFTERNOON HOURS. SPC HAS COVERED
ROUGHLY THE SERN HALF OF PENN WITH THEIR DAY 2 SLIGHT RISK
AREA...WHILE THE FAR SERN ZONES ARE AT THE NW EDGE OF A MDT RISK
/WHICH EXTENDS SOUTH THROUGH THE I-95...MID ATLANTIC CORRIDOR/.
A RIBBON OF VERY IMPRESSIVE /AND NOT OFTEN SEEN IN THIS AREA/ 0-1KM
EHIS OF 4M2/S2 OR GREATER DEVELOP ACROSS THE LOWER SUSQ WHERE THE
MID-LATE AFTERNOON TIMING OF THE BEST INSTABILITY AND LLVL SHEAR
WILL OCCUR INVOF OF THE THE SHARP STNRY FRONT /OR SLOWLY MOVING WARM
FRONTAL BOUNDARY/. SIGNIF PERCENTAGE OF THE STORMS IN THE LOWER SUSQ
COULD CONTAIN MDT TO STRONG MESOS FOR UP TO SVRL HOURS THURSDAY
AFTERNOON AND EVENING INVOF KTHV...KMDT AND KLNS WITH AN ENHANCED
THREAT FOR A FEW TORNADOES IN THAT AREA. LOW LCL HEIGHTS AND THE
VERY STRONG SOUTH-SWRLY 0-1KM SHEAR NEAR AND JUST TO THE NORTH OF
THE BOUNDARY WILL CREATE THE GREATEST THREAT FOR THE SUPERCELLS WITH
POSSIBLE LARGE HAIL IN THE 17Z-22Z PERIOD ACROSS THE LOWER SUSQ
VALLEY.
AS HIGHLIGHTED LAST NIGHT...THE NORTH-SOUTH SFC TEMP GRADIENT
THURSDAY AFTERNOON SHOULD TURN OUT TO BE QUITE SHARP...ESPECIALLY IF
SIGNIFICANT BREAKS FORM ACROSS THE SOUTH.
EARLIER WENT ALL IN BY RAISING POPS TO 100 PERCENT FOR THE ENTIRE
AREA THURSDAY...AND THIS LOOKS TO BE A WISE MOVE BASED ON THE SHORT
RANGE OPERATIONAL AND ENSEMBLE MODEL CONSENSUS OF WIDESPREAD HEAVY
RAIN AND CONVECTION.
WILL MAINTAIN TEMPS BELOW GUIDANCE...GIVEN CLDS AND SOAKING RAIN
BENEATH THE WELL DEFINED...THERMALLY DIRECT BRANCH OF A STRONG UPPER
LEVEL JET. THE SECOND CONCERN IS HEAVY RAIN...AND POTENTIAL FOR
LOCALIZED FLASH FLOODING/FLOODING OF STREAMS AND CREEKS.
24-30 HOUR...STORM TOTAL QPF RANGES FROM 2-2.5 INCHES ACROSS MUCH OF
NRN PENN...TO SLIGHTLY UNDER ONE INCH IN THE FAR SE.
MARFC IS IN THE 2 TO 3 INCH RANGE FOR STORM TOTAL QPF. MOST PLACES
SHOULD BE ABLE TO HANDLE THIS AMT OF RAIN OVER A 12-24 HOUR PERIOD.
HOWEVER...IF MUCH OF THIS COMES DOWN IN JUST A 3-6 HOUR
PERIOD...SIGNIFICANT PROBLEMS COULD DEVELOP QUICKLY IN TYPICALLY
FLOOD PRONE AREAS.
COORDINATED WITH SURROUNDING WFOS TO HOLD OFF ON A FLASH FLOOD WATCH
AT THIS POINT...ESP SINCE THE BULK OF THE RAIN IS STILL CONFINED TO
THE 3RD PERIOD OF THE FCST...AND FFG FOR OUR CWA IS SOME OF THE
HIGHEST OBSERVED IN THE ENTIRE MID-ATLANTIC REGION /2.25 - 3 INCHES
PER 12 HOURS OVER OUR ENTIRE CWA/. AREAS TO THE WEST AND EAST OF OUR
FCST AREA NEED SIGNIFICANTLY LOWER AMOUNTS OF RAIN TO CAUSE FLOODING
PROBLEMS...ESPECIALLY OVER TO OUR EAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
DID LOWER TEMPS ON FRIDAY BY 2 TO 5 DEGREES...COMBINATION OF
SECONDARY COLD FRONT DROPPING SOUTHWARD FROM SOUTHERN
ONTARIO...AND DEEP LOW MOVING OFF THE COAST WILL SUPPORT MORE COLD
ADVECTION AND ALSO SOME SHOWERS FRIDAY MORNING.
IMPROVING CONDITIONS FOR SAT.
WENT WITH A LOW CHC FOR SHOWERS AND STORMS ON SUNDAY...GIVEN
WARM ADVECTION.
CHC OF MORE SHOWERS AND STORMS ON MONDAY AND TUE...AS THE WARM
FRONT MOVES NE ON MONDAY...FOLLOWED BY A COLD FRONT ON TUE.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
A QUASI-STATIONARY FRONTAL BOUNDARY WILL REMAIN DRAPED NW-SE ACROSS
WESTERN PENNSYLVANIA TONIGHT INTO WEDNESDAY. A POTENT STORM WILL
RIDE ALONG THIS BOUNDARY LATE WED NIGHT THROUGH THU NIGHT.
EARLY THIS MORNING...VFR PREVAILING AT ALL TAF SITES EXCEPT BFD.
PROXIMITY TO THE FRONTAL BOUNDARY WILL KEEP KBFD IFR/MVFR IN
SHOWERS THROUGH SUNRISE. THE AREA OF MVFR CIGS WILL EXPAND SOUTH
AND EAST INTO THE LAURELS AND CENTRAL MTNS LATER TONIGHT /AFT
09Z/ AS A FAIR AMOUNT OF LOW LEVEL MOISTURE REMAINS TRAPPED UNDER
INVERSION...WITH SHOWERS POSS NEAR KJST TOWARD SUNRISE. LIGHT FOG
POSS IN THE SUSQ VALLEY.
ON WED...LOWER CIGS IN THE NW HALF WILL STUBBORNLY PERSIST FOR
MUCH OF THE MORNING...THEN SLOWLY IMPROVE TO VFR AS LOWER LAYER
MIXES AND HIGH PRESSURE SLIDES ACROSS NY STATE. FRONTAL BOUNDARY
SLIPS SOUTHWARD TO NEAR KJST-KAOO. DESPITE LACK OF SIG LARGE
SCALE FORCING...DIURNAL HEATING COMBINED WITH LIFT ALONG
STATIONARY FRONT SHOULD SUPPORT SCT AFTN/EVENING TSTMS NEAR KJST-
KAOO.
THEN FOCUS TURNS TO POTENT LOW PRESSURE SYSTEM APPROACHING FROM
THE MIDWEST...WITH IMPACTS BEGINNING WED NIGHT. LARGE AREA OF
PRECIP OVERSPREADS REGION FROM THE WEST AS NIGHT PROGRESSES.
MODELS INDICATING THAT CIGS REMAIN PRIMARILY VFR EXCEPT ACROSS
THE WEST...WHERE RESTRICTIONS WILL DEVELOP. RAIN CONTINUES THROUGH
THURSDAY NIGHT...WITH POTENTIAL FOR LARGE IMPACTS FROM STRONG
THUNDERSTORMS AND WIND SHEAR THU AFT INTO THU EVE.
OUTLOOK...
WED NIGHT-THU MORN...RAIN AND SCT TSTMS BECOMING MORE WIDESPREAD.
REDUCTIONS DEVELOPING...MAINLY WEST.
THU AFT-THU NIGHT...LARGE IMPACTS FROM STRONG TSTMS AND WIND SHEAR
LIKELY. OTHERWISE SHOWERS CONTINUE. REDUCTIONS ALL AREAS THU AFT-
EVE...THEN WIDESPREAD REDUCTIONS NW HALF THU NIGHT.
FRI...CHANCE OF SHOWERS...MAINLY EARLY. PRIMARILY VFR CONDITIONS.
SAT...NO SIG WX.
SUN...NO SIG WX. ISO TSTMS LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...MARTIN
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
432 PM EDT WED JUN 12 2013
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN WARM TEMPERATURES ACROSS THE REGION
TODAY AHEAD OF AN APPROACHING COLD FRONT...WHICH WILL CROSS THE AREA
ON THURSDAY. DRY HIGH PRESSURE WILL BUILD IN FROM THE NORTH
FRIDAY...MAKING FOR A MOSTLY DRY WEEKEND. THE NEXT COLD FRONT WILL
APPROACH THE REGION EARLY NEXT WEEK...TRIGGERING AFTERNOON SHOWERS
AND THUNDERSTORMS EACH DAY THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 430 PM...THERE WAS A PROBLEM WITH THE PREVIOUS FORECAST. HAVE
FIXED THIS SO THE NEW DAY 7 PERIOD IS INCLUDED. CONVECTION STILL HAS
NOT DEVELOPED OVER THE CWFA DESPITE THE VERY HIGH CAPE AND UNCAPPED
ATMOS. THIS EVEN WITH A WEAK LEE TROF IN PLACE. IN FACT...THE ONLY
PRECIP IS LIGHT SHRA FROM FALLING FROM A MID CLOUD DECK OVER THE NC
AND ERN SC PIEDMONT. GIVEN THAT THE PREVIOUS THINKING IS STILL
VALID...KEPT POP AS IS BUT TRIMMED THE START TIME AND KEPT POP OVER
NC ISOLATED. OTHERWISE... MAIN UPDATES WERE FOR CURRENT CONDITIONS.
AS OF 230 PM...SPC MESOANAL PAGE SHOWS OVER 3000J/KG OF SBCAPE ACROSS
THE REGION WITH NO CIN. WILL CONTINUE THE IDEA PER HRRR/4KM EMC WRF
AND HI-RES WRF THAT SCT THUNDERSTORMS WILL DEVELOP OVER THE WESTERN
UPSTATE/NE GA BY LATE AFTERNOON TRIGGERED BY A MID LEVEL VORT. THE
ENTIRE AREA IS INCLUDED IN A SPC SLGT RISK AREA. THIS MAKES SENSE IN
THAT ANY STORMS THAT DEVELOP HAVE THE POTENTIAL TO PRODUCE LOCALIZED
DAMAGING WINDS PER THE 900J OF DCAPE ANALYZED BY SPC. CONVECTION IS
EXPECTED TO MOVE OUT OF THE AREA BY 00Z.
THE OVERNIGHT SHOULD BE QUIET AS A WEAK RIDGE OF HIGH PRESSURE NOSES
EASTWARD INTO THE AREA. HOWEVER...WE WILL BE KEEPING AN EYE UPSTREAM
OVER THE LOWER GREAT LAKES WHERE A CONVECTIVE COMPLEX IS EXPECTED
TO DEVELOP AND PERHAPS TRANSITION INTO A DERECHO AS IT MOVES SE
THROUGH THE OHIO VALLEY AND INTO THE APPALACHIANS. THE 4KM EMC WRF
SHOWS THIS FEATURE MAKING A RUN AT THE NC MOUNTAINS LATE
TONIGHT...THEN DISSIPATING IT AS IT HITS THE MOUNTAINS. HAVE BUMPED
SOME CHC POPS UP TO ABOUT 12Z OVER THE NC BORDER COUNTIES TO ACCOUNT
FOR THIS. CAN`T RULE OUT SOME GUSTY WINDS REACHING THE AREA THU
MORNING FROM DERECHO OUTFLOW...BUT DO NOT HAVE THAT POSSIBILITY
CODED INTO THE GRIDS. IT WILL BE A WARM AND MUGGY NIGHT WITH LOWS
NOT GETTING OUT OF THE 70S FOR MOST AREAS EAST OF THE MOUNTAINS.
ON THU...A COLD FRONT IS STILL EXPECTED TO ARRIVE AND MOVE ACROSS
THE AREA DURING THE COURSE OF THE DAY. WIND FIELDS WILL BE IMPROVING
WITH 0-6KM BULK SHEAR INCREASING TO 35-40KT AND CAPES >2500J.
HENCE...SVR STORMS ARE CERTAINLY POSSIBLE PER THE SPC DAY 2 OUTLOOK.
LOOKS LIKE THE BEST THREAT FOR SEVERE STORMS WILL BE OVER THE
PIEDMONT IN THE MID TO LATE AFTERNOON HOURS. WINDS THROUGH THE
COLUMN WILL TAKE ON A DOWNSLOPE COMPONENT ON THU SO IT IS POSSIBLE
THAT COVERAGE ESPECIALLY ACROSS THE UPSTATE PERHAPS WILL NOT BE
100%. HENCE...POPS ARE HIGHEST ACROSS THE SOUTHERN PIEDMONT AREAS.
IT WILL BE ANOTHER HOT DAY ON THU WITH A MODEL BLEND PRODUCING HIGHS
IN THE 90-95 RANGE OUTSIDE THE MOUNTAINS AND MID 80S MOUNTAIN
VALLEYS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 130 PM EDT WEDNESDAY...EXPECT QUIET AND COOLER CONDITIONS FOR
THE SHORT TERM PERIOD. CONDITIONS QUICKLY DRY OUT THURSDAY EVENING
AS A SHARP UPPER TROUGH AXIS AND ASSOCIATED SURFACE COLD FRONT PUSH
EAST OF THE AREA. HOWEVER...SCATTERED LIGHT SHOWERS MAY CONTINUE
ACROSS THE NC MTNS THROUGH LATE THURSDAY NIGHT DUE TO INCREASING NW
UPSLOPE FLOW ALONG WITH THE PASSAGE OF WEAK UPPER DPVA THERE.
AN UPPER RIDGE OF H5 HIGH WILL REMAIN ANCHORED OVER THE SOUTHCENTRAL
STATES LEAVING OUR FORECAST AREA UNDER THE NW FLOW ALOFT FRI/SAT.
THIS WILL ALLOW CANADIAN SURFACE HIGH PRESSURE TO RIDGE SOUTH INTO
THE FORECAST AREA PROVIDING DRY NORTHERLY FLOW THROUGH THE PERIOD.
TEMPERATURES WILL BE AROUND 2-3 DEGREES BELOW NORMAL WITH HIGHS IN
THE LOWER TO MID 80S OVER THE PIEDMONT AND 70S IN THE HIGHER
TERRAIN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 2PM WEDNESDAY...THE MODELS REMAIN IN FAIRLY GOOD AGREEMENT
THROUGH MOST OF THE PERIOD. AFTER A PREDOMINANTLY DRY WEEKEND...THE
RIDGE OVER THE EASTERN CONUS WILL BREAK DOWN BY THE BEGINNING OF
NEXT WEEK. A WEAK TROUGH WILL THEN SET UP OVER THE SOUTHEASTERN
CONUS AND ALLOW A MORE UNSETTLED SUMMERTIME PATTERN TO RETURN. THE
NEXT FRONTAL SYSTEM APPROACHES LATE MONDAY/EARLY TUESDAY...RESULTING
IN DIURNAL CHANCE POPS FOR THE ENTIRE CWA ON MONDAY. THE FRONT
PASSES AND STALLS OUT JUST TO THE SOUTH OF THE FORECAST AREA LATE
TUESDAY...SO CHANCE POPS CONTINUE FOR THE ENTIRE FORECAST AREA
THROUGH MIDWEEK. TEMPERATURES WILL REMAIN NEAR NORMAL THROUGH THE
EXTENDED PERIOD.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...VFR THROUGH THE FORECAST PERIOD. SPC MESOANAL PAGE STILL
SHOWS SOME CONVECTIVE INHIBITION. ALSO...CONVECTION ALLOWING MODELS
SHOWING DEEP CONVECTION DEVELOPING WELL WEST OF THE AIRFIELD CLOSER
TO THE WEAK FORCING ASSOCIATED WITH A MID LEVEL VORT. HENCE...HAVE
NOT INCLUDED ANY TSRA...BUT WILL MONITOR RADAR TRENDS CLOSELY. COLD
FRONT ON THU WILL AFFECT THE AREA IN THE AFTERNOON WITH A TIMEFRAME
AFTER THE VALID TIME OF THIS TAF. HOWEVER...SW WINDS WILL INCREASE
AHEAD OF THE FRONT PRIOR TO 18Z THU.
ELSEWHERE...MAIN QUESTION IS WHERE...IF ANY DEEP CONVECTION WILL
DEVELOP THIS AFTERNOON. LATEST HRRR AND HI-RES WRF INDICATE
CONVECTION DEVELOPING BY LATE AFTERNOON OVER THE WESTERN UPSTATE. AM
NOT CONFIDENT ENOUGH IN LOCATION TO ADD A TEMPO...BUT WILL ADD VCTS
TO THE KGMU...KGSP AND KAND TAFS. IT WILL THEN BE QUIET AND VFR
AFTER 00Z. A COLD FRONT WILL AFFECT THE AREA ON THU BUT AFTER
18Z. GUSTY SW WINDS WILL INCREASE AHEAD OF THE FRONT.
OUTLOOK...A COLD FRONT WILL BRING A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE REGION ON THURSDAY AFTERNOON WITH GUSTY WINDS
AND HAIL POSSIBLE.. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT AND
PRODUCE GENERALLY QUIET WEATHER AND VFR CONDITIONS THROUGH THE
WEEKEND.
CONFIDENCE TABLE...
20-02Z 02-08Z 08-14Z 14-20Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 88% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 94% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...VISIN
NEAR TERM...LG/RWH
SHORT TERM...JOH
LONG TERM...ARK/VISIN
AVIATION...LG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
244 PM EDT WED JUN 12 2013
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN WARM TEMPERATURES ACROSS THE REGION
TODAY AHEAD OF AN APPROACHING COLD FRONT...WHICH WILL CROSS THE AREA
ON THURSDAY. DRY HIGH PRESSURE WILL BUILD IN FROM THE NORTH
FRIDAY...MAKING FOR A MOSTLY DRY WEEKEND. THE NEXT COLD FRONT WILL
APPROACH THE REGION EARLY NEXT WEEK...TRIGGERING AFTERNOON SHOWERS
AND THUNDERSTORMS EACH DAY THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 230 PM...SPC MESOANAL PAGE SHOWS OVER 3000J/KG OF SBCAPE
ACROSS THE REGION WITH NO CIN. WILL CONTINUE THE IDEA PER HRRR/4KM
EMC WRF AND HI-RES WRF THAT SCT THUNDERSTORMS WILL DEVELOP OVER
THE WESTERN UPSTATE/NE GA BY LATE AFTERNOON TRIGGERED BY A MID
LEVEL VORT. THE ENTIRE AREA IS INCLUDED IN A SPC SLGT RISK AREA.
THIS MAKES SENSE IN THAT ANY STORMS THAT DEVELOP HAVE THE
POTENTIAL TO PRODUCE LOCALIZED DAMAGING WINDS PER THE 900J OF
DCAPE ANALYZED BY SPC. CONVECTION IS EXPECTED TO MOVE OUT OF THE
AREA BY 00Z.
THE OVERNIGHT SHOULD BE QUIET AS A WEAK RIDGE OF HIGH PRESSURE NOSES
EASTWARD INTO THE AREA. HOWEVER...WE WILL BE KEEPING AN EYE UPSTREAM
OVER THE LOWER GREAT LAKES WHERE A CONVECTIVE COMPLEX IS EXPECTED
TO DEVELOP AND PERHAPS TRANSITION INTO A DERECHO AS IT MOVES SE
THROUGH THE OHIO VALLEY AND INTO THE APPALACHIANS. THE 4KM EMC WRF
SHOWS THIS FEATURE MAKING A RUN AT THE NC MOUNTAINS LATE
TONIGHT...THEN DISSIPATING IT AS IT HITS THE MOUNTAINS. HAVE BUMPED
SOME CHC POPS UP TO ABOUT 12Z OVER THE NC BORDER COUNTIES TO ACCOUNT
FOR THIS. CAN`T RULE OUT SOME GUSTY WINDS REACHING THE AREA THU
MORNING FROM DERECHO OUTFLOW...BUT DO NOT HAVE THAT POSSIBILITY
CODED INTO THE GRIDS. IT WILL BE A WARM AND MUGGY NIGHT WITH LOWS
NOT GETTING OUT OF THE 70S FOR MOST AREAS EAST OF THE MOUNTAINS.
ON THU...A COLD FRONT IS STILL EXPECTED TO ARRIVE AND MOVE ACROSS
THE AREA DURING THE COURSE OF THE DAY. WIND FIELDS WILL BE IMPROVING
WITH 0-6KM BULK SHEAR INCREASING TO 35-40KT AND CAPES >2500J.
HENCE...SVR STORMS ARE CERTAINLY POSSIBLE PER THE SPC DAY 2 OUTLOOK.
LOOKS LIKE THE BEST THREAT FOR SEVERE STORMS WILL BE OVER THE
PIEDMONT IN THE MID TO LATE AFTERNOON HOURS. WINDS THROUGH THE
COLUMN WILL TAKE ON A DOWNSLOPE COMPONENT ON THU SO IT IS POSSIBLE
THAT COVERAGE ESPECIALLY ACROSS THE UPSTATE PERHAPS WILL NOT BE
100%. HENCE...POPS ARE HIGHEST ACROSS THE SOUTHERN PIEDMONT AREAS.
IT WILL BE ANOTHER HOT DAY ON THU WITH A MODEL BLEND PRODUCING HIGHS
IN THE 90-95 RANGE OUTSIDE THE MOUNTAINS AND MID 80S MOUNTAIN
VALLEYS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 130 PM EDT WEDNESDAY...EXPECT QUIET AND COOLER CONDITIONS FOR
THE SHORT TERM PERIOD. CONDITIONS QUICKLY DRY OUT THURSDAY EVENING
AS A SHARP UPPER TROUGH AXIS AND ASSOCIATED SURFACE COLD FRONT PUSH
EAST OF THE AREA. HOWEVER...SCATTERED LIGHT SHOWERS MAY CONTINUE
ACROSS THE NC MTNS THROUGH LATE THURSDAY NIGHT DUE TO INCREASING NW
UPSLOPE FLOW ALONG WITH THE PASSAGE OF WEAK UPPER DPVA THERE.
AN UPPER RIDGE OF H5 HIGH WILL REMAIN ANCHORED OVER THE SOUTHCENTRAL
STATES LEAVING OUR FORECAST AREA UNDER THE NW FLOW ALOFT FRI/SAT.
THIS WILL ALLOW CANADIAN SURFACE HIGH PRESSURE TO RIDGE SOUTH INTO
THE FORECAST AREA PROVIDING DRY NORTHERLY FLOW THROUGH THE PERIOD.
TEMPERATURES WILL BE AROUND 2-3 DEGREES BELOW NORMAL WITH HIGHS IN
THE LOWER TO MID 80S OVER THE PIEDMONT AND 70S IN THE HIGHER
TERRAIN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 2PM WEDNESDAY...THE MODELS REMAIN IN FAIRLY GOOD AGREEMENT
THROUGH MOST OF THE PERIOD. AFTER A PREDOMINANTLY DRY WEEKEND...THE
RIDGE OVER THE EASTERN CONUS WILL BREAK DOWN BY THE BEGINNING OF
NEXT WEEK. A WEAK TROUGH WILL THEN SET UP OVER THE SOUTHEASTERN
CONUS AND ALLOW A MORE UNSETTLED SUMMERTIME PATTERN TO RETURN. THE
NEXT FRONTAL SYSTEM APPROACHES LATE MONDAY/EARLY TUESDAY...RESULTING
IN DIURNAL CHANCE POPS FOR THE ENTIRE CWA ON MONDAY. THE FRONT
PASSES AND STALLS OUT JUST TO THE SOUTH OF THE FORECAST AREA LATE
TUESDAY...SO CHANCE POPS CONTINUE FOR THE ENTIRE FORECAST AREA
THROUGH MIDWEEK. TEMPERATURES WILL REMAIN NEAR NORMAL THROUGH THE
EXTENDED PERIOD.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...VFR THROUGH THE FORECAST PERIOD. SPC MESOANAL PAGE STILL
SHOWS SOME CONVECTIVE INHIBITION. ALSO...CONVECTION ALLOWING MODELS
SHOWING DEEP CONVECTION DEVELOPING WELL WEST OF THE AIRFIELD CLOSER
TO THE WEAK FORCING ASSOCIATED WITH A MID LEVEL VORT. HENCE...HAVE
NOT INCLUDED ANY TSRA...BUT WILL MONITOR RADAR TRENDS CLOSELY. COLD
FRONT ON THU WILL AFFECT THE AREA IN THE AFTERNOON WITH A TIMEFRAME
AFTER THE VALID TIME OF THIS TAF. HOWEVER...SW WINDS WILL INCREASE
AHEAD OF THE FRONT PRIOR TO 18Z THU.
ELSEWHERE...MAIN QUESTION IS WHERE...IF ANY DEEP CONVECTION WILL
DEVELOP THIS AFTERNOON. LATEST HRRR AND HI-RES WRF INDICATE
CONVECTION DEVELOPING BY LATE AFTERNOON OVER THE WESTERN UPSTATE. AM
NOT CONFIDENT ENOUGH IN LOCATION TO ADD A TEMPO...BUT WILL ADD VCTS
TO THE KGMU...KGSP AND KAND TAFS. IT WILL THEN BE QUIET AND VFR
AFTER 00Z. A COLD FRONT WILL AFFECT THE AREA ON THU BUT AFTER
18Z. GUSTY SW WINDS WILL INCREASE AHEAD OF THE FRONT.
OUTLOOK...A COLD FRONT WILL BRING A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE REGION ON THURSDAY AFTERNOON WITH GUSTY WINDS
AND HAIL POSSIBLE.. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT AND
PRODUCE GENERALLY QUIET WEATHER AND VFR CONDITIONS THROUGH THE
WEEKEND.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 95% HIGH 95%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 95% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...VISIN
NEAR TERM...LG
SHORT TERM...JOH
LONG TERM...VISIN
AVIATION...LG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
154 PM EDT WED JUN 12 2013
.SYNOPSIS...
WARM HIGH PRESSURE WILL BUILD ACROSS THE REGION TODAY...AHEAD OF AN
APPROACHING COLD FRONT...WHICH WILL CROSS THE AREA ON THURSDAY. DRY
HIGH PRESSURE WILL BUILD IN FROM THE NORTH FRIDAY THROUGH THE
WEEKEND. ANOTHER COLD FRONT WILL APPROACH THE REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 145 PM...LOOKS LIKE CONVECTIVE INHIBITION HAS BEEN ERODED AWAY
PER SPC MESOANAL PAGE WITH OVER 3000J/KG OF SBCAPE NOW ACROSS THE
REGION. A BETTER CASE CAN NOW BE MADE FOR INCREASING THE CHC FOR
THUNDERSTORMS...ESPECIALLY IN LIGHT THAT SPC HAS NOW INCLUDED THE
AREA IN A SLIGHT RISK. LATEST HRRR AND HI-RES WRF DEVELOP SCT
CONVECTION MAINLY ACROSS THE WESTERN UPSTATE/NE GA CLOSER TO THE
WEAK LIFT PROVIDED BY A PASSING MID LEVEL VORT. HENCE...HAVE UPPED
POPS INTO THE SCT RANGE FROM ABOUT GREENVILLE WESTWARD. ANY STORMS
THAT DEVELOP HAVE THE POTENTIAL TO PRODUCE LOCALIZED DAMAGING WINDS
PER THE 900J OF DCAPE ANALYZED BY SPC.
AS OF 0955 AM...CURRENT RADAR TRENDS AND LATEST HRRR SUGGEST THAT WE
SHOULD BACK OFF ON THE IDEA THAT A CONVECTIVE COMPLEX WILL MOVE SE
ACROSS THE AREA OUT OF WV AND ACROSS THE FORECAST AREA THIS
AFTERNOON. PREVIOUS CONVECTION OVER WV HAS WANED AS IT MOVED SE INTO
A MORE STABLE AIRMASS. IN FACT...FORECAST SOUNDINGS AS MENTIONED
PREVIOUSLY LOOK CAPPED WITH CONSIDERABLE LOW LEVEL CIN. WILL HAVE
THE HIGHEST POPS OVER THE FAR EASTERN NC PIEDMONT WHERE SOME STORMS
CAN`T BE RULED OUT AND OVER THE FAR WEST...IN NE GA AND WESTERN
UPSTATE WHERE THE 06Z NAM HAD SOME QPF RESPONSE. ALSO ADJUSTED
TEMPS/DEWPOINTS/WINDS BASED ON LATEST TRENDS AND LAMP DATA. SOME
SOME LIGHT WIDELY SCATTERED LIGHT SHOWERS SHOWING UP ON RADAR ACROSS
THE WESTERN UPSTATE PROBABLY IN ASSOCIATION WITH A PASSAGE OF A MID
LEVEL VORT CENTER PER NAM/GFS. HAVE SOME WIDELY SCATTERED POPS EARLY
TO HANDLE THOSE.
PREVIOUS DISCUSSION:
AS OF 730 AM...CURRENT FORECAST TRENDS LOOK GOOD. MAIN FORECAST
PROBLEM IS WHETHER ANY SIGNIFICANT DEEP CONVECTION WILL OCCUR.
FORECAST SOUNDINGS LOOK CAPPED ALL DAY WITH CONSIDERABLE LOW LEVEL
CIN...BUT SOME CONVECTION ALLOWING MODELS LIKE THE EMC WRF AND
HI-RES WRF TAKE THE CURRENT CONVECTION OVER WV SE AND AND DEVELOP A
MCS WHICH PLOWS THROUGH THE AREA THIS AFTERNOON. HOWEVER...LATEST
HRRR AND LOCAL WRF ARE MUTED AND WEAKEN THE CONVECTION AS IT MOVES
SE INTO THE CURRENTLY MUCH LESS STABLE ENVIRONMENT AS DEPICTED BY
SPC MESOANAL PAGE. LOW END CHC POPS ARE CURRENTLY IN THE GRIDS AND
THAT LOOKS FINE FOR NOW. WILL EVALUATE TRENDS AND TRY TO FINE TUNE
FORECAST LATER THIS MORNING. A FEW LIGHT SHRA HAVE SHOWN UP ON RADAR
ACROSS THE NORTHERN UPSTATE FALLIGN OUT OF A MID LEVEL DECK. HAVFE
ADDED SOME WIDELY SCT POPS TO HANDLE THAT. EXPECT THOSE SHRA TO
DISSIPATE THIS MORNING.
PREVIOUS DISCUSSION...
FOR TODAY...A COUPLE OF INTERESTING THINGS TO DISCUSS. OVERALL...
THE WESTERN CAROLINAS WILL BE UNDER A NW FLOW ALOFT WITH THE
POTENTIAL FOR MESOSCALE VORT CENTERS TO MOVE DOWN ACROSS THE REGION.
WEAK HIGH PRESSURE AT THE SURFACE WILL NOSE IN FROM THE SOUTHWEST.
EXPECTED THE MAIN STORY TO BE THE HEAT...WITH GUIDANCE FOR THE LAST
SEVERAL DAYS SHOWING UPPER 90S E OF THE MTNS...OWING TO DOWNSLOPE
FLOW AND A STRONG CAPPING INVERSION. HOWEVER...QUICK DOWNWARD TREND
HAS DEVELOPED IN THE GUIDANCE...WHICH SEEMS REASONABLE GIVEN THE
AMOUNT OF MID AND HIGH LEVEL CONVECTIVE DEBRIS EXPECTED INTO THE MID
AFTERNOON. OUR FCST HIGHS ARE MUCH MORE IN LINE WITH A GUIDANCE
BLEND SO THERE IS LITTLE CHANGE FROM THE PREVIOUS FCST IN THAT
REGARD. PREVIOUS THOUGHTS WERE ALSO THAT DEEP CONVECTION WOULD BE
HIGHLY DISCOURAGED DUE TO A FORMIDABLE CAPPING INVERSION. THE NEW
GUIDANCE SUGGESTS THAT IT MIGHT NOT BE SO UNBREAKABLE LATE IN THE
AFTERNOON. SOME OF THE CONVECTION ALLOWING MODELS DEVELOP A
THUNDERSTORM COMPLEX OVER THE CENTRAL APPALACHIANS THIS AFTERNOON
THAT PLOWS SOUTHWARD ACROSS THE PIEDMONT OF THE CAROLINAS THROUGH
EARLY EVENING. IF THAT WERE TO HAPPEN...THERE WOULD BE ENOUGH
DOWNDRAFT CAPE FOR SEVERAL SWATHS OF WIND DAMAGE. THE GFS IS STILL
BASICALLY DRY AND CAPPED...BUT THE NAM SUGGESTS NUMEROUS STORMS. IT
SEEMS THE MOST LIKELY SCENARIO IS FOR STORM COVERAGE TO REMAIN
LIMITED BECAUSE OF THE CAP THAT MIGHT NOT BE OVERCOME UNTIL AFTER
21Z...BUT WARY OF ANY BLOWUP OF CONVECTION OVER SRN WV/SW VA...THAT
WOULD REQUIRE A QUICK OVERHAUL OF PRECIP CHANCES. THE CONVECTION IF
IT DEVELOPS WILL MOVE OFF TO THE S IN THE MID EVENING. THEN
ATTENTION TURNS TO THE NEXT POSSIBLE UPSTREAM MCS APPROACHING FROM
THE NW TOWARD DAYBREAK THURSDAY. AT THIS POINT...IT APPEARS THAT IT
WOULD NOT REACH THE MTNS BEFORE SUNRISE...SO THE POP WILL BE KEPT
LOW AT THE VERY END OF THE PERIOD.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AS OF 130 PM EDT WEDNESDAY...EXPECT QUIET AND COOLER CONDITIONS FOR
THE SHORT TERM PERIOD. CONDITIONS QUICKLY DRY OUT THURSDAY NIGHT AS
A SHARP UPPER TROUGH AXIS AND ASSOCIATED SURFACE COLD FRONT PUSH
EAST OF THE AREA. HOWEVER...LIGHT UPSLOPE SHOWERS CAN BE SEEN ALONG
THE TN BORDER THROUGH EARLY FRI MORNING DUE TO INCREASING LLVL NW
FLOW ALONG WITH THE PASSAGE OF WEAK UPPER DPVA THERE.
AN UPPER RIDGE OF H5 HIGH WILL REMAIN ANCHORED OVER THE SOUTHCENTRAL
STATES LEAVING OUR FORECAST AREA UNDER THE NW FLOW ALOFT FRI/SAT.
THIS WILL ALLOW CANADIAN SURFACE HIGH PRESSURE TO RIDGE SOUTH INTO
THE FORECAST AREA PROVIDING DRY NORTHERLY FLOW THROUGH THE PERIOD.
TEMPERATURES WILL BE AROUND 2-3 DEGREES BELOW NORMAL WITH HIGHS IN
THE LOWER TO MID 80S OVER THE PIEDMONT AND 70S IN THE HIGHER
TERRAIN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...MODELS IN GOOD AGREEMENT ON THE SRN CONUS
UPR RIDGE BREAKING DOWN SOMEWHAT BY THE END OF THE WEEKEND...WITH A
RETURN OF WLY UPR FLOW AND THE SHORTWAVE TRACK OVER THE CWFA FOR
EARLY NEXT WEEK. THE RIDGE WILL RE-ESTABLISH OVER THE SRN PLAINS BY
MIDWEEK...KEEPING THE ERN STATES IN PERSISTENT UPR TROFINESS. THIS
WILL LIKELY RESULT IN UNSETTLED WX RETURNING TO THE AREA FOR NEXT
WEEK...WITH SLIGHTLY ABOVE NORMAL TEMPS.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...VFR THROUGH THE FORECAST PERIOD. SPC MESOANAL PAGE STILL
SHOWS SOME CONVECTIVE INHIBITION. ALSO...CONVECTION ALLOWING MODELS
SHOWING DEEP CONVECTION DEVELOPING WELL WEST OF THE AIRFIELD CLOSER
TO THE WEAK FORCING ASSOCIATED WITH A MID LEVEL VORT. HENCE...HAVE
NOT INCLUDED ANY TSRA...BUT WILL MONITOR RADAR TRENDS CLOSELY. COLD
FRONT ON THU WILL AFFECT THE AREA IN THE AFTERNOON WITH A TIMEFRAME
AFTER THE VALID TIME OF THIS TAF. HOWEVER...SW WINDS WILL INCREASE
AHEAD OF THE FRONT PRIOR TO 18Z THU.
ELSEWHERE...MAIN QUESTION IS WHERE...IF ANY DEEP CONVECTION WILL
DEVELOP THIS AFTERNOON. LATEST HRRR AND HI-RES WRF INDICATE
CONVECTION DEVELOPING BY LATE AFTERNOON OVER THE WESTERN UPSTATE. AM
NOT CONFIDENT ENOUGH IN LOCATION TO ADD A TEMPO...BUT WILL ADD VCTS
TO THE KGMU...KGSP AND KAND TAFS. IT WILL THEN BE QUIET AND VFR
AFTER 00Z. A COLD FRONT WILL AFFECT THE AREA ON THU BUT AFTER
18Z. GUSTY SW WINDS WILL INCREASE AHEAD OF THE FRONT.
OUTLOOK...A COLD FRONT WILL BRING A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE REGION ON THURSDAY AFTERNOON WITH GUSTY WINDS
AND HAIL POSSIBLE.. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT AND
PRODUCE GENERALLY QUIET WEATHER AND VFR CONDITIONS THROUGH THE
WEEKEND.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 95% HIGH 95%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 95% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...ARK
NEAR TERM...LG
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...PM
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
954 AM EDT WED JUN 12 2013
.SYNOPSIS...
WARM HIGH PRESSURE WILL BUILD ACROSS THE REGION TODAY...AHEAD OF AN
APPROACHING COLD FRONT...WHICH WILL CROSS THE AREA ON THURSDAY. DRY
HIGH PRESSURE WILL BUILD IN FROM THE NORTH FRIDAY THROUGH THE
WEEKEND. ANOTHER COLD FRONT WILL APPROACH THE REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 0955 AM...CURRENT RADAR TRENDS AND LATEST HRRR SUGGEST THAT WE
SHOULD BACK OFF ON THE IDEA THAT A CONVECTIVE COMPLEX WILL MOVE SE
ACROSS THE AREA OUT OF WV AND ACROSS THE FORECAST AREA THIS
AFTERNOON. PREVIOUS CONVECTION OVER WV HAS WANED AS IT MOVED SE INTO
A MORE STABLE AIRMASS. IN FACT...FORECAST SOUNDINGS AS MENTIONED
PREVIOUSLY LOOK CAPPED WITH CONSIDERABLE LOW LEVEL CIN. WILL HAVE
THE HIGHEST POPS OVER THE FAR EASTERN NC PIEDMONT WHERE SOME STORMS
CAN`T BE RULED OUT AND OVER THE FAR WEST...IN NE GA AND WESTERN
UPSTATE WHERE THE 06Z NAM HAD SOME QPF RESPONSE. ALSO ADJUSTED
TEMPS/DEWPOINTS/WINDS BASED ON LATEST TRENDS AND LAMP DATA. SOME
SOME LIGHT WIDELY SCATTERED LIGHT SHOWERS SHOWING UP ON RADAR ACROSS
THE WESTERN UPSTATE PROBABLY IN ASSOCIATION WITH A PASSAGE OF A MID
LEVEL VORT CENTER PER NAM/GFS. HAVE SOME WIDELY SCATTERED POPS EARLY
TO HANDLE THOSE.
PREVIOUS DISCUSSION:
AS OF 730 AM...CURRENT FORECAST TRENDS LOOK GOOD. MAIN FORECAST
PROBLEM IS WHETHER ANY SIGNIFICANT DEEP CONVECTION WILL OCCUR.
FORECAST SOUNDINGS LOOK CAPPED ALL DAY WITH CONSIDERABLE LOW LEVEL
CIN...BUT SOME CONVECTION ALLOWING MODELS LIKE THE EMC WRF AND
HI-RES WRF TAKE THE CURRENT CONVECTION OVER WV SE AND AND DEVELOP A
MCS WHICH PLOWS THROUGH THE AREA THIS AFTERNOON. HOWEVER...LATEST
HRRR AND LOCAL WRF ARE MUTED AND WEAKEN THE CONVECTION AS IT MOVES
SE INTO THE CURRENTLY MUCH LESS STABLE ENVIRONMENT AS DEPICTED BY
SPC MESOANAL PAGE. LOW END CHC POPS ARE CURRENTLY IN THE GRIDS AND
THAT LOOKS FINE FOR NOW. WILL EVALUATE TRENDS AND TRY TO FINE TUNE
FORECAST LATER THIS MORNING. A FEW LIGHT SHRA HAVE SHOWN UP ON RADAR
ACROSS THE NORTHERN UPSTATE FALLIGN OUT OF A MID LEVEL DECK. HAVFE
ADDED SOME WIDELY SCT POPS TO HANDLE THAT. EXPECT THOSE SHRA TO
DISSIPATE THIS MORNING.
PREVIOUS DISCUSSION...
FOR TODAY...A COUPLE OF INTERESTING THINGS TO DISCUSS. OVERALL...
THE WESTERN CAROLINAS WILL BE UNDER A NW FLOW ALOFT WITH THE
POTENTIAL FOR MESOSCALE VORT CENTERS TO MOVE DOWN ACROSS THE REGION.
WEAK HIGH PRESSURE AT THE SURFACE WILL NOSE IN FROM THE SOUTHWEST.
EXPECTED THE MAIN STORY TO BE THE HEAT...WITH GUIDANCE FOR THE LAST
SEVERAL DAYS SHOWING UPPER 90S E OF THE MTNS...OWING TO DOWNSLOPE
FLOW AND A STRONG CAPPING INVERSION. HOWEVER...QUICK DOWNWARD TREND
HAS DEVELOPED IN THE GUIDANCE...WHICH SEEMS REASONABLE GIVEN THE
AMOUNT OF MID AND HIGH LEVEL CONVECTIVE DEBRIS EXPECTED INTO THE MID
AFTERNOON. OUR FCST HIGHS ARE MUCH MORE IN LINE WITH A GUIDANCE
BLEND SO THERE IS LITTLE CHANGE FROM THE PREVIOUS FCST IN THAT
REGARD. PREVIOUS THOUGHTS WERE ALSO THAT DEEP CONVECTION WOULD BE
HIGHLY DISCOURAGED DUE TO A FORMIDABLE CAPPING INVERSION. THE NEW
GUIDANCE SUGGESTS THAT IT MIGHT NOT BE SO UNBREAKABLE LATE IN THE
AFTERNOON. SOME OF THE CONVECTION ALLOWING MODELS DEVELOP A
THUNDERSTORM COMPLEX OVER THE CENTRAL APPALACHIANS THIS AFTERNOON
THAT PLOWS SOUTHWARD ACROSS THE PIEDMONT OF THE CAROLINAS THROUGH
EARLY EVENING. IF THAT WERE TO HAPPEN...THERE WOULD BE ENOUGH
DOWNDRAFT CAPE FOR SEVERAL SWATHS OF WIND DAMAGE. THE GFS IS STILL
BASICALLY DRY AND CAPPED...BUT THE NAM SUGGESTS NUMEROUS STORMS. IT
SEEMS THE MOST LIKELY SCENARIO IS FOR STORM COVERAGE TO REMAIN
LIMITED BECAUSE OF THE CAP THAT MIGHT NOT BE OVERCOME UNTIL AFTER
21Z...BUT WARY OF ANY BLOWUP OF CONVECTION OVER SRN WV/SW VA...THAT
WOULD REQUIRE A QUICK OVERHAUL OF PRECIP CHANCES. THE CONVECTION IF
IT DEVELOPS WILL MOVE OFF TO THE S IN THE MID EVENING. THEN
ATTENTION TURNS TO THE NEXT POSSIBLE UPSTREAM MCS APPROACHING FROM
THE NW TOWARD DAYBREAK THURSDAY. AT THIS POINT...IT APPEARS THAT IT
WOULD NOT REACH THE MTNS BEFORE SUNRISE...SO THE POP WILL BE KEPT
LOW AT THE VERY END OF THE PERIOD.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AS OF 245 AM WEDNESDAY...MODELS HAVE BEEN TRENDING A LITTLE BIT
SLOWER AND DEEPER WITH A SFC LOW...AS IT RACES ACRS PA INTO THE NRN
MID ATLANTIC COASTAL WATERS ON THURSDAY. THE BEST UPPER FORCING
LOOKS TO BE NEAR THIS SFC LOW...WHILE THE BEST INSTBY WILL BE OVER
THE TN VALLEY AND NRN GULF STATES. THE RESULT IS FOR A SORT OF GSP
SPLIT IN THE QPF RESPONSE...AND HENCE PERHAPS LESS OF A SEVERE
THREAT THAN EARLIER ANTICIPATED. THE ENVIRONMENT STILL LOOKS
FAVORABLE FOR SEVERE STORMS...MAINLY DURING THE AFTN HOURS AS A
FRONTAL BAND DEVELOPS/INTENSIFIES JUST OFF THE BLUE RIDGE AND
CROSSES THE PIEDMONT. STILL LOOKING AT 2000+ J/KG OF CAPE EAST OF
THE MTNS WITH BULK SHEAR OF 25-35 KTS. THE NEW DAY 2 CONVECTIVE
OUTLOOK KEEPS THE AREA IN A SLGT RISK...WITH A MODERATE RISK FOR
MORE WIDESPREAD WIND DAMAGE TO OUR NE CLOSER TO THE SFC LOW. WILL
ONLY MAKE MINOR TWEAKS TO THE HWO WORDING THIS MORNING. TEMPS WILL
PROBABLY BE ABLE TO WARM UP INTO THE LWR-MID 90S AHEAD OF THE
FRONT/CONVECTION EAST OF THE MTNS.
THE LINE OF CONVECTION AND COLD FRONT SHUD PUSH THRU THE SE CORNER
OF THE CWFA BY LATE EVENING...WITH DRY HIGH PRES BUILDING IN FOR
FRIDAY AND SATURDAY. POPS TAPER OFF THURSDAY EVENING...AND REMAIN
BELOW 15% THRU SATURDAY. TEMPS RETURN TO NEAR OR SLIGHTLY BELOW
NORMAL READINGS WITH A NOTICEABLE DROP IN HUMIDITY TOO.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...MODELS IN GOOD AGREEMENT ON THE SRN CONUS
UPR RIDGE BREAKING DOWN SOMEWHAT BY THE END OF THE WEEKEND...WITH A
RETURN OF WLY UPR FLOW AND THE SHORTWAVE TRACK OVER THE CWFA FOR
EARLY NEXT WEEK. THE RIDGE WILL RE-ESTABLISH OVER THE SRN PLAINS BY
MIDWEEK...KEEPING THE ERN STATES IN PERSISTENT UPR TROFINESS. THIS
WILL LIKELY RESULT IN UNSETTLED WX RETURNING TO THE AREA FOR NEXT
WEEK...WITH SLIGHTLY ABOVE NORMAL TEMPS.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...VFR THROUGH THE FORECAST PERIOD. THE FCST SOUNDINGS FROM
MOST MODELS ARE CAPPED...SO ONLY A FEW HIGH BASED STRATOCU ARE
EXPECTED THROUGH MOST OF THE AFTERNOON...UNDERNEATH SOME MID AND
HIGH LEVEL CONVECTIVE DEBRIS MOVING DOWN FROM THE NW. WIND SHOULD
COME AROUND TO WSW BECAUSE OF A LEE TROF BY LATE MORNING. AND NOW HERE IS
THE CAVEAT...SOME OF THE CONVECTION ALLOWING MODELS SUGGEST A
COMPLEX OF THUNDERSTORMS WILL DEVELOP OVER SRN WV AND THEN PLOW
SOUTHWARD ACROSS THE PIEDMONT OF NC IN THE AFTERNOON...PERHAPS WITH
DECENT POTENTIAL FOR DAMAGING WIND GUSTS AND LARGE HAIL. IN THAT
CASE...THE CAP WOULD WORK TO THE ADVANTAGE OF THE STORMS BY HOLDING
THE LID ON THE DEEP CONVECTION AND STORING UP ALL THE ENERGY UNTIL
THE SQUALL LINE ARRIVES TO RELEASE IT. THIS IS ALL CONJECTURE.
RECENT RADAR IMAGERY SUGGESTS THIS MIGHT COME TO FRUITION. FOR NOW
THIS WILL BE INDICATED WITH A PROB30 FOR TSRA IN THE 21Z TO 23Z TIME
FRAME. WILL TRY TO GET A BETTER HANDLE ON THE CONVECTIVE THREAT THIS
MORNING. THE EVENING SHOULD BECOME UNEVENTFUL WITH LIGHT WIND AFTER
SUNSET.
ELSEWHERE...EXPECT MAINLY INCREASING HIGH LEVEL CLOUDS FROM MCS
DEBRIS THROUGH MORNING. THERE COULD BE SOME MVFR VISIBILITY IN THE
VICINITY OF KAVL AROUND SUNRISE. FOR THE AFTERNOON...SCENARIO IS
SIMILAR TO KCLT E OF THE BLUE RIDGE...WITH ISOLATED THUNDERSTORMS
POSSIBLE...BUT WILL NOT MENTION AT THIS TIME.
OUTLOOK...A COLD FRONT WILL BRING A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE REGION ON THURSDAY. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT AND PRODUCE GENERALLY QUIET WEATHER AND VFR
CONDITIONS THROUGH THE WEEKEND.
CONFIDENCE TABLE...
14-20Z 20-02Z 02-08Z 08-14Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...ARK
NEAR TERM...LG
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...PM
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
806 AM EDT WED JUN 12 2013
.SYNOPSIS...
WARM HIGH PRESSURE WILL BUILD ACROSS THE REGION TODAY...AHEAD OF AN
APPROACHING COLD FRONT...WHICH WILL CROSS THE AREA ON THURSDAY. DRY
HIGH PRESSURE WILL BUILD IN FROM THE NORTH FRIDAY THROUGH THE
WEEKEND. ANOTHER COLD FRONT WILL APPROACH THE REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 8 AM...CURRENT FORECAST TRENDS LOOK PRETTY GOOD. MAIN
FORECAST PROBLEM IS WHETHER ANY SIGNIFICANT DEEP CONVECTION WILL
OCCUR. FORECAST SOUNDINGS LOOK CAPPED ALL DAY WITH CONSIDERABLE
LOW LEVEL CIN...BUT SOME CONVECTION ALLOWING MODELS LIKE THE EMC
WRF AND HI- RES WRF TAKE THE CURRENT CONVECTION OVER WV SE AND AND
DEVELOP A MCS WHICH PLOWS THROUGH THE AREA THIS AFTERNOON.
HOWEVER...LATEST HRRR AND LOCAL WRF ARE MUTED AND WEAKEN THE
CONVECTION AS IT MOVES SE INTO THE CURRENTLY MUCH LESS STABLE
ENVIRONMENT AS DEPICTED BY SPC MESOANAL PAGE. LOW END CHC POPS ARE
CURRENTLY IN THE GRIDS AND THAT LOOKS FINE FOR NOW. WILL EVALUATE
TRENDS AND TRY TO FINE TUNE FORECAST LATER THIS MORNING. A FEW
LIGHT SHRA HAVE SHOWN UP ON RADAR ACROSS THE NORTHERN UPSTATE
FALLIGN OUT OF A MID LEVEL DECK. HAVFE ADDED SOME WIDELY SCT POPS
TO HANDLE THAT. EXPECT THOSE SHRA TO DISSIPATE THIS MORNING.
PREVIOUS DISCUSSION...
FOR TODAY...A COUPLE OF INTERESTING THINGS TO DISCUSS. OVERALL...
THE WESTERN CAROLINAS WILL BE UNDER A NW FLOW ALOFT WITH THE
POTENTIAL FOR MESOSCALE VORT CENTERS TO MOVE DOWN ACROSS THE REGION.
WEAK HIGH PRESSURE AT THE SURFACE WILL NOSE IN FROM THE SOUTHWEST.
EXPECTED THE MAIN STORY TO BE THE HEAT...WITH GUIDANCE FOR THE LAST
SEVERAL DAYS SHOWING UPPER 90S E OF THE MTNS...OWING TO DOWNSLOPE
FLOW AND A STRONG CAPPING INVERSION. HOWEVER...QUICK DOWNWARD TREND
HAS DEVELOPED IN THE GUIDANCE...WHICH SEEMS REASONABLE GIVEN THE
AMOUNT OF MID AND HIGH LEVEL CONVECTIVE DEBRIS EXPECTED INTO THE MID
AFTERNOON. OUR FCST HIGHS ARE MUCH MORE IN LINE WITH A GUIDANCE
BLEND SO THERE IS LITTLE CHANGE FROM THE PREVIOUS FCST IN THAT
REGARD. PREVIOUS THOUGHTS WERE ALSO THAT DEEP CONVECTION WOULD BE
HIGHLY DISCOURAGED DUE TO A FORMIDABLE CAPPING INVERSION. THE NEW
GUIDANCE SUGGESTS THAT IT MIGHT NOT BE SO UNBREAKABLE LATE IN THE
AFTERNOON. SOME OF THE CONVECTION ALLOWING MODELS DEVELOP A
THUNDERSTORM COMPLEX OVER THE CENTRAL APPALACHIANS THIS AFTERNOON
THAT PLOWS SOUTHWARD ACROSS THE PIEDMONT OF THE CAROLINAS THROUGH
EARLY EVENING. IF THAT WERE TO HAPPEN...THERE WOULD BE ENOUGH
DOWNDRAFT CAPE FOR SEVERAL SWATHS OF WIND DAMAGE. THE GFS IS STILL
BASICALLY DRY AND CAPPED...BUT THE NAM SUGGESTS NUMEROUS STORMS. IT
SEEMS THE MOST LIKELY SCENARIO IS FOR STORM COVERAGE TO REMAIN
LIMITED BECAUSE OF THE CAP THAT MIGHT NOT BE OVERCOME UNTIL AFTER
21Z...BUT WARY OF ANY BLOWUP OF CONVECTION OVER SRN WV/SW VA...THAT
WOULD REQUIRE A QUICK OVERHAUL OF PRECIP CHANCES. THE CONVECTION IF
IT DEVELOPS WILL MOVE OFF TO THE S IN THE MID EVENING. THEN
ATTENTION TURNS TO THE NEXT POSSIBLE UPSTREAM MCS APPROACHING FROM
THE NW TOWARD DAYBREAK THURSDAY. AT THIS POINT...IT APPEARS THAT IT
WOULD NOT REACH THE MTNS BEFORE SUNRISE...SO THE POP WILL BE KEPT
LOW AT THE VERY END OF THE PERIOD.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AS OF 245 AM WEDNESDAY...MODELS HAVE BEEN TRENDING A LITTLE BIT
SLOWER AND DEEPER WITH A SFC LOW...AS IT RACES ACRS PA INTO THE NRN
MID ATLANTIC COASTAL WATERS ON THURSDAY. THE BEST UPPER FORCING
LOOKS TO BE NEAR THIS SFC LOW...WHILE THE BEST INSTBY WILL BE OVER
THE TN VALLEY AND NRN GULF STATES. THE RESULT IS FOR A SORT OF GSP
SPLIT IN THE QPF RESPONSE...AND HENCE PERHAPS LESS OF A SEVERE
THREAT THAN EARLIER ANTICIPATED. THE ENVIRONMENT STILL LOOKS
FAVORABLE FOR SEVERE STORMS...MAINLY DURING THE AFTN HOURS AS A
FRONTAL BAND DEVELOPS/INTENSIFIES JUST OFF THE BLUE RIDGE AND
CROSSES THE PIEDMONT. STILL LOOKING AT 2000+ J/KG OF CAPE EAST OF
THE MTNS WITH BULK SHEAR OF 25-35 KTS. THE NEW DAY 2 CONVECTIVE
OUTLOOK KEEPS THE AREA IN A SLGT RISK...WITH A MODERATE RISK FOR
MORE WIDESPREAD WIND DAMAGE TO OUR NE CLOSER TO THE SFC LOW. WILL
ONLY MAKE MINOR TWEAKS TO THE HWO WORDING THIS MORNING. TEMPS WILL
PROBABLY BE ABLE TO WARM UP INTO THE LWR-MID 90S AHEAD OF THE
FRONT/CONVECTION EAST OF THE MTNS.
THE LINE OF CONVECTION AND COLD FRONT SHUD PUSH THRU THE SE CORNER
OF THE CWFA BY LATE EVENING...WITH DRY HIGH PRES BUILDING IN FOR
FRIDAY AND SATURDAY. POPS TAPER OFF THURSDAY EVENING...AND REMAIN
BELOW 15% THRU SATURDAY. TEMPS RETURN TO NEAR OR SLIGHTLY BELOW
NORMAL READINGS WITH A NOTICEABLE DROP IN HUMIDITY TOO.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...MODELS IN GOOD AGREEMENT ON THE SRN CONUS
UPR RIDGE BREAKING DOWN SOMEWHAT BY THE END OF THE WEEKEND...WITH A
RETURN OF WLY UPR FLOW AND THE SHORTWAVE TRACK OVER THE CWFA FOR
EARLY NEXT WEEK. THE RIDGE WILL RE-ESTABLISH OVER THE SRN PLAINS BY
MIDWEEK...KEEPING THE ERN STATES IN PERSISTENT UPR TROFINESS. THIS
WILL LIKELY RESULT IN UNSETTLED WX RETURNING TO THE AREA FOR NEXT
WEEK...WITH SLIGHTLY ABOVE NORMAL TEMPS.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...VFR THROUGH THE FORECAST PERIOD. THE FCST SOUNDINGS FROM
MOST MODELS ARE CAPPED...SO ONLY A FEW HIGH BASED STRATOCU ARE
EXPECTED THROUGH MOST OF THE AFTERNOON...UNDERNEATH SOME MID AND
HIGH LEVEL CONVECTIVE DEBRIS MOVING DOWN FROM THE NW. WIND SHOULD
COME AROUND TO WSW BECAUSE OF A LEE TROF BY LATE MORNING. AND NOW HERE IS
THE CAVEAT...SOME OF THE CONVECTION ALLOWING MODELS SUGGEST A
COMPLEX OF THUNDERSTORMS WILL DEVELOP OVER SRN WV AND THEN PLOW
SOUTHWARD ACROSS THE PIEDMONT OF NC IN THE AFTERNOON...PERHAPS WITH
DECENT POTENTIAL FOR DAMAGING WIND GUSTS AND LARGE HAIL. IN THAT
CASE...THE CAP WOULD WORK TO THE ADVANTAGE OF THE STORMS BY HOLDING
THE LID ON THE DEEP CONVECTION AND STORING UP ALL THE ENERGY UNTIL
THE SQUALL LINE ARRIVES TO RELEASE IT. THIS IS ALL CONJECTURE.
RECENT RADAR IMAGERY SUGGESTS THIS MIGHT COME TO FRUITION. FOR NOW
THIS WILL BE INDICATED WITH A PROB30 FOR TSRA IN THE 21Z TO 23Z TIME
FRAME. WILL TRY TO GET A BETTER HANDLE ON THE CONVECTIVE THREAT THIS
MORNING. THE EVENING SHOULD BECOME UNEVENTFUL WITH LIGHT WIND AFTER
SUNSET.
ELSEWHERE...EXPECT MAINLY INCREASING HIGH LEVEL CLOUDS FROM MCS
DEBRIS THROUGH MORNING. THERE COULD BE SOME MVFR VISIBILITY IN THE
VICINITY OF KAVL AROUND SUNRISE. FOR THE AFTERNOON...SCENARIO IS
SIMILAR TO KCLT E OF THE BLUE RIDGE...WITH ISOLATED THUNDERSTORMS
POSSIBLE...BUT WILL NOT MENTION AT THIS TIME.
OUTLOOK...A COLD FRONT WILL BRING A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE REGION ON THURSDAY. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT AND PRODUCE GENERALLY QUIET WEATHER AND VFR
CONDITIONS THROUGH THE WEEKEND.
CONFIDENCE TABLE...
12-18Z 18-24Z 00-06Z 06-12Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...ARK
NEAR TERM...LG/PAT
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...PM
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
157 AM EDT WED JUN 12 2013
.SYNOPSIS...
WARM HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY BEFORE A
COLD FRONT AFFECTS THE AREA ON THURSDAY. DRY HIGH PRESSURE WILL
BUILD IN FROM THE NORTH FRIDAY AND SATURDAY AND KEEP THE WEATHER DRY
OVER MOST OF THE THE WEEKEND. ANOTHER COLD FRONT WILL APPROACH THE
REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF THE EARLY MORNING HOURS...ALL IS QUIET. NOTHING GOING ON
UPSTREAM TO SPEAK OF. NO BIG CHANGES.
PREVIOUS DISCUSSION...
AS OF 1030 PM EDT...RADARS REMAIN FAIRLY QUIET UPSTREAM IN THE WEAK
MCS GENESIS REGION ACROSS THE OH VALLEY. HOWEVER...BOTH THE INCOMING
00Z NAM AND THE LATEST HRRR RUN INDICATE CONVECTIVE DEVELOPMENT OVER
SRN OH CIRCA 08Z TO 09Z...AND THIS ACTIVITY COULD WELL MAKE A RUN TO
THE SPINE OF THE SRN APPALACHIANS BEFORE 12Z. WILL THUS CONTINUE TO
FEATURE LOW END CHC POPS ALONG THE TN BORDER STARTING AROUND
DAYBREAK...WITH SCT COVERAGE POSSIBLY SURVIVING INTO THE FOOTHILLS
THROUGH LATE WED MORNING. MODEL PROFILES STILL EXHIBIT QUITE A BIT
OF LOW LEVEL CIN EAST OF THE MTNS...SO WILL KEEP POPS CAPPED AT
SLIGHT CHANCE FOR THE SE HALF THROUGH WED.
LOW LEVEL THICKNESSES SUPPORT MAX TEMPS IN THE MID 90S OVER MUCH OF
THE PIEDMONT WED AFTN. HOWEVER...EXPECT THAT SOME DEBRIS CLOUDS WILL
BE AROUND THROUGH AT LEAST MIDDAY WHICH WILL SLOW DOWN THE WARMING.
EVEN SO...A GUIDANCE BLEND SUPORTS MAX TEMPS IN THE LOW 90S OVER
MUCH OF THE PIEDMONT...WITH MID 80S IN THE MOUNTAIN VALLEYS.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
AS OF 245 PM TUESDAY...SHORT RANGE MODELS AGREE THAT THE CENTER OF SFC
LOW PRESSURE WILL TRACK NE ACROSS THE NORTHERN OHIO RIVER VALLEY BY
12Z THURSDAY. AT H5...THE AXIS OF MID LEVEL TROF IS EXPECTED TO
RIPPLE FROM THE OHIO RIVER VALLEY ACROSS THE NC MTNS BY 21Z THURS.
AT THE SFC...A COLD FRONT ASSOCIATED WITH THE NRN LOW PRESSURE WILL
SWEEP ACROSS THE NC MTNS DURING THE EARLY AFTERNOON. THE TIMING OF
THE SFC FRONT AND MID LEVEL WAVE WILL FALL DURING PRIME DIURNAL TIME
FOR DEEP CONVECTION. NAM FORECAST SOUNDINGS ACROSS THE FOOTHILLS AND
PIEDMONT INDICATE THAT CAPE VALUES WILL EXCEED 2000 J/KG...EHI
BETWEEN.5 TO 1 M2/S2...SWEAT GREATER THAN 350. A WEAK BAND OF MAINLY
PRE FRONTAL SHRA MAY REACH THE NC MTNS DURING THE MORNING.
HOWEVER...AS THE LINE MOVE EAST ACROSS THE FOOTHILLS AND
PIEDMONT...CONDITIONS WILL BECOME MORE SUPPORTIVE FOR TSRA
ORGANIZATION INTO A QLCS. THE PRIMARY THREATS WITH THE QLCS WILL BE
DAMAGING STRAIGHT-LINE WINDS AND HAIL...ESPECIALLY ACROSS THE I-77
CORRIDOR. WE WILL CONTINUE TO HIGHLIGHT THE SVR WEATHER THREAT IN
THE HWO.
HIGH TEMPERATURE GUIDANCE ON THURSDAY REMAINS DIVIDED FROM THE VERY
WARM MAV...UPPER 90S...TO THE MET...LOWER TO MID 90S. GIVEN THE
PATTERN OF FALLING LOWER THE MID HEIGHTS...I WILL FAVOR THE MET.
FRIDAY...SHOULD VERIFY AS A FAIR WEATHER DAY AS CANADIAN HIGH
PRESSURE BUILD SOUTH ACROSS THE REGION IN THE WAKE OF THE COLD
FRONT. I WILL FORECAST DRY CONDITIONS WITH LIGHT NORTHEAST WINDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 115 PM TUESDAY...NO MAJOR CHANGES NEEDED TO THE GOING FCST.
THE MODELS AGREE WELL WITH A BUILDING RIDGE AND LARGE AREA OF DEEP
SUBSIDENCE CONTROLLING THE WX THROUGHOUT THE WEEKEND. AT THE SFC...A
CP HIGH WILL MOVE SOUTH OVER THE REGION SAT/SUN...AND ALONG WITH
RELATIVELY WARM MLVLS...DRY CONDS WITH NEAR SEASONAL TEMPS ARE
EXPECTED. THERE IS SOME DIFFERENCES WRT THE MAGNITUDE AND CHARACTER
OF THE NEXT S/W DEVELOPING OVER THE MIDWEST MON...HOWEVER WILL COUNT
ON A GENERAL INCREASE IN DYNAMICS ALOFT AND HIGHER LLVL MOISTURE
FLUX THROUGH NEW DAY 7. MODEL SOUNDINGS ARE SHOWING GOOD SBSAPE AND
ELCAPE POTENTIAL WITH SOME MODERATE BULK SHEAR...SO THE ENVIRONMENT
WILL BE SET FOR STRONG TO SEVERE CONVECTION DEVELOPING EACH
AFTERNOON MON THROUGH THE PERIOD. MAX TEMPS SHOULD BUMP A COUPLE
DEGREES EACH DAY ONCE SW/LY FLOW BECOMES MAINTAINED SUN NIGHT.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...VFR THROUGH THE FORECAST PERIOD...WITH A CAVEAT. EXPECT
ONLY HIGH CLOUDS WITH A NEARLY CALM WIND THROUGH DAYBREAK. NOT GOING
TO RULE OUT SOME BRIEF GROUND FOG AT DAYBREAK GIVEN THE RECENT
WETNESS. THROUGH THE DAY...THE FCST SOUNDINGS FROM MOST MODELS ARE
CAPPED...SO ONLY A FEW SCRAGGILY HIGH BASED STRATOCU ARE EXPECTED
THROUGH MOST OF THE AFTERNOON...UNDERNEATH SOME MID AND HIGH LEVEL
CONVECTIVE DEBRIS MOVING DOWN FROM THE NW. WIND SHOULD COME AROUND
TO WSW BECAUSE OF A LEE TROF DURING THE AFTERNOON. AND NOW HERE IS
THE CAVEAT...SOME OF THE CONVECTION ALLOWING MODELS SUGGEST A
COMPLEX OF THUNDERSTORMS WILL DEVELOP OVER SRN WV THIS AFTERNOON AND
THEN PLOW SOUTHWARD ACROSS THE PIEDMONT OF NC IN THE AFTERNOON...
PERHAPS WITH DECENT POTENTIAL FOR DAMAGING WIND GUSTS AND LARGE
HAIL. IN THAT CASE...THE CAP WOULD WORK TO THE ADVANTAGE OF THE
STORMS BY HOLDING THE LID ON THE DEEP CONVECTION AND STORING UP ALL
THE ENERGY UNTIL THE SQUALL LINE ARRIVES TO RELEASE IT. THIS IS ALL
CONJECTURE. THE FCST REFLECTS THE MOST LIKELY SCENARIO...WHICH IS
FOR NOTHING TO HAPPEN OTHER THAN ISOLATED EARLY EVENING STORMS.
HOWEVER...THE OTHER SCENARIO IS WITHIN THE REALM OF POSSIBILITIES SO
KEEP IT IN THE BACK OF YOUR MIND. EITHER WAY...THE EVENING SHOULD
BECOME UNEVENTFUL WITH LIGHT WIND AFTER SUNSET.
ELSEWHERE...EXPECT MAINLY INCREASING HIGH LEVEL CLOUDS FROM MCS
DEBRIS ARRIVING FROM THE NW THROUGH DAYBREAK. THERE COULD BE SOME
MVFR VISIBILITY IN THE VICINITY OF KAVL AROUND SUNRISE. FOR THIS
AFTERNOON...SCENARIO IS SIMILAR TO KCLT E OF THE BLUE RIDGE...WITH
ISOLATED THUNDERSTORMS POSSIBLE...BUT WILL NOT MENTION AT THIS TIME.
OUTLOOK...A COLD FRONT WILL BRING A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE REGION ON THURSDAY. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT AND PRODUCE GENERALLY QUIET WEATHER AND VFR
CONDITIONS THROUGH THE WEEKEND.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 94% HIGH 94% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...GOODMAN
NEAR TERM...HG/PAT
SHORT TERM...NED
LONG TERM...SBK
AVIATION...PM
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
919 PM CDT THU JUN 13 2013
.UPDATE...
ISSUED AT 919 PM CDT THU JUN 13 2013
MAIN CHANGE TO FORECAST INVOLVES PRECIPITATION CHANCES. FOR THIS
EVENING...DO EXPECT LIGHT SHOWERS/THUNDERSTORMS TO PERSIST IN NW
IA UNTIL ABOUT MID NIGHT. THIS IS ASSOCIATED WITH A WEAK 700 MB
FRONT.
FARTHER WEST...AM GOING TO DELAY CONVECTIVE CHANCES WEST OF I29
UNTIL AFTER 06Z AND REALLY NOT GO ABOVE A 20 PERCENT UNTIL AFTER
09Z. THE UPPER LEVEL WAVE IS WELL TO THE WEST YET AND AS A RESULT
THE STEEPER LAPSE RATES DO NOT ARRIVE INTO THE JAMES VALLEY UNTIL
06Z. OF EVEN GREATER CONCERN THE LOW LEVEL JET DOES NOT REALLY
INCREASE UNTIL AFTER 06Z. AS A RESULTS THE BEST THETA-E ADVECTION
IS NOT UNTIL ALMOST 12Z. BOTH RAP AND HRRR ARE MUCH SLOWER IN
DEVELOPING CONVECTION. IN FACT THE RAP HAS ALMOST NO CONVECTION
UNTIL AFTER 12Z. THAT MAY BE A LITTLE TOO SLOW GIVEN MUCAPES OF
1000 TO 1500 J/KG AND CIN NEAR ZERO AT KFSD BY 12Z AND APPROACHING
WEAK WAVE. CURRENT MENTION OF NICKEL TO HALF-DOLLAR SIZE HAIL IN
HWO FOR LATE TONIGHT AND TOMORROW SEEMS REASONABLE GIVEN AMOUNT OF
CAPE AVAILABLE TO STORMS...EVEN WITH EFFECTIVE SHEAR AROUND 20 KTS
FOR MORNING CONVECTION. TEMPERATURES LOOK ON TRACK FOR TONIGHT.
GRIDS UPDATED AND WILL UPDATE HWO SHORTLY TO SLOW DOWN TIMING OF
CONVECTION.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 405 PM CDT THU JUN 13 2013
ISOLATED SHOWERS AND THUNDERSTORMS THIS AFTERNOON WILL PASS OVER THE
AREA FROM SIOUX CITY TO STORM LAKE AND SOUTH WITH LITTLE FANFARE.
LATER TONIGHT IN AXIS OF INCREASING MOISTURE AND
INSTABILITY...ISOLATED STORMS ARE EXPECTED TO DEVELOP OVER MORE OF
THE AREA AND MOVE FROM WEST TO EAST...PROBABLY BECOMING SCATTERED BY
DAYBREAK IN THE EAST. AIR STILL DOES NOT LOOK UNSTABLE ENOUGH GIVEN
AVAILABLE MOISTURE AND MEAGER LIFT TO PRODUCE SEVERE WEATHER...BUT
SOME LATE COULD PUT DOWN SOME SMALL HAIL. THIS ACTIVITY WILL BE ONLY
SLOWLY INCREASING AS IT MOVES EAST INTO BETTER AREA OF THERMAL LIFT.
HOWEVER...INSTEAD OF DECREASING FRIDAY MORNING AS NOCTURNAL ACTIVITY
OFTEN DOES...EXPECT A CONTINUED SLOW INCREASE IN COVERAGE BECAUSE OF
INCREASING DYNAMIC SUPPORT AS WAVE AND SURFACE BOUNDARY APPROACH.
NIGHTTIME ACTIVITY HAS LITTLE SUPPORT FROM LOW LEVEL JET WHICH
DEVELOPS STRONGLY TO THE WEST OF OUR AREA...BUT EVEN THOUGH EXPECTED
TO DECREASE FRIDAY...IT WILL THEN BE MOVING INTO OUR AREA...SO
EXPECT SCATTERED ELEVATED STORMS TO CONTINUE DEVELOPING AT A TIME
WHEN THEY WOULD NORMALLY BE DECREASING. THE QUESTION REMAINS AT WHAT
TIME LATE IN THE DAY THE STORMS COULD BECOME MORE SURFACE BASED OR
WHETHER THEY EVEN WILL. HOWEVER...INSTABILITY SEEMS ENOUGH BY MIDDAY
FRIDAY FOR EVEN THESE ELEVATED STORMS TO PRODUCE ISOLATED SEVERE
HAIL REPORTS. TEMPERATURES TONIGHT AND FRIDAY WILL BE KEPT CLOSE TO
WHAT WE HAVE BEEN GOING FOR...A LITTLE COOLER THAN GUIDANCE IN THE
EAST DUE TO THE EXPECTED CLOUD COVER AND SCATTERED CONVECTION. WINDS
WILL INCREASE TO BREEZY LEVELS IN THE EAST FOR A WHILE FRIDAY AHEAD
OF SURFACE TROUGH/OCCLUDED FRONT.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 405 PM CDT THU JUN 13 2013
QUESTION FOR FRIDAY EVENING INTO THE OVERNIGHT IS WHETHER SURFACE
BASED CONVECTION FIRES ALONG THE APPROACHING FRONT...AND IF IT
DOES...WHEN AND WHERE. ELEVATED ACTIVITY ONGOING ACROSS OUR EAST
DURING THE AFTERNOON WILL LIKELY HINDER SURFACE HEATING SOMEWHAT.
ALSO A STRONG CAP IS FORECAST TO BE IN PLACE...ALTHOUGH THIS SHOULD
GRADUALLY BE ERODED AS COOLER MID LEVEL TEMPERATURES MOVE INTO THE
AREA. BEST UPPER FORCING WITH THE MAIN WAVE WILL STAY WELL TO OUR
NORTH. MEANWHILE BEST FRONTOGENETICAL FORCING LOOKS TO BE FOCUSED
ACROSS CENTRAL NEBRASKA. GIVEN THIS...COMBINED WITH UNCERTAINTY ON
HOW MUCH HEATING WE GET DURING THE DAY...SEEMS LIKE MOST LIKELY
SOLUTION HAS ONE AREA OF SHOWERS AND STORMS FORM NORTH OF OUR CWA
WITH THE BETTER UPPER LEVEL FORCING. AND ANOTHER AREA FORM IN SOUTH
CENTRAL NEBRASKA ALONG THE STRONGER PORTION OF THE
BOUNDARY...LEAVING OUR CWA IN THE MIDDLE. SUBTLE SIGNS THAT A
SECONDARY WAVE MAY EJECT OUT OF THE COLORADO ROCKIES DURING THE
AFTERNOON...WHICH MAY AID IN THE NEBRASKA DEVELOPMENT. EXPECT THIS
ACTIVITY TO THEN POTENTIALLY INCREASE NORTHEAST ALONG THE FRONT...AS
THE SECONDARY WAVE EJECTS EAST AND CAPPING WEAKENS DUE TO HEATING
AND COOLING ALOFT. QUESTION IS HOW FAR NORTH THIS CONVECTION GETS.
INDIVIDUAL STORM MOTION WILL TEND TO BE ALMOST DUE EASTERLY...THUS
THE BEST CHANCE WILL PROBABLY END UP ACROSS NORTHWEST IOWA AND
EXTREME SOUTHEAST SOUTH DAKOTA IN THE EVENING INTO THE OVERNIGHT.
STORMS WOULD INITIALLY BE SUPERCELLS BEFORE PROBABLY BECOMING MORE OF
A CLUSTER...WITH LARGE HAIL AND STRONG WINDS THE MAIN THREAT...BUT
GIVEN LOW LEVEL WIND FIELDS AN ISOLATED TORNADO WOULD ALSO BE
POSSIBLE IF STORMS GET INTO OUR AREA EARLY ENOUGH. FURTHER NORTH THE
THREAT SEEMS LOWER. HOWEVER WILL HAVE TO KEEP AN EYE ON THINGS...AS
IF AN ISOLATED STORM IS ABLE TO FORM ALONG THE FRONT NEAR THE JAMES
RIVER...IT WOULD LIKELY BECOME SUPERCELLUAR WITH CAPE AROUND 2000
J/KG AND DEEP LAYER SHEAR OF 40 OR MORE KTS.
SATURDAY SEES THE FRONT LIKELY TO OUR SOUTH. BUT DECENT UPPER
SUPPORT IN THE RIGHT ENTRANCE OF A STRONG UPPER JET IS EXPECTED.
MODELS ALSO SUGGEST THAT LOW TO MODERATE INSTABILITY MAY LINGER
ALONG AND SOUTH OF INTERSTATE 90. THUS WHILE IT WOULD SEEM LIKELY
THAT THE GREATEST THUNDERSTORM COVERAGE WILL REMAIN SOUTH IN THE
VICINITY OF THE FRONT...CAN NOT RULE OT ISOLATED TO SCATTERED
ACTIVITY SOUTH OF INTERSTATE 90. AGAIN SHEAR PROFILES WOULD SUPPORT A
LARGE HAIL AND WIND THREAT WITH ANY STORM THAT DOES FORM. HIGHS
DEPENDENT ON CLOUD COVER AND COVERAGE OF SHOWERS AND STORMS...BUT
NEAR SEASONABLE READINGS IN THE UPPER 70S TO LOW 80S SEEM PROBABLE.
ON SUNDAY A STRONGER WAVE WILL EJECT SOUTHEAST OUT OF CANADA AND
INTO THE FAR NORTHERN PLAINS. STILL UNCERTAINTY ON AVAILABLE
MOISTURE AND WHERE THE BEST FORCING ENDS UP. WIND FIELDS WOULD
SUGGEST A SEVERE THREAT WITH ANY STORMS THAT COULD FORM...BUT AGAIN
LATEST INDICATIONS ARE THAT THE BEST THREAT MAY END UP SOUTH OF US.
BUT SOMETHING TO KEEP AN EYE ON. HIGHS PROBABLY A COUPLE DEGREES
WARMER ON SUNDAY...BUT STILL AROUND OR JUST SLIGHTLY ABOVE AVERAGE.
DRIER AND COOLER AIR MOVES IN ON MONDAY BEHIND THE WAVE. MODELS
COMING IN A BIT COOLER ALOFT...AND THUS HIGHS LOOK LIKE THEY WILL
END UP AT LEAST A FEW DEGREES BELOW SEASONABLE NORMALS...WITH MID TO
UPPER 70S EXPECTED. RIDGING THEN BEGINS TO BUILD IN TUESDAY INTO
THURSDAY. ALTHOUGH LATEST RUNS SLOW THIS DOWN A BIT...SUGGESTING
SLIGHTLY COOLER HIGHS POSSIBLE. EITHER WAY EXPECTING READINGS
AROUND AVERAGE THROUGH THURSDAY...WITH A SLOW WARMING TREND EACH
DAY. RIDGE AXIS SHOULD MOVE OVERHEAD AROUND WEDNESDAY. UNCERTAINTY
ON TIMING AND PLACEMENT OF SUBTLE WAVES RIDING OVER THE RIDGE...BUT
THE SETUP WOULD SUGGEST AT LEAST THE MENTION OF A RETURN OF ISOLATED
SHOWERS AND THUNDERSTORMS ANYTIME LATER WEDNESDAY INTO THURSDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 633 PM CDT THU JUN 13 2013
THUNDERSTORMS IN THE VICINITY OF KSUX AT 23Z WILL BE MOVING
SOUTHEAST OF THERE BY 01-02Z. OTHERWISE VFR CONDITIONS THROUGH EARLY
FRIDAY MORNING. EXPECT SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
SOUTH OF INTERSTATE 90 FROM AROUND 09Z-15Z...AND THEN ANOTHER ROUND
OF THUNDERSTORMS TO DEVELOP FRIDAY AFTERNOON...BUT THESE WILL BE
MAINLY EAST OF INTERSTATE 29.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...SCHUMACHER
SHORT TERM...
LONG TERM...CHENARD
AVIATION...MG
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1007 AM MDT WED JUN 12 2013
.UPDATE...
ISSUED AT 947 AM MDT WED JUN 12 2013
BROAD AREA OF CLOUD COVER REMAINS OVER WESTERN SOUTH DAKOTA
SPREADING INTO NORTHEAST WYOMING ON BACK-SIDE OF DEPARTING LOW.
MODELS CONTINUE TO BE RELUCTANT IN DISSIPATING CLOUD COVER UNTIL
LATER THIS AFTERNOON. MORNING UPDATE HAD ADDRESSED THIS...ALONG
WITH TAPERING BACK HIGH TEMPS OVER THE PLAINS. HAVE ALSO DELAYED
CONVECTION CHANCES OVER NERN WY/BLKHLS AS INSTABILITY WILL REMAIN
WEAK UNTIL LATER IN THE DAY. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 308 AM MDT WED JUN 12 2013
WATER VAPOR IMAGERY SHOWS A CUT OFF LOW ACROSS THE PACIFIC
NORTHWEST...AND WEAK RIDGING ACROSS THE NORTHERN HIGH PLAINS IN
THE WAKE OF THE SHORTWAVE NOW CROSSING EAST RIVER SD INTO
MINNESOTA. SURFACE ANALYSIS SHOWS HIGH PRESSURE FROM MONTANA TO
COLORADO.
HIGH PRESSURE WILL SLIDE INTO CENTRAL SOUTH DAKOTA TODAY BRINGING
QUIET WEATHER TO THE AREA FOR MUCH OF THE DAY TODAY. RETURN FLOW
WILL SET BACK UP FROM EASTERN MONTANA INTO NORTHEAST WYOMING AND
WESTERN SOUTH DAKOTA. TEMPERATURES IN THE 70S TO LOWER 80S ARE AGAIN
EXPECTED. UNSTABLE AIRMASS WILL REDEVELOP THIS AFTERNOON WITH MLCAPE
RANGING FROM 800 TO 1500 J/KG...AND WITH WEAKER CAPPING THAN
YESTERDAY. LOW LEVEL SHEAR WILL RAMP UP THROUGH THE LATE AFTERNOON
AND EVENING AS THE RETURN FLOW/LLJ STRENGTHENS. ISOLATED STORMS MAY
INITIATE OVER THE BLACK HILLS THIS AFTERNOON. OTHERWISE A SERIES OF
WAVES PUSHING INTO WESTERN WYOMING AND MONTANA WILL BRING
THUNDERSTORMS TOWARD THE BIG HORNS INTO CENTRAL MONTANA LATE THIS
AFTERNOON INTO TONIGHT. A DRYLINE WILL SET UP SOMEWHERE ACROSS
CENTRAL TO NORTHEASTERN WYOMING...AND THIS COULD BE THE FOCUS FOR
MORE CONVECTION. SUFFICIENT SHEAR WILL SUPPORT SUPERCELL DEVELOPMENT
LARGE HAIL AND DAMAGING WINDS POSSIBLE. THE BULK OF CONVECTION WILL
END BY 06Z...HOWEVER SOME LINGERING STORMS WILL BE POSSIBLE
OVERNIGHT WITHIN THE BAND OF THETA E ADVECTION AND LOW LEVEL JET
ACROSS WESTERN SOUTH DAKOTA.
STRENGTHENING ACTIVE SOUTHWEST FLOW ALOFT IS EXPECTED THURSDAY WITH
THE APPROACH OF THE NEXT TROUGH. SURFACE LOW WILL ALSO STRENGTHEN
NEAR THE MONTANA TO WYOMING BORDER LATE IN THE DAY ALONG A
BAROCLINIC ZONE. STRONG THETA E ADVECTION WILL CONTINUE ACROSS THE
CWA AHEAD OF THE SURFACE LOW. MOST LOCATIONS WILL SEE TEMPERATURES
REACH THE 80S AND DEWPOINTS REACHING THE UPPER 50S TO LOWER 60S. THE
SURFACE LOW WILL PUSH ACROSS EASTERN MONTANA THURSDAY AFTERNOON...AND
INTO THE DAKOTAS THURSDAY NIGHT. A SERIES OF UPPER WAVES WILL
COMBINE WITH A COLD FRONT CROSSING THE AREA TO BRING ANOTHER ROUND
OF THUNDERSTORMS. LOW LEVEL JET WILL CONTINUE ACROSS WESTERN SOUTH
DAKOTA...WHICH WILL AGAIN RESULT IN ENOUGH SHEAR FOR SUPERCELL
DEVELOPMENT. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN THREATS
THURSDAY. CONVECTION WILL PUSH NORTHEASTWARD OVERNIGHT...CLEARING
THE CWA LATE THURSDAY NIGHT.
&&
.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 308 AM MDT WED JUN 12 2013
MEAN WESTERN CONUS TROUGHING WILL CONTINUE IN THE
PERIOD...WITH TEMPORARY WESTERN TROUGH REMOVAL FRI-SUN PER TROUGH
KICKING BY AN ADVANCING NORTHERN PAC UPPER TROUGH. RETAINED LOW CHANCES
FOR POPS FRI OVER NE WY AND FAR SE FA GIVEN WITH THE ADVECTION OF
THE MAIN UPPER TROUGH INTO SOUTHERN CANADA. THIS UPPER TROUGH WILL
FRACTURE OVER SOUTHERN MB/SK WITH THE REMAINING VORT LOBE SHIFTING
SE SUN. MEAN RIDGING FAVORED EARLY NEXT WEEK AHEAD OF RE-INITIATED
WESTERN CONUS TROUGHING...SUPPORTING A WARMING TREND WITH INCREASING
CHANCES FOR SHRA/TS AS WEAK DISTURBANCES ADVECT EAST OUT OF THE MEAN
WESTERN CONUS TROUGH. BEST CHANCES FOR ANY PRECIP LOOKS TO REMAIN
OVER NE WY AND SOUTHERN PORTIONS OF THE FA...GIVEN HIGH TERRAIN
INITIATION AND LL THETA-E RIDGING. KEPT POPS FAIRLY LOW GIVEN
CONCERNS ON IMPULSE STRENGTH/TRACK/AND LL MOISTURE RECOVERY.
NOT MUCH CHANGES TO PREVIOUS POP NUMBERS...RETAINING LOW NUMBERS
IN MOST PERIODS. MONDAY COULD END UP DRY MOST PLACES...ESP IF
RIDGING IS DELAYED. OTHERWISE...A TRANSITION TO SW FLOW EARLY NEXT
WEEK SUPPORTS A SMALL UPTICK IN POPS. GENERALLY NORMAL TEMPS
EXPECTED IN THE PERIOD. DEGREE OF CAA BEHIND SUNDAY/S WAVE STILL
WAVERING IN GFS/ECMWF SOLUTIONS WITH POTENTIALLY COOLER NUMBERS
POSSIBLE. HAVE SIDED SLIGHTLY BELOW NORMAL FOR MONDAY ATTM.
OTHERWISE...WARMING TREND LIKELY BEYOND MONDAY GIVEN EASTERN
TRANSLATION OF THE NEXT RIDGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 509 AM MDT WED JUN 12 2013
IFR/LIFR CIGS WILL BE FOUND FROM NE WY NEAR W43...SE TO RAP AND IN
SURROUNDING AREAS NEAR THE BH. FLOW WILL VEER EASTERLY WHICH MAY
ALLOW CIGS TO PERSIST INTO EARLY AFTERNOON ALONG THE EASTERN BH
FOOTHILLS INCLUDING RAP. OTHERWISE...VFR CONDITIONS ARE EXPECTED
ACROSS THE REMAINDER OF THE REGION AS WEAK SFC HIGH PRESSURE
SHIFTS SOUTHEAST ACROSS THE CENTRAL DAKOTAS. ANOTHER MID LEVEL
IMPULSE IN SW FLOW MAY SUPPORT AN ISOLD TS LATE THIS AFTERNOON AND
OVERNIGHT FROM NE WY INTO NW SD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...77
SHORT TERM...13
LONG TERM...JC
AVIATION...JC
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
514 AM MDT WED JUN 12 2013
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 308 AM MDT WED JUN 12 2013
WATER VAPOR IMAGERY SHOWS A CUT OFF LOW ACROSS THE PACIFIC
NORTHWEST...AND WEAK RIDGING ACROSS THE NORTHERN HIGH PLAINS IN
THE WAKE OF THE SHORTWAVE NOW CROSSING EAST RIVER SD INTO
MINNESOTA. SURFACE ANALYSIS SHOWS HIGH PRESSURE FROM MONTANA TO
COLORADO.
HIGH PRESSURE WILL SLIDE INTO CENTRAL SOUTH DAKOTA TODAY BRINGING
QUIET WEATHER TO THE AREA FOR MUCH OF THE DAY TODAY. RETURN FLOW
WILL SET BACK UP FROM EASTERN MONTANA INTO NORTHEAST WYOMING AND
WESTERN SOUTH DAKOTA. TEMPERATURES IN THE 70S TO LOWER 80S ARE AGAIN
EXPECTED. UNSTABLE AIRMASS WILL REDEVELOP THIS AFTERNOON WITH MLCAPE
RANGING FROM 800 TO 1500 J/KG...AND WITH WEAKER CAPPING THAN
YESTERDAY. LOW LEVEL SHEAR WILL RAMP UP THROUGH THE LATE AFTERNOON
AND EVENING AS THE RETURN FLOW/LLJ STRENGTHENS. ISOLATED STORMS MAY
INITIATE OVER THE BLACK HILLS THIS AFTERNOON. OTHERWISE A SERIES OF
WAVES PUSHING INTO WESTERN WYOMING AND MONTANA WILL BRING
THUNDERSTORMS TOWARD THE BIG HORNS INTO CENTRAL MONTANA LATE THIS
AFTERNOON INTO TONIGHT. A DRYLINE WILL SET UP SOMEWHERE ACROSS
CENTRAL TO NORTHEASTERN WYOMING...AND THIS COULD BE THE FOCUS FOR
MORE CONVECTION. SUFFICIENT SHEAR WILL SUPPORT SUPERCELL DEVELOPMENT
LARGE HAIL AND DAMAGING WINDS POSSIBLE. THE BULK OF CONVECTION WILL
END BY 06Z...HOWEVER SOME LINGERING STORMS WILL BE POSSIBLE
OVERNIGHT WITHIN THE BAND OF THETA E ADVECTION AND LOW LEVEL JET
ACROSS WESTERN SOUTH DAKOTA.
STRENGTHENING ACTIVE SOUTHWEST FLOW ALOFT IS EXPECTED THURSDAY WITH
THE APPROACH OF THE NEXT TROUGH. SURFACE LOW WILL ALSO STRENGTHEN
NEAR THE MONTANA TO WYOMING BORDER LATE IN THE DAY ALONG A
BAROCLINIC ZONE. STRONG THETA E ADVECTION WILL CONTINUE ACROSS THE
CWA AHEAD OF THE SURFACE LOW. MOST LOCATIONS WILL SEE TEMPERATURES
REACH THE 80S AND DEWPOINTS REACHING THE UPPER 50S TO LOWER 60S. THE
SURFACE LOW WILL PUSH ACROSS EASTERN MONTANA THURSDAY AFTERNOON...AND
INTO THE DAKOTAS THURSDAY NIGHT. A SERIES OF UPPER WAVES WILL
COMBINE WITH A COLD FRONT CROSSING THE AREA TO BRING ANOTHER ROUND
OF THUNDERSTORMS. LOW LEVEL JET WILL CONTINUE ACROSS WESTERN SOUTH
DAKOTA...WHICH WILL AGAIN RESULT IN ENOUGH SHEAR FOR SUPERCELL
DEVELOPMENT. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN THREATS
THURSDAY. CONVECTION WILL PUSH NORTHEASTWARD OVERNIGHT...CLEARING
THE CWA LATE THURSDAY NIGHT.
&&
.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 308 AM MDT WED JUN 12 2013
MEAN WESTERN CONUS TROUGHING WILL CONTINUE IN THE
PERIOD...WITH TEMPORARY WESTERN TROUGH REMOVAL FRI-SUN PER TROUGH
KICKING BY AN ADVANCING NORTHERN PAC UPPER TROUGH. RETAINED LOW CHANCES
FOR POPS FRI OVER NE WY AND FAR SE FA GIVEN WITH THE ADVECTION OF
THE MAIN UPPER TROUGH INTO SOUTHERN CANADA. THIS UPPER TROUGH WILL
FRACTURE OVER SOUTHERN MB/SK WITH THE REMAINING VORT LOBE SHIFTING
SE SUN. MEAN RIDGING FAVORED EARLY NEXT WEEK AHEAD OF RE-INITIATED
WESTERN CONUS TROUGHING...SUPPORTING A WARMING TREND WITH INCREASING
CHANCES FOR SHRA/TS AS WEAK DISTURBANCES ADVECT EAST OUT OF THE MEAN
WESTERN CONUS TROUGH. BEST CHANCES FOR ANY PRECIP LOOKS TO REMAIN
OVER NE WY AND SOUTHERN PORTIONS OF THE FA...GIVEN HIGH TERRAIN
INITIATION AND LL THETA-E RIDGING. KEPT POPS FAIRLY LOW GIVEN
CONCERNS ON IMPULSE STRENGTH/TRACK/AND LL MOISTURE RECOVERY.
NOT MUCH CHANGES TO PREVIOUS POP NUMBERS...RETAINING LOW NUMBERS
IN MOST PERIODS. MONDAY COULD END UP DRY MOST PLACES...ESP IF
RIDGING IS DELAYED. OTHERWISE...A TRANSITION TO SW FLOW EARLY NEXT
WEEK SUPPORTS A SMALL UPTICK IN POPS. GENERALLY NORMAL TEMPS
EXPECTED IN THE PERIOD. DEGREE OF CAA BEHIND SUNDAY/S WAVE STILL
WAVERING IN GFS/ECMWF SOLUTIONS WITH POTENTIALLY COOLER NUMBERS
POSSIBLE. HAVE SIDED SLIGHTLY BELOW NORMAL FOR MONDAY ATTM.
OTHERWISE...WARMING TREND LIKELY BEYOND MONDAY GIVEN EASTERN
TRANSLATION OF THE NEXT RIDGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 509 AM MDT WED JUN 12 2013
IFR/LIFR CIGS WILL BE FOUND FROM NE WY NEAR W43...SE TO RAP AND IN
SURROUNDING AREAS NEAR THE BH. FLOW WILL VEER EASTERLY WHICH MAY
ALLOW CIGS TO PERSIST INTO EARLY AFTERNOON ALONG THE EASTERN BH
FOOTHILLS INCLUDING RAP. OTHERWISE...VFR CONDITIONS ARE EXPECTED
ACROSS THE REMAINDER OF THE REGION AS WEAK SFC HIGH PRESSURE
SHIFTS SOUTHEAST ACROSS THE CENTRAL DAKOTAS. ANOTHER MID LEVEL
IMPULSE IN SW FLOW MAY SUPPORT AN ISOLD TS LATE THIS AFTERNOON AND
OVERNIGHT FROM NE WY INTO NW SD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...13
LONG TERM...JC
AVIATION...JC
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1224 AM CDT WED JUN 12 2013
.UPDATE...
AVIATION DISCUSSION HAS BEEN UPDATED FOR 06Z TAFS.
A LOT OF LOW LEVEL DRY AIR HAS FILTERED INTO THE CWA THIS EVENING
AS SURFACE DEW POINTS HAVE DROPPED AT ALL LOCATIONS. STRONG
CAPPING ALONG WITH 1000 TO 1500 J/KG OR MORE OF MUCAPE EXISTS ACROSS
THE CWA THIS EVENING. WITH THE LARGE SCALE ASCENT AND WAA WITH THE
APPROACHING SHORT WAVE TROUGH...THUNDERSTORMS WERE DEVELOPING AND
INCREASING IN COVERAGE ACROSS EASTERN WY INTO NORTHWEST NEBRASKA
THIS EVENING. EXPECT THIS TREND TO CONTINUE OVER THE NEXT SEVERAL
HOURS AS EVERYTHING HEADS OFF TO THE NORTHEAST. EXPECT CONVECTION
TO STILL LINE OUT AS IT MOVES EAST ACROSS SOUTHERN SD TONIGHT AND
MAY BE SEVERE AS 0-3KM SHEAR REMAINS STRONG. WINDS WILL BE THE
MAIN THREAT. AREAS ALONG AND SOUTH OF I-90 HAVE THE BEST CHANCE OF
SEVERE. THE LATEST HRRR RUN WAS SHOWING MORE NUMEROUS SHOWERS AND
STORMS DEVELOPING OVER THE REGION THROUGH THE NIGHT WITH NOT MUCH
OF A LINE ACROSS THE SOUTH. WILL HAVE TO WAIT AND SEE. ALREADY
HAVE IN GOOD CHANCES OF RAINFALL ACROSS MUCH OF THE CWA TONIGHT.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT
THE CHANCE FOR SEVERE WEATHER TONIGHT IS THE MAIN FORECAST
CHALLENGE. AN UPPER LEVEL SHORTWAVE WILL RIDE OVER THE TOP OF A
RIDGE CURRENTLY OVER THE PLAINS AND ACROSS THE STATE TONIGHT INTO
WEDNESDAY. A SURFACE LOW PRESSURE SYSTEM WILL TRACK ACROSS
NEBRASKA TONIGHT...WITH MOISTURE WRAPPING AROUND IT TO THE NORTH
ACROSS SOUTH DAKOTA. THE BEST INSTABILITY LOOKS TO BE OVER THE
SOUTHERN PART OF THE STATE AND ACROSS NEBRASKA. 0-6 KM BULK SHEAR
VALUES IN EXCESS OF 50 KTS DEVELOP ACROSS SOUTHERN SOUTH DAKOTA AS
WELL. LOOKING AS THOUGH STORMS WILL DEVELOP ACROSS EASTERN WYOMING
AND WESTERN SOUTH DAKOTA DURING THE EVENING HOURS...THEN TRACK
EASTWARD THROUGH THE NIGHT AND INTO EARLY WEDNESDAY. AGAIN...THE
MAIN FOCUS FOR SEVERE WEATHER WILL BE ACROSS THE SOUTHERN HALF OF
THE STATE WHERE THE SET UP WILL BE BETTER FOR HAIL AND STRONG
WINDS. MAY SEE A BOWING FEATURE AFFECT PARTS OF THE FAR SOUTHERN
CWA...MAINLY SOUTH OF INTERSTATE 90 IN THE 03Z-09Z TIME FRAME.
AFTER SOME LINGERING PRECIPITATION WEDNESDAY MORNING...HIGH
PRESSURE DROPS OVER THE REGION AND LOOKS TO KEEP THINGS DRY
THROUGH THE DAY THURSDAY. SOME DISAGREEMENT IN THE MODELS WITH
THURSDAY NIGHT AS THE GFS AND THE NAM INDICATE PRECIPITATION
DEVELOPING AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM...WHILE THE
ECMWF KEEPS THINGS DRY. WILL GO AHEAD AND KEEP A SMALL POP TO
ACCOUNT FOR THE DIFFERENCES.
NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES WILL CONTINUE DURING
THE SHORT TERM...WITH HIGHS MAINLY IN THE MID TO UPPER 70S BOTH
WEDNESDAY AND THURSDAY.
.LONG TERM...FRIDAY THROUGH TUESDAY
THE PERIOD STARTS WITH UPPER LEVEL RIDGING OVERHEAD AND A TROUGH
WORKING ITS WAY INTO THE NORTHERN ROCKIES. THE ASSOCIATED SURFACE
LOW WILL ALSO MOVE INTO THE PLAINS STATES FRIDAY...AND THERE SHOULD
BE SOME MOISTURE RETURN...WITH MODEL BOUNDARY LAYER DEWPOINTS
RISING BACK INTO THE UPPER 50S TO LOW 60S. MODELS ARE NOT SHOWING
ANY REAL SIGNIFICANT WAVES OF ENERGY KICKING OUT AHEAD OF THE
TROUGH AND RIDING OVER THE RIDGE ON FRIDAY...AND THE MOST
SIGNIFICANT 500 MB HEIGHT FALLS DO NOT OCCUR UNTIL LATE FRIDAY
INTO SATURDAY. SO AT THIS TIME IT LOOKS LIKE THE BEST
PRECIPITATION CHANCES WILL OCCUR WITH THE COLD FRONTAL PASSAGE
EARLY SATURDAY MORNING. A PROGRESSIVE PATTERN REMAINS IN PLACE
THROUGH THE REMAINDER OF THE PERIOD...WITH SEVERAL SHORTWAVES
MOVING THROUGH NORTHWEST FLOW. OF COURSE...TIMING AND INTENSITY OF
THESE WAVES DIFFERS BETWEEN MODELS...SO DID NOT MODIFY THE
ALLBLEND SOLUTIONS THROUGH THE END OF THE LONG TERM PERIOD.
OVERALL TEMPERATURES APPEAR TO BE RIGHT AROUND...TO EVEN SLIGHTLY
ABOVE NORMAL THROUGH THE LONG TERM PERIOD.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
AN UPPER LEVEL LOW PRESSURE TROUGH WILL TRAVERSE OVER THE REGION
TONIGHT AND EARLY WEDNESDAY BRINGING SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS. WITH GOOD COVERAGE EXPECTED...INSERTED
SHOWERS AND VICINITY THUNDER AT ALL TERMINALS. THIS WAVE OF
PRECIPITATION WILL MOVE BY ON WEDNESDAY MORNING. EXPECT CEILINGS
TO BE VFR THROUGH THE ENTIRE TAF PERIOD WITH MAYBE SOME REDUCTION
IN VISIBILITY WITH ANY RAINFALL. WILL WATCH FOR ANY THUNDER
EXPECTED AT ANY STATION. SURFACE HIGH PRESSURE WILL BUILD IN
WEDNESDAY AFTERNOON AND EVENING. SKIES WILL CLEAR WEDNESDAY
EVENING WITH WINDS BECOMING LIGHT.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...PARKIN
LONG TERM...SERR
AVIATION...TDK
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
1024 PM CDT THU JUN 13 2013
.UPDATE...
ADJUSTED POPS AND TEMPERATURES FOR THE REMAINDER OF THE NIGHT.
&&
.DISCUSSION...
CONVECTION HAS ALL BUT ENDED ACROSS THE AREA WITH ONLY SOME LIGHT
SHOWERS REMAINING ACROSS CROCKETT COUNTY. UPPER LOW CURRENTLY NEAR
THE BIG BEND WILL LIFT SLOWLY NORTH ACROSS THE TRANS PECOS REGION
THROUGH FRIDAY MORNING. LATEST NAM AND HRRR SHOW SOME ADDITIONAL
CONVECTION LIFTING NORTH ACROSS SOUTHWEST COUNTIES TOWARDS
DAYBREAK SO WILL KEEP INHERITED SLIGHT CHANCE TO LOW END CHANCE
POPS GOING ROUGHLY SOUTH AND WEST OF A SAN ANGELO TO JUNCTION LINE
FOR THE REMAINDER OF THE NIGHT. OVERNIGHT LOW TEMPERATURES WERE
ALSO RAISED A FEW DEGREES BASED ON TRENDS AND EXPECTED CLOUD
COVER.
&&
.PREV DISCUSSION... /ISSUED 655 PM CDT THU JUN 13 2013/
DISCUSSION...
SEE AVIATION SECTION.
AVIATION...
SCATTERED SHOWERS AND THUNDERSTORMS OVER CENTRAL AND SOUTHERN PARTS
OF WEST CENTRAL TEXAS ARE MOVING TO THE NORTHWEST...AND WILL POTENTIALLY
AFFECT THE KSJT AND KBBD TAF SITES DURING THE FIRST HOUR IN THE TAF
PERIOD /00-01Z/. GUSTY WINDS 35-40 KT ARE POSSIBLE IN AND NEAR THE
STORMS...AND A FEW OF THE STORMS WILL LIKELY CONTAIN FREQUENT
LIGHTNING. BRIEF REDUCTIONS IN CLOUD CEILING AND VISIBILITY ARE
POSSIBLE IN THE LOCALLY HEAVY RAIN WHICH ACCOMPANIES THIS
CONVECTION. THE SHOWERS AND STORMS WILL GRADUALLY DISSIPATE LATE
THIS EVENING. CLOUD COVER WILL DECREASE DURING THE NIGHT WITH VFR
CONDITIONS EXPECTED TO PREVAIL. LATE NIGHT INCREASE IN BOUNDARY
LAYER MOISTURE LOOKS MARGINAL FOR LOW CLOUD DEVELOPMENT ACROSS OUR
SOUTHERN COUNTIES. HOLDING OFF WITH A LOW CLOUD MENTION FOR NOW
AND WILL REVISIT THIS WITH THE NEXT /06Z/ TAF PACKAGE. A VFR-BASED
CUMULUS FIELD IS EXPECTED TO DEVELOP DURING THE DAY THURSDAY.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP PRIMARILY
DURING THE AFTERNOON... WITH THE BETTER COVERAGE ANTICIPATED
ACROSS ROUGHLY WEST OF A SWEETWATER TO SAN ANGELO TO SONORA LINE.
SOME OF THE SHOWERS MAY DEVELOP BY MID-TO-LATE MORNING THURSDAY
ACROSS THE SOUTHWESTERN PART OF WEST CENTRAL TEXAS /SOUTHWEST OF A
MERTZON TO SONORA LINE/. AT THIS TIME...CARRYING VCSH FOR ALL AREA
TAF SITES EXCEPT KABI FOR THURSDAY AFTERNOON. MAY ADJUST THE
TIMING WITH THE NEXT TAF PACKAGE. SIMILAR TO TODAY...WILL HAVE A
POSSIBILITY OF GUSTY WINDS...FREQUENT LIGHTNING...AND BRIEF CLOUD
CEILING AND VISIBILITY REDUCTIONS IN THE LOCALLY HEAVY RAINFALL
WHICH ACCOMPANIES SOME OF THE STORMS.
19
PREV DISCUSSION... /ISSUED 605 PM CDT THU JUN 13 2013/
UPDATE...
WIDLEY SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH
MID EVENING SOUTH OF THE BIG COUNTRY. POPS WERE ADDED ACROSS
EASTERN PORTIONS OF THE CONCHO VALLEY...HEARTLAND AND NORTHWEST
HILL COUNTRY THROUGH MID EVENING. SEVERE WEATHER IS NOT EXPECTED
BUT STORMS WILL BE CAPABLE OF BRIEF HEAVY RAINFALL...WIND GUSTS TO
45 MPH AND DANGEROUS CLOUD TO GROUND LIGHTNING. NO OTHER CHANGES
MADE AT THIS TIME.
PREV DISCUSSION... /ISSUED 331 PM CDT THU JUN 13 2013/
SHORT TERM...
/TONIGHT THROUGH FRIDAY/
AN UPPER LOW IS SITUATED OVER THE BIG BEND REGION EARLY THIS
AFTERNOON AT THE BASE OF AN UPPER RIDGE THAT EXTENDS NORTH THROUGH
THE PLAINS STATES. PER LATEST RADAR...A LARGE AREA OF ASSOCIATED
SHOWERS AND THUNDERSTORMS EXTENDS FROM THE BIG BEND COUNTRY EAST
TO THE TEXAS GULF COAST. THIS AREA OF SHOWERS IS SLOWLY MAKING ITS
WAY NORTH AND SHOULD ENTER OUR SOUTHERN TIER OF COUNTIES LATER
THIS AFTERNOON. THE CENTER OF THE UPPER LOW IS FORECAST TO MOVE
NORTH ON A TRACK JUST WEST OF THE FORECAST AREA TO A POSITION OVER
THE NORTHERN PANHANDLE BY LATE TOMORROW. THE BULK OF SHOWERS
ASSOCIATED WITH THIS SYSTEM WILL REMAIN WEST OF THE CWA WITH THE
BEST CHANCE OF RAINFALL FOR OUR AREA BEING THE SOUTHWESTERN CWA
THROUGH TONIGHT AND THROUGH THE DAY TOMORROW...WITH POPS
DECREASING FROM SOUTHWEST TO NORTHEAST. AFTERNOON HIGHS TOMORROW
WILL REFLECT THE EXPECTED CLOUD COVER AND RAINFALL WITH MID 80S
OVER THE SOUTHWESTERN CWA TO THE MID 90S OVER THE NORTHEASTERN
CWA...WHICH SHOULD BE RAIN FREE WITH LESS CLOUD COVER. LOOKING FOR
MORNING LOWS TOMORROW IN THE LOWER 70S ACROSS ALL OF THE FORECAST
AREA.
LONG TERM...
/FRIDAY NIGHT THROUGH THURSDAY/
AN UPPER LEVEL LOW CONTINUES TO SPIN IN NORTH CENTRAL MEXICO
TODAY. THIS WILL MOVE NORTH INTO WEST TEXAS THROUGH
SATURDAY...BEFORE MOVING OFF TO THE NORTHEAST SATURDAY NIGHT. HAVE
KEPT IN SLIGHT CHANCE TO CHANCE POPS FOR THE AREA FRIDAY NIGHT
THROUGH SATURDAY. HAVE KEPT HIGHER POPS TO THE WEST AS THE ECMWF
CONTINUES TO BE THE LONE MODEL WITH THE HIGHEST PROBABILITY OF
PRECIPITATION ACROSS THE CENTRAL PART OF THE FORECAST AREA. WITH
PRECIPITABLE WATERS INCREASING TO NEAR 1.75 INCHES...AND THE SLOW
MOVING NATURE OF THE STORMS...WE MAY SEE SOME LOCALLY HEAVY
RAINFALL AND MINOR FLOODING UNDER THE STRONGER STORMS. IN
ADDITION...DANGEROUS CLOUD TO GROUND LIGHTNING AND GUSTY WINDS
WILL BE POSSIBLE...BUT WIDESPREAD SEVERE WEATHER IS NOT EXPECTED.
FOLLOWING OUR RAIN CHANCES THROUGH SATURDAY...A WEAK RIDGING TO
ZONAL PATTERN IS EXPECTED TO SET UP ACROSS THE SOUTHWEST U.S. THIS
WILL BRING WARMER WEATHER BACK INTO THE AREA THROUGH THE REST OF
THE FORECAST. HOWEVER...HEIGHTS/THICKNESSES ARE NOT EXPECTED TO
REACH THE SAME LEVELS AS WERE EXPERIENCED EARLIER THIS WEEK...SO
HIGHS SHOULD STAY BELOW TRIPLE DIGIT VALUES FOR THE MOST PART.
HAVE GONE AHEAD AND INTRODUCED SOME SLIGHT CHANCE POPS FOR
NORTHERN AREAS MONDAY NIGHT INTO TUESDAY OF NEXT WEEK. MEDIUM
RANGE GUIDANCE AGREES THAT A COLD FRONT WILL MOVE SOUTH INTO THE
RED RIVER VALLEY OR JUST SOUTH OF THERE BY EARLY NEXT WEEK AS A
RESULT OF A SFC HIGH PRESSURE BUILDING ACROSS THE CENTRAL/SOUTHERN
PLAINS BEHIND AN UPPER LEVEL LOW MOVING THROUGH THE GREAT LAKES.
THE ECMWF AND CANADIAN MODELS CARRY PRECIPITATION FARTHER SOUTH
INTO THE CONCHO VALLEY AND HEARTLAND...BUT WILL HOLD POPS NORTH OF
THE INTERSTATE 20 CORRIDOR FOR NOW AS FLOW ALOFT IS EXPECTED TO BE
FAIRLY WEAK AND WESTERLY IN OUR AREA...AND JUST HOW FAR SOUTH THE
FRONT WILL MAKE IT IS QUESTIONABLE THIS TIME OF THE YEAR.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 95 73 90 71 92 / 5 5 10 20 30
SAN ANGELO 94 72 89 71 93 / 20 30 30 30 30
JUNCTION 91 72 86 71 92 / 30 20 30 20 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
241 PM CDT WED JUN 12 2013
.SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)...MODELS STILL SHOW
LOTS OF AVAILABLE MOISTURE THROUGH THURSDAY NIGHT (PWATS AROUND 2
INCHES)...ALTHOUGH THE IMPACTS FROM THE UPPER LOW BEGIN TO SHIFT
TO THE NORTHWEST AND OUT OF THE CWFA. AS A RESULT...POP FORECAST
WILL REFLECT HIGHER POPS OUT TO THE WEST FOR THE AFTERNOON AND
EVENING PERIODS THROUGH THURSDAY NIGHT. POP GUIDANCE FROM MODELS
(ESPECIALLY ECMWF) LIKELY A BIT TOO HIGH AS GUIDANCE IS PROBABLY
KEYING ON THE VERY HIGH RH VALUES (WHICH ARE VERY HIGH FOR THE
AREA AT THIS TIME OF YEAR). FOR THIS EVENING...WILL JUST GO WITH
SLIGHT CHANCE POPS WESTERN AREAS (ECHOES SHOWING UP NOW ALBEIT
WEAK ONES AND MAY NOT LAST)...WITH RAIN CHANCES SHIFTING TOWARD
THE WATERS AND COAST OVERNIGHT TONIGHT. HRRR 4KM MODEL IS SHOWING
ANY ACTIVITY IN OUR CWFA THIS EVENING OUT BY 02Z (IF NOT EARLIER).
ONE MORE DAY OF ISOLATED TO SCATTERED CONVECTION EASTERN AREAS
ON THURSDAY...WITH BETTER CHANCES FOR CONVECTION FARTHER WEST MORE
PROXIMATE TO UPPER LOW. FOR THURSDAY NIGHT...WILL GO WITH LOW END
CHANCE POPS ALONG THE RIO GRANDE...WITH SLIGHT CHANCE REMAINDER
OF WESTERN FOUR COUNTIES. WITH MOISTURE VALUES SO HIGH AND
REMAINING SO FOR THE NEXT THREE PERIODS...SAW NO NEED TO SWAY TOO
MUCH FROM A PERSISTENCE FORECAST AT THIS TIME...ALTHOUGH DID GO A
BIT WARMER THURSDAY NIGHT THAN TONIGHT OUT WEST WHERE MOISTURE AND
CLOUDS WILL LINGER THE LONGEST.
&&
.MARINE (TONIGHT THROUGH THURSDAY NIGHT)...EXPECTING RAINFALL
ACTIVITY IN THE WATERS TO PICK UP SOME AFTER MIDNIGHT...WITH
ISOLATED TO SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS BY SUNRISE.
ACTIVITY SHOULD DECREASE/DIMINISH THURSDAY AFTERNOON...WITH
COVERAGE EVEN LOWER THURSDAY NIGHT (AND MAINLY SOUTH) AS THE
MOISTURE AXIS BEGINS TO SHIFT NORTHWEST.
&&
.LONG TERM (FRIDAY THROUGH WEDNESDAY)...EXTENDED PERIOD BEGINS WITH
UNSETTLED WEATHER GRADUALLY ENDING AS A SLOW MOVING UPPER LOW
FINALLY BEGINS TO ROTATE NORTH OF THE AREA. PWATS REMAIN HIGH INTO
THE EVENING ON FRIDAY BUT WITH UPPER SUPPORT LEAVING AND A BUILDING
GULF RIDGE BRINGING DRIER AIR OVER THE EAST WILL CONFINE POPS TO THE
WESTERN COUNTIES.
UPPER RIDGE WILL CONTINUE TO BROADEN AND EXPAND OVER THE WEEKEND AND
EARLY NEXT WEEK IN RESPONSE TO AN UPPER LOW DROPPING INTO THE
PACIFIC NORTHWEST. EXPECT CONDITIONS TYPICAL OF SUMMERTIME RIDGES
WITH TEMPERATURES SLIGHTLY ABOVE NORMAL AND HEAT INDICES COMMONLY
BETWEEN 105 AND 109 IN THE AFTERNOONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 80 95 80 96 76 / 20 30 10 10 10
VICTORIA 75 93 75 94 75 / 10 20 10 10 10
LAREDO 76 95 77 100 80 / 20 40 30 20 20
ALICE 75 94 76 98 76 / 10 30 10 10 10
ROCKPORT 80 91 80 92 78 / 10 30 10 10 10
COTULLA 74 94 75 94 76 / 20 30 20 20 20
KINGSVILLE 78 95 78 97 76 / 20 30 10 10 10
NAVY CORPUS 79 91 80 92 79 / 20 30 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...SHORT TERM
JV/71...LONG TERM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
401 PM EDT WED JUN 12 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES FROM THE OHIO VALLEY WILL BRING A
CHANCE FOR THUNDERSTORMS TO THE MOUNTAINS LATE THIS AFTERNOON. A
LEE SIDE TROUGH WILL BRING A SLIGHT CHANCE FOR THUNDERSTORMS FOR
AREAS EAST OF THE BLUE RIDGE THIS EVENING. A STRONG COLD FRONT
WILL SWEEP ACROSS THE REGION TOMORROW. STRONG TO SEVERE STORMS
WILL ACCOMPANY THE FRONT.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 356 PM EDT WEDNESDAY...
A FEW REMNANT STORMS ENTERED THE MOUNTAINS FROM THE OHIO RIVER
VALLEY THIS MORNING AND EARLY AFTERNOON. THESE STORMS FELL APART
MOVING TOWARD THE BLUE RIDGE. THE 06/12 18Z HRRR HAS THE BEST HANDLE
ON CONVECTION LATE THIS AFTERNOON WITH BEST CHANCE SOUTH OF A LINE
FROM BLUEFIELD WV TO MOUNT AIRY NC. THESE SHOWERS SHOULD FADE WITH
LOSE OF HEATING.
THE FOCUS OVERNIGHT INTO TOMORROW WILL BE A FAST MOVING COLD FRONT.
THIS FRONT HAS GOOD DYNAMIC AND MOISTURE TO WORK WITH AND WILL
LIKELY BRING SEVERE WEATHER INTO THE REGION. THE MAIN THREAT WITH
THIS FRONT WILL BE STRAIGHT LINE WINDS. SOME METEOROLOGIST ARE
COMPARING THIS FRONT TO THE DERECHO OF JUNE 2012. THERE ARE SEVERAL
DIFFERENCES BETWEEN THE TWO. THE MAIN DIFFERENCE IS THAT THIS FRONT
WILL BE ENTERING THE AREA DURING THE MORNING THEN JUMPING TO A LEE
TROUGH IN THE EAST BY EARLY AFTERNOON. THUNDERSTORMS LIKE TO FEED
OFF OF HEAT WHICH IS LACKING IN THE MORNING. THE FRONT MAY NOT JUMP
TO THE LEE TROUGH UNTIL THE AFTERNOON WHICH WILL ALLOW THE SW VA
PIEDMONT...SOUTHSIDE VA...AND NORTHERN NC PIEDMONT TO WARM INTO THE
LOWER 90S. THIS AREA WILL HAVE THE GREAT POTENTIALLY FOR BLACKSBURG
CWA TO HAVE SEVERE WEATHER. LAST YEAR`S DERECHO MOVED INTO A VERY
WARM ENVIRONMENT OF 90F TO 105F LATE IN THE AFTERNOON/EARLY EVENING.
ALSO WITH THIS FRONT...A WEST WIND WILL BE ESTABLISHED EARLY.
SHOWERS AND THUNDERSTORMS WILL MOVING INTO THE MOUNTAINS AND
POSSIBLY FADE TOWARD THE BLUE RIDGE DURING THE MORNING. AS THE FRONT
JUMPS TO THE LEE TROUGH...A LINE OF CONVECTION WILL DEVELOP OVER THE
PIEDMONT. THIS SYSTEM SHOULD EXIT THE AREA BY RUSH HOUR TOMORROW
EVENING.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 230 PM EDT WEDNESDAY...
GOING TO SEE SHOWERS AND STORMS EXITING THE EASTERN CWA BY THURSDAY
EVENING WITH LINGERING SHOWERS ACROSS THE WESTERN SLOPES AS ANOTHER
PIECE OF SHORTWAVE ENERGY FOLLOWS THE MAIN FRONT. THINK THE
SUBSIDENCE BEHIND THE CONVECTION TO WORK IN DRIER AIR AND CLEAR
SKIES OUT BY LATE THURSDAY NIGHT IN MOST OF THE REGION...LINGERING
CLOUDS ACROSS THE WESTERN SLOPES OF SE WV.
THERE IS YET ANOTHER SHORTWAVE PUSHING SOUTHEAST ACROSS THE MTNS
FRIDAY ALTHOUGH MOISTURE APPEARS LIMITED. CANNOT RULE OUT A FEW
SPRINKLES OR LIGHT RAIN SHOWERS IN THE MTNS OF SE WV/ALLEGHANY
HIGHLANDS OF VA.
THE AIRMASS WILL BE DRIER FOR PERIOD OF 48 HOURS WHILE SFC HIGH
BUILDS OVERHEAD BY SATURDAY. TEMPS WILL BE A FEW DEGREES COOLER THAN
NORMAL FRIDAY WITH HIGHS RANGING FROM THE LOWER 70S WEST TO LOWER
80S EAST...FOLLOWED BY LOWS FRIDAY NIGHT FROM AROUND 50 WEST TO MID
50S EAST.
THERE SHOULD BE ENOUGH GRADIENT THU NIGH-FRIDAY FOR SOME BREEZY
CONDITIONS...GUSTS UP TO 25 MPH.
SATURDAY WILL BE DRY AND SEASONAL WITH HIGHS RANGING FROM THE MID TO
UPPER 70S WEST TO LOWER TO MID 80S EAST.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 115 PM EDT WEDNESDAY...
EXPECT ANOTHER ACTIVE PERIOD AT LEAST FOR SUNDAY NIGHT-TUESDAY AS
ANOTHER FRONT MAKES ITS WAY TOWARD AND THROUGH THE AREA.
SUNDAY...LOOKING AT HIGH PRESSURE MOVING OFFSHORE SETTING OUR AREA
UP IN THE RETURN FLOW AND INCREASED HUMIDITY. SUNDAY WILL BE A DAY
OF TYPICAL SHOWER/STORM DEVELOPMENT IN THE MTNS.
AS WE HEAD INTO MONDAY-TUESDAY...FRONTAL SYSTEM MOVES FROM GREAT
LAKES-CENTRAL PLAINS SOUTHEAST INTO THE MID ATLANTIC SOUTHWEST TO
THE LOWER OHIO VALLEY. MODELS SIMILAR OVERALL BUT TIMING INDIVIDUAL
CLUSTERS OF SHORTWAVES WILL BE PROBLEMATIC. STILL LOOKS LIKE AN
ACTIVE PATTERN WHERE 2-3 ROUNDS OF SHOWERS/STORMS WILL MOVE ACROSS.
FRONT APPEARS TO FINALLY INCH SOUTHEAST OF OUR AREA BY WEDNESDAY
WITH DRIER AIR MOVING IN FOR AT LEAST ONE OR TWO DAYS.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
AS OF 140 PM EDT WEDNESDAY...
SCATTERED THUNDERSTORMS WERE MOVING SOUTHEAST ACROSS SOUTHEAST
WEST VIRGINIA AND SOUTHWEST VIRGINIA EARLY THIS AFTERNOON. HAVE
ADDED THUNDERSTORMS IN THROUGH 20Z FOR THE BLF TAF. SEEING SOME
DEVELOPMENT STILL TO THE NORTHWEST SO OCCURRENCE OF THUNDER MAY
NEED TO BE PROLONGED AT BLF AND ADDED TO LWB LATER THIS AFTERNOON
INTO EARLY EVENING. OTHERWISE EXPECT ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS IN THE LEE OF THE APPALACHIANS LATE THIS
AFTERNOON AND EVENING. AT THIS TIME THE CHANCE IS LOW ENOUGH TO
KEEP OUT OF THE TAFS.
A FRONT WILL BRING A PERIOD OF SUB-VFR CONDITIONS TO THE AREA
LATE TONIGHT AND THURSDAY MORNING...ASSOCIATED WITH AN ORGANIZED
AREA OF SHOWERS/THUNDERSTORMS. STRONG GUSTY WINDS ARE POSSIBLE
WITH THE THUNDERSTORMS...ESPECIALLY AT DAN AND LYH THURSDAY
AFTERNOON.
HIGH PRESSURE WILL BUILD IN FRIDAY AND SATURDAY RESULTING IN VFR
WEATHER. COULD SEE FOG AT THE TYPICAL LOCATIONS SUNDAY MORNING...
LWB/BCB...OTHERWISE VFR. SEEING RETURN FLOW OFF THE ATLANTIC
SUNDAY WITH A FRONT MOVING INTO THE MIDWEST/GREAT LAKES. A 20
PERCENT CHANCE OF THUNDERSTORMS SUNDAY AFTERNOON IN THE AREA AS
WELL.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...RCS
NEAR TERM...RCS
SHORT TERM...WP
LONG TERM...WP
AVIATION...AMS/RCS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
957 PM CDT THU JUN 13 2013
.UPDATE...
QUIET WEATHER WITH HIGH PRESSURE SETTELING IN. FOG POTENTIAL WITH
CLEAR SKIES AND MOIST CONDITIONS WITH RECENT RAINS WILL BE OFFSET
BY WEAK DRY ADVECTION AND WEAK AND SHALLOW INVERSION ON LATEST RAP
SOUNDINGS ALLOWING SOME STIRRING WITH 12 TO 15 KT WINDS AROUND
550 FT MIXING DOWN AT TIMES. LOWEST DEW POINT DEPRESSIONS ARE IN
THE 1 TO 2 DEGREE RANGE...AND WILL PROBABLY SEE SOME SHALLOW
GROUND FOG...BUT NOT ENOUGH CONFIDENCE TO ADD TO FORECAST.
&&
.AVIATION/06Z TAFS/...
QUIET WEATHER AND VFR CONDITIONS THROUGH THE FORECAST. LATEST NAM
IN AGREEMENT WITH 12Z WRF MODELS IN BRINGING PRECIPITATION CLOSE
TO...BUT STILL WEST OF KMKE THROUGH 12Z SATURDAY. WILL LEAVE OUT
OF KMKE TAF FOR NOW. CONCERN FOR DEVELOPMENT OF PATCHY FOG WITH
CLEAR SKIES AND LIGHT WINDS...ESPECIALLY WITH RECENT HEAVY RAINS
ADDING TO LOW-LEVEL MOISTURE. LATEST RAP SOUNDINGS INDICATE THE
LOWEST DEW POINT DEPRESSIONS ARE IN THE 1 TO 2 DEGREE RANGE WITH
A WEAK AND SHALLOW INVERSION ALLOWING SOME STIRRING WITH 12 TO 15
KT WINDS AROUND 550 FT MIXING DOWN AT TIMES. WILL SEE SOME SHALLOW
GROUND FOG...BUT NOT ENOUGH CONFIDENCE TO ADD TO ANY OF THE TAF
SITES.
&&
.PREV DISCUSSION... /ISSUED 325 PM CDT THU JUN 13 2013/
VERY SHORT TERM...TONIGHT AND FRIDAY.
HIGH PRESSURE WILL BRING CONTINUED QUIET WEATHER THROUGH THE DAY
FRIDAY. THE AXIS OF THE HIGH WILL COME OVERHEAD TONIGHT...RESULTING
IN LIGHT WINDS AND MOSTLY CLEAR SKIES. COULD SEE SOME PATCHY FOG
DEVELOP GIVEN THESE CONDITIONS AND THE RECENT RAINFALL. GIVEN SOME
LIGHT WIND IN THE LOW LEVELS AND HOW SHORT THE NIGHTS ARE THIS TIME
OF THE YEAR THOUGH...OPTED TO LEAVE FOG OUT OF THE FORECAST.
SHOULD BE A PLEASANT DAY FRIDAY...WITH MOSTLY SUNNY SKIES AND NEAR
NORMAL TEMPERATURES. HIGH CLOUDS WILL PROBABLY INCREASE LATE
AFTERNOON IN THE WEST AHEAD OF THE NEXT APPROACHING SYSTEM.
ALSO...TEMPERATURES WILL BE COOLER ONCE AGAIN NEAR LAKE MICHIGAN
UNDER ONSHORE WINDS.
SHORT TERM...FRIDAY NIGHT THROUGH SUNDAY.
PWAT VALUES DOUBLE FRIDAY NIGHT AS LOW LEVEL RETURN FLOW STRENGTHENS
AHEAD OF PIECE OF SHORT WAVE ENERGY GETTING EJECTED NORTHEASTWARD
AHEAD OF STRONGER UPSTREAM WAVE OVER SRN CANADA/MONTANA. BEST
CONVERGENCE ASSOCIATED WITH LOW LEVEL JET AFFECTS SOUTHEAST
MN/EASTERN IA BEFORE LLJ PIVOTS AND WEAKENS LATE FRI NIGHT.
STRONGEST LOW LEVEL WAA REMAINS OVER IA BUT A SMALL AREA CLIPS
SOUTHWEST WI. HENCE WL CONTINUE HIGH POPS IN THIS AREA...TRAILING
OFF TO LOW CHANCE POPS IN THE EAST.
LOW LEVEL JET REMAINS MOSTLY SOUTH OF THE AREA THROUGH
SUNDAY...HOWEVER DOES REENERGIZE ACROSS NRN IL SAT NGT. SHORT TERM
GUIDANCE IN GOOD AGREEMENT ON MID-LEVEL SHORT WAVE...POSSIBLY
CONVECTIVELY GENERATED...MOVING ACROSS THE AREA LATER SAT AFTN AND
EVENING. IN ADDITION...ENHANCED SYNOPTIC SCALE FORCING EXPECTED SAT
NIGHT FROM PASSING RIGHT EXIT REGION OF UPPER JET. WL CONTINUE
HIGHER POPS ACROSS THE SOUTH DURING THE EVENING.
SIGNS POINT TO FRONTAL BOUNDARY ACROSS ILLINOIS GETTING NUDGED
FURTHER SOUTHWARD ON SUNDAY BUT STILL SOME LINGERING INSTABILITY
DURING THE DAY. WOULD NOT BE SURPRISED IF MOST OF SUNDAY WAS DRY BUT
FOR NOW KEPT SMALL POPS GOING THROUGH THE DAY.
LONG TERM...SUNDAY NIGHT THROUGH THURSDAY.
MEDIUM RANGE GUIDANCE IN AGREEMENT ON CARRYING MORE AMPLIFIED SHORT
WAVE TROUGH ACROSS THE WESTERN GREAT LAKES SUNDAY NIGHT AND MONDAY.
THIS FEATURES CARRIES SLIGHTLY STRONGER COLD FRONT ACROSS SOUTHERN
WI DURING THIS PERIOD. EARLIER DETERMINISTIC GFS FASTER WITH FRONT
PASSAGE HOWEVER...12Z GUIDANCE IN BETTER AGREEMENT WITH OTHER SLOWER
GUIDANCE...WHICH HAS FRONT PASSING THROUGH ON MONDAY. DEPENDING UPON
AVAILABLE MOISTURE...CONSIDERING STRENGTH OF ACCOMPANYING SHORT
WAVE...SCATTERED TO NUMEROUS CONVECTION MAY AFFECT SRN WI ON MON.
SHORT WAVE SPEEDS OFF TO THE EAST LATER MONDAY WITH COOLER...DRIER
AIR SETTLING IN FOR TUESDAY. GFS INDICATING SMALL POTENTIAL FOR
INSTABILITY -SHRA ON TUE HOWEVER OTHER MEDIUM RANGE GUIDANCE MORE
BULLISH ON HIGH PRESSURE RIDGING AND SUBSIDENCE NUDGING INTO THE
AREA ON TUE. GFS SOUNDINGS TUE AFT ALSO APPEAR FAIRLY DRY ABV 3-4K
FEET. HENCE WL REMOVE SMALL POPS FOR TUE.
FOR LATER PERIODS...BOTH GFS AND ECMWF DEPICTING MORE AMPLIFIED
RIDGE OVER WRN GTLAKES THRU THURSDAY...WITH RETURN SLY FLOW
DEVELOPING THU NIGHT. DAYTIME TEMPERATURES SHOULD RISE TO AROUND
NORMAL FOR MID-JUNE WITH THE LAKE BREEZE KEEPING LAKESHORE TEMPS
COOLER IN THE AFTN.
AVIATION /00Z TAFS/...QUIET WEATHER IS EXPECTED THROUGH FRIDAY
UNDER HIGH PRESSURE. THE AXIS OF THE HIGH WILL COME OVERHEAD
TONIGHT...RESULTING IN LIGHT WINDS AND MOSTLY CLEAR SKIES. COULD SEE
SOME PATCHY FOG DEVELOP GIVEN THESE CONDITIONS AND THE RECENT
RAINFALL. GIVEN SOME LIGHT WIND NEAR THE SURFACE AND HOW SHORT THE
NIGHTS ARE THIS TIME OF THE YEAR...CONFIDENCE IS NOT VERY HIGH IN
ANY FOG DEVELOPMENT...SO WILL CONTINUE TO LEAVE OUT OF TAFS.
MARINE...
WINDS CONTINUE TO SLOWLY EASE THIS AFTERNOON AND WAVES ARE ALSO
DIMINISHING. THE SMALL CRAFT ADVISORY HAS THUS BEEN CANCELLED.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...REM
TONIGHT/FRIDAY AND AVIATION/MARINE...DDV
FRIDAY NIGHT THROUGH THURSDAY...MBK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
530 PM CDT WED JUN 12 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 314 PM CDT WED JUN 12 2013
AT 3 PM...WATER VAPOR IMAGERY AND VAD WIND PROFILERS SHOW A
STRONG NEGATIVELY TITLED TROUGH MOVING EAST OUT OF EASTERN SOUTH
DAKOTA. THE RAP HAS AN ANOMALOUSLY STRONG PV ANOMALY EXTENDING
DOWN TO 500 MB. A 850 MB TROUGH IS CURRENTLY MOVING THROUGH THE
WESTERN PORTIONS OF THE FORECAST AREA. MEANWHILE A 700 MB TROUGH
WAS LOCATED ACROSS NORTHWEST IOWA AND SOUTHWEST MINNESOTA. A FEW
SHOWERS HAVE DEVELOPED ACROSS NORTHEAST IOWA AND NEAR LA CROSSE.
MEANWHILE FURTHER TO THE NORTH...A BAND OF SHOWERS AND
THUNDERSTORMS IN AN AREA OF MODERATE TO STRONG 900 TO 700 MB
FRONTOGENESIS.
BOTH THE RAP AND GFS SHOW THAT THE VERY STRONG PV ANOMALY WILL
MOVE EAST SOUTHEAST THROUGH THE FORECAST AREA LATE THIS AFTERNOON
AND EARLY THIS EVENING. AS IT APPROACHES...WE EXPECT TO RAPID
ASCENT TAKE PLACE ACROSS THE AREA WITHIN THE NEXT 2 HOURS. THE
LAPS IS SHOWING A LOW OVER EAST-CENTRAL IOWA. HOWEVER LOOKING AT
THE WIND FIELDS AND THE APPROACHING PV ANOMALY EXPECT THAT THE
ACTUAL LOW OVER NORTH-CENTRAL IOWA WILL BECOME THE PRIMARY SURFACE
LOW. WITH THIS IN MIND...EXPECT THE WARM FRONT TO POTENTIALLY LIFT
A BIT FURTHER NORTH THIS AFTERNOON. POSSIBLY AS FAR NORTH AS THE
INTERSTATE 90 CORRIDOR. REGARDLESS OF THE SURFACE LOW...THE 0-6KM
SHEAR IS FAVORABLE FOR THE DEVELOPMENT OF RIGHT-MOVING SUPERCELLS
ALONG AND SOUTH OF THE INTERSTATE 90 CORRIDOR. THE 0-1 KM HELICITY
IS FAVORABLE ALONG THE WARM FRONT FOR THE DEVELOPMENT OF STRONG
TORNADOES ESPECIALLY ACROSS FAYETTE AND CLAYTON COUNTIES IN
NORTHEAST IOWA AND GRANT COUNTY IN SOUTHWEST WISCONSIN. THE HRRR
CONTINUES TO GENERATE QUITE A FEW SUPERCELLS ALONG AND SOUTH OF
INTERSTATE 90 BETWEEN 12.19Z AND 13.02Z. ALSO EXPECT TO SEE LARGE
HAIL /DUE TO THE FAT CAPE/...DAMAGING WINDS /DCAPES OVER
1000 J/KG/...AND VERY EFFICIENT RAIN PRODUCERS /1.8 PRECIPITABLE
WATER AND WARM CLOUD DEPTHS OVER 4 KM/.
AS THE COLD POOLS EVOLVE LATE THIS AFTERNOON AND EARLY EVENING...
EXPECT A LINE OF STORMS WILL DEVELOP SOMEWHERE ALONG AND EAST OF
THE MISSISSIPPI RIVER. THIS LINE WILL THEN MOVE QUICKLY EAST AS A
DERECHO THROUGH SOUTHERN WISCONSIN...NORTHERN ILLINOIS...
INDIANA...OHIO...AND POSSIBLY SOUTHWEST LOWER MICHIGAN.
IN THE WAKE OF THIS PV ANOMALY...EXPECT HIGH PRESSURE TO QUICKLY
BUILD ACROSS THE AREA. THIS WILL PROVIDE DRY WEATHER FOR LATE
TONIGHT AND THURSDAY. HIGH TEMPERATURES ON THURSDAY WILL BE IN THE
LOWER AND MID 70S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 314 PM CDT WED JUN 12 2013
ON FRIDAY AFTERNOON AND NIGHT...THE 850 MB MOISTURE TRANSPORT WILL
RAPIDLY INCREASE ACROSS THE FORECAST AREA AS A SHORTWAVE TROUGH
ROUNDS THE UPPER LEVEL RIDGE. THE LOW LEVEL JET WILL BRING 1 TO
2K J/KG MU CAPE INTO THE FORECAST AREA. WHILE THE 0-6 KM SHEAR IS
NOT SUFFICIENT FOR SUPERCELLS...THE 0-3 KM SHEAR DOES SUGGEST THE
POTENTIAL FOR SOME ISOLATED AREAS OF DAMAGING WINDS. WITH WARM
CLOUD LAYER DEPTHS ABOVE 4 KM AND PRECIPITABLE WATER VALUES UP TO
1.6 INCHES...THE STORMS WILL HIGHLY EFFICIENT AT PRODUCING RAIN...
THUS...WILL HAVE TO WATCH OUT FOR THE POTENTIAL FOR SOME
LOCALIZED FLOODING ON FRIDAY NIGHT.
ON SATURDAY NIGHT AND SUNDAY...THE MODELS SHOW THAT A MESOSCALE
CONVECTIVE COMPLEX WILL DEVELOP OVER SOUTH DAKOTA AND NEBRASKA.
THIS SYSTEM LOOKS LIKE IT WILL TRACK WILL MAINLY AFFECT AREAS
SOUTH OF THE INTERSTATE 90 CORRIDOR. WITH THE 0-6KM SHEAR LESS
THAN 40 KNOTS...NOT EXPECTING ANY SEVERE WEATHER AT THIS TIME.
BEYOND THIS TIME PERIOD...THE MODELS CONTINUE TO STRUGGLE WITH THE
TIMING AND POSITION SHORT WAVE TROUGHS THROUGH THE REGION...THUS
JUST STAYED WITH THE ALL BLEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 530 PM CDT WED JUN 12 2013
INSTABILITY AND A GOOD MOISTURE FEED WILL FUEL SHOWERS AND STORMS AS
A SHORTWAVE TROUGH DROPS SOUTHEAST ACROSS THE REGION EARLY THIS
EVENING. MANY OF THESE HAVE BEEN STRONG TO SEVERE...BUT THIS
ACTIVITY WAS SOUTH OF KRST/KLSE. EXPECTING THE BULK OF THE
SHRA/TS TO BE SOUTH OF KRST/KLSE BY 02Z OR SO. HIGH PRESSURE
THEN BUILDS IN...CLEARING THE SKIES OVERNIGHT. BUFKIT SOUNDINGS
SUGGEST AFTERNOON CU DEVELOPMENT FOR THU...BUT CONDITIONS SHOULD
STAY VFR - AFTER THE SHRA/TS EXIT SOUTHEAST EARLY THIS EVENING.
&&
.HYDROLOGY...
ISSUED AT 314 PM CDT WED JUN 12 2013
WITH HIGH PRECIPITABLE WATER VALUES AND WARM CLOUD LAYER DEPTHS
ABOVE 4 KM...THE STORMS THIS AFTERNOON AND EVENING AND ON FRIDAY
NIGHT WILL VERY EFFICIENT RAIN PRODUCERS. AS A RESULT...THERE IS
SOME CONCERN THAT THERE COULD BE SOME LOCALIZED FLASH FLOODING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM....BOYNE
AVIATION.....RIECK
HYDROLOGY....BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
315 PM CDT WED JUN 12 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 314 PM CDT WED JUN 12 2013
AT 3 PM...WATER VAPOR IMAGERY AND VAD WIND PROFILERS SHOW A
STRONG NEGATIVELY TITLED TROUGH MOVING EAST OUT OF EASTERN SOUTH
DAKOTA. THE RAP HAS AN ANOMALOUSLY STRONG PV ANOMALLY EXTENDING
DOWN TO 500 MB. A 850 MB TROUGH IS CURRENTLY MOVING THROUGH THE
WESTERN PORTIONS OF THE FORECAST AREA. MEANWHILE A 700 MB TROUGH
WAS LOCATED ACROSS NORTHWEST IOWA AND SOUTHWEST MINNESOTA. A FEW
SHOWERS HAVE DEVELOPED ACROSS NORTHEAST IOWA AND NEAR LA CROSSE.
MEANWHILE FURTHER TO THE NORTH...A BAND OF SHOWERS AND
THUNDERSTORMS IN AN AREA OF MODERATE TO STRONG 900 TO 700 MB
FRONTOGENESIS.
BOTH THE RAP AND GFS SHOW THAT THE VERY STRONG PV ANOMALY WILL
MOVE EAST SOUTHEAST THROUGH THE FORECAST AREA LATE THIS AFTERNOON
AND EARLY THIS EVENING. AS IT APPROACHES...WE EXPECT TO RAPID
ASCENT TAKE PLACE ACROSS THE AREA WITHIN THE NEXT 2 HOURS. THE
LAPS IS SHOWING A LOW OVER EAST-CENTRAL IOWA. HOWEVER LOOKING AT
THE WIND FIELDS AND THE APPROACHING PV ANOMALY EXPECT THAT THE
ACTUAL LOW OVER NORTH-CENTRAL IOWA WILL BECOME THE PRIMARY SURFACE
LOW. WITH THIS IN MIND...EXPECT THE WARM FRONT TO POTENTIALLY LIFT
A BIT FURTHER NORTH THIS AFTERNOON. POSSIBLY AS FAR NORTH AS THE
INTERSTATE 90 CORRIDOR. REGARDLESS OF THE SURFACE LOW...THE 0-6KM
SHEAR IS FAVORABLE FOR THE DEVELOPMENT OF RIGHT-MOVING SUPERCELLS
ALONG AND SOUTH OF THE INTERSTATE 90 CORRIDOR. THE 0-1 KM HELICITY
IS FAVORABLE ALONG THE WARM FRONT FOR THE DEVELOPMENT OF STRONG
TORNADOES ESPECIALLY ACROSS FAYETTE AND CLAYTON COUNTIES IN
NORTHEAST IOWA AND GRANT COUNTY IN SOUTHWEST WISCONSIN. THE HRRR
CONTINUES TO GENERATE QUITE A FEW SUPERCELLS ALONG AND SOUTH OF
INTERSTATE 90 BETWEEN 12.19Z AND 13.02Z. ALSO EXPECT TO SEE LARGE
HAIL /DUE TO THE FAT CAPE/...DAMAGING WINDS /DCAPES OVER
1000 J/KG/...AND VERY EFFICIENT RAIN PRODUCERS /1.8 PRECIPITABLE
WATER AND WARM CLOUD DEPTHS OVER 4 KM/.
AS THE COLD POOLS EVOLVE LATE THIS AFTERNOON AND EARLY EVENING...
EXPECT A LINE OF STORMS WILL DEVELOP SOMEWHERE ALONG AND EAST OF
THE MISSISSIPPI RIVER. THIS LINE WILL THEN MOVE QUICKLY EAST AS A
DERECHO THROUGH SOUTHERN WISCONSIN...NORTHERN ILLINOIS...
INDIANA...OHIO...AND POSSIBLY SOUTHWEST LOWER MICHIGAN.
IN THE WAKE OF THIS PV ANOMALY...EXPECT HIGH PRESSURE TO QUICKLY
BUILD ACROSS THE AREA. THIS WILL PROVIDE DRY WEATHER FOR LATE
TONIGHT AND THURSDAY. HIGH TEMPERATURES ON THURSDAY WILL BE IN THE
LOWER AND MID 70S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 314 PM CDT WED JUN 12 2013
ON FRIDAY AFTERNOON AND NIGHT...THE 850 MB MOISTURE TRANSPORT WILL
RAPIDLY INCREASE ACROSS THE FORECAST AREA AS A SHORTWAVE TROUGH
ROUNDS THE UPPER LEVEL RIDGE. THE LOW LEVEL JET WILL BRING 1 TO
2K J/KG MU CAPE INTO THE FORECAST AREA. WHILE THE 0-6 KM SHEAR IS
NOT SUFFICIENT FOR SUPERCELLS...THE 0-3 KM SHEAR DOES SUGGEST THE
POTENTIAL FOR SOME ISOLATED AREAS OF DAMAGING WINDS. WITH WARM
CLOUD LAYER DEPTHS ABOVE 4 KM AND PRECIPITABLE WATER VALUES UP TO
1.6 INCHES...THE STORMS WILL HIGHLY EFFICIENT AT PRODUCING RAIN...
THUS...WILL HAVE TO WATCH OUT FOR THE POTENTIAL FOR SOME
LOCALIZED FLOODING ON FRIDAY NIGHT.
ON SATURDAY NIGHT AND SUNDAY...THE MODELS SHOW THAT A MESOSCALE
CONVECTIVE COMPLEX WILL DEVELOP OVER SOUTH DAKOTA AND NEBRASKA.
THIS SYSTEM LOOKS LIKE IT WILL TRACK WILL MAINLY AFFECT AREAS
SOUTH OF THE INTERSTATE 90 CORRIDOR. WITH THE 0-6KM SHEAR LESS
THAN 40 KNOTS...NOT EXPECTING ANY SEVERE WEATHER AT THIS TIME.
BEYOND THIS TIME PERIOD...THE MODELS CONTINUE TO STRUGGLE WITH THE
TIMING AND POSITION SHORT WAVE TROUGHS THROUGH THE REGION...THUS
JUST STAYED WITH THE ALL BLEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1214 PM CDT WED JUN 12 2013
A VIGOROUS UPPER LEVEL DISTURBANCE WILL BRING SHOWERS AND
THUNDERSTORMS TO THE TAF SITES THIS AFTERNOON INTO EARLY THIS
EVENING. A FEW STORMS COULD BECOME SEVERE WITH LARGE
HAIL...DAMAGING WINDS. AN ISOLATED TORNADO IS ALSO POSSIBLE BUT
THE HIGHER CHANCES WILL BE ACROSS NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN. MVFR TO IFR CONDITIONS ARE POSSIBLE IN THE
THUNDERSTORMS THIS AFTERNOON. A COLD FRONT WILL PUSH ACROSS THE
AREA THIS EVENING WITH WINDS SWITCHING TO THE NORTHWEST. AFTER A
BRIEF PERIOD OF MVFR STRATUS RIGHT BEHIND THE FRONT...VFR
CONDITIONS ARE EXPECTED LATE TONIGHT INTO THURSDAY MORNING.
&&
.HYDROLOGY...
ISSUED AT 314 PM CDT WED JUN 12 2013
WITH HIGH PRECIPITABLE WATER VALUES AND WARM CLOUD LAYER DEPTHS
ABOVE 4 KM...THE STORMS THIS AFTERNOON AND EVENING AND ON FRIDAY
NIGHT WILL VERY EFFICIENT RAIN PRODUCERS. AS A RESULT...THERE IS
SOME CONCERN THAT THERE COULD BE SOME LOCALIZED FLASH FLOODING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...WETENKAMP
HYDROLOGY...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1214 PM CDT WED JUN 12 2013
.UPDATE...
ISSUED AT 1214 PM CDT WED JUN 12 2013
INCREASING THREAT FOR SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE
FORECAST AREA THIS AFTERNOON. THE HIGHEST CHANCES FOR SEVERE
THUNDERSTORMS WILL BE ALONG AND SOUTH OF THE INTERSTATE 94 CORRIDOR.
DAMAGING WINDS...LARGE HAIL...AND A FEW TORNADOES ARE POSSIBLE
THIS AFTERNOON...ESPECIALLY ACROSS NORTHEAST IOWA INTO FAR
SOUTHWEST WISCONSIN. FAYETTE...CLAYTON...AND GRANT COUNTIES HAVE
THE HIGHEST CHANCES OF SEEING A TORNADO THIS AFTERNOON. A LARGE
TORNADO OR TWO IS POSSIBLE...ESPECIALLY NORTHEAST OF THE SURFACE
LOW.
AT THIS TIME...A POTENT SHORTWAVE WAS DRIVING SOUTHEAST ACROSS
EASTERN SOUTH DAKOTA/SOUTHWEST MINNESOTA AND LOOKED RATHER
IMPRESSIVE ON WATER VAPOR. MEANWHILE...SURFACE LOW PRESSURE WAS
DEEPENING OVER CENTRAL IOWA WITH A WARM FRONT EXTENDING FROM
CENTRAL IOWA EAST ACROSS NORTHERN ILLINOIS. THE LOW WILL LIFT
NORTHEAST THIS AFTERNOON PULLING THE WARM FRONT NORTH INTO
NORTHEAST IOWA/SOUTHWEST WISCONSIN. MEANWHILE...THE SHORTWAVE WILL
TRACK SOUTHEAST ACROSS NORTHER IOWA/SOUTHERN MINNESOTA. THE
TIMING OF THE WAVE AND THE PROXIMITY OF THE WARM FRONT...ALONG
WITH INCREASING INSTABILITY....WILL CREATE FAVORABLE CONDITIONS
FOR SEVERE THUNDERSTORMS. 0-6 KM SHEAR OF 60 KTS AND 0-1 KM SHEAR
OF AROUND 20KTS...LOCALLY ENHANCED NEAR THE WARM FRONT/SURFACE
LOW...WILL BE VERY FAVORABLE FOR DISCRETE SUPERCELLS CAPABLE OF
PRODUCING TORNADOES. A FEW STORMS MAY ALSO PRODUCE LOCALIZED FLASH
FLOODING.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 318 AM CDT WED JUN 12 2013
MAIN CONCERN FOR TODAY INTO THIS EARLY EVENING WILL BE SEVERE
THUNDERSTORM THREAT ACROSS THE SOUTH.
WATER VAPOR IMAGERY/RAP 500MB HEIGHT FIELD SHOWS A VIGOROUS
SHORTWAVE TROUGH MOVING OUT OF MT/WY INTO WESTERN ND/SD/NE. SURFACE
MAP AS OF 2 AM HAD AN AREA OF LOW PRESSURE ALONG THE KS/NE BORDER
WITH A WARM FRONT EXTENDING ENE ALONG I-80 IN IA AND IL. 850MB
MOISTURE TRANSPORT/ISENTROPIC LIFT AHEAD OF THE LOW AND OVER THE
WARM FRONT WAS PRODUCING SCATTERED ELEVATED SHRA/TS ACROSS OUR
FORECAST AREA...WITH A MORE INVIGORATED N-S LINE OF STORMS ACROSS
CENTRAL SD WHICH WAS HEADED EAST AROUND 50KT. RAP CORFIDI VECTORS
TAKE THIS COMPLEX OF STORMS DUE EAST AT 55-65KT THIS MORNING...WHICH
WOULD BRING IT INTO OUR AREA IN THE 7-9 AM TIME FRAME. MEANWHILE...A
NEW COMPLEX OF THUNDERSTORMS WERE FIRING ACROSS NORTHWEST
IA...MOVING TOWARD THE EAST. THIS CONVECTION WAS ROOTED A BIT CLOSER
TO THE CAPE POOL JUST NORTH OF THE 925-850MB WARM FRONT. A COUPLE
OBS IN SD WHERE THIS LINE PASSED RECORDED 43/48KT. HOWEVER...WRF
MODELS...NAMELY THE 12.00Z NSSL WRF WHICH SEEMS TO HAVE THE BEST
HANDLE ON THE CONVECTION RIGHT NOW...HAS THIS CONVECTION DECAYING AS
IT MOVES INTO THE AREA IN THE 5-8AM TIME FRAME. WITH 0-3KM BULK
SHEAR IN THE 40-50KT RANGE AND 0-3KM ML MUCAPE HOVERING IN THE
1000-2000J/KG...WILL HAVE TO WATCH THIS ONGOING CONVECTION CAREFULLY
FOR A SEVERE WIND THREAT EARLY THIS MORNING.
THERE THEN SEEMS TO BE A BREAK IN THE ACTION FROM MID-MORNING UNTIL
EARLY AFTERNOON BEFORE THE MID-LEVEL TROUGH AND SURFACE LOW MOVE
ACROSS EASTERN IA IN THE 18Z-21Z TIME FRAME. THIS TROUGH/STEEPENING
MID LEVEL LAPSE RATES THEN INTERACTS WITH 2000-3500J/KG 0-1KM ML
MUCAPE POOL IN PLACE SOUTH OF I-90 TO FIRE VIGOROUS/DEEP
CONVECTION. COOLING MID LEVEL/STEEPER LAPSE RATES AND 0-3KM BULK
SHEAR IN THE 20-40KT RANGE WILL SUPPORT A SEVERE HAIL/WIND THREAT
SOUTH OF I-90. AND...WITH THE JUXTAPOSITION OF THE LOW/WARM FRONT
PRODUCING FAVORABLE 0-3KM SRH...CANNOT RULE OUT A TORNADIC THREAT
ACROSS PORTIONS OF NORTHEAST IA INTO FAR SOUTHWEST WI...NAMELY
FAYETTE AND CLAYTON COUNTIES IN NORTHEAST IA AND GRANT COUNTY IN WI.
LOCALIZED FLOODING IS ALSO A CONCERN WITH THIS CONVECTION AS
PRECIPITABLE WATER VALUES HOVER IN THE 1.5 TO 2 INCH RANGE. SEE
HYDROLOGY SECTION BELOW FOR FURTHER DETAILS ON HEAVY RAIN POTENTIAL
AND IMPACTS. PLAN ON THE LOW AND ASSOCIATED CONVECTION TO MOVE
SOUTHEAST OF THE REGION AROUND MIDNIGHT TONIGHT. HIGH PRESSURE THEN
STARTS NOSING IN AFTER MIDNIGHT FROM THE NORTHERN PLAINS FOR
CLEARING SKIES.
HIGH PRESSURE WILL BE IN CONTROL ON THURSDAY WITH PLEASANT
TEMPERATURES IN THE 70S AND LOWER HUMIDITY LEVELS.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 318 AM CDT WED JUN 12 2013
HIGH PRESSURE REMAINS IN CONTROL ACROSS THE AREA THURSDAY NIGHT
THROUGH FRIDAY MORNING FOR A CONTINUED DRY RESPITE. BY FRIDAY
AFTERNOON THOUGH...A TROUGH OF LOW PRESSURE OVER THE PLAINS BEGINS
TO SHOVE MOISTURE BACK INTO THE AREA...MAINLY WEST OF THE
MISSISSIPPI RIVER FOR A CHANCE OF SHOWERS/ISOLATED THUNDER. FOR
FRIDAY NIGHT THROUGH SATURDAY EVENING...LOOK FOR LOW PRESSURE OVER
CANADA TO SEND A COLD FRONT THROUGH THE AREA. THIS WILL PRODUCE THE
LIKELIHOOD OF SHOWERS AND THUNDERSTORMS. WILL NEED TO WATCH FOR THE
POSSIBILITY OF SEVERE WEATHER GIVEN 0-1KM ML MUCAPE IN THE
1500-3500J/KG AND MODEST AMOUNT OF 0-3KM BULK SHEAR. LINGERING
MID-LEVEL TROUGH/FAIRLY STEEP LAPSE RATES ENOUGH TO WARRANT A
LOWER-END SHRA/TS CHANCE SUNDAY THROUGH MONDAY. NORTHWEST FLOW AND
ANOTHER WEAK MID-LEVEL TROUGH IN THIS FLOW PRODUCE ANOTHER SHRA/TS
CHANCE ON TUESDAY. OTHERWISE... LOOKS LIKE TEMPERATURES WILL BE
RIGHT AROUND NORMAL THROUGH THE PERIOD...MAINLY IN THE 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1214 PM CDT WED JUN 12 2013
A VIGOROUS UPPER LEVEL DISTURBANCE WILL BRING SHOWERS AND
THUNDERSTORMS TO THE TAF SITES THIS AFTERNOON INTO EARLY THIS
EVENING. A FEW STORMS COULD BECOME SEVERE WITH LARGE
HAIL...DAMAGING WINDS. AN ISOLATED TORNADO IS ALSO POSSIBLE BUT
THE HIGHER CHANCES WILL BE ACROSS NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN. MVFR TO IFR CONDITIONS ARE POSSIBLE IN THE
THUNDERSTORMS THIS AFTERNOON. A COLD FRONT WILL PUSH ACROSS THE
AREA THIS EVENING WITH WINDS SWITCHING TO THE NORTHWEST. AFTER A
BRIEF PERIOD OF MVFR STRATUS RIGHT BEHIND THE FRONT...VFR
CONDITIONS ARE EXPECTED LATE TONIGHT INTO THURSDAY MORNING.
&&
.HYDROLOGY...TODAY INTO THIS EVENING
ISSUED AT 318 AM CDT WED JUN 12 2013
FOR AREAS MAINLY ALONG AND SOUTH OF I-90...EXPECTING RAINFALL
AMOUNTS FROM TODAY INTO THIS EVENING IN THE 0.75 TO 1.25 INCH RANGE
WITH THE POSSIBILITY OF LOCALLY HIGHER AMOUNTS IN THUNDERSTORM
ACTIVITY. GIVEN THE WET SOILS IN PLACE...PLAN ON SOME RUNOFF ISSUES
WITH PONDING OF WATER AND SOME SIGNIFICANT WITHIN BANK RIVER RISES.
ANY LONGER DURATION/HIGHER RAINFALL RATES WOULD INCREASE THE
FLOODING POTENTIAL. STAY TUNED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...WETENKAMP
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...WETENKAMP
HYDROLOGY....DAS
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1037 AM CDT WED JUN 12 2013
.UPDATE...THE REMNANTS OF AN MCS CONTINUE TO WEAKEN WHILE MOVING
THROUGH THE EASTERN FORECAST AREA. COULD SEE A FEW SHOWERS OR
STORMS DEVELOP LATE MORNING INTO EARLY AFTERNOON...BUT OTHERWISE
IT LOOKS PRETTY QUIET UNTIL LATER IN THE AFTERNOON.
THE MAIN ISSUE FOR TODAY IS THE POTENTIAL FOR SEVERE
WEATHER...WHICH WILL DEPEND ON EXACTLY WHERE THE WARM FRONT IS
THIS AFTERNOON AND THUS THE BETTER SURFACE BASED INSTABILITY.
SHOWERS AND STORMS SEEM LIKELY EVEN NORTH OF THE FRONT...WITH
AROUND 1000 J/KG OF ELEVATED CAPE. PLENTY OF MOISTURE TO WORK WITH
AS WELL...WITH PRECIPITABLE WATER VALUES PUSHING 2 INCHES. THIS
COULD RESULT IN PRETTY HEAVY RAINFALL WITHIN STORMS.
LOOKING AT LATEST MODELS...THE BULK OF SOLUTIONS KEEP THE WARM
FRONT ALONG OR SOUTH OF THE WI/IL BORDER. EARLIER HRRR RUNS PUSHED
THE WARM FRONT UP TO AROUND MADISON...BUT THE LATEST RUN IS
FARTHER SOUTH SIMILAR TO OTHER MODELS. THE LATEST NAM TAKES
STRONGER SEVERE PARAMETERS INTO THE SOUTHWEST FORECAST AREA THIS
AFTERNOON...SHIFTING IT SOUTH BY EVENING. THOUGH BEST SEVERE
THREAT MAY STAY MAINLY TO THE SOUTH...STILL COULD SEE STRONG TO
SEVERE STORMS ACROSS SOUTHERN WISCONSIN. WILL HAVE THE ELEVATED
INSTABILITY...MAYBE SOME SURFACE BASED IF AREA OF CLEARING TO THE
WEST CAN SLIDE OVER ACROSS SRN WI. ALSO...0-6 KM BULK SHEAR WILL
BE ON THE ORDER OF 40-50 KT. WILL HAVE TO MONITOR THE WARM FRONT
POSITION AND THE AMOUNT OF HEATING THAT OCCURS LATE MORNING INTO
THE AFTERNOON TO CONTINUE TO ASSESS THE SEVERE THREAT.
&&
.AVIATION/18Z TAFS/...COULD SEE A FEW SHOWERS AND STORMS LATE
MORNING INTO THE AFTERNOON...BUT OTHERWISE LOOKS PRETTY QUIET
UNTIL MID OR LATE AFTERNOON AND INTO THE EVENING. EXPECTING
WIDESPREAD SHOWERS AND STORMS TO DEVELOP BY LATER TODAY...WITH A
THREAT FOR SEVERE STORMS. THE BEST CHANCE FOR SEVERE WEATHER LOOKS
TO BE TOWARD AND SOUTH THE ILLINOIS BORDER...BUT THINK THERE WILL
BE ENOUGH ELEVATED INSTABILITY AND SHEAR FOR POTENTIAL STRONG TO
SEVERE STORMS ACROSS SOUTHERN WISCONSIN. CONVECTION SHOULD WIND
DOWN BY LATE EVENING...WITH DRY WEATHER EXPECTED OVERNIGHT AND
TOMORROW AS HIGH PRESSURE MOVES IN.
PREVAILING VFR EXPECTED INTO THE AFTERNOON...WITH LOWER VSBYS
POSSIBLE IN MODERATE TO HEAVY RAINFALL LATER TODAY. COULD SEE
BRIEFLY LOWER CIGS BEHIND EXITING LOW PRESSURE THIS EVENING...BUT
SHOULD SEE A RETURN TO VFR OVERNIGHT AS DRIER AIR MOVES IN.
&&
.PREV DISCUSSION... /ISSUED 250 AM CDT WED JUN 12 2013/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH
ENTRANCE REGION OF 90 KNOT 250 MB JET MAX OVER THE GREAT LAKES IS
ACROSS CENTRAL/SOUTHERN WISCONSIN TODAY BEFORE AN UPPER LEVEL TROUGH
AXIS WITH A TRAILING 90 KNOT JET MAX PUSHES ACROSS NORTHERN ILLINOIS
TONIGHT.
MAINLY WEAK UPPER DIVERGENCE EARLY THIS MORNING BEFORE AN AREA OF
STRONG UPPER DIVERGENCE MOVES ACROSS SOUTHERN WISCONSIN LATER THIS
MORNING. HOWEVER THIS APPEARS TO HAVE SOME CONVECTIVE FEEDBACK FROM
THUNDERSTORMS OVER NORTHWEST IOWA THAT THE NAM PUSHES EAST ACROSS
WISCONSIN. THIS IS ALSO SEEN AS AN AREA OF CYCLONIC VORTICITY AT
500 MB AHEAD OF THE MAIN MID LEVEL SHORTWAVE THAT MOVES ACROSS
NORTHERN ILLINOIS/SOUTHERN WISCONSIN THIS AFTERNOON AND EVENING.
WHILE THE MAIN 700 MB THERMAL RIDGE MOVES ACROSS NORTHERN
ILLINOIS...SOUTHERN WISCONSIN WILL BE IN A MODERATE TEMPERATURE
GRADIENT. WEAK/MODERATE 700 MB UPWARD MOTION EXISTS ACROSS SOUTHERN
WISCONSIN WITH A STRONGER 15 MICROBAR/SEC AREA LATE THIS AFTERNOON
WITH THE MAIN MID LEVEL TROUGH. THE STRONGER 850 MB/700 MB WINDS
SET UP ACROSS NORTHERN ILLINOIS. WEAK TO MODERATE 850 MB MOISTURE
CONVERGENCE OCCURS OVER SOUTHERN WISCONSIN THROUGH THE MORNING WITH
A STRONGER AREA WITH THE SHORTWAVE THIS AFTERNOON.
PRECIPITABLE WATER VALUES REACH ALMOST 2 INCHES BY EARLY EVENING
OVER MUCH OF SOUTHERN WISCONSIN.
THE RAP AND MOST OF THE MESOSCALE MODELS BRING SCATTERED TO NUMEROUS
SHOWERS/THUNDERSTORMS THIS MORNING WITH THE MAIN MCS MOVING ACROSS
NORTHERN ILLINOIS AND PORTIONS OF SOUTHERN WISCONSIN LATER THIS
AFTERNOON. THIS APPEARS REASONABLE.
THE 04Z HRRR TRIES TO DEVELOP THE NORTHWEST IOWA MCS BUT WEAKENS IT
OVER SOUTHERN WISCONSIN THIS MORNING...AND TAKE THE SOUTH DAKOTA MCS
AND WEAKENS IT INTO A MORE WEST TO EAST AREA OF SHOWERS AND
THUNDERSTORMS.
WHAT MAY HAPPEN IS MORE OF A HEAVY RAIN EVENT WITH THE AFTERNOON MCS
FORMED BY THE SYNOPTIC SHORTWAVE AND ASSOCIATED SURFACE LOW. THE
SPC DAY ONE OUTLOOK HAS A MODERATE RISK JUST SOUTH OF THE WISCONSIN
BORDER WITH A SLIGHT RISK OVER SOUTHERN WISCONSIN. THIS AGREES WITH
THE NEW 00Z CIPS ANALOGS THAT PLACE THE MAJORITY OF THE 30 KNOT WIND
PROBABILITIES AND SEVERE REPORTS TO THE SOUTH OF WISCONSIN...WITH A
FEW WIND SEVERE WIND REPORTS IN FAR SOUTHERN WISCONSIN.
THE SHORTWAVE DROPS INTO NORTHERN INDIANA AFTER MIDNIGHT TONIGHT.
EXPECT A SURGE OF NORTH WINDS ESPECIALLY DOWN LAKE MICHIGAN LATE
THIS EVENING AND TONIGHT.
THURSDAY THROUGH FRIDAY...FORECAST CONFIDENCE HIGH.
A HIGH PRESSURE RIDGE WILL BE MOVING ACROSS THE UPPER MIDWEST AND
GREAT LAKES REGION DURING THIS PERIOD. EXPECT SUNSHINE...LOWER
DEWPOINTS AND LIGHT NORTH TO EAST WINDS. HIGHS WILL BE AROUND
CLIMATOLOGICAL NORMAL INLAND FROM THE LAKE IN THE MID/UPPER 70S.
LONG TERM...
FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE MEDIUM.
THE UPPER LEVEL RIDGE WILL BE BREAKING DOWN INTO A MORE ZONAL FLOW
PATTERN OVER THE UPPER MIDWEST. A SHORTWAVE TRACKING ALONG THIS
RIDGE WILL MOVE ACROSS IA/IL LATE FRI NIGHT INTO SAT MORNING. A
CLUSTER OF THUNDERSTORMS/MCS SEEMS THE LIKELY MODE OF CONVECTION
WITH THIS FEATURE ON THE NOSE OF THE LOW LEVEL JET. SOUTHERN WI MAY
BE ON THE NORTHERN FRINGE OF THE STRONGER STORMS AND JUST GET THE
RAIN AND ELEVATED THUNDERSTORMS IF THE 00Z ECMWF MODEL SOLUTION PANS
OUT. THE GFS MODEL IS MAINTAINING A MORE NORTHERLY TRACK WHICH WOULD
IMPACT THE ENTIRE MKX FORECAST AREA WITH SHOWERS AND
STORMS...POSSIBLY STRONG.
ANOTHER ROUND OF SHOWERS AND STORMS WILL BE POSSIBLE SATURDAY NIGHT
WITH AN UPPER LEVEL SHORTWAVE TROUGH AND A WEAK SURFACE COLD
FRONT...BUT THIS HAS A PRETTY GOOD CHANCE OF REMAINING SOUTH OF THE
WI/IL BORDER.
SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM.
AN UPPER LEVEL TROUGH WILL SWING DOWN ACROSS THE GREAT LAKES REGION
SUNDAY AND MONDAY. THIS WILL BRING SHOWERS AND THUNDERSTORMS TO MUCH
OF WISCONSIN AHEAD OF AND ALONG A COLD FRONT. THE 00Z ECMWF IS ABOUT
12 HOURS SLOWER THAN THE GFS WITH THIS SYSTEM.
TUESDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE MEDIUM.
ONCE THAT SYSTEM CLEARS WISCONSIN...SURFACE HIGH PRESSURE WILL
SETTLE OVER THE GREAT LAKES REGION AS A RELATIVELY WEAK UPPER LEVEL
RIDGE BUILDS IN OVER THE CENTER OF THE COUNTRY. OVERALL THE WEATHER
WILL BE QUIET FOR SOUTHERN WI...BUT THERE WILL PROBABLY CONTINUE TO
BE A SLIGHT CHANCE FOR THUNDERSTORMS MENTIONED IN THE FORECAST. THIS
IS DUE TO POSSIBLE WEAK RIPPLES IN THE UPPER LEVEL NORTHWEST FLOW
PATTERN OUT AHEAD OF THAT UPPER RIDGE.
AVIATION/12Z TAFS/...
MAINLY VFR INITIALLY WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS.
SOME MVFR/IFR CIGS VISIBILITIES ARE POSSIBLE AS THE SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS BECOME MORE NUMEROUS THIS AFTERNOON.
SOME STORMS COULD BE SEVERE. AS A LOW MOVES ACROSS NORTHERN
ILLINOIS THIS AFTERNOON THE MVFR/IFR CIGS/VSBYS WILL BECOME MORE
NUMEROUS. THE THUNDERSTORM CHANCES WILL END TONIGHT BY MIDNIGHT AS
THE LOW MOVES ACROSS NORTHERN INDIANA.
MARINE...
SOME CONCERN OF FOG TODAY. WINDS WILL BE LIGHT OVER THE LAKE
AND THE PRESENT AIR MASS IS MOIST. GIVEN THE LIGHT WINDS THAT WILL
VEER FROM THE NORTH TO THE EAST NORTHEAST AND THE AFOREMENTIONED AIR
MASS...INCLUDED PATCHY DENSE FOG IN THE NEARSHORE ZONES. NOT ENOUGH
CONFIDENCE AT THIS TIME TO GO WITH A DENSE FOG ADVISORY. THEN
CONCERN IS INCREASING THUNDERSTORM CHANCES. SOME MAY BE SEVERE.
BRISK NORTH WINDS ON TONIGHT COULD REACH SMALL CRAFT CRITERIA.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...DDV
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
THURSDAY THROUGH TUESDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
641 AM CDT WED JUN 12 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 318 AM CDT WED JUN 12 2013
MAIN CONCERN FOR TODAY INTO THIS EARLY EVENING WILL BE SEVERE
THUNDERSTORM THREAT ACROSS THE SOUTH.
WATER VAPOR IMAGERY/RAP 500MB HEIGHT FIELD SHOWS A VIGOROUS
SHORTWAVE TROUGH MOVING OUT OF MT/WY INTO WESTERN ND/SD/NE. SURFACE
MAP AS OF 2 AM HAD AN AREA OF LOW PRESSURE ALONG THE KS/NE BORDER
WITH A WARM FRONT EXTENDING ENE ALONG I-80 IN IA AND IL. 850MB
MOISTURE TRANSPORT/ISENTROPIC LIFT AHEAD OF THE LOW AND OVER THE
WARM FRONT WAS PRODUCING SCATTERED ELEVATED SHRA/TS ACROSS OUR
FORECAST AREA...WITH A MORE INVIGORATED N-S LINE OF STORMS ACROSS
CENTRAL SD WHICH WAS HEADED EAST AROUND 50KT. RAP CORFIDI VECTORS
TAKE THIS COMPLEX OF STORMS DUE EAST AT 55-65KT THIS MORNING...WHICH
WOULD BRING IT INTO OUR AREA IN THE 7-9 AM TIME FRAME. MEANWHILE...A
NEW COMPLEX OF THUNDERSTORMS WERE FIRING ACROSS NORTHWEST
IA...MOVING TOWARD THE EAST. THIS CONVECTION WAS ROOTED A BIT CLOSER
TO THE CAPE POOL JUST NORTH OF THE 925-850MB WARM FRONT. A COUPLE
OBS IN SD WHERE THIS LINE PASSED RECORDED 43/48KT. HOWEVER...WRF
MODELS...NAMELY THE 12.00Z NSSL WRF WHICH SEEMS TO HAVE THE BEST
HANDLE ON THE CONVECTION RIGHT NOW...HAS THIS CONVECTION DECAYING AS
IT MOVES INTO THE AREA IN THE 5-8AM TIME FRAME. WITH 0-3KM BULK
SHEAR IN THE 40-50KT RANGE AND 0-3KM ML MUCAPE HOVERING IN THE
1000-2000J/KG...WILL HAVE TO WATCH THIS ONGOING CONVECTION CAREFULLY
FOR A SEVERE WIND THREAT EARLY THIS MORNING.
THERE THEN SEEMS TO BE A BREAK IN THE ACTION FROM MID-MORNING UNTIL
EARLY AFTERNOON BEFORE THE MID-LEVEL TROUGH AND SURFACE LOW MOVE
ACROSS EASTERN IA IN THE 18Z-21Z TIME FRAME. THIS TROUGH/STEEPENING
MID LEVEL LAPSE RATES THEN INTERACTS WITH 2000-3500J/KG 0-1KM ML
MUCAPE POOL IN PLACE SOUTH OF I-90 TO FIRE VIGOROUS/DEEP
CONVECTION. COOLING MID LEVEL/STEEPER LAPSE RATES AND 0-3KM BULK
SHEAR IN THE 20-40KT RANGE WILL SUPPORT A SEVERE HAIL/WIND THREAT
SOUTH OF I-90. AND...WITH THE JUXTAPOSITION OF THE LOW/WARM FRONT
PRODUCING FAVORABLE 0-3KM SRH...CANNOT RULE OUT A TORNADIC THREAT
ACROSS PORTIONS OF NORTHEAST IA INTO FAR SOUTHWEST WI...NAMELY
FAYETTE AND CLAYTON COUNTIES IN NORTHEAST IA AND GRANT COUNTY IN WI.
LOCALIZED FLOODING IS ALSO A CONCERN WITH THIS CONVECTION AS
PRECIPITABLE WATER VALUES HOVER IN THE 1.5 TO 2 INCH RANGE. SEE
HYDROLOGY SECTION BELOW FOR FURTHER DETAILS ON HEAVY RAIN POTENTIAL
AND IMPACTS. PLAN ON THE LOW AND ASSOCIATED CONVECTION TO MOVE
SOUTHEAST OF THE REGION AROUND MIDNIGHT TONIGHT. HIGH PRESSURE THEN
STARTS NOSING IN AFTER MIDNIGHT FROM THE NORTHERN PLAINS FOR
CLEARING SKIES.
HIGH PRESSURE WILL BE IN CONTROL ON THURSDAY WITH PLEASANT
TEMPERATURES IN THE 70S AND LOWER HUMIDITY LEVELS.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 318 AM CDT WED JUN 12 2013
HIGH PRESSURE REMAINS IN CONTROL ACROSS THE AREA THURSDAY NIGHT
THROUGH FRIDAY MORNING FOR A CONTINUED DRY RESPITE. BY FRIDAY
AFTERNOON THOUGH...A TROUGH OF LOW PRESSURE OVER THE PLAINS BEGINS TO
SHOVE MOISTURE BACK INTO THE AREA...MAINLY WEST OF THE MISSISSIPPI
RIVER FOR A CHANCE OF SHOWERS/ISOLATED THUNDER. FOR FRIDAY NIGHT
THROUGH SATURDAY EVENING...LOOK FOR LOW PRESSURE OVER CANADA TO SEND
A COLD FRONT THROUGH THE AREA. THIS WILL PRODUCE THE LIKELIHOOD OF
SHOWERS AND THUNDERSTORMS. WILL NEED TO WATCH FOR THE POSSIBILITY OF
SEVERE WEATHER GIVEN 0-1KM ML MUCAPE IN THE 1500-3500J/KG AND MODEST
AMOUNT OF 0-3KM BULK SHEAR. LINGERING MID-LEVEL TROUGH/FAIRLY STEEP
LAPSE RATES ENOUGH TO WARRANT A LOWER-END SHRA/TS CHANCE SUNDAY
THROUGH MONDAY. NORTHWEST FLOW AND ANOTHER WEAK MID-LEVEL TROUGH IN
THIS FLOW PRODUCE ANOTHER SHRA/TS CHANCE ON TUESDAY. OTHERWISE...
LOOKS LIKE TEMPERATURES WILL BE RIGHT AROUND NORMAL THROUGH THE
PERIOD...MAINLY IN THE 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 641 AM CDT WED JUN 12 2013
AN AREA OF LIGHT TO MODERATE RAINFALL IS MOVING ACROSS THE REGION
BUT SHOULD CLEAR BOTH RST AND LSE OVER THE NEXT FEW HOURS.
CONDITIONS ARE VFR UNTIL YOU GO FURTHER SOUTH WHERE A CLUSTER OF
THUNDERSTORMS IS TRACKING TO THE EAST ACROSS NORTHEAST IOWA.
MAINLY HIGH LEVEL CLOUD COVER TO CONTEND WITH BEHIND THIS SYSTEM
WITH VISIBILITY REMAINING VFR.
THUNDERSTORMS ARE EXPECTED TO REDEVELOP ACROSS THE REGION TOWARD
MID AFTERNOON AND TRACK TO THE SOUTH BY EARLY EVENING. VISIBILITY
WILL LIKELY DROP TO AT LEAST MVFR BUT COULD DROP TO IFR AT TIMES.
AFTER THE STORMS DROP TO THE SOUTHEAST BY THIS EVENING...EXPECT
THAT SKIES WILL CLEAR OUT AND WINDS WILL SHIFT AROUND TO THE
NORTHWEST.
&&
.HYDROLOGY...TODAY INTO THIS EVENING
ISSUED AT 318 AM CDT WED JUN 12 2013
FOR AREAS MAINLY ALONG AND SOUTH OF I-90...EXPECTING RAINFALL
AMOUNTS FROM TODAY INTO THIS EVENING IN THE 0.75 TO 1.25 INCH RANGE
WITH THE POSSIBILITY OF LOCALLY HIGHER AMOUNTS IN THUNDERSTORM
ACTIVITY. GIVEN THE WET SOILS IN PLACE...PLAN ON SOME RUNOFF ISSUES
WITH PONDING OF WATER AND SOME SIGNIFICANT WITHIN BANK RIVER RISES.
ANY LONGER DURATION/HIGHER RAINFALL RATES WOULD INCREASE THE
FLOODING POTENTIAL. STAY TUNED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...HALBACH
HYDROLOGY....DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
318 AM CDT WED JUN 12 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 318 AM CDT WED JUN 12 2013
MAIN CONCERN FOR TODAY INTO THIS EARLY EVENING WILL BE SEVERE
THUNDERSTORM THREAT ACROSS THE SOUTH.
WATER VAPOR IMAGERY/RAP 500MB HEIGHT FIELD SHOWS A VIGOROUS
SHORTWAVE TROUGH MOVING OUT OF MT/WY INTO WESTERN ND/SD/NE. SURFACE
MAP AS OF 2 AM HAD AN AREA OF LOW PRESSURE ALONG THE KS/NE BORDER
WITH A WARM FRONT EXTENDING ENE ALONG I-80 IN IA AND IL. 850MB
MOISTURE TRANSPORT/ISENTROPIC LIFT AHEAD OF THE LOW AND OVER THE
WARM FRONT WAS PRODUCING SCATTERED ELEVATED SHRA/TS ACROSS OUR
FORECAST AREA...WITH A MORE INVIGORATED N-S LINE OF STORMS ACROSS
CENTRAL SD WHICH WAS HEADED EAST AROUND 50KT. RAP CORFIDI VECTORS
TAKE THIS COMPLEX OF STORMS DUE EAST AT 55-65KT THIS MORNING...WHICH
WOULD BRING IT INTO OUR AREA IN THE 7-9 AM TIME FRAME. MEANWHILE...A
NEW COMPLEX OF THUNDERSTORMS WERE FIRING ACROSS NORTHWEST
IA...MOVING TOWARD THE EAST. THIS CONVECTION WAS ROOTED A BIT CLOSER
TO THE CAPE POOL JUST NORTH OF THE 925-850MB WARM FRONT. A COUPLE
OBS IN SD WHERE THIS LINE PASSED RECORDED 43/48KT. HOWEVER...WRF
MODELS...NAMELY THE 12.00Z NSSL WRF WHICH SEEMS TO HAVE THE BEST
HANDLE ON THE CONVECTION RIGHT NOW...HAS THIS CONVECTION DECAYING AS
IT MOVES INTO THE AREA IN THE 5-8AM TIME FRAME. WITH 0-3KM BULK
SHEAR IN THE 40-50KT RANGE AND 0-3KM ML MUCAPE HOVERING IN THE
1000-2000J/KG...WILL HAVE TO WATCH THIS ONGOING CONVECTION CAREFULLY
FOR A SEVERE WIND THREAT EARLY THIS MORNING.
THERE THEN SEEMS TO BE A BREAK IN THE ACTION FROM MID-MORNING UNTIL
EARLY AFTERNOON BEFORE THE MID-LEVEL TROUGH AND SURFACE LOW MOVE
ACROSS EASTERN IA IN THE 18Z-21Z TIME FRAME. THIS TROUGH/STEEPENING
MID LEVEL LAPSE RATES THEN INTERACTS WITH 2000-3500J/KG 0-1KM ML
MUCAPE POOL IN PLACE SOUTH OF I-90 TO FIRE VIGOROUS/DEEP
CONVECTION. COOLING MID LEVEL/STEEPER LAPSE RATES AND 0-3KM BULK
SHEAR IN THE 20-40KT RANGE WILL SUPPORT A SEVERE HAIL/WIND THREAT
SOUTH OF I-90. AND...WITH THE JUXTAPOSITION OF THE LOW/WARM FRONT
PRODUCING FAVORABLE 0-3KM SRH...CANNOT RULE OUT A TORNADIC THREAT
ACROSS PORTIONS OF NORTHEAST IA INTO FAR SOUTHWEST WI...NAMELY
FAYETTE AND CLAYTON COUNTIES IN NORTHEAST IA AND GRANT COUNTY IN WI.
LOCALIZED FLOODING IS ALSO A CONCERN WITH THIS CONVECTION AS
PRECIPITABLE WATER VALUES HOVER IN THE 1.5 TO 2 INCH RANGE. SEE
HYDROLOGY SECTION BELOW FOR FURTHER DETAILS ON HEAVY RAIN POTENTIAL
AND IMPACTS. PLAN ON THE LOW AND ASSOCIATED CONVECTION TO MOVE
SOUTHEAST OF THE REGION AROUND MIDNIGHT TONIGHT. HIGH PRESSURE THEN
STARTS NOSING IN AFTER MIDNIGHT FROM THE NORTHERN PLAINS FOR
CLEARING SKIES.
HIGH PRESSURE WILL BE IN CONTROL ON THURSDAY WITH PLEASANT
TEMPERATURES IN THE 70S AND LOWER HUMIDITY LEVELS.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 318 AM CDT WED JUN 12 2013
HIGH PRESSURE REMAINS IN CONTROL ACROSS THE AREA THURSDAY NIGHT
THROUGH FRIDAY MORNING FOR A CONTINUED DRY RESPITE. BY FRIDAY
AFTERNOON THOUGH...A TROUGH OF LOW PRESSURE OVER THE PLAINS BEGINS TO
SHOVE MOISTURE BACK INTO THE AREA...MAINLY WEST OF THE MISSISSIPPI
RIVER FOR A CHANCE OF SHOWERS/ISOLATED THUNDER. FOR FRIDAY NIGHT
THROUGH SATURDAY EVENING...LOOK FOR LOW PRESSURE OVER CANADA TO SEND
A COLD FRONT THROUGH THE AREA. THIS WILL PRODUCE THE LIKELIHOOD OF
SHOWERS AND THUNDERSTORMS. WILL NEED TO WATCH FOR THE POSSIBILITY OF
SEVERE WEATHER GIVEN 0-1KM ML MUCAPE IN THE 1500-3500J/KG AND MODEST
AMOUNT OF 0-3KM BULK SHEAR. LINGERING MID-LEVEL TROUGH/FAIRLY STEEP
LAPSE RATES ENOUGH TO WARRANT A LOWER-END SHRA/TS CHANCE SUNDAY
THROUGH MONDAY. NORTHWEST FLOW AND ANOTHER WEAK MID-LEVEL TROUGH IN
THIS FLOW PRODUCE ANOTHER SHRA/TS CHANCE ON TUESDAY. OTHERWISE...
LOOKS LIKE TEMPERATURES WILL BE RIGHT AROUND NORMAL THROUGH THE
PERIOD...MAINLY IN THE 70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT
1105 PM CDT TUE JUN 11 2013
BANDS OF SHRA/TS FIRING ALONG LINES OF CONVERGENCE...MOSTLY WELL
ELEVATED WITH CIGS 10 KFT. SOME CHANGES IN THE MESO MODELS WITH HOW
THEY HANDLE LARGE THUNDERSTORM COMPLEXES EXPECTED TO DEVELOP OVER
THE NEXT FEW HOURS. ENOUGH CONSENSUS THAT WILL LEAN THE TAFS TOWARD
THESE SOLUTIONS...WHICH NOW BRING AN AREA OF SHRA/TS UP FROM
NEB/WESTERN IA BY 09Z...EXITING BY 15Z OR SO. THERE STILL WILL BE A
THREAT FOR STRONGER STORMS CAPABLE OF ENHANCED GUSTS...BUT PROBABLY
NOT BASED ON AN ORGANIZED LINE OF STORMS WITH BOWING STRUCTURES.
THERE COULD BE A BREAK FOR THE LATE MORNING/EARLY AFTERNOON HOURS
BEFORE THE PCPN THREAT INCREASES BY 21Z. CONFIDENCE INCREASING
ENOUGH TO INCLUDE SHRA/TS MENTION FOR KRST/KLSE BY THIS TIME...BUT
WILL HANG ONTO SOME VCSH BETWEEN THE MORNING AND LATE AFTERNOON
CONVECTION. AGAIN...SOME THREAT FOR ENHANCED WIND GUSTS LATE
AFTERNOON...BUT NOT ENOUGH CONFIDENCE TO ADD A TEMPO GROUP FOR THIS
AS OF YET.
STORMS AND CLOUDS EXIT SHORTLY AFTER 00Z THU...WITH SKC/SCT VFR
CONDITIONS AND LIGHTER NORTHERLY WINDS THROUGH THE NIGHT TIME HOURS.
&&
.HYDROLOGY...TODAY INTO THIS EVENING
ISSUED AT 318 AM CDT WED JUN 12 2013
FOR AREAS MAINLY ALONG AND SOUTH OF I-90...EXPECTING RAINFALL
AMOUNTS FROM TODAY INTO THIS EVENING IN THE 0.75 TO 1.25 INCH RANGE
WITH THE POSSIBILITY OF LOCALLY HIGHER AMOUNTS IN THUNDERSTORM
ACTIVITY. GIVEN THE WET SOILS IN PLACE...PLAN ON SOME RUNOFF ISSUES
WITH PONDING OF WATER AND SOME SIGNIFICANT WITHIN BANK RIVER RISES.
ANY LONGER DURATION/HIGHER RAINFALL RATES WOULD INCREASE THE
FLOODING POTENTIAL. STAY TUNED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK
HYDROLOGY....DAS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
250 AM CDT WED JUN 12 2013
.SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH
ENTRANCE REGION OF 90 KNOT 250 MB JET MAX OVER THE GREAT LAKES IS
ACROSS CENTRAL/SOUTHERN WISCONSIN TODAY BEFORE AN UPPER LEVEL TROUGH
AXIS WITH A TRAILING 90 KNOT JET MAX PUSHES ACROSS NORTHERN ILLINOIS
TONIGHT.
MAINLY WEAK UPPER DIVERGENCE EARLY THIS MORNING BEFORE AN AREA OF
STRONG UPPER DIVERGENCE MOVES ACROSS SOUTHERN WISCONSIN LATER THIS
MORNING. HOWEVER THIS APPEARS TO HAVE SOME CONVECTIVE FEEDBACK FROM
THUNDERSTORMS OVER NORTHWEST IOWA THAT THE NAM PUSHES EAST ACROSS
WISCONSIN. THIS IS ALSO SEEN AS AN AREA OF CYCLONIC VORTICITY AT
500 MB AHEAD OF THE MAIN MID LEVEL SHORTWAVE THAT MOVES ACROSS
NORTHERN ILLINOIS/SOUTHERN WISCONSIN THIS AFTERNOON AND EVENING.
WHILE THE MAIN 700 MB THERMAL RIDGE MOVES ACROSS NORTHERN
ILLINOIS...SOUTHERN WISCONSIN WILL BE IN A MODERATE TEMPERATURE
GRADIENT. WEAK/MODERATE 700 MB UPWARD MOTION EXISTS ACROSS SOUTHERN
WISCONSIN WITH A STRONGER 15 MICROBAR/SEC AREA LATE THIS AFTERNOON
WITH THE MAIN MID LEVEL TROUGH. THE STRONGER 850 MB/700 MB WINDS
SET UP ACROSS NORTHERN ILLINOIS. WEAK TO MODERATE 850 MB MOISTURE
CONVERGENCE OCCURS OVER SOUTHERN WISCONSIN THROUGH THE MORNING WITH
A STRONGER AREA WITH THE SHORTWAVE THIS AFTERNOON.
PRECIPITABLE WATER VALUES REACH ALMOST 2 INCHES BY EARLY EVENING
OVER MUCH OF SOUTHERN WISCONSIN.
THE RAP AND MOST OF THE MESOSCALE MODELS BRING SCATTERED TO NUMEROUS
SHOWERS/THUNDERSTORMS THIS MORNING WITH THE MAIN MCS MOVING ACROSS
NORTHERN ILLINOIS AND PORTIONS OF SOUTHERN WISCONSIN LATER THIS
AFTERNOON. THIS APPEARS REASONABLE.
THE 04Z HRRR TRIES TO DEVELOP THE NORTHWEST IOWA MCS BUT WEAKENS IT
OVER SOUTHERN WISCONSIN THIS MORNING...AND TAKE THE SOUTH DAKOTA MCS
AND WEAKENS IT INTO A MORE WEST TO EAST AREA OF SHOWERS AND
THUNDERSTORMS.
WHAT MAY HAPPEN IS MORE OF A HEAVY RAIN EVENT WITH THE AFTERNOON MCS
FORMED BY THE SYNOPTIC SHORTWAVE AND ASSOCIATED SURFACE LOW. THE
SPC DAY ONE OUTLOOK HAS A MODERATE RISK JUST SOUTH OF THE WISCONSIN
BORDER WITH A SLIGHT RISK OVER SOUTHERN WISCONSIN. THIS AGREES WITH
THE NEW 00Z CIPS ANALOGS THAT PLACE THE MAJORITY OF THE 30 KNOT WIND
PROBABILITIES AND SEVERE REPORTS TO THE SOUTH OF WISCONSIN...WITH A
FEW WIND SEVERE WIND REPORTS IN FAR SOUTHERN WISCONSIN.
THE SHORTWAVE DROPS INTO NORTHERN INDIANA AFTER MIDNIGHT TONIGHT.
EXPECT A SURGE OF NORTH WINDS ESPECIALLY DOWN LAKE MICHIGAN LATE
THIS EVENING AND TONIGHT.
THURSDAY THROUGH FRIDAY...FORECAST CONFIDENCE HIGH.
A HIGH PRESSURE RIDGE WILL BE MOVING ACROSS THE UPPER MIDWEST AND
GREAT LAKES REGION DURING THIS PERIOD. EXPECT SUNSHINE...LOWER
DEWPOINTS AND LIGHT NORTH TO EAST WINDS. HIGHS WILL BE AROUND
CLIMATOLOGICAL NORMAL INLAND FROM THE LAKE IN THE MID/UPPER 70S.
.LONG TERM...
FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE MEDIUM.
THE UPPER LEVEL RIDGE WILL BE BREAKING DOWN INTO A MORE ZONAL FLOW
PATTERN OVER THE UPPER MIDWEST. A SHORTWAVE TRACKING ALONG THIS
RIDGE WILL MOVE ACROSS IA/IL LATE FRI NIGHT INTO SAT MORNING. A
CLUSTER OF THUNDERSTORMS/MCS SEEMS THE LIKELY MODE OF CONVECTION
WITH THIS FEATURE ON THE NOSE OF THE LOW LEVEL JET. SOUTHERN WI MAY
BE ON THE NORTHERN FRINGE OF THE STRONGER STORMS AND JUST GET THE
RAIN AND ELEVATED THUNDERSTORMS IF THE 00Z ECMWF MODEL SOLUTION PANS
OUT. THE GFS MODEL IS MAINTAINING A MORE NORTHERLY TRACK WHICH WOULD
IMPACT THE ENTIRE MKX FORECAST AREA WITH SHOWERS AND
STORMS...POSSIBLY STRONG.
ANOTHER ROUND OF SHOWERS AND STORMS WILL BE POSSIBLE SATURDAY NIGHT
WITH AN UPPER LEVEL SHORTWAVE TROUGH AND A WEAK SURFACE COLD
FRONT...BUT THIS HAS A PRETTY GOOD CHANCE OF REMAINING SOUTH OF THE
WI/IL BORDER.
SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM.
AN UPPER LEVEL TROUGH WILL SWING DOWN ACROSS THE GREAT LAKES REGION
SUNDAY AND MONDAY. THIS WILL BRING SHOWERS AND THUNDERSTORMS TO MUCH
OF WISCONSIN AHEAD OF AND ALONG A COLD FRONT. THE 00Z ECMWF IS ABOUT
12 HOURS SLOWER THAN THE GFS WITH THIS SYSTEM.
TUESDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE MEDIUM.
ONCE THAT SYSTEM CLEARS WISCONSIN...SURFACE HIGH PRESSURE WILL
SETTLE OVER THE GREAT LAKES REGION AS A RELATIVELY WEAK UPPER LEVEL
RIDGE BUILDS IN OVER THE CENTER OF THE COUNTRY. OVERALL THE WEATHER
WILL BE QUIET FOR SOUTHERN WI...BUT THERE WILL PROBABLY CONTINUE TO
BE A SLIGHT CHANCE FOR THUNDERSTORMS MENTIONED IN THE FORECAST. THIS
IS DUE TO POSSIBLE WEAK RIPPLES IN THE UPPER LEVEL NORTHWEST FLOW
PATTERN OUT AHEAD OF THAT UPPER RIDGE.
&&
.AVIATION/12Z TAFS/...
MAINLY VFR INITIALLY WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS.
SOME MVFR/IFR CIGS VISIBILITIES ARE POSSIBLE AS THE SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS BECOME MORE NUMEROUS THIS AFTERNOON.
SOME STORMS COULD BE SEVERE. AS A LOW MOVES ACROSS NORTHERN
ILLINOIS THIS AFTERNOON THE MVFR/IFR CIGS/VSBYS WILL BECOME MORE
NUMEROUS. THE THUNDERSTORM CHANCES WILL END TONIGHT BY MIDNIGHT AS
THE LOW MOVES ACROSS NORTHERN INDIANA.
&&
.MARINE...
SOME CONCERN OF FOG TODAY. WINDS WILL BE LIGHT OVER THE LAKE
AND THE PRESENT AIR MASS IS MOIST. GIVEN THE LIGHT WINDS THAT WILL
VEER FROM THE NORTH TO THE EAST NORTHEAST AND THE AFOREMENTIONED AIR
MASS...INCLUDED PATCHY DENSE FOG IN THE NEARSHORE ZONES. NOT ENOUGH
CONFIDENCE AT THIS TIME TO GO WITH A DENSE FOG ADVISORY. THEN
CONCERN IS INCREASING THUNDERSTORM CHANCES. SOME MAY BE SEVERE.
BRISK NORTH WINDS ON TONIGHT COULD REACH SMALL CRAFT CRITERIA.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
THURSDAY THROUGH TUESDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1105 PM CDT TUE JUN 11 2013
.UPDATE...
ISSUED AT 1105 PM CDT TUE JUN 11 2013
LINES OF CONVECTION DEVELOPING ALONG REGIONS OF CONVERGENCE...MOSTLY
ELEVATED WITH CLOUD BASES AT 10 KFT. DON/T EXPECT A SEVERE THREAT
WITH THESE.
STRONG/SEVERE STORMS STILL LOOK POSSIBLE OVERNIGHT...BUT TAKING A
DIFFERENT SHAPE TO PREVIOUS THINKING. LATEST MESO MODELS LEANING
TOWARD DEVELOPING AN AREA OF SHOWERS/STORMS OVER EASTERN
NEB...TRACKING THIS INTO NORTHEAST IA/SOUTHEAST MN BETWEEN 09-12Z.
THIS IS FUELED BY AN UPPER AIR DISTURBANCE...LOW LEVEL MOISTURE
TRANSPORT AND SOME LINGERING INSTABILITY. SOME STRONG TO POSSIBLY
DAMAGING WIND GUSTS ARE STILL POSSIBLE...WITH DRY SUB CLOUD LAYERS
ALSO FAVORING A WIND THREAT. SOMETHING TO WATCH...BUT FEEL THIS
MIGHT BE MORE OF AN ISOLATED THREAT RATHER THAN WIDESPREAD.
MEANWHILE...A DAMAGING LINE OF BOWING SEGMENTS STILL
POSSIBLE/LIKELY OVER THE NORTHERN PLAINS...BUT WITH THE EXPECTED
COMPLEX OUT AHEAD OF IT...USING UP THE INSTABILITY AND TAPPING THE
LOW LEVEL MOISTURE RETURN...IT PROBABLY WON/T HAVE THE FUEL TO MAKE
IT TO THE FORECAST AREA...LET ALONE WESTERN MN. THAT SAID...THE MCV
WITH THAT SYSTEM COULD BE A PLAYER IN OUR LOCAL WEATHER LATER WED
AFTERNOON. LATEST NAM12 SUGGESTS THAT THIS MCV WILL SPIN ACROSS THE
FORECAST AREA BY LATE AFTERNOON...SPARKING MORE SHOWERS AND STORMS.
THE ATMOSPHERE COULD DESTABILIZE ENOUGH BY THAT TIME THAT SOME
STRONG/SEVERE STORMS WILL AGAIN BECOME A THREAT. LOTS OF IFS WITH
THIS THOUGH...AND THE EVOLUTION OF LATER TONIGHT/WED MORNING WILL
HAVE A LARGE BEARING IN WHAT WE CAN EXPECTED FOR LATER WED.
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 345 PM CDT TUE JUN 11 2013
AT 3 PM...SCATTERED SHOWERS CONTINUED TO BE FOUND FROM THE
EASTERN DAKOTAS SOUTHEAST INTO NORTHEAST ILLINOIS AND SOUTHEAST
WISCONSIN. THESE SHOWERS ARE DEVELOPING ABOVE THE CAP DUE TO WEAK
TO MODERATE 700 TO 300 MB MOISTURE TRANSPORT...WEAK TO MODERATE
310 TO 320K ISENTROPIC UPGLIDE...WEAK TO MODERATE 700 TO 500 MB
FRONTOGENESIS...AND THE RIGHT ENTRANCE REGION OF A 100 KNOT
250 MB JET.
THE 11.12Z MODELS THAT THE 700 MB SHORT WAVE TROUGH OVER THE
CENTRAL DAKOTAS WILL MOVE ACROSS WEST-CENTRAL AND SOUTHWEST `
MINNESOTA LATE THIS AFTERNOON...AND THROUGH OUR AREA FROM LATE
EVENING INTO THE EARLY OVERNIGHT. THE 700 MB VAD WIND AT KABR JUST
RECENTLY WENT FROM WEST TO SOUTHWEST. AHEAD OF THIS WAVE...THE
MODELS CONTINUE TO SHOW THAT THE 700 TO 500 MB FRONTOGENESIS...
700 TO 300 MB MOISTURE TRANSPORT...AND 310 TO 320K ISENTROPIC LIFT
WILL INCREASES ACROSS THE FORECAST AREA. THE HRRR SUGGESTS THAT
SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD ALONG THE
FRONTOGENETIC WING AHEAD OF THIS WAVE BETWEEN 7 PM AND 10 PM IN
SOUTHEAST MINNESOTA...AND THEN SPREADS EAST INTO WESTERN
WISCONSIN MAINLY ALONG THE INTERSTATES OF 90 AND 94 BETWEEN 10 PM
AND 1 AM. AS THE SHORT WAVE MOVES INTO THE AREA EXPECT THE SHOWERS
AND THUNDERSTORMS TO SPREAD INTO NORTHEAST IOWA AND SOUTHWEST
WISCONSIN BETWEEN 11 PM AND 3 AM.
AFTER THIS SYSTEM MOVES THROUGH THE AREA...EXPECT A BREAK AND THEN
LOOKING FOR A MESOSCALE CONVECTIVE COMPLEX /LIKELY TO DEVELOP NEAR
RAPID CITY/ TO MOVE THROUGH THE AREA ON TUESDAY MORNING. THE
MODELS HAVE BEEN REALLY STRUGGLING WITH THE TIMING AND EVOLUTION OF
THIS SYSTEM. A FEW OF THE MESO MODELS HAVE SHOWED THAT A LINE OF
STORMS WOULD MOVE THROUGH THE AREA BETWEEN 5 AM AND 10 AM. 0-3 KM
SHEAR AND THE 700 TO 500 MB LAPSE RATES SUGGEST THAT THERE MAY BE
SOME DAMAGING WINDS ASSOCIATED WITH THIS LINE. MEANWHILE THE
ECMWF AND LATEST HRRR SUGGEST THAT THIS LINE MAY ARRIVE A BIT
LATER AND THAT THE LINE WILL NOT BE THAT STRONG WHEN IT MOVES
THROUGH THE AREA. BY FAR...THE ECMWF IS SLOWEST WITH THIS
SYSTEM...AND BY THE TIME THAT IT ARRIVES THERE IS NOT MUCH
INSTABILITY LEFT. AS A RESULT...THE SEVERE WEATHER THREAT IS STILL
UNCLEAR WITH THIS SYSTEM.
ANOTHER THING THAT WILL HAVE TO BE WATCHED TONIGHT IS THE THREAT
FOR HEAVY RAIN. BOTH THE GFS AND NAM/WRF SHOW THAT THE
PRECIPITABLE WATER VALUES WILL BE INCREASING UP TO 1.8 INCHES AND
THAT THE WARM CLOUD LAYER DEPTHS WILL BE INCREASING INTO THE 4 TO
4.5 KM RANGE. AS A RESULT...EXPECT THE SHOWERS AND THUNDERSTORMS
TO BECOME EFFICIENT RAIN PRODUCERS. WILL ESPECIALLY HAVE TO WATCH
FOR THE POTENTIAL OF TRAINING ALONG THE FRONTOGENETIC BAND.
RAINFALL AMOUNTS FROM 0.75 TO 1.50 INCHES LOOK POSSIBLE FROM
TONIGHT INTO WEDNESDAY MORNING. THERE MAY BE EVEN A FEW SPOTS THAT
COULD SEE UP TO 2 INCHES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 345 PM CDT TUE JUN 11 2013
ON WEDNESDAY EVENING...THE MOISTURE TRANSPORT QUICKLY MOVES WELL
EAST OF THE AREA AS THE UPPER LEVEL LOW MOVES AWAY FROM THE
REGION. THIS IS BIT FASTER THAN ORIGINALLY EXPECTED...SO LOWERED
THE PRECIPITATION CHANCES DURING THE EVENING AND TOOK THEM OUT FOR
THE OVERNIGHT.
FROM FRIDAY NIGHT INTO THE WEEKEND...THE MODELS CONTINUE TO SHOW
THAT SEVERAL MESOSCALE CONVECTIVE COMPLEXES WILL DEVELOP OVER THE
NORTHERN PLAINS AND THEN MOVE THROUGH THE FORECAST AREA. WHILE
THIS HAS BEEN A CONSISTENT SIGNAL...THE MODELS HAVE BEEN REALLY
STRUGGLE WITH BOTH THEIR LOCATION AND TIMING. AT THIS TIME...THE
MOST CONSISTENT SIGNAL IS FOR FRIDAY NIGHT INTO SATURDAY
MORNING...SO WENT THE HIGHEST PRECIPITATION DURING THIS TIME FRAME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1105 PM CDT TUE JUN 11 2013
BANDS OF SHRA/TS FIRING ALONG LINES OF CONVERGENCE...MOSTLY WELL
ELEVATED WITH CIGS 10 KFT. SOME CHANGES IN THE MESO MODELS WITH HOW
THEY HANDLE LARGE THUNDERSTORM COMPLEXES EXPECTED TO DEVELOP OVER
THE NEXT FEW HOURS. ENOUGH CONSENSUS THAT WILL LEAN THE TAFS TOWARD
THESE SOLUTIONS...WHICH NOW BRING AN AREA OF SHRA/TS UP FROM
NEB/WESTERN IA BY 09Z...EXITING BY 15Z OR SO. THERE STILL WILL BE A
THREAT FOR STRONGER STORMS CAPABLE OF ENHANCED GUSTS...BUT PROBABLY
NOT BASED ON AN ORGANIZED LINE OF STORMS WITH BOWING STRUCTURES.
THERE COULD BE A BREAK FOR THE LATE MORNING/EARLY AFTERNOON HOURS
BEFORE THE PCPN THREAT INCREASES BY 21Z. CONFIDENCE INCREASING
ENOUGH TO INCLUDE SHRA/TS MENTION FOR KRST/KLSE BY THIS TIME...BUT
WILL HANG ONTO SOME VCSH BETWEEN THE MORNING AND LATE AFTERNOON
CONVECTION. AGAIN...SOME THREAT FOR ENHANCED WIND GUSTS LATE
AFTERNOON...BUT NOT ENOUGH CONFIDENCE TO ADD A TEMPO GROUP FOR THIS
AS OF YET.
STORMS AND CLOUDS EXIT SHORTLY AFTER 00Z THU...WITH SKC/SCT VFR
CONDITIONS AND LIGHTER NORTHERLY WINDS THROUGH THE NIGHT TIME HOURS.
&&
.HYDROLOGY...TONIGHT INTO WEDNESDAY
ISSUED AT 345 PM CDT TUE JUN 11 2013
FOR AREAS MAINLY ALONG AND SOUTH OF INTERSTATE 94 CORRIDOR...PLAN
ON RAINFALL AMOUNTS FROM TONIGHT THROUGH WEDNESDAY TO RANGE FROM
0.75 TO 1.50 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE. WITH WET
SOILS IN PLACE...EXPECT SOME RUNOFF ISSUES AND SOME SIGNIFICANT
WITHIN BANK RIVER RISES TO OCCUR. WILL HAVE TO KEEP A CLOSE EYE
ON ANY AREAS THAT MAY SEE LONGER DURATION/HIGHER RAINFALL RATES
FOR FLOODING POTENTIAL. STAY TUNED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE.......RIECK
SHORT TERM...BOYNE
LONG TERM....BOYNE
AVIATION.....RIECK
HYDROLOGY....BOYNE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
401 AM MDT WED JUN 12 2013
.SHORT TERM...(TODAY AND THURSDAY)
ISSUED AT 223 AM MDT WED JUN 12 2013
CURRENT WATERVAPOR SATELLITE LOOP SHOWS THE POTENT
SHORTWAVE DISTURBANCE ALOFT...WHICH AIDED IN SEVERE TSTORM
DEVELOPMENT ACROSS THE DAKOTAS AND WESTERN NEBRASKA LAST
NIGHT...PUSHING EASTWARD INTO THE NORTHERN PLAINS AS A SHORT WAVE
RIDGE MOVES INTO THE FORECAST AREA BEHIND THE DISTURBANCE. DRIER
AIR HAS MOVED INTO SOUTHEAST WYOMING AND THE SOUTHERN NEBRASKA
PANHANDLE EARLY THIS MORNING...WHICH SHOULD GREATLY LIMIT DAYTIME
CONVECTION WITH ADDITIONAL MIDLEVEL SUBSIDENCE. HOWEVER...MODELS
SHOW ANOTHER SHORTWAVE MOVING ACROSS THE HIGH PLAINS LATER TODAY
AS A WEAK SURFACE TROUGH/MOISTURE GRADIENT DEVELOPS ALONG THE
LARAMIE RANGE. ALTHOUGH LLVL INSTABILITY IS MARGINAL...KEPT A
SLIGHT CHANCE OF SHOWERS AND TSTORMS ALONG AND JUST EAST OF THE
LARAMIE RANGE TODAY WHERE EAST TO SOUTHEAST WINDS WILL DEVELOP AND
BECOME BREEZY BY LATE THIS AFTERNOON. SOUTHWEST WINDS ARE EXPECTED
WEST OF THE LARAMIE RANGE...AND MAY GUST TO 30-35 MPH AT TIMES.
PATCHY FOG IS POSSIBLE ACROSS MOST OF THE WESTERN NEBRASKA
PANHANDLE TONIGHT AND EARLY THURSDAY MORNING. OTHERWISE...THERE IS
A BETTER CHANCE OF THUNDERSTORMS ON THURSDAY AS THE UPPER LEVEL
FLOW BACKS INTO THE SOUTHWEST AHEAD OF A PACIFIC STORM SYSTEM
PUSHING INTO THE PACIFIC NORTHWEST. THE LLVL CONVERGENCE
BOUNDARY/MOISTURE GRADIENT WILL REMAIN NEAR THE LARAMIE RANGE
DURING THE DAY...WITH PW/S INCREASING OVER 1.00 INCHES ACROSS
WESTERN NEBRASKA. MODELS SHOW MUCH MORE LLVL INSTABILITY...WITH
LI/S AS LOW AS -9C ACROSS NEBRASKA AND CAPE VALUES BETWEEN 2500 TO
3500 J/KG. A FEW STRONG THUNDERSTORMS ARE POSSIBLE THURSDAY
AFTERNOON AS WELL. TEMPERATURES WILL REMAIN ABOVE NORMAL...WITH
VERY LITTLE CHANGE IN HIGH TEMPERATURES WHICH RANGE FROM THE MID
TO UPPER 80S ACROSS SOUTHEAST WYOMING TO THE LOW 90S ACROSS
WESTERN NEBRASKA AND THE NORTH PLATTE RIVER VALLEY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 401 AM MDT WED JUN 12 2013
WEATHER PATTERN WILL BE RELATIVELY PERSISTENT THROUGH EARLY NEXT
WEEK WITH AN UPPER LEVEL TROUGH OVER THE NW CONUS AND A RIDGE INTO
THE CENTRAL CONUS. RIDGE WILL FLATTEN OUT EARLY THIS WEEKEND AS
UPPER LEVEL WAVE MOVES OUT OF THE PACIFIC NW AND INTO SOUTH
CENTRAL CANADA BUT THE RIDGE WILL REBOUND BY EARLY NEXT WEEK.
STARTING OFF THURSDAY EVENING THERE WILL BE A SMALL CHANCE FOR
THUNDERSTORMS. COULD SEE AN ISOLATED SHOWER OR THUNDERSTORM OVER
THE MOUNTAINS BUT THE MAIN CONCERN WILL BE ALONG THE EASTERN
FRINGES OF THE FORECAST AREA IN THE NEBRASKA PANHANDLE. COULD SEE
A FEW SEVERE THUNDERSTORMS BUT AT THIS TIME THE GREATEST
INSTABILITY SHOULD BE EAST OF THE FORECAST AREA.
FRIDAY LOOKS WARM AND DRY WITH WILL MINIMAL THUNDERSTORM CHANCES.
MODELS SHOWING A WEAK SHORTWAVE SLIDING JUST SOUTH AND EAST OF THE
AREA WITH A STRONGER WAVE NORTH ACROSS MONTANA. AS LONG AS THE
PLACEMENT OF THESE FEATURES IS CORRECT THEN MOST OF THE AREA WILL
STAY DRY.
FRONTAL BOUNDARY WILL BRING A SHOT OF COOLER AIR FRIDAY NIGHT.
HIGH TEMPERATURES SATURDAY SHOULD BE A GOOD 5 TO 10 DEGREES COOLER
THAN FRIDAY...MAINLY IN THE 80S WITH SOME 70S WEST. TEMPERATURES
WILL SLOWLY REBOUND SUNDAY THROUGH EARLY NEXT WEEK AS THE UPPER
RIDGE BUILDS BACK INTO THE ROCKIES. CHANCES FOR THUNDERSTORMS
WILL MAINLY FOCUS EAST OF THE LARAMIE RANGE...MAINLY LATE
AFTERNOON AND EVENING. IT IS A BIT EARLY TO SAY...BUT GIVEN MODEL
PROJECTIONS FOR INSTABILITY AND SHEAR...SEVERE THUNDERSTORMS LOOK
TO BE GOOD POSSIBILITY SHOULD STORMS DEVELOP.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING)
ISSUED AT 1029 PM MDT TUE JUN 11 2013
CONVECTION HAS MOVED OFF TO THE EAST THIS EVENING. STILL A CHANCE
OF STRATUS OUT IN THE PANHANDLE TONIGHT...BUT HRRR NOT REALLY
GOING WIDESPREAD WITH ITS FORECAST. WENT AHEAD WITH LOW MVFR IN
THE KAIA AND KCDR TAFS TONIGHT AROUND 10Z THROUGH 15Z. LOOKS
REALLY DRY WEDNESDAY. THE ONLY AREA THAT COULD SEE CONVECTION
TOMORROW WOULD BE THE NORTHERN PANHANDLE.
&&
.FIRE WEATHER...
ISSUED AT 223 AM MDT WED JUN 12 2013
FIRE WEATHER CONCERNS WILL CONTINUE TO BE MINIMAL INTO THIS
WEEKEND MAINLY DUE TO GREEN FUELS. A RIDGE OF HIGH PRESSURE WILL
BUILD OVER THE AREA TODAY AND THURSDAY...WITH MOSTLY DRY
CONDITIONS AND VERY WARM TEMPERATURES CONTINUING. DAYTIME MIN
HUMIDITIES WILL REMAIN IN THE TEENS IN SOUTHEAST WYOMING...MAINLY
WEST OF THE LARAMIE RANGE...WITH 20 TO 40 PERCENT EXPECTED ACROSS
THE HIGH PLAINS INTO WESTERN NEBRASKA. WINDY CONDITIONS WILL
CONTINUE ALONG AND WEST OF THE LARAMIE RANGE THROUGH THIS TIME AS
WELL...WITH GUSTS OF 30 TO 40 MPH COMMON IN THE AFTERNOON EACH
DAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...TJT
LONG TERM...LIEBL
AVIATION...CLAYCOMB
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1033 PM MDT TUE JUN 11 2013
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 405 PM MDT TUE JUN 11 2013
RADAR AND VISIBLE SATELLITE TRENDS SHOW CONVECTION TRYING TO
DEVELOP ALONG THE LEESIDE PRESSURE TROUGH/DRYLINE WHICH IS NOW
POSITIONED FROM EASTERN CONVERSE COUNTY IN WYOMING DOWN TO THE
SOUTHEAST IN CENTRAL KIMBALL COUNTY IN NEBRASKA. LAPS AND SPC MESO
ANALYSIS OF MLCAPE BOTH SHOW THE CAP ERODING JUST TO THE EAST OF
THIS BOUNDARY WITH A STRONGER CAP FURTHER EAST INTO NEBRASKA. 50+
KTS OF DEEP LAYER SHEAR IS BEING ANALYZED OVER THIS AREA AS
WELL...WITH LLVL SHEAR ON THE WEAK SIDE. STILL EXPECTING
CONVECTION TO STRENGTHEN AND INCREASE IN COVERAGE THROUGH THE LATE
AFTERNOON JUST EAST OF THE DRYLINE WHERE 1000 TO 1500 J/KG MLCAPE
IS IN PLACE WITH A SLOWLY WEAKENING CAP. RECENT RAP AND HRRR MODEL
RUNS AGREE WITH THE IDEA OF WIDELY SCATTERED SHOWERS AND STORMS LATE
THIS AFTERNOON AND EARLY EVENING MOVING EAST-NORTHEAST AHEAD OF
THE DRYLINE WITH LLVL SHEAR INCREASING MAINLY ACROSS THE NORTHERN
AND EASTERN PANHANDLE. AS A RESULT...WILL NOT MAKE ANY CHANGES TO
THIS MORNINGS UPDATE FOR A FEW STORMS TO BECOME SEVERE THROUGH
THIS EVENING...WITH THE HIGHEST POTENTIAL FOR SEVERE IN THE NORTHERN
PANHANDLE COUNTIES.
FURTHER WEST...WEST TO SOUTHWEST WINDS WILL CONTINUE TO GUST 35 TO
50 MPH AS THE UPPER LEVEL WAVE MOVES OVERHEAD THIS AFTERNOON AND
PUSHES THE LEESIDE PRESSURE TROUGH TO THE EAST. WINDS WILL
DIMINISH TONIGHT BEHIND A WEAK COOL FRONT MOVING SOUTH ACROSS THE
EASTERN PLAINS AFTER MIDNIGHT. A VERY MOIST BOUNDARY LAYER BEHIND
THE FRONT...COMBINED WITH ANY OUTFLOW FROM THIS EVENINGS
THUNDERSTORMS...WILL PRODUCE PATCHY AREAS OF FOG MAINLY IN LOW
LYING AREAS OF THE NEBRASKA PANHANDLE LATE TONIGHT AS SFC WINDS
DIMINISH.
SFC WINDS WILL SHIFT TO THE NORTH BEHIND THE FRONT TONIGHT...THEN
SOUTHEAST THROUGH WEDNESDAY AFTERNOON ACROSS THE EASTERN PLAINS WITH
CONTINUED BREEZY SOUTHWEST WINDS WEST OF THE LARAMIE RANGE. THE
UPPER LEVEL RIDGE WILL REBUILD OVER THE FORECAST AREA WITH A WEAK
PIECE OF ENERGY MOVING UP FROM THE SOUTHWEST IN THE LATER AFTERNOON.
A FEW STORMS COULD FIRE OVER THE LARAMIE RANGE AS SFC WINDS TURN TO
THE SOUTHEAST...ALTHOUGH COOLER SFC TEMPS BEHIND THE FRONT WILL KEEP
CONDITIONS MORE STABLE ACROSS THE EASTERN PLAINS. DECREASING WINDS
AND A CONTINUED MOIST BOUNDARY LAYER WILL ONCE AGAIN PRODUCE PATCHY
FOG OVER THE PANHANDLE ON WEDNESDAY NIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT PM MDT TUE JUN 11 2013
THE 12Z MODEL SOLUTIONS ARE REASONABLY CONSISTENT SHOWING THE UPPER
RIDGE SLOWLY TRANSLATING EASTWARD ACROSS THE GREAT PLAINS THURSDAY
AND FRIDAY. MEANWHILE...A TROUGH AND UPPER LOW OVER THE PACIFIC
NORTHWEST PIVOT EAST TO NORTHEAST THROUGH THE NORTHERN ROCKIES AND
INTO SOUTHERN CANADA INTO THE WEEKEND. THIS WILL FLATTEN THE RIDGE
OVER THE FRONT RANGE. A RIDGE AXIS THEN REBUILDS ALONG THE FRONT
RANGE AND ADJACENT PLAINS EARLY NEXT WEEK.
THE MAIN SURFACE WEATHER FEATURE OF THE LONG TERM WILL BE A MEANDERING
DRY LINE/TROUGH SEPARATING MOIST UNSTABLE AIR TO THE EAST FROM MUCH
DRIER AIR TO THE WEST. THIS BOUNDARY WILL BE DRIFTING EAST FROM THE
EASTERN WYOMING PLAINS INTO THE WESTERN PANHANDLE THURSDAY AS A
PACIFIC FRONT MOVES THROUGH THE CWFA LATE THURSDAY NIGHT AND FRIDAY
MORNING. ISOLATED CONVECTION WILL DEVELOP DURING THE EARLY AFTERNOON
ALONG THE LARAMIE RANGE AND MOVE EAST ONTO THE PLAINS FROM MID
AFTERNOON INTO THE EVENING. THIS FRONTAL PASSAGE WILL SHIFT WINDS
TO WESTERLY WITH DRIER AIR INFILTRATING MUCH OF THE REGION. THE
FRONT WILL STALL OVER WESTERN NEBRASKA FRIDAY AFTERNOON. WEAK
INSTABILITY AND SOME LOW LEVEL MOISTURE NEAR THE FRONT MAY TRIGGER A
FEW TSTORMS OVER THE SOUTHERN PANHANDLE FRIDAY AFTERNOON AND EARLY
EVENING. THE SURFACE TROUGH DRIFTS WEST INTO FAR SOUTHEAST WYOMING
SATURDAY AFTERNOON. LOW LEVEL CONVERGENCE NEAR THE LARAMIE RANGE MAY
TRIGGER ISOLATED TSTORMS. OTHERWISE...IT WILL REMAIN DRY. THE DRY LINE
DRIFTS EAST INTO THE WESTERN PANHANDLE WITH ISOLATED DIURNAL CONVECTION
POSSIBLE. BOTH MONDAY AND TUESDAY WILL FEATURE ISOLATED AFTERNOON AND
EVENING CONVECTION ALONG AND EAST OF THE LARAMIE RANGE.
TEMPERATURES THROUGHOUT THE LONG TERM WILL AVERAGE ABOVE SEASONAL
NORMALS. THURSDAY WILL BE THE WARMEST DAY WITH HIGHS FROM 85 TO 95.
FRIDAY AND SATURDAY WILL TREND SLIGHTLY COOLER WITH THE PASSAGE OF
THE PACIFIC FRONT. TEMPERATURES WARM SOMEWHAT SUNDAY THROUGH TUESDAY
WITH THE INFLUENCE FROM THE UPPER RIDGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING)
ISSUED AT 1029 PM MDT TUE JUN 11 2013
CONVECTION HAS MOVED OFF TO THE EAST THIS EVENING. STILL A CHANCE
OF STRATUS OUT IN THE PANHANDLE TONIGHT...BUT HRRR NOT REALLY
GOING WIDESPREAD WITH ITS FORECAST. WENT AHEAD WITH LOW MVFR IN
THE KAIA AND KCDR TAFS TONIGHT AROUND 10Z THROUGH 15Z. LOOKS
REALLY DRY WEDNESDAY. THE ONLY AREA THAT COULD SEE CONVECTION
TOMORROW WOULD BE THE NORTHERN PANHANDLE.
&&
.FIRE WEATHER...
ISSUED AT 405 PM MDT TUE JUN 11 2013
A WEATHER DISTURBANCE MOVING TOWARD THE DISTRICT
TODAY WILL BRING A CHANCE FOR THUNDERSTORMS ACROSS THE
EASTCENTRAL PLAINS OF WYOMING AND THE NEBRASKA PANHANDLE THIS
AFTERNOON AND EVENING. STRONG WINDS...LIGHT TO MODERATE RAIN...AND
SOME HAIL WILL OCCUR WITH THESE THUNDERSTORMS.
GUSTY WEST TO SOUTHWEST WINDS AND DRY CONDITIONS WILL CONTINUE
THROUGH THIS EVENING ALONG AND WEST OF THE LARAMIE RANGE WHERE
HUMIDITIES HAVE DROPPED TO BETWEEN 6 AND 14 PERCENT AND WINDS ARE
GUSTING 35 TO 45 MPH THIS AFTERNOON. WINDS WILL EASE AND
HUMIDITIES WILL RECOVER TO BETWEEN 30 AND 50 PERCENT TONIGHT. A
RIDGE OF HIGH PRESSURE WILL BUILD OVER THE DISTRICT ON WEDNESDAY
AND THURSDAY...AND SO MOSTLY DRY AND WARM TEMPERATURES WILL
CONTINUE THROUGH THIS TIME. HUMIDITIES WILL REMAIN IN THE TEENS TO
LOW 20S IN SOUTHEAST WYOMING...WITH 20 TO 30 PERCENT EXPECTED IN
THE NEBRASKA PANHANDLE. WINDS WILL REMAIN ON THE WINDY SIDE ALONG
AND WEST OF THE LARAMIE RANGE THROUGH THIS TIME AS WELL...WITH
GUSTS OF 30 TO 40 MPH COMMON IN THE AFTERNOON EACH DAY. FURTHER
EAST...WINDS WILL BE OUT OF THE SOUTHEAST AND WILL GUST 20 TO 30
MPH IN THE AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RJM
LONG TERM...MAJ
AVIATION...CLAYCOMB
FIRE WEATHER...RJM
AREA FORECAST DISCUSSION...UPDATE FOR AVIATION
NWS LITTLE ROCK AR
1235 AM CDT FRI JUN 14 2013
.AVIATION...
OVERALL VFR FLIGHT CONDITIONS ARE EXPECTED OVER THE NEXT 24 HOURS. A
COLD FRONT WILL SLOWLY SAG SW OVERNIGHT AND BRING A BIT MORE DRIER
AIR TO AR. THIS SHOULD LIMIT ANY FOG FORMATION AROUND SUNRISE
FRIDAY. WINDS AHEAD OF THE FRONT WILL BE LIGHT FROM THE
SOUTH...WHILE BEHIND THE FRONT FROM THE NE AT 3 TO 8 KNOTS. (59)
&&
.PREV DISCUSSION... /ISSUED 817 PM CDT THU JUN 13 2013/
.UPDATE...
COLD FRONT CONTINUES TO WORK ITS WAY ACROSS THE STATE THIS EVENING
WITH THE BOUNDARY EASY TO SPOT ON WSR-88D IMAGERY. A FEW SHOWERS
HAVE DEVELOPED OVER SOUTHEAST ARKANSAS ALONG THE BOUNDARY BUT WITH
LOSS OF HEATING...NOT EXPECTING THESE TO REMAIN TOGETHER MUCH
LONGER. CURRENT PRECIPITATION GRIDS...AND ALL GRIDS FOR THAT
MATTER...REMAIN IN GOOD SHAPE AND NO CHANGES ARE NEEDED TONIGHT.
TEMPERATURES ACROSS THE BOUNDARY ARE SLIGHTLY COOLER BUT DEW POINT
TEMPERATURES ARE MUCH LOWER. DEW POINT AT THE WFO HAVE DROPPED 8
DEGREES IN THE PAST HOUR AFTER FROPA WITH THE DRIER AIR MOVING
SOUTH BEHIND THE BOUNDARY.
&&
PREV DISCUSSION... /ISSUED 245 PM CDT THU JUN 13 2013/
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
W-E ORIENTED CDFNT WAS SITUATED ACRS CNTRL AR AT MID AFTN. DEWPOINTS
IN THE LOWER AND MID 70S HAVE POOLED IN THE VCNTY OF THE BNDRY...
RESULTING IN HEAT INDICES BETWEEN 100 AND 105 DEGREES. HAVE SEEN A
FEW WEAK RADAR RETURNS OVR ERN AR. THE RUC AND HRRR MODELS CONT TO
INDCD ISOLD SHRA/TSRA DVLPG ALONG THE FNT OVR CNTRL/SERN AR LATE
THIS AFTN/EARLY EVENING. THUS...WL LEAVE SOME SMALL POPS IN PER
GOING FCST.
THE AFOREMENTIONED CDFNT WL EVENTUALLY STALL OUT TO THE SW OF THE
AREA BY FRI AS A WEAK SFC RDG BLDS INTO AR. THE BNDRY WL MEANDER IN
THE VCNTY OF WRN AR HEADING INTO THE WEEKEND. CANNOT RULE OF A STRAY
SHRA/TSRA FRI AND SAT ALONG WITH WRN PERIPHERY OF THE SFC RDG...BUT
WL KEEP A DRY FCST IN PLACE. E/NELY SFC WINDS BEHIND THE FNT WL
BRING DRIER AND SLIGHTLY COOLER AIRMASS TO MUCH OF THE FA.
THE SFC HIGH WL WEAKEN ENOUGH BY SUN/SUN NGT FOR A RETURN OF SLY
WINDS...ALONG WITH INCRSG LOW LVL RH. MEANWHILE...THE UPR LVL FLOW
WL FLATTEN TO ALLOW A NEW CDFNT WL APCH AR FM THE N...ALONG WITH A
BETTER CHC OF SHRA/TSRA. THE UNSETTLED PATTERN WL CONT INTO THE LONG
TERM PD.
LONG TERM...MONDAY THROUGH THURSDAY
UPPER RIDGE WILL BE PUSHED SOUTH OF THE STATE FOR THE BEGINNING OF
NEXT WEEK...AND ALLOW A COLD FRONT TO MOVE INTO THE STATE. MODELS
ARE IN BETTER AGREEMENT OF MOVING THIS FRONT FURTHER INTO THE STATE
THAN PREVIOUS RUNS...AND HAVE INCREASED POPS TO THE CHANCE CATEGORY
FOR MONDAY INTO TUESDAY. UPPER RIDGE WILL BEGIN TO BUILD BACK OVER
THE AREA WEDNESDAY INTO THURSDAY...WITH RAIN CHANCES DWINDLING.
TEMPERATURES WILL CONTINUE TO BE ABOVE NORMAL ACROSS THE SOUTH...
WHILE NORTHERN ARKANSAS WILL HAVE A LITTLE COOLER TEMPERATURES DUE
TO CLOUD COVER AND RAINFALL.
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
340 AM CDT FRI JUN 14 2013
.DISCUSSION...
...MAIN FORECAST CONCERN IS CONVECTION THIS MORNING...THEN AGAIN
THIS AFTERNOON AND TONIGHT...
LATEST WATER VAPOR IMAGERY AND RAP 500MB ANALYSIS SHOW A TROUGH AXIS
EXTENDING FROM LOW PRESSURE IN ALBERTA SOUTHWARD TOWARD NORTHERN
NEVADA. DOWNSTREAM...A HIGH PRESSURE RIDGE AXIS EXTENDS FROM THE
SOUTHERN PLAINS INTO CENTRAL MANITOBA. AN EMBEDDED WEAK SHORTWAVE
CONTINUES TO MOVE UP THE BACKSIDE OF THE RIDGE AND INTO CENTRAL
NEBRASKA. WIDELY SCATTERED THUNDERSTORMS CONTINUE IN ADVANCE OF
THIS SHORTWAVE AND THESE ARE SLOWLY MOVING EAST-NORTHEAST. MOST
LIKELY SCENARIO TO PLAY OUT SEEMS TO BE WHAT THE HRRR AND RAP
HAVE BEEN INDICATING AND THAT IS FOR THE CONVECTION ASSOCIATED
WITH THE ABOVE MENTIONED SHORTWAVE TO CONTINUE TO CLUSTER TOGETHER AND
DRIFT EAST ACROSS THE CWA THROUGH THE MORNING WHERE STRONG
ISENTROPIC UPGLIDE RESIDES. SOME OF THESE MAY CONTAIN MARGINALLY
SEVERE HAIL...AIDED BY A VEERED 35-45KT LOW LEVEL JET.
CLOUD COVER FROM MORNING CONVECTIVE ACTIVITY WILL LIKELY INHIBIT
STRONG HEATING INITIALLY. AS HIGH PLAINS SFC LOW PRESSURE SLIDES
EAST TODAY...A WARM FRONT WILL EXTEND WEST TO EAST ACROSS THE
FORECAST AREA BRINGING A RAPID WARM UP TO THE AREA THIS
AFTERNOON...ESPECIALLY IN OUR SOUTH. IN ADDITION...SFC DEWPOINTS
ARE PROGGED TO RISE INTO THE LOWER 70S BY AFTERNOON WHICH MAY BE A
BIT HIGH AND PUSHES FORECASTED SFC BASED CAPE VALUES INTO THE 4000
J/KG RANGE. WITH AN INCREASING SOUTHWEST LOW LEVEL JET EARLY IN
THE EVENING AIDING TSTMS...THINK BUSIEST TIMEFRAME IN TERMS OF ANY
SEVERE STORMS WILL BE FROM ABOUT 23Z-03Z NEAR THE SFC BOUNDARY.
THIS WILL MOST LIKELY LINGER INTO THE OVERNIGHT HOURS AS A
POSSIBLE MCS AS THE BOUNDARY REMAINS IN THE AREA. ALL THIS LIMITED
OF COURSE BY CAPPING INVERSION...ESPECIALLY THIS AFTERNOON.
WILL CONTINUE TO CARRY POPS THROUGH THE WEEKEND AS THE BOUNDARY
REMAINS OVER THE AREA ALTHOUGH DO NOT THINK WE WILL HAVE A
CONTINUOUS PERIOD OF THUNDERSTORMS THROUGHOUT THE ENTIRE WEEKEND.
WITH WESTERLY MID LEVEL FLOW...HIGHER POPS ARE WARRANTED WITH
THIS BOUNDARY EXTENDING OVER THE AREA.
NO CHANGES INTO THE LATER PERIODS WITH DRIER WEATHER ON TAP FOR
MONDAY AND TUESDAY AND A BIT MORE ACTIVE MID TO LATE WEEK.
KERN
&&
.AVIATION...06Z TAFS FOR KOMA...KLNK...KOFK.
VFR CONDITIONS SHOULD OCCUR AT ALL THREE SITES OVERNIGHT. SOME
SHRA AND TSRA ARE EXPECTED TO DEVELOP OVER PARTS OF EASTERN
NEBRASKA BETWEEN ABOUT 10Z AND 12Z THEN AFFECT MAINLY KOFK AND
KOMA IN THE MORNING. CEILINGS WITH THIS ACTIVITY WOULD BE MAINLY
ABOVE 4000 FEET...BUT SOME MVFR CEILINGS AROUND 2500 FEET ARE
POSSIBLE. SOUTHERLY WINDS WILL INCREASE AND BECOME GUSTY BY MID
TO LATE MORNING.
TSRA SHOULD INCREASE OVER THE REGION MID TO LATE AFTN. INCLUDED A
PROB 30 GROUP FOR THIS AT KOFK...BUT LEFT OUT FOR KOMA AND KLNK
AT HIS TIME DUE TO UNCERTAINTY OF COVERAGE.
MILLER
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1150 PM CDT THU JUN 13 2013
.AVIATION...
06Z TAFS FOR KOMA...KLNK...KOFK.
VFR CONDITIONS SHOULD OCCUR AT ALL THREE SITES OVERNIGHT. SOME
SHRA AND TSRA ARE EXPECTED TO DEVELOP OVER PARTS OF EASTERN
NEBRASKA BETWEEN ABOUT 10Z AND 12Z THEN AFFECT MAINLY KOFK AND
KOMA IN THE MORNING. CEILINGS WITH THIS ACTIVITY WOULD BE MAINLY
ABOVE 4000 FEET...BUT SOME MVFR CEILINGS AROUND 2500 FEET ARE
POSSIBLE. SOUTHERLY WINDS WILL INCREASE AND BECOME GUSTY BY MID
TO LATE MORNING.
TSRA SHOULD INCREASE OVER THE REGION MID TO LATE AFTN. INCLUDED A
PROB 30 GROUP FOR THIS AT KOFK...BUT LEFT OUT FOR KOMA AND KLNK
AT HIS TIME DUE TO UNCERTAINTY OF COVERAGE.
MILLER
&&
.PREV DISCUSSION... /ISSUED 920 PM CDT THU JUN 13 2013/
UPDATE...
BAND OF PCPN THAT WAS MOVING THROUGH THE AREA THIS AFTERNOON AND
EARLY EVENING HAS MOVED EAST OF THE FORECAST AREA AS OF 9 PM SO
CLEANED UP ZFP WORDING FOR THAT. EXPECT THAT PCPN WILL PROBABLY
HOLD OFF MOST AREAS OVERNIGHT...BUT SOME CHANCE BY 3-4 AM CDT.
01Z HIGH RESOLUTION RAP AND 00Z NAM INDICATE THIS TREND. MADE A
FEW MINOR CHANGES TO POPS IN THE MORNING. OTHERWISE FEW IF ANY
CHANGES MADE BEYOND THE TONIGHT PERIOD.
MILLER
PREV DISCUSSION... /ISSUED 308 PM CDT THU JUN 13 2013/
DISCUSSION...
THUNDERSTORM COMPLEX...INITIALLY PROBABLY ROOTED NEAR 600 MB PER
LBF/OAX 12Z SOUNDINGS...CONTINUED WORKING INTO FORECAST AREA THIS
AFTERNOON DESPITE LACK OF LOW LEVEL JET/INSTABILITY SUPPORT. THIS
HIGHLIGHTS UNCERTAINTIES THAT WILL EXIST IN FINE-TUNING
THUNDERSTORM CHCS AND TIMES THROUGH THIS WEEKEND AND IS THE
PRIMARY FORECAST CONCERN.
CURRENT RADAR TRENDS/LATEST RAP FCST WOULD TAKE THIS AREA OF
CONVECTION OUT OF ERN ZONES BY AROUND 02Z WITH A PROBABLE PRECIP
LULL UNTIL CONVECTION DEVELOPING TO OUR WEST APPROACHES OR
DEVELOPS INTO ZONES LATER TONIGHT. MADE SOME ATTEMPTS AT
ADJUSTING HOURLY GRIDS TO REFLECT THIS TREND TONIGHT.
HOWEVER...AFTER THAT RELUCTANT TO REMOVE OR LOWER TOMORROW MORNING
POPS VERY MUCH...ESPECIALLY CNTRL/NE ZONES AS 00Z/12Z ECMWF AND
12Z GFS CONTINUED TO DEVELOP QPF OVER THE NERN FA IN 12-18Z PD.
SINCE THIS AREA WILL BE ON NOSE OF THE MOISTURE/INSTABILITY RETURN
NOTED BY STRONG H85 THETA E ADVECTION IN 12Z-15Z PERIOD PER
NAM...LEFT IN LIKELY MORNING POPS NERN ZONES. ALTHOUGH THERE COULD
BE A MIDDAY LULL IN THE ACTIVITY...THIS THETA ADVECTION INCREASES
AGAIN IN THE AFTERNOON. THUS CANNOT REALLY SAY WHETHER OR NOT
CONVECTION WILL COMPLETELY DIE OUT...WHICH HAS BEEN THE CASE TODAY
AND WAS A FEW DAYS AGO AS WELL. SFC BASED DWPT RETURN PER NAM/GFS
PROBABLY TOO HIGH THUS SFC BASED CAPE FORECAST ALSO TOO HIGH
FRIDAY...BUT WITH BOUNDARY IN AREA AND UPPER WAVE LIFTING INTO
NERN MT...SOME SEVERE THREAT WILL PROBABLY EXIST. HOWEVER...
COVERAGE PROBABLY DICTATED BY EFFECTIVENESS OF CAP WHICH WILL BE
TRYING TO BECOME ESTABLISHED...ESPECIALLY SRN ZONES...OR DEBRIS
CLOUDS/PCPN FROM ANY MORNING ACTIVITY NE. AT THIS TIME MADE
LITTLE/NO CHANCES TO MAX TEMPS WHICH WILL LIKELY NEED ADJUSTING AS
AMOUNT OF DEBRIS BECOMES APPARENT.
WITH BOUNDARY REMAINING OVER AREA SATURDAY AND POSSIBLY SUNDAY...
AND CNTRL PLAINS CONTINUING ON SRN END OF WESTERLIES OF SRN
CANADIAN LOW...MODESTLY HIGH POPS WARRANTED INTO SUNDAY. ALTHOUGH
AGAIN WOULD GENERALLY THINK CENTROID OF MCS ACTIVITY ON SYNOPTIC
SCALE COULD SHIFT SOUTH EACH DAY THUS HIGHER CHCS WOULD APPEAR TO
SHIFT INTO SRN ZONES BY SUNDAY/SUNDAY NIGHT. WITH ERLY FLOW
SETTING UP SATURDAY BEHIND EXPECTED MCS TOMORROW NIGHT...LEANED
TOWARD COOLER NAM FOR MAX TEMPS. NO CHANGES TO SUNDAY MAX TEMPS AT
THIS TIME.
DRIER WEATHER STILL ON TAP MONDAY AND PROBABLY TUESDAY AS WELL AS
NWRLY FLOW SENDS HIGH PRESSURE THROUGH ERN PLAINS AND FORECAST WAS
MOSTLY DRY. AFTER THAT...RETURNING MOISTURE WILL BRING INCREASING
TSTM RISK THRU END OF WEEK ALTHOUGH FOR THE TIME BEING KEPT MOST
POPS IN LOWER CHC RANGE.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
348 AM CDT FRI JUN 14 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 347 AM CDT FRI JUN 14 2013
MAIN CONCERN FOR THE SHORT TERM IS HOW MUCH CONVECTION WE GET
TODAY AND IF ANY WILL BE SEVERE.
THE MAIN UPPER TROUGH IS STILL OUT OVER WA/OR/ID BUT WV LOOP SHOWS
SOME LEAD SHORTWAVES SETTING OFF ACTIVITY OVER THE NORTHERN
ROCKIES. THE UPPER RIDGE AXIS CURRENTLY OVER THE RED RIVER VALLEY
WILL MOVE EAST INTO MN TODAY. THERE HAS BEEN SHOWERS AND STORMS
DEVELOPING OVER THE SOUTHEASTERN COUNTIES AS WELL AS JUST OUTSIDE
OUR NORTHWEST ALONG THE FRONT EDGE OF THE 850MB WARM AIR ADVECTION
AND RIGHT EXIT REGION OF THE LOW LEVEL JET. NONE OF THE MODELS
EXCEPT FOR THE RAP HAS HAD A GOOD HANDLE ON THE ACTIVITY. THINK
THAT THIS BAND OF LIGHT CONVECTION WILL SLOWLY SPREAD EASTWARD
DURING THE MORNING HOURS. WILL MAKE LAST MINUTE ADJUSTMENTS TO
POPS/WX BASED ON RADAR TRENDS.
BY LATE THIS AFTERNOON AND EVENING...THE MAIN SHORTWAVE WILL
APPROACH AND WILL HELP PUSH THE SFC TROUGH AXIS INTO THE RED RIVER
VALLEY. THINK THAT THERE WILL BE PLENTY OF LIFT TO WORK WITH...THE
QUESTION IS HOW MUCH INSTABILITY WILL BE AVAILABLE FOR CONVECTION.
THE MODELS HAVE DECENT 1000-2000 J/KG ALONG THE SFC TROUGH AXIS
THIS AFTERNOON...BUT THERE IS ALSO QUITE A BIT OF A CAP WITH 700MB
TEMPS IN THE LOW TEENS C. THERE IS ALSO THE QUESTION OF HOW MUCH
CLOUD COVER WILL BE HANGING AROUND FROM THIS MORNINGS ACTIVITY.
THERE CONTINUES TO BE QUITE A BIT OF PRECIP BREAKING OUT ALONG THE
SFC TROUGH ACCORDING TO THE MODELS. WILL CONTINUE TO KEEP FAIRLY
HIGH POPS AND WILL MENTION THE POSSIBILITY OF SOME HAIL AND WINDS
IN THE HWO...BUT WILL KEEP A MENTION OUT OF THE GRIDS FOR NOW.
THE UPPER TROUGH WILL MOVE INTO CENTRAL CANADA AND THE NORTHERN
PLAINS TONIGHT...WITH THE SFC TROUGH AXIS/WEAK FRONTAL BOUNDARY
PUSHING THE REST OF THE WAY THROUGH THE CWA. DECENT WINDS WILL
HELP KEEP LOWS IN THE 50S. NEAR ZONAL FLOW SETS UP OVER ND FOR
SATURDAY WITH THE MAIN SFC LOW WELL TO OUR NORTH OVER MANT/SASK.
WEST WINDS WILL REMAIN OVER THE PLAINS...AND WITH THE BEST COLD
AIR ADVECTION HOLDING OFF FOR NOW...HIGHS ON SATURDAY SHOULD AGAIN
CLIMB INTO THE MID TO UPPER 70S.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 347 AM CDT FRI JUN 14 2013
FOR THE REST OF THE WEEKEND...ANOTHER UPPER TROUGH WILL BEGIN TO
DIG DOWN OUT OF CANADA BY SUNDAY...PUSHING A MUCH MORE SIGNIFICANT
COLD FRONT DOWN INTO THE CWA. THERE COULD BE SOME SHOWERS AND
THUNDERSTORMS ALONG AND BEHIND THE FRONT...SO CONTINUED WITH
CHANCE POPS MAINLY ALONG THE INTERNATIONAL BORDER SUNDAY. PRECIP
WILL MOVE OFF TO THE SOUTH AND EAST SUNDAY NIGHT AS THE COLD FRONT
PUSHES THE REST OF THE WAY THROUGH THE CWA. HIGHS ON SUNDAY WILL
DEPEND ON EXACT TIMING OF THE FRONT...BUT FOR NOW HAVE HIGHS
AROUND 70 IN THE NORTHWEST AND NEAR 80 IN THE SOUTHEAST.
MODELS IN FAIR AGREEMENT WITH THE BEGINNING OF THE NEXT WORK WEEK. A
COOL MONDAY WILL SEE A CHC FOR SOME SHOWER ACTIVITY WITH COLD CORE
ALOFT ALLOWING LOW CONVECTIVE TEMPS TO BE REACHED IF ANY SFC SOLAR
OCCURS. SFC HIGH WITH 500MB RIDGING WILL GIVE OVERALL DRY AND WARM
WEATHER TUESDAY AND WEDNESDAY BEFORE THE NEXT SYSTEM MOVES INTO THE
REGION THURSDAY BRINGING THE NEXT CHC OF RAIN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY EVENING)
ISSUED AT 1159 PM CDT THU JUN 13 2013
EXPECT GENLY FAIR SKIES AND LIGHT EAST TO SOUTHEAST BLAYER FLOW
THROUGH THE LATE EVENING AND OVERNIGHT PERIODS. INCREASING MID TO
UPPER LEVEL CLOUDS EARLY ON FRIDAY. ISOLD TSMS IN FAR SERN ND
DURING THE OVERNIGHT. AREAS OF MVFR CIGS AND VSBYS IN TSTMS
EXPECTED ACROSS ERN ND FROM LATE FORENOON INTO FRIDAY AFTERNOON...
SPREADING INTO WRN MN THROUGH MID AND LATE AFTERNOON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...JR
LONG TERM...JR/JK
AVIATION...GUST
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1217 AM CDT FRI JUN 14 2013
.UPDATE...
ISSUED AT 919 PM CDT THU JUN 13 2013
MAIN CHANGE TO FORECAST INVOLVES PRECIPITATION CHANCES. FOR THIS
EVENING...DO EXPECT LIGHT SHOWERS/THUNDERSTORMS TO PERSIST IN NW
IA UNTIL ABOUT MID NIGHT. THIS IS ASSOCIATED WITH A WEAK 700 MB
FRONT.
FARTHER WEST...AM GOING TO DELAY CONVECTIVE CHANCES WEST OF I29
UNTIL AFTER 06Z AND REALLY NOT GO ABOVE A 20 PERCENT UNTIL AFTER
09Z. THE UPPER LEVEL WAVE IS WELL TO THE WEST YET AND AS A RESULT
THE STEEPER LAPSE RATES DO NOT ARRIVE INTO THE JAMES VALLEY UNTIL
06Z. OF EVEN GREATER CONCERN THE LOW LEVEL JET DOES NOT REALLY
INCREASE UNTIL AFTER 06Z. AS A RESULTS THE BEST THETA-E ADVECTION
IS NOT UNTIL ALMOST 12Z. BOTH RAP AND HRRR ARE MUCH SLOWER IN
DEVELOPING CONVECTION. IN FACT THE RAP HAS ALMOST NO CONVECTION
UNTIL AFTER 12Z. THAT MAY BE A LITTLE TOO SLOW GIVEN MUCAPES OF
1000 TO 1500 J/KG AND CIN NEAR ZERO AT KFSD BY 12Z AND APPROACHING
WEAK WAVE. CURRENT MENTION OF NICKEL TO HALF-DOLLAR SIZE HAIL IN
HWO FOR LATE TONIGHT AND TOMORROW SEEMS REASONABLE GIVEN AMOUNT OF
CAPE AVAILABLE TO STORMS...EVEN WITH EFFECTIVE SHEAR AROUND 20 KTS
FOR MORNING CONVECTION. TEMPERATURES LOOK ON TRACK FOR TONIGHT.
GRIDS UPDATED AND WILL UPDATE HWO SHORTLY TO SLOW DOWN TIMING OF
CONVECTION.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 405 PM CDT THU JUN 13 2013
ISOLATED SHOWERS AND THUNDERSTORMS THIS AFTERNOON WILL PASS OVER THE
AREA FROM SIOUX CITY TO STORM LAKE AND SOUTH WITH LITTLE FANFARE.
LATER TONIGHT IN AXIS OF INCREASING MOISTURE AND
INSTABILITY...ISOLATED STORMS ARE EXPECTED TO DEVELOP OVER MORE OF
THE AREA AND MOVE FROM WEST TO EAST...PROBABLY BECOMING SCATTERED BY
DAYBREAK IN THE EAST. AIR STILL DOES NOT LOOK UNSTABLE ENOUGH GIVEN
AVAILABLE MOISTURE AND MEAGER LIFT TO PRODUCE SEVERE WEATHER...BUT
SOME LATE COULD PUT DOWN SOME SMALL HAIL. THIS ACTIVITY WILL BE ONLY
SLOWLY INCREASING AS IT MOVES EAST INTO BETTER AREA OF THERMAL LIFT.
HOWEVER...INSTEAD OF DECREASING FRIDAY MORNING AS NOCTURNAL ACTIVITY
OFTEN DOES...EXPECT A CONTINUED SLOW INCREASE IN COVERAGE BECAUSE OF
INCREASING DYNAMIC SUPPORT AS WAVE AND SURFACE BOUNDARY APPROACH.
NIGHTTIME ACTIVITY HAS LITTLE SUPPORT FROM LOW LEVEL JET WHICH
DEVELOPS STRONGLY TO THE WEST OF OUR AREA...BUT EVEN THOUGH EXPECTED
TO DECREASE FRIDAY...IT WILL THEN BE MOVING INTO OUR AREA...SO
EXPECT SCATTERED ELEVATED STORMS TO CONTINUE DEVELOPING AT A TIME
WHEN THEY WOULD NORMALLY BE DECREASING. THE QUESTION REMAINS AT WHAT
TIME LATE IN THE DAY THE STORMS COULD BECOME MORE SURFACE BASED OR
WHETHER THEY EVEN WILL. HOWEVER...INSTABILITY SEEMS ENOUGH BY MIDDAY
FRIDAY FOR EVEN THESE ELEVATED STORMS TO PRODUCE ISOLATED SEVERE
HAIL REPORTS. TEMPERATURES TONIGHT AND FRIDAY WILL BE KEPT CLOSE TO
WHAT WE HAVE BEEN GOING FOR...A LITTLE COOLER THAN GUIDANCE IN THE
EAST DUE TO THE EXPECTED CLOUD COVER AND SCATTERED CONVECTION. WINDS
WILL INCREASE TO BREEZY LEVELS IN THE EAST FOR A WHILE FRIDAY AHEAD
OF SURFACE TROUGH/OCCLUDED FRONT.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 405 PM CDT THU JUN 13 2013
QUESTION FOR FRIDAY EVENING INTO THE OVERNIGHT IS WHETHER SURFACE
BASED CONVECTION FIRES ALONG THE APPROACHING FRONT...AND IF IT
DOES...WHEN AND WHERE. ELEVATED ACTIVITY ONGOING ACROSS OUR EAST
DURING THE AFTERNOON WILL LIKELY HINDER SURFACE HEATING SOMEWHAT.
ALSO A STRONG CAP IS FORECAST TO BE IN PLACE...ALTHOUGH THIS SHOULD
GRADUALLY BE ERODED AS COOLER MID LEVEL TEMPERATURES MOVE INTO THE
AREA. BEST UPPER FORCING WITH THE MAIN WAVE WILL STAY WELL TO OUR
NORTH. MEANWHILE BEST FRONTOGENETICAL FORCING LOOKS TO BE FOCUSED
ACROSS CENTRAL NEBRASKA. GIVEN THIS...COMBINED WITH UNCERTAINTY ON
HOW MUCH HEATING WE GET DURING THE DAY...SEEMS LIKE MOST LIKELY
SOLUTION HAS ONE AREA OF SHOWERS AND STORMS FORM NORTH OF OUR CWA
WITH THE BETTER UPPER LEVEL FORCING. AND ANOTHER AREA FORM IN SOUTH
CENTRAL NEBRASKA ALONG THE STRONGER PORTION OF THE
BOUNDARY...LEAVING OUR CWA IN THE MIDDLE. SUBTLE SIGNS THAT A
SECONDARY WAVE MAY EJECT OUT OF THE COLORADO ROCKIES DURING THE
AFTERNOON...WHICH MAY AID IN THE NEBRASKA DEVELOPMENT. EXPECT THIS
ACTIVITY TO THEN POTENTIALLY INCREASE NORTHEAST ALONG THE FRONT...AS
THE SECONDARY WAVE EJECTS EAST AND CAPPING WEAKENS DUE TO HEATING
AND COOLING ALOFT. QUESTION IS HOW FAR NORTH THIS CONVECTION GETS.
INDIVIDUAL STORM MOTION WILL TEND TO BE ALMOST DUE EASTERLY...THUS
THE BEST CHANCE WILL PROBABLY END UP ACROSS NORTHWEST IOWA AND
EXTREME SOUTHEAST SOUTH DAKOTA IN THE EVENING INTO THE OVERNIGHT.
STORMS WOULD INITIALLY BE SUPERCELLS BEFORE PROBABLY BECOMING MORE OF
A CLUSTER...WITH LARGE HAIL AND STRONG WINDS THE MAIN THREAT...BUT
GIVEN LOW LEVEL WIND FIELDS AN ISOLATED TORNADO WOULD ALSO BE
POSSIBLE IF STORMS GET INTO OUR AREA EARLY ENOUGH. FURTHER NORTH THE
THREAT SEEMS LOWER. HOWEVER WILL HAVE TO KEEP AN EYE ON THINGS...AS
IF AN ISOLATED STORM IS ABLE TO FORM ALONG THE FRONT NEAR THE JAMES
RIVER...IT WOULD LIKELY BECOME SUPERCELLUAR WITH CAPE AROUND 2000
J/KG AND DEEP LAYER SHEAR OF 40 OR MORE KTS.
SATURDAY SEES THE FRONT LIKELY TO OUR SOUTH. BUT DECENT UPPER
SUPPORT IN THE RIGHT ENTRANCE OF A STRONG UPPER JET IS EXPECTED.
MODELS ALSO SUGGEST THAT LOW TO MODERATE INSTABILITY MAY LINGER
ALONG AND SOUTH OF INTERSTATE 90. THUS WHILE IT WOULD SEEM LIKELY
THAT THE GREATEST THUNDERSTORM COVERAGE WILL REMAIN SOUTH IN THE
VICINITY OF THE FRONT...CAN NOT RULE OT ISOLATED TO SCATTERED
ACTIVITY SOUTH OF INTERSTATE 90. AGAIN SHEAR PROFILES WOULD SUPPORT A
LARGE HAIL AND WIND THREAT WITH ANY STORM THAT DOES FORM. HIGHS
DEPENDENT ON CLOUD COVER AND COVERAGE OF SHOWERS AND STORMS...BUT
NEAR SEASONABLE READINGS IN THE UPPER 70S TO LOW 80S SEEM PROBABLE.
ON SUNDAY A STRONGER WAVE WILL EJECT SOUTHEAST OUT OF CANADA AND
INTO THE FAR NORTHERN PLAINS. STILL UNCERTAINTY ON AVAILABLE
MOISTURE AND WHERE THE BEST FORCING ENDS UP. WIND FIELDS WOULD
SUGGEST A SEVERE THREAT WITH ANY STORMS THAT COULD FORM...BUT AGAIN
LATEST INDICATIONS ARE THAT THE BEST THREAT MAY END UP SOUTH OF US.
BUT SOMETHING TO KEEP AN EYE ON. HIGHS PROBABLY A COUPLE DEGREES
WARMER ON SUNDAY...BUT STILL AROUND OR JUST SLIGHTLY ABOVE AVERAGE.
DRIER AND COOLER AIR MOVES IN ON MONDAY BEHIND THE WAVE. MODELS
COMING IN A BIT COOLER ALOFT...AND THUS HIGHS LOOK LIKE THEY WILL
END UP AT LEAST A FEW DEGREES BELOW SEASONABLE NORMALS...WITH MID TO
UPPER 70S EXPECTED. RIDGING THEN BEGINS TO BUILD IN TUESDAY INTO
THURSDAY. ALTHOUGH LATEST RUNS SLOW THIS DOWN A BIT...SUGGESTING
SLIGHTLY COOLER HIGHS POSSIBLE. EITHER WAY EXPECTING READINGS
AROUND AVERAGE THROUGH THURSDAY...WITH A SLOW WARMING TREND EACH
DAY. RIDGE AXIS SHOULD MOVE OVERHEAD AROUND WEDNESDAY. UNCERTAINTY
ON TIMING AND PLACEMENT OF SUBTLE WAVES RIDING OVER THE RIDGE...BUT
THE SETUP WOULD SUGGEST AT LEAST THE MENTION OF A RETURN OF ISOLATED
SHOWERS AND THUNDERSTORMS ANYTIME LATER WEDNESDAY INTO THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1210 AM CDT FRI JUN 14 2013
GENERAL VFR CONDITIONS THROUGH THE TAF PERIOD. EXCEPTIONS WILL BE
IN BRIEF REDUCED VISIBILITIES IN CONVECTION WHICH MAY DEVELOP
ACROSS PORTIONS OF THE AREA IN THE MORNING HOURS OF FRIDAY...THEN
AGAIN IN THE AFTERNOON. SOUTHERLY WINDS WILL PICK UP BY LATE
MORNING AND CONTINUE INTO THE AFTERNOON.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...SCHUMACHER
SHORT TERM...
LONG TERM...CHENARD
AVIATION...JM
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
1159 PM CDT THU JUN 13 2013
.DISCUSSION...
SEE AVIATION SECTION.
&&
.AVIATION...
CHALLENGING AVIATION FORECAST WITH THE 00Z MODELS SHOWING A
WETTER PATTERN FOR WEST CENTRAL TEXAS. GIVEN HOW MOIST THE
AIRMASS IS BECOMING...ALONG WITH THE FORECAST TRACK OF THE UPPER
LOW AND EXTENT OF CONVECTIVE ACTIVITY ACROSS OUR AREA EARLIER IN
THE EVENING...A WETTER SOLUTION APPEARS MORE REASONABLE. WITH THIS
IN MIND...INTRODUCING VCSH AND LOWER CEILINGS SOONER IN THE DAY AT
KSOA...KJCT... KSJT AND KBBD. WITH UNCERTAINTY IN HOW EXTENSIVE
THE SHOWERS/THUNDERSTORM COVERAGE WILL BE...ALONG WITH HOW LOW THE
CEILINGS AND VISIBILITIES WILL BE WITH THE CONVECTION... KEEPING
THE CEILINGS VFR WITH THE 06Z TAF PACKAGE. CEILING AND VISIBILITY
REDUCTIONS INTO THE MVFR CATEGORY WILL BE POSSIBLE IN THE LOCALLY
HEAVY RAIN WHICH ACCOMPANIES THE CONVECTION. LOCALLY GUSTY WINDS
WILL ALSO BE POSSIBLE IN AND NEAR THUNDERSTORMS. SOUTH TO
SOUTHEAST WINDS ARE EXPECTED THROUGH THE TAF PERIOD.
19
&&
.PREV DISCUSSION... /ISSUED 1024 PM CDT THU JUN 13 2013/
UPDATE...
ADJUSTED POPS AND TEMPERATURES FOR THE REMAINDER OF THE NIGHT.
DISCUSSION...
CONVECTION HAS ALL BUT ENDED ACROSS THE AREA WITH ONLY SOME LIGHT
SHOWERS REMAINING ACROSS CROCKETT COUNTY. UPPER LOW CURRENTLY NEAR
THE BIG BEND WILL LIFT SLOWLY NORTH ACROSS THE TRANS PECOS REGION
THROUGH FRIDAY MORNING. LATEST NAM AND HRRR SHOW SOME ADDITIONAL
CONVECTION LIFTING NORTH ACROSS SOUTHWEST COUNTIES TOWARDS
DAYBREAK SO WILL KEEP INHERITED SLIGHT CHANCE TO LOW END CHANCE
POPS GOING ROUGHLY SOUTH AND WEST OF A SAN ANGELO TO JUNCTION LINE
FOR THE REMAINDER OF THE NIGHT. OVERNIGHT LOW TEMPERATURES WERE
ALSO RAISED A FEW DEGREES BASED ON TRENDS AND EXPECTED CLOUD
COVER.
PREV DISCUSSION... /ISSUED 655 PM CDT THU JUN 13 2013/
DISCUSSION...
SEE AVIATION SECTION.
AVIATION...
SCATTERED SHOWERS AND THUNDERSTORMS OVER CENTRAL AND SOUTHERN PARTS
OF WEST CENTRAL TEXAS ARE MOVING TO THE NORTHWEST...AND WILL POTENTIALLY
AFFECT THE KSJT AND KBBD TAF SITES DURING THE FIRST HOUR IN THE TAF
PERIOD /00-01Z/. GUSTY WINDS 35-40 KT ARE POSSIBLE IN AND NEAR THE
STORMS...AND A FEW OF THE STORMS WILL LIKELY CONTAIN FREQUENT
LIGHTNING. BRIEF REDUCTIONS IN CLOUD CEILING AND VISIBILITY ARE
POSSIBLE IN THE LOCALLY HEAVY RAIN WHICH ACCOMPANIES THIS
CONVECTION. THE SHOWERS AND STORMS WILL GRADUALLY DISSIPATE LATE
THIS EVENING. CLOUD COVER WILL DECREASE DURING THE NIGHT WITH VFR
CONDITIONS EXPECTED TO PREVAIL. LATE NIGHT INCREASE IN BOUNDARY
LAYER MOISTURE LOOKS MARGINAL FOR LOW CLOUD DEVELOPMENT ACROSS OUR
SOUTHERN COUNTIES. HOLDING OFF WITH A LOW CLOUD MENTION FOR NOW
AND WILL REVISIT THIS WITH THE NEXT /06Z/ TAF PACKAGE. A VFR-BASED
CUMULUS FIELD IS EXPECTED TO DEVELOP DURING THE DAY THURSDAY.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP PRIMARILY
DURING THE AFTERNOON... WITH THE BETTER COVERAGE ANTICIPATED
ACROSS ROUGHLY WEST OF A SWEETWATER TO SAN ANGELO TO SONORA LINE.
SOME OF THE SHOWERS MAY DEVELOP BY MID-TO-LATE MORNING THURSDAY
ACROSS THE SOUTHWESTERN PART OF WEST CENTRAL TEXAS /SOUTHWEST OF A
MERTZON TO SONORA LINE/. AT THIS TIME...CARRYING VCSH FOR ALL AREA
TAF SITES EXCEPT KABI FOR THURSDAY AFTERNOON. MAY ADJUST THE
TIMING WITH THE NEXT TAF PACKAGE. SIMILAR TO TODAY...WILL HAVE A
POSSIBILITY OF GUSTY WINDS...FREQUENT LIGHTNING...AND BRIEF CLOUD
CEILING AND VISIBILITY REDUCTIONS IN THE LOCALLY HEAVY RAINFALL
WHICH ACCOMPANIES SOME OF THE STORMS.
19
PREV DISCUSSION... /ISSUED 605 PM CDT THU JUN 13 2013/
UPDATE...
WIDLEY SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH
MID EVENING SOUTH OF THE BIG COUNTRY. POPS WERE ADDED ACROSS
EASTERN PORTIONS OF THE CONCHO VALLEY...HEARTLAND AND NORTHWEST
HILL COUNTRY THROUGH MID EVENING. SEVERE WEATHER IS NOT EXPECTED
BUT STORMS WILL BE CAPABLE OF BRIEF HEAVY RAINFALL...WIND GUSTS TO
45 MPH AND DANGEROUS CLOUD TO GROUND LIGHTNING. NO OTHER CHANGES
MADE AT THIS TIME.
PREV DISCUSSION... /ISSUED 331 PM CDT THU JUN 13 2013/
SHORT TERM...
/TONIGHT THROUGH FRIDAY/
AN UPPER LOW IS SITUATED OVER THE BIG BEND REGION EARLY THIS
AFTERNOON AT THE BASE OF AN UPPER RIDGE THAT EXTENDS NORTH THROUGH
THE PLAINS STATES. PER LATEST RADAR...A LARGE AREA OF ASSOCIATED
SHOWERS AND THUNDERSTORMS EXTENDS FROM THE BIG BEND COUNTRY EAST
TO THE TEXAS GULF COAST. THIS AREA OF SHOWERS IS SLOWLY MAKING ITS
WAY NORTH AND SHOULD ENTER OUR SOUTHERN TIER OF COUNTIES LATER
THIS AFTERNOON. THE CENTER OF THE UPPER LOW IS FORECAST TO MOVE
NORTH ON A TRACK JUST WEST OF THE FORECAST AREA TO A POSITION OVER
THE NORTHERN PANHANDLE BY LATE TOMORROW. THE BULK OF SHOWERS
ASSOCIATED WITH THIS SYSTEM WILL REMAIN WEST OF THE CWA WITH THE
BEST CHANCE OF RAINFALL FOR OUR AREA BEING THE SOUTHWESTERN CWA
THROUGH TONIGHT AND THROUGH THE DAY TOMORROW...WITH POPS
DECREASING FROM SOUTHWEST TO NORTHEAST. AFTERNOON HIGHS TOMORROW
WILL REFLECT THE EXPECTED CLOUD COVER AND RAINFALL WITH MID 80S
OVER THE SOUTHWESTERN CWA TO THE MID 90S OVER THE NORTHEASTERN
CWA...WHICH SHOULD BE RAIN FREE WITH LESS CLOUD COVER. LOOKING FOR
MORNING LOWS TOMORROW IN THE LOWER 70S ACROSS ALL OF THE FORECAST
AREA.
LONG TERM...
/FRIDAY NIGHT THROUGH THURSDAY/
AN UPPER LEVEL LOW CONTINUES TO SPIN IN NORTH CENTRAL MEXICO
TODAY. THIS WILL MOVE NORTH INTO WEST TEXAS THROUGH
SATURDAY...BEFORE MOVING OFF TO THE NORTHEAST SATURDAY NIGHT. HAVE
KEPT IN SLIGHT CHANCE TO CHANCE POPS FOR THE AREA FRIDAY NIGHT
THROUGH SATURDAY. HAVE KEPT HIGHER POPS TO THE WEST AS THE ECMWF
CONTINUES TO BE THE LONE MODEL WITH THE HIGHEST PROBABILITY OF
PRECIPITATION ACROSS THE CENTRAL PART OF THE FORECAST AREA. WITH
PRECIPITABLE WATERS INCREASING TO NEAR 1.75 INCHES...AND THE SLOW
MOVING NATURE OF THE STORMS...WE MAY SEE SOME LOCALLY HEAVY
RAINFALL AND MINOR FLOODING UNDER THE STRONGER STORMS. IN
ADDITION...DANGEROUS CLOUD TO GROUND LIGHTNING AND GUSTY WINDS
WILL BE POSSIBLE...BUT WIDESPREAD SEVERE WEATHER IS NOT EXPECTED.
FOLLOWING OUR RAIN CHANCES THROUGH SATURDAY...A WEAK RIDGING TO
ZONAL PATTERN IS EXPECTED TO SET UP ACROSS THE SOUTHWEST U.S. THIS
WILL BRING WARMER WEATHER BACK INTO THE AREA THROUGH THE REST OF
THE FORECAST. HOWEVER...HEIGHTS/THICKNESSES ARE NOT EXPECTED TO
REACH THE SAME LEVELS AS WERE EXPERIENCED EARLIER THIS WEEK...SO
HIGHS SHOULD STAY BELOW TRIPLE DIGIT VALUES FOR THE MOST PART.
HAVE GONE AHEAD AND INTRODUCED SOME SLIGHT CHANCE POPS FOR
NORTHERN AREAS MONDAY NIGHT INTO TUESDAY OF NEXT WEEK. MEDIUM
RANGE GUIDANCE AGREES THAT A COLD FRONT WILL MOVE SOUTH INTO THE
RED RIVER VALLEY OR JUST SOUTH OF THERE BY EARLY NEXT WEEK AS A
RESULT OF A SFC HIGH PRESSURE BUILDING ACROSS THE CENTRAL/SOUTHERN
PLAINS BEHIND AN UPPER LEVEL LOW MOVING THROUGH THE GREAT LAKES.
THE ECMWF AND CANADIAN MODELS CARRY PRECIPITATION FARTHER SOUTH
INTO THE CONCHO VALLEY AND HEARTLAND...BUT WILL HOLD POPS NORTH OF
THE INTERSTATE 20 CORRIDOR FOR NOW AS FLOW ALOFT IS EXPECTED TO BE
FAIRLY WEAK AND WESTERLY IN OUR AREA...AND JUST HOW FAR SOUTH THE
FRONT WILL MAKE IT IS QUESTIONABLE THIS TIME OF THE YEAR.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 73 90 71 92 73 / 5 10 20 30 10
SAN ANGELO 72 89 71 93 73 / 30 30 30 30 10
JUNCTION 72 86 71 92 72 / 20 30 20 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
242 AM PDT Fri Jun 14 2013
.SYNOPSIS...
Scattered mountain showers are expected today as temperatures still
remain on the cool side. Drier and much warmer weather can be
expected for the weekend. The next weather system will arrive by
Monday and bring more showery and cool weather for much of the
upcoming work week.
&&
.DISCUSSION...
Today and tonight...The Inland NW will be under the influence of an
exiting upper level trough of low pressure and cold air for the
next 24 hours. Currently this trough resides across eastern
Washington. Most of the daytime convection has diminished, but
radar does show some light shower activity associated with a few
upper level impulses and terrain. Of the upper level disturbances,
there are two main ones that we will be monitoring. The first is
within the base of the upper level trough and is pivoting across
the northeast Oregon and the Clearwater mountains into southwest
Montana with a band of light showers and embedded thunderstorms.
This area continues to pull away from our region and may brush our
southeast borders with mid level clouds and a few early morning
sprinkles. The other impulse is seen on satellite dropping south
from BC down the Okanogan valley. The Kelowna radar does show
light showers, and if they hold together, they could reach Omak
and Republic early this morning. Updated the early morning grids
to reflect this trend. The HRRR does pick up on these light
showers and spreads them from the Okanogan Valley and Highlands,
toward Colville and Sandpoint area early Friday morning as the
upper level trough axis shifts east. Daytime heating and surface
based instability will be enhanced within the upper level trough
axis which will be over northeast Washington and north Idaho
during the afternoon and early evening. Cape values will reach
near 400 j/kg, not as steep as yesterday but enough for the
potential of a couple embedded thunderstorms especially over the
mountains. Meanwhile, a more stable, dry westerly flow will
develop across the western zones. The instability will quickly
decrease after mid evening as an upper level ridge of high
pressure builds into the region with drying and clearing Friday
night. Although temperatures will moderate gradually today and
tonight, they will still be cooler than normal. /rfox.
Saturday and Saturday night: As the Low exits the region a ridge will
build into Eastern Washington...bringing drier and warmer weather
to much of the forecast area. Weak diffluence and daytime heating
will begin to affect the Cascades by Saturday afternoon, leading
to potential showers or isolated thunderstorm along the crest of
the Cascades. The next Low pressure will move into position just
of the coast of northern BC. /JDC
Sunday through Monday...Model agreement is good and consistent
over previous runs in depicting an increasingly moist and deep
southerly flow regime over the forecast area as a new upper level
low slowly approaches the forecast area off the Pacific. This
pattern strongly argues fro increasing temperatures each day...as
will as the return of a perceptible convective threat...probably
beginning Sunday mainly over the Cascades and on Monday broadening
out to include a chance of showers and thunderstorms over the
mountains ringing the basin...but also a smaller threat of a stray
shower or afternoon thunderstorm over the basin. Moisture and
instability will be increasing...but so far models do not sense
any especially stimulating short wave or disturbance necessary to
trigger widespread convection. An unsettled early summer-like
regime would best characterize this period of the forecast.
Monday night through Thursday...This period will cover the passage
directly aloft of the incoming closed low. For the last few days
the EC and GFS have been consistent and in reasonable agreement
in tracking this upper low directly across the forecast area. Two
distinct events are becoming increasingly likely during this
evolution...the first will be another day of increased convective
activity as the increasingly moist southerly flow continues to
impact the region on Tuesday...showers and thunderstorms will be
hit-and-miss but highly likely to be prowling most of the
forecast area justifying solid chance pops...with high
temperatures cooler than previous days but only down to around
seasonal normal values.
By Wednesday and Thursday there is an increased likelihood that a
much wetter and cooler pattern will develop as the low center
passes directly over the region...and on at least one of these
days...at this time Wednesday looks like the best bet but
Thursday also a possibility...or maybe both days...a downright wet dense
shower/stratiform rain event associated with a deformation band
will develop probably over the east and north reaches of the
forecast area. Model details are still a little nebulous that far
out but in good agreement with the overall pattern which
historically implies a wetter solution than climatology would
suggest. /Fugazzi
&&
.AVIATION...
06Z TAFS: Stronger showers and thunderstorms have ended this
evening. Some light shower activity will continue across the
Cascade crest, northeast mountains, and in the vicinity of
KLWS/PUW tonight. There is a possibility of patchy fog and/or
stratus/low cloud development from about 10Z on to 18Z for
KLWS/KCOE where more significant showers fell earlier, but
confidence is low. Drier conditions will prevail for all TAF
sites Friday with scattered showers possible for the Idaho
panhandle. /EK
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 68 47 77 53 84 56 / 20 10 0 0 10 10
Coeur d`Alene 67 42 77 50 85 53 / 20 20 0 0 10 10
Pullman 68 38 77 47 84 49 / 20 10 0 0 0 10
Lewiston 75 48 85 54 91 56 / 20 0 0 0 0 10
Colville 74 45 81 49 88 54 / 40 20 0 0 20 20
Sandpoint 68 39 77 45 85 48 / 30 30 0 0 10 10
Kellogg 67 43 73 50 82 54 / 40 10 0 0 10 10
Moses Lake 77 46 86 57 90 59 / 10 0 0 0 10 20
Wenatchee 75 52 85 63 89 61 / 0 0 0 10 10 20
Omak 75 45 83 54 87 57 / 20 0 0 10 20 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
329 AM CDT FRI JUN 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CDT FRI JUN 14 2013
MAIN FORECAST FOCUS IS ON POTENTIAL FOR HEAVY RAIN/FLASH FLOODING
LATER TODAY THROUGH SATURDAY.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A HIGHLY AMPLIFIED PATTERN ACROSS NORTH AMERICA...CONSISTING
OF TROUGHING OVER ALBERTA AND IDAHO...RIDGING FROM THE SOUTHERN
PLAINS INTO MANITOBA...AND TROUGHING FROM SOUTHEAST CANADA SOUTHWARD
ALONG THE EAST COAST OF THE U.S.. THE FORECAST AREA LIES ON THE
SUBSIDENT SIDE OF THE RIDGING...RESULTING IN HIGH PRESSURE AT THE
SURFACE WHICH EXISTS OVER WISCONSIN. 00Z SOUNDINGS FROM MPX...GRB
AND DVN DEPICTED A DRY AIRMASS WITH THIS HIGH PRESSURE AREA WITH
PRECIPITABLE WATER VALUES OF 0.7-0.8 INCHES OR 80-90 PERCENT OF
NORMAL. THE DRY AIRMASS HAS HELPED KEEP SKIES MOSTLY CLEAR OVERNIGHT
AND WITH LIGHT WINDS...TEMPERATURES HAVE DROPPED INTO THE UPPER 40S
TO UPPER 50S. MEANWHILE...TO THE WEST UNDER AND WEST OF THE UPPER
RIDGE AXIS...MOISTURE HAS BEEN GRADUALLY ADVECTING NORTHWARD THROUGH
THE PLAINS ON A 30-45 KT 850MB JET PER VWP DATA. GOES DERIVED
PRECIPITABLE WATER SHOWED VALUES OF 1-1.5 INCHES ACROSS MUCH OF THE
PLAINS...HIGHEST ACROSS SOUTH CENTRAL NEBRASKA AND NORTH CENTRAL KS.
THIS MAXIMA WAS ALSO CORRELATED WITH THE REMNANTS OF AN MCS THAT
INITIATED OFF THE FRONT RANGE IN COLORADO YESTERDAY AFTERNOON. ALONG
WITH THE INCREASED MOISTURE...00Z RAOBS SHOWED 850MB TEMPS OF 16-21C
FROM RAPID CITY TO OMAHA AND TOPEKA...QUITE A BIT WARMER COMPARED TO
THE 10-13C AROUND THE FORECAST AREA. ALONG THE GRADIENT OF THIS
TEMPERATURE DIFFERENCE...A NARROW LINE OF SHOWERS AND THUNDERSTORMS
HAS BROKE OUT OVER SOUTHWEST MN INTO WESTERN IA.
OVER THE NEXT 24 HOURS...THE UPPER RIDGE AXIS OVER THE PLAINS IS
PROGGED TO SHIFT EAST OVER THE FORECAST AREA. THIS IS IN RESPONSE TO
THE TROUGH OVER IDAHO AND ALBERTA EJECTING NORTHEAST...AS WELL AS
FORMING A DEEP CLOSED LOW CIRCULATION OVER CENTRAL SASKATCHEWAN.
WHAT THIS MEANS FOR THE FORECAST AREA IS ALL OF THAT WARMER 850MB
AIR AND HIGHER PRECIPITABLE WATER UNDER THE UPPER RIDGE WILL MOVE
TOWARDS US. GIVEN THE WARM ADVECTION PATTERN...EXPECT CONCERN FOR
PRECIPITATION TO INCREASE. IN ADDITION...CONVECTIVELY INDUCED
SHORTWAVES FROM CONVECTION COMING OFF THE ROCKIES AND THE PLAINS
THIS MORNING...AND THOSE THAT FIRE THIS AFTERNOON...WILL ALSO PLAY A
ROLE AS THEY HEAD NORTHEAST AROUND THE UPPER RIDGE.
FOR TODAY...GENERAL CONSENSUS FROM THE MODELS IS FOR INCREASING
310-315K ISENTROPIC LIFT AND 700MB MOISTURE TRANSPORT TO COME ACROSS
THE FORECAST AREA DURING THE AFTERNOON. ANTICIPATING AN
ALTOSTRATUS/ACCAS DECK TO FORM AS A RESULT AND OVERSPREAD MUCH OF
THE AREA. THIS CAN ALREADY BE SEEN ALONG THE DAKOTAS/MN BORDER WHERE
THOSE SHOWERS AND THUNDERSTORMS HAVE BEEN OCCURRING. HAVE
CONTINUED THE MENTION OF SOME LOW PROBABILITIES FOR PRECIPITATION
WEST OF THE MS RIVER EARLY THIS AFTERNOON TO ACCOUNT FOR THIS SHOWER
POTENTIAL.
LATE IN THE AFTERNOON...SOMETHING TO WATCH IS THE 14.00Z NAM
SCENARIO WHICH DEPICTS A LARGER AMOUNT OF CONVECTION OVER SOUTH
CENTRAL MN AND NORTH CENTRAL IA...CLIPPING FAR WESTERN PORTIONS OF
THE FORECAST AREA. THE GFS/ECMWF/REGIONAL CANADIAN ARE VERY
SIMILAR...THOUGH QPF VALUES ARE NOT NEARLY AS HIGH WHICH MAY BE A
RESULT OF MODEL RESOLUTION. THE SITUATION APPEARS TO BE A RESULT OF
INCREASING 700-850MB MOISTURE TRANSPORT...ON THE LEADING EDGE OF THE
HIGHER PRECIPITABLE WATER VALUES OF 1.5-1.8 INCHES PER RAP COMING
INTO WESTERN IA...CAPE OF 1000 J/KG OR SO THAT IS UNCAPPED LIFTED
FROM 725MB...AND A POSSIBLE RIGHT ENTRANCE REGION OF A JET STREAK
TRACKING SOUTHEAST THROUGH WISCONSIN. SHOULD THIS PAN OUT...GIVEN
THE HIGH PRECIPITABLE WATER...THESE STORMS WILL BE HEAVY RAIN
PRODUCERS.
NAM/GFS/ECMWF/REGIONAL CANADIAN MOISTURE TRANSPORT FIELDS FROM
925-700MB ARE ALL IN AGREEMENT THAT THE STREAM SHIFTS NORTHEAST
TONIGHT...FOLLOWING THE UPPER RIDGE AXIS. THUS...THINKING THE
CONVECTION THAT FIRES LATE THIS AFTERNOON SHOULD SLOWLY PROGRESS
EASTWARD THROUGH THE FORECAST AREA. ADDITIONALLY...IT APPEARS THERE
IS A SECOND SURGE OF MOISTURE TRANSPORT COMING UP OUT OF KS INTO
CENTRAL IA OVERNIGHT...LIKELY FIRING MORE CONVECTION ON ITS NOSE
FROM NORTH CENTRAL INTO EASTERN IA. THE ECMWF HAS BEEN EXTREMELY
CONSISTENT RUN TO RUN WITH THIS.
ALTHOUGH INSTABILITY IS ADVECTING TOWARDS US ON THIS MOISTURE
TRANSPORT...THE INSTABILITY IS TALL AND SKINNY. WITH WARM CLOUD
DEPTHS APPROACHING 14 KFT...THINKING HEAVY RAIN WOULD BE THE MAIN
SEVERE WEATHER CONCERN. ADDITIONALLY...THE 2-7KM SHEAR WHICH IS MORE
REPRESENTATIVE OF THE INSTABILITY USED BY THE STORMS...IS LESS THAN
30 KTS. SEE THE HYDROLOGY SECTION BELOW FOR MORE ON THE IMPACTS FROM
THE PRECIPITATION. MAIN THING TO NOTE HERE IS THAT GIVEN THE MOIST
SOILS OVER PORTIONS OF NORTHEAST IA AND SOUTHEAST MN...ANY HEAVY
RAIN MAY CAUSE FLASH FLOODING...ESPECIALLY IN FLOYD AND MITCHELL
COUNTIES IN IA. THEREFORE...HAVE ISSUED FLASH FLOOD WATCHES FOR THE
MOST CONCERNING AREAS.
850MB TEMPERATURES ARE PROGGED TO STAY BETWEEN 10-13C TODAY. WITH
INCREASING CLOUDS...TEMPERATURES SHOULD END UP NEAR OR A LITTLE
BELOW YESTERDAY HIGHS. WARMER NIGHT ON TAP AS HIGHER DEWPOINTS MOVE
IN ACCOMPANYING THE HIGHER PRECIPITABLE WATER.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 329 AM CDT FRI JUN 14 2013
SATURDAY THROUGH MONDAY...
MODELS ARE IN GOOD AGREEMENT FLATTENING THE UPPER RIDGE OVER THE
AREA ON SATURDAY...AGAIN RESULTING FROM THE EJECTING IDAHO TROUGH.
EVENTUALLY...THE CLOSED UPPER LOW THAT FORMED OVER SASKATCHEWAN ON
SATURDAY WILL APPROACH THE AREA...PROGGED TO DROP INTO CENTRAL MN AT
12Z MONDAY AS A SHORTWAVE TROUGH. THIS TROUGH MAY EVEN BEGIN TO
PHASE WITH THE GENERAL TROUGHING OVER SOUTHEAST CANADA AS INDICATED
BY THE 00Z ECMWF.
WITH THE FLOW TURNING ZONAL ON SATURDAY...THE MAIN MOISTURE
TRANSPORT STREAM SUPPORTING CONVECTION TONIGHT SHOULD PUSH OFF TO
THE EAST. THUS...LIKE CLIMATOLOGY FOR NOCTURNAL CONVECTION...
EXPECTING IT TO WEAKEN THROUGH THE MORNING HOURS. HOWEVER...OUTFLOW
BOUNDARIES FROM THE CONVECTION AND WHAT SHOULD BE A COLD FRONT AT
THE SURFACE ARE SUGGESTED TO LAY UP OVER SOUTHERN SECTIONS OVER THE
FORECAST AREA. GROWING INSTABILITY FROM ANY DAYTIME HEATING PLUS A
HUMID AIRMASS CHARACTERIZED BY DEWPOINTS IN THE MID-UPPER
60S...ALONG WITH PRECIPITABLE WATER VALUES OF 1.5-1.8 INCHES...
SHOULD PROMOTE RENEWED CONVECTION. AGAIN...HEAVY RAIN WOULD BE THE
MAIN CONCERN AND THUS THE FLASH FLOOD WATCH GOES THROUGH THE DAY
SATURDAY. OUTFLOWS FROM THIS NEW CONVECTION COMBINED WITH THE COLD
FRONT DROPPING SOUTHEAST SHOULD PUSH MUCH OF THE CONVECTION OUT OF
THE AREA SOMETIME DURING THE EVENING. EXACT TIMING STILL HARD TO PIN
DOWN. LEFT SOME LOW CHANCES IN AFTER MIDNIGHT INTO THE DAY SUNDAY
ACROSS FAR SOUTHERN SECTIONS OF THE AREA WITH THE 14.00Z GFS/ECMWF
SHOWING SOME LIGHT QPF LINGERING. HOWEVER...BELIEVE THESE MIGHT BE
ABLE TO BE REMOVED IN LATER FORECASTS WITH A WEAK RIDGE OF HIGH
PRESSURE IN PLACE. ATTENTION SUNDAY NIGHT AND MONDAY TURNS TO THE
TROUGHING DROPPING INTO MINNESOTA. DPVA AHEAD OF THE TROUGH PLUS A
SURGE OF 850-700MB MOISTURE TRANSPORT MAY BE ENOUGH TO KICK OFF SOME
SHOWER AND THUNDERSTORM ACTIVITY. HOWEVER...THE TROUGH IS COMING
THROUGH AT THE WRONG TIME OF DAY TO GET EXCITED ABOUT IT...AND
MOISTURE IS LACKING WITH PRECIPITABLE WATER VALUES MAYBE AROUND 1
INCH. THEREFORE...HAVE ONLY WENT WITH 20-40 PERCENT CHANCES ACROSS
THE FORECAST AREA. 13.12Z/14.00Z ECMWF EVEN SUGGESTS THE TROUGH AND
ITS ASSOCIATED COLD FRONT COULD COME THROUGH THE AREA MAINLY DRY.
WITH WARMER 850MB TEMPS ON SATURDAY...14-17C...AND MORE SUNSHINE ON
SUNDAY WITH SIMILAR READINGS...EXPECT TEMPERATURES TO RISE EACH DAY.
MOST LOCATIONS SHOULD SEE GOOD MIXING ON SUNDAY...BOOSTING HIGHS
INTO THE LOW TO MID 80S. COOLER READINGS ON TAP FOR MONDAY WITH THE
COLD FRONT COMING THROUGH. GENERALLY FOLLOWED A BLEND OF GUIDANCE
FOR HIGHS AND LOWS.
MONDAY NIGHT THROUGH THURSDAY...
VERY GOOD MODEL AGREEMENT EXISTS AMONGST THE 14.00Z
ECMWF/GFS/CANADIAN AND GFS ENSEMBLES ON THE UPPER LEVEL PATTERN.
MUCH OF THE PERIOD IS DOMINATED BY TROUGHING ALONG THE U.S. WEST
COAST...RIDGING FROM THE NORTHWEST TERRITORIES OF CANADA INTO THE
CENTRAL PLAINS...AND TROUGHING OVER EASTERN CANADA INTO THE GREAT
LAKES. THIS MEANS MOSTLY A NORTHWEST FLOW OF COOL AND DRY AIR FROM
CANADA. THUS...MUCH OF THE FORECAST IS DRY. THERE ARE INDICATIONS OF
A SHORTWAVE DROPPING THROUGH THE WESTERN GREAT LAKES ON
THURSDAY...BRINGING A COLD FRONT INTO THE AREA. HAVE INCLUDED 20
PERCENT CHANCES FOR SHOWERS AND THUNDERSTORMS NORTH OF I-90 FOR THIS
FEATURE. TEMPERATURE WISE...THE COOLEST DAY LOOKS TO BE TUESDAY WITH
HIGH PRESSURE OVERHEAD AND 850MB TEMPS OF 8-10C. AIRMASS
MODIFICATION THANKS TO THE STRONG JUNE SUN SHOULD HELP WARM
TEMPERATURES EACH DAY THEREAFTER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY EVENING)
ISSUED AT 1145 PM CDT THU JUN 13 2013
HIGH PRESSURE BUILDS ACROSS THE REGION TONIGHT...WITH SKC SKIES AND
VRB TO LIGHT EAST WINDS. HIGH CLOUDS WILL BE ON THE INCREASE FRI
AFTERNOON...AHEAD OF AN ANTICIPATED AREA OF SHRA/TS MOVING NORTHEAST
AHEAD OF A WARM FRONT. PCPN IS LIKELY FOR KRST/KLSE FRIDAY NIGHT
INTO SATURDAY...WITH A LOWERING IN CIG HEIGHTS AS THE SHRA/TS MOVE
IN. PERIODS OF MVFR APPEARS LIKELY AT THIS TIME...WITH SOME
RESTRICTIONS IN VSBY. PARAMETERS SUGGEST THAT THE SHOWERS AND STORMS
COULD BE EFFICIENT RAIN PRODUCERS...AND HEAVY RAIN WILL BE POSSIBLE.
WINDS WILL INCREASE AND TURN FROM EAST TO SOUTHEAST ON FRIDAY.
SOME MESO MODELS ARE SUGGESTING THE POTENTIAL FOR SCT/ISOLD
SHRA/TS AHEAD OF THE EXPECTED PCPN FOR FRIDAY NIGHT...DEVELOPING IN
THE MID LEVEL WARM AIR ADVECTIVE WING OF THE APPROACHING SYSTEM. AT
THIS TIME...ANYTHING THAT WOULD DEVELOP WOULD COME OUT OF A MID /10
KFT/ LEVEL CLOUD DECK...WITH MINIMAL/IF ANY ACCUMULATIONS. ACTIVITY
IS NOT A FOR SURE THING...AND LOOKS LIMITED IN AREAL EXTENT...SO
WILL LEAVE OUT OF THE TAFS FOR NOW.
&&
.HYDROLOGY...LATE THIS AFTERNOON THROUGH SATURDAY
ISSUED AT 329 AM CDT FRI JUN 14 2013
VERY WET SOILS ACROSS MOWER AND FILLMORE COUNTIES IN MN ALONG WITH
MUCH OF NORTHEAST IOWA OVER THE PAST WEEK...AND REALLY THE PAST
COUPLE MONTHS...RESULT IN A HUGE CONCERN FOR FLOODING. THAT 1-2
INCHES OF RAINFALL THAT IMPACTED FLOYD COUNTY IA LATE WEDNESDAY...
MOSTLY IN A SHORT TIME PERIOD...CAUSED A LOT OF FLOODING ISSUES.
EXPECTING A BAND OF THUNDERSTORMS TO MOVE INTO MOWER THROUGH FLOYD
COUNTIES LATE THIS AFTERNOON...SLOWLY MOVING EAST THROUGH THE
EVENING. ADDITIONAL THUNDERSTORMS ARE FORECAST AFTER MIDNIGHT AND
THROUGH MUCH OF THE DAY SATURDAY SOUTH OF I-90. WITH PRECIPITABLE
WATER VALUES OF 1.5-1.8 INCHES AND WARM CLOUD DEPTHS OF 3500-4200
METERS ACCOMPANYING THESE THUNDERSTORMS...HEAVY RAIN IS LIKELY. WE
COULD BE LOOKING AT A WIDESPREAD 1-2 INCHES OF RAINFALL SOUTH OF
I-90...HIGHEST ACROSS NORTHEAST IOWA. LOCALLY HEAVIER RAINFALL IS
EASILY POSSIBLE.
GIVEN THE VERY WET SOILS AND POTENTIAL FOR HEAVY RAIN...HAVE ISSUED
A FLASH FLOOD WATCH FOR MOWER AND FILLMORE COUNTIES IN MN AND MUCH
OF NORTHEAST IA EXCEPT ALLAMAKEE. DEPENDING ON HOW CONVECTION
EVOLVES...THE WATCH MAY NEED TO BE EXPANDED EASTWARD...MOST LIKELY
INTO FAR SOUTHWEST WI.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...FLASH FLOOD WATCH FROM THIS AFTERNOON THROUGH SATURDAY EVENING
FOR MNZ094-095.
IA...FLASH FLOOD WATCH FROM THIS AFTERNOON THROUGH SATURDAY EVENING
FOR IAZ008>010-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION......RIECK
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
946 AM MDT FRI JUN 14 2013
.UPDATE...
&&
.SHORT TERM...WEAK FNT WAS MOVING ACROSS NERN CO THIS MORNING
WITH DRIER AIR BEHIND FNT. AT THIS POINT LOOKS LIKE BEST AREA FOR
TSTM DEVELOPMENT THIS AFTN WILL BE OVER THE PALMER DIVIDE TOWARDS
THE LIMON AREA. ALONG THE FRONT RANGE AND FURTHER NORTH EXPECTED
ISOLD TO WDLY SCT HIGHER BASED STORMS. THERE WILL BE SOME SVR
POTENTIAL MAINLY OVER ERN ELBERT AND LINCOLN COUNTIES.
.AVIATION...WK BNDRY WAS OVER DIA WITH WINDS SHIFTING TO NNE. BY
EARLY AFTN LATEST RAP SHOWS A WK DENVER CYCLONE DEVELOPING OVER
ERN DOUGLAS COUNTY WITH LOW LVL WINDS BECOMING MORE ELY AND
CONTINUING THRU MOST OF THE AFTN. AT THIS TIME LOOKS LIKE BEST CHC
FOR TSTMS WILL BE S AND SE OF DIA HOWEVER THERE STILL COULD BE
SOME ISOLD HIGHER BASED STORMS SO WILL KEEP VCNTY IN THE TAF. FOR
TONIGHT ANOTHER FNT WILL AFFECT THE AREA AFTER MIDNIGHT WITH
AREAS OF STRATUS DEVELOPING BY 12Z SAT. WINDS THIS EVENING WILL BE
SELY AND THEN BECOME MORE NLY AFTER MIDNIGHT.
&&
.FIRE WEATHER...HUMIDITY LEVELS WILL BE VERY LOW IN THE HIGHER
VALLEYS AND SRN FOOTHILLS HOWEVER WINDS WILL STAY BLO 20 MPH IN
MOST AREAS SO WILL NOT ISSUE ANY RED FLAG WARNINGS
&&
.HYDROLOGY...ISOLD HIGH BASED STORMS WILL BE POSSIBLE HOWEVER VERY
LITTLE RAINFALL WILL OCCUR.
&&
.PREV DISCUSSION... /ISSUED 349 AM MDT FRI JUN 14 2013/
SHORT TERM...SOUTHWEST FLOW ALOFT WILL CONTINUE TODAY. DRIER AIR
OVER UTAH AND WESTERN COLORADO WILL SHIFT EAST ACROSS THE STATE THIS
MORNING. DEW POINTS ARE ALREADY FALLING INTO 30S ACROSS THE DENVER
AREA. A LACK OF MOISTURE SHOULD KEEP ANY SHOWERS AND STORMS EAST OF
I-25. MOISTURE NOT THAT GREAT OVER EASTERN COLORADO EITHER WITH DEW
POINTS DROPPING INTO THE UPPER 30S TO LOWER 40S. A WEAK COLD FRONT
WITH ONLY FEW DEGREES OF COOLING WILL PUSH SOUTH ACROSS EASTERN
COLORADO THIS MORNING. THIS FRONT WILL STALL OVER THE PALMER DIVIDE
AND ALONG I-70 SOUTHEAST OF DENVER. CONVERGENCE ALONG THIS BOUNDARY
WILL LIKELY TRIGGER A FEW SHOWERS AND STORMS THIS AFTERNOON AND
EVENING. MOST OF THE MODELS ARE SHOWING SOME ACTIVITY IN THIS AREA.
TEMPERATURES IN THE UPPER 80S WITH DEW POINTS IN THE LOWER 40S YIELD
SURFACE BASED CAPES IN THE 400-800 J/KG RANGE. COULD GET A SEVERE
WIND GUST OR TWO DUE TO THE DRY SUB CLOUD LAYER...OTHERWISE NO
WIDESPREAD SEVERE WEATHER IS EXPECTED.
WINDS WILL TURN EASTERLY ACROSS NORTHEAST COLORADO THIS AFTERNOON
BEHIND THE FRONT. MOISTURE WILL START TO INCREASE AGAIN LATE THIS
AFTERNOON...BUT MORE SO THIS EVENING. THIS INCREASE IN MOISTURE
COMBINED WITH WEAK LIFT FROM A JET TO THE NORTH COULD PRODUCE A FEW
WEAK SHOWERS OR STORMS OVER NORTHEAST COLORADO. WILL HAVE 10-20 POPS
FOR THIS WITH HIGHER POPS ALONG I-70 SOUTHEAST OF DENVER WHERE THE
BETTER LIFT WILL BE.
STRONGER COLD FRONT WILL ENTER NORTHEAST COLORADO AFTER MIDNIGHT
TONIGHT. LOW CLOUDS WILL DEVELOP BEHIND THE FRONT AFTER 09Z AND THEN
SPREAD SOUTH ACROSS NORTHEAST COLORADO AROUND SUNRISE SATURDAY
MORNING.
LONG TERM...NOT MUCH IN TERMS OF ADJUSTMENT FROM THE PREVIOUS
FORECAST. SATURDAY WILL BE COOLER...FOLLOWING THE PASSAGE OF A
COLD FRONT FRIDAY NIGHT. THE NAM12 SPATIAL CROSS SECTIONS INDICATE
A FAIRLY THICK LAYER OF STRATUS IN THE LOWER LEVELS...WHICH WILL
LIKELY TAKE UNTIL LATE MORNING/EARLY AFTN TO COMPLETELY BURN OFF.
THE MDLS SOUNDINGS STILL SHOW VERY FAVORABLE CAPE IN THE AFTN
WITH VALUES IN THE 1200-1600 J/KG RANGE AT KDEN...KLIC AND KAKO.
MAIN QUESTION WILL BE IF AND WHEN THE CAP WILL BE ELIMINATED.
POTENTIAL FOR A FEW SEVERE THUNDERSTORMS WITH FAVORABLE SHEAR IN
PLACE. ON SUNDAY...IT MAY BE A LITTLE DRIER FROM THE FRONT RANGE
FOOTHILLS WESTWARD...BUT STILL A CHANCE OF TSTMS ESPECIALLY ACROSS
THE NORTHEASTERN PLAINS WHERE EVER THE LOW LEVEL THETA-E
CONVERGENCE OCCURS. ANOTHER COLD FRONT IS PROGGED TO MOVE INTO
NORTHEAST COLORADO SUNDAY NIGHT...WITH SIMILAR CONDITIONS TO
SATURDAY SETTING UP FOR MONDAY. THE AIRMASS WILL START TO DRY OUT
TUESDAY THROUGH THURSDAY AS THE SOUTHWESTERLY FLOW ALOFT OVER THE
STATE INCREASES...AND THE LOW LEVEL MOISTURE OVER THE NORTHEAST
PLAINS SHIFTS TO THE EAST. FIRE DANGER MAY AGAIN START TO ELEVATE
WITH HIGH TEMPERATURES PROGGED TO WARM INTO THE UPPER 80S BY
MIDWEEK.
AVIATION...SOUTH TO SOUTHWEST WINDS WITH GUSTS TO 20 KNOTS WILL
WEAKEN AND TURN WESTERLY AROUND 12Z. WINDS WILL CONTINUE TO TURN
CLOCKWISE DURING THE MORNING HOURS AS A WEAK COLD FRONT PUSHES
ACROSS THE AREA. AROUND 18Z...WINDS WILL BE EASTERLY AND REMAIN
EASTERLY THROUGH THE AFTERNOON. ISOLATED THUNDERSTORMS WILL
DEVELOP AFTER 19Z...MAINLY SOUTHEAST OF DENVER...THOUGH ONE CAN
NOT BE RULED OUT FOR THE DENVER AREA. THE DENVER AIRPORTS WILL
HAVE A BETTER CHANCE AT SEEING AN OUTFLOW BOUNDARY OR TWO.
ANOTHER COLD FRONT WILL PUSH THROUGH NORTHEAST COLORADO LATE
TONIGHT. LOW CLOUDS WITH CEILINGS BELOW 3000 FEET WILL DEVELOP
BEHIND THE FRONT LATE FRIDAY NIGHT AND CONTINUE INTO SATURDAY
MORNING.
HYDROLOGY...NO CONCERNS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....COOPER
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS PUEBLO CO
918 AM MDT FRI JUN 14 2013
.UPDATE...
ISSUED AT 916 AM MDT FRI JUN 14 2013
UPDATED THE GRIDS TO INCREASE CLOUD COVER ACROSS THE AREA OVER THE
NEXT FEW HOURS. -PJC
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM MDT FRI JUN 14 2013
SOUTHWEST FLOW ALOFT CONTINUES OVER THE AREA TODAY AND TONIGHT...AS
STRONG UPPER TROUGH LIFTS NORTHEAST FROM THE NORTHERN ROCKIES INTO
THE CANADIAN PRAIRIE. RATHER DIFFUSE SURFACE FRONT OVER THE EASTERN
PLAINS HAS BEEN GRADUALLY DRIFTING BACK EASTWARD THIS MORNING...WITH
WARMER/DRIER AIR MASS SPREADING EAST FROM THE MOUNTAINS ACROSS THE
I-25 CORRIDOR. OVERALL...WINDS TODAY LOOK LESS THAN THE PAST FEW
DAYS AS MID LEVEL FLOW DECREASES AND SURFACE GRADIENT RELAXES. FAR
SOUTHEAST PLAINS...MAINLY BACA COUNTY...COULD GET FAIRLY WINDY AHEAD
OF LEE SURFACE TROUGH...THOUGH RH REMAINS JUST ABOVE 15 PERCENT AND
WILL REFRAIN FROM ISSUING A FIRE WX HIGHLIGHT. WITH THIN PLUME OF
MID LEVEL MOISTURE OVER THE AREA ONCE AGAIN...EXPECT ANOTHER ROUND
OF MAINLY ISOLATED AFTERNOON AND EVENING THUNDERSTORMS...WITH BEST
CHANCES ALONG AND EAST OF A TRINIDAD TO LA JUNTA TO EADS
LINE...WHERE DEWPOINTS HOLD IN THE 40S AND CAPES PUSH ABOVE 1000
J/KG. SOME CONCERN ABOUT LOW RH AND BRIEFLY GUSTY WINDS OVER
TELLER/EL PASO COUNTIES THIS AFTERNOON...AS SUCCESSIVE RUNS OF THE
HRRR/NAM HAVE TRENDED DRIER AND WINDIER THE PAST FEW HOURS. IN
FACT...LATEST HRRR DROPS DEWPOINTS INTO THE TEENS OVER NORTHERN EL
PASO COUNTY BY EARLY AFTERNOON...WHICH SUGGESTS FAIRLY DEEP
MIXING...THOUGH MODEL SURFACE/BL WINDS NEVER GET MUCH ABOVE 15
KNOTS. MAX TEMPS CONTINUE ON THE HOT SIDE...VERY SIMILAR TO
YESTERDAY. OVERNIGHT...CONVECTION LINGERS IN THE DEEPER MOISTURE
OVER THE FAR EASTERN PLAINS PAST SUNSET...THOUGH MOST AREAS SHOULD
SEE TSRA END BY MIDNIGHT AS POTENTIAL MCS LIFTS NORTHEAST INTO NEB.
SURFACE FRONT SHOULD GET A SOUTHWESTWARD SHOVE BY DEPARTING
CONVECTION...WITH LOW LEVEL MOISTURE SLOSHING BACK TO THE I-25
CORRIDOR AND EASTERN MOUNTAINS BY EARLY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 343 AM MDT FRI JUN 14 2013
SOME CHANGES TO THE EXTENDED FOR THE WEEKEND INTO EARLY NEXT WEEK.
MODEL SOLUTIONS HAVE AN UPPER LEVEL RIDGE ACROSS THE ROCKIES
SATURDAY THROUGH TUESDAY...WITH SEVERAL DISTURBANCES MOVING ACROSS THE
REGION UNDER THE RIDGE. THE MAIN MODEL DIFFERENCES ARE IN THE
AMOUNT AND TYPE OF CONVECTION THAT MAY BE POSSIBLE ACROSS THE
PLAINS. MOISTURE WILL BE THE BIGGEST COMPLICATION AND WILL
DETERMINE HOW MUCH PRECIPITATION FALLS WITH THUNDERSTORM ACTIVITY.
MOISTURE STILL LOOKS MODEST ON SATURDAY AND MODEL SOLUTIONS ARE
HINTING THAT THUNDERSTORM ACTIVITY MAY BE LIMITED. MODELS DEVELOP
THUNDERSTORMS OVER THE MOUNTAINS BY SATURDAY AFTERNOON...WITH SOME
MOVEMENT OVER THE PALMER DIVIDE AND RATON MESA THROUGH THE
EVENING. LIGHTNING AND STRONG WIND GUSTS...POSSIBLY AS HIGH WAS 50
MPH...WILL BE THE MAIN THREATS...WITH VERY LITTLE PRECIPITATION
ACTUALLY FALLING.
MODELS A BIT MORE IMPRESSIVE WITH PRECIPITATION CHANCES SUNDAY
THROUGH TUESDAY. MOISTURE WILL ADVECT NORTHWARD OUT OF THE DESERT
SOUTHWEST WHICH SHOULD LEAD TO MORE WIDESPREAD SHOWER AND
THUNDERSTORM ACTIVITY. EXPECT THUNDERSTORMS TO DEVELOP BY LATE
MORNING EACH DAY OVER THE MOUNTAINS...AND SPREAD EAST INTO THE
I-25 CORRIDOR BY THE AFTERNOON. THE GFS IS MOST IMPRESSIVE
DEVELOPING MCS EVENTS THAT PUSH EAST ACROSS THE PLAINS THROUGH THE
OVERNIGHT PERIODS. THIS WOULD BRING LOCALLY HEAVY RAINFALL UNDER
THE STORM SYSTEMS. FOR NOW HAVE WIDESPREAD LOW POPS ACROSS THE
REGION AND HOPEFULLY THE REGION SEES SOME BENEFICIAL RAINFALL.
AN UPPER LEVEL LOW WILL MOVE INTO THE PACIFIC NORTHWEST BY
WEDNESDAY WHICH WILL SPREAD STRONG DRY SOUTHWEST FLOW ACROSS THE
ROCKIES. THIS WILL LEAD TO DRY AND HOT CONDITIONS ACROSS COLORADO
ALONG WITH INCREASED RISK OF DANGEROUS FIRE WEATHER CONDITIONS.
AREAS OVER THE CONTINENTAL DIVIDE...SAN LUIS VALLEY AND EASTERN
MOUNTAINS WILL LIKELY SEE THE DANGEROUS CONDITIONS BY WEDNESDAY
AFTERNOON WHICH WILL SPREAD EAST ACROSS THE PLAINS FOR THURSDAY
AND FRIDAY. WE WILL CONTINUE TO MONITOR THE SITUATION FOR MID TO
LATE NEXT WEEK IN REGARDS TO FIRE WEATHER. MOZLEY
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 343 AM MDT FRI JUN 14 2013
VFR CONDITIONS EXPECTED AT ALL TAF SITES TODAY AND
TONIGHT. EXPECT ISOLATED TSRA OVER THE REGION AFTER 18Z...LASTING
UNTIL 02Z. MOST STORMS WILL BE HIGH BASED...LEADING TO POTENTIAL FOR
GUSTY/ERRATIC WINDS TO 40-45 KTS WITH ANY OUTFLOWS. COULD ALSO SEE
SOME OUTFLOW WIND DRIVEN AREAS OF BLOWING DUST OVER THE EASTERN
PLAINS BY LATE AFTERNOON...ESPECIALLY AROUND KLAA.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...PJC
SHORT TERM...PETERSEN
LONG TERM...MOZLEY
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS PUEBLO CO
446 AM MDT FRI JUN 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM MDT FRI JUN 14 2013
SOUTHWEST FLOW ALOFT CONTINUES OVER THE AREA TODAY AND TONIGHT...AS
STRONG UPPER TROUGH LIFTS NORTHEAST FROM THE NORTHERN ROCKIES INTO
THE CANADIAN PRAIRIE. RATHER DIFFUSE SURFACE FRONT OVER THE EASTERN
PLAINS HAS BEEN GRADUALLY DRIFTING BACK EASTWARD THIS MORNING...WITH
WARMER/DRIER AIR MASS SPREADING EAST FROM THE MOUNTAINS ACROSS THE
I-25 CORRIDOR. OVERALL...WINDS TODAY LOOK LESS THAN THE PAST FEW
DAYS AS MID LEVEL FLOW DECREASES AND SURFACE GRADIENT RELAXES. FAR
SOUTHEAST PLAINS...MAINLY BACA COUNTY...COULD GET FAIRLY WINDY AHEAD
OF LEE SURFACE TROUGH...THOUGH RH REMAINS JUST ABOVE 15 PERCENT AND
WILL REFRAIN FROM ISSUING A FIRE WX HIGHLIGHT. WITH THIN PLUME OF
MID LEVEL MOISTURE OVER THE AREA ONCE AGAIN...EXPECT ANOTHER ROUND
OF MAINLY ISOLATED AFTERNOON AND EVENING THUNDERSTORMS...WITH BEST
CHANCES ALONG AND EAST OF A TRINIDAD TO LA JUNTA TO EADS
LINE...WHERE DEWPOINTS HOLD IN THE 40S AND CAPES PUSH ABOVE 1000
J/KG. SOME CONCERN ABOUT LOW RH AND BRIEFLY GUSTY WINDS OVER
TELLER/EL PASO COUNTIES THIS AFTERNOON...AS SUCCESSIVE RUNS OF THE
HRRR/NAM HAVE TRENDED DRIER AND WINDIER THE PAST FEW HOURS. IN
FACT...LATEST HRRR DROPS DEWPOINTS INTO THE TEENS OVER NORTHERN EL
PASO COUNTY BY EARLY AFTERNOON...WHICH SUGGESTS FAIRLY DEEP
MIXING...THOUGH MODEL SURFACE/BL WINDS NEVER GET MUCH ABOVE 15
KNOTS. MAX TEMPS CONTINUE ON THE HOT SIDE...VERY SIMILAR TO
YESTERDAY. OVERNIGHT...CONVECTION LINGERS IN THE DEEPER MOISTURE
OVER THE FAR EASTERN PLAINS PAST SUNSET...THOUGH MOST AREAS SHOULD
SEE TSRA END BY MIDNIGHT AS POTENTIAL MCS LIFTS NORTHEAST INTO NEB.
SURFACE FRONT SHOULD GET A SOUTHWESTWARD SHOVE BY DEPARTING
CONVECTION...WITH LOW LEVEL MOISTURE SLOSHING BACK TO THE I-25
CORRIDOR AND EASTERN MOUNTAINS BY EARLY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 343 AM MDT FRI JUN 14 2013
SOME CHANGES TO THE EXTENDED FOR THE WEEKEND INTO EARLY NEXT WEEK.
MODEL SOLUTIONS HAVE AN UPPER LEVEL RIDGE ACROSS THE ROCKIES
SATURDAY THROUGH TUESDAY...WITH SEVERAL DISTURBANCES MOVING ACROSS THE
REGION UNDER THE RIDGE. THE MAIN MODEL DIFFERENCES ARE IN THE
AMOUNT AND TYPE OF CONVECTION THAT MAY BE POSSIBLE ACROSS THE
PLAINS. MOISTURE WILL BE THE BIGGEST COMPLICATION AND WILL
DETERMINE HOW MUCH PRECIPITATION FALLS WITH THUNDERSTORM ACTIVITY.
MOISTURE STILL LOOKS MODEST ON SATURDAY AND MODEL SOLUTIONS ARE
HINTING THAT THUNDERSTORM ACTIVITY MAY BE LIMITED. MODELS DEVELOP
THUNDERSTORMS OVER THE MOUNTAINS BY SATURDAY AFTERNOON...WITH SOME
MOVEMENT OVER THE PALMER DIVIDE AND RATON MESA THROUGH THE
EVENING. LIGHTNING AND STRONG WIND GUSTS...POSSIBLY AS HIGH WAS 50
MPH...WILL BE THE MAIN THREATS...WITH VERY LITTLE PRECIPITATION
ACTUALLY FALLING.
MODELS A BIT MORE IMPRESSIVE WITH PRECIPITATION CHANCES SUNDAY
THROUGH TUESDAY. MOISTURE WILL ADVECT NORTHWARD OUT OF THE DESERT
SOUTHWEST WHICH SHOULD LEAD TO MORE WIDESPREAD SHOWER AND
THUNDERSTORM ACTIVITY. EXPECT THUNDERSTORMS TO DEVELOP BY LATE
MORNING EACH DAY OVER THE MOUNTAINS...AND SPREAD EAST INTO THE
I-25 CORRIDOR BY THE AFTERNOON. THE GFS IS MOST IMPRESSIVE
DEVELOPING MCS EVENTS THAT PUSH EAST ACROSS THE PLAINS THROUGH THE
OVERNIGHT PERIODS. THIS WOULD BRING LOCALLY HEAVY RAINFALL UNDER
THE STORM SYSTEMS. FOR NOW HAVE WIDESPREAD LOW POPS ACROSS THE
REGION AND HOPEFULLY THE REGION SEES SOME BENEFICIAL RAINFALL.
AN UPPER LEVEL LOW WILL MOVE INTO THE PACIFIC NORTHWEST BY
WEDNESDAY WHICH WILL SPREAD STRONG DRY SOUTHWEST FLOW ACROSS THE
ROCKIES. THIS WILL LEAD TO DRY AND HOT CONDITIONS ACROSS COLORADO
ALONG WITH INCREASED RISK OF DANGEROUS FIRE WEATHER CONDITIONS.
AREAS OVER THE CONTINENTAL DIVIDE...SAN LUIS VALLEY AND EASTERN
MOUNTAINS WILL LIKELY SEE THE DANGEROUS CONDITIONS BY WEDNESDAY
AFTERNOON WHICH WILL SPREAD EAST ACROSS THE PLAINS FOR THURSDAY
AND FRIDAY. WE WILL CONTINUE TO MONITOR THE SITUATION FOR MID TO
LATE NEXT WEEK IN REGARDS TO FIRE WEATHER. MOZLEY
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 343 AM MDT FRI JUN 14 2013
VFR CONDITIONS EXPECTED AT ALL TAF SITES TODAY AND
TONIGHT. EXPECT ISOLATED TSRA OVER THE REGION AFTER 18Z...LASTING
UNTIL 02Z. MOST STORMS WILL BE HIGH BASED...LEADING TO POTENTIAL FOR
GUSTY/ERRATIC WINDS TO 40-45 KTS WITH ANY OUTFLOWS. COULD ALSO SEE
SOME OUTFLOW WIND DRIVEN AREAS OF BLOWING DUST OVER THE EASTERN
PLAINS BY LATE AFTERNOON...ESPECIALLY AROUND KLAA.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PETERSEN
LONG TERM...MOZLEY
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS MIAMI FL
1058 AM EDT FRI JUN 14 2013
.UPDATE...
FAIRLY QUIET MORNING WITH JUST A COUPLE OF ISOLATED LIGHT SHOWERS
TRYING TO DEVELOP ALONG THE GULF COAST. THE HRRR DOES SHOW
CONVECTION FIRING AFTER 18Z TODAY, WHICH DOES AGREE WITH THE GFS
AND ECMWF. SO HAVE KEPT 30 POPS IN FOR THE EASTERN HALF OF THE
FORECAST AREA.
&&
.PREV DISCUSSION... /ISSUED 732 AM EDT FRI JUN 14 2013/
AVIATION...
ALTHOUGH THE SHRA/TSTM COVERAGE WILL BE REDUCED COMPARED TO THE PAST
FEW DAYS DUE TO SOME DRIER AIR FILTERING IN ACROSS THE AREA ON THE
BACK-SIDE OF AN UPPER TROUGH...LIGHT WESTERLY LOW-LEVEL FLOW
COMBINED WITH A SUFFICIENT AMOUNT OF MOISTURE AND DAYTIME HEATING
WILL BE ENOUGH TO TRIGGER AFTERNOON SHRA/TSTMS TODAY. THE BEST CHANCE
FOR THIS ISLTD/SCT ACTIVITY WILL FAVOR THE EAST COAST TAF SITES
THROUGH THE AFTERNOON/EARLY EVENING PERIODS. WILL KEEP THE VCTS IN
THIS TAF PACKAGE FOR THE EAST COAST SITES. THIS ACTIVITY WILL TREND
DOWN THROUGH THE EARLY/MID EVENING HOURS WITH ANOTHER QUIET NIGHT
ANTICIPATED TONIGHT INTO SATURDAY MORNING
AVIATION...BNB/AG
PREV DISCUSSION... /ISSUED 416 AM EDT FRI JUN 14 2013/
DISCUSSION...
ONLY A FEW SHOWERS REMAIN ACROSS THE ATLANTIC WATERS THIS MORNING
AND SHOULD REMAIN OFFSHORE. WEAK MID LEVEL TROUGH WILL CONTINUE TO
PUSH OFFSHORE THE ATLANTIC COAST THROUGH THE DAY. HOWEVER...ANOTHER
ROUND OF AFTERNOON SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS
THE AREA TODAY BEFORE A SHORT DRYING PERIOD THROUGH THE FIRST PART
OF THE WEEKEND. WEAK SOUTHWESTERLY FLOW WILL PREVAIL AGAIN THROUGH
THE DAY BUT SHOULD NOT BE STRONG ENOUGH TO OVERTAKE A DEVELOPING
EAST COAST SEA BREEZE. THIS SHOULD ALLOW SHOWERS AND THUNDERSTORMS
TO DEVELOP MAINLY ALONG THE EAST COASTAL AREAS AND LOCAL HIGH
RESOLUTION MODELS ARE DEPICTING THIS. BELIEVE GUIDANCE IS WAY TOO
LOW FOR POPS...SO KEPT 20 POP AREA WIDE WITH 30 POP ALONG THE EAST
COAST METRO AREAS.
AS THE MID LEVEL TROUGH MOVES OUT...THIS WILL ALLOW RIDGING TO BUILD
ACROSS THE AREA FROM THE GULF OF MEXICO WHICH WILL ALLOW A DRIER
AIR MASS TO PUSH INTO THE AREA FOR THE WEEKEND. STEERING FLOW WILL
STILL BE WEAK WHICH SHOULD ALLOW A SEA BREEZE TO SET UP. AS A
RESULT...COULD NOT RULE OUT A FEW ISOLATED THUNDERSTORMS MAINLY
ACROSS THE NORTHWEST INTERIOR DURING THE PEAK HEATING HOURS
SATURDAY AND SUNDAY.
MONDAY THROUGH MIDWEEK...EASTERLY FLOW WILL BECOME RE-ESTABLISHED
ACROSS THE SOUTH FLORIDA PENINSULA. AT THE SAME TIME...A TROPICAL
WAVE IS STILL EXPECTED TO PUSH WEST-NORTHWEST ACROSS THE YUCATAN
PENINSULA AND INTO THE BAY OF CAMPECHE. AS IT DOES...IT WILL ENHANCE
CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS SOUTH FLORIDA WITH THE
BEST CHANCES TUESDAY AFTERNOON.
SLIGHTLY DRIER AIR WILL THEN FILTER INTO THE AREA THROUGH THE
LATTER HALF OF THE WEEK AS WEAK RIDGING SETS UP ACROSS THE WESTERN
ATLANTIC BEHIND THE PASSING TROPICAL WAVE. HOWEVER...SLIGHT
CHANCES FOR AFTERNOON SHOWERS AND THUNDERSTORMS WILL STILL
PREVAIL. TEMPERATURES THROUGH THE UPCOMING WEEK ARE EXPECTED TO
RUN SLIGHTLY ABOVE NORMAL WITH MAXIMUM HEAT INDEX READINGS
APPROACHING 100 DEGREES ACROSS THE EAST COAST METRO AREAS.
AVIATION...
ALTHOUGH THE SHRA/TSTM COVERAGE WILL BE REDUCED COMPARED TO THE PAST
FEW DAYS DUE TO SOME DRIER AIR FILTERING IN ACROSS THE AREA ON THE
BACK-SIDE OF AN UPPER TROUGH...LIGHT WESTERLY LOW-LEVEL FLOW
COMBINED WITH A SUFFICIENT AMOUNT OF MOISTURE AND DAYTIME HEATING
WILL BE ENOUGH TO TRIGGER AFTERNOON SHRA/TSTMS TODAY. THE BEST CHANCE
FOR THIS ISLTD/SCT ACTIVITY WILL FAVOR THE EAST COAST TAF SITES
THROUGH THE AFTERNOON/EARLY EVENING PERIODS. WILL KEEP THE VCTS IN
THIS TAF PACKAGE FOR THE EAST COAST SITES. THIS ACTIVITY WILL TREND
DOWN THROUGH THE EARLY/MID EVENING HOURS WITH ANOTHER QUIET NIGHT
ANTICIPATED TONIGHT INTO SATURDAY MORNING.
MARINE...
MAINLY BENIGN MARINE CONDITIONS ARE EXPECTED ACROSS THE AREA
WATERS OUTSIDE OF SHOWERS AND THUNDERSTORMS AS WINDS REMAIN AT
AROUND 10 KNOTS OR LESS THROUGH SATURDAY. FOR SUNDAY INTO EARLY
NEXT WEEK, EASTERLY FLOW RETURNS WITH WINDS AROUND 10 TO 15 KNOTS
AND SEAS AROUND 3 FEET ACROSS THE ATLANTIC WATERS AS A TROPICAL
WAVE PASSES BY WELL TO THE SOUTH.
FIRE WEATHER...
SLIGHTLY DRIER AIR IS EXPECTED TO PUSH INTO THE SOUTH FLORIDA AREA
INTO THE WEEKEND. HOWEVER...MINIMUM RELATIVE HUMIDITY VALUES
SHOULD STILL REMAIN ABOVE CRITICAL THRESHOLDS AND REMAIN THAT WAY
THROUGH NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 87 74 89 78 / 30 10 10 10
FORT LAUDERDALE 89 76 89 80 / 30 10 10 10
MIAMI 90 76 90 78 / 30 10 10 10
NAPLES 87 75 90 76 / 20 - 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1042 AM CDT FRI JUN 14 2013
.DISCUSSION...
ISSUED 1041 AM CDT FRI JUN 14 2013
15Z SURFACE MAP PLACED A RIDGE AXIS FROM LK SUPERIOR SOUTH THROUGH
CENTRAL IL AND INTO THE LOWER MISSISSIPPI VALLEY. THIS PROVIDED
LIGHT WINDS ALONG WITH MOSTLY SUNNY SKIES AND MILD
TEMPS/DEWPOINTS. UPSTREAM CONVECTION OVER CENTRAL IA/NRN MO
DEVELOPED AHEAD OF SHORTWAVE IN EASTERN NEB WHICH WAS TOPPING THE
UPPER RIDGE. THIS COMPLEX OF STORMS WAS BEING MAINTAINED FROM THE
SOUTHWEST BY A HIGH THETA-E FEED OF MOISTURE-RICH AIR FROM EASTERN
KS. THIS ACTIVITY SHOULD TEND TO DIMINISH AS IT SHIFTS EAST THIS
AFTERNOON AWAY FROM BEST SUPPORT AND INTO DRIER AIR ASSOCIATED
WITH THE LINGERING RIDGE. MOST HI-RES GUIDANCE SUPPORTS THIS IDEA
WITH THE HRRR BEING A NOTABLE EXCEPTION...BRINGING SCATTERED T-STORMS
INTO WEST CENTRAL IL AFTER 21Z. WILL KEEP A DRY FORECAST ACROSS
THE WEST FOR NOW BUT MONITOR TRENDS FOR THE LATE AFTERNOON.
OTHERWISE...SKIES TO BE MOSTLY SUNNY OVER THE EAST WITH INCREASING
HIGH CLOUDS OVER THE WESTERN CWA. HIGHS ON TRACK TO BE A COUPLE
DEGREES COOLER THAN YESTERDAY DUE TO SHALLOWER MIXING DEPTH UNDER
RIDGE AND ASSOCIATED LIGHTER WIND REGIME.
25
&&
.AVIATION...
ISSUED 620 AM CDT FRI JUN 14 2013
LITTLE TO WORRY ABOUT THROUGH ABOUT MID EVENING...WITH MAINLY
INCREASING HIGH CLOUDS AND NORTHEAST WINDS GRADUALLY SWINGING
AROUND TO THE SOUTHEAST. MAIN CONCERN WILL BE WITH OVERNIGHT
STORM CHANCES...AS A CONVECTIVE COMPLEX FORMS ACROSS IOWA/
NORTHERN MISSOURI THIS EVENING AND MOVES SOUTHEAST. CURRENTLY
THINK THAT KPIA IS THE ONLY CENTRAL ILLINOIS TAF SITE TO HAVE A
DECENT SHOT OF TSRA AFTER 06Z...BUT HAVE INCLUDED VCTS AT
KBMI/KSPI LATE AS SOME OF THE MODELS HINT THE STORMS MAY MAKE IT
THAT FAR EAST BY SUNRISE. HOWEVER...THE BETTER CHANCES OF STORMS
OVER CENTRAL ILLINOIS APPEAR TO BE AFTER THE CURRENT TAF FORECAST
PERIOD.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 330 AM CDT FRI JUN 14 2013
SHORT TERM...TODAY THROUGH MONDAY NIGHT
WILL USE A BLEND OF THE 00Z MODELS FOR THIS FORECAST WITH ONE MORE
NICE DAY TODAY WITH PARTLY TO MOSTLY SUNNY SKIES THEN BECOMING MORE
UNSETTLED THIS WEEKEND INTO MON BEFORE DRIER AND COOLER WEATHER
RETURNS TUE/WED. MET AND MAV GUIDANCE TEMPS SIMILAR THROUGH SUNDAY
THOUGH DID GO A BIT WARMER FOR HIGHS TODAY SINCE TEMPS HAVE BEEN
RUNNING ABOVE GUIDANCE TEMPS PAST FEW DAYS AND EXPECTING A FAIR
AMOUNT OF SUNSHINE YET TODAY. SPC CONTINUES SLIGHT RISK OF SEVERE
STORMS IN DAY2 OUTLOOK FOR SAT NW HALF OF CWA AND WILL NEED TO
ADDRESS THIS.
1023 MB CANADIAN HIGH PRESSURE NORTH OF LAKE SUPERIOR OVER CENTRAL
ONTARIO WAS RIDGING SOUTHWARD INTO THE MS VALLEY AND PROVIDING
NEARLY CLEAR SKIES OVER CENTRAL AND EASTERN IL WITH A FEW PATCHES
OF HIGH CLOUDS OVER WEST CENTRAL IL. COOLER TEMPS WERE IN THE
UPPER 50S AND LOWER 60S WITH MORE COMFORTABLE DEWPOINTS IN THE LOW
TO MID 50S WITH LIGHT WINDS.
MODELS WEAKEN HIGH PRESSURE OVER CENTRAL ONTARIO SSE INTO LOWER MI
AND OHIO AT 1019 MB THIS EVENING AS UPPER LEVEL HEIGHTS RISE A BIT
OVER IL AS UPPER LEVEL TROF OVER THE ATLANTIC STATES PULLS FURTHER
AWAY FROM IL. SCATTERED CUMULUS CLOUDS TO DEVELOP BY MIDDAY WITH
INCREASING HIGH CLOUDS ESPECIALLY IL RIVER VALLEY WHERE SKIES
BECOME PARTLY SUNNY THIS AFTERNOON...AND MOSTLY SUNNY OVER EASTERN
IL. HIGHS GENERALLY IN THE LOWER 80S WITH AREAS FROM I-74 NE
CLOSER TO 80F AS ENE WINDS LESS THAN 10 MPH PREVAIL TODAY.
MOST AREAS SHOULD STAY DRY YET THIS EVENING WITH JUST SMALL
CHANCES OF SHOWERS AND THUNDERSTORMS MOVING INTO THE IL RIVER
VALLEY LATER THIS EVENING. THEN INCREASING CHANCES OF SHOWERS AND
THUNDERSTORMS OVERNIGHT FROM I-55 NW WITH LIKELY POPS NW OF THE IL
RIVER LATE TONIGHT. THIS DUE TO MCS TO RIDE OVER TOP OF UPPER
LEVEL RIDGE OVER THE EASTERN PLAINS AND MOVE FROM IA INTO
CENTRAL/NW IL OVERNIGHT INTO SAT MORNING. EASTERN AND SE IL SHOULD
STAY DRY THROUGH THE NIGHT. LOWS TONIGHT IN THE LOWER 60S AND COOLEST
OVER EAST CENTRAL IL. SPC KEEPS SLIGHT RISK OVER CENTRAL AND
WESTERN IA TONIGHT.
BETTER CHANCES OF CONVECTION SAT OVER CENTRAL AND NORTHERN AREAS
WHILE JUST SLIGHT CHANCE IN SE IL SAT AFTERNOON. MCS TO WEAKEN
OVER CENTRAL IL SAT MORNING BUT SCATTERED THUNDERSTORMS TO
REDEVELOP IN UNSTABLE AIR MASS SAT AFTERNOON AND CONTINUE SAT NIGHT
WHEN YET ANOTHER MCS TO IMPACT PARTS OF CENTRAL/NORTHERN IL. SPC
HAS SLIGHT CHANCE FROM RANTOUL TO SPRINGFIELD NW LATER SAT AFTERNOON
AND SAT NIGHT WITH 15% RISK OF DAMAGING WIND GUSTS AND LARGE HAIL
POSSIBLE.
FRONTAL BOUNDARY TO PUSH SOUTHWARD THROUGH CENTRAL/SE IL SUNDAY
AND STALL FOR A TIME EARLY NEXT WEEK BEFORE PUSHING FURTHER SOUTH
LATER MON AND MON NIGHT. HAVE HIGHER CHANCES OF SHOWERS AND
THUNDERSTORMS OVER SOUTHERN HALF CWA SUNDAY INTO MONDAY. SPC HAS
5% RISK OF SEVERE STORMS ON SUNDAY OVER CENTRAL/SE IL. CONVECTION
CHANCES TO DIMINISH FROM NW TO SE LATER MON INTO MONDAY EVENING.
LONG TERM...TUESDAY THROUGH THURSDAY
CANADIAN HIGH PRESSURE SETTLING INTO THE GREAT LAKES REGION BY
TUE TO RETURN DRY AND COOLER AND LESS HUMID WEATHER TUE AND WED.
CONVECTION CHANCES RETURN TO THE MS VALLEY BY THU BUT MODELS
DIFFER ON TIMING OF RETURNING CONVECTION CHANCES TO IL AND STAYED
CLOSE TO ALLBLEND POPS WHICH ARE JUST SLIGHT OVER WESTERN AREAS
THU.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1039 AM CDT FRI JUN 14 2013
.UPDATE...
ISSUED AT 1033 AM CDT FRI JUN 14 2013
THUNDERSTORMS WERE OCCURRING IN SW IA AND NW MO ON THE NOSE OF A
LOW LEVEL JET AND STRONG MOISTURE GRADIENT...AND ON THE EDGE OF A
STRONG CAP. 850 MB DEWPOINT AT KTOP WAS +18C BUT DRIER AIR WAS NOTED
FARTHER TO THE NORTHEAST WITH KMPX -4C AND KDVN +7. THE BETTER
FORCING WILL REMAIN WEST AND SOUTHWEST OF THE DVN CWA BUT ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS WILL OCCUR IN OUR WESTERN
CWA LATE THIS MORNING INTO THE AFTERNOON HOURS.
UPDATE ISSUED AT 642 AM CDT FRI JUN 14 2013
RADAR SHOWS THE CONVECTION IN CENTRAL IOWA CONTINUES BUT IS
RAPIDLY WEAKENING AS IT MOVES INTO DRIER AIR AND AWAY FROM THE
BETTER SUPPORT. RAP TRENDS CONTINUE TO SHOW A WEAK BUT RESPECTABLE
THETA E GRADIENT WHICH IS HELPING TO MAINTAIN THE CONVECTION.
BASED ON RADAR AND RAP TRENDS SOME OF THIS CONVECTION WILL GET
INTO THE WESTERN CWFA THIS MORNING AS LIGHT SHOWERS OR SPRINKLES
BEFORE DISSIPATING.
WATER VAPOR AND THE RAP SHOW TWO VORT MAXES CURRENTLY MOVING
ACROSS NEBRASKA. THESE FEATURES WILL DRIVE THE DIURNAL CONVECTION
THIS AFTERNOON THAT WILL EVENTUALLY EVOLVE INTO ANOTHER NOCTURNAL
MCS LATE TONIGHT. ..08..
&&
.SYNOPSIS...
ISSUED AT 308 AM CDT FRI JUN 14 2013
06Z SFC ANALYSIS HAS A HIGH RUNNING FROM LAKE SUPERIOR INTO THE
LOWER MISSISSIPPI VALLEY. LOWS WERE IN SOUTHEAST MONTANA AND
SOUTHEAST COLORADO. THE MAIN SYNOPTIC FRONT RAN FROM SOUTHWEST
KANSAS INTO THE DEEP SOUTH. DEW POINTS WERE IN THE 60S AND 70S FROM
THE CENTRAL PLAINS INTO THE DEEP SOUTH WITH 40S AND 50S ACROSS THE
GREAT LAKES AND UPPER MISSISSIPPI VALLEY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 308 AM CDT FRI JUN 14 2013
THE MCS AND LIFT TOOLS INDICATE THE CURRENT CONVECTION FROM
SOUTHWEST MN INTO NORTHERN IOWA IS ASSOCIATED WITH A THETA E
GRADIENT AND VORT MAX. THIS CONVECTION WILL SLOWLY DISSIPATE AS IT
MOVES AWAY FROM THE BETTER MOISTURE AND INTO THE RIDGE. THUS THE
MORNING HOURS WILL BE DRY WITH AN INCREASE IN CLOUD COVER.
HOWEVER...THE CLOUD COVER WILL SLOWLY THIN AS IT HITS THE RIDGE SO
THERE SHOULD BE A RESPECTABLE AMOUNT OF SUNSHINE TO HELP WARM UP.
RAP TRENDS ALONG WITH THE MCS AND LIFT TOOLS INDICATE THE VORT MAX
MOVING THROUGH SOUTHERN NEBRASKA WILL PROBABLY BE THE MECHANISM TO
GENERATE DIURNAL CONVECTION THIS AFTERNOON. THIS CONVECTION SHOULD
DEVELOP OR MOVE INTO THE WESTERN CWFA AROUND MID AFTERNOON AND
SLOWLY OVERSPREAD THE WESTERN HALF OF THE CWFA THROUGH LATE
AFTERNOON.
TONIGHT...THE MCS AND LIFT TOOLS INDICATE THE DIURNAL CONVECTION IS
EXPECTED TO EVOLVE INTO ANOTHER NOCTURNAL MCS ACROSS THE AREA.
CONVECTION SHOULD REMAIN ISOLATED TO SCATTERED UNTIL CLOSER TO
MIDNIGHT WHEN THE LLJ VEERS INTO THE CWFA. AT THIS TIME UPSCALE
GROWTH AND AN INCREASE IN AREAL COVERAGE ACROSS THE CWFA WILL BE
SEEN. PWATS ARE EXPECTED TO BE OVER 1.5 INCHES SO THERE WOULD BE A
THREAT OF HEAVY RAIN IF STORMS MOVE OVER THE SAME AREA. THE GROUND
IS REASONABLY DRY SO THIS INITIAL ROUND OF RAIN SHOULD NOT CAUSE
MUCH IN THE WAY OF PROBLEMS. ..08..
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 308 AM CDT FRI JUN 14 2013
INITIAL FOCUS IS ON THUNDERSTORM POTENTIAL FOR SATURDAY THAT WILL
HAVE A RISK FOR BOTH SEVERE STORMS AND HEAVY RAINFALL. TRANSITION TO
NW FLOW TO THEN BRING COOLER AND DRIER WEATHER FOR AT LEAST THE
FIRST HALF OF NEXT WEEK.
NOCTURNAL MCS WILL LIKELY BE ON-GOING SATURDAY MORNING...WHERE
MODELS ARE IN GENERAL AGREEMENT DEPICTING LOW PRESSURE NEAR OMAHA
WITH A WARM...OR INITIALLY STATIONARY FRONT REACHING EAST ALONG THE
IA/MO BORDER. ALL ARE SUGGESTING A RIDGE TOPPING SHORTWAVE THAT WILL
PUSH THROUGH DURING THE DAY...WHICH SENDS THE SURFACE LOW
EAST-NORTHEAST ACROSS THE FORECAST AREA AND NUDGES THE SURFACE
BOUNDARY NORTHWARD. ON THE WARM SIDE OF THIS BOUNDARY...MODEL CAPES
ARE ROUGHLY IN THE RANGE OF 3500 TO OVER 4000 J/KG WITH BULK SHEAR
VALUES AROUND 40 TO 45 KTS...SUFFICIENT FOR SEVERE STORMS AND
SUPERCELLS ESPECIALLY ALONG THE BOUNDARY IN THE AFTERNOON INTO
EVENING. SPC HAS THE ENTIRE FORECAST AREA IN A SLIGHT RISK FOR DAY
2. MUCH WILL DEPEND ON THE TIMING OF THE EXITING OR DISSIPATING
OVERNIGHT MCS AND RELATED BOUNDARIES AND CLOUD COVER. FOR NOW...WILL
CONTINUE A BROAD-BRUSH APPROACH WITH LIKELY POPS FOR THUNDERSTORMS
OVER THE ENTIRE AREA. HIGHS WILL LIKELY BE LIMITED TO THE UPPER 70S
ACROSS THE NORTH...WHILE THE SOUTH SHOULD AT LEAST PUSH INTO THE 80S
WITH DEWPOINTS INTO THE 70S...DEPENDING ON TRENDS WITH CLOUD COVER AND
FRONTAL TIMING. ELEVATED SW FLOW OF 15 TO 30 KTS WILL ADVECT A HIGH
PW AIRMASS...AROUND 1.5 TO 1.8 OR 150 PERCENT OF NORMAL OVER THE
ENTIRE AREA...THAT WILL SUPPORT HEAVY RAINFALL IN HP TYPE SUPERCELLS OR
WHERE STORMS TRAIN ALONG BOUNDARIES. THE RESULTING FLASH FLOODING
THREAT WILL BE HIGHLY DEPENDENT ON RAINFALL COVERAGE AND AMOUNTS
FROM THE PREVIOUS EVENT. FOR NOW...HAVE WIDESPREAD QPF AMOUNTS OF A
QUARTER TO HALF INCH...BUT FULLY EXPECT STORM SCALE TOTALS OF 1 TO 2
INCHES.
SATURDAY NIGHT...A STRONGER SHORTWAVE...INITIALLY OVER THE TX BEND
REGION AT 00Z...IS SHOWN RIDING NORTH AND THEN SWEEPING EAST ACROSS
THE FORECAST AREA IN THE FIRST HALF OF THE NIGHT...PROVIDING RENEWED
FOCUS FOR LIKELY ANOTHER MCS AND POSSIBLE HEAVY RAINFALL AND LIKELY
POPS ARE MAINTAINED. THIS SYSTEM IS EXPECTED TO SUPPRESS THE FRONTAL
BOUNDARY BACK TO JUST SOUTH OF THE FORECAST AREA SUNDAY. THE CLOSE
PROXIMITY OF THIS BOUNDARY...AND A STRONG UPPER SHORTWAVE THEN
ADVANCING FROM THE NW WILL KEEP SHOWERS AND THUNDERSTORMS IN THE
FORECAST THROUGH MONDAY...BUT THE HEAVY RAINFALL THREAT WILL BE
DIMINISHED. A NW FLOW AND HIGH PRESSURE THEN SUGGESTS DRY CONDITIONS
THROUGH AT LEAST WED WITH NEAR TO SLIGHTLY BELOW NORMAL
TEMPERATURES. MODEL CONSENSUS HAS CHANCES FOR SHOWERS AND
THUNDERSTORMS RETURNING TO THE FORECAST THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 642 AM CDT FRI JUN 14 2013
CONVECTION IN CENTRAL IOWA WILL DISSIPATE THROUGH 18Z/14 AS IT
ENCOUNTERS DRIER AIR OVER EASTERN IOWA. VFR WX IS EXPECTED
THROUGH 00Z/15. TSRA WILL DEVELOP AFT 20Z/14 THAT WILL BECOME MORE
NUMEROUS ACROSS EASTERN IOWA/NORTHERN ILLINOIS AFT 00Z/15. AFT
00Z/15 VFR WX IS EXPECTED TO CONTINUE. HOWEVER...THE TSRA ARE
EXPECTED TO EVOLVE INTO A TSRA COMPLEX THAT MAY RESULT IN MVFR
CONDITIONS AFT 06Z/15. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...08
SHORT TERM...08
LONG TERM...SHEETS
AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
656 AM CDT FRI JUN 14 2013
.UPDATE...
ISSUED AT 642 AM CDT FRI JUN 14 2013
RADAR SHOWS THE CONVECTION IN CENTRAL IOWA CONTINUES BUT IS
RAPIDLY WEAKENING AS IT MOVES INTO DRIER AIR AND AWAY FROM THE
BETTER SUPPORT. RAP TRENDS CONTINUE TO SHOW A WEAK BUT RESPECTABLE
THETA E GRADIENT WHICH IS HELPING TO MAINTAIN THE CONVECTION.
BASED ON RADAR AND RAP TRENDS SOME OF THIS CONVECTION WILL GET
INTO THE WESTERN CWFA THIS MORNING AS LIGHT SHOWERS OR SPRINKLES
BEFORE DISSIPATING.
WATER VAPOR AND THE RAP SHOW TWO VORT MAXES CURRENTLY MOVING
ACROSS NEBRASKA. THESE FEATURES WILL DRIVE THE DIURNAL CONVECTION
THIS AFTERNOON THAT WILL EVENTUALLY EVOLVE INTO ANOTHER NOCTURNAL
MCS LATE TONIGHT. ..08..
&&
.SYNOPSIS...
ISSUED AT 308 AM CDT FRI JUN 14 2013
06Z SFC ANALYSIS HAS A HIGH RUNNING FROM LAKE SUPERIOR INTO THE
LOWER MISSISSIPPI VALLEY. LOWS WERE IN SOUTHEAST MONTANA AND
SOUTHEAST COLORADO. THE MAIN SYNOPTIC FRONT RAN FROM SOUTHWEST
KANSAS INTO THE DEEP SOUTH. DEW POINTS WERE IN THE 60S AND 70S FROM
THE CENTRAL PLAINS INTO THE DEEP SOUTH WITH 40S AND 50S ACROSS THE
GREAT LAKES AND UPPER MISSISSIPPI VALLEY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 308 AM CDT FRI JUN 14 2013
THE MCS AND LIFT TOOLS INDICATE THE CURRENT CONVECTION FROM
SOUTHWEST MN INTO NORTHERN IOWA IS ASSOCIATED WITH A THETA E
GRADIENT AND VORT MAX. THIS CONVECTION WILL SLOWLY DISSIPATE AS IT
MOVES AWAY FROM THE BETTER MOISTURE AND INTO THE RIDGE. THUS THE
MORNING HOURS WILL BE DRY WITH AN INCREASE IN CLOUD COVER.
HOWEVER...THE CLOUD COVER WILL SLOWLY THIN AS IT HITS THE RIDGE SO
THERE SHOULD BE A RESPECTABLE AMOUNT OF SUNSHINE TO HELP WARM UP.
RAP TRENDS ALONG WITH THE MCS AND LIFT TOOLS INDICATE THE VORT MAX
MOVING THROUGH SOUTHERN NEBRASKA WILL PROBABLY BE THE MECHANISM TO
GENERATE DIURNAL CONVECTION THIS AFTERNOON. THIS CONVECTION SHOULD
DEVELOP OR MOVE INTO THE WESTERN CWFA AROUND MID AFTERNOON AND
SLOWLY OVERSPREAD THE WESTERN HALF OF THE CWFA THROUGH LATE
AFTERNOON.
TONIGHT...THE MCS AND LIFT TOOLS INDICATE THE DIURNAL CONVECTION IS
EXPECTED TO EVOLVE INTO ANOTHER NOCTURNAL MCS ACROSS THE AREA.
CONVECTION SHOULD REMAIN ISOLATED TO SCATTERED UNTIL CLOSER TO
MIDNIGHT WHEN THE LLJ VEERS INTO THE CWFA. AT THIS TIME UPSCALE
GROWTH AND AN INCREASE IN AREAL COVERAGE ACROSS THE CWFA WILL BE
SEEN. PWATS ARE EXPECTED TO BE OVER 1.5 INCHES SO THERE WOULD BE A
THREAT OF HEAVY RAIN IF STORMS MOVE OVER THE SAME AREA. THE GROUND
IS REASONABLY DRY SO THIS INITIAL ROUND OF RAIN SHOULD NOT CAUSE
MUCH IN THE WAY OF PROBLEMS. ..08..
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 308 AM CDT FRI JUN 14 2013
INITIAL FOCUS IS ON THUNDERSTORM POTENTIAL FOR SATURDAY THAT WILL
HAVE A RISK FOR BOTH SEVERE STORMS AND HEAVY RAINFALL. TRANSITION TO
NW FLOW TO THEN BRING COOLER AND DRIER WEATHER FOR AT LEAST THE
FIRST HALF OF NEXT WEEK.
NOCTURNAL MCS WILL LIKELY BE ON-GOING SATURDAY MORNING...WHERE
MODELS ARE IN GENERAL AGREEMENT DEPICTING LOW PRESSURE NEAR OMAHA
WITH A WARM...OR INITIALLY STATIONARY FRONT REACHING EAST ALONG THE
IA/MO BORDER. ALL ARE SUGGESTING A RIDGE TOPPING SHORTWAVE THAT WILL
PUSH THROUGH DURING THE DAY...WHICH SENDS THE SURFACE LOW
EAST-NORTHEAST ACROSS THE FORECAST AREA AND NUDGES THE SURFACE
BOUNDARY NORTHWARD. ON THE WARM SIDE OF THIS BOUNDARY...MODEL CAPES
ARE ROUGHLY IN THE RANGE OF 3500 TO OVER 4000 J/KG WITH BULK SHEAR
VALUES AROUND 40 TO 45 KTS...SUFFICIENT FOR SEVERE STORMS AND
SUPERCELLS ESPECIALLY ALONG THE BOUNDARY IN THE AFTERNOON INTO
EVENING. SPC HAS THE ENTIRE FORECAST AREA IN A SLIGHT RISK FOR DAY
2. MUCH WILL DEPEND ON THE TIMING OF THE EXITING OR DISSIPATING
OVERNIGHT MCS AND RELATED BOUNDARIES AND CLOUD COVER. FOR NOW...WILL
CONTINUE A BROAD-BRUSH APPROACH WITH LIKELY POPS FOR THUNDERSTORMS
OVER THE ENTIRE AREA. HIGHS WILL LIKELY BE LIMITED TO THE UPPER 70S
ACROSS THE NORTH...WHILE THE SOUTH SHOULD AT LEAST PUSH INTO THE 80S
WITH DEWPOINTS INTO THE 70S...DEPENDING ON TRENDS WITH CLOUD COVER AND
FRONTAL TIMING. ELEVATED SW FLOW OF 15 TO 30 KTS WILL ADVECT A HIGH
PW AIRMASS...AROUND 1.5 TO 1.8 OR 150 PERCENT OF NORMAL OVER THE
ENTIRE AREA...THAT WILL SUPPORT HEAVY RAINFALL IN HP TYPE SUPERCELLS OR
WHERE STORMS TRAIN ALONG BOUNDARIES. THE RESULTING FLASH FLOODING
THREAT WILL BE HIGHLY DEPENDENT ON RAINFALL COVERAGE AND AMOUNTS
FROM THE PREVIOUS EVENT. FOR NOW...HAVE WIDESPREAD QPF AMOUNTS OF A
QUARTER TO HALF INCH...BUT FULLY EXPECT STORM SCALE TOTALS OF 1 TO 2
INCHES.
SATURDAY NIGHT...A STRONGER SHORTWAVE...INITIALLY OVER THE TX BEND
REGION AT 00Z...IS SHOWN RIDING NORTH AND THEN SWEEPING EAST ACROSS
THE FORECAST AREA IN THE FIRST HALF OF THE NIGHT...PROVIDING RENEWED
FOCUS FOR LIKELY ANOTHER MCS AND POSSIBLE HEAVY RAINFALL AND LIKELY
POPS ARE MAINTAINED. THIS SYSTEM IS EXPECTED TO SUPPRESS THE FRONTAL
BOUNDARY BACK TO JUST SOUTH OF THE FORECAST AREA SUNDAY. THE CLOSE
PROXIMITY OF THIS BOUNDARY...AND A STRONG UPPER SHORTWAVE THEN
ADVANCING FROM THE NW WILL KEEP SHOWERS AND THUNDERSTORMS IN THE
FORECAST THROUGH MONDAY...BUT THE HEAVY RAINFALL THREAT WILL BE
DIMINISHED. A NW FLOW AND HIGH PRESSURE THEN SUGGESTS DRY CONDITIONS
THROUGH AT LEAST WED WITH NEAR TO SLIGHTLY BELOW NORMAL
TEMPERATURES. MODEL CONSENSUS HAS CHANCES FOR SHOWERS AND
THUNDERSTORMS RETURNING TO THE FORECAST THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 642 AM CDT FRI JUN 14 2013
CONVECTION IN CENTRAL IOWA WILL DISSIPATE THROUGH 18Z/14 AS IT
ENCOUNTERS DRIER AIR OVER EASTERN IOWA. VFR WX IS EXPECTED
THROUGH 00Z/15. TSRA WILL DEVELOP AFT 20Z/14 THAT WILL BECOME MORE
NUMEROUS ACROSS EASTERN IOWA/NORTHERN ILLINOIS AFT 00Z/15. AFT
00Z/15 VFR WX IS EXPECTED TO CONTINUE. HOWEVER...THE TSRA ARE
EXPECTED TO EVOLVE INTO A TSRA COMPLEX THAT MAY RESULT IN MVFR
CONDITIONS AFT 06Z/15. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...08
SHORT TERM...08
LONG TERM...SHEETS
AVIATION...08
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
930 AM MDT Fri Jun 14 2013
.UPDATE...
Current satellite imagery shows upper level trof extending from
northern Alberta to southern Idaho with the trof axis slightly east
of the Rocky Mtn Front. Moisture plume along/behind the trof axis
will bring one more round of showers and isolated to scattered
thunderstorms over central and southwest MT this aftn. Have slightly
increased chances of precipitation from Great Falls north to US/Can
border for today as morning model runs indicating enough lift and
instability there to promote better precip coverage. Although
severe storms are not expected for our region, will be keeping a
close eye on storm development as cooling aloft may bring slightly
higher chance for some storms to produce small hail. Gradual
clearing still expected this evening with dry/warmer conditions
beginning tomorrow.
Waranauskas
&&
.DISCUSSION...
Today through Sunday night...One more day of unsettled weather is in
store for the area. An upper level trof will move across the area
today bringing additional instability. A jet max rounding the upper
trof will aid in the development of showers and thunderstorms over
southwest Montana this morning. Both the models and HRRR analysis
indicate the development of storms over the southwest mountains this
morning and their subsequent movement north and east during the
afternoon. SPC has the entire county warning area under a general
thunderstorm outlook for today. Some storms may be strong but
widespread severe storms are not anticipated. Breezy westerly winds
will develop across the plains by late morning. Cooler air has moved
into southwest Montana and some snow is possible above 7500 feet
today. Convective activity ends by late afternoon with rising
heights as an upper ridge begins to build over western Montana.
Saturday and Sunday will be dry with warming temperatures. Afternoon
readings will be below seasonal averages today but warm to near to
slightly above seasonal averages this weekend. Emanuel
Sunday night through Friday...Models continue to be in good
agreement, but the overall progression of next week`s low pressure
system from the Pacific Ocean is about 24 hours slower than the
previous runs. Will address the changes below. An upper level ridge
of high pressure will linger over Montana through Monday night. The
airmass will warm to between 5 and 10 degrees above seasonal
averages, but weak steering winds aloft will keep the threat for
isolated thunderstorm activity over the higher terrain. The
aforementioned weather system will then deepen and move onto the
Pacific coast on Tuesday. The increasingly moist and unstable
southwesterly flow aloft ahead of the system will bring an
increasing chance of showers and thunderstorms mainly to the western
half of Montana. The flow aloft will also pump warmer air into the
area, causing temperatures to warm to between 10 and 15 degrees
above normal. As the system moves into the Pacific Northwest on
Wednesday, the flow aloft will become more southerly, unstable, and
diffluent. This, in turn, will bring a much better chance for
showers and thunderstorms to the area, especially over north
central/central Montana. Forecast CAPE values increase to between
1000 and 2000 J/kg Wednesday afternoon/evening, which hints at the
potential for a round of strong to possibly severe thunderstorms.
Would like to see run-to-run consistency with this feature before
mentioning severe potential in Hazardous Weather Outlook. Forecast
models differ with exact movement of this system beyond Wednesday.
GFS model moves the system into southern Alberta and Saskatchewan by
Friday, while the ECMWF model keeps the system over the Pacific
Northwest. The GEM is slow with movement of the system (moving it
over Montana), but it weakens the system. With this discrepancy,
have kept the chance for showers/thunderstorms near climatology and
will look to refine the details when the models come into better
agreement. Regardless, the models all bring a cold front through the
area Wednesday night, which should cool temperatures back to between
5 and 10 degrees below normal for Thursday through Friday and bring
breezy westerly winds to the area. Coulston
&&
.AVIATION...
Updated 1155Z.
VFR conditions are generally expected across north central, central,
and southwest Montana through at least Friday night, unless
otherwise noted. An upper level trough of low pressure will lift
northeast out of the area through the period. A disturbance within
this trough will continue rain/mountain snow showers across
southwest Montana through around 17Z, possibly causing conditions to
lower to MVFR at times at KBZN in heavier showers. Otherwise, winds
aloft will become more breezy and westerly by 18Z as the trough
moves northeast. Mid level moisture will combine with weakly
unstable airmass after 18Z. The best chance for showers and
thunderstorms will be over the mountain areas, as the westerly
downslope winds (possibly gusting over 30 kt at times) will limit
the threat over the plains. However, am thinking the likelihood that
thunderstorms will directly impact any given terminal is low, so
have not included mention of them in the TAFs. Skies will clear and
winds will decrease after 01Z as the trough exits the area.
Coulston
&&
.HYDROLOGY...
Point flood warnings remain in effect for the Big Sandy Creek near
Havre and Clear Creek near Chinook. Rain from recent thunderstorms
will keep water levels high in many creeks and streams. Drier
weather this weekend should result in gradually decreasing levels
into early next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 64 42 75 44 / 20 10 0 0
CTB 63 42 73 43 / 20 10 0 10
HLN 64 43 75 46 / 40 10 0 0
BZN 61 38 75 41 / 70 20 0 0
WEY 55 31 68 34 / 40 10 0 0
DLN 59 36 73 41 / 70 20 0 0
HVR 68 46 76 48 / 20 20 10 10
LWT 62 41 71 44 / 30 10 0 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
Flood Warnings continue until further notice for Big Sandy Creek
near Havre and Clear Creek near Chinook.
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
555 AM MDT Fri Jun 14 2013
UPDATE TO AVIATION
.DISCUSSION...
Today through Sunday night...One more day of unsettled weather is in
store for the area. An upper level trof will move across the area
today bringing additional instability. A jet max rounding the upper
trof will aid in the development of showers and thunderstorms over
southwest Montana this morning. Both the models and HRRR analysis
indicate the development of storms over the southwest mountains this
morning and their subsequent movement north and east during the
afternoon. SPC has the entire county warning area under a general
thunderstorm outlook for today. Some storms may be strong but
widespread severe storms are not anticipated. Breezy westerly winds
will develop across the plains by late morning. Cooler air has moved
into southwest Montana and some snow is possible above 7500 feet
today. Convective activity ends by late afternoon with rising
heights as an upper ridge begins to build over western Montana.
Saturday and Sunday will be dry with warming temperatures. Afternoon
readings will be below seasonal averages today but warm to near to
slightly above seasonal averages this weekend. Emanuel
Sunday night through Friday...Models continue to be in good
agreement, but the overall progression of next week`s low pressure
system from the Pacific Ocean is about 24 hours slower than the
previous runs. Will address the changes below. An upper level ridge
of high pressure will linger over Montana through Monday night. The
airmass will warm to between 5 and 10 degrees above seasonal
averages, but weak steering winds aloft will keep the threat for
isolated thunderstorm activity over the higher terrain. The
aforementioned weather system will then deepen and move onto the
Pacific coast on Tuesday. The increasingly moist and unstable
southwesterly flow aloft ahead of the system will bring an
increasing chance of showers and thunderstorms mainly to the western
half of Montana. The flow aloft will also pump warmer air into the
area, causing temperatures to warm to between 10 and 15 degrees
above normal. As the system moves into the Pacific Northwest on
Wednesday, the flow aloft will become more southerly, unstable, and
diffluent. This, in turn, will bring a much better chance for
showers and thunderstorms to the area, especially over north
central/central Montana. Forecast CAPE values increase to between
1000 and 2000 J/kg Wednesday afternoon/evening, which hints at the
potential for a round of strong to possibly severe thunderstorms.
Would like to see run-to-run consistency with this feature before
mentioning severe potential in Hazardous Weather Outlook. Forecast
models differ with exact movement of this system beyond Wednesday.
GFS model moves the system into southern Alberta and Saskatchewan by
Friday, while the ECMWF model keeps the system over the Pacific
Northwest. The GEM is slow with movement of the system (moving it
over Montana), but it weakens the system. With this discrepancy,
have kept the chance for showers/thunderstorms near climatology and
will look to refine the details when the models come into better
agreement. Regardless, the models all bring a cold front through the
area Wednesday night, which should cool temperatures back to between
5 and 10 degrees below normal for Thursday through Friday and bring
breezy westerly winds to the area. Coulston
&&
.AVIATION...
Updated 1155Z.
VFR conditions are generally expected across north central, central,
and southwest Montana through at least Friday night, unless
otherwise noted. An upper level trough of low pressure will lift
northeast out of the area through the period. A disturbance within
this trough will continue rain/mountain snow showers across
southwest Montana through around 17Z, possibly causing conditions to
lower to MVFR at times at KBZN in heavier showers. Otherwise, winds
aloft will become more breezy and westerly by 18Z as the trough
moves northeast. Mid level moisture will combine with weakly
unstable airmass after 18Z. The best chance for showers and
thunderstorms will be over the mountain areas, as the westerly
downslope winds (possibly gusting over 30 kt at times) will limit
the threat over the plains. However, am thinking the likelihood that
thunderstorms will directly impact any given terminal is low, so
have not included mention of them in the TAFs. Skies will clear and
winds will decrease after 01Z as the trough exits the area.
Coulston
&&
.HYDROLOGY...
Point flood warnings remain in effect for the Big Sandy Creek near
Havre and Clear Creek near Chinook. Rain from recent thunderstorms
will keep water levels high in many creeks and streams. Drier
weather this weekend should result in gradually decreasing levels
into early next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 64 42 75 44 / 20 10 0 0
CTB 63 42 73 43 / 20 10 0 10
HLN 64 43 75 46 / 40 10 0 0
BZN 61 38 75 41 / 70 20 0 0
WEY 55 31 68 34 / 40 10 0 0
DLN 59 36 73 41 / 70 20 0 0
HVR 68 46 76 48 / 20 20 10 10
LWT 62 41 71 44 / 30 10 0 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
Flood Warnings continue until further notice for Big Sandy Creek
near Havre and Clear Creek near Chinook.
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
415 AM MDT Fri Jun 14 2013
.DISCUSSION...
Today through Sunday night...One more day of unsettled weather is in
store for the area. An upper level trof will move across the area
today bringing additional instability. A jet max rounding the upper
trof will aid in the development of showers and thunderstorms over
southwest Montana this morning. Both the models and HRRR analysis
indicate the development of storms over the southwest mountains this
morning and their subsequent movement north and east during the
afternoon. SPC has the entire county warning area under a general
thunderstorm outlook for today. Some storms may be strong but
widespread severe storms are not anticipated. Breezy westerly winds
will develop across the plains by late morning. Cooler air has moved
into southwest Montana and some snow is possible above 7500 feet
today. Convective activity ends by late afternoon with rising
heights as an upper ridge begins to build over western Montana.
Saturday and Sunday will be dry with warming temperatures. Afternoon
readings will be below seasonal averages today but warm to near to
slightly above seasonal averages this weekend. Emanuel
Sunday night through Friday...Models continue to be in good
agreement, but the overall progression of next week`s low pressure
system from the Pacific Ocean is about 24 hours slower than the
previous runs. Will address the changes below. An upper level ridge
of high pressure will linger over Montana through Monday night. The
airmass will warm to between 5 and 10 degrees above seasonal
averages, but weak steering winds aloft will keep the threat for
isolated thunderstorm activity over the higher terrain. The
aforementioned weather system will then deepen and move onto the
Pacific coast on Tuesday. The increasingly moist and unstable
southwesterly flow aloft ahead of the system will bring an
increasing chance of showers and thunderstorms mainly to the western
half of Montana. The flow aloft will also pump warmer air into the
area, causing temperatures to warm to between 10 and 15 degrees
above normal. As the system moves into the Pacific Northwest on
Wednesday, the flow aloft will become more southerly, unstable, and
diffluent. This, in turn, will bring a much better chance for
showers and thunderstorms to the area, especially over north
central/central Montana. Forecast CAPE values increase to between
1000 and 2000 J/kg Wednesday afternoon/evening, which hints at the
potential for a round of strong to possibly severe thunderstorms.
Would like to see run-to-run consistency with this feature before
mentioning severe potential in Hazardous Weather Outlook. Forecast
models differ with exact movement of this system beyond Wednesday.
GFS model moves the system into southern Alberta and Saskatchewan by
Friday, while the ECMWF model keeps the system over the Pacific
Northwest. The GEM is slow with movement of the system (moving it
over Montana), but it weakens the system. With this discrepancy,
have kept the chance for showers/thunderstorms near climatology and
will look to refine the details when the models come into better
agreement. Regardless, the models all bring a cold front through the
area Wednesday night, which should cool temperatures back to between
5 and 10 degrees below normal for Thursday through Friday and bring
breezy westerly winds to the area. Coulston
&&
.AVIATION...
Updated 0430Z.
A deep trough of low pressure will continue to influence the weather
across the region tonight. Showers will push out of the area by 08Z
with conditions at KLWT and KBZN improving to VFR. Another round of
showers will affect KBZN after 10Z bringing VFR and possibly IFR
conditions through the mid-morning. Skies will begin to clear by
late morning across the area and KBZN should improve to VFR. Breezy
westerly winds will develop late morning over the plains and spread
into the valleys in the afternoon. Wind gusts will reach up to 35
knots in the plains. Expect winds to diminish Friday evening.
Langlieb
&&
.HYDROLOGY...
Point flood warnings remain in effect for the Big Sandy Creek near
Havre and Clear Creek near Chinook. Rain from recent thunderstorms
will keep water levels high in many creeks and streams. Drier
weather this weekend should result in gradually decreasing levels
into early next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 64 42 75 44 / 20 10 0 0
CTB 63 42 73 43 / 20 10 0 10
HLN 64 43 75 46 / 40 10 0 0
BZN 61 38 75 41 / 70 20 0 0
WEY 55 31 68 34 / 40 10 0 0
DLN 59 36 73 41 / 70 20 0 0
HVR 68 46 76 48 / 20 20 10 10
LWT 62 41 71 44 / 30 10 0 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
Flood Warnings continue until further notice for Big Sandy Creek
near Havre and Clear Creek near Chinook.
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS HASTINGS NE
953 AM CDT FRI JUN 14 2013
.UPDATE...
ISSUED AT 952 AM CDT FRI JUN 14 2013
OFF TO A BIT OF SLOW START DUE TO MONITORING RADAR THRU 830 AM.
THERE WERE A COUPLE OF NEAR-SVR STORMS THAT TRACKED FROM NEAR
HANSEN E ALONG THE HAMILTON-CLAY COUNTY LINE. WE SAW 50 DBZ UP TO
32K FT.
THE MRNG SHWRS/TSTMS WERE WARM FRONT GENERATED. THE HEAT WILL NOW
FOLLOW.
FCST HOURLY TEMPS WERE RUNNING WAY TOO WARM IN THE RAIN-COOLED
AREAS. SO SOME MAJOR ADJUSTMENTS HAVE BEEN MADE. CLEARING IS
HEADING E PER VIS SAT SO TEMPS SHOULD ROCKET UP. ALSO ADJUSTED
POPS AS SHWRS/TSTMS HAVE NEARLY CLEARED THE FCST AREA. POPS WERE
ALSO BLENDED WITH MULTIPLE HI-RES MODELS FROM 23Z-06Z TO COVER
TSTMS EXPECTED TO ERUPT.
FURTHER EVALUATION OF THE SITUATION WILL BE ON-GOING AND WE`LL
PROBABLY HAVE MORE IN AN AFD LATER THIS MRNG. 12Z SOUNDINGS ARE
SURPRISINGLY MOIST UP TO 850 MB. HOWEVER...WITH HIGHS OF 94-104F
AT 5 PM...SFC TEMP/DWPT SPREADS WILL STILL RESULT IN SUBSTANTIAL
DRYING BELOW CLOUD BASES THAT DEVELOP.
BASED ON BEST-VERIFYING HIGH TEMP GUIDANCE WE WILL PROBABLY BE
RAISING HIGH TEMPS SEVERAL DEGS IN THE TRI-CITIES AREA PENDING
FURTHER EVALUATION BEFORE NOON.
SLGT RISK CONTINUES FOR LATE THIS AFTN-EVNG.
PLEASE FOLLOW LATEST UPDATES FROM THE SPC VIA THEIR OUTLOOKS AND
MESOSCALE DISCUSSIONS...AND ALL FUTURE STATEMENTS/WATCHES/WARNINGS
FROM THIS OFFICE.
SKYWARN: BE ALERT FOR ACTIVATION IN THE 21Z-00Z TIME FRAME.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 413 AM CDT FRI JUN 14 2013
THE PRIMARY FORECAST CONCERN CENTERS AROUND THE CHANCE OF
THUNDERSTORMS EARLY THIS MORNING AND THEN AGAIN LATER THIS
AFTERNOON. SOME THUNDERSTORMS LATE THIS AFTERNOON AND EVENING WILL
LIKELY BE SEVERE.
THE FIRST ROUND OF THUNDERSTORMS HAVE BEEN WEAKENING AS THEY TRACK
EAST. THE HRRR SEEMS TO HAVE A GOOD HANDLE ON THESE STORMS AND
TRACKS THEM ALL THE WAY ACROSS OUR FORECAST AREA GENERALLY ALONG
THE INTERSTATE 80/HWY 6 CORRIDOR. CURRENT EXPECTATION IS THAT ALL
OF THESE THUNDERSTORMS WILL HAVE EITHER DECAYED OR BE EAST OF OUR
FORECAST AREA BY MID MORNING WITH DRY CONDITIONS FROM LATE
MORNING THROUGH MID AFTERNOON. THE HIGH CIRRUS LEFT OVER FROM THE
MORNING THUNDERSTORMS WILL THIN AND WE SHOULD SEE A GOOD DEAL OF
SUNSHINE TODAY HELPING TEMPERATURES SKY ROCKET. AN INCREASING
SOUTH WIND IN THE WARM SECTOR TODAY...WHICH WILL INCLUDE ALL OF
OUR FORECAST AREA EXCEPT MAYBE OUR FAR NORTHERN ZONES WILL ALSO
HELP TO GIVE TEMPERATURES A BOOST. EXPECT AFTERNOON HIGHS TO RANGE
FROM AROUND 90 IN OUR FAR NORTH AROUND ORD TO OVER 100 ACROSS MUCH
OF NORTH CENTRAL KANSAS.
THERE IS GOOD FORECAST MODEL AGREEMENT THAT AFTERNOON
THUNDERSTORMS WILL EVENTUALLY OVERCOME AN ELEVATED CAP
AND INITIATE ALONG A SFC FRONT THAT WILL STRETCH FROM NORTHEAST
NEBRASKA INTO SOUTH CENTRAL NEBRASKA AND NORTHWEST KANSAS. MLCAPE
VALUES ALONG THE FRONT WILL RANGE FROM 2000 TO 4000 J/KG MAKING
FOR A VERY UNSTABLE ATMOSPHERE. 0-6KM WIND SHEAR WILL BE MORE
MARGINAL AT 25 TO 35 KTS. THE COMBINATION OF STRONG
INSTABILITY...AT LEAST MARGINAL SHEAR...AND A FRONTAL BOUNDARY
SHOULD BE MORE THAN SUFFICIENT TO ALLOW FOR SEVERAL SEVERE
THUNDERSTORMS ACROSS OUR FORECAST AREA LATE THIS AFTERNOON AND
EVENING. EXPECT INITIATION WILL LIKELY BE AFTER 4 PM WITH THE
GREATEST SEVERE WEATHER THREAT IN THE 5 PM TO 10 PM TIME FRAME.
REDEVELOPMENT AND POSSIBLE TRAINING OF THUNDERSTORMS ALONG THE
FRONT WILL BE POSSIBLE LEADING TO LOCALIZED HEAVY RAIN. THE
HIGHEST CHANCE OF THUNDERSTORMS WILL GENERALLY BE NEAR HIGHWAY 30
FROM MERRICK COUNTY DOWN INTO GRAND ISLAND AND KEARNEY...AND THEN
SOUTHWEST INTO GOSPER AND FURNAS COUNTY. THE CHANCE OF
THUNDERSTORMS WILL DECREASE PRETTY FAST AS YOU HEAD SOUTHEAST OF
THIS CORRIDOR INTO NORTH CENTRAL KANSAS. THE PRIMARY SEVERE
WEATHER THREATS WILL BE LARGE HAIL TO THE SIZE OF GOLFBALLS AND
WIND GUSTS TO 70 MPH. WIND IS A BIG CONCERN DUE TO THE INVERTED V
FORECAST SOUNDING AND STEEP LAPSE RATES ALONG WITH THE OBVIOUSLY
HIGH CAPE. THE TORNADO THREAT WILL BE LIMITED DUE TO GENERALLY
WEAK LOW LEVEL SHEAR AND HIGHER LCL HEIGHTS. THE LIMITED TORNADO
THREAT WILL BE ACROSS OUR NORTHEASTERN CWA PRIMARY FOR THE KEARNEY
AND GRAND ISLAND AREAS AND POINTS NORTHEAST WHERE LCL HEIGHTS WILL
BE THE LOWEST AND THERE MIGHT BE SOME BACKING OF THE SFC WIND BY
EARLY EVENING...BUT AGAIN THIS IS ONLY A LIMITED THREAT WITH THE
PRIMARY THREATS TODAY BEING BIG HAIL AND STRONG THUNDERSTORM
WINDS.
THE CONVECTION WILL SLOWLY PUSH EAST TONIGHT AND AREAS ALONG AND
NORTH OF HIGHWAY 6 MAY ALSO SEE SOME ADDITIONAL THUNDERSTORM
REDEVELOPMENT DURING THE LATE EVENING HOURS AS THE LOW LEVEL JET
STRENGTHENS AND NOSES INTO OUR NEBRASKA ZONES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 413 AM CDT FRI JUN 14 2013
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
AN ACTIVE WEATHER PATTERN WILL BE FOUND ACROSS THE AREA THROUGH THIS
PERIOD. MODELS ARE SIMILAR IN THE MAIN FEATURES WITH SUBTLE
DIFFERENCES IN THE FINER DETAILS. SEVERAL UPPER LEVEL LOWS MOVE
THROUGH THE AREA DURING THE PERIOD AND EACH HAS THE POTENTIAL FOR
SOME THUNDERSTORMS. WITH THIS IN MIND THERE ARE CHANCES FOR
THUNDERSTORMS NEARLY EVERY PERIOD FOR PORTIONS OF THE AREA.
THE FIRST UPPER LEVEL LOW MOVES THROUGH THE AREA SATURDAY.
THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG A NEARLY STATIONARY
FRONT. THE QUESTION IS WHERE THIS FRONT WILL BE AND WHEN THE
THUNDERSTORMS DEVELOP. MODELS ARE SIMILAR THAT IT IS DRAPED ACROSS
THE CENTRAL TO SOUTHERN PART OF THE FORECAST AREA. HAVE KEPT CHANCES
ACROSS THE AREA WITH THUNDERSTORMS ALONG THE FRONT. THUNDERSTORM
CHANCES CONTINUE INTO SATURDAY NIGHT AS ANOTHER UPPER LEVEL WAVE
MOVES INTO THE AREA SATURDAY NIGHT AND THUNDERSTORMS ON THE HIGH
PLAINS START TO MOVE INTO THE AREA LATE SATURDAY NIGHT. THE NEXT
WAVE AFFECTS THE AREA SUNDAY AND SUNDAY NIGHT. THE BEST CHANCE FOR
THUNDERSTORMS WITH THIS ROUND WILL BE SUNDAY NIGHT IN THE SOUTHERN
PART OF THE FORECAST AREA.
THERE IS A BREAK ON MONDAY AS A SURFACE HIGH PRESSURE SYSTEM PUSHES
INTO THE AREA. THE BREAK IS SHORT LIVED FOR PORTIONS OF THE AREA.
ANOTHER UPPER LEVEL WAVE STARTS TO AFFECT THE CENTRAL HIGH PLAINS
MONDAY NIGHT THROUGH TUESDAY NIGHT...BUT WITH AN UPPER LEVEL RIDGE
ACROSS THE AREA AND THE SURFACE HIGH MOVING TO THE EAST THE STORMS
SHOULD BE MAINLY IN THE WESTERN PART OF THE FORECAST AREA.
WEDNESDAY THROUGH THURSDAY A SERIES OF UPPER LEVEL WAVES MOVE
THROUGH THE AREA AND BRING CHANCES FOR THUNDERSTORMS TO THE FORECAST
AREA AGAIN. MODELS HAVE A FEW DIFFERENCES IN THE TIMING OF THE
PRECIPITATION.
TEMPERATURES THROUGH THE PERIOD WILL BE MOSTLY IN THE 80S WITH A
LITTLE VARIATION UP AND DOWN THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 556 AM CDT FRI JUN 14 2013
SHOWERS AND THUNDERSTORMS WILL TRACK THROUGH KGRI EARLY THIS
MORNING WITH DRY WEATHER EXPECTED BY LATE MORNING THROUGH EARLY
AFTERNOON. THE FRONT WILL SINK TO AROUND KGRI BY MID AFTERNOON AND
THEN STALL OUT RESULTING IN FAIRLY LIGHT AND SHIFTY WINDS. WILL
STILL HAVE TO WATCH OUT FOR GUSTY THUNDERSTORM WINDS DURING THE
LATE AFTERNOON AND EVENING HOURS WITH ANY THUNDERSTORMS THAT
REDEVELOP.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
951 AM CDT FRI JUN 14 2013
.DISCUSSION...
MADE A FEW UDPATES FOR ONGOING MORNING TRENDS. CONVECTION IS
SLIDING EASTWARD OUT OF WESTERN IOWA...AND AREA OF LIGHT SHOWERS
ALONG THE I-80 CORRIDOR BETWEEN SEWARD AND LINCOLN IS DISSIPATING.
HOWEVER...A NEW LINE OF SHOWERS AND ISOLATED THUNDER HAS CROPPED
UP FROM ALBION TO YANKTON. HAVE ADJUSTED POPS FOR THESE
TRENDS...AND DO EXPECT ACTIVITY TO FADE/MOVE OUT THROUGH THE
REMAINDER OF THE MORNING HOURS...WITH THUNDERSTORMS DEVELOPING
AGAIN LATER THIS AFTERNOON...AND A WINDOW OF DRY WEATHER BETWEEN.
MAYES
&&
.PREV DISCUSSION... /ISSUED 714 AM CDT FRI JUN 14 2013/
AVIATION...
12Z TAFS FOR KOMA...KLNK...KOFK.
VFR CEILINGS ARE FORECAST ACROSS MUCH OF THE AREA DURING THE
DAY...EXCEPT IN THE VICINITY OF THUNDERSTORMS WHERE CEILINGS CAN
BE EXPECTED TO BE MVFR. SOUTHERLY WINDS ARE FORECAST TO BECOME
GUSTY BY 18Z WITH GUSTS AS HIGH AS 25 KT. SHRA OVER THE FORECAST
AREA SHOULD DIMINISH BY MID MORNING AND THEN TSRA IS EXPECTED TO
DEVELOP...ESPECIALLY AFTER 21Z.
SMITH
PREV DISCUSSION... /ISSUED 340 AM CDT FRI JUN 14 2013/
DISCUSSION...
.MAIN FORECAST CONCERN IS CONVECTION THIS MORNING...THEN AGAIN
THIS AFTERNOON AND TONIGHT...
LATEST WATER VAPOR IMAGERY AND RAP 500MB ANALYSIS SHOW A TROUGH AXIS
EXTENDING FROM LOW PRESSURE IN ALBERTA SOUTHWARD TOWARD NORTHERN
NEVADA. DOWNSTREAM...A HIGH PRESSURE RIDGE AXIS EXTENDS FROM THE
SOUTHERN PLAINS INTO CENTRAL MANITOBA. AN EMBEDDED WEAK SHORTWAVE
CONTINUES TO MOVE UP THE BACKSIDE OF THE RIDGE AND INTO CENTRAL
NEBRASKA. WIDELY SCATTERED THUNDERSTORMS CONTINUE IN ADVANCE OF
THIS SHORTWAVE AND THESE ARE SLOWLY MOVING EAST-NORTHEAST. MOST
LIKELY SCENARIO TO PLAY OUT SEEMS TO BE WHAT THE HRRR AND RAP
HAVE BEEN INDICATING AND THAT IS FOR THE CONVECTION ASSOCIATED
WITH THE ABOVE MENTIONED SHORTWAVE TO CONTINUE TO CLUSTER TOGETHER AND
DRIFT EAST ACROSS THE CWA THROUGH THE MORNING WHERE STRONG
ISENTROPIC UPGLIDE RESIDES. SOME OF THESE MAY CONTAIN MARGINALLY
SEVERE HAIL...AIDED BY A VEERED 35-45KT LOW LEVEL JET.
CLOUD COVER FROM MORNING CONVECTIVE ACTIVITY WILL LIKELY INHIBIT
STRONG HEATING INITIALLY. AS HIGH PLAINS SFC LOW PRESSURE SLIDES
EAST TODAY...A WARM FRONT WILL EXTEND WEST TO EAST ACROSS THE
FORECAST AREA BRINGING A RAPID WARM UP TO THE AREA THIS
AFTERNOON...ESPECIALLY IN OUR SOUTH. IN ADDITION...SFC DEWPOINTS
ARE PROGGED TO RISE INTO THE LOWER 70S BY AFTERNOON WHICH MAY BE A
BIT HIGH AND PUSHES FORECASTED SFC BASED CAPE VALUES INTO THE 4000
J/KG RANGE. WITH AN INCREASING SOUTHWEST LOW LEVEL JET EARLY IN
THE EVENING AIDING TSTMS...THINK BUSIEST TIMEFRAME IN TERMS OF ANY
SEVERE STORMS WILL BE FROM ABOUT 23Z-03Z NEAR THE SFC BOUNDARY.
THIS WILL MOST LIKELY LINGER INTO THE OVERNIGHT HOURS AS A
POSSIBLE MCS AS THE BOUNDARY REMAINS IN THE AREA. ALL THIS LIMITED
OF COURSE BY CAPPING INVERSION...ESPECIALLY THIS AFTERNOON.
WILL CONTINUE TO CARRY POPS THROUGH THE WEEKEND AS THE BOUNDARY
REMAINS OVER THE AREA ALTHOUGH DO NOT THINK WE WILL HAVE A
CONTINUOUS PERIOD OF THUNDERSTORMS THROUGHOUT THE ENTIRE WEEKEND.
WITH WESTERLY MID LEVEL FLOW...HIGHER POPS ARE WARRANTED WITH
THIS BOUNDARY EXTENDING OVER THE AREA.
NO CHANGES INTO THE LATER PERIODS WITH DRIER WEATHER ON TAP FOR
MONDAY AND TUESDAY AND A BIT MORE ACTIVE MID TO LATE WEEK.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
714 AM CDT FRI JUN 14 2013
.AVIATION...
12Z TAFS FOR KOMA...KLNK...KOFK.
VFR CEILINGS ARE FORECAST ACROSS MUCH OF THE AREA DURING THE
DAY...EXCEPT IN THE VICINITY OF THUNDERSTORMS WHERE CEILINGS CAN
BE EXPECTED TO BE MVFR. SOUTHERLY WINDS ARE FORECAST TO BECOME
GUSTY BY 18Z WITH GUSTS AS HIGH AS 25 KT. SHRA OVER THE FORECAST
AREA SHOULD DIMINISH BY MID MORNING AND THEN TSRA IS EXPECTED TO
DEVELOP...ESPECIALLY AFTER 21Z.
SMITH
&&
.PREV DISCUSSION... /ISSUED 340 AM CDT FRI JUN 14 2013/
DISCUSSION...
..MAIN FORECAST CONCERN IS CONVECTION THIS MORNING...THEN AGAIN
THIS AFTERNOON AND TONIGHT...
LATEST WATER VAPOR IMAGERY AND RAP 500MB ANALYSIS SHOW A TROUGH AXIS
EXTENDING FROM LOW PRESSURE IN ALBERTA SOUTHWARD TOWARD NORTHERN
NEVADA. DOWNSTREAM...A HIGH PRESSURE RIDGE AXIS EXTENDS FROM THE
SOUTHERN PLAINS INTO CENTRAL MANITOBA. AN EMBEDDED WEAK SHORTWAVE
CONTINUES TO MOVE UP THE BACKSIDE OF THE RIDGE AND INTO CENTRAL
NEBRASKA. WIDELY SCATTERED THUNDERSTORMS CONTINUE IN ADVANCE OF
THIS SHORTWAVE AND THESE ARE SLOWLY MOVING EAST-NORTHEAST. MOST
LIKELY SCENARIO TO PLAY OUT SEEMS TO BE WHAT THE HRRR AND RAP
HAVE BEEN INDICATING AND THAT IS FOR THE CONVECTION ASSOCIATED
WITH THE ABOVE MENTIONED SHORTWAVE TO CONTINUE TO CLUSTER TOGETHER AND
DRIFT EAST ACROSS THE CWA THROUGH THE MORNING WHERE STRONG
ISENTROPIC UPGLIDE RESIDES. SOME OF THESE MAY CONTAIN MARGINALLY
SEVERE HAIL...AIDED BY A VEERED 35-45KT LOW LEVEL JET.
CLOUD COVER FROM MORNING CONVECTIVE ACTIVITY WILL LIKELY INHIBIT
STRONG HEATING INITIALLY. AS HIGH PLAINS SFC LOW PRESSURE SLIDES
EAST TODAY...A WARM FRONT WILL EXTEND WEST TO EAST ACROSS THE
FORECAST AREA BRINGING A RAPID WARM UP TO THE AREA THIS
AFTERNOON...ESPECIALLY IN OUR SOUTH. IN ADDITION...SFC DEWPOINTS
ARE PROGGED TO RISE INTO THE LOWER 70S BY AFTERNOON WHICH MAY BE A
BIT HIGH AND PUSHES FORECASTED SFC BASED CAPE VALUES INTO THE 4000
J/KG RANGE. WITH AN INCREASING SOUTHWEST LOW LEVEL JET EARLY IN
THE EVENING AIDING TSTMS...THINK BUSIEST TIMEFRAME IN TERMS OF ANY
SEVERE STORMS WILL BE FROM ABOUT 23Z-03Z NEAR THE SFC BOUNDARY.
THIS WILL MOST LIKELY LINGER INTO THE OVERNIGHT HOURS AS A
POSSIBLE MCS AS THE BOUNDARY REMAINS IN THE AREA. ALL THIS LIMITED
OF COURSE BY CAPPING INVERSION...ESPECIALLY THIS AFTERNOON.
WILL CONTINUE TO CARRY POPS THROUGH THE WEEKEND AS THE BOUNDARY
REMAINS OVER THE AREA ALTHOUGH DO NOT THINK WE WILL HAVE A
CONTINUOUS PERIOD OF THUNDERSTORMS THROUGHOUT THE ENTIRE WEEKEND.
WITH WESTERLY MID LEVEL FLOW...HIGHER POPS ARE WARRANTED WITH
THIS BOUNDARY EXTENDING OVER THE AREA.
NO CHANGES INTO THE LATER PERIODS WITH DRIER WEATHER ON TAP FOR
MONDAY AND TUESDAY AND A BIT MORE ACTIVE MID TO LATE WEEK.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS HASTINGS NE
605 AM CDT FRI JUN 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 413 AM CDT FRI JUN 14 2013
THE PRIMARY FORECAST CONCERN CENTERS AROUND THE CHANCE OF
THUNDERSTORMS EARLY THIS MORNING AND THEN AGAIN LATER THIS
AFTERNOON. SOME THUNDERSTORMS LATE THIS AFTERNOON AND EVENING WILL
LIKELY BE SEVERE.
THE FIRST ROUND OF THUNDERSTORMS HAVE BEEN WEAKENING AS THEY TRACK
EAST. THE HRRR SEEMS TO HAVE A GOOD HANDLE ON THESE STORMS AND
TRACKS THEM ALL THE WAY ACROSS OUR FORECAST AREA GENERALLY ALONG
THE INTERSTATE 80/HWY 6 CORRIDOR. CURRENT EXPECTATION IS THAT ALL
OF THESE THUNDERSTORMS WILL HAVE EITHER DECAYED OR BE EAST OF OUR
FORECAST AREA BY MID MORNING WITH DRY CONDITIONS FROM LATE
MORNING THROUGH MID AFTERNOON. THE HIGH CIRRUS LEFT OVER FROM THE
MORNING THUNDERSTORMS WILL THIN AND WE SHOULD SEE A GOOD DEAL OF
SUNSHINE TODAY HELPING TEMPERATURES SKY ROCKET. AN INCREASING
SOUTH WIND IN THE WARM SECTOR TODAY...WHICH WILL INCLUDE ALL OF
OUR FORECAST AREA EXCEPT MAYBE OUR FAR NORTHERN ZONES WILL ALSO
HELP TO GIVE TEMPERATURES A BOOST. EXPECT AFTERNOON HIGHS TO RANGE
FROM AROUND 90 IN OUR FAR NORTH AROUND ORD TO OVER 100 ACROSS MUCH
OF NORTH CENTRAL KANSAS.
THERE IS GOOD FORECAST MODEL AGREEMENT THAT AFTERNOON
THUNDERSTORMS WILL EVENTUALLY OVERCOME AN ELEVATED CAP
AND INITIATE ALONG A SFC FRONT THAT WILL STRETCH FROM NORTHEAST
NEBRASKA INTO SOUTH CENTRAL NEBRASKA AND NORTHWEST KANSAS. MLCAPE
VALUES ALONG THE FRONT WILL RANGE FROM 2000 TO 4000 J/KG MAKING
FOR A VERY UNSTABLE ATMOSPHERE. 0-6KM WIND SHEAR WILL BE MORE
MARGINAL AT 25 TO 35 KTS. THE COMBINATION OF STRONG
INSTABILITY...AT LEAST MARGINAL SHEAR...AND A FRONTAL BOUNDARY
SHOULD BE MORE THAN SUFFICIENT TO ALLOW FOR SEVERAL SEVERE
THUNDERSTORMS ACROSS OUR FORECAST AREA LATE THIS AFTERNOON AND
EVENING. EXPECT INITIATION WILL LIKELY BE AFTER 4 PM WITH THE
GREATEST SEVERE WEATHER THREAT IN THE 5 PM TO 10 PM TIME FRAME.
REDEVELOPMENT AND POSSIBLE TRAINING OF THUNDERSTORMS ALONG THE
FRONT WILL BE POSSIBLE LEADING TO LOCALIZED HEAVY RAIN. THE
HIGHEST CHANCE OF THUNDERSTORMS WILL GENERALLY BE NEAR HIGHWAY 30
FROM MERRICK COUNTY DOWN INTO GRAND ISLAND AND KEARNEY...AND THEN
SOUTHWEST INTO GOSPER AND FURNAS COUNTY. THE CHANCE OF
THUNDERSTORMS WILL DECREASE PRETTY FAST AS YOU HEAD SOUTHEAST OF
THIS CORRIDOR INTO NORTH CENTRAL KANSAS. THE PRIMARY SEVERE
WEATHER THREATS WILL BE LARGE HAIL TO THE SIZE OF GOLFBALLS AND
WIND GUSTS TO 70 MPH. WIND IS A BIG CONCERN DUE TO THE INVERTED V
FORECAST SOUNDING AND STEEP LAPSE RATES ALONG WITH THE OBVIOUSLY
HIGH CAPE. THE TORNADO THREAT WILL BE LIMITED DUE TO GENERALLY
WEAK LOW LEVEL SHEAR AND HIGHER LCL HEIGHTS. THE LIMITED TORNADO
THREAT WILL BE ACROSS OUR NORTHEASTERN CWA PRIMARY FOR THE KEARNEY
AND GRAND ISLAND AREAS AND POINTS NORTHEAST WHERE LCL HEIGHTS WILL
BE THE LOWEST AND THERE MIGHT BE SOME BACKING OF THE SFC WIND BY
EARLY EVENING...BUT AGAIN THIS IS ONLY A LIMITED THREAT WITH THE
PRIMARY THREATS TODAY BEING BIG HAIL AND STRONG THUNDERSTORM
WINDS.
THE CONVECTION WILL SLOWLY PUSH EAST TONIGHT AND AREAS ALONG AND
NORTH OF HIGHWAY 6 MAY ALSO SEE SOME ADDITIONAL THUNDERSTORM
REDEVELOPMENT DURING THE LATE EVENING HOURS AS THE LOW LEVEL JET
STRENGTHENS AND NOSES INTO OUR NEBRASKA ZONES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 413 AM CDT FRI JUN 14 2013
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
AN ACTIVE WEATHER PATTERN WILL BE FOUND ACROSS THE AREA THROUGH THIS
PERIOD. MODELS ARE SIMILAR IN THE MAIN FEATURES WITH SUBTLE
DIFFERENCES IN THE FINER DETAILS. SEVERAL UPPER LEVEL LOWS MOVE
THROUGH THE AREA DURING THE PERIOD AND EACH HAS THE POTENTIAL FOR
SOME THUNDERSTORMS. WITH THIS IN MIND THERE ARE CHANCES FOR
THUNDERSTORMS NEARLY EVERY PERIOD FOR PORTIONS OF THE AREA.
THE FIRST UPPER LEVEL LOW MOVES THROUGH THE AREA SATURDAY.
THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG A NEARLY STATIONARY
FRONT. THE QUESTION IS WHERE THIS FRONT WILL BE AND WHEN THE
THUNDERSTORMS DEVELOP. MODELS ARE SIMILAR THAT IT IS DRAPED ACROSS
THE CENTRAL TO SOUTHERN PART OF THE FORECAST AREA. HAVE KEPT CHANCES
ACROSS THE AREA WITH THUNDERSTORMS ALONG THE FRONT. THUNDERSTORM
CHANCES CONTINUE INTO SATURDAY NIGHT AS ANOTHER UPPER LEVEL WAVE
MOVES INTO THE AREA SATURDAY NIGHT AND THUNDERSTORMS ON THE HIGH
PLAINS START TO MOVE INTO THE AREA LATE SATURDAY NIGHT. THE NEXT
WAVE AFFECTS THE AREA SUNDAY AND SUNDAY NIGHT. THE BEST CHANCE FOR
THUNDERSTORMS WITH THIS ROUND WILL BE SUNDAY NIGHT IN THE SOUTHERN
PART OF THE FORECAST AREA.
THERE IS A BREAK ON MONDAY AS A SURFACE HIGH PRESSURE SYSTEM PUSHES
INTO THE AREA. THE BREAK IS SHORT LIVED FOR PORTIONS OF THE AREA.
ANOTHER UPPER LEVEL WAVE STARTS TO AFFECT THE CENTRAL HIGH PLAINS
MONDAY NIGHT THROUGH TUESDAY NIGHT...BUT WITH AN UPPER LEVEL RIDGE
ACROSS THE AREA AND THE SURFACE HIGH MOVING TO THE EAST THE STORMS
SHOULD BE MAINLY IN THE WESTERN PART OF THE FORECAST AREA.
WEDNESDAY THROUGH THURSDAY A SERIES OF UPPER LEVEL WAVES MOVE
THROUGH THE AREA AND BRING CHANCES FOR THUNDERSTORMS TO THE FORECAST
AREA AGAIN. MODELS HAVE A FEW DIFFERENCES IN THE TIMING OF THE
PRECIPITATION.
TEMPERATURES THROUGH THE PERIOD WILL BE MOSTLY IN THE 80S WITH A
LITTLE VARIATION UP AND DOWN THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 556 AM CDT FRI JUN 14 2013
SHOWERS AND THUNDERSTORMS WILL TRACK THROUGH KGRI EARLY THIS
MORNING WITH DRY WEATHER EXPECTED BY LATE MORNING THROUGH EARLY
AFTERNOON. THE FRONT WILL SINK TO AROUND KGRI BY MID AFTERNOON AND
THEN STALL OUT RESULTING IN FAIRLY LIGHT AND SHIFTY WINDS. WILL
STILL HAVE TO WATCH OUT FOR GUSTY THUNDERSTORM WINDS DURING THE
LATE AFTERNOON AND EVENING HOURS WITH ANY THUNDERSTORMS THAT
REDEVELOP.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
509 AM CDT FRI JUN 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 413 AM CDT FRI JUN 14 2013
THE PRIMARY FORECAST CONCERN CENTERS AROUND THE CHANCE OF
THUNDERSTORMS EARLY THIS MORNING AND THEN AGAIN LATER THIS
AFTERNOON. SOME THUNDERSTORMS LATE THIS AFTERNOON AND EVENING WILL
LIKELY BE SEVERE.
THE FIRST ROUND OF THUNDERSTORMS HAVE BEEN WEAKENING AS THEY TRACK
EAST. THE HRRR SEEMS TO HAVE A GOOD HANDLE ON THESE STORMS AND
TRACKS THEM ALL THE WAY ACROSS OUR FORECAST AREA GENERALLY ALONG
THE INTERSTATE 80/HWY 6 CORRIDOR. CURRENT EXPECTATION IS THAT ALL
OF THESE THUNDERSTORMS WILL HAVE EITHER DECAYED OR BE EAST OF OUR
FORECAST AREA BY MID MORNING WITH DRY CONDITIONS FROM LATE
MORNING THROUGH MID AFTERNOON. THE HIGH CIRRUS LEFT OVER FROM THE
MORNING THUNDERSTORMS WILL THIN AND WE SHOULD SEE A GOOD DEAL OF
SUNSHINE TODAY HELPING TEMPERATURES SKY ROCKET. AN INCREASING
SOUTH WIND IN THE WARM SECTOR TODAY...WHICH WILL INCLUDE ALL OF
OUR FORECAST AREA EXCEPT MAYBE OUR FAR NORTHERN ZONES WILL ALSO
HELP TO GIVE TEMPERATURES A BOOST. EXPECT AFTERNOON HIGHS TO RANGE
FROM AROUND 90 IN OUR FAR NORTH AROUND ORD TO OVER 100 ACROSS MUCH
OF NORTH CENTRAL KANSAS.
THERE IS GOOD FORECAST MODEL AGREEMENT THAT AFTERNOON
THUNDERSTORMS WILL EVENTUALLY OVERCOME AN ELEVATED CAP
AND INITIATE ALONG A SFC FRONT THAT WILL STRETCH FROM NORTHEAST
NEBRASKA INTO SOUTH CENTRAL NEBRASKA AND NORTHWEST KANSAS. MLCAPE
VALUES ALONG THE FRONT WILL RANGE FROM 2000 TO 4000 J/KG MAKING
FOR A VERY UNSTABLE ATMOSPHERE. 0-6KM WIND SHEAR WILL BE MORE
MARGINAL AT 25 TO 35 KTS. THE COMBINATION OF STRONG
INSTABILITY...AT LEAST MARGINAL SHEAR...AND A FRONTAL BOUNDARY
SHOULD BE MORE THAN SUFFICIENT TO ALLOW FOR SEVERAL SEVERE
THUNDERSTORMS ACROSS OUR FORECAST AREA LATE THIS AFTERNOON AND
EVENING. EXPECT INITIATION WILL LIKELY BE AFTER 4 PM WITH THE
GREATEST SEVERE WEATHER THREAT IN THE 5 PM TO 10 PM TIME FRAME.
REDEVELOPMENT AND POSSIBLE TRAINING OF THUNDERSTORMS ALONG THE
FRONT WILL BE POSSIBLE LEADING TO LOCALIZED HEAVY RAIN. THE
HIGHEST CHANCE OF THUNDERSTORMS WILL GENERALLY BE NEAR HIGHWAY 30
FROM MERRICK COUNTY DOWN INTO GRAND ISLAND AND KEARNEY...AND THEN
SOUTHWEST INTO GOSPER AND FURNAS COUNTY. THE CHANCE OF
THUNDERSTORMS WILL DECREASE PRETTY FAST AS YOU HEAD SOUTHEAST OF
THIS CORRIDOR INTO NORTH CENTRAL KANSAS. THE PRIMARY SEVERE
WEATHER THREATS WILL BE LARGE HAIL TO THE SIZE OF GOLFBALLS AND
WIND GUSTS TO 70 MPH. WIND IS A BIG CONCERN DUE TO THE INVERTED V
FORECAST SOUNDING AND STEEP LAPSE RATES ALONG WITH THE OBVIOUSLY
HIGH CAPE. THE TORNADO THREAT WILL BE LIMITED DUE TO GENERALLY
WEAK LOW LEVEL SHEAR AND HIGHER LCL HEIGHTS. THE LIMITED TORNADO
THREAT WILL BE ACROSS OUR NORTHEASTERN CWA PRIMARY FOR THE KEARNEY
AND GRAND ISLAND AREAS AND POINTS NORTHEAST WHERE LCL HEIGHTS WILL
BE THE LOWEST AND THERE MIGHT BE SOME BACKING OF THE SFC WIND BY
EARLY EVENING...BUT AGAIN THIS IS ONLY A LIMITED THREAT WITH THE
PRIMARY THREATS TODAY BEING BIG HAIL AND STRONG THUNDERSTORM
WINDS.
THE CONVECTION WILL SLOWLY PUSH EAST TONIGHT AND AREAS ALONG AND
NORTH OF HIGHWAY 6 MAY ALSO SEE SOME ADDITIONAL THUNDERSTORM
REDEVELOPMENT DURING THE LATE EVENING HOURS AS THE LOW LEVEL JET
STRENGTHENS AND NOSES INTO OUR NEBRASKA ZONES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 413 AM CDT FRI JUN 14 2013
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
AN ACTIVE WEATHER PATTERN WILL BE FOUND ACROSS THE AREA THROUGH THIS
PERIOD. MODELS ARE SIMILAR IN THE MAIN FEATURES WITH SUBTLE
DIFFERENCES IN THE FINER DETAILS. SEVERAL UPPER LEVEL LOWS MOVE
THROUGH THE AREA DURING THE PERIOD AND EACH HAS THE POTENTIAL FOR
SOME THUNDERSTORMS. WITH THIS IN MIND THERE ARE CHANCES FOR
THUNDERSTORMS NEARLY EVERY PERIOD FOR PORTIONS OF THE AREA.
THE FIRST UPPER LEVEL LOW MOVES THROUGH THE AREA SATURDAY.
THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG A NEARLY STATIONARY
FRONT. THE QUESTION IS WHERE THIS FRONT WILL BE AND WHEN THE
THUNDERSTORMS DEVELOP. MODELS ARE SIMILAR THAT IT IS DRAPED ACROSS
THE CENTRAL TO SOUTHERN PART OF THE FORECAST AREA. HAVE KEPT CHANCES
ACROSS THE AREA WITH THUNDERSTORMS ALONG THE FRONT. THUNDERSTORM
CHANCES CONTINUE INTO SATURDAY NIGHT AS ANOTHER UPPER LEVEL WAVE
MOVES INTO THE AREA SATURDAY NIGHT AND THUNDERSTORMS ON THE HIGH
PLAINS START TO MOVE INTO THE AREA LATE SATURDAY NIGHT. THE NEXT
WAVE AFFECTS THE AREA SUNDAY AND SUNDAY NIGHT. THE BEST CHANCE FOR
THUNDERSTORMS WITH THIS ROUND WILL BE SUNDAY NIGHT IN THE SOUTHERN
PART OF THE FORECAST AREA.
THERE IS A BREAK ON MONDAY AS A SURFACE HIGH PRESSURE SYSTEM PUSHES
INTO THE AREA. THE BREAK IS SHORT LIVED FOR PORTIONS OF THE AREA.
ANOTHER UPPER LEVEL WAVE STARTS TO AFFECT THE CENTRAL HIGH PLAINS
MONDAY NIGHT THROUGH TUESDAY NIGHT...BUT WITH AN UPPER LEVEL RIDGE
ACROSS THE AREA AND THE SURFACE HIGH MOVING TO THE EAST THE STORMS
SHOULD BE MAINLY IN THE WESTERN PART OF THE FORECAST AREA.
WEDNESDAY THROUGH THURSDAY A SERIES OF UPPER LEVEL WAVES MOVE
THROUGH THE AREA AND BRING CHANCES FOR THUNDERSTORMS TO THE FORECAST
AREA AGAIN. MODELS HAVE A FEW DIFFERENCES IN THE TIMING OF THE
PRECIPITATION.
TEMPERATURES THROUGH THE PERIOD WILL BE MOSTLY IN THE 80S WITH A
LITTLE VARIATION UP AND DOWN THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1239 AM CDT FRI JUN 14 2013
THUNDERSTORMS TO THE WEST OF GRAND ISLAND CONTINUE TO DIE AS THEY
SLOWLY MOVE EAST. CAN NOT RULE OUT A FEW LIGHT RAIN SHOWERS EARLY
THIS MORNING...BUT CHANCES ARE LOW ENOUGH TO KEEP IT OUT OF THE
TAF FOR NOW. THE BETTER CHANCE FOR THUNDERSTORMS WILL BE LATE
AFTERNOON AND LASTING THROUGH THE EVENING AS A SFC FRONT STALLS
OUT RIGHT OVER KGRI. THE WIND WILL PICK UP AFTER SUNRISE THIS
MORNING AND THEN DIE DOWN THIS EVENING AS THE FRONT STALLS
OVERHEAD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
954 AM CDT FRI JUN 14 2013
.UPDATE...
ISSUED AT 950 AM CDT FRI JUN 14 2013
MAIN CLUSTER OF CONVECTION VCNTY MOT LIFTING NNE AS SHORTWAVE
LIFTS INTO S CENTRAL CANADA AND AT MOST MAY CLIP FAR NE FA.
ELSEWHERE IN OUR FA CONVECTION OVERALL WEAKENING WITH LTG STRIKES NO
LONGER NOTED. BASED ON CURRENT RADAR TRENDS...CLOUDS MOVING INTO
FA AND BOUNDARY WELL TO OUR WEST BACKED OFF ON POPS REMAINDER OF
AM INTO MID AFTERNOON. CLOUDS MOVING IN AND MAY RESTRICT
TEMPERATURE RECOVERY SOME BUT ANY BREAKS WILL LIFT TEMPERATURES SO
WILL LEAVE TEMPS AS IS FOR NOW.
UPDATE ISSUED AT 702 AM CDT FRI JUN 14 2013
MORE SHOWERS AND A FEW STORMS HAVE GONE UP ACROSS THE NORTHWESTERN
AND NORTH CENTRAL CWA ALONG AN AREA OF WARM AIR ADVECTION. RAP HAS
SEEMED TO HAVE A GOOD HANDLE ON THIS ACTIVITY OVERNIGHT AND HAS
SOME PRECIP CONTINUING OVER THE CENTRAL CWA FOR THE NEXT FEW
HOURS. THE NEXT ROUND IS SEEN ACROSS CENTRAL ND ON RADAR AND
SHOULD START ENTERING THE WESTERN CWA BY LATE MORNING. ADJUSTED
POPS ACCORDINGLY FOR TODAYS ACTIVITY.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 347 AM CDT FRI JUN 14 2013
MAIN CONCERN FOR THE SHORT TERM IS HOW MUCH CONVECTION WE GET
TODAY AND IF ANY WILL BE SEVERE.
THE MAIN UPPER TROUGH IS STILL OUT OVER WA/OR/ID BUT WV LOOP SHOWS
SOME LEAD SHORTWAVES SETTING OFF ACTIVITY OVER THE NORTHERN
ROCKIES. THE UPPER RIDGE AXIS CURRENTLY OVER THE RED RIVER VALLEY
WILL MOVE EAST INTO MN TODAY. THERE HAS BEEN SHOWERS AND STORMS
DEVELOPING OVER THE SOUTHEASTERN COUNTIES AS WELL AS JUST OUTSIDE
OUR NORTHWEST ALONG THE FRONT EDGE OF THE 850MB WARM AIR ADVECTION
AND RIGHT EXIT REGION OF THE LOW LEVEL JET. NONE OF THE MODELS
EXCEPT FOR THE RAP HAS HAD A GOOD HANDLE ON THE ACTIVITY. THINK
THAT THIS BAND OF LIGHT CONVECTION WILL SLOWLY SPREAD EASTWARD
DURING THE MORNING HOURS. WILL MAKE LAST MINUTE ADJUSTMENTS TO
POPS/WX BASED ON RADAR TRENDS.
BY LATE THIS AFTERNOON AND EVENING...THE MAIN SHORTWAVE WILL
APPROACH AND WILL HELP PUSH THE SFC TROUGH AXIS INTO THE RED RIVER
VALLEY. THINK THAT THERE WILL BE PLENTY OF LIFT TO WORK WITH...THE
QUESTION IS HOW MUCH INSTABILITY WILL BE AVAILABLE FOR CONVECTION.
THE MODELS HAVE DECENT 1000-2000 J/KG ALONG THE SFC TROUGH AXIS
THIS AFTERNOON...BUT THERE IS ALSO QUITE A BIT OF A CAP WITH 700MB
TEMPS IN THE LOW TEENS C. THERE IS ALSO THE QUESTION OF HOW MUCH
CLOUD COVER WILL BE HANGING AROUND FROM THIS MORNINGS ACTIVITY.
THERE CONTINUES TO BE QUITE A BIT OF PRECIP BREAKING OUT ALONG THE
SFC TROUGH ACCORDING TO THE MODELS. WILL CONTINUE TO KEEP FAIRLY
HIGH POPS AND WILL MENTION THE POSSIBILITY OF SOME HAIL AND WINDS
IN THE HWO...BUT WILL KEEP A MENTION OUT OF THE GRIDS FOR NOW.
THE UPPER TROUGH WILL MOVE INTO CENTRAL CANADA AND THE NORTHERN
PLAINS TONIGHT...WITH THE SFC TROUGH AXIS/WEAK FRONTAL BOUNDARY
PUSHING THE REST OF THE WAY THROUGH THE CWA. DECENT WINDS WILL
HELP KEEP LOWS IN THE 50S. NEAR ZONAL FLOW SETS UP OVER ND FOR
SATURDAY WITH THE MAIN SFC LOW WELL TO OUR NORTH OVER MANT/SASK.
WEST WINDS WILL REMAIN OVER THE PLAINS...AND WITH THE BEST COLD
AIR ADVECTION HOLDING OFF FOR NOW...HIGHS ON SATURDAY SHOULD AGAIN
CLIMB INTO THE MID TO UPPER 70S.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 347 AM CDT FRI JUN 14 2013
FOR THE REST OF THE WEEKEND...ANOTHER UPPER TROUGH WILL BEGIN TO
DIG DOWN OUT OF CANADA BY SUNDAY...PUSHING A MUCH MORE SIGNIFICANT
COLD FRONT DOWN INTO THE CWA. THERE COULD BE SOME SHOWERS AND
THUNDERSTORMS ALONG AND BEHIND THE FRONT...SO CONTINUED WITH
CHANCE POPS MAINLY ALONG THE INTERNATIONAL BORDER SUNDAY. PRECIP
WILL MOVE OFF TO THE SOUTH AND EAST SUNDAY NIGHT AS THE COLD FRONT
PUSHES THE REST OF THE WAY THROUGH THE CWA. HIGHS ON SUNDAY WILL
DEPEND ON EXACT TIMING OF THE FRONT...BUT FOR NOW HAVE HIGHS
AROUND 70 IN THE NORTHWEST AND NEAR 80 IN THE SOUTHEAST.
MODELS IN FAIR AGREEMENT WITH THE BEGINNING OF THE NEXT WORK WEEK. A
COOL MONDAY WILL SEE A CHC FOR SOME SHOWER ACTIVITY WITH COLD CORE
ALOFT ALLOWING LOW CONVECTIVE TEMPS TO BE REACHED IF ANY SFC SOLAR
OCCURS. SFC HIGH WITH 500MB RIDGING WILL GIVE OVERALL DRY AND WARM
WEATHER TUESDAY AND WEDNESDAY BEFORE THE NEXT SYSTEM MOVES INTO THE
REGION THURSDAY BRINGING THE NEXT CHC OF RAIN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 702 AM CDT FRI JUN 14 2013
VFR CONDITIONS WILL CONTINUE THROUGH MOST OF THE PERIOD ALTHOUGH
THERE COULD BE SOME DROPS TO MVFR UNDER SHOWERS AND THUNDERSTORMS
FOR A BRIEF PERIOD. FOR NOW IT SEEMS THAT THIS MORNINGS ACTIVITY
WILL BE NORTH OF THE TAF SITES...BUT LATER ON THIS AFTERNOON
SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE AREA. SOUTHEASTERLY
WINDS WILL PICK UP INTO THE 15 TO 20 KT RANGE WITH SOME HIGHER
GUSTS. AFTER A TROUGH AXIS/WEAK COLD FRONT MOVES THROUGH DURING
THE AFTERNOON TO EVENING...WINDS WILL SHIFT TO THE WEST AND
DECREASE. SKIES SHOULD BEGIN TO CLEAR TOWARDS THE END OF THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...JR
LONG TERM...JR/JK
AVIATION...JR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
702 AM CDT FRI JUN 14 2013
.UPDATE...
ISSUED AT 702 AM CDT FRI JUN 14 2013
MORE SHOWERS AND A FEW STORMS HAVE GONE UP ACROSS THE NORTHWESTERN
AND NORTH CENTRAL CWA ALONG AN AREA OF WARM AIR ADVECTION. RAP HAS
SEEMED TO HAVE A GOOD HANDLE ON THIS ACTIVITY OVERNIGHT AND HAS
SOME PRECIP CONTINUING OVER THE CENTRAL CWA FOR THE NEXT FEW
HOURS. THE NEXT ROUND IS SEEN ACROSS CENTRAL ND ON RADAR AND
SHOULD START ENTERING THE WESTERN CWA BY LATE MORNING. ADJUSTED
POPS ACCORDINGLY FOR TODAYS ACTIVITY.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 347 AM CDT FRI JUN 14 2013
MAIN CONCERN FOR THE SHORT TERM IS HOW MUCH CONVECTION WE GET
TODAY AND IF ANY WILL BE SEVERE.
THE MAIN UPPER TROUGH IS STILL OUT OVER WA/OR/ID BUT WV LOOP SHOWS
SOME LEAD SHORTWAVES SETTING OFF ACTIVITY OVER THE NORTHERN
ROCKIES. THE UPPER RIDGE AXIS CURRENTLY OVER THE RED RIVER VALLEY
WILL MOVE EAST INTO MN TODAY. THERE HAS BEEN SHOWERS AND STORMS
DEVELOPING OVER THE SOUTHEASTERN COUNTIES AS WELL AS JUST OUTSIDE
OUR NORTHWEST ALONG THE FRONT EDGE OF THE 850MB WARM AIR ADVECTION
AND RIGHT EXIT REGION OF THE LOW LEVEL JET. NONE OF THE MODELS
EXCEPT FOR THE RAP HAS HAD A GOOD HANDLE ON THE ACTIVITY. THINK
THAT THIS BAND OF LIGHT CONVECTION WILL SLOWLY SPREAD EASTWARD
DURING THE MORNING HOURS. WILL MAKE LAST MINUTE ADJUSTMENTS TO
POPS/WX BASED ON RADAR TRENDS.
BY LATE THIS AFTERNOON AND EVENING...THE MAIN SHORTWAVE WILL
APPROACH AND WILL HELP PUSH THE SFC TROUGH AXIS INTO THE RED RIVER
VALLEY. THINK THAT THERE WILL BE PLENTY OF LIFT TO WORK WITH...THE
QUESTION IS HOW MUCH INSTABILITY WILL BE AVAILABLE FOR CONVECTION.
THE MODELS HAVE DECENT 1000-2000 J/KG ALONG THE SFC TROUGH AXIS
THIS AFTERNOON...BUT THERE IS ALSO QUITE A BIT OF A CAP WITH 700MB
TEMPS IN THE LOW TEENS C. THERE IS ALSO THE QUESTION OF HOW MUCH
CLOUD COVER WILL BE HANGING AROUND FROM THIS MORNINGS ACTIVITY.
THERE CONTINUES TO BE QUITE A BIT OF PRECIP BREAKING OUT ALONG THE
SFC TROUGH ACCORDING TO THE MODELS. WILL CONTINUE TO KEEP FAIRLY
HIGH POPS AND WILL MENTION THE POSSIBILITY OF SOME HAIL AND WINDS
IN THE HWO...BUT WILL KEEP A MENTION OUT OF THE GRIDS FOR NOW.
THE UPPER TROUGH WILL MOVE INTO CENTRAL CANADA AND THE NORTHERN
PLAINS TONIGHT...WITH THE SFC TROUGH AXIS/WEAK FRONTAL BOUNDARY
PUSHING THE REST OF THE WAY THROUGH THE CWA. DECENT WINDS WILL
HELP KEEP LOWS IN THE 50S. NEAR ZONAL FLOW SETS UP OVER ND FOR
SATURDAY WITH THE MAIN SFC LOW WELL TO OUR NORTH OVER MANT/SASK.
WEST WINDS WILL REMAIN OVER THE PLAINS...AND WITH THE BEST COLD
AIR ADVECTION HOLDING OFF FOR NOW...HIGHS ON SATURDAY SHOULD AGAIN
CLIMB INTO THE MID TO UPPER 70S.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 347 AM CDT FRI JUN 14 2013
FOR THE REST OF THE WEEKEND...ANOTHER UPPER TROUGH WILL BEGIN TO
DIG DOWN OUT OF CANADA BY SUNDAY...PUSHING A MUCH MORE SIGNIFICANT
COLD FRONT DOWN INTO THE CWA. THERE COULD BE SOME SHOWERS AND
THUNDERSTORMS ALONG AND BEHIND THE FRONT...SO CONTINUED WITH
CHANCE POPS MAINLY ALONG THE INTERNATIONAL BORDER SUNDAY. PRECIP
WILL MOVE OFF TO THE SOUTH AND EAST SUNDAY NIGHT AS THE COLD FRONT
PUSHES THE REST OF THE WAY THROUGH THE CWA. HIGHS ON SUNDAY WILL
DEPEND ON EXACT TIMING OF THE FRONT...BUT FOR NOW HAVE HIGHS
AROUND 70 IN THE NORTHWEST AND NEAR 80 IN THE SOUTHEAST.
MODELS IN FAIR AGREEMENT WITH THE BEGINNING OF THE NEXT WORK WEEK. A
COOL MONDAY WILL SEE A CHC FOR SOME SHOWER ACTIVITY WITH COLD CORE
ALOFT ALLOWING LOW CONVECTIVE TEMPS TO BE REACHED IF ANY SFC SOLAR
OCCURS. SFC HIGH WITH 500MB RIDGING WILL GIVE OVERALL DRY AND WARM
WEATHER TUESDAY AND WEDNESDAY BEFORE THE NEXT SYSTEM MOVES INTO THE
REGION THURSDAY BRINGING THE NEXT CHC OF RAIN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 702 AM CDT FRI JUN 14 2013
VFR CONDITIONS WILL CONTINUE THROUGH MOST OF THE PERIOD ALTHOUGH
THERE COULD BE SOME DROPS TO MVFR UNDER SHOWERS AND THUNDERSTORMS
FOR A BRIEF PERIOD. FOR NOW IT SEEMS THAT THIS MORNINGS ACTIVITY
WILL BE NORTH OF THE TAF SITES...BUT LATER ON THIS AFTERNOON
SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE AREA. SOUTHEASTERLY
WINDS WILL PICK UP INTO THE 15 TO 20 KT RANGE WITH SOME HIGHER
GUSTS. AFTER A TROUGH AXIS/WEAK COLD FRONT MOVES THROUGH DURING
THE AFTERNOON TO EVENING...WINDS WILL SHIFT TO THE WEST AND
DECREASE. SKIES SHOULD BEGIN TO CLEAR TOWARDS THE END OF THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...JR
LONG TERM...JR/JK
AVIATION...JR
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
709 AM CDT FRI JUN 14 2013
.AVIATION...
FOR THE 12Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE VALID
FORECAST PERIOD. LOW CHANCES OF SHOWERS AND THUNDERSTORMS LATE
THIS AFTERNOON AND ON SATURDAY ARE THE PRIMARY FORECAST CONCERNS.
A WEAK BUT LARGE UPPER LOW REMAINS IN PLACE NEAR DEL RIO...AND IS
EXPECTED TO MOVE NORTH THROUGHOUT THE DAY TODAY. AREA AIRPORTS ARE
EXPECTED TO REMAIN UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE
WHICH IS EXPECTED TO SLIDE SOUTHEAST OVER NORTH TX TODAY AND
SHOULD KEEP US DRY THROUGH SATURDAY MORNING.
WE WILL HAVE TO CAREFULLY MONITOR AREA TAF SITES FOR SHOWERS AND
THUNDERSTORMS DEVELOPING FURTHER EAST THAN MODEL GUIDANCE
EXPLICITLY FORECASTS THOUGH. MORNING RUNS OF THE RAP AND NAM BOTH
INDICATE THAT WE HAVE VERY LITTLE TO NO CAP REMAINING FOR STORMS
OVER THE DFW AREA AND WACO BY 23Z. THIS DOES NOT MEAN WE WILL GET
STORMS...HOWEVER ANY WEAK FORCING FOR ASCENT MAY BE ENOUGH TO SET
OFF SOME /SURPRISE/ SHOWER OR THUNDERSTORM ACTIVITY NEAR OR ON TOP
OF AREA AIRPORTS LATE THIS AFTERNOON INTO THE EVENING HOURS.
CHANCES OF THIS ARE TOO LOW TO DO ANYTHING BUT MENTION THE
POSSIBILITY IN THE DISCUSSION AT THIS TIME.
WE WILL HAVE A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS TOMORROW
AFTERNOON AT ALL AREA AIRPORTS AS THE UPPER LOW IS EXPECTED TO
MOVE NORTHEAST OVER NORTH TX. THE BEST CHANCE OF STORMS LOOKS TO
OCCUR AFTER 18Z AT THIS TIME...WHICH IS BEYOND THE CURRENT VALID
FORECAST PERIOD.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 422 AM CDT FRI JUN 14 2013/
CHANGES IN THE WEATHER PATTERN SHOULD BRING SOME MUCH NEED RAIN TO
NORTH TEXAS THIS WEEKEND THROUGH EARLY NEXT WEEK. THE UPPER LEVEL
RIDGE THAT HAS DOMINATED NORTH TEXAS WEATHER THIS PAST WEEK WILL
MOVE EAST TO THE MISSISSIPPI VALLEY REGION WHILE A WEAK CLOSED LOW...
CURRENTLY CENTERED NEAR THE BIG BEND...OPENS UP AND MOVES EAST.
PRECIPITATION ASSOCIATED WITH THE UPPER LOW SHOULD REMAIN
WEST/SOUTHWEST OF NORTH TEXAS TODAY AS LARGE SCALE SUBSIDENCE
CONTINUES OVER THE REGION. HOWEVER...SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE ACROSS THE WESTERN SECTIONS OF
NORTH TEXAS AS EARLY AS SATURDAY MORNING AND ACROSS THE REMAINDER
OF REGION SATURDAY AFTERNOON AND EVENING. MARGINAL INSTABILITY AND
SHEAR WILL KEEP MOST IF NOT ALL STORMS BELOW SEVERE LIMITS...BUT
PRECIPITABLE WATER VALUES AROUND 2 INCHES WILL RESULT EFFICIENT
RAIN PRODUCING STORMS. THERE WILL BE MODERATE STEERING FLOW SO
FLASH FLOODING IS NOT EXPECTED. THE UPPER TROUGH AXIS WILL MOVE
EAST OF THE REGION OVERNIGHT SATURDAY AND PRECIPITATION CHANCES
WILL END.
BRIEF RIDGING ALOFT IS EXPECTED SUNDAY. HOWEVER...THE RIDGE IS
PROGGED TO FLATTEN SUNDAY NIGHT AS AN UPPER TROUGH DEEPENS AND
MOVES EAST ACROSS THE NORTHERN AND CENTRAL PLAINS. A COLD FRONT
WILL MOVE SOUTHWARD ACROSS THE CENTRAL PLAINS BEHIND THE EASTWARD
MOVING UPPER TROUGH. THE FRONT SHOULD CROSS THE RED RIVER ON
MONDAY AND STALL OVER NORTH TEXAS UNTIL WEDNESDAY. THE ECMWF SOLUTION
AND GFS ARE STARTING TO COME IN LINE WITH EACH OTHER REGARDING THE
STRENGTH OF THE COLD FRONT AND POSITION OF THE ASSOCIATED PRECIP.
HAVE DECIDED TO RAISE POPS IN THE MONDAY THROUGH WEDNESDAY TIME
FRAME...MAINLY BASED ON THE RUN TO RUN CONSISTENCY OF THE ECMWF.
THE BEST RAIN CHANCES SHOULD BE ALONG AND JUST NORTH OF THE COLD
FRONT...ESPECIALLY TUESDAY WHEN A SHORT WAVE ROTATES THROUGH THE
REGION AND PROVIDES ADDITIONAL FORCING. WILL KEEP THE HIGHEST POPS
ACROSS THE NORTHERN HALF OF THE REGION BASED ON THE EXPECTED
POSITION OF THE FRONT. PRECIPITATION CHANCES SHOULD DECREASE FROM
WEST TO EAST TUESDAY NIGHT THROUGH WEDNESDAY AS THE SHORT WAVE
TROUGH MOVES EAST AND THE COLD FRONT BEGINS TO LIFT NORTHWARD IN
RESPONSE TO A DEVELOPING LEE TROUGH.
UPPER LEVEL HIGH PRESSURE WILL BUILD BACK OVER NORTH TEXAS THE END
OF NEXT WEEK THROUGH THE WEEKEND AND RESULT IN WARMER AND RAIN
FREE CONDITIONS.
AFTER ANOTHER HOT DAY TODAY WITH HIGHS IN THE MIDDLE AND UPPER 90S...
TEMPERATURES SHOULD BE A BIT COOLER SATURDAY DUE TO INCREASED
CLOUD COVER AND PRECIPITATION. HOTTER TEMPS WILL BRIEFLY RETURN SUNDAY
DUE TO MORE SUN AND BUILDING HIGH PRESSURE. HOWEVER...SLIGHTLY COOLER
TEMPERATURES ARE ON TAP MONDAY THROUGH WEDNESDAY DUE TO THE
PASSAGE OF THE COLD FRONT AND EXPECTED PRECIP. AFTERNOON HIGHS
MONDAY THROUGH WEDNESDAY WILL RANGE FROM THE UPPER 80S IN THE
NORTH TO THE MID 90S IN THE SOUTH. HIGH TEMPERATURES THE REMAINDER
OF NEXT WEEK WILL BE GENERALLY IN THE MIDDLE 90S.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 97 77 94 77 97 / 0 5 30 10 10
WACO, TX 96 75 95 75 95 / 0 5 20 10 10
PARIS, TX 97 74 92 73 93 / 0 5 20 20 10
DENTON, TX 98 74 94 75 96 / 0 5 30 10 10
MCKINNEY, TX 97 75 93 73 94 / 0 5 30 20 10
DALLAS, TX 98 78 95 77 95 / 0 5 20 10 10
TERRELL, TX 97 76 94 74 94 / 0 5 20 10 10
CORSICANA, TX 97 75 93 75 93 / 0 5 20 10 10
TEMPLE, TX 94 73 93 74 93 / 0 5 20 10 10
MINERAL WELLS, TX 96 74 94 72 95 / 0 10 30 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
903 AM EDT FRI JUN 14 2013
.SYNOPSIS...
COOL HIGH PRESSURE WILL GRADUALLY BUILD INTO THE AREA TONIGHT INTO
FRIDAY BRINGING IN MUCH DRIER AIR INTO THE WEEKEND. MOISTURE WILL
START TO RETURN ON SUNDAY AS THE HIGH MOVES OFFSHORE FOLLOWED BY
A COLD FRONT EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 900 AM EDT FRIDAY...
MADE SOME MINOR ADJUSTMENTS TO CLOUD COVER AND TEMPERATURES
TODAY. NAM AND RAP STILL SHOWED SOME LIGHT SHOWERS WITH THE WEAK
SHORTWAVE THAT DROPS SOUTH ACROSS THE MID ATLANTIC REGION.
MOISTURE REMAINS QUITE SHALLOW BUT LAPSE RATES SUPPORT LIGHT
POP MENTION ACROSS THE NORTH.
AS OF 410 AM EDT FRIDAY...
UPPER TROF MOVES EAST OF THE FORECAST AREA THIS MORNING. A WEAK
SHORT WAVE TRACKS DOWN THE WEST SIDE OF THE TROF AND ACROSS THE
MID ATLANTIC REGION TODAY. TEMPERATURES ALOFT ARE COOL ENOUGH FOR
LARGE LAPSE RATES BUT MOISTURE IS LIMITED. BUFKIT FORECAST
SOUNDINGS SHOWED MOISTURE CONFINED TO SHALLOW LAYER BETWEEN 900
AND 800 MB. MODELS SHOWED BEST POTENTIAL FOR SHOWERS IN THE
WESTERN UPSLOPE AREAS OF SOUTHEAST WEST VIRGINIA AND EAST OF HOT
SPRINGS AND LYNCHBURG THIS AFTERNOON. ANY PRECIPITATION WILL BE
LIGHT.
THE STRATOCUMULUS AND ANY SHOWERS THAT DEVELOP THIS AFTERNOON WILL
DISSIPATE THIS EVENING WITH THE LOSS OF HEATING. 850 MB START OUT
AROUND 35 KNOTS THIS MORNING AND DIMINISH TO LESS THAN 20 KNOTS BY
THIS EVENING. HIGH PRESSURE BUILDS IN TONIGHT AND WILL BE CENTERED
OVER WEST VIRGINIA BY SATURDAY MORNING. SURFACE WINDS WILL
DECOUPLE...AND WITH A CLEAR SKY EXPECT VERY FAVORABLE CONDITIONS
FOR COOLING. SHELTERED VALLEYS IN THE WEST MAY DROP JUST BELOW 50
DEGREES OVERNIGHT.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 326 AM EDT FRIDAY...
SUNDAY WILL PRESENT THE FIRST OPPORTUNITY FOR SHOWERS...MAINLY WEST
OF THE BLUE RIDGE. AN UPPER DISTURBANCE HEADING OUR WAY IS RATHER
SHEARED AND WEAK...ALSO INSTABILITY ISN`T THAT GREAT. THINKING THE
MODELS MAY BE OVERDOING THE AMOUNT OF PRECIP AND COVERAGE SO WENT
A LITTLE LESS THAN GUIDANCE POPS AND DELAYED MOST OF THE RAIN
UNTIL LATE AFTERNOON. COMPARED TO LAST NIGHT`S RUNS...THERE IS A
DEEPER TROUGH OVER THE EASTERN US MONDAY WITH A STRONGER UPPER LOW
OVER SE CANADA...ALSO THE UPPER RIDGE OVER THE SOUTHEASTERN STATES
IS FLATTER. THIS CONFIGURATION WILL SEND A COLD FRONT IN OUR
DIRECTION MONDAY NIGHT AND TUESDAY...WITH MORE SHOWERS AND SOME
STORMS OUT AHEAD OF THE BOUNDARY FOR A CLOUDY YET WARM AND HUMID
MONDAY.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 1215 PM EDT THURSDAY...
HIGH PRESSURE WILL BE OFF THE SOUTHEAST COAST WHILE INCREASING
HUMIDITY AND PIECES OF SHORTWAVE ENERGY MOVE ACROSS THE AREA AHEAD
OF A FRONT. THE PATTERN SUGGESTS THAT MON-TUE WILL HAVE THE BETTER
THREAT OF SHOWERS/STORMS WITH THE FRONT SHIFTING SOUTHEAST OF US BY
WEDNESDAY. HIGH PRESSURE BUILDS IN BEHIND THIS FRONT OVER THE GREAT
LAKES SOUTH INTO THE TN VALLEY WEDNESDAY AND THURSDAY. THE FRONT
WILL STAY HUNG UP ACROSS THE SOUTHEAST SO THERE IS AN OUTSIDE SHOT
THAT SOME OF OUR SRN CWA COUNTIES COULD SEE A FEW SHOWERS WED OR
THU...ALTHOUGH FOR NOW LEFT IT MAINLY DRY. TEMPS ABOVE NORMAL EARLY
BECOME MORE NORMAL POST FRONTAL PASSAGE...WITH HUMIDITY DROPPING
SOME BY WED NIGHT-THU.
&&
.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
AS OF 725 AM EDT FRIDAY...
SCATTERED TO BROKEN STRATOCUMULUS AT ROA/BCB/LWB/BLF AND THE
WESTERN UPSLOPE AREAS WILL GRADUALLY DISSIPATE THIS MORNING.
NORTHWEST SURFACE WINDS GUSTING UP TO 20 KNOTS WILL TURN TO THE
NORTH AND WIND SPEEDS WILL DIMINISH BY AFTERNOON.
HIGH PRESSURE WILL BUILD IN TODAY AND SATURDAY RESULTING IN VFR
WEATHER. GRIDDED LAMP GUIDANCE SUGGESTED LIFR FOG IN THE
GREENBRIER VALLEY AT THE KLWB AIRPORT LATE TONIGHT. THE SKY WILL
BE CLEAR WITH A CALM WIND BUT AIR MASS WILL BE DRY. CONFIDENCE NOT
HIGH ENOUGH AT THIS TIME TO INCLUDE IN THE TAF.
LOW LEVEL SOUTHERLY FLOW RETURNS ON SUNDAY AHEAD OF ANOTHER FRONT
MOVING INTO THE MIDWEST/GREAT LAKES. MAY SEE FOG AT THE TYPICAL
LOCATIONS SUNDAY MORNING... KLWB/KBCB...OTHERWISE VFR. THE
RETURN OF MOISTURE WILL BRING ISOLATED STORMS TO THE MOUNTAINS
SUNDAY AFTERNOON...WITH BETTER COVERAGE ACROSS THE REGION MONDAY
AND TUESDAY AHEAD/ALONG AND APPROACHING COLD FRONT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...KM/WP
LONG TERM...WP
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS SPOKANE WA
428 AM PDT Fri Jun 14 2013
.SYNOPSIS...
Scattered mountain showers are expected today as temperatures still
remain on the cool side. Drier and much warmer weather can be
expected for the weekend. The next weather system will arrive by
Monday and bring more showery and cool weather for much of the
upcoming work week.
&&
.DISCUSSION...
Today and tonight...The Inland NW will be under the influence of an
exiting upper level trough of low pressure and cold air for the
next 24 hours. Currently this trough resides across eastern
Washington. Most of the daytime convection has diminished, but
radar does show some light shower activity associated with a few
upper level impulses and terrain. Of the upper level disturbances,
there are two main ones that we will be monitoring. The first is
within the base of the upper level trough and is pivoting across
the northeast Oregon and the Clearwater mountains into southwest
Montana with a band of light showers and embedded thunderstorms.
This area continues to pull away from our region and may brush our
southeast borders with mid level clouds and a few early morning
sprinkles. The other impulse is seen on satellite dropping south
from BC down the Okanogan valley. The Kelowna radar does show
light showers, and if they hold together, they could reach Omak
and Republic early this morning. Updated the early morning grids
to reflect this trend. The HRRR does pick up on these light
showers and spreads them from the Okanogan Valley and Highlands,
toward Colville and Sandpoint area early Friday morning as the
upper level trough axis shifts east. Daytime heating and surface
based instability will be enhanced within the upper level trough
axis which will be over northeast Washington and north Idaho
during the afternoon and early evening. Cape values will reach
near 400 j/kg, not as steep as yesterday but enough for the
potential of a couple embedded thunderstorms especially over the
mountains. Meanwhile, a more stable, dry westerly flow will
develop across the western zones. The instability will quickly
decrease after mid evening as an upper level ridge of high
pressure builds into the region with drying and clearing Friday
night. Although temperatures will moderate gradually today and
tonight, they will still be cooler than normal. /rfox.
Saturday and Saturday night: As the Low exits the region a ridge will
build into Eastern Washington...bringing drier and warmer weather
to much of the forecast area. Weak diffluence and daytime heating
will begin to affect the Cascades by Saturday afternoon, leading
to potential showers or isolated thunderstorm along the crest of
the Cascades. The next Low pressure will move into position just
of the coast of northern BC. /JDC
Sunday through Monday...Model agreement is good and consistent
over previous runs in depicting an increasingly moist and deep
southerly flow regime over the forecast area as a new upper level
low slowly approaches the forecast area off the Pacific. This
pattern strongly argues fro increasing temperatures each day...as
will as the return of a perceptible convective threat...probably
beginning Sunday mainly over the Cascades and on Monday broadening
out to include a chance of showers and thunderstorms over the
mountains ringing the basin...but also a smaller threat of a stray
shower or afternoon thunderstorm over the basin. Moisture and
instability will be increasing...but so far models do not sense
any especially stimulating short wave or disturbance necessary to
trigger widespread convection. An unsettled early summer-like
regime would best characterize this period of the forecast.
Monday night through Thursday...This period will cover the passage
directly aloft of the incoming closed low. For the last few days
the EC and GFS have been consistent and in reasonable agreement
in tracking this upper low directly across the forecast area. Two
distinct events are becoming increasingly likely during this
evolution...the first will be another day of increased convective
activity as the increasingly moist southerly flow continues to
impact the region on Tuesday...showers and thunderstorms will be
hit-and-miss but highly likely to be prowling most of the
forecast area justifying solid chance pops...with high
temperatures cooler than previous days but only down to around
seasonal normal values.
By Wednesday and Thursday there is an increased likelihood that a
much wetter and cooler pattern will develop as the low center
passes directly over the region...and on at least one of these
days...at this time Wednesday looks like the best bet but
Thursday also a possibility...or maybe both days...a downright wet dense
shower/stratiform rain event associated with a deformation band
will develop probably over the east and north reaches of the
forecast area. Model details are still a little nebulous that far
out but in good agreement with the overall pattern which
historically implies a wetter solution than climatology would
suggest. /Fugazzi
&&
.AVIATION...
12Z TAFS: One disturbance is pulling away from the KWS/KPUW this
morning and will see skies tempo clear this morning. Meanwhile a
secondary disturbance will bring mid and high level clouds to the
KGEG-KCOE area after 15z with isolated showers. AFter 19z, surface
based instability will enhance the cumulus clouds and the best
chance for showers and thunderstorms look to be north and east of
KGEG-KCOE. Drier westerly flow will be found from KEAT to KMWH.
Expect the convection to diminish by 02z with clearing and VFR
conditions overnight. /rfox.
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 68 47 77 53 84 56 / 20 10 0 0 10 10
Coeur d`Alene 67 42 77 50 85 53 / 20 20 0 0 10 10
Pullman 68 38 77 47 84 49 / 20 10 0 0 0 10
Lewiston 75 48 85 54 91 56 / 20 0 0 0 0 10
Colville 74 45 81 49 88 54 / 40 20 0 0 20 20
Sandpoint 68 39 77 45 85 48 / 30 30 0 0 10 10
Kellogg 67 43 73 50 82 54 / 40 10 0 0 10 10
Moses Lake 77 46 86 57 90 59 / 10 0 0 0 10 20
Wenatchee 75 52 85 63 89 61 / 0 0 0 10 10 20
Omak 75 45 83 54 87 57 / 20 0 0 10 20 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
640 AM CDT FRI JUN 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CDT FRI JUN 14 2013
MAIN FORECAST FOCUS IS ON POTENTIAL FOR HEAVY RAIN/FLASH FLOODING
LATER TODAY THROUGH SATURDAY.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A HIGHLY AMPLIFIED PATTERN ACROSS NORTH AMERICA...CONSISTING
OF TROUGHING OVER ALBERTA AND IDAHO...RIDGING FROM THE SOUTHERN
PLAINS INTO MANITOBA...AND TROUGHING FROM SOUTHEAST CANADA SOUTHWARD
ALONG THE EAST COAST OF THE U.S.. THE FORECAST AREA LIES ON THE
SUBSIDENT SIDE OF THE RIDGING...RESULTING IN HIGH PRESSURE AT THE
SURFACE WHICH EXISTS OVER WISCONSIN. 00Z SOUNDINGS FROM MPX...GRB
AND DVN DEPICTED A DRY AIRMASS WITH THIS HIGH PRESSURE AREA WITH
PRECIPITABLE WATER VALUES OF 0.7-0.8 INCHES OR 80-90 PERCENT OF
NORMAL. THE DRY AIRMASS HAS HELPED KEEP SKIES MOSTLY CLEAR OVERNIGHT
AND WITH LIGHT WINDS...TEMPERATURES HAVE DROPPED INTO THE UPPER 40S
TO UPPER 50S. MEANWHILE...TO THE WEST UNDER AND WEST OF THE UPPER
RIDGE AXIS...MOISTURE HAS BEEN GRADUALLY ADVECTING NORTHWARD THROUGH
THE PLAINS ON A 30-45 KT 850MB JET PER VWP DATA. GOES DERIVED
PRECIPITABLE WATER SHOWED VALUES OF 1-1.5 INCHES ACROSS MUCH OF THE
PLAINS...HIGHEST ACROSS SOUTH CENTRAL NEBRASKA AND NORTH CENTRAL KS.
THIS MAXIMA WAS ALSO CORRELATED WITH THE REMNANTS OF AN MCS THAT
INITIATED OFF THE FRONT RANGE IN COLORADO YESTERDAY AFTERNOON. ALONG
WITH THE INCREASED MOISTURE...00Z RAOBS SHOWED 850MB TEMPS OF 16-21C
FROM RAPID CITY TO OMAHA AND TOPEKA...QUITE A BIT WARMER COMPARED TO
THE 10-13C AROUND THE FORECAST AREA. ALONG THE GRADIENT OF THIS
TEMPERATURE DIFFERENCE...A NARROW LINE OF SHOWERS AND THUNDERSTORMS
HAS BROKE OUT OVER SOUTHWEST MN INTO WESTERN IA.
OVER THE NEXT 24 HOURS...THE UPPER RIDGE AXIS OVER THE PLAINS IS
PROGGED TO SHIFT EAST OVER THE FORECAST AREA. THIS IS IN RESPONSE TO
THE TROUGH OVER IDAHO AND ALBERTA EJECTING NORTHEAST...AS WELL AS
FORMING A DEEP CLOSED LOW CIRCULATION OVER CENTRAL SASKATCHEWAN.
WHAT THIS MEANS FOR THE FORECAST AREA IS ALL OF THAT WARMER 850MB
AIR AND HIGHER PRECIPITABLE WATER UNDER THE UPPER RIDGE WILL MOVE
TOWARDS US. GIVEN THE WARM ADVECTION PATTERN...EXPECT CONCERN FOR
PRECIPITATION TO INCREASE. IN ADDITION...CONVECTIVELY INDUCED
SHORTWAVES FROM CONVECTION COMING OFF THE ROCKIES AND THE PLAINS
THIS MORNING...AND THOSE THAT FIRE THIS AFTERNOON...WILL ALSO PLAY A
ROLE AS THEY HEAD NORTHEAST AROUND THE UPPER RIDGE.
FOR TODAY...GENERAL CONSENSUS FROM THE MODELS IS FOR INCREASING
310-315K ISENTROPIC LIFT AND 700MB MOISTURE TRANSPORT TO COME ACROSS
THE FORECAST AREA DURING THE AFTERNOON. ANTICIPATING AN
ALTOSTRATUS/ACCAS DECK TO FORM AS A RESULT AND OVERSPREAD MUCH OF
THE AREA. THIS CAN ALREADY BE SEEN ALONG THE DAKOTAS/MN BORDER WHERE
THOSE SHOWERS AND THUNDERSTORMS HAVE BEEN OCCURRING. HAVE
CONTINUED THE MENTION OF SOME LOW PROBABILITIES FOR PRECIPITATION
WEST OF THE MS RIVER EARLY THIS AFTERNOON TO ACCOUNT FOR THIS SHOWER
POTENTIAL.
LATE IN THE AFTERNOON...SOMETHING TO WATCH IS THE 14.00Z NAM
SCENARIO WHICH DEPICTS A LARGER AMOUNT OF CONVECTION OVER SOUTH
CENTRAL MN AND NORTH CENTRAL IA...CLIPPING FAR WESTERN PORTIONS OF
THE FORECAST AREA. THE GFS/ECMWF/REGIONAL CANADIAN ARE VERY
SIMILAR...THOUGH QPF VALUES ARE NOT NEARLY AS HIGH WHICH MAY BE A
RESULT OF MODEL RESOLUTION. THE SITUATION APPEARS TO BE A RESULT OF
INCREASING 700-850MB MOISTURE TRANSPORT...ON THE LEADING EDGE OF THE
HIGHER PRECIPITABLE WATER VALUES OF 1.5-1.8 INCHES PER RAP COMING
INTO WESTERN IA...CAPE OF 1000 J/KG OR SO THAT IS UNCAPPED LIFTED
FROM 725MB...AND A POSSIBLE RIGHT ENTRANCE REGION OF A JET STREAK
TRACKING SOUTHEAST THROUGH WISCONSIN. SHOULD THIS PAN OUT...GIVEN
THE HIGH PRECIPITABLE WATER...THESE STORMS WILL BE HEAVY RAIN
PRODUCERS.
NAM/GFS/ECMWF/REGIONAL CANADIAN MOISTURE TRANSPORT FIELDS FROM
925-700MB ARE ALL IN AGREEMENT THAT THE STREAM SHIFTS NORTHEAST
TONIGHT...FOLLOWING THE UPPER RIDGE AXIS. THUS...THINKING THE
CONVECTION THAT FIRES LATE THIS AFTERNOON SHOULD SLOWLY PROGRESS
EASTWARD THROUGH THE FORECAST AREA. ADDITIONALLY...IT APPEARS THERE
IS A SECOND SURGE OF MOISTURE TRANSPORT COMING UP OUT OF KS INTO
CENTRAL IA OVERNIGHT...LIKELY FIRING MORE CONVECTION ON ITS NOSE
FROM NORTH CENTRAL INTO EASTERN IA. THE ECMWF HAS BEEN EXTREMELY
CONSISTENT RUN TO RUN WITH THIS.
ALTHOUGH INSTABILITY IS ADVECTING TOWARDS US ON THIS MOISTURE
TRANSPORT...THE INSTABILITY IS TALL AND SKINNY. WITH WARM CLOUD
DEPTHS APPROACHING 14 KFT...THINKING HEAVY RAIN WOULD BE THE MAIN
SEVERE WEATHER CONCERN. ADDITIONALLY...THE 2-7KM SHEAR WHICH IS MORE
REPRESENTATIVE OF THE INSTABILITY USED BY THE STORMS...IS LESS THAN
30 KTS. SEE THE HYDROLOGY SECTION BELOW FOR MORE ON THE IMPACTS FROM
THE PRECIPITATION. MAIN THING TO NOTE HERE IS THAT GIVEN THE MOIST
SOILS OVER PORTIONS OF NORTHEAST IA AND SOUTHEAST MN...ANY HEAVY
RAIN MAY CAUSE FLASH FLOODING...ESPECIALLY IN FLOYD AND MITCHELL
COUNTIES IN IA. THEREFORE...HAVE ISSUED FLASH FLOOD WATCHES FOR THE
MOST CONCERNING AREAS.
850MB TEMPERATURES ARE PROGGED TO STAY BETWEEN 10-13C TODAY. WITH
INCREASING CLOUDS...TEMPERATURES SHOULD END UP NEAR OR A LITTLE
BELOW YESTERDAY HIGHS. WARMER NIGHT ON TAP AS HIGHER DEWPOINTS MOVE
IN ACCOMPANYING THE HIGHER PRECIPITABLE WATER.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 329 AM CDT FRI JUN 14 2013
SATURDAY THROUGH MONDAY...
MODELS ARE IN GOOD AGREEMENT FLATTENING THE UPPER RIDGE OVER THE
AREA ON SATURDAY...AGAIN RESULTING FROM THE EJECTING IDAHO TROUGH.
EVENTUALLY...THE CLOSED UPPER LOW THAT FORMED OVER SASKATCHEWAN ON
SATURDAY WILL APPROACH THE AREA...PROGGED TO DROP INTO CENTRAL MN AT
12Z MONDAY AS A SHORTWAVE TROUGH. THIS TROUGH MAY EVEN BEGIN TO
PHASE WITH THE GENERAL TROUGHING OVER SOUTHEAST CANADA AS INDICATED
BY THE 00Z ECMWF.
WITH THE FLOW TURNING ZONAL ON SATURDAY...THE MAIN MOISTURE
TRANSPORT STREAM SUPPORTING CONVECTION TONIGHT SHOULD PUSH OFF TO
THE EAST. THUS...LIKE CLIMATOLOGY FOR NOCTURNAL CONVECTION...
EXPECTING IT TO WEAKEN THROUGH THE MORNING HOURS. HOWEVER...OUTFLOW
BOUNDARIES FROM THE CONVECTION AND WHAT SHOULD BE A COLD FRONT AT
THE SURFACE ARE SUGGESTED TO LAY UP OVER SOUTHERN SECTIONS OVER THE
FORECAST AREA. GROWING INSTABILITY FROM ANY DAYTIME HEATING PLUS A
HUMID AIRMASS CHARACTERIZED BY DEWPOINTS IN THE MID-UPPER
60S...ALONG WITH PRECIPITABLE WATER VALUES OF 1.5-1.8 INCHES...
SHOULD PROMOTE RENEWED CONVECTION. AGAIN...HEAVY RAIN WOULD BE THE
MAIN CONCERN AND THUS THE FLASH FLOOD WATCH GOES THROUGH THE DAY
SATURDAY. OUTFLOWS FROM THIS NEW CONVECTION COMBINED WITH THE COLD
FRONT DROPPING SOUTHEAST SHOULD PUSH MUCH OF THE CONVECTION OUT OF
THE AREA SOMETIME DURING THE EVENING. EXACT TIMING STILL HARD TO PIN
DOWN. LEFT SOME LOW CHANCES IN AFTER MIDNIGHT INTO THE DAY SUNDAY
ACROSS FAR SOUTHERN SECTIONS OF THE AREA WITH THE 14.00Z GFS/ECMWF
SHOWING SOME LIGHT QPF LINGERING. HOWEVER...BELIEVE THESE MIGHT BE
ABLE TO BE REMOVED IN LATER FORECASTS WITH A WEAK RIDGE OF HIGH
PRESSURE IN PLACE. ATTENTION SUNDAY NIGHT AND MONDAY TURNS TO THE
TROUGHING DROPPING INTO MINNESOTA. DPVA AHEAD OF THE TROUGH PLUS A
SURGE OF 850-700MB MOISTURE TRANSPORT MAY BE ENOUGH TO KICK OFF SOME
SHOWER AND THUNDERSTORM ACTIVITY. HOWEVER...THE TROUGH IS COMING
THROUGH AT THE WRONG TIME OF DAY TO GET EXCITED ABOUT IT...AND
MOISTURE IS LACKING WITH PRECIPITABLE WATER VALUES MAYBE AROUND 1
INCH. THEREFORE...HAVE ONLY WENT WITH 20-40 PERCENT CHANCES ACROSS
THE FORECAST AREA. 13.12Z/14.00Z ECMWF EVEN SUGGESTS THE TROUGH AND
ITS ASSOCIATED COLD FRONT COULD COME THROUGH THE AREA MAINLY DRY.
WITH WARMER 850MB TEMPS ON SATURDAY...14-17C...AND MORE SUNSHINE ON
SUNDAY WITH SIMILAR READINGS...EXPECT TEMPERATURES TO RISE EACH DAY.
MOST LOCATIONS SHOULD SEE GOOD MIXING ON SUNDAY...BOOSTING HIGHS
INTO THE LOW TO MID 80S. COOLER READINGS ON TAP FOR MONDAY WITH THE
COLD FRONT COMING THROUGH. GENERALLY FOLLOWED A BLEND OF GUIDANCE
FOR HIGHS AND LOWS.
MONDAY NIGHT THROUGH THURSDAY...
VERY GOOD MODEL AGREEMENT EXISTS AMONGST THE 14.00Z
ECMWF/GFS/CANADIAN AND GFS ENSEMBLES ON THE UPPER LEVEL PATTERN.
MUCH OF THE PERIOD IS DOMINATED BY TROUGHING ALONG THE U.S. WEST
COAST...RIDGING FROM THE NORTHWEST TERRITORIES OF CANADA INTO THE
CENTRAL PLAINS...AND TROUGHING OVER EASTERN CANADA INTO THE GREAT
LAKES. THIS MEANS MOSTLY A NORTHWEST FLOW OF COOL AND DRY AIR FROM
CANADA. THUS...MUCH OF THE FORECAST IS DRY. THERE ARE INDICATIONS OF
A SHORTWAVE DROPPING THROUGH THE WESTERN GREAT LAKES ON
THURSDAY...BRINGING A COLD FRONT INTO THE AREA. HAVE INCLUDED 20
PERCENT CHANCES FOR SHOWERS AND THUNDERSTORMS NORTH OF I-90 FOR THIS
FEATURE. TEMPERATURE WISE...THE COOLEST DAY LOOKS TO BE TUESDAY WITH
HIGH PRESSURE OVERHEAD AND 850MB TEMPS OF 8-10C. AIRMASS
MODIFICATION THANKS TO THE STRONG JUNE SUN SHOULD HELP WARM
TEMPERATURES EACH DAY THEREAFTER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 640 AM CDT THU JUN 13 2013
HIGH PRESSURE WILL CONTINUE TO MOVE EAST OF THE AREA TODAY...WITH
LOW PRESSURE AND A COLD FRONT MOVING INTO MN/IA TONIGHT. VFR
CONDITIONS THIS MORNING WILL GIVE WAY TO GRADUALLY LOWERING
CONDITIONS THIS AFTERNOON AND TONIGHT AS THE LOW/FRONT MOVE INTO THE
REGION. WITH A WIDE VARIETY OF CONVECTION OUTCOMES AMONG THE
FORECAST MODELS...NOT A LOT OF CONFIDENCE ON THE DETAILS OF SHRA/
TSRA EXPECTED TO SPREAD WEST TO EAST ACROSS THE AREA LATER THIS
AFTERNOON THRU TONIGHT.
RATHER THAN BURY THE KRST/KLSE TAFS IN LONG PERIODS OF TSRA OR IFR
CONDITIONS WHEN CONFIDENCE IS LOWER THAN AVERAGE...JUST CARRIED A
TREND CIGS/VSBYS GRADUALLY LOWERING INTO MVFR TONIGHT. CONTINUED A
PERIOD OF TSRA THIS EVENING WHEN THERE IS SOME MODEL CONSISTENCY FOR
STRONGER FORCING/INCREASED MOISTURE AND INSTABILITY TO BE OVER THE
AREA. SHRA/EMBEDDED TSRA LOOKING TO PERSIST OVERNIGHT BUT WITH THE
LOWER CONFIDENCE LEFT TSRA MENTION OUT OF THE OVERNIGHT HOURS FOR
NOW.
&&
.HYDROLOGY...LATE THIS AFTERNOON THROUGH SATURDAY
ISSUED AT 329 AM CDT FRI JUN 14 2013
VERY WET SOILS ACROSS MOWER AND FILLMORE COUNTIES IN MN ALONG WITH
MUCH OF NORTHEAST IOWA OVER THE PAST WEEK...AND REALLY THE PAST
COUPLE MONTHS...RESULT IN A HUGE CONCERN FOR FLOODING. THAT 1-2
INCHES OF RAINFALL THAT IMPACTED FLOYD COUNTY IA LATE WEDNESDAY...
MOSTLY IN A SHORT TIME PERIOD...CAUSED A LOT OF FLOODING ISSUES.
EXPECTING A BAND OF THUNDERSTORMS TO MOVE INTO MOWER THROUGH FLOYD
COUNTIES LATE THIS AFTERNOON...SLOWLY MOVING EAST THROUGH THE
EVENING. ADDITIONAL THUNDERSTORMS ARE FORECAST AFTER MIDNIGHT AND
THROUGH MUCH OF THE DAY SATURDAY SOUTH OF I-90. WITH PRECIPITABLE
WATER VALUES OF 1.5-1.8 INCHES AND WARM CLOUD DEPTHS OF 3500-4200
METERS ACCOMPANYING THESE THUNDERSTORMS...HEAVY RAIN IS LIKELY. WE
COULD BE LOOKING AT A WIDESPREAD 1-2 INCHES OF RAINFALL SOUTH OF
I-90...HIGHEST ACROSS NORTHEAST IOWA. LOCALLY HEAVIER RAINFALL IS
EASILY POSSIBLE.
GIVEN THE VERY WET SOILS AND POTENTIAL FOR HEAVY RAIN...HAVE ISSUED
A FLASH FLOOD WATCH FOR MOWER AND FILLMORE COUNTIES IN MN AND MUCH
OF NORTHEAST IA EXCEPT ALLAMAKEE. DEPENDING ON HOW CONVECTION
EVOLVES...THE WATCH MAY NEED TO BE EXPANDED EASTWARD...MOST LIKELY
INTO FAR SOUTHWEST WI.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...FLASH FLOOD WATCH FROM THIS AFTERNOON THROUGH SATURDAY EVENING
FOR MNZ094-095.
IA...FLASH FLOOD WATCH FROM THIS AFTERNOON THROUGH SATURDAY EVENING
FOR IAZ008>010-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RRS
HYDROLOGY....AJ
AREA FORECAST DISCUSSION
NWS FLAGSTAFF AZ
245 PM MST FRI JUN 14 2013
.SYNOPSIS...THERE IS A SLIGHT CHANCE OF THUNDERSTORMS ON SATURDAY
MOSTLY OVER THE HIGHER TERRAIN OF NORTHERN ARIZONA...BUT LITTLE
RAINFALL IS EXPECTED. BREEZY CONDITIONS WILL PERSIST WITH
TEMPERATURES AROUND NORMAL. BY SUNDAY AND INTO NEXT
WEEK...INCREASING SOUTHWEST WINDS AND MUCH DRIER AIR WILL END
THE CHANCE OF ANY THUNDERSTORMS...WITH SEASONABLY WARM TEMPERATURES.
&&
.DISCUSSION...ONLY A FEW ISOLATED SHOWERS OVER THE EASTERN RIM AND
WHITE MTS SO FAR THIS AFTERNOON...LESS THAN YESTERDAY...AND IN
AGREEMENT WITH THE HRRR MODEL RUNS. EXPECT ANY SHOWERS TO DIMINISH
EARLY THIS EVENING BRINGING MOSTLY CLEAR SKIES FOR THE REST OF THE
NIGHT.
MINOR DIGGING OF THE TROUGH OFF THE WEST COAST WILL ALLOW FOR A
MORE SOUTHERLY FETCH ACROSS ARIZONA ON SATURDAY...BRINGING A
TEMPORARY INCREASE IN MOISTURE...AND RESULTING IN ISOLATED TO
SCATTERED WEAK THUNDERSTORM ACTIVITY. MODEL RUNS INDICATE THE
GREATEST CHANCES FOR THUNDERSTORMS WILL BE ALONG AND NORTH OF THE
MOGOLLON RIM SATURDAY AFTERNOON..WHERE THE MOISTURE AXIS COINCIDES
WITH THE TIME OF MAXIMUM HEATING...AND NORTHEASTERLY STORM MOTION.
LITTLE PRECIPITATION IS EXPECTED FROM THE STORMS AS THE LOWER
ATMOSPHERE WILL REMAIN QUITE DRY.
MUCH DRIER AIR ADVECTS INTO THE AREA LATE SUNDAY THROUGH EARLY NEXT
WEEK AS THE FLOW TURNS MORE WESTERLY. NO PRECIPITATION IS EXPECTED
THROUGH NEXT WEEK AS A STRENGTHENING TROUGH DEVELOPS OVER THE
PACIFIC NORTHWEST...KEEPING A VERY DRY SOUTHWESTERLY FLOW IN PLACE
OVER ARIZONA. BREEZY...TO OCCASIONALLY WINDY CONDITIONS CAN BE
EXPECTED BY MIDWEEK...POSSIBLY APPROACHING CRITICAL FIRE WEATHER
THRESHOLDS.
&&
.AVIATION...
FOR THE 00Z PACKAGE...VFR CONDITIONS EXPECTED FOR THE NEXT 24 HOURS.
SOUTHWEST WINDS 10-20 WITH GUSTS TO 25 KTS WILL PERSIST THROUGH
03Z/SAT. ISOLATED HIGH BASED -SHRA/-TSRA MAY EXIST EAST OF A
KFLG-K0V7 LINE WITH GUSTY WINDS ACCOMPANYING ANY THUNDERSTORM
ACTIVITY...TAPERING OFF BY 03Z/SAT. SIMILAR CONDITIONS XPCTED
SATURDAY WITH -SHRA/-TSRA POSSIBLE AFTER 18Z EAST OF A KPRC-KGCN
LINE WITH GUSTY WINDS AND LITTLE RAIN. AVIATION DISCUSSION NOT
UPDATED FOR AMENDMENTS.
&&
.FIRE WEATHER...A MODEST INCREASE IN MOISTURE WILL CONTINUE TO IMPACT
NORTHERN ARIZONA THROUGH SATURDAY. VERY DRY CONDITIONS AND LOW RH
VALUES WILL PERSIST ACROSS FAR WESTERN ZONES...PRIMARILY WEST OF A
KPRC-KFLG LINE WITH DEWPOINTS AND RH INCREASING WITH EASTWARD
EXTENT. PRIMARILY DRY THUNDERSTORM ACTIVITY WHICH HAS BEEN LIMITED
TO THE WHITE MOUNTAIN REGION THE PAST COUPLE DAYS WILL EXPAND
SATURDAY TO ENCOMPASS THE EASTERN TWO THIRDS OF NORTHERN AZ. THESE
THUNDERSTORMS WILL PRODUCE GUSTY WINDS...BUT LITTLE RAIN. THE WHITE
MOUNTAIN AREA MAY FARE BETTER WITH WETTING RAINFALL ACCOMPANYING THE
HEAVIEST DOWNPOURS. DRY AIR ATTEMPTS TO RETURN SUNDAY WITH TSTORM
ACTIVITY BECOMING LIMITED TO THE WHITE MOUNTAINS AND LOWER RH VALUES
PUSHING IN FROM THE WEST.
MONDAY THROUGH WEDNESDAY...
EXPECT BREEZY SOUTHWEST WINDS EACH AFTERNOON WITH SPEEDS BELOW
CRITICAL VALUES. AFTERNOON RELATIVE HUMIDITIES SHOULD BE FROM 10 TO
15 PERCENT ALONG THE MOGOLLON RIM AND SINGLE DIGITS ELSEWHERE.
WEDNESDAY MAY SEE AN INCREASE IN AFTERNOON BREEZINESS AND ENHANCED
FIRE WEATHER POTENTIAL BUT STILL EXPECTED TO REMAIN BELOW CRITICAL
THRESHOLDS FOR NOW. DESPITE THE FORECAST REMAINING BELOW CRITICAL
RED FLAG CONDITIONS...IT MAY APPROACH IT AND FIRE DANGER WILL
REMAIN VERY HIGH WITH HIGH HAINES VALUES EACH AFTERNOON.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC.........BAK
AVIATION.......OUTLER
FIRE WEATHER...OUTLER
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1224 PM MDT FRI JUN 14 2013
.UPDATE...
ISSUED AT 1220 PM MDT FRI JUN 14 2013
INCREASED POPS ACROSS THE SOUTHERN I-25 CORRIDOR AND PARTS OF THE
EASTERN PLAINS TO CLOSER REFLECT CURRENT RADAR TRENDS AND LATEST
HRRR AND RAP RUNS. -PJC
UPDATE ISSUED AT 916 AM MDT FRI JUN 14 2013
UPDATED THE GRIDS TO INCREASE CLOUD COVER ACROSS THE AREA OVER THE
NEXT FEW HOURS. -PJC
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM MDT FRI JUN 14 2013
SOUTHWEST FLOW ALOFT CONTINUES OVER THE AREA TODAY AND TONIGHT...AS
STRONG UPPER TROUGH LIFTS NORTHEAST FROM THE NORTHERN ROCKIES INTO
THE CANADIAN PRAIRIE. RATHER DIFFUSE SURFACE FRONT OVER THE EASTERN
PLAINS HAS BEEN GRADUALLY DRIFTING BACK EASTWARD THIS MORNING...WITH
WARMER/DRIER AIR MASS SPREADING EAST FROM THE MOUNTAINS ACROSS THE
I-25 CORRIDOR. OVERALL...WINDS TODAY LOOK LESS THAN THE PAST FEW
DAYS AS MID LEVEL FLOW DECREASES AND SURFACE GRADIENT RELAXES. FAR
SOUTHEAST PLAINS...MAINLY BACA COUNTY...COULD GET FAIRLY WINDY AHEAD
OF LEE SURFACE TROUGH...THOUGH RH REMAINS JUST ABOVE 15 PERCENT AND
WILL REFRAIN FROM ISSUING A FIRE WX HIGHLIGHT. WITH THIN PLUME OF
MID LEVEL MOISTURE OVER THE AREA ONCE AGAIN...EXPECT ANOTHER ROUND
OF MAINLY ISOLATED AFTERNOON AND EVENING THUNDERSTORMS...WITH BEST
CHANCES ALONG AND EAST OF A TRINIDAD TO LA JUNTA TO EADS
LINE...WHERE DEWPOINTS HOLD IN THE 40S AND CAPES PUSH ABOVE 1000
J/KG. SOME CONCERN ABOUT LOW RH AND BRIEFLY GUSTY WINDS OVER
TELLER/EL PASO COUNTIES THIS AFTERNOON...AS SUCCESSIVE RUNS OF THE
HRRR/NAM HAVE TRENDED DRIER AND WINDIER THE PAST FEW HOURS. IN
FACT...LATEST HRRR DROPS DEWPOINTS INTO THE TEENS OVER NORTHERN EL
PASO COUNTY BY EARLY AFTERNOON...WHICH SUGGESTS FAIRLY DEEP
MIXING...THOUGH MODEL SURFACE/BL WINDS NEVER GET MUCH ABOVE 15
KNOTS. MAX TEMPS CONTINUE ON THE HOT SIDE...VERY SIMILAR TO
YESTERDAY. OVERNIGHT...CONVECTION LINGERS IN THE DEEPER MOISTURE
OVER THE FAR EASTERN PLAINS PAST SUNSET...THOUGH MOST AREAS SHOULD
SEE TSRA END BY MIDNIGHT AS POTENTIAL MCS LIFTS NORTHEAST INTO NEB.
SURFACE FRONT SHOULD GET A SOUTHWESTWARD SHOVE BY DEPARTING
CONVECTION...WITH LOW LEVEL MOISTURE SLOSHING BACK TO THE I-25
CORRIDOR AND EASTERN MOUNTAINS BY EARLY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 343 AM MDT FRI JUN 14 2013
SOME CHANGES TO THE EXTENDED FOR THE WEEKEND INTO EARLY NEXT WEEK.
MODEL SOLUTIONS HAVE AN UPPER LEVEL RIDGE ACROSS THE ROCKIES
SATURDAY THROUGH TUESDAY...WITH SEVERAL DISTURBANCES MOVING ACROSS THE
REGION UNDER THE RIDGE. THE MAIN MODEL DIFFERENCES ARE IN THE
AMOUNT AND TYPE OF CONVECTION THAT MAY BE POSSIBLE ACROSS THE
PLAINS. MOISTURE WILL BE THE BIGGEST COMPLICATION AND WILL
DETERMINE HOW MUCH PRECIPITATION FALLS WITH THUNDERSTORM ACTIVITY.
MOISTURE STILL LOOKS MODEST ON SATURDAY AND MODEL SOLUTIONS ARE
HINTING THAT THUNDERSTORM ACTIVITY MAY BE LIMITED. MODELS DEVELOP
THUNDERSTORMS OVER THE MOUNTAINS BY SATURDAY AFTERNOON...WITH SOME
MOVEMENT OVER THE PALMER DIVIDE AND RATON MESA THROUGH THE
EVENING. LIGHTNING AND STRONG WIND GUSTS...POSSIBLY AS HIGH WAS 50
MPH...WILL BE THE MAIN THREATS...WITH VERY LITTLE PRECIPITATION
ACTUALLY FALLING.
MODELS A BIT MORE IMPRESSIVE WITH PRECIPITATION CHANCES SUNDAY
THROUGH TUESDAY. MOISTURE WILL ADVECT NORTHWARD OUT OF THE DESERT
SOUTHWEST WHICH SHOULD LEAD TO MORE WIDESPREAD SHOWER AND
THUNDERSTORM ACTIVITY. EXPECT THUNDERSTORMS TO DEVELOP BY LATE
MORNING EACH DAY OVER THE MOUNTAINS...AND SPREAD EAST INTO THE
I-25 CORRIDOR BY THE AFTERNOON. THE GFS IS MOST IMPRESSIVE
DEVELOPING MCS EVENTS THAT PUSH EAST ACROSS THE PLAINS THROUGH THE
OVERNIGHT PERIODS. THIS WOULD BRING LOCALLY HEAVY RAINFALL UNDER
THE STORM SYSTEMS. FOR NOW HAVE WIDESPREAD LOW POPS ACROSS THE
REGION AND HOPEFULLY THE REGION SEES SOME BENEFICIAL RAINFALL.
AN UPPER LEVEL LOW WILL MOVE INTO THE PACIFIC NORTHWEST BY
WEDNESDAY WHICH WILL SPREAD STRONG DRY SOUTHWEST FLOW ACROSS THE
ROCKIES. THIS WILL LEAD TO DRY AND HOT CONDITIONS ACROSS COLORADO
ALONG WITH INCREASED RISK OF DANGEROUS FIRE WEATHER CONDITIONS.
AREAS OVER THE CONTINENTAL DIVIDE...SAN LUIS VALLEY AND EASTERN
MOUNTAINS WILL LIKELY SEE THE DANGEROUS CONDITIONS BY WEDNESDAY
AFTERNOON WHICH WILL SPREAD EAST ACROSS THE PLAINS FOR THURSDAY
AND FRIDAY. WE WILL CONTINUE TO MONITOR THE SITUATION FOR MID TO
LATE NEXT WEEK IN REGARDS TO FIRE WEATHER. MOZLEY
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1103 AM MDT FRI JUN 14 2013
KALS...ISOLATED HIGH BASED STORMS WILL DEVELOP OVER THE
SURROUNDING MOUNTAINS DURING THE AFTERNOON AND EARLY EVENING.
THREAT OF ANY CONVECTION NEAR KALS IS LOW AND DID NOT PUT ANY IN
TAFS. HOWEVER...OUTFLOWS FROM THE STORMS COULD AFFECT KALS.
KCOS AND KPUB...CLOUDS WILL GRADUALLY DISSIPATE...AND ANTICIPATE
CONVECTION IN THE VICINITY OF BOTH SITES DURING THE AFTERNOON AND
EARLY EVENING. NEARBY CONVECTION COULD PRODUCE GUSTY OUTFLOWS WHICH
MAY IMPACT TAF SITES. CURRENT TAFS HAVE A COLD FRONT PASSING
AROUND SUNRISE SATURDAY. HOWEVER...OUTFLOW FROM FRIDAY EVENING
CONVECTION COULD RESULT IN AN EARLIER FRONTAL PASSAGE. --PGW--
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...PJC
SHORT TERM...PETERSEN
LONG TERM...MOZLEY
AVIATION...PGW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1115 AM MDT FRI JUN 14 2013
.UPDATE...
ISSUED AT 916 AM MDT FRI JUN 14 2013
UPDATED THE GRIDS TO INCREASE CLOUD COVER ACROSS THE AREA OVER THE
NEXT FEW HOURS. -PJC
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM MDT FRI JUN 14 2013
SOUTHWEST FLOW ALOFT CONTINUES OVER THE AREA TODAY AND TONIGHT...AS
STRONG UPPER TROUGH LIFTS NORTHEAST FROM THE NORTHERN ROCKIES INTO
THE CANADIAN PRAIRIE. RATHER DIFFUSE SURFACE FRONT OVER THE EASTERN
PLAINS HAS BEEN GRADUALLY DRIFTING BACK EASTWARD THIS MORNING...WITH
WARMER/DRIER AIR MASS SPREADING EAST FROM THE MOUNTAINS ACROSS THE
I-25 CORRIDOR. OVERALL...WINDS TODAY LOOK LESS THAN THE PAST FEW
DAYS AS MID LEVEL FLOW DECREASES AND SURFACE GRADIENT RELAXES. FAR
SOUTHEAST PLAINS...MAINLY BACA COUNTY...COULD GET FAIRLY WINDY AHEAD
OF LEE SURFACE TROUGH...THOUGH RH REMAINS JUST ABOVE 15 PERCENT AND
WILL REFRAIN FROM ISSUING A FIRE WX HIGHLIGHT. WITH THIN PLUME OF
MID LEVEL MOISTURE OVER THE AREA ONCE AGAIN...EXPECT ANOTHER ROUND
OF MAINLY ISOLATED AFTERNOON AND EVENING THUNDERSTORMS...WITH BEST
CHANCES ALONG AND EAST OF A TRINIDAD TO LA JUNTA TO EADS
LINE...WHERE DEWPOINTS HOLD IN THE 40S AND CAPES PUSH ABOVE 1000
J/KG. SOME CONCERN ABOUT LOW RH AND BRIEFLY GUSTY WINDS OVER
TELLER/EL PASO COUNTIES THIS AFTERNOON...AS SUCCESSIVE RUNS OF THE
HRRR/NAM HAVE TRENDED DRIER AND WINDIER THE PAST FEW HOURS. IN
FACT...LATEST HRRR DROPS DEWPOINTS INTO THE TEENS OVER NORTHERN EL
PASO COUNTY BY EARLY AFTERNOON...WHICH SUGGESTS FAIRLY DEEP
MIXING...THOUGH MODEL SURFACE/BL WINDS NEVER GET MUCH ABOVE 15
KNOTS. MAX TEMPS CONTINUE ON THE HOT SIDE...VERY SIMILAR TO
YESTERDAY. OVERNIGHT...CONVECTION LINGERS IN THE DEEPER MOISTURE
OVER THE FAR EASTERN PLAINS PAST SUNSET...THOUGH MOST AREAS SHOULD
SEE TSRA END BY MIDNIGHT AS POTENTIAL MCS LIFTS NORTHEAST INTO NEB.
SURFACE FRONT SHOULD GET A SOUTHWESTWARD SHOVE BY DEPARTING
CONVECTION...WITH LOW LEVEL MOISTURE SLOSHING BACK TO THE I-25
CORRIDOR AND EASTERN MOUNTAINS BY EARLY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 343 AM MDT FRI JUN 14 2013
SOME CHANGES TO THE EXTENDED FOR THE WEEKEND INTO EARLY NEXT WEEK.
MODEL SOLUTIONS HAVE AN UPPER LEVEL RIDGE ACROSS THE ROCKIES
SATURDAY THROUGH TUESDAY...WITH SEVERAL DISTURBANCES MOVING ACROSS THE
REGION UNDER THE RIDGE. THE MAIN MODEL DIFFERENCES ARE IN THE
AMOUNT AND TYPE OF CONVECTION THAT MAY BE POSSIBLE ACROSS THE
PLAINS. MOISTURE WILL BE THE BIGGEST COMPLICATION AND WILL
DETERMINE HOW MUCH PRECIPITATION FALLS WITH THUNDERSTORM ACTIVITY.
MOISTURE STILL LOOKS MODEST ON SATURDAY AND MODEL SOLUTIONS ARE
HINTING THAT THUNDERSTORM ACTIVITY MAY BE LIMITED. MODELS DEVELOP
THUNDERSTORMS OVER THE MOUNTAINS BY SATURDAY AFTERNOON...WITH SOME
MOVEMENT OVER THE PALMER DIVIDE AND RATON MESA THROUGH THE
EVENING. LIGHTNING AND STRONG WIND GUSTS...POSSIBLY AS HIGH WAS 50
MPH...WILL BE THE MAIN THREATS...WITH VERY LITTLE PRECIPITATION
ACTUALLY FALLING.
MODELS A BIT MORE IMPRESSIVE WITH PRECIPITATION CHANCES SUNDAY
THROUGH TUESDAY. MOISTURE WILL ADVECT NORTHWARD OUT OF THE DESERT
SOUTHWEST WHICH SHOULD LEAD TO MORE WIDESPREAD SHOWER AND
THUNDERSTORM ACTIVITY. EXPECT THUNDERSTORMS TO DEVELOP BY LATE
MORNING EACH DAY OVER THE MOUNTAINS...AND SPREAD EAST INTO THE
I-25 CORRIDOR BY THE AFTERNOON. THE GFS IS MOST IMPRESSIVE
DEVELOPING MCS EVENTS THAT PUSH EAST ACROSS THE PLAINS THROUGH THE
OVERNIGHT PERIODS. THIS WOULD BRING LOCALLY HEAVY RAINFALL UNDER
THE STORM SYSTEMS. FOR NOW HAVE WIDESPREAD LOW POPS ACROSS THE
REGION AND HOPEFULLY THE REGION SEES SOME BENEFICIAL RAINFALL.
AN UPPER LEVEL LOW WILL MOVE INTO THE PACIFIC NORTHWEST BY
WEDNESDAY WHICH WILL SPREAD STRONG DRY SOUTHWEST FLOW ACROSS THE
ROCKIES. THIS WILL LEAD TO DRY AND HOT CONDITIONS ACROSS COLORADO
ALONG WITH INCREASED RISK OF DANGEROUS FIRE WEATHER CONDITIONS.
AREAS OVER THE CONTINENTAL DIVIDE...SAN LUIS VALLEY AND EASTERN
MOUNTAINS WILL LIKELY SEE THE DANGEROUS CONDITIONS BY WEDNESDAY
AFTERNOON WHICH WILL SPREAD EAST ACROSS THE PLAINS FOR THURSDAY
AND FRIDAY. WE WILL CONTINUE TO MONITOR THE SITUATION FOR MID TO
LATE NEXT WEEK IN REGARDS TO FIRE WEATHER. MOZLEY
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1103 AM MDT FRI JUN 14 2013
KALS...ISOLATED HIGH BASED STORMS WILL DEVELOP OVER THE
SURROUNDING MOUNTAINS DURING THE AFTERNOON AND EARLY EVENING.
THREAT OF ANY CONVECTION NEAR KALS IS LOW AND DID NOT PUT ANY IN
TAFS. HOWEVER...OUTFLOWS FROM THE STORMS COULD AFFECT KALS.
KCOS AND KPUB...CLOUDS WILL GRADUALLY DISSIPATE...AND ANTICIPATE
CONVECTION IN THE VICINITY OF BOTH SITES DURING THE AFTERNOON AND
EARLY EVENING. NEARBY CONVECTION COULD PRODUCE GUSTY OUTFLOWS WHICH
MAY IMPACT TAF SITES. CURRENT TAFS HAVE A COLD FRONT PASSING
AROUND SUNRISE SATURDAY. HOWEVER...OUTFLOW FROM FRIDAY EVENING
CONVECTION COULD RESULT IN AN EARLIER FRONTAL PASSAGE. --PGW--
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...PJC
SHORT TERM...PETERSEN
LONG TERM...MOZLEY
AVIATION...PGW
AREA FORECAST DISCUSSION
NWS LINCOLN IL
124 PM CDT FRI JUN 14 2013
.DISCUSSION...
ISSUED 124 PM CDT FRI JUN 14 2013
ISSUED MINOR UPDATE TO ADD A STRIPE OF 50 POPS TO THE FAR
SOUTHWEST CWA THIS AFTERNOON PRIMARILY AFFECTING RUSHVILLE TO
JACKSONVILLE AND WEST. CLUSTER OF SHOWERS AND EMBEDDED TSTMS HAS
NOW EDGED EAST OF THE MISSISSIPPI RIVER...AND ALTHOUGH IR IMAGERY
SHOWS CLOUD TOPS BEGINNING TO WARM...FEEL SYSTEM HAS ENOUGH
ORGANIZATION TO GRAZE THE CORNER OF THE CWA BEFORE DISSIPATING
EARLY THIS EVENING.
25
&&
.AVIATION...
ISSUED 1240 PM CDT FRI JUN 14 2013
VFR CONDITIONS EXPECTED OUTSIDE OF THUNDERSTORMS NEXT 24 HRS.
FIRST IN A SERIES OF TSTM COMPLEXES TO AFFECT THE MIDWEST OVER THE
NEXT COUPLE DAYS...IS SHIFTING EAST ALONG THE IA/MO BORDER. WITH
SFC RIDGE AXIS AND DRIER AIR STILL OVER CENTRAL IL FEEL MUCH OF
THIS WILL DISSIPATE AS IT PUSHES EAST OF THE MS RIVER THIS
AFTERNOON...LEAVING A VEIL OF HIGH CLOUDS OVER THE TERMINALS INTO
THIS EVENING. MOST MODEL GUIDANCE SUPPORTS ANOTHER COMPLEX
DEVELOPING OVER IA TONIGHT AND SHIFTS E/SE INTO NORTHERN AND
CENTRAL IA SATURDAY MORNING...IN A WEAKENING MODE AS LOW LEVEL JET
SUPPORT WEAKENS AFTER 12Z. THUS HAVE MOST CONFIDENCE IN THIS
ACTIVITY AFFECTING PIA...WHILE FARTHER SITES TO THE SOUTHEAST JUST
HAVE VCTS THROUGH THE REMAINDER OF THE MORNING. LIGHT/VRB WINDS
UNDER THE RIDGE AXIS THIS AFTERNOON WILL GRADUALLY COME AROUND TO
THE SOUTHEAST THIS EVENING BUT REMAIN LIGHT UNDER 10 KTS
OVERNIGHT. HIGHER SPEEDS OF 10+ KTS ARE EXPECTED AFTER 12Z SAT
AS GRADIENT DEVELOPS AHEAD OF A LOW PRESSURE WAVE SHIFTING ACROSS
IA.
25
&&
.PREV DISCUSSION...
ISSUED 1041 AM CDT FRI JUN 14 2013
15Z SURFACE MAP PLACED A RIDGE AXIS FROM LK SUPERIOR SOUTH THROUGH
CENTRAL IL AND INTO THE LOWER MISSISSIPPI VALLEY. THIS PROVIDED
LIGHT WINDS ALONG WITH MOSTLY SUNNY SKIES AND MILD
TEMPS/DEWPOINTS. UPSTREAM CONVECTION OVER CENTRAL IA/NRN MO
DEVELOPED AHEAD OF SHORTWAVE IN EASTERN NEB WHICH WAS TOPPING THE
UPPER RIDGE. THIS COMPLEX OF STORMS WAS BEING MAINTAINED FROM THE
SOUTHWEST BY A HIGH THETA-E FEED OF MOISTURE-RICH AIR FROM EASTERN
KS. THIS ACTIVITY SHOULD TEND TO DIMINISH AS IT SHIFTS EAST THIS
AFTERNOON AWAY FROM BEST SUPPORT AND INTO DRIER AIR ASSOCIATED
WITH THE LINGERING RIDGE. MOST HI-RES GUIDANCE SUPPORTS THIS IDEA
WITH THE HRRR BEING A NOTABLE EXCEPTION...BRINGING SCATTERED T-STORMS
INTO WEST CENTRAL IL AFTER 21Z. WILL KEEP A DRY FORECAST ACROSS
THE WEST FOR NOW BUT MONITOR TRENDS FOR THE LATE AFTERNOON.
OTHERWISE...SKIES TO BE MOSTLY SUNNY OVER THE EAST WITH INCREASING
HIGH CLOUDS OVER THE WESTERN CWA. HIGHS ON TRACK TO BE A COUPLE
DEGREES COOLER THAN YESTERDAY DUE TO SHALLOWER MIXING DEPTH UNDER
RIDGE AND ASSOCIATED LIGHTER WIND REGIME.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1241 PM CDT FRI JUN 14 2013
.DISCUSSION...
ISSUED 1041 AM CDT FRI JUN 14 2013
15Z SURFACE MAP PLACED A RIDGE AXIS FROM LK SUPERIOR SOUTH THROUGH
CENTRAL IL AND INTO THE LOWER MISSISSIPPI VALLEY. THIS PROVIDED
LIGHT WINDS ALONG WITH MOSTLY SUNNY SKIES AND MILD
TEMPS/DEWPOINTS. UPSTREAM CONVECTION OVER CENTRAL IA/NRN MO
DEVELOPED AHEAD OF SHORTWAVE IN EASTERN NEB WHICH WAS TOPPING THE
UPPER RIDGE. THIS COMPLEX OF STORMS WAS BEING MAINTAINED FROM THE
SOUTHWEST BY A HIGH THETA-E FEED OF MOISTURE-RICH AIR FROM EASTERN
KS. THIS ACTIVITY SHOULD TEND TO DIMINISH AS IT SHIFTS EAST THIS
AFTERNOON AWAY FROM BEST SUPPORT AND INTO DRIER AIR ASSOCIATED
WITH THE LINGERING RIDGE. MOST HI-RES GUIDANCE SUPPORTS THIS IDEA
WITH THE HRRR BEING A NOTABLE EXCEPTION...BRINGING SCATTERED T-STORMS
INTO WEST CENTRAL IL AFTER 21Z. WILL KEEP A DRY FORECAST ACROSS
THE WEST FOR NOW BUT MONITOR TRENDS FOR THE LATE AFTERNOON.
OTHERWISE...SKIES TO BE MOSTLY SUNNY OVER THE EAST WITH INCREASING
HIGH CLOUDS OVER THE WESTERN CWA. HIGHS ON TRACK TO BE A COUPLE
DEGREES COOLER THAN YESTERDAY DUE TO SHALLOWER MIXING DEPTH UNDER
RIDGE AND ASSOCIATED LIGHTER WIND REGIME.
&&
.AVIATION...
ISSUED 1240 PM CDT FRI JUN 14 2013
VFR CONDITIONS EXPECTED OUTSIDE OF THUNDERSTORMS NEXT 24 HRS.
FIRST IN A SERIES OF TSTM COMPLEXES TO AFFECT THE MIDWEST OVER THE
NEXT COUPLE DAYS...IS SHIFTING EAST ALONG THE IA/MO BORDER. WITH
SFC RIDGE AXIS AND DRIER AIR STILL OVER CENTRAL IL FEEL MUCH OF
THIS WILL DISSIPATE AS IT PUSHES EAST OF THE MS RIVER THIS
AFTERNOON...LEAVING A VEIL OF HIGH CLOUDS OVER THE TERMINALS INTO
THIS EVENING. MOST MODEL GUIDANCE SUPPORTS ANOTHER COMPLEX
DEVELOPING OVER IA TONIGHT AND SHIFTS E/SE INTO NORTHERN AND
CENTRAL IA SATURDAY MORNING...IN A WEAKENING MODE AS LOW LEVEL JET
SUPPORT WEAKENS AFTER 12Z. THUS HAVE MOST CONFIDENCE IN THIS
ACTIVITY AFFECTING PIA...WHILE FARTHER SITES TO THE SOUTHEAST JUST
HAVE VCTS THROUGH THE REMAINDER OF THE MORNING. LIGHT/VRB WINDS
UNDER THE RIDGE AXIS THIS AFTERNOON WILL GRADUALLY COME AROUND TO
THE SOUTHEAST THIS EVENING BUT REMAIN LIGHT UNDER 10 KTS
OVERNIGHT. HIGHER SPEEDS OF 10+ KTS ARE EXPECTED AFTER 12Z SAT
AS GRADIENT DEVELOPS AHEAD OF A LOW PRESSURE WAVE SHIFTING ACROSS
IA.
25
&&
.PREV DISCUSSION...
ISSUED 330 AM CDT FRI JUN 14 2013
SHORT TERM...TODAY THROUGH MONDAY NIGHT
WILL USE A BLEND OF THE 00Z MODELS FOR THIS FORECAST WITH ONE MORE
NICE DAY TODAY WITH PARTLY TO MOSTLY SUNNY SKIES THEN BECOMING MORE
UNSETTLED THIS WEEKEND INTO MON BEFORE DRIER AND COOLER WEATHER
RETURNS TUE/WED. MET AND MAV GUIDANCE TEMPS SIMILAR THROUGH SUNDAY
THOUGH DID GO A BIT WARMER FOR HIGHS TODAY SINCE TEMPS HAVE BEEN
RUNNING ABOVE GUIDANCE TEMPS PAST FEW DAYS AND EXPECTING A FAIR
AMOUNT OF SUNSHINE YET TODAY. SPC CONTINUES SLIGHT RISK OF SEVERE
STORMS IN DAY2 OUTLOOK FOR SAT NW HALF OF CWA AND WILL NEED TO
ADDRESS THIS.
1023 MB CANADIAN HIGH PRESSURE NORTH OF LAKE SUPERIOR OVER CENTRAL
ONTARIO WAS RIDGING SOUTHWARD INTO THE MS VALLEY AND PROVIDING
NEARLY CLEAR SKIES OVER CENTRAL AND EASTERN IL WITH A FEW PATCHES
OF HIGH CLOUDS OVER WEST CENTRAL IL. COOLER TEMPS WERE IN THE
UPPER 50S AND LOWER 60S WITH MORE COMFORTABLE DEWPOINTS IN THE LOW
TO MID 50S WITH LIGHT WINDS.
MODELS WEAKEN HIGH PRESSURE OVER CENTRAL ONTARIO SSE INTO LOWER MI
AND OHIO AT 1019 MB THIS EVENING AS UPPER LEVEL HEIGHTS RISE A BIT
OVER IL AS UPPER LEVEL TROF OVER THE ATLANTIC STATES PULLS FURTHER
AWAY FROM IL. SCATTERED CUMULUS CLOUDS TO DEVELOP BY MIDDAY WITH
INCREASING HIGH CLOUDS ESPECIALLY IL RIVER VALLEY WHERE SKIES
BECOME PARTLY SUNNY THIS AFTERNOON...AND MOSTLY SUNNY OVER EASTERN
IL. HIGHS GENERALLY IN THE LOWER 80S WITH AREAS FROM I-74 NE
CLOSER TO 80F AS ENE WINDS LESS THAN 10 MPH PREVAIL TODAY.
MOST AREAS SHOULD STAY DRY YET THIS EVENING WITH JUST SMALL
CHANCES OF SHOWERS AND THUNDERSTORMS MOVING INTO THE IL RIVER
VALLEY LATER THIS EVENING. THEN INCREASING CHANCES OF SHOWERS AND
THUNDERSTORMS OVERNIGHT FROM I-55 NW WITH LIKELY POPS NW OF THE IL
RIVER LATE TONIGHT. THIS DUE TO MCS TO RIDE OVER TOP OF UPPER
LEVEL RIDGE OVER THE EASTERN PLAINS AND MOVE FROM IA INTO
CENTRAL/NW IL OVERNIGHT INTO SAT MORNING. EASTERN AND SE IL SHOULD
STAY DRY THROUGH THE NIGHT. LOWS TONIGHT IN THE LOWER 60S AND COOLEST
OVER EAST CENTRAL IL. SPC KEEPS SLIGHT RISK OVER CENTRAL AND
WESTERN IA TONIGHT.
BETTER CHANCES OF CONVECTION SAT OVER CENTRAL AND NORTHERN AREAS
WHILE JUST SLIGHT CHANCE IN SE IL SAT AFTERNOON. MCS TO WEAKEN
OVER CENTRAL IL SAT MORNING BUT SCATTERED THUNDERSTORMS TO
REDEVELOP IN UNSTABLE AIR MASS SAT AFTERNOON AND CONTINUE SAT NIGHT
WHEN YET ANOTHER MCS TO IMPACT PARTS OF CENTRAL/NORTHERN IL. SPC
HAS SLIGHT CHANCE FROM RANTOUL TO SPRINGFIELD NW LATER SAT AFTERNOON
AND SAT NIGHT WITH 15% RISK OF DAMAGING WIND GUSTS AND LARGE HAIL
POSSIBLE.
FRONTAL BOUNDARY TO PUSH SOUTHWARD THROUGH CENTRAL/SE IL SUNDAY
AND STALL FOR A TIME EARLY NEXT WEEK BEFORE PUSHING FURTHER SOUTH
LATER MON AND MON NIGHT. HAVE HIGHER CHANCES OF SHOWERS AND
THUNDERSTORMS OVER SOUTHERN HALF CWA SUNDAY INTO MONDAY. SPC HAS
5% RISK OF SEVERE STORMS ON SUNDAY OVER CENTRAL/SE IL. CONVECTION
CHANCES TO DIMINISH FROM NW TO SE LATER MON INTO MONDAY EVENING.
LONG TERM...TUESDAY THROUGH THURSDAY
CANADIAN HIGH PRESSURE SETTLING INTO THE GREAT LAKES REGION BY
TUE TO RETURN DRY AND COOLER AND LESS HUMID WEATHER TUE AND WED.
CONVECTION CHANCES RETURN TO THE MS VALLEY BY THU BUT MODELS
DIFFER ON TIMING OF RETURNING CONVECTION CHANCES TO IL AND STAYED
CLOSE TO ALLBLEND POPS WHICH ARE JUST SLIGHT OVER WESTERN AREAS
THU.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1246 PM CDT FRI JUN 14 2013
.UPDATE...
ISSUED AT 1212 PM CDT FRI JUN 14 2013
APPEARS THE MOIST AIR IS WINNING OUT AS THE SMALL MCS THAT WAS IN
SW IA EARLIER THIS MORNING HAS SHIFTED INTO SE IA AND EXTREME NORTHEAST
MO. HAVE MADE A QUICK UPDATE TO THE GRIDS TO INCREASE POPS TO
LIKELY IN OUR SOUTHWEST CWA INTO THIS AFTERNOON. NONE OF THE
MODELS INCLUDING THE MESO MODELS INDICATED THIS MCS MOVING INTO
THE DVN CWA SO WILL CONTINUE TO NOWCAST AND UPDATE AS NEEDED.
UPDATE ISSUED AT 1033 AM CDT FRI JUN 14 2013
THUNDERSTORMS WERE OCCURRING IN SW IA AND NW MO ON THE NOSE OF A
LOW LEVEL JET AND STRONG MOISTURE GRADIENT...AND ON THE EDGE OF A
STRONG CAP. 850 MB DEWPOINT AT KTOP WAS +18C BUT DRIER AIR WAS NOTED
FARTHER TO THE NORTHEAST WITH KMPX -4C AND KDVN +7. THE BETTER
FORCING WILL REMAIN WEST AND SOUTHWEST OF THE DVN CWA BUT ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS WILL OCCUR IN OUR WESTERN
CWA LATE THIS MORNING INTO THE AFTERNOON HOURS.
UPDATE ISSUED AT 642 AM CDT FRI JUN 14 2013
RADAR SHOWS THE CONVECTION IN CENTRAL IOWA CONTINUES BUT IS
RAPIDLY WEAKENING AS IT MOVES INTO DRIER AIR AND AWAY FROM THE
BETTER SUPPORT. RAP TRENDS CONTINUE TO SHOW A WEAK BUT RESPECTABLE
THETA E GRADIENT WHICH IS HELPING TO MAINTAIN THE CONVECTION.
BASED ON RADAR AND RAP TRENDS SOME OF THIS CONVECTION WILL GET
INTO THE WESTERN CWFA THIS MORNING AS LIGHT SHOWERS OR SPRINKLES
BEFORE DISSIPATING.
WATER VAPOR AND THE RAP SHOW TWO VORT MAXES CURRENTLY MOVING
ACROSS NEBRASKA. THESE FEATURES WILL DRIVE THE DIURNAL CONVECTION
THIS AFTERNOON THAT WILL EVENTUALLY EVOLVE INTO ANOTHER NOCTURNAL
MCS LATE TONIGHT. ..08..
&&
.SYNOPSIS...
ISSUED AT 308 AM CDT FRI JUN 14 2013
06Z SFC ANALYSIS HAS A HIGH RUNNING FROM LAKE SUPERIOR INTO THE
LOWER MISSISSIPPI VALLEY. LOWS WERE IN SOUTHEAST MONTANA AND
SOUTHEAST COLORADO. THE MAIN SYNOPTIC FRONT RAN FROM SOUTHWEST
KANSAS INTO THE DEEP SOUTH. DEW POINTS WERE IN THE 60S AND 70S FROM
THE CENTRAL PLAINS INTO THE DEEP SOUTH WITH 40S AND 50S ACROSS THE
GREAT LAKES AND UPPER MISSISSIPPI VALLEY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 308 AM CDT FRI JUN 14 2013
THE MCS AND LIFT TOOLS INDICATE THE CURRENT CONVECTION FROM
SOUTHWEST MN INTO NORTHERN IOWA IS ASSOCIATED WITH A THETA E
GRADIENT AND VORT MAX. THIS CONVECTION WILL SLOWLY DISSIPATE AS IT
MOVES AWAY FROM THE BETTER MOISTURE AND INTO THE RIDGE. THUS THE
MORNING HOURS WILL BE DRY WITH AN INCREASE IN CLOUD COVER.
HOWEVER...THE CLOUD COVER WILL SLOWLY THIN AS IT HITS THE RIDGE SO
THERE SHOULD BE A RESPECTABLE AMOUNT OF SUNSHINE TO HELP WARM UP.
RAP TRENDS ALONG WITH THE MCS AND LIFT TOOLS INDICATE THE VORT MAX
MOVING THROUGH SOUTHERN NEBRASKA WILL PROBABLY BE THE MECHANISM TO
GENERATE DIURNAL CONVECTION THIS AFTERNOON. THIS CONVECTION SHOULD
DEVELOP OR MOVE INTO THE WESTERN CWFA AROUND MID AFTERNOON AND
SLOWLY OVERSPREAD THE WESTERN HALF OF THE CWFA THROUGH LATE
AFTERNOON.
TONIGHT...THE MCS AND LIFT TOOLS INDICATE THE DIURNAL CONVECTION IS
EXPECTED TO EVOLVE INTO ANOTHER NOCTURNAL MCS ACROSS THE AREA.
CONVECTION SHOULD REMAIN ISOLATED TO SCATTERED UNTIL CLOSER TO
MIDNIGHT WHEN THE LLJ VEERS INTO THE CWFA. AT THIS TIME UPSCALE
GROWTH AND AN INCREASE IN AREAL COVERAGE ACROSS THE CWFA WILL BE
SEEN. PWATS ARE EXPECTED TO BE OVER 1.5 INCHES SO THERE WOULD BE A
THREAT OF HEAVY RAIN IF STORMS MOVE OVER THE SAME AREA. THE GROUND
IS REASONABLY DRY SO THIS INITIAL ROUND OF RAIN SHOULD NOT CAUSE
MUCH IN THE WAY OF PROBLEMS. ..08..
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 308 AM CDT FRI JUN 14 2013
INITIAL FOCUS IS ON THUNDERSTORM POTENTIAL FOR SATURDAY THAT WILL
HAVE A RISK FOR BOTH SEVERE STORMS AND HEAVY RAINFALL. TRANSITION TO
NW FLOW TO THEN BRING COOLER AND DRIER WEATHER FOR AT LEAST THE
FIRST HALF OF NEXT WEEK.
NOCTURNAL MCS WILL LIKELY BE ON-GOING SATURDAY MORNING...WHERE
MODELS ARE IN GENERAL AGREEMENT DEPICTING LOW PRESSURE NEAR OMAHA
WITH A WARM...OR INITIALLY STATIONARY FRONT REACHING EAST ALONG THE
IA/MO BORDER. ALL ARE SUGGESTING A RIDGE TOPPING SHORTWAVE THAT WILL
PUSH THROUGH DURING THE DAY...WHICH SENDS THE SURFACE LOW
EAST-NORTHEAST ACROSS THE FORECAST AREA AND NUDGES THE SURFACE
BOUNDARY NORTHWARD. ON THE WARM SIDE OF THIS BOUNDARY...MODEL CAPES
ARE ROUGHLY IN THE RANGE OF 3500 TO OVER 4000 J/KG WITH BULK SHEAR
VALUES AROUND 40 TO 45 KTS...SUFFICIENT FOR SEVERE STORMS AND
SUPERCELLS ESPECIALLY ALONG THE BOUNDARY IN THE AFTERNOON INTO
EVENING. SPC HAS THE ENTIRE FORECAST AREA IN A SLIGHT RISK FOR DAY
2. MUCH WILL DEPEND ON THE TIMING OF THE EXITING OR DISSIPATING
OVERNIGHT MCS AND RELATED BOUNDARIES AND CLOUD COVER. FOR NOW...WILL
CONTINUE A BROAD-BRUSH APPROACH WITH LIKELY POPS FOR THUNDERSTORMS
OVER THE ENTIRE AREA. HIGHS WILL LIKELY BE LIMITED TO THE UPPER 70S
ACROSS THE NORTH...WHILE THE SOUTH SHOULD AT LEAST PUSH INTO THE 80S
WITH DEWPOINTS INTO THE 70S...DEPENDING ON TRENDS WITH CLOUD COVER AND
FRONTAL TIMING. ELEVATED SW FLOW OF 15 TO 30 KTS WILL ADVECT A HIGH
PW AIRMASS...AROUND 1.5 TO 1.8 OR 150 PERCENT OF NORMAL OVER THE
ENTIRE AREA...THAT WILL SUPPORT HEAVY RAINFALL IN HP TYPE SUPERCELLS OR
WHERE STORMS TRAIN ALONG BOUNDARIES. THE RESULTING FLASH FLOODING
THREAT WILL BE HIGHLY DEPENDENT ON RAINFALL COVERAGE AND AMOUNTS
FROM THE PREVIOUS EVENT. FOR NOW...HAVE WIDESPREAD QPF AMOUNTS OF A
QUARTER TO HALF INCH...BUT FULLY EXPECT STORM SCALE TOTALS OF 1 TO 2
INCHES.
SATURDAY NIGHT...A STRONGER SHORTWAVE...INITIALLY OVER THE TX BEND
REGION AT 00Z...IS SHOWN RIDING NORTH AND THEN SWEEPING EAST ACROSS
THE FORECAST AREA IN THE FIRST HALF OF THE NIGHT...PROVIDING RENEWED
FOCUS FOR LIKELY ANOTHER MCS AND POSSIBLE HEAVY RAINFALL AND LIKELY
POPS ARE MAINTAINED. THIS SYSTEM IS EXPECTED TO SUPPRESS THE FRONTAL
BOUNDARY BACK TO JUST SOUTH OF THE FORECAST AREA SUNDAY. THE CLOSE
PROXIMITY OF THIS BOUNDARY...AND A STRONG UPPER SHORTWAVE THEN
ADVANCING FROM THE NW WILL KEEP SHOWERS AND THUNDERSTORMS IN THE
FORECAST THROUGH MONDAY...BUT THE HEAVY RAINFALL THREAT WILL BE
DIMINISHED. A NW FLOW AND HIGH PRESSURE THEN SUGGESTS DRY CONDITIONS
THROUGH AT LEAST WED WITH NEAR TO SLIGHTLY BELOW NORMAL
TEMPERATURES. MODEL CONSENSUS HAS CHANCES FOR SHOWERS AND
THUNDERSTORMS RETURNING TO THE FORECAST THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1242 PM CDT FRI JUN 14 2013
VFR CONDS THIS AFTERNOON WITH THUNDERSTORMS IN SOUTHEAST IA MOVING
TO THE SOUTHEAST. KBRL IS ON THE EDGE OF THE CLUSTER OF STORMS.
OTHERWISE...AT ALL TAF SITES SHOWERS AND THUNDERSTORMS WILL
ARRIVE THIS EVENING AND OVERNIGHT...THEN DIMINISH A BIT SATURDAY
MORNING. MVFR/BRIEF IFR CONDS CAN BE EXPECTED IN THE STRONGER
STORMS. SOUTHEAST WINDS AROUND 10 KNOTS OR LESS THIS AFTERNOON AND
TONIGHT THEN BECOMING SOUTH 10 TO 15 KNOTS ON SATURDAY.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...08
SHORT TERM...08
LONG TERM...SHEETS
AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1217 PM CDT FRI JUN 14 2013
.UPDATE...
ISSUED AT 1212 PM CDT FRI JUN 14 2013
APPEARS THE MOIST AIR IS WINNING OUT AS THE SMALL MCS THAT WAS IN
SW IA EARLIER THIS MORNING HAS SHIFTED INTO SE IA AND EXTREME NORTHEAST
MO. HAVE MADE A QUICK UPDATE TO THE GRIDS TO INCREASE POPS TO
LIKELY IN OUR SOUTHWEST CWA INTO THIS AFTERNOON. NONE OF THE
MODELS INCLUDING THE MESO MODELS INDICATED THIS MCS MOVING INTO
THE DVN CWA SO WILL CONTINUE TO NOWCAST AND UPDATE AS NEEDED.
UPDATE ISSUED AT 1033 AM CDT FRI JUN 14 2013
THUNDERSTORMS WERE OCCURRING IN SW IA AND NW MO ON THE NOSE OF A
LOW LEVEL JET AND STRONG MOISTURE GRADIENT...AND ON THE EDGE OF A
STRONG CAP. 850 MB DEWPOINT AT KTOP WAS +18C BUT DRIER AIR WAS NOTED
FARTHER TO THE NORTHEAST WITH KMPX -4C AND KDVN +7. THE BETTER
FORCING WILL REMAIN WEST AND SOUTHWEST OF THE DVN CWA BUT ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS WILL OCCUR IN OUR WESTERN
CWA LATE THIS MORNING INTO THE AFTERNOON HOURS.
UPDATE ISSUED AT 642 AM CDT FRI JUN 14 2013
RADAR SHOWS THE CONVECTION IN CENTRAL IOWA CONTINUES BUT IS
RAPIDLY WEAKENING AS IT MOVES INTO DRIER AIR AND AWAY FROM THE
BETTER SUPPORT. RAP TRENDS CONTINUE TO SHOW A WEAK BUT RESPECTABLE
THETA E GRADIENT WHICH IS HELPING TO MAINTAIN THE CONVECTION.
BASED ON RADAR AND RAP TRENDS SOME OF THIS CONVECTION WILL GET
INTO THE WESTERN CWFA THIS MORNING AS LIGHT SHOWERS OR SPRINKLES
BEFORE DISSIPATING.
WATER VAPOR AND THE RAP SHOW TWO VORT MAXES CURRENTLY MOVING
ACROSS NEBRASKA. THESE FEATURES WILL DRIVE THE DIURNAL CONVECTION
THIS AFTERNOON THAT WILL EVENTUALLY EVOLVE INTO ANOTHER NOCTURNAL
MCS LATE TONIGHT. ..08..
&&
.SYNOPSIS...
ISSUED AT 308 AM CDT FRI JUN 14 2013
06Z SFC ANALYSIS HAS A HIGH RUNNING FROM LAKE SUPERIOR INTO THE
LOWER MISSISSIPPI VALLEY. LOWS WERE IN SOUTHEAST MONTANA AND
SOUTHEAST COLORADO. THE MAIN SYNOPTIC FRONT RAN FROM SOUTHWEST
KANSAS INTO THE DEEP SOUTH. DEW POINTS WERE IN THE 60S AND 70S FROM
THE CENTRAL PLAINS INTO THE DEEP SOUTH WITH 40S AND 50S ACROSS THE
GREAT LAKES AND UPPER MISSISSIPPI VALLEY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 308 AM CDT FRI JUN 14 2013
THE MCS AND LIFT TOOLS INDICATE THE CURRENT CONVECTION FROM
SOUTHWEST MN INTO NORTHERN IOWA IS ASSOCIATED WITH A THETA E
GRADIENT AND VORT MAX. THIS CONVECTION WILL SLOWLY DISSIPATE AS IT
MOVES AWAY FROM THE BETTER MOISTURE AND INTO THE RIDGE. THUS THE
MORNING HOURS WILL BE DRY WITH AN INCREASE IN CLOUD COVER.
HOWEVER...THE CLOUD COVER WILL SLOWLY THIN AS IT HITS THE RIDGE SO
THERE SHOULD BE A RESPECTABLE AMOUNT OF SUNSHINE TO HELP WARM UP.
RAP TRENDS ALONG WITH THE MCS AND LIFT TOOLS INDICATE THE VORT MAX
MOVING THROUGH SOUTHERN NEBRASKA WILL PROBABLY BE THE MECHANISM TO
GENERATE DIURNAL CONVECTION THIS AFTERNOON. THIS CONVECTION SHOULD
DEVELOP OR MOVE INTO THE WESTERN CWFA AROUND MID AFTERNOON AND
SLOWLY OVERSPREAD THE WESTERN HALF OF THE CWFA THROUGH LATE
AFTERNOON.
TONIGHT...THE MCS AND LIFT TOOLS INDICATE THE DIURNAL CONVECTION IS
EXPECTED TO EVOLVE INTO ANOTHER NOCTURNAL MCS ACROSS THE AREA.
CONVECTION SHOULD REMAIN ISOLATED TO SCATTERED UNTIL CLOSER TO
MIDNIGHT WHEN THE LLJ VEERS INTO THE CWFA. AT THIS TIME UPSCALE
GROWTH AND AN INCREASE IN AREAL COVERAGE ACROSS THE CWFA WILL BE
SEEN. PWATS ARE EXPECTED TO BE OVER 1.5 INCHES SO THERE WOULD BE A
THREAT OF HEAVY RAIN IF STORMS MOVE OVER THE SAME AREA. THE GROUND
IS REASONABLY DRY SO THIS INITIAL ROUND OF RAIN SHOULD NOT CAUSE
MUCH IN THE WAY OF PROBLEMS. ..08..
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 308 AM CDT FRI JUN 14 2013
INITIAL FOCUS IS ON THUNDERSTORM POTENTIAL FOR SATURDAY THAT WILL
HAVE A RISK FOR BOTH SEVERE STORMS AND HEAVY RAINFALL. TRANSITION TO
NW FLOW TO THEN BRING COOLER AND DRIER WEATHER FOR AT LEAST THE
FIRST HALF OF NEXT WEEK.
NOCTURNAL MCS WILL LIKELY BE ON-GOING SATURDAY MORNING...WHERE
MODELS ARE IN GENERAL AGREEMENT DEPICTING LOW PRESSURE NEAR OMAHA
WITH A WARM...OR INITIALLY STATIONARY FRONT REACHING EAST ALONG THE
IA/MO BORDER. ALL ARE SUGGESTING A RIDGE TOPPING SHORTWAVE THAT WILL
PUSH THROUGH DURING THE DAY...WHICH SENDS THE SURFACE LOW
EAST-NORTHEAST ACROSS THE FORECAST AREA AND NUDGES THE SURFACE
BOUNDARY NORTHWARD. ON THE WARM SIDE OF THIS BOUNDARY...MODEL CAPES
ARE ROUGHLY IN THE RANGE OF 3500 TO OVER 4000 J/KG WITH BULK SHEAR
VALUES AROUND 40 TO 45 KTS...SUFFICIENT FOR SEVERE STORMS AND
SUPERCELLS ESPECIALLY ALONG THE BOUNDARY IN THE AFTERNOON INTO
EVENING. SPC HAS THE ENTIRE FORECAST AREA IN A SLIGHT RISK FOR DAY
2. MUCH WILL DEPEND ON THE TIMING OF THE EXITING OR DISSIPATING
OVERNIGHT MCS AND RELATED BOUNDARIES AND CLOUD COVER. FOR NOW...WILL
CONTINUE A BROAD-BRUSH APPROACH WITH LIKELY POPS FOR THUNDERSTORMS
OVER THE ENTIRE AREA. HIGHS WILL LIKELY BE LIMITED TO THE UPPER 70S
ACROSS THE NORTH...WHILE THE SOUTH SHOULD AT LEAST PUSH INTO THE 80S
WITH DEWPOINTS INTO THE 70S...DEPENDING ON TRENDS WITH CLOUD COVER AND
FRONTAL TIMING. ELEVATED SW FLOW OF 15 TO 30 KTS WILL ADVECT A HIGH
PW AIRMASS...AROUND 1.5 TO 1.8 OR 150 PERCENT OF NORMAL OVER THE
ENTIRE AREA...THAT WILL SUPPORT HEAVY RAINFALL IN HP TYPE SUPERCELLS OR
WHERE STORMS TRAIN ALONG BOUNDARIES. THE RESULTING FLASH FLOODING
THREAT WILL BE HIGHLY DEPENDENT ON RAINFALL COVERAGE AND AMOUNTS
FROM THE PREVIOUS EVENT. FOR NOW...HAVE WIDESPREAD QPF AMOUNTS OF A
QUARTER TO HALF INCH...BUT FULLY EXPECT STORM SCALE TOTALS OF 1 TO 2
INCHES.
SATURDAY NIGHT...A STRONGER SHORTWAVE...INITIALLY OVER THE TX BEND
REGION AT 00Z...IS SHOWN RIDING NORTH AND THEN SWEEPING EAST ACROSS
THE FORECAST AREA IN THE FIRST HALF OF THE NIGHT...PROVIDING RENEWED
FOCUS FOR LIKELY ANOTHER MCS AND POSSIBLE HEAVY RAINFALL AND LIKELY
POPS ARE MAINTAINED. THIS SYSTEM IS EXPECTED TO SUPPRESS THE FRONTAL
BOUNDARY BACK TO JUST SOUTH OF THE FORECAST AREA SUNDAY. THE CLOSE
PROXIMITY OF THIS BOUNDARY...AND A STRONG UPPER SHORTWAVE THEN
ADVANCING FROM THE NW WILL KEEP SHOWERS AND THUNDERSTORMS IN THE
FORECAST THROUGH MONDAY...BUT THE HEAVY RAINFALL THREAT WILL BE
DIMINISHED. A NW FLOW AND HIGH PRESSURE THEN SUGGESTS DRY CONDITIONS
THROUGH AT LEAST WED WITH NEAR TO SLIGHTLY BELOW NORMAL
TEMPERATURES. MODEL CONSENSUS HAS CHANCES FOR SHOWERS AND
THUNDERSTORMS RETURNING TO THE FORECAST THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 642 AM CDT FRI JUN 14 2013
CONVECTION IN CENTRAL IOWA WILL DISSIPATE THROUGH 18Z/14 AS IT
ENCOUNTERS DRIER AIR OVER EASTERN IOWA. VFR WX IS EXPECTED
THROUGH 00Z/15. TSRA WILL DEVELOP AFT 20Z/14 THAT WILL BECOME MORE
NUMEROUS ACROSS EASTERN IOWA/NORTHERN ILLINOIS AFT 00Z/15. AFT
00Z/15 VFR WX IS EXPECTED TO CONTINUE. HOWEVER...THE TSRA ARE
EXPECTED TO EVOLVE INTO A TSRA COMPLEX THAT MAY RESULT IN MVFR
CONDITIONS AFT 06Z/15. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...08
SHORT TERM...08
LONG TERM...SHEETS
AVIATION...08
AREA FORECAST DISCUSSION
NWS CARIBOU ME
554 PM EDT FRI JUN 14 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL CROSS THE AREA LATE THIS AFTERNOON AND EARLY
EVENING. A SECONDARY COLD FRONT WILL APPROACH FROM QUEBEC SATURDAY
AND CROSS THE REGION SATURDAY NIGHT. WEAK LOW PRESSURE FROM THE
GREAT LAKES WILL APPROACH FROM THE WEST LATER SUNDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
550 PM UPDATE: INCLUDED GUSTY WINDS AND SMALL HAIL AS FAR SOUTH AS
NORTHERN WASHINGTON COUNTY THROUGH 00Z AS RADAR INDICATING SOME OF THE
STORMS HAVE SOME HAIL W/REFLECTIVITY CORE ABOVE THE FREEZING LEVEL
OF 8500 FT. THIS MATCHES WELL W/THE LATEST LAPS AND RUC ANALYSIS
W/INSTABILITY AXIS SHIFTING FURTHER SOUTH.
PREVIOUS DISCUSSION:
LATEST RADAR REF SHOWS THE MOST IMPRESSIVE CNVCTV ACTIVITY OVR NE
ME AT THE MOMENT...BUT EVEN SO...TOPS HAVE GENERALLY NOT EXCEEDED
25 KFT FOR THE MOST PART. FCST SBCAPES INTO ERLY EVE WILL BE IN
THE 300 TO 600 J/KG RANGE...ENOUGH FOR GENERAL THUNDER...WITH
ISOLD SVR TSTMS SLIMLY POSSIBLE. THINKING IS THAT ACTIVITY NOW
SLIDING S (WITH FORWARD CORFIDI PROPAGATION OF 15 KT OR SO) TOWARD
CNTRL PTNS OF THE FA WILL STABILIZE SOMEWHAT DUE TO MID/HI CLD CVR
HANGING ON OVR THIS AND DOWNEAST AREAS FOR MUCH OF THE DAY.
THE CAPE ENVIRONMENT WILL CONTINUE FOR AREAS OF THE N NOT BEING
RAN OVR BY CURRENT CNVCTN UNTIL ERLY EVE...AFTERWHICH THE LOSS OF
HTG AND THE BUCKLING OF WEAK LLVL THETA-E RIDGE ACROSS THE N WILL
RESULT IN DISSIPATION OF ACTIVITY BY MID TO LATE EVE.
FOLLOWING THE UPPER LVL S/WV CROSSING THE FA FROM QB...LLVL COOL
ADVCN WILL BRING DRIER SFC DWPTS AND CLRG TO THE REGION LATE TNGT
AND ERLY SAT MORN. SAT WILL BEGIN MCLR...BUT ANOTHER S/WV ASSOCIATED
WITH A STRONG BUT TIGHT MID LVL VORTEX FROM HUDSON BAY TRACKING
ESE N OF THE FA INTO THE CAN MARITIMES WILL BRING SOME CLDNSS TO
THE FA BY AFTN AND PERHAPS ANOTHER CHC OF SHWRS AHEAD OF A
SECONDARY COLD FRONT SLATED TO ARRIVE INTO NW PTNS OF THE FA BY
SAT EVE. NW WIND GUSTS COULD REACH 25 TO 30 MPH MIDDAY AND AFTN
SAT DUE TO A STRONGER PRES GRAD AT THE SFC AND WINDS ALF.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
ANY SHOWERS THAT DEVELOP ON SATURDAY WILL QUICKLY SUBSIDE DURING THE
EVENING HOURS AS DAYTIME HEATING IS LOST. A WEAK SECONDARY FRONT
WILL TRAVERSE ACROSS THE REGION OVERNIGHT SATURDAY NIGHT, USHERING
IN MUCH DRIER AIR. AS SUCH, SATURDAY NIGHT WILL BE DRY AND COOL
UNDER PARTLY TO MOSTLY CLEAR SKIES. HOWEVER, RAIN RETURNS BY SUNDAY
AFTERNOON AS A WARM FRONT SLOWLY LIFTS TOWARD NORTHERN NEW ENGLAND.
THIS FRONT WILL CROSS THE PINE TREE STATE SUNDAY NIGHT AND STALL
SOMEWHERE OVER SOUTHERN QUEBEC/NORTHERN MAINE. ALTHOUGH THERE MAY BE
A BRIEF BREAK FROM THE RAIN SUNDAY NIGHT, IT RETURNS MONDAY AS A
WAVE OF LOW PRESSURE TRAVELS ALONG THE STALLED BOUNDARY. GIVEN THE
UNCERTAINTY ON EXACTLY HOW JUST HOW FAR NORTH THE WARM FRONT WILL
LIFT, IT IS HARD TO SAY HOW MUCH OF THE FORECAST AREA WILL BE IN THE
WARM SECTOR COME MONDAY. FOR THOSE AREAS THAT ARE ON THE SOUTHERN
SIDE OF THE FRONT, THUNDERSTORMS WILL BE POSSIBLE (AWAY FROM THE
COAST) AND TEMPERATURES WILL REACH INTO THE 70S. NORTH OF THE FRONT,
TEMPERATURES WILL REMAIN IN THE 60S AND THE PRECIPITATION WILL BE
MORE STRATIFORM IN NATURE WITH LIMITED INSTABILITY. CURRENT MODEL
GUIDANCE IS SPLIT ON THE FRONT`S POSITION (QUEBEC VS MAINE), SO HAVE
STAYED PRETTY CLOSE TO THE PREVIOUS FORECAST (WHICH LOOKED
REASONABLE) FOR CONSISTENCY. ALSO OPTED TO LEAVE ANY MENTION OF
THUNDER OUT OF THE FORECAST FOR NOW GIVEN THE UNCERTAINTY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
GUIDANCE IN REASONABLE AGREEMENT WITH TROUGH LOCATION ACROSS THE
GREAT LAKES. THE MAJOR DIFFERENCE RIGHT NOW IS THE TIMING. THE
00/06Z GFS BRINGS A SURFACE LOW TO THE NORTH WITH FRONTAL BOUNDARY
EXTENDING SOUTH FOR TUESDAY AFTERNOON. THE 00Z ECMWF BRINGS THE
SURFACE LOW SOUTH WITH A SHORTWAVE RIDING THROUGH THE LARGER UPPER
LEVEL LOW BUT IS A BIT SLOWER WITH TIMING. EITHER SCENARIO WOULD
BRING DECENT SHOT OF PRECIP ACROSS THE REGION FOR TUESDAY AND
TUESDAY NIGHT. THE LATEST 12Z GFS STILL HAS SAME TIMING WITH
INTIAL LOW. THE BIGGEST CHANGE WOULD BE THE DEVELOPMENT OF A
COASTAL LOW FOR WEDNESDAY IN RESPONSE TO ANOTHER SHORTWAVE THAT
DEVELOPS NEAR THE GREAT LAKES. THE 00Z CMC DOES INTRODUCE THE
SURFACE LOW WEDNESDAY BUT MUCH FURTHER SOUTH THAN THE 12Z GFS.
CONDITIONS DO IMPROVE LATER IN THE FORECAST PERIOD AS HIGH
PRESSURE MOVES EAST. TEMPERATURES THROUGH THE PERIOD STAYING NEAR
NORMAL.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
NEAR TERM: VFR XPCTD ALL SITES THRU SAT...XCPT BRIEFLY MVFR IN HVY
RNFL LATE THIS AFTN AND EVE IN ANY TSTM OR HEAVIER SHWR.
SHORT TERM: VFR CONDITIONS ARE EXPECTED SATURDAY NIGHT INTO
SUNDAY MORNING, BUT MVFR CEILINGS WILL BE POSSIBLE SUNDAY
AFTERNOON THROUGH MONDAY AS RAIN SHOWERS SPREAD INTO THE REGION.
ISOLATED THUNDERSTORMS WILL BE POSSIBLE MONDAY AFTERNOON, MAINLY
AT KBHB AND KBGR. MVFR/VFR CONDITIONS AND UNSETTLED WEATHER WILL
CONTINUE INTO MID WEEK.
&&
.MARINE...
NEAR TERM: NO HDLNS ANTICIPATED ATTM. THE ONLY CONCERN IS SWELL
COMING BACK BACK AROUND THE W END OF NOVA SCOTIA BY SAT AS THE
DEPARTING LOW MOVES INTO THE OPEN N ATLC. USED WW3 WITH SWAN NAM
SMOOTHED NEAR THE COASTLINE TO REDUCE COASTLINE WV HTS TO AROUND
1 TO 2 FT.
SHORT TERM: A WEAK FRONT WILL PASS ACROSS THE WATERS SATURDAY NIGHT,
WITH ANOTHER TO COME LATE SUNDAY. THIS WILL KEEP UNSETTLED WEATHER
AROUND INTO EARLY NEXT WEEK. HOWEVER, CONDITIONS ARE EXPECTED TO
REMAIN BELOW SMALL CRAFT CRITERIA, SO NO HEADLINES ARE ANTICIPATED.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT/VJN
SHORT TERM...HASTINGS
LONG TERM...JORDAN
AVIATION...HEWITT/VJN/HASTINGS
MARINE...HEWITT/VJN/HASTINGS
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1128 AM MDT Fri Jun 14 2013
.UPDATE...
Current satellite imagery shows upper level trof extending from
northern Alberta to southern Idaho with the trof axis slightly east
of the Rocky Mtn Front. Moisture plume along/behind the trof axis
will bring one more round of showers and isolated to scattered
thunderstorms over central and southwest MT this aftn. Have slightly
increased chances of precipitation from Great Falls north to US/Can
border for today as morning model runs indicating enough lift and
instability there to promote better precip coverage. Although
severe storms are not expected for our region, will be keeping a
close eye on storm development as cooling aloft may bring slightly
higher chance for some storms to produce small hail. Gradual
clearing still expected this evening with dry/warmer conditions
beginning tomorrow.
Waranauskas
&&
.DISCUSSION...
Today through Sunday night...One more day of unsettled weather is in
store for the area. An upper level trof will move across the area
today bringing additional instability. A jet max rounding the upper
trof will aid in the development of showers and thunderstorms over
southwest Montana this morning. Both the models and HRRR analysis
indicate the development of storms over the southwest mountains this
morning and their subsequent movement north and east during the
afternoon. SPC has the entire county warning area under a general
thunderstorm outlook for today. Some storms may be strong but
widespread severe storms are not anticipated. Breezy westerly winds
will develop across the plains by late morning. Cooler air has moved
into southwest Montana and some snow is possible above 7500 feet
today. Convective activity ends by late afternoon with rising
heights as an upper ridge begins to build over western Montana.
Saturday and Sunday will be dry with warming temperatures. Afternoon
readings will be below seasonal averages today but warm to near to
slightly above seasonal averages this weekend. Emanuel
Sunday night through Friday...Models continue to be in good
agreement, but the overall progression of next week`s low pressure
system from the Pacific Ocean is about 24 hours slower than the
previous runs. Will address the changes below. An upper level ridge
of high pressure will linger over Montana through Monday night. The
airmass will warm to between 5 and 10 degrees above seasonal
averages, but weak steering winds aloft will keep the threat for
isolated thunderstorm activity over the higher terrain. The
aforementioned weather system will then deepen and move onto the
Pacific coast on Tuesday. The increasingly moist and unstable
southwesterly flow aloft ahead of the system will bring an
increasing chance of showers and thunderstorms mainly to the western
half of Montana. The flow aloft will also pump warmer air into the
area, causing temperatures to warm to between 10 and 15 degrees
above normal. As the system moves into the Pacific Northwest on
Wednesday, the flow aloft will become more southerly, unstable, and
diffluent. This, in turn, will bring a much better chance for
showers and thunderstorms to the area, especially over north
central/central Montana. Forecast CAPE values increase to between
1000 and 2000 J/kg Wednesday afternoon/evening, which hints at the
potential for a round of strong to possibly severe thunderstorms.
Would like to see run-to-run consistency with this feature before
mentioning severe potential in Hazardous Weather Outlook. Forecast
models differ with exact movement of this system beyond Wednesday.
GFS model moves the system into southern Alberta and Saskatchewan by
Friday, while the ECMWF model keeps the system over the Pacific
Northwest. The GEM is slow with movement of the system (moving it
over Montana), but it weakens the system. With this discrepancy,
have kept the chance for showers/thunderstorms near climatology and
will look to refine the details when the models come into better
agreement. Regardless, the models all bring a cold front through the
area Wednesday night, which should cool temperatures back to between
5 and 10 degrees below normal for Thursday through Friday and bring
breezy westerly winds to the area. Coulston
&&
.AVIATION...
Updated 1727Z.
An upper level low pressure trof will move east of the region and
high pressure will begin to build aloft. However, the airmass will
remain slightly unsettled through the afternoon and early evening.
Scattered showers and thunderstorms will develop although small hail
and strong, gusty winds are possible from thunderstorms. Westerly
surface winds will remain gusty through the afternoon and early
evening, as well. VFR conditions will prevail through the next 24
hours.
&&
.HYDROLOGY...
Point flood warnings remain in effect for the Big Sandy Creek near
Havre and Clear Creek near Chinook. Rain from recent thunderstorms
will keep water levels high in many creeks and streams. Drier
weather this weekend should result in gradually decreasing levels
into early next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 64 42 75 44 / 20 10 0 0
CTB 63 42 73 43 / 20 10 0 10
HLN 64 43 75 46 / 40 10 0 0
BZN 61 38 75 41 / 70 20 0 0
WEY 55 31 68 34 / 40 10 0 0
DLN 59 36 73 41 / 70 20 0 0
HVR 68 46 76 48 / 20 20 10 10
LWT 62 41 71 44 / 30 10 0 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
Flood Warnings continue until further notice for Big Sandy Creek
near Havre and Clear Creek near Chinook.
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1245 PM CDT FRI JUN 14 2013
.DISCUSSION...
HAVE AGAIN TWEAKED FORECAST THROUGH THE REMAINDER OF THE
AFTERNOON. A WARM FRONTAL FEATURE IS DEVELOPING ACROSS EASTERN
NEB...AND SATELLITE TRENDS INDICATE SOME CLEARING IS TAKING
PLACE...WITH TEMPS INTO THE 80S AND DEWPOINTS ALREADY BREACHING
70 IN SOUTHEAST NEB. THOUGH UPPER-LEVEL PATTERN IS FAIRLY
BENIGN...SURFACE CONVERGENCE SHOULD BE ENOUGH TO PROMPT
THUNDERSTORM DEVELOPMENT BEGINNING IN THE LATE AFTERNOON.
HOWEVER...DO THINK THAT UPPER-LEVEL FORCING IS WEAK ENOUGH THAT
SIGNIFICANT COVERAGE IS NOT EXPECTED BEFORE 00Z. HAVE BACKED
AFTERNOON POPS DOWN TO CHANCE/SCATTERED CATEGORY...WITH COVERAGE
WORDING...AND TIGHTENED LOCATION OF MOST LIKELY THUNDERSTORM
DEVELOPMENT.
MAYES
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
PREVAILING VFR CONDITIONS ARE EXPECTED THROUGH THE TAF CYCLE.
THUNDERSTORMS ARE LIKELY TO DEVELOP IN CENTRAL TO EASTERN NEBRASKA
BY AROUND 00Z AND PERSIST FOR SEVERAL HOURS. HAVE INCLUDED A TEMPO
MENTION AT ALL SITES FOR NOW WITH A BEST GUESS AT TIME WINDOW THAT
SITES WOULD BE AFFECTED BY STORMS. SHOULD ANY OF THE HEAVIER
STORMS MOVE OVER A TAF SITE...WOULD FORESEE POSSIBILITY FOR MVFR
TO IFR CONDITIONS FOR A SHORT TIME...BUT CONFIDENCE IS TOO LOW TO
INTRODUCE AT THIS TIME. IN WAKE OF STORMS...SHOULD SEE IMPROVING
CONDTIONS FOR OVERNIGHT AND MORNING. WINDS WILL SHIFT BY LATE
MORNING TO NORTHEASTERLY AT KOFK...AND NORTH/NORTHWESTERLY AT
KOMA/KLNK.
MAYES
&&
.PREV DISCUSSION... /ISSUED 951 AM CDT FRI JUN 14 2013/
DISCUSSION...
MADE A FEW UDPATES FOR ONGOING MORNING TRENDS. CONVECTION IS
SLIDING EASTWARD OUT OF WESTERN IOWA...AND AREA OF LIGHT SHOWERS
ALONG THE I-80 CORRIDOR BETWEEN SEWARD AND LINCOLN IS DISSIPATING.
HOWEVER...A NEW LINE OF SHOWERS AND ISOLATED THUNDER HAS CROPPED
UP FROM ALBION TO YANKTON. HAVE ADJUSTED POPS FOR THESE
TRENDS...AND DO EXPECT ACTIVITY TO FADE/MOVE OUT THROUGH THE
REMAINDER OF THE MORNING HOURS...WITH THUNDERSTORMS DEVELOPING
AGAIN LATER THIS AFTERNOON...AND A WINDOW OF DRY WEATHER BETWEEN.
MAYES
PREV DISCUSSION... /ISSUED 714 AM CDT FRI JUN 14 2013/
AVIATION...
12Z TAFS FOR KOMA...KLNK...KOFK.
VFR CEILINGS ARE FORECAST ACROSS MUCH OF THE AREA DURING THE
DAY...EXCEPT IN THE VICINITY OF THUNDERSTORMS WHERE CEILINGS CAN
BE EXPECTED TO BE MVFR. SOUTHERLY WINDS ARE FORECAST TO BECOME
GUSTY BY 18Z WITH GUSTS AS HIGH AS 25 KT. SHRA OVER THE FORECAST
AREA SHOULD DIMINISH BY MID MORNING AND THEN TSRA IS EXPECTED TO
DEVELOP...ESPECIALLY AFTER 21Z.
SMITH
PREV DISCUSSION... /ISSUED 340 AM CDT FRI JUN 14 2013/
DISCUSSION...
MAIN FORECAST CONCERN IS CONVECTION THIS MORNING...THEN AGAIN
THIS AFTERNOON AND TONIGHT...
LATEST WATER VAPOR IMAGERY AND RAP 500MB ANALYSIS SHOW A TROUGH AXIS
EXTENDING FROM LOW PRESSURE IN ALBERTA SOUTHWARD TOWARD NORTHERN
NEVADA. DOWNSTREAM...A HIGH PRESSURE RIDGE AXIS EXTENDS FROM THE
SOUTHERN PLAINS INTO CENTRAL MANITOBA. AN EMBEDDED WEAK SHORTWAVE
CONTINUES TO MOVE UP THE BACKSIDE OF THE RIDGE AND INTO CENTRAL
NEBRASKA. WIDELY SCATTERED THUNDERSTORMS CONTINUE IN ADVANCE OF
THIS SHORTWAVE AND THESE ARE SLOWLY MOVING EAST-NORTHEAST. MOST
LIKELY SCENARIO TO PLAY OUT SEEMS TO BE WHAT THE HRRR AND RAP
HAVE BEEN INDICATING AND THAT IS FOR THE CONVECTION ASSOCIATED
WITH THE ABOVE MENTIONED SHORTWAVE TO CONTINUE TO CLUSTER TOGETHER AND
DRIFT EAST ACROSS THE CWA THROUGH THE MORNING WHERE STRONG
ISENTROPIC UPGLIDE RESIDES. SOME OF THESE MAY CONTAIN MARGINALLY
SEVERE HAIL...AIDED BY A VEERED 35-45KT LOW LEVEL JET.
CLOUD COVER FROM MORNING CONVECTIVE ACTIVITY WILL LIKELY INHIBIT
STRONG HEATING INITIALLY. AS HIGH PLAINS SFC LOW PRESSURE SLIDES
EAST TODAY...A WARM FRONT WILL EXTEND WEST TO EAST ACROSS THE
FORECAST AREA BRINGING A RAPID WARM UP TO THE AREA THIS
AFTERNOON...ESPECIALLY IN OUR SOUTH. IN ADDITION...SFC DEWPOINTS
ARE PROGGED TO RISE INTO THE LOWER 70S BY AFTERNOON WHICH MAY BE A
BIT HIGH AND PUSHES FORECASTED SFC BASED CAPE VALUES INTO THE 4000
J/KG RANGE. WITH AN INCREASING SOUTHWEST LOW LEVEL JET EARLY IN
THE EVENING AIDING TSTMS...THINK BUSIEST TIMEFRAME IN TERMS OF ANY
SEVERE STORMS WILL BE FROM ABOUT 23Z-03Z NEAR THE SFC BOUNDARY.
THIS WILL MOST LIKELY LINGER INTO THE OVERNIGHT HOURS AS A
POSSIBLE MCS AS THE BOUNDARY REMAINS IN THE AREA. ALL THIS LIMITED
OF COURSE BY CAPPING INVERSION...ESPECIALLY THIS AFTERNOON.
WILL CONTINUE TO CARRY POPS THROUGH THE WEEKEND AS THE BOUNDARY
REMAINS OVER THE AREA ALTHOUGH DO NOT THINK WE WILL HAVE A
CONTINUOUS PERIOD OF THUNDERSTORMS THROUGHOUT THE ENTIRE WEEKEND.
WITH WESTERLY MID LEVEL FLOW...HIGHER POPS ARE WARRANTED WITH
THIS BOUNDARY EXTENDING OVER THE AREA.
NO CHANGES INTO THE LATER PERIODS WITH DRIER WEATHER ON TAP FOR
MONDAY AND TUESDAY AND A BIT MORE ACTIVE MID TO LATE WEEK.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1236 PM CDT FRI JUN 14 2013
.UPDATE...
ISSUED AT 1236 PM CDT FRI JUN 14 2013
TODAY WILL MARK THE 4TH DAY IN A ROW OF 100+ TEMPS AT PGH
/PHILLIPSBURG KS/.
HIGH TEMPS WERE INCREASED OVER MUCH OF S-CNTRL NEB WITH THE 11 AM
UPDATE. THE ONLY CHANGES WITH THIS ENHANCED SHORT-TERM FCST /ESTF/
UPDATE WERE TO GET THE HOURLY FCST BACK ON THE OBSERVED TREND LINE
AT A A COUPLE COOLER LOCATIONS. ALSO NUDGED WINDS UP A COUPLE KTS.
THE BULK OF THE AFTN-TNGT-SAT FCST WILL BE UPDATED AND IN ITS
PROBABLE FINAL FORM BY 130 PM IN AN EFFORT TO MONITOR SHORT-TERM
MESOSCALE TRENDS AS WE AWAIT CONVECTIVE INITIATION.
UPDATE ISSUED AT 1121 CDT FRI JUN 14 2013
THE WARM FRONT HAS BEEN REINFORCED BY TSTM ACTIVITY OVER THE LAST
12 HRS. IT LIES ROUGHLY FROM NEAR IMPERIAL-PHILLIPSBURG KS-KANSAS
CITY. EXPECT FRONT TO LIFT N. MEANWHILE...THE APPROACHING COOL
FRONT IS OVER THE PANHANDLE BACK TO NEAR DENVER.
IMPORTANT MESOSCALE PARAMETERS:
MLCAPE 2000-3500 J/KG.
EFFECTIVE SHEAR 25 KTS.
LCL HGTS 6-8K FT.
2-7 KM SHEAR VECTOR ORIENTATION: PARALLEL TO THE COOL FRONT.
0-3 KM SRH WILL BE E OF THE WARM FRONT...WHICH SHOULD BE E OF THE
FCST AREA BY THE TIME TSTMS ERUPT. THE SUPERCELL COMPOSITE
PARAMETER WILL ALSO BE GREATEST E OF THE WARM FRONT AS WELL.
BOTTOM LINE...MODERATE SHEAR...DRY SUB-CLOUD LAYER...AND SHEAR
ORIENTATION PARALLEL TO THE FRONT WILL RESULT IN OUTFLOW DOMINANT
MULTICELL TSTMS THAT WILL TEND TO ORGANIZE INTO LINES. THE PRIMARY
THREAT WILL BE DAMAGING MICROBURST WINDS UP TO 70 MPH /POSSIBLY
HIGHER/. INSTABILITY WILL BE SIGNIFICANT...BUT LIMITED SHEAR WILL
LIMIT THE LARGEST HAIL TO THE SIZE OF GOLF BALLS.
IF FOR SOME REASON THE COOLER/DENSE AIR PREVAILS...AND THE WARM
FRONT REMAINS OVER PART OF THE FCST AREA...SAY FROM ORD-GRAND
ISLAND-HEBRON...THEN LCL HGTS WILL BE LOWER AND SHEAR WILL BE
HIGHER AND WE`LL NEED TO WATCH FOR SUPERCELL/TORNADO POTENTIAL
OVER THE ERN FRINGE OF OUR FCST AREA. SINCE SUNSHINE IS OCCURRING
N OF THE FRONT...THIS IS A GOOD SIGN THAT THE FRONT SHOULD LIFT N
AND CLEAR THE FCST AREA.
UPDATE ISSUED AT 952 AM CDT FRI JUN 14 2013
OFF TO A BIT OF SLOW START DUE TO MONITORING RADAR THRU 830 AM.
THERE WERE A COUPLE OF NEAR-SVR STORMS THAT TRACKED FROM NEAR
HANSEN E ALONG THE HAMILTON-CLAY COUNTY LINE. WE SAW 50 DBZ UP TO
32K FT.
THE MRNG SHWRS/TSTMS WERE WARM FRONT GENERATED. THE HEAT WILL NOW
FOLLOW.
FCST HOURLY TEMPS WERE RUNNING WAY TOO WARM IN THE RAIN-COOLED
AREAS. SO SOME MAJOR ADJUSTMENTS HAVE BEEN MADE. CLEARING IS
HEADING E PER VIS SAT SO TEMPS SHOULD ROCKET UP. ALSO ADJUSTED
POPS AS SHWRS/TSTMS HAVE NEARLY CLEARED THE FCST AREA. POPS WERE
ALSO BLENDED WITH MULTIPLE HI-RES MODELS FROM 23Z-06Z TO COVER
TSTMS EXPECTED TO ERUPT.
FURTHER EVALUATION OF THE SITUATION WILL BE ON-GOING AND WE`LL
PROBABLY HAVE MORE IN AN AFD LATER THIS MRNG. 12Z SOUNDINGS ARE
SURPRISINGLY MOIST UP TO 850 MB. HOWEVER...WITH HIGHS OF 94-104F
AT 5 PM...SFC TEMP/DWPT SPREADS WILL STILL RESULT IN SUBSTANTIAL
DRYING BELOW CLOUD BASES THAT DEVELOP.
BASED ON BEST-VERIFYING HIGH TEMP GUIDANCE WE WILL PROBABLY BE
RAISING HIGH TEMPS SEVERAL DEGS IN THE TRI-CITIES AREA PENDING
FURTHER EVALUATION BEFORE NOON.
SLGT RISK CONTINUES FOR LATE THIS AFTN-EVNG.
PLEASE FOLLOW LATEST UPDATES FROM THE SPC VIA THEIR OUTLOOKS AND
MESOSCALE DISCUSSIONS...AND ALL FUTURE STATEMENTS/WATCHES/WARNINGS
FROM THIS OFFICE.
SKYWARN: BE ALERT FOR ACTIVATION IN THE 21Z-00Z TIME FRAME.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 413 AM CDT FRI JUN 14 2013
THE PRIMARY FORECAST CONCERN CENTERS AROUND THE CHANCE OF
THUNDERSTORMS EARLY THIS MORNING AND THEN AGAIN LATER THIS
AFTERNOON. SOME THUNDERSTORMS LATE THIS AFTERNOON AND EVENING WILL
LIKELY BE SEVERE.
THE FIRST ROUND OF THUNDERSTORMS HAVE BEEN WEAKENING AS THEY TRACK
EAST. THE HRRR SEEMS TO HAVE A GOOD HANDLE ON THESE STORMS AND
TRACKS THEM ALL THE WAY ACROSS OUR FORECAST AREA GENERALLY ALONG
THE INTERSTATE 80/HWY 6 CORRIDOR. CURRENT EXPECTATION IS THAT ALL
OF THESE THUNDERSTORMS WILL HAVE EITHER DECAYED OR BE EAST OF OUR
FORECAST AREA BY MID MORNING WITH DRY CONDITIONS FROM LATE
MORNING THROUGH MID AFTERNOON. THE HIGH CIRRUS LEFT OVER FROM THE
MORNING THUNDERSTORMS WILL THIN AND WE SHOULD SEE A GOOD DEAL OF
SUNSHINE TODAY HELPING TEMPERATURES SKY ROCKET. AN INCREASING
SOUTH WIND IN THE WARM SECTOR TODAY...WHICH WILL INCLUDE ALL OF
OUR FORECAST AREA EXCEPT MAYBE OUR FAR NORTHERN ZONES WILL ALSO
HELP TO GIVE TEMPERATURES A BOOST. EXPECT AFTERNOON HIGHS TO RANGE
FROM AROUND 90 IN OUR FAR NORTH AROUND ORD TO OVER 100 ACROSS MUCH
OF NORTH CENTRAL KANSAS.
THERE IS GOOD FORECAST MODEL AGREEMENT THAT AFTERNOON
THUNDERSTORMS WILL EVENTUALLY OVERCOME AN ELEVATED CAP
AND INITIATE ALONG A SFC FRONT THAT WILL STRETCH FROM NORTHEAST
NEBRASKA INTO SOUTH CENTRAL NEBRASKA AND NORTHWEST KANSAS. MLCAPE
VALUES ALONG THE FRONT WILL RANGE FROM 2000 TO 4000 J/KG MAKING
FOR A VERY UNSTABLE ATMOSPHERE. 0-6KM WIND SHEAR WILL BE MORE
MARGINAL AT 25 TO 35 KTS. THE COMBINATION OF STRONG
INSTABILITY...AT LEAST MARGINAL SHEAR...AND A FRONTAL BOUNDARY
SHOULD BE MORE THAN SUFFICIENT TO ALLOW FOR SEVERAL SEVERE
THUNDERSTORMS ACROSS OUR FORECAST AREA LATE THIS AFTERNOON AND
EVENING. EXPECT INITIATION WILL LIKELY BE AFTER 4 PM WITH THE
GREATEST SEVERE WEATHER THREAT IN THE 5 PM TO 10 PM TIME FRAME.
REDEVELOPMENT AND POSSIBLE TRAINING OF THUNDERSTORMS ALONG THE
FRONT WILL BE POSSIBLE LEADING TO LOCALIZED HEAVY RAIN. THE
HIGHEST CHANCE OF THUNDERSTORMS WILL GENERALLY BE NEAR HIGHWAY 30
FROM MERRICK COUNTY DOWN INTO GRAND ISLAND AND KEARNEY...AND THEN
SOUTHWEST INTO GOSPER AND FURNAS COUNTY. THE CHANCE OF
THUNDERSTORMS WILL DECREASE PRETTY FAST AS YOU HEAD SOUTHEAST OF
THIS CORRIDOR INTO NORTH CENTRAL KANSAS. THE PRIMARY SEVERE
WEATHER THREATS WILL BE LARGE HAIL TO THE SIZE OF GOLFBALLS AND
WIND GUSTS TO 70 MPH. WIND IS A BIG CONCERN DUE TO THE INVERTED V
FORECAST SOUNDING AND STEEP LAPSE RATES ALONG WITH THE OBVIOUSLY
HIGH CAPE. THE TORNADO THREAT WILL BE LIMITED DUE TO GENERALLY
WEAK LOW LEVEL SHEAR AND HIGHER LCL HEIGHTS. THE LIMITED TORNADO
THREAT WILL BE ACROSS OUR NORTHEASTERN CWA PRIMARY FOR THE KEARNEY
AND GRAND ISLAND AREAS AND POINTS NORTHEAST WHERE LCL HEIGHTS WILL
BE THE LOWEST AND THERE MIGHT BE SOME BACKING OF THE SFC WIND BY
EARLY EVENING...BUT AGAIN THIS IS ONLY A LIMITED THREAT WITH THE
PRIMARY THREATS TODAY BEING BIG HAIL AND STRONG THUNDERSTORM
WINDS.
THE CONVECTION WILL SLOWLY PUSH EAST TONIGHT AND AREAS ALONG AND
NORTH OF HIGHWAY 6 MAY ALSO SEE SOME ADDITIONAL THUNDERSTORM
REDEVELOPMENT DURING THE LATE EVENING HOURS AS THE LOW LEVEL JET
STRENGTHENS AND NOSES INTO OUR NEBRASKA ZONES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 413 AM CDT FRI JUN 14 2013
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
AN ACTIVE WEATHER PATTERN WILL BE FOUND ACROSS THE AREA THROUGH THIS
PERIOD. MODELS ARE SIMILAR IN THE MAIN FEATURES WITH SUBTLE
DIFFERENCES IN THE FINER DETAILS. SEVERAL UPPER LEVEL LOWS MOVE
THROUGH THE AREA DURING THE PERIOD AND EACH HAS THE POTENTIAL FOR
SOME THUNDERSTORMS. WITH THIS IN MIND THERE ARE CHANCES FOR
THUNDERSTORMS NEARLY EVERY PERIOD FOR PORTIONS OF THE AREA.
THE FIRST UPPER LEVEL LOW MOVES THROUGH THE AREA SATURDAY.
THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG A NEARLY STATIONARY
FRONT. THE QUESTION IS WHERE THIS FRONT WILL BE AND WHEN THE
THUNDERSTORMS DEVELOP. MODELS ARE SIMILAR THAT IT IS DRAPED ACROSS
THE CENTRAL TO SOUTHERN PART OF THE FORECAST AREA. HAVE KEPT CHANCES
ACROSS THE AREA WITH THUNDERSTORMS ALONG THE FRONT. THUNDERSTORM
CHANCES CONTINUE INTO SATURDAY NIGHT AS ANOTHER UPPER LEVEL WAVE
MOVES INTO THE AREA SATURDAY NIGHT AND THUNDERSTORMS ON THE HIGH
PLAINS START TO MOVE INTO THE AREA LATE SATURDAY NIGHT. THE NEXT
WAVE AFFECTS THE AREA SUNDAY AND SUNDAY NIGHT. THE BEST CHANCE FOR
THUNDERSTORMS WITH THIS ROUND WILL BE SUNDAY NIGHT IN THE SOUTHERN
PART OF THE FORECAST AREA.
THERE IS A BREAK ON MONDAY AS A SURFACE HIGH PRESSURE SYSTEM PUSHES
INTO THE AREA. THE BREAK IS SHORT LIVED FOR PORTIONS OF THE AREA.
ANOTHER UPPER LEVEL WAVE STARTS TO AFFECT THE CENTRAL HIGH PLAINS
MONDAY NIGHT THROUGH TUESDAY NIGHT...BUT WITH AN UPPER LEVEL RIDGE
ACROSS THE AREA AND THE SURFACE HIGH MOVING TO THE EAST THE STORMS
SHOULD BE MAINLY IN THE WESTERN PART OF THE FORECAST AREA.
WEDNESDAY THROUGH THURSDAY A SERIES OF UPPER LEVEL WAVES MOVE
THROUGH THE AREA AND BRING CHANCES FOR THUNDERSTORMS TO THE FORECAST
AREA AGAIN. MODELS HAVE A FEW DIFFERENCES IN THE TIMING OF THE
PRECIPITATION.
TEMPERATURES THROUGH THE PERIOD WILL BE MOSTLY IN THE 80S WITH A
LITTLE VARIATION UP AND DOWN THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1236 PM CDT FRI JUN 14 2013
THIS AFTN: VFR THOUGH SCT TSTMS DEVELOPING AROUND 22Z WITH POCKETS
OF IFR VSBYS. THREAT IS COVERED WITH VCTS UNTIL WE CAN BE MORE
CERTAIN THE TERMINAL WILL ACTUALLY BE HIT. THESE TSTMS WILL
CONTAIN GUSTY WINDS WITH 40 KTS LIKELY AND 50 KTS POSSIBLE.
OUTSIDE OF TSTMS...S WINDS WILL GUST UP TO 30 KTS THIS AFTN AND
THEN DIMINISH AND BECOME VARIABLE 10 KTS OR LESS AS A COOL FRONT
APPROACHES. THERE MAY BE A PRIMARY WIND DIRECTION...BUT
DISAGREEMENT AMONGST MODEL GUIDANCE PRECLUDES A DEFINITE DIRECTION.
TNGT: VFR OUTSIDE OF SCT TSTMS THEN THREAT DIMINISHES BUT MAY NOT
END AFTER 04Z. TOO MUCH UNCERTAINTY TO INCLUDE VCTS AFTER 04Z BUT
IT MAY EVENTUALLY NEED TO BE INCLUDED.
SAT: SCT TSTMS CONTINUE THOUGH EXPECT VFR MOST OF THE TIME.
CIG CONFIDENCE: AVERAGE
VSBY CONFIDENCE: HIGH OUTSIDE OF TSTMS
WX CONFIDENCE: LOW DUE TO TIMING/OCCURRENCE OF TSTMS
WIND CONFIDENCE: LOW
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1122 AM CDT FRI JUN 14 2013
.UPDATE...
ISSUED AT 1121 CDT FRI JUN 14 2013
THE WARM FRONT HAS BEEN REINFORCED BY TSTM ACTIVITY OVER THE LAST
12 HRS. IT LIES ROUGHLY FROM NEAR IMPERIAL-PHILLIPSBURG KS-KANSAS
CITY. EXPECT FRONT TO LIFT N. MEANWHILE...THE APPROACHING COOL
FRONT IS OVER THE PANHANDLE BACK TO NEAR DENVER.
IMPORTANT MESOSCALE PARAMETERS:
MLCAPE 2000-3500 J/KG.
EFFECTIVE SHEAR 25 KTS.
LCL HGTS 6-8K FT.
2-7 KM SHEAR VECTOR ORIENTATION: PARALLEL TO THE COOL FRONT.
0-3 KM SRH WILL BE E OF THE WARM FRONT...WHICH SHOULD BE E OF THE
FCST AREA BY THE TIME TSTMS ERUPT. THE SUPERCELL COMPOSITE
PARAMETER WILL ALSO BE GREATEST E OF THE WARM FRONT AS WELL.
BOTTOM LINE...MODERATE SHEAR...DRY SUB-CLOUD LAYER...AND SHEAR
ORIENTATION PARALLEL TO THE FRONT WILL RESULT IN OUTFLOW DOMINANT
MULTICELL TSTMS THAT WILL TEND TO ORGANIZE INTO LINES. THE PRIMARY
THREAT WILL BE DAMAGING MICROBURST WINDS UP TO 70 MPH /POSSIBLY
HIGHER/. INSTABILITY WILL BE SIGNIFICANT...BUT LIMITED SHEAR WILL
LIMIT THE LARGEST HAIL TO THE SIZE OF GOLF BALLS.
IF FOR SOME REASON THE COOLER/DENSE AIR PREVAILS...AND THE WARM
FRONT REMAINS OVER PART OF THE FCST AREA...SAY FROM ORD-GRAND
ISLAND-HEBRON...THEN LCL HGTS WILL BE LOWER AND SHEAR WILL BE
HIGHER AND WE`LL NEED TO WATCH FOR SUPERCELL/TORNADO POTENTIAL
OVER THE ERN FRINGE OF OUR FCST AREA. SINCE SUNSHINE IS OCCURRING
N OF THE FRONT...THIS IS A GOOD SIGN THAT THE FRONT SHOULD LIFT N
AND CLEAR THE FCST AREA.
UPDATE ISSUED AT 952 AM CDT FRI JUN 14 2013
OFF TO A BIT OF SLOW START DUE TO MONITORING RADAR THRU 830 AM.
THERE WERE A COUPLE OF NEAR-SVR STORMS THAT TRACKED FROM NEAR
HANSEN E ALONG THE HAMILTON-CLAY COUNTY LINE. WE SAW 50 DBZ UP TO
32K FT.
THE MRNG SHWRS/TSTMS WERE WARM FRONT GENERATED. THE HEAT WILL NOW
FOLLOW.
FCST HOURLY TEMPS WERE RUNNING WAY TOO WARM IN THE RAIN-COOLED
AREAS. SO SOME MAJOR ADJUSTMENTS HAVE BEEN MADE. CLEARING IS
HEADING E PER VIS SAT SO TEMPS SHOULD ROCKET UP. ALSO ADJUSTED
POPS AS SHWRS/TSTMS HAVE NEARLY CLEARED THE FCST AREA. POPS WERE
ALSO BLENDED WITH MULTIPLE HI-RES MODELS FROM 23Z-06Z TO COVER
TSTMS EXPECTED TO ERUPT.
FURTHER EVALUATION OF THE SITUATION WILL BE ON-GOING AND WE`LL
PROBABLY HAVE MORE IN AN AFD LATER THIS MRNG. 12Z SOUNDINGS ARE
SURPRISINGLY MOIST UP TO 850 MB. HOWEVER...WITH HIGHS OF 94-104F
AT 5 PM...SFC TEMP/DWPT SPREADS WILL STILL RESULT IN SUBSTANTIAL
DRYING BELOW CLOUD BASES THAT DEVELOP.
BASED ON BEST-VERIFYING HIGH TEMP GUIDANCE WE WILL PROBABLY BE
RAISING HIGH TEMPS SEVERAL DEGS IN THE TRI-CITIES AREA PENDING
FURTHER EVALUATION BEFORE NOON.
SLGT RISK CONTINUES FOR LATE THIS AFTN-EVNG.
PLEASE FOLLOW LATEST UPDATES FROM THE SPC VIA THEIR OUTLOOKS AND
MESOSCALE DISCUSSIONS...AND ALL FUTURE STATEMENTS/WATCHES/WARNINGS
FROM THIS OFFICE.
SKYWARN: BE ALERT FOR ACTIVATION IN THE 21Z-00Z TIME FRAME.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 413 AM CDT FRI JUN 14 2013
THE PRIMARY FORECAST CONCERN CENTERS AROUND THE CHANCE OF
THUNDERSTORMS EARLY THIS MORNING AND THEN AGAIN LATER THIS
AFTERNOON. SOME THUNDERSTORMS LATE THIS AFTERNOON AND EVENING WILL
LIKELY BE SEVERE.
THE FIRST ROUND OF THUNDERSTORMS HAVE BEEN WEAKENING AS THEY TRACK
EAST. THE HRRR SEEMS TO HAVE A GOOD HANDLE ON THESE STORMS AND
TRACKS THEM ALL THE WAY ACROSS OUR FORECAST AREA GENERALLY ALONG
THE INTERSTATE 80/HWY 6 CORRIDOR. CURRENT EXPECTATION IS THAT ALL
OF THESE THUNDERSTORMS WILL HAVE EITHER DECAYED OR BE EAST OF OUR
FORECAST AREA BY MID MORNING WITH DRY CONDITIONS FROM LATE
MORNING THROUGH MID AFTERNOON. THE HIGH CIRRUS LEFT OVER FROM THE
MORNING THUNDERSTORMS WILL THIN AND WE SHOULD SEE A GOOD DEAL OF
SUNSHINE TODAY HELPING TEMPERATURES SKY ROCKET. AN INCREASING
SOUTH WIND IN THE WARM SECTOR TODAY...WHICH WILL INCLUDE ALL OF
OUR FORECAST AREA EXCEPT MAYBE OUR FAR NORTHERN ZONES WILL ALSO
HELP TO GIVE TEMPERATURES A BOOST. EXPECT AFTERNOON HIGHS TO RANGE
FROM AROUND 90 IN OUR FAR NORTH AROUND ORD TO OVER 100 ACROSS MUCH
OF NORTH CENTRAL KANSAS.
THERE IS GOOD FORECAST MODEL AGREEMENT THAT AFTERNOON
THUNDERSTORMS WILL EVENTUALLY OVERCOME AN ELEVATED CAP
AND INITIATE ALONG A SFC FRONT THAT WILL STRETCH FROM NORTHEAST
NEBRASKA INTO SOUTH CENTRAL NEBRASKA AND NORTHWEST KANSAS. MLCAPE
VALUES ALONG THE FRONT WILL RANGE FROM 2000 TO 4000 J/KG MAKING
FOR A VERY UNSTABLE ATMOSPHERE. 0-6KM WIND SHEAR WILL BE MORE
MARGINAL AT 25 TO 35 KTS. THE COMBINATION OF STRONG
INSTABILITY...AT LEAST MARGINAL SHEAR...AND A FRONTAL BOUNDARY
SHOULD BE MORE THAN SUFFICIENT TO ALLOW FOR SEVERAL SEVERE
THUNDERSTORMS ACROSS OUR FORECAST AREA LATE THIS AFTERNOON AND
EVENING. EXPECT INITIATION WILL LIKELY BE AFTER 4 PM WITH THE
GREATEST SEVERE WEATHER THREAT IN THE 5 PM TO 10 PM TIME FRAME.
REDEVELOPMENT AND POSSIBLE TRAINING OF THUNDERSTORMS ALONG THE
FRONT WILL BE POSSIBLE LEADING TO LOCALIZED HEAVY RAIN. THE
HIGHEST CHANCE OF THUNDERSTORMS WILL GENERALLY BE NEAR HIGHWAY 30
FROM MERRICK COUNTY DOWN INTO GRAND ISLAND AND KEARNEY...AND THEN
SOUTHWEST INTO GOSPER AND FURNAS COUNTY. THE CHANCE OF
THUNDERSTORMS WILL DECREASE PRETTY FAST AS YOU HEAD SOUTHEAST OF
THIS CORRIDOR INTO NORTH CENTRAL KANSAS. THE PRIMARY SEVERE
WEATHER THREATS WILL BE LARGE HAIL TO THE SIZE OF GOLFBALLS AND
WIND GUSTS TO 70 MPH. WIND IS A BIG CONCERN DUE TO THE INVERTED V
FORECAST SOUNDING AND STEEP LAPSE RATES ALONG WITH THE OBVIOUSLY
HIGH CAPE. THE TORNADO THREAT WILL BE LIMITED DUE TO GENERALLY
WEAK LOW LEVEL SHEAR AND HIGHER LCL HEIGHTS. THE LIMITED TORNADO
THREAT WILL BE ACROSS OUR NORTHEASTERN CWA PRIMARY FOR THE KEARNEY
AND GRAND ISLAND AREAS AND POINTS NORTHEAST WHERE LCL HEIGHTS WILL
BE THE LOWEST AND THERE MIGHT BE SOME BACKING OF THE SFC WIND BY
EARLY EVENING...BUT AGAIN THIS IS ONLY A LIMITED THREAT WITH THE
PRIMARY THREATS TODAY BEING BIG HAIL AND STRONG THUNDERSTORM
WINDS.
THE CONVECTION WILL SLOWLY PUSH EAST TONIGHT AND AREAS ALONG AND
NORTH OF HIGHWAY 6 MAY ALSO SEE SOME ADDITIONAL THUNDERSTORM
REDEVELOPMENT DURING THE LATE EVENING HOURS AS THE LOW LEVEL JET
STRENGTHENS AND NOSES INTO OUR NEBRASKA ZONES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 413 AM CDT FRI JUN 14 2013
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
AN ACTIVE WEATHER PATTERN WILL BE FOUND ACROSS THE AREA THROUGH THIS
PERIOD. MODELS ARE SIMILAR IN THE MAIN FEATURES WITH SUBTLE
DIFFERENCES IN THE FINER DETAILS. SEVERAL UPPER LEVEL LOWS MOVE
THROUGH THE AREA DURING THE PERIOD AND EACH HAS THE POTENTIAL FOR
SOME THUNDERSTORMS. WITH THIS IN MIND THERE ARE CHANCES FOR
THUNDERSTORMS NEARLY EVERY PERIOD FOR PORTIONS OF THE AREA.
THE FIRST UPPER LEVEL LOW MOVES THROUGH THE AREA SATURDAY.
THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG A NEARLY STATIONARY
FRONT. THE QUESTION IS WHERE THIS FRONT WILL BE AND WHEN THE
THUNDERSTORMS DEVELOP. MODELS ARE SIMILAR THAT IT IS DRAPED ACROSS
THE CENTRAL TO SOUTHERN PART OF THE FORECAST AREA. HAVE KEPT CHANCES
ACROSS THE AREA WITH THUNDERSTORMS ALONG THE FRONT. THUNDERSTORM
CHANCES CONTINUE INTO SATURDAY NIGHT AS ANOTHER UPPER LEVEL WAVE
MOVES INTO THE AREA SATURDAY NIGHT AND THUNDERSTORMS ON THE HIGH
PLAINS START TO MOVE INTO THE AREA LATE SATURDAY NIGHT. THE NEXT
WAVE AFFECTS THE AREA SUNDAY AND SUNDAY NIGHT. THE BEST CHANCE FOR
THUNDERSTORMS WITH THIS ROUND WILL BE SUNDAY NIGHT IN THE SOUTHERN
PART OF THE FORECAST AREA.
THERE IS A BREAK ON MONDAY AS A SURFACE HIGH PRESSURE SYSTEM PUSHES
INTO THE AREA. THE BREAK IS SHORT LIVED FOR PORTIONS OF THE AREA.
ANOTHER UPPER LEVEL WAVE STARTS TO AFFECT THE CENTRAL HIGH PLAINS
MONDAY NIGHT THROUGH TUESDAY NIGHT...BUT WITH AN UPPER LEVEL RIDGE
ACROSS THE AREA AND THE SURFACE HIGH MOVING TO THE EAST THE STORMS
SHOULD BE MAINLY IN THE WESTERN PART OF THE FORECAST AREA.
WEDNESDAY THROUGH THURSDAY A SERIES OF UPPER LEVEL WAVES MOVE
THROUGH THE AREA AND BRING CHANCES FOR THUNDERSTORMS TO THE FORECAST
AREA AGAIN. MODELS HAVE A FEW DIFFERENCES IN THE TIMING OF THE
PRECIPITATION.
TEMPERATURES THROUGH THE PERIOD WILL BE MOSTLY IN THE 80S WITH A
LITTLE VARIATION UP AND DOWN THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 556 AM CDT FRI JUN 14 2013
SHOWERS AND THUNDERSTORMS WILL TRACK THROUGH KGRI EARLY THIS
MORNING WITH DRY WEATHER EXPECTED BY LATE MORNING THROUGH EARLY
AFTERNOON. THE FRONT WILL SINK TO AROUND KGRI BY MID AFTERNOON AND
THEN STALL OUT RESULTING IN FAIRLY LIGHT AND SHIFTY WINDS. WILL
STILL HAVE TO WATCH OUT FOR GUSTY THUNDERSTORM WINDS DURING THE
LATE AFTERNOON AND EVENING HOURS WITH ANY THUNDERSTORMS THAT
REDEVELOP.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
257 PM CDT FRI JUN 14 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 257 PM CDT FRI JUN 14 2013
MAIN CONCERN FOR THE SHORT TERM WILL BE THUNDERSTORMS ACROSS THE
NORTHWEST THIS EVENING. SATELLITE AND THE RAP MODEL SHOW A MID
LEVEL IMPULSE THAT WILL TRACK THROUGH NORTHEAST MONTANA INTO
NORTHWEST NORTH DAKOTA THIS EVENING. WILL ADD A CHANCE FOR
THUNDERSTORMS FOR THE EVENING HOURS. TO THE EAST...A COLD FRONT
WAS MAKING ITS WAY ACROSS CENTRAL NORTH DAKOTA. STILL BELIEVE
THERE WILL BE A CHANCE FOR CONVECTIVE INITIATION ACROSS THE EAST
CENTRAL TONIGHT. AFTER SUNRISE SATURDAY...BELIEVE ITS REASONABLE
FOR ALL THE PRECIPITATION TO BE NORTH AND EAST OF THE REGION .
WILL GO DRY FOR SATURDAY IN GENERAL SUBSIDENCE ON THE SOUTH AND
WEST SIDE OF THE UPPER LOW WHICH WILL BE IN CANADA.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 257 PM CDT FRI JUN 14 2013
NO SIGNIFICANT WEATHER TO HIGHLIGHT THE EXTENDED FORECAST WITH
BELOW NORMAL TEMPERATURES SUNDAY AND MONDAY TRANSITIONING TO NEAR
NORMAL VALUES THROUGH THE REMAINDER OF NEXT WEEK.
THE 12 UTC GUIDANCE SUITE IS IN GOOD AGREEMENT THROUGH WEDNESDAY
WITH A DIVERGENCE IN SOLUTIONS THURSDAY INTO FRIDAY. FOR
SUNDAY...A FILLING UPPER LEVEL LOW PROPAGATES SOUTHEAST OUT OF
CANADA WHICH SUPPORTS DIURNALLY DRIVEN ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS UNDER THE COLD CORE ALOFT. COOL HIGH
PRESSURE IN THE WAKE OF THIS SYSTEM FOR MONDAY SUGGESTS WIDESPREAD
HIGHS IN THE UPPER 60S AND LOWER 70S...ABOUT 7 TO 10 DEGREES BELOW
NORMAL. THEREAFTER...UPPER LEVEL RIDGING BUILDS ACROSS THE
NORTHERN PLAINS WITH A RETURN TO NORMAL HIGHS NEAR 80. UNCERTAINTY
INCREASES FOR CONVECTIVE CHANCES THURSDAY THROUGH FRIDAY IN REGARDS
TO THE PROPAGATION AND EVOLUTION OF THE UPPER LEVEL LOW COMING ON
SHORE TO THE PACIFIC NORTHWEST ON WEDNESDAY...AND HOW FAR EAST THE
LOW CAN PROPAGATE TO TURN TO THE UPPER LEVEL FLOW TO THE SOUTHWEST
ACROSS THE NORTHERN PLAINS. OVERALL...A BLEND OF THE 12 UTC
GUIDANCE SUITE WAS USED FOR MOST FIELDS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 257 PM CDT FRI JUN 14 2013
AT 2 PM CDT...SURFACE LOW PRESSURE ACROSS CENTRAL ALBERTA AND
SASKATCHEWAN HAD AN ASSOCIATED COLD FRONT PROGRESSING EAST
THROUGH CENTRAL NORTH DAKOTA. THE FRONT WILL BE THE FOCUS FOR
WIDELY SCATTERED THUNDERSTORMS IN THE JAMES RIVER VALLEY LATE THIS
AFTERNOON AND TONIGHT. AN UPPER LEVEL IMPULSE WILL BRING A CHANCE
OF THUNDERSTORMS NORTHWEST THIS EVENING. TIMING STILL UNCERTAIN
FOR THUNDERSTORMS SO AT THIS TIME WILL ONLY MENTION VCTS AT
KJMS/KISN. OTHERWISE VFR THROUGH TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...WAA
LONG TERM...AYD
AVIATION...WAA
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1109 AM CDT FRI JUN 14 2013
.UPDATE...
HAVE ADDED 10 POPS OVER THE FAR WESTERN COUNTIES THIS AFTERNOON FOR
ISOLATED CONVECTION POTENTIAL. A FEW LIGHT SHOWERS HAVE ALREADY
PASSED THROUGH MILLS AND LAMPASAS COUNTIES THIS MORNING AND
EXPECT SOME ADDITIONAL ACTIVITY DURING THE AFTERNOON HOURS. 75
&&
.AVIATION...
FOR THE 12Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE VALID
FORECAST PERIOD. LOW CHANCES OF SHOWERS AND THUNDERSTORMS LATE
THIS AFTERNOON AND ON SATURDAY ARE THE PRIMARY FORECAST CONCERNS.
A WEAK BUT LARGE UPPER LOW REMAINS IN PLACE NEAR DEL RIO...AND IS
EXPECTED TO MOVE NORTH THROUGHOUT THE DAY TODAY. AREA AIRPORTS ARE
EXPECTED TO REMAIN UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE
WHICH IS EXPECTED TO SLIDE SOUTHEAST OVER NORTH TX TODAY AND
SHOULD KEEP US DRY THROUGH SATURDAY MORNING.
WE WILL HAVE TO CAREFULLY MONITOR AREA TAF SITES FOR SHOWERS AND
THUNDERSTORMS DEVELOPING FURTHER EAST THAN MODEL GUIDANCE
EXPLICITLY FORECASTS THOUGH. MORNING RUNS OF THE RAP AND NAM BOTH
INDICATE THAT WE HAVE VERY LITTLE TO NO CAP REMAINING FOR STORMS
OVER THE DFW AREA AND WACO BY 23Z. THIS DOES NOT MEAN WE WILL GET
STORMS...HOWEVER ANY WEAK FORCING FOR ASCENT MAY BE ENOUGH TO SET
OFF SOME /SURPRISE/ SHOWER OR THUNDERSTORM ACTIVITY NEAR OR ON TOP
OF AREA AIRPORTS LATE THIS AFTERNOON INTO THE EVENING HOURS.
CHANCES OF THIS ARE TOO LOW TO DO ANYTHING BUT MENTION THE
POSSIBILITY IN THE DISCUSSION AT THIS TIME.
WE WILL HAVE A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS TOMORROW
AFTERNOON AT ALL AREA AIRPORTS AS THE UPPER LOW IS EXPECTED TO
MOVE NORTHEAST OVER NORTH TX. THE BEST CHANCE OF STORMS LOOKS TO
OCCUR AFTER 18Z AT THIS TIME...WHICH IS BEYOND THE CURRENT VALID
FORECAST PERIOD. CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 422 AM CDT FRI JUN 14 2013/
CHANGES IN THE WEATHER PATTERN SHOULD BRING SOME MUCH NEED RAIN TO
NORTH TEXAS THIS WEEKEND THROUGH EARLY NEXT WEEK. THE UPPER LEVEL
RIDGE THAT HAS DOMINATED NORTH TEXAS WEATHER THIS PAST WEEK WILL
MOVE EAST TO THE MISSISSIPPI VALLEY REGION WHILE A WEAK CLOSED LOW...
CURRENTLY CENTERED NEAR THE BIG BEND...OPENS UP AND MOVES EAST.
PRECIPITATION ASSOCIATED WITH THE UPPER LOW SHOULD REMAIN
WEST/SOUTHWEST OF NORTH TEXAS TODAY AS LARGE SCALE SUBSIDENCE
CONTINUES OVER THE REGION. HOWEVER...SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE ACROSS THE WESTERN SECTIONS OF
NORTH TEXAS AS EARLY AS SATURDAY MORNING AND ACROSS THE REMAINDER
OF REGION SATURDAY AFTERNOON AND EVENING. MARGINAL INSTABILITY AND
SHEAR WILL KEEP MOST IF NOT ALL STORMS BELOW SEVERE LIMITS...BUT
PRECIPITABLE WATER VALUES AROUND 2 INCHES WILL RESULT EFFICIENT
RAIN PRODUCING STORMS. THERE WILL BE MODERATE STEERING FLOW SO
FLASH FLOODING IS NOT EXPECTED. THE UPPER TROUGH AXIS WILL MOVE
EAST OF THE REGION OVERNIGHT SATURDAY AND PRECIPITATION CHANCES
WILL END.
BRIEF RIDGING ALOFT IS EXPECTED SUNDAY. HOWEVER...THE RIDGE IS
PROGGED TO FLATTEN SUNDAY NIGHT AS AN UPPER TROUGH DEEPENS AND
MOVES EAST ACROSS THE NORTHERN AND CENTRAL PLAINS. A COLD FRONT
WILL MOVE SOUTHWARD ACROSS THE CENTRAL PLAINS BEHIND THE EASTWARD
MOVING UPPER TROUGH. THE FRONT SHOULD CROSS THE RED RIVER ON
MONDAY AND STALL OVER NORTH TEXAS UNTIL WEDNESDAY. THE ECMWF SOLUTION
AND GFS ARE STARTING TO COME IN LINE WITH EACH OTHER REGARDING THE
STRENGTH OF THE COLD FRONT AND POSITION OF THE ASSOCIATED PRECIP.
HAVE DECIDED TO RAISE POPS IN THE MONDAY THROUGH WEDNESDAY TIME
FRAME...MAINLY BASED ON THE RUN TO RUN CONSISTENCY OF THE ECMWF.
THE BEST RAIN CHANCES SHOULD BE ALONG AND JUST NORTH OF THE COLD
FRONT...ESPECIALLY TUESDAY WHEN A SHORT WAVE ROTATES THROUGH THE
REGION AND PROVIDES ADDITIONAL FORCING. WILL KEEP THE HIGHEST POPS
ACROSS THE NORTHERN HALF OF THE REGION BASED ON THE EXPECTED
POSITION OF THE FRONT. PRECIPITATION CHANCES SHOULD DECREASE FROM
WEST TO EAST TUESDAY NIGHT THROUGH WEDNESDAY AS THE SHORT WAVE
TROUGH MOVES EAST AND THE COLD FRONT BEGINS TO LIFT NORTHWARD IN
RESPONSE TO A DEVELOPING LEE TROUGH.
UPPER LEVEL HIGH PRESSURE WILL BUILD BACK OVER NORTH TEXAS THE END
OF NEXT WEEK THROUGH THE WEEKEND AND RESULT IN WARMER AND RAIN
FREE CONDITIONS.
AFTER ANOTHER HOT DAY TODAY WITH HIGHS IN THE MIDDLE AND UPPER 90S...
TEMPERATURES SHOULD BE A BIT COOLER SATURDAY DUE TO INCREASED
CLOUD COVER AND PRECIPITATION. HOTTER TEMPS WILL BRIEFLY RETURN SUNDAY
DUE TO MORE SUN AND BUILDING HIGH PRESSURE. HOWEVER...SLIGHTLY COOLER
TEMPERATURES ARE ON TAP MONDAY THROUGH WEDNESDAY DUE TO THE
PASSAGE OF THE COLD FRONT AND EXPECTED PRECIP. AFTERNOON HIGHS
MONDAY THROUGH WEDNESDAY WILL RANGE FROM THE UPPER 80S IN THE
NORTH TO THE MID 90S IN THE SOUTH. HIGH TEMPERATURES THE REMAINDER
OF NEXT WEEK WILL BE GENERALLY IN THE MIDDLE 90S. 79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 97 77 94 77 97 / 0 5 30 10 10
WACO, TX 96 75 95 75 95 / 0 5 20 10 10
PARIS, TX 97 74 92 73 93 / 0 5 20 20 10
DENTON, TX 98 74 94 75 96 / 0 5 30 10 10
MCKINNEY, TX 97 75 93 73 94 / 0 5 30 20 10
DALLAS, TX 98 78 95 77 95 / 0 5 20 10 10
TERRELL, TX 97 76 94 74 94 / 0 5 20 10 10
CORSICANA, TX 97 75 93 75 93 / 0 5 20 10 10
TEMPLE, TX 94 73 93 74 93 / 5 5 20 10 10
MINERAL WELLS, TX 96 74 94 72 95 / 5 10 30 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/75
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
133 PM EDT FRI JUN 14 2013
.SYNOPSIS...
COOL HIGH PRESSURE WILL GRADUALLY BUILD INTO THE AREA TONIGHT INTO
FRIDAY BRINGING IN MUCH DRIER AIR INTO THE WEEKEND. MOISTURE WILL
START TO RETURN ON SUNDAY AS THE HIGH MOVES OFFSHORE FOLLOWED BY
A COLD FRONT EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 900 AM EDT FRIDAY...
MADE SOME MINOR ADJUSTMENTS TO CLOUD COVER AND TEMPERATURES
TODAY. NAM AND RAP STILL SHOWED SOME LIGHT SHOWERS WITH THE WEAK
SHORTWAVE THAT DROPS SOUTH ACROSS THE MID ATLANTIC REGION.
MOISTURE REMAINS QUITE SHALLOW BUT LAPSE RATES SUPPORT LIGHT
POP MENTION ACROSS THE NORTH.
AS OF 410 AM EDT FRIDAY...
UPPER TROF MOVES EAST OF THE FORECAST AREA THIS MORNING. A WEAK
SHORT WAVE TRACKS DOWN THE WEST SIDE OF THE TROF AND ACROSS THE
MID ATLANTIC REGION TODAY. TEMPERATURES ALOFT ARE COOL ENOUGH FOR
LARGE LAPSE RATES BUT MOISTURE IS LIMITED. BUFKIT FORECAST
SOUNDINGS SHOWED MOISTURE CONFINED TO SHALLOW LAYER BETWEEN 900
AND 800 MB. MODELS SHOWED BEST POTENTIAL FOR SHOWERS IN THE
WESTERN UPSLOPE AREAS OF SOUTHEAST WEST VIRGINIA AND EAST OF HOT
SPRINGS AND LYNCHBURG THIS AFTERNOON. ANY PRECIPITATION WILL BE
LIGHT.
THE STRATOCUMULUS AND ANY SHOWERS THAT DEVELOP THIS AFTERNOON WILL
DISSIPATE THIS EVENING WITH THE LOSS OF HEATING. 850 MB START OUT
AROUND 35 KNOTS THIS MORNING AND DIMINISH TO LESS THAN 20 KNOTS BY
THIS EVENING. HIGH PRESSURE BUILDS IN TONIGHT AND WILL BE CENTERED
OVER WEST VIRGINIA BY SATURDAY MORNING. SURFACE WINDS WILL
DECOUPLE...AND WITH A CLEAR SKY EXPECT VERY FAVORABLE CONDITIONS
FOR COOLING. SHELTERED VALLEYS IN THE WEST MAY DROP JUST BELOW 50
DEGREES OVERNIGHT.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 326 AM EDT FRIDAY...
SUNDAY WILL PRESENT THE FIRST OPPORTUNITY FOR SHOWERS...MAINLY WEST
OF THE BLUE RIDGE. AN UPPER DISTURBANCE HEADING OUR WAY IS RATHER
SHEARED AND WEAK...ALSO INSTABILITY ISN`T THAT GREAT. THINKING THE
MODELS MAY BE OVERDOING THE AMOUNT OF PRECIP AND COVERAGE SO WENT
A LITTLE LESS THAN GUIDANCE POPS AND DELAYED MOST OF THE RAIN
UNTIL LATE AFTERNOON. COMPARED TO LAST NIGHT`S RUNS...THERE IS A
DEEPER TROUGH OVER THE EASTERN US MONDAY WITH A STRONGER UPPER LOW
OVER SE CANADA...ALSO THE UPPER RIDGE OVER THE SOUTHEASTERN STATES
IS FLATTER. THIS CONFIGURATION WILL SEND A COLD FRONT IN OUR
DIRECTION MONDAY NIGHT AND TUESDAY...WITH MORE SHOWERS AND SOME
STORMS OUT AHEAD OF THE BOUNDARY FOR A CLOUDY YET WARM AND HUMID
MONDAY.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 1215 PM EDT THURSDAY...
HIGH PRESSURE WILL BE OFF THE SOUTHEAST COAST WHILE INCREASING
HUMIDITY AND PIECES OF SHORTWAVE ENERGY MOVE ACROSS THE AREA AHEAD
OF A FRONT. THE PATTERN SUGGESTS THAT MON-TUE WILL HAVE THE BETTER
THREAT OF SHOWERS/STORMS WITH THE FRONT SHIFTING SOUTHEAST OF US BY
WEDNESDAY. HIGH PRESSURE BUILDS IN BEHIND THIS FRONT OVER THE GREAT
LAKES SOUTH INTO THE TN VALLEY WEDNESDAY AND THURSDAY. THE FRONT
WILL STAY HUNG UP ACROSS THE SOUTHEAST SO THERE IS AN OUTSIDE SHOT
THAT SOME OF OUR SRN CWA COUNTIES COULD SEE A FEW SHOWERS WED OR
THU...ALTHOUGH FOR NOW LEFT IT MAINLY DRY. TEMPS ABOVE NORMAL EARLY
BECOME MORE NORMAL POST FRONTAL PASSAGE...WITH HUMIDITY DROPPING
SOME BY WED NIGHT-THU.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 130 PM EDT FRIDAY...
SCATTERED TO BROKEN STRATOCUMULUS AT ROA/BCB/LWB/BLF AND THE
WESTERN UPSLOPE AREAS WILL GRADUALLY DISSIPATE THIS AFTERNOON.
NORTH SURFACE WINDS GUSTING UP TO 20 KNOTS THIS AFTERNOON WILL
DIMINISH THIS EVENING INTO TONIGHT.
HIGH PRESSURE WILL BUILD IN TONIGHT AND SATURDAY RESULTING IN VFR
WEATHER. WITH LIGHT WINDS AND LOW LEVEL MOISTURE ALLOWED
FOR PATCHY FOG AT KLWB OVERNIGHT INTO SATURDAY MORNING.
LOW LEVEL SOUTHERLY FLOW RETURNS ON SUNDAY AHEAD OF ANOTHER FRONT
MOVING INTO THE MIDWEST/GREAT LAKES. MAY SEE FOG AT THE TYPICAL
LOCATIONS SUNDAY MORNING... KLWB/KBCB...OTHERWISE VFR. THE
RETURN OF MOISTURE WILL BRING ISOLATED STORMS TO THE MOUNTAINS
SUNDAY AFTERNOON...WITH BETTER COVERAGE ACROSS THE REGION MONDAY
AND TUESDAY AHEAD/ALONG AND APPROACHING COLD FRONT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...KM/WP
LONG TERM...WP
AVIATION...AMS/KK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
600 PM CDT FRI JUN 14 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 320 PM CDT FRI JUN 14 2013
LATEST WATER VAPOR IMAGERY SHOWED A RIDGE OVER THE THE UPPER
MIDWEST WITH EMBEDDED SHORTWAVES MOVING THROUGH IT. A TROUGH WAS
MOVING INTO EASTERN MONTANA/WYOMING GRADUALLY PUSHING
EAST/NORTHEAST. A SHORTWAVE WAS MOVING ACROSS WESTERN AND CENTRAL
IOWA...FUELING SHOWERS AND THUNDERSTORMS. SURFACE OBSERVATIONS
INDICATED LOW PRESSURE OVER NORTH CENTRAL NEBRASKA SHIFTING EAST.
A WARM FRONT WAS POSITIONED FROM EAST CENTRAL NEBRASKA...EAST
THROUGH SOUTHERN IOWA. A SECOND SURFACE LOW WAS TAKING SHAPE OVER
SOUTHERN SASKATCHEWAN...WITH A SURFACE TROUGH EXTENDING SOUTHWARD
THROUGH CENTRAL NORTH DAKOTA/SOUTH DAKOTA. HIGH PRESSURE WAS
CENTERED OVER LAKE SUPERIOR...MOVING EAST WITH SOUTH/SOUTHEAST WINDS
INCREASING ACROSS THE FORECAST AREA AND USHERING IN A SLIGHTLY
WARMER AND MOIST AIRMASS.
THE SURFACE TROUGH WILL CONTINUE TO ADVANCE EAST THIS EVENING AS THE
WARM FRONT FRONT LIFT INTO NORTHERN IOWA. A SHORTWAVE MOVING THROUGH
THE RIDGE WILL ENTER THE UPPER MISSISSIPPI RIVER VALLEY THIS
EVENING. MEANWHILE...850 MB MOISTURE TRANSPORT RAMPS UP ALONG AND
WEST OF THE INTERSTATE 35 CORRIDOR EARLY THIS EVENING THEN QUICKLY
FOCUSES EAST INTO THE FORECAST AREA. PERIODS OF SHOWERS AND
THUNDERSTORMS ARE EXPECTED OVER THE AREA THIS EVENING INTO THE
OVERNIGHT HOURS. THE FOCUS FOR THE HEAVIEST RAINFALL WILL BE OVER
NORTHERN IOWA INTO FAR SOUTHWEST WISCONSIN...WHERE THE STRONGEST 850
MB MOISTURE TRANSPORT FOCUSES INTO THE FRONT. PRECIPITABLE WATER
VALUES CLIMB INTO THE 1.5 TO 1.9 RANGE ACROSS MUCH OF THE FORECAST
AREA THIS EVENING AND HOVER THERE THROUGH MUCH OF THE OVERNIGHT.
ALSO...WARM CLOUD DEPTH INCREASES TO AROUND 4KM ACROSS MUCH OF THE
REGION. THE THUNDERSTORMS SHOULD BE EFFICIENT RAIN PRODUCERS...WITH
LOCALLY HEAVY RAINFALL POSSIBLE. THE SURFACE TROUGH SLIDES THROUGH
LATE TONIGHT FOR LOCATIONS NORTH OF INTERSTATE 90...BUT THE WARM
FRONT LINGERS OVER NORTHERN IOWA INTO FAR SOUTHWEST WISCONSIN AND
THE MOISTURE TRANSPORT CONTINUES TO FOCUS INTO IT. THIS SHOULD LEAD
TO REPEATED ROUNDS OF SHOWERS AND STORMS OVER THESE AREAS...LEADING
TO POTENTIAL FLASH FLOODING. AREAS THAT HAVE RECEIVED RECENT HEAVY
RAINFALL ARE AT GREATEST RISK OF SEEING FLASH FLOODING. CANNOT RULE
OUT AN ISOLATED SEVERE HAIL REPORT OR TWO GIVEN ELEVATED CAPE VALUES
APPROACHING 2000 J/KG VERY LATE TONIGHT INTO SATURDAY MORNING.
HOWEVER...SHEAR IS LIMITED AND WITH VERY HIGH FREEZING LEVELS IT
WILL TAKE UPDRAFT ROTATION TO GROW LARGE ENOUGH HAILSTONES TO
OVERCOME THE HIGHER FREEZING LEVELS. SHOWERS AND STORMS WILL BE
ONGOING EARLY SATURDAY MORNING...ESPECIALLY ALONG AND SOUTH OF
INTERSTATE 90. WEAK RIDGING MOVES IN IN WAKE OF THE FIRST ROUND OF
SHOWERS/STORMS MID MORNING ON SATURDAY THEN ANOTHER SHORTWAVE
MOVES IN LATE SATURDAY MORNING INTO EARLY SATURDAY AFTERNOON.
ANOTHER ROUND OF SHOWERS AND STORMS EXPECTED WITH THIS WAVE. AGAIN
THE STORMS WILL BE CAPABLE OF PRODUCING HEAVY RAINFALL. THE
SURFACE TROUGH LOOKS TO BE POSITIONED ALONG THE INTERSTATE 35
CORRIDOR AROUND 15Z SATURDAY MORNING...THEN PUSHES EAST THROUGH
THE FORECAST AREA DURING THE LATE MORNING AND AFTERNOON HOURS.
DEPENDING ON WHETHER OR NOT WE SEE SOME SUNSHINE/DESTABILIZATION
IN THE WAKE OF THE FIRST ROUND OF ACTIVITY. THERE IS THE
POSSIBILITY OF SEEING A FEW STRONG TO SEVERE STORMS DEVELOPING
ALONG THIS SURFACE TROUGH. 0-6KM BULK SHEAR INCREASES IN THE
AFTERNOON HOURS TO AROUND 30 KTS AS THE SHORTWAVE MOVES IN.
ALSO...FORECAST SOUNDINGS SUGGEST WE COULD SEE SURFACE BASED CAPE
VALUES CLIMB TO AROUND 2000 J/KG. THE SHEAR LOOKS TO LAG BEHIND
THE WAVE SO THIS WOULD BE A LIMITING FACTOR FOR SEVERE POTENTIAL.
THE HIGHEST CHANCES FOR SHOWERS AND STORMS SATURDAY AFTERNOON WILL
OVER NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN. THE STRONGEST
MOISTURE TRANSPORT FOCUSES INTO SOUTHERN AND EASTERN IOWA BY
SATURDAY AFTERNOON. ALSO...THE OVERNIGHT MCS ACTIVITY COULD HELP
PUSH THE WARM FRONT TO THE SOUTH. WILL HAVE TO KEEP A VERY CLOSE
EYE ON THE POSITION OF THE WARM FRONT ON SATURDAY. PLAN ON HIGH
TEMPERATURES ON SATURDAY IN THE MID TO UPPER 70S.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 PM CDT FRI JUN 14 2013
THE SURFACE TROUGH PUSHES EAST OF THE FORECAST AREA SATURDAY
EVENING. ANOTHER ROUND OF CONVECTION ALONG THE WARM FRONT LATE
SATURDAY AFTERNOON INTO SATURDAY EVENING OVER NORTHEAST IOWA AND FAR
SOUTHWEST WISCONSIN WILL HELP TO PUSH THE WARM FRONT BACK TO THE
SOUTH...CLOSER TO THE INTERSTATE 80 CORRIDOR. SHOWERS AND STORMS
SHOULD TAPER OFF AND DURING THE EVENING HOURS AND FOCUS
SOUTH/SOUTHEAST OF THE FORECAST AREA. WEAK HIGH PRESSURE THEN MOVES
INTO THE REGION WITH THE FORECAST AREA BETWEEN SYSTEMS SATURDAY LATE
NIGHT INTO SUNDAY. SUNDAY IS SHAPING UP TO BE A RATHER PLEASANT LATE
SPRING DAY. UNDER PARTLY SUNNY SKIES...PLAN ON HIGHS CLIMBING INTO
THE LOWER TO MID 80S. AN UPPER TROUGH THEN RACES SOUTHEAST SUNDAY
NIGHT OUT OF SOUTHERN MANITOBA/ONTARIO AND HEADS TOWARD THE FORECAST
AREA. THERE ARE SOME SLIGHT TIMING DIFFERENCES IN THE FORECAST
MODELS ON EXACTLY WHEN THE TROUGH WILL PASS THROUGH. CURRENT
THINKING IS THAT THE TROUGH SHOULD MOVE THROUGH LATE SUNDAY SUNDAY
NIGHT INTO MONDAY MORNING...BRINGING CHANCES FOR SHOWERS AND
THUNDERSTORMS TO THE AREA. THE TROUGH FINALLY EXITS THE REGION LATE
MONDAY AFTERNOON WITH HIGH PRESSURE BUILDING ACROSS THE REGION IN
ITS WAKE. QUIET NORTHWEST FLOW ALOFT AND SURFACE HIGH PRESSURE IN
PLACE WILL PROVIDE DRY AND QUIET WEATHER THROUGH AT LEAST WEDNESDAY.
FORECAST MODELS ARE SUGGESTING SOME WEAK IMPULSES WILL MOVE THROUGH
THE AREA LATE IN THE WEEK BRINGING SOME LOW CHANCES FOR SHOWERS AND
STORMS TO THE AREA. HOWEVER MODEL SOLUTIONS START TO DIVERGE BEYOND
THURSDAY SO HAVE LEANED TOWARD MODEL CONSENSUS BLEND. HIGH
TEMPERATURES ARE EXPECTED TO RANGE FROM THE 70S TO AROUND 80S
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 600 PM CDT FRI JUN 14 2013
CURRENT SHRA/TS OVER CENTRAL IA SHOULD CONTINUE TO MARCH
SOUTHEAST...PER RAP CORFIDI VECTORS. BROAD SWATH OF LOW LEVEL
SOUTH-NORTH RUNNING LOW LEVEL MOISTURE TRANSPORT WILL GRADUALLY
SHIFT EAST TONIGHT...TRANSITIONING ACROSS THE AREA. MEANWHILE...A
RIDGE OF INSTABILTY ALSO SHIFTS EAST...DIMINISHING SOMEWHAT WITH THE
LOSS OF DAYTIME HEATING. THIS UNSTABLE...MOIST AIR WILL SERVE AS THE
FUEL FOR SHRA/TS DEVELOPMENT. THE QUESTION...AND WHERE THE
UNCERTAINLY LIES...IS WHAT WILL SERVE AS THE KICKERS FOR PCPN.
LATEST WATERVAPOR IMAGERY HINTS AT BITS OF UPPER LEVEL ENERGY THAT
COULD SPIN ACROSS THE REGION TONIGHT. AT THE SFC...A WARM FRONT IS
EXPECTED TO LIFT INTO CENTRAL IA OVERNIGHT. BELIEVE IA IS THE MOST
LIKELY TO EXPERIENCE THE MOST WIDESPREAD SHRA/TS TONIGHT...VIA
LATEST HRRR. HOWEVER...NAM12 TRACKS A BATCH OF RAIN DIRECTLY ACROSS
KRST/KLSE THIS EVENING...WHILE THE ARXLAPS DEVELOPS AN APPRECIABLE
AMOUNT OF RAIN WITHIN THE MOISTURE TRANSPORT BETWEEN 03-06Z...AGAIN
OVER THE TAF SITES.
CONFIDENCE IS LOW IN JUST HOW ALL WILL EVOLVE. WILL TREND TOWARD
THE HRRR FOR NOW...BUT ANTICIPATE UPDATES WILL BE NEEDED AS
SATELLITE/RADAR TRENDS BECOME MORE APPARENT.
&&
.HYDROLOGY...THIS EVENING THROUGH SATURDAY EVENING
ISSUED AT 320 PM CDT FRI JUN 14 2013
HEAVY RAINFALL COULD LEAD TO FLASH FLOODING OVER PORTIONS OF
SOUTHEAST MINNESOTA INTO NORTHEAST IOWA THIS EVENING THROUGH
SATURDAY EVENING. THE AREAS OF GREATEST CONCERN ARE LOCATIONS THAT
RECEIVED HEAVY RAINFALL ON WEDNESDAY...SUCH AS PORTIONS OF DODGE
AND FILMORE COUNTIES IN SOUTHEAST MINNESOTA...AND MUCH OF
NORTHEAST IOWA ESPECIALLY FLOYD AND MITCHELL COUNTIES. 1 TO 2
INCHES OF RAINFALL ARE POSSIBLE BY SATURDAY EVENING. LOCALLY
HIGHER AMOUNTS ARE NOT OUT OF THE QUESTION UNDER ANY STRONGER
THUNDERSTORMS.
A LINE OF SHOWERS AND STORMS WILL TRACK ACROSS PORTIONS OF
NORTHEAST IOWA LATE THIS AFTERNOON INTO EARLY THIS EVENING.
SHOWERS AND THUNDERSTORMS WILL BECOME WIDESPREAD LATE THIS
EVENING INTO THE OVERNIGHT HOURS AS A WARM FRONT LIFTS INTO
NORTHERN IOWA AND MOISTURE TRANSPORT FOCUSES INTO THE FRONT.
ANOTHER ROUND OF SHOWERS AND STORMS ARE EXPECTED LATE SATURDAY
MORNING INTO SATURDAY AFTERNOON. THE THUNDERSTORMS TONIGHT THROUGH
SATURDAY WILL BE VERY EFFICIENT RAIN PRODUCERS WITH PRECIPITABLE
WATER VALUES OF 1.5 TO 1.9 INCHES AND WARM CLOUD DEPTHS HOVERING
AROUND 4000 METERS. WILL CONTINUE THE FLASH FLOOD WATCH THROUGH
SATURDAY EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...FLASH FLOOD WATCH THROUGH SATURDAY EVENING FOR MNZ094-095.
IA...FLASH FLOOD WATCH THROUGH SATURDAY EVENING FOR IAZ008>010-018-
019-029-030.
&&
$$
SHORT TERM....WETENKAMP
LONG TERM.....WETENKAMP
AVIATION......RIECK
HYDROLOGY.....WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
105 PM CDT FRI JUN 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CDT FRI JUN 14 2013
MAIN FORECAST FOCUS IS ON POTENTIAL FOR HEAVY RAIN/FLASH FLOODING
LATER TODAY THROUGH SATURDAY.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A HIGHLY AMPLIFIED PATTERN ACROSS NORTH AMERICA...CONSISTING
OF TROUGHING OVER ALBERTA AND IDAHO...RIDGING FROM THE SOUTHERN
PLAINS INTO MANITOBA...AND TROUGHING FROM SOUTHEAST CANADA SOUTHWARD
ALONG THE EAST COAST OF THE U.S.. THE FORECAST AREA LIES ON THE
SUBSIDENT SIDE OF THE RIDGING...RESULTING IN HIGH PRESSURE AT THE
SURFACE WHICH EXISTS OVER WISCONSIN. 00Z SOUNDINGS FROM MPX...GRB
AND DVN DEPICTED A DRY AIRMASS WITH THIS HIGH PRESSURE AREA WITH
PRECIPITABLE WATER VALUES OF 0.7-0.8 INCHES OR 80-90 PERCENT OF
NORMAL. THE DRY AIRMASS HAS HELPED KEEP SKIES MOSTLY CLEAR OVERNIGHT
AND WITH LIGHT WINDS...TEMPERATURES HAVE DROPPED INTO THE UPPER 40S
TO UPPER 50S. MEANWHILE...TO THE WEST UNDER AND WEST OF THE UPPER
RIDGE AXIS...MOISTURE HAS BEEN GRADUALLY ADVECTING NORTHWARD THROUGH
THE PLAINS ON A 30-45 KT 850MB JET PER VWP DATA. GOES DERIVED
PRECIPITABLE WATER SHOWED VALUES OF 1-1.5 INCHES ACROSS MUCH OF THE
PLAINS...HIGHEST ACROSS SOUTH CENTRAL NEBRASKA AND NORTH CENTRAL KS.
THIS MAXIMA WAS ALSO CORRELATED WITH THE REMNANTS OF AN MCS THAT
INITIATED OFF THE FRONT RANGE IN COLORADO YESTERDAY AFTERNOON. ALONG
WITH THE INCREASED MOISTURE...00Z RAOBS SHOWED 850MB TEMPS OF 16-21C
FROM RAPID CITY TO OMAHA AND TOPEKA...QUITE A BIT WARMER COMPARED TO
THE 10-13C AROUND THE FORECAST AREA. ALONG THE GRADIENT OF THIS
TEMPERATURE DIFFERENCE...A NARROW LINE OF SHOWERS AND THUNDERSTORMS
HAS BROKE OUT OVER SOUTHWEST MN INTO WESTERN IA.
OVER THE NEXT 24 HOURS...THE UPPER RIDGE AXIS OVER THE PLAINS IS
PROGGED TO SHIFT EAST OVER THE FORECAST AREA. THIS IS IN RESPONSE TO
THE TROUGH OVER IDAHO AND ALBERTA EJECTING NORTHEAST...AS WELL AS
FORMING A DEEP CLOSED LOW CIRCULATION OVER CENTRAL SASKATCHEWAN.
WHAT THIS MEANS FOR THE FORECAST AREA IS ALL OF THAT WARMER 850MB
AIR AND HIGHER PRECIPITABLE WATER UNDER THE UPPER RIDGE WILL MOVE
TOWARDS US. GIVEN THE WARM ADVECTION PATTERN...EXPECT CONCERN FOR
PRECIPITATION TO INCREASE. IN ADDITION...CONVECTIVELY INDUCED
SHORTWAVES FROM CONVECTION COMING OFF THE ROCKIES AND THE PLAINS
THIS MORNING...AND THOSE THAT FIRE THIS AFTERNOON...WILL ALSO PLAY A
ROLE AS THEY HEAD NORTHEAST AROUND THE UPPER RIDGE.
FOR TODAY...GENERAL CONSENSUS FROM THE MODELS IS FOR INCREASING
310-315K ISENTROPIC LIFT AND 700MB MOISTURE TRANSPORT TO COME ACROSS
THE FORECAST AREA DURING THE AFTERNOON. ANTICIPATING AN
ALTOSTRATUS/ACCAS DECK TO FORM AS A RESULT AND OVERSPREAD MUCH OF
THE AREA. THIS CAN ALREADY BE SEEN ALONG THE DAKOTAS/MN BORDER WHERE
THOSE SHOWERS AND THUNDERSTORMS HAVE BEEN OCCURRING. HAVE
CONTINUED THE MENTION OF SOME LOW PROBABILITIES FOR PRECIPITATION
WEST OF THE MS RIVER EARLY THIS AFTERNOON TO ACCOUNT FOR THIS SHOWER
POTENTIAL.
LATE IN THE AFTERNOON...SOMETHING TO WATCH IS THE 14.00Z NAM
SCENARIO WHICH DEPICTS A LARGER AMOUNT OF CONVECTION OVER SOUTH
CENTRAL MN AND NORTH CENTRAL IA...CLIPPING FAR WESTERN PORTIONS OF
THE FORECAST AREA. THE GFS/ECMWF/REGIONAL CANADIAN ARE VERY
SIMILAR...THOUGH QPF VALUES ARE NOT NEARLY AS HIGH WHICH MAY BE A
RESULT OF MODEL RESOLUTION. THE SITUATION APPEARS TO BE A RESULT OF
INCREASING 700-850MB MOISTURE TRANSPORT...ON THE LEADING EDGE OF THE
HIGHER PRECIPITABLE WATER VALUES OF 1.5-1.8 INCHES PER RAP COMING
INTO WESTERN IA...CAPE OF 1000 J/KG OR SO THAT IS UNCAPPED LIFTED
FROM 725MB...AND A POSSIBLE RIGHT ENTRANCE REGION OF A JET STREAK
TRACKING SOUTHEAST THROUGH WISCONSIN. SHOULD THIS PAN OUT...GIVEN
THE HIGH PRECIPITABLE WATER...THESE STORMS WILL BE HEAVY RAIN
PRODUCERS.
NAM/GFS/ECMWF/REGIONAL CANADIAN MOISTURE TRANSPORT FIELDS FROM
925-700MB ARE ALL IN AGREEMENT THAT THE STREAM SHIFTS NORTHEAST
TONIGHT...FOLLOWING THE UPPER RIDGE AXIS. THUS...THINKING THE
CONVECTION THAT FIRES LATE THIS AFTERNOON SHOULD SLOWLY PROGRESS
EASTWARD THROUGH THE FORECAST AREA. ADDITIONALLY...IT APPEARS THERE
IS A SECOND SURGE OF MOISTURE TRANSPORT COMING UP OUT OF KS INTO
CENTRAL IA OVERNIGHT...LIKELY FIRING MORE CONVECTION ON ITS NOSE
FROM NORTH CENTRAL INTO EASTERN IA. THE ECMWF HAS BEEN EXTREMELY
CONSISTENT RUN TO RUN WITH THIS.
ALTHOUGH INSTABILITY IS ADVECTING TOWARDS US ON THIS MOISTURE
TRANSPORT...THE INSTABILITY IS TALL AND SKINNY. WITH WARM CLOUD
DEPTHS APPROACHING 14 KFT...THINKING HEAVY RAIN WOULD BE THE MAIN
SEVERE WEATHER CONCERN. ADDITIONALLY...THE 2-7KM SHEAR WHICH IS MORE
REPRESENTATIVE OF THE INSTABILITY USED BY THE STORMS...IS LESS THAN
30 KTS. SEE THE HYDROLOGY SECTION BELOW FOR MORE ON THE IMPACTS FROM
THE PRECIPITATION. MAIN THING TO NOTE HERE IS THAT GIVEN THE MOIST
SOILS OVER PORTIONS OF NORTHEAST IA AND SOUTHEAST MN...ANY HEAVY
RAIN MAY CAUSE FLASH FLOODING...ESPECIALLY IN FLOYD AND MITCHELL
COUNTIES IN IA. THEREFORE...HAVE ISSUED FLASH FLOOD WATCHES FOR THE
MOST CONCERNING AREAS.
850MB TEMPERATURES ARE PROGGED TO STAY BETWEEN 10-13C TODAY. WITH
INCREASING CLOUDS...TEMPERATURES SHOULD END UP NEAR OR A LITTLE
BELOW YESTERDAY HIGHS. WARMER NIGHT ON TAP AS HIGHER DEWPOINTS MOVE
IN ACCOMPANYING THE HIGHER PRECIPITABLE WATER.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 329 AM CDT FRI JUN 14 2013
SATURDAY THROUGH MONDAY...
MODELS ARE IN GOOD AGREEMENT FLATTENING THE UPPER RIDGE OVER THE
AREA ON SATURDAY...AGAIN RESULTING FROM THE EJECTING IDAHO TROUGH.
EVENTUALLY...THE CLOSED UPPER LOW THAT FORMED OVER SASKATCHEWAN ON
SATURDAY WILL APPROACH THE AREA...PROGGED TO DROP INTO CENTRAL MN AT
12Z MONDAY AS A SHORTWAVE TROUGH. THIS TROUGH MAY EVEN BEGIN TO
PHASE WITH THE GENERAL TROUGHING OVER SOUTHEAST CANADA AS INDICATED
BY THE 00Z ECMWF.
WITH THE FLOW TURNING ZONAL ON SATURDAY...THE MAIN MOISTURE
TRANSPORT STREAM SUPPORTING CONVECTION TONIGHT SHOULD PUSH OFF TO
THE EAST. THUS...LIKE CLIMATOLOGY FOR NOCTURNAL CONVECTION...
EXPECTING IT TO WEAKEN THROUGH THE MORNING HOURS. HOWEVER...OUTFLOW
BOUNDARIES FROM THE CONVECTION AND WHAT SHOULD BE A COLD FRONT AT
THE SURFACE ARE SUGGESTED TO LAY UP OVER SOUTHERN SECTIONS OVER THE
FORECAST AREA. GROWING INSTABILITY FROM ANY DAYTIME HEATING PLUS A
HUMID AIRMASS CHARACTERIZED BY DEWPOINTS IN THE MID-UPPER
60S...ALONG WITH PRECIPITABLE WATER VALUES OF 1.5-1.8 INCHES...
SHOULD PROMOTE RENEWED CONVECTION. AGAIN...HEAVY RAIN WOULD BE THE
MAIN CONCERN AND THUS THE FLASH FLOOD WATCH GOES THROUGH THE DAY
SATURDAY. OUTFLOWS FROM THIS NEW CONVECTION COMBINED WITH THE COLD
FRONT DROPPING SOUTHEAST SHOULD PUSH MUCH OF THE CONVECTION OUT OF
THE AREA SOMETIME DURING THE EVENING. EXACT TIMING STILL HARD TO PIN
DOWN. LEFT SOME LOW CHANCES IN AFTER MIDNIGHT INTO THE DAY SUNDAY
ACROSS FAR SOUTHERN SECTIONS OF THE AREA WITH THE 14.00Z GFS/ECMWF
SHOWING SOME LIGHT QPF LINGERING. HOWEVER...BELIEVE THESE MIGHT BE
ABLE TO BE REMOVED IN LATER FORECASTS WITH A WEAK RIDGE OF HIGH
PRESSURE IN PLACE. ATTENTION SUNDAY NIGHT AND MONDAY TURNS TO THE
TROUGHING DROPPING INTO MINNESOTA. DPVA AHEAD OF THE TROUGH PLUS A
SURGE OF 850-700MB MOISTURE TRANSPORT MAY BE ENOUGH TO KICK OFF SOME
SHOWER AND THUNDERSTORM ACTIVITY. HOWEVER...THE TROUGH IS COMING
THROUGH AT THE WRONG TIME OF DAY TO GET EXCITED ABOUT IT...AND
MOISTURE IS LACKING WITH PRECIPITABLE WATER VALUES MAYBE AROUND 1
INCH. THEREFORE...HAVE ONLY WENT WITH 20-40 PERCENT CHANCES ACROSS
THE FORECAST AREA. 13.12Z/14.00Z ECMWF EVEN SUGGESTS THE TROUGH AND
ITS ASSOCIATED COLD FRONT COULD COME THROUGH THE AREA MAINLY DRY.
WITH WARMER 850MB TEMPS ON SATURDAY...14-17C...AND MORE SUNSHINE ON
SUNDAY WITH SIMILAR READINGS...EXPECT TEMPERATURES TO RISE EACH DAY.
MOST LOCATIONS SHOULD SEE GOOD MIXING ON SUNDAY...BOOSTING HIGHS
INTO THE LOW TO MID 80S. COOLER READINGS ON TAP FOR MONDAY WITH THE
COLD FRONT COMING THROUGH. GENERALLY FOLLOWED A BLEND OF GUIDANCE
FOR HIGHS AND LOWS.
MONDAY NIGHT THROUGH THURSDAY...
VERY GOOD MODEL AGREEMENT EXISTS AMONGST THE 14.00Z
ECMWF/GFS/CANADIAN AND GFS ENSEMBLES ON THE UPPER LEVEL PATTERN.
MUCH OF THE PERIOD IS DOMINATED BY TROUGHING ALONG THE U.S. WEST
COAST...RIDGING FROM THE NORTHWEST TERRITORIES OF CANADA INTO THE
CENTRAL PLAINS...AND TROUGHING OVER EASTERN CANADA INTO THE GREAT
LAKES. THIS MEANS MOSTLY A NORTHWEST FLOW OF COOL AND DRY AIR FROM
CANADA. THUS...MUCH OF THE FORECAST IS DRY. THERE ARE INDICATIONS OF
A SHORTWAVE DROPPING THROUGH THE WESTERN GREAT LAKES ON
THURSDAY...BRINGING A COLD FRONT INTO THE AREA. HAVE INCLUDED 20
PERCENT CHANCES FOR SHOWERS AND THUNDERSTORMS NORTH OF I-90 FOR THIS
FEATURE. TEMPERATURE WISE...THE COOLEST DAY LOOKS TO BE TUESDAY WITH
HIGH PRESSURE OVERHEAD AND 850MB TEMPS OF 8-10C. AIRMASS
MODIFICATION THANKS TO THE STRONG JUNE SUN SHOULD HELP WARM
TEMPERATURES EACH DAY THEREAFTER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 105 PM CDT FRI JUN 14 2013
SHORT WAVE ENERGY ALONG NORTHERN TIER OF STATES CONTINUES TO FIRE
THREAT FOR CONVECTION...EVEN WITH SHORT TERM RIDGE IN PLACE. TIMING
AND EXTENT OF THIS THREAT IS MAIN CHALLENGE FOR AVIATION WITH GOOD
VFR CONDITIONS IN PLACE RIGHT NOW.
EXPECT INITIAL DEVELOPMENT LATER TODAY TO THE WEST BUT UNCERTAINTY
IN WHERE AND EXACTLY WHEN. BANKING ON HIGHER CHANCES FOR STORMS TO
ROLL IN OVERNIGHT AND THEN PASS THROUGH TOWARDS DAYBREAK SATURDAY
WITH GENERAL RETURN TO VFR AFTER THAT. HARD TO GIVE EXACT TIMING OF
STORMS BUT WILL TRY AND NAIL DOWN 3-4 HOUR WINDOW WITH HIGHEST
CHANCES.
&&
.HYDROLOGY...LATE THIS AFTERNOON THROUGH SATURDAY
ISSUED AT 329 AM CDT FRI JUN 14 2013
VERY WET SOILS ACROSS MOWER AND FILLMORE COUNTIES IN MN ALONG WITH
MUCH OF NORTHEAST IOWA OVER THE PAST WEEK...AND REALLY THE PAST
COUPLE MONTHS...RESULT IN A HUGE CONCERN FOR FLOODING. THAT 1-2
INCHES OF RAINFALL THAT IMPACTED FLOYD COUNTY IA LATE WEDNESDAY...
MOSTLY IN A SHORT TIME PERIOD...CAUSED A LOT OF FLOODING ISSUES.
EXPECTING A BAND OF THUNDERSTORMS TO MOVE INTO MOWER THROUGH FLOYD
COUNTIES LATE THIS AFTERNOON...SLOWLY MOVING EAST THROUGH THE
EVENING. ADDITIONAL THUNDERSTORMS ARE FORECAST AFTER MIDNIGHT AND
THROUGH MUCH OF THE DAY SATURDAY SOUTH OF I-90. WITH PRECIPITABLE
WATER VALUES OF 1.5-1.8 INCHES AND WARM CLOUD DEPTHS OF 3500-4200
METERS ACCOMPANYING THESE THUNDERSTORMS...HEAVY RAIN IS LIKELY. WE
COULD BE LOOKING AT A WIDESPREAD 1-2 INCHES OF RAINFALL SOUTH OF
I-90...HIGHEST ACROSS NORTHEAST IOWA. LOCALLY HEAVIER RAINFALL IS
EASILY POSSIBLE.
GIVEN THE VERY WET SOILS AND POTENTIAL FOR HEAVY RAIN...HAVE ISSUED
A FLASH FLOOD WATCH FOR MOWER AND FILLMORE COUNTIES IN MN AND MUCH
OF NORTHEAST IA EXCEPT ALLAMAKEE. DEPENDING ON HOW CONVECTION
EVOLVES...THE WATCH MAY NEED TO BE EXPANDED EASTWARD...MOST LIKELY
INTO FAR SOUTHWEST WI.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...FLASH FLOOD WATCH FROM THIS AFTERNOON THROUGH SATURDAY EVENING
FOR MNZ094-095.
IA...FLASH FLOOD WATCH FROM THIS AFTERNOON THROUGH SATURDAY EVENING
FOR IAZ008>010-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....SHEA
HYDROLOGY....AJ