Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/28/16
Area Forecast Discussion
National Weather Service Bismarck ND
941 PM CDT Tue Sep 27 2016
.UPDATE...
Issued at 929 PM CDT Tue Sep 27 2016
Decided to hold off on the frost advisory for eastern portions of
central ND. Low dewpoint air (mid 30s) over the far eastern CWA
counties gets pushed westward toward the Highway 83 corridor and
settles around 37 to 39 degrees over eastern portions of the CWA.
In addition, there are still indications from meso-scale models
that there could be some fog developing over this area as higher
dewpoint air to the east settles in with clear skies and light
winds. Whether we get some fog or not...it looks like temperaturesshould
remain mainly in the mid 30s, and then only for an hour or two
before temperatures begin to rise with daybreak. Because it`s such
a shallow layer of moisture that moves into the area, not
convinced about the fog either. Will hold off right now on mention
of fog and will still mention patchy frost over eastern portions
of the CWA.
Otherwise no significant changes to the going forecast. Updated
latest sensible weather elements and blended to late evening
temperatures. Updated text products out shortly.
UPDATE Issued at 626 PM CDT Tue Sep 27 2016
Only a few tweaks to the forecast at this time. Main concern this
evening will be possible frost potential over our eastern
counties. Latest satellite loops show clouds associated with the
upper low over the northern Great Lakes along the eastern ND
border. but from wv loop mid level moisture extends to our easter
CWA border, with a well defined dry slot over the James River
Valley into the Devils Lake Basin. You can see this also with
lowest dewpoints in the upper 20s within this region and higher
dewpoints in the 40s just to the east and west.
Latest runs of the mesoscale models including the HRRR indicate
moisture pushing west into our eastern CWA counties overnight in
response to a wave dropping down the back side of the upper low.
This is resulting in the development of low level moisture in the
form of stratus/fog over eastern portions of central ND after 06
UTC. This is also noted to some extent in the global GFS and NAM.
However, at this time the western extent of cloud cover is not as
far west as models depict.
If the low level moisture does not develop as depicted by models
we may still need to issue a frost advisory over eastern portions
of central ND, although the length of time in frost advisory
criteria may be limited. If we do see the low stratus/fog
develop, it would likely keep temperatures from reaching advisory
criteria. Will continue to monitor this evening and if needed will
get an advisory out before the 10 PM News.
Otherwise a quiet evening with clear skies across the forecast
area.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 337 PM CDT Tue Sep 27 2016
Latest water vapor imagery loop shows an upper level high
circulation over northern Utah with ridging extending northeast
through Montana and into southern Saskatchewan and western
Manitoba. Models continue to show heights building with the ridge
amplifying across western and central ND tonight through
Wednesday. This is in response to a closed low sagging south from
the Great Lakes into the Ohio Valley. The end result will be sunny
and warmer weather conditions Wednesday with highs ranging from 63
in the Turtle Mountains to 74 in the southwest.
Will not mention any frost tonight as the coolest air will be focused
into eastern ND, and just graze our eastern counties, from the
Turtle Mountains south into the James River Valley. Only expect an
hour or possibly two hours where temperatures will drop to around
37 degrees, which is on the upper bound of the frost advisory
criteria. Based on this, will not issue and highlights at this time.
The evening shift can re-evaluate this again for possible changes.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 337 PM CDT Tue Sep 27 2016
Water vapor today also shows an upper low circulating across
southern Arizona. This low is currently cutoff from the main
westerlies to the north, but as a deepening upper trough sinks
south from the Gulf Of Alaska, the cutoff low get picked up is
pushed northeast on the western side of the upper ridge mentioned
in the short term period. Dry weather will prevail Wednesday night
through Thursday evening, with chances of showers and possible
thunderstorms creeping into the west Thursday night, as a 40kt 850mb
flow southerly jet becomes established. Most unstable cape and
0-6km shear values on both the GFS and ECMWF will yield at least a
slight chance of thunderstorm mention Thursday night across the
west. The upper wave shifts across central ND Friday but weakens
at the same time. Ridging briefly returns again Saturday for a dry
day before the aforementioned west coast trough sends successive
shortwave troughs through western and central ND Sunday into
Monday, with another shortwave possibly by midweek; however by the
Tuesday/Wednesday timeframe the GFS and ECMWF depart on overall
timing and placement of the shortwaves.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 929 PM CDT Tue Sep 27 2016
High pressure with light surface winds will remain over the
forecast area through the 00Z TAF period. There are some
indications of possible fog/stratus over eastern portions of
central ND, possibly as far west as KMOT and KBIS. Not confident
enough to jump on this completely given the amount of dry air
currently over the area, with only a very shallow layer of
moisture developing. Did bring a mention of scattered IFR clouds
at KJMS aft 06 UTC. KBIS and KMOT are currently depicted to be
just west of the far western edge of fog/stratus so did not
include them at this time. No issues at KDIK and KISN through the
period.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...KS
LONG TERM...KS
AVIATION...TWH
Area Forecast Discussion
National Weather Service Cleveland OH
928 PM EDT TUE SEP 27 2016
.SYNOPSIS...
An area of low pressure will move from the Upper Lakes overnight
into the Ohio Valley by Wednesday. This feature will meander over
the region for several days providing cloudy skies, rain, and
isolated thunderstorms.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
Have gone ahead and made some changes to the forecast based on the
new guidance coming latest. HRRR is showing precip blossoming over
the western end of the area toward morning. Have gone ahead an
bumped pops up for late tonight in the west. Have also sped up the
precip and increased chances on Wednesday. With the upper low
rotating over the area there will be precip a plenty. No changes
to temps. Have adjusted cloud conditions in hopes of capturing
current trends.
Previous...The dry slot over the region will push east overnight.
Energy moving in advance of an upper low dropping south from the
Lake Superior this evening will help develop some clouds over the
area. The clouds will progressively fill in overnight as a strong
vort max moves in. This feature along with height drops will begin
to support shower activity mainly in our western counties. Believe
the showers should hold off until daybreak given how much dry air
needs to be overcome to support measurable rain. Winds will come
down overnight as the mixing is reduced. Temperatures will drop
down into the lower 50s. Some area will touch the upper 40s, but
given more wind and encroaching clouds than last night most areas
should remain in the 50s.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As stated above the rain chances will start Wednesday morning
mainly in the west and gradually spread east through late morning.
The height falls associated with the upper low are impressive,
which will help steepen the lapse rate over the area. Temperatures
will struggle to reach the upper 60s given cloud cover and
showers, but this will be sufficient to support thunder. Best
timing will be early afternoon when the vort max moves in.
The upper low will become cut off right over the Ohio Valley
through late week. Generally speaking conditions under this set up
are cloudy skies with on and off showers with isolated
thunderstorms during peak heating (or timing of best divergence
aloft and/or convergence along the moisture axis). The exact
placement and evolution of this feature and the surface low could
have big impacts on the rainfall forecast. The location of the mid
level moisture advection from the Atlantic combined with the
placement of the left exit region of the upper level jet,
deformation zone, and vorticity max will help develop large bands
of rain that could extend into southern PA. On the flip side a dry
slot could move in and bring a break to the rain for portions of
the CWA. The favored location at this time looking at the
impressive forcing aloft is the north and eastern counties
Thursday into Friday. These areas could see hours of moderate to
heavy rainfall. Overall most areas should see an inch of rain
through the end of the week with the potential for notably more.
The slow movement of the low could lead to excessive rainfall
problems should banding develop over the area. Will have to see
how the models come in-line over the next 24hrs.
Temperatures will be challenging as well. There will be warm
advection moving in Thursday and Friday as we develop a strong
moisture feed from the mid Atlantic. However the upper level low
will support notably cooler temperatures. Believe we could see a
bigger temperature gradient from West to East as the exact
placement of the low and surface features come into line. For now
have temperatures generally in the 60s.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Fall is upon us and the overall pattern is shaping up to remind us
this season is here. Vertically stacked low right on top of the
local forecast area will slowly meander around the eastern Great
Lakes through the forecast period. The upper level low sort of gets
cut off and begins the slow shift east as amplification of the broad
upper level ridge encompassing three fourths of the United States
and Canada begins to shift east. The stacked low will keep a
relatively cool pool of air over the forecast area along with
pumping a conveyor belt of moisture in from the Atlantic Ocean. This
flow of moist air could bring quite a bit of rainfall to the eastern
portions of the forecast area early in the extended periods.
However, one caution is how extensive the dry slot interacts with
the conveyor belt and pushes the moisture further north and out of
our area. So, this all remains to be seen in how the storm system
winds down by the weekend.
As mentioned, with the cool pool over the area and potential for
showers, we will not see temperatures climbing much out of the 60s
through the first half of the extended periods. Eventually, as the
upper level low pulls out, some warm air advection will take place
and restore temperatures back into the 70s. Otherwise, overnight lows
will be consistently in the 50s.
&&
.AVIATION /00Z Wednesday THROUGH Sunday/...
Low across Lake Superior will spiral southward to the Ohio Valley
where it will linger for days. VFR conditions on the
fringes...but as we get some of the deeper moisture into the area
late morning/midday...Non-VFR conditions will take over...from
vsby issues in RA and/or from lowering ceilings. Western terminals
will likely be the focus for the steadier showers on Wednesday.
IFR possible in the heavier rain. Thunderstorms possible in the
afternoon. Winds will shift counter- clockwise around the dial
over the next 24 hours. Low confidence in the exact timing of the
impactful changes though.
OUTLOOK...Periods of non-VFR through Sunday.
&&
.MARINE...
Massive upper level and surface low will slowly work their way
southeast across the lake over the next 24 hours. The low will
continue to cause winds to gradually diminish overnight from west to
east. Will continue the small craft advisory in the west into the
evening and the east late tonight. We will likely need to reissue
the small craft advisory once again Thursday and continue it until
Friday when the winds finally start to diminish again. Otherwise,
lake will be quiet for the duration of the weekend.
As the upper level low settles in over the area, there will be a
chance for waterspouts through the rest of the week. This should
begin during the day tomorrow as the showers move into the local
area.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 3 AM EDT Wednesday for LEZ146>149.
Small Craft Advisory until 10 PM EDT this evening for
LEZ142>145.
&&
$$
SYNOPSIS...Jamison
NEAR TERM...Jamison/Kubina
SHORT TERM...Jamison
LONG TERM...Lombardy
AVIATION...Oudeman
MARINE...DJB/Lombardy
Area Forecast Discussion
National Weather Service Jacksonville FL
840 PM EDT TUE SEP 27 2016
.UPDATE...Radar shows scattered showers/isolated t-storms
limited to far eastern Marion county and far southern parts
of Putnam and Flagler counties. HRRR guidance suggests this
may continue there another hour or two before diminishing.
Otherwise...partly cloudy skies expected. Could be some
patchy early morning fog...but not anticipating anything
significant enough to include in public forecast as 00z
soundings show general decrease of dew points with height
just above the ground.
&&
.AVIATION...May see some patchy late night/early morning fog...
with MVFR vsbys at JAX, VQQ, and GNV. Otherwise prevailing VFR
expected.
&&
.MARINE...No significant changes planned in next CWF issuance.
Winds will be mostly offshore for the remainder of the week with
a cold front to move through the area on Thursday.
Rip Currents: Low risk of rip currents through Wednesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 70 89 67 88 / 10 40 30 10
SSI 72 87 72 88 / 10 40 40 20
JAX 69 89 70 88 / 10 40 40 20
SGJ 72 87 72 87 / 10 40 30 30
GNV 69 87 70 85 / 10 50 40 30
OCF 70 87 71 86 / 10 50 40 30
&&
.JAX Watches/Warnings/Advisories...
FL...None.
GA...None.
AM...None.
&&
$$
Wolf/Peterson/Shashy
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1003 PM EDT Tue Sep 27 2016
.SYNOPSIS...
An area of low pressure will move northeast just off the coast
tonight. A stalled cold front to the northwest will gradually
dissipate Wednesday and Thursday. Another cold front will
gradually move through the area over the weekend as low pressure
over the Ohio Valley moves northeast.
&&
.NEAR TERM /OVERNIGHT/...
As of 10 PM Tuesday...Latest sfc analysis shows weak low off the
NC coast this evening...and cold front extending from SW VA down
into the deep south. Latest radar imagery shows scattered showers
and thunderstorms moving into central NC. Could see this activity
make it into the coastal plain after midnight, though high res
models HRRR and NSSL WRF show bulk of precip weakening is it
pushes eastward. Isolated showers/tstm threat will persist
through overnight hours with moist unstable conditions and weak
short wave energy along with low moving northeast just off coast.
Will continue chance POPs inland and sc along the coast. Some
concern for fog inland sections overnight if there is some
clearing in areas that will receive rain this evening. Some patchy
dense fog may develop. Min temps from upper 60s inland to lower
70s coast.
&&
.SHORT TERM /WEDNESDAY/...
As of 400 PM Tuesday...Weak high pressure will be over area in
the morning in wake of low pressure moving off to northeast and
have lowered POPs to just lower chance early. Upper low dipping
into Ohio Valley will produce additional short wave energy across
area late morning through afternoon and area will return to warm
sector conditions as surface winds return to southerly as low
pressure develops to west. Scattered showers and tstms will
develop and some storms could be strong to marginally severe as
increasing instability and shear may result in wind gust threat.
Will carry higher chance POPs through afternoon. Max temps in the
low to mid 80s.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
As of 400 PM Tuesday...Minor update for slightly warmer temps
Sunday-Monday.
/Previous discussion/
As of 3 AM Tue...Unsettled through Thu then a bit drier by the
weekend.
Wed through Thu...Weakening cold front will cont over the region
Wed and Thu as big upr low conts to the NW. Axis of good moisture
will remain over eastern NC leading to at least chc of shra and
poss a few tsra. Best chcs will be inland Wed and have pops just
below likely. Precip may become a bit more sct into Thu and have
lower chc pops area wide. Temps close to seasonal for late Sept
with highs 70s to lower 80s and lows 60s inland to around 70
beaches.
Fri through Tue...The upr low to the NW will slowly move NE into
the weekend as sfc front conts to dissipate. Drier mid lvl air
will spread in from the W Fri with slight chc of shra over ern
portions of the area. Not much change Sat into Mon with mdls
keeping bulk of moisture near cst and offshore so will cont slight
pop imd cst and dry inland. Highs will cont near seasonal lvls
with upr 70s to around 80.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Short Term /through Wednesday/...
As of 10 PM Tuesday...VFR conditions at TAF sites will generally
persist into this evening with weak warm sector conditions between
low pressure offshore of SC and weak cold front approaching from
W-NW. Isolated showers/tstms possible overnight, with best chances
at PGV and ISO. Light winds and some clearing possible for inland
sites overnight and will continue to indicate MVFR conditions
developing with fog and stratus. IFR fog/stratus possible, with
best chances at PGV/ISO. Any fog and stratus should lift between
12-14z with VFR returning. Scattered showers and thunderstorms
expected to develop Wed afternoon.
Long Term /Wed night through Sunday/...
As of 3 AM Tue...Decent coverage of shra into Thu with poss some
isold trsa. The precip will lead to a few periods of sub VFR thru
Thu. Drier air will work in from the W Fri with decreasing chc of
shra and mainly VFR thru Sun...there will be threat of some late
night and early morning fog and stratus with light winds late
week.
&&
.MARINE...
Short Term /through Wednesday/...
As of 10 PM Tuesday...Latest obs show NE-SE winds 5-10 kt and
seas 3-5 feet. No sig changes made to previous forecast at this
time. Will continue SCA for outer portions of central waters, for
some gustier winds around the low allowing seas to build to 6
feet...though still not quite sure if elevated seas will
materialize. Low moving NE just offshore will result in current
E-SE winds backing to NE and N overnight with speeds rest of
waters mainly below 15 KT and seas 2-4 FT. Weak high pressure over
area in the morning will move offshore in afternoon with winds
returning to SE-S 10-15 KT with seas remaining 2-4 FT.
Long Term /Wednesday night through Sunday/...
As of 3 AM Tue...Light mainly NNE winds in wake of low early Wed
quickly returns to light S or SE later in the day with weakening
cold front to the W. Predominately S to SW winds 15 kts or less
Thu into Fri as dissipating front drifts to the cst. Light winds
Sat with the front or whats left of it near cst. Seas thru the
period will be mainly 2 to 4 feet...could flirt with 5 ft at times
far outer waters.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Beach Hazards Statement from 8 AM EDT Wednesday through
Wednesday evening for NCZ103.
MARINE...Small Craft Advisory until 8 AM EDT Wednesday for AMZ152-154.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM/CQD
SHORT TERM...JBM
LONG TERM...RF/JBM
AVIATION...RF/JBM/CQD
MARINE...RF/JBM/CQD
Area Forecast Discussion
National Weather Service Marquette MI
735 PM EDT Tue Sep 27 2016
.SHORT TERM...(This evening through Wednesday)
Issued at 352 PM EDT TUE SEP 27 2016
12Z raobs/latest wv imagery and RAP analysis show a closed upr lo
dropping slowly swd acrs Lk Sup. Deep cyc, cool flow arnd this
disturbance in concert with deep mstr depicted on the 12Z INL raob
and some dynamic forcing are generating some showers over the cwa
this aftn. With the cld cover and h85 temps arnd 4C /Lk Sup temps
range fm about 10-15C/, there is some lk enhancement to the pcpn
as temps are holding in the upr 40s to mid 50s. There is some drying
evident wrapping arnd the closed lo associated with large scale
subsidence/deep lyr qvector dvgc on the nrn flank of that feature
that is tending to diminish the shower coverage over much of Lk Sup
and the nrn land cwa.
Tngt...Closed lo fcst over scentral Lk Sup early this evng is
progged to sink steadily swd to over scentral Lk MI by 12Z Wed, with
large scale subsidence/deep lyr qvector dvgc/mid lvl drying
overspreading Upr MI fm the n. With these trends in mind, expect the
showers to become more sct by later tngt. Although the h85-lk
temp difference wl be marginal for lk effect pcpn, lingering llvl
mstr and the sharp cyc flow should still support some showers. Since
winds wl also shift steadily to a more cyc ne direction during
the ngt with the passage of the sfc lo to the s of the cwa, expect
the lk effect showers to become most nmrs over the w and ncntrl cwa,
where this ne flow wl upslope. There could still be some waterspouts
late this aftn into the evng hrs over mainly the scentral portion
of the lk to the Keweenaw under lingering deeper mstr/area of lighter
winds near the sfc lo center and where the hier res models indicate
mucapes as hi as 500-750j/kg over the somewhat warmer nearshore
waters. But rising hgts/mid lvl drying and lowering mucape/hier winds
on the nrn flank of departing sfc lo wl diminish this threat after
the evng. The arrival of the ligher winds closer to the track of the
sfc lo wl also bring the threat of waterspouts to the Lk MI
nearshore waters tngt.
Wed...With continued hgt rises/mid lvl drying/lowering subsidence
invrn/slowly weakening cyc nne flow to the n of the closed lo
sinking into the Lower Lks, the shower coverage wl diminish. The
best chc for more persistent showers wl be over the hier terrain
of the w and ncentral cwa impacted by upsloping and over the far
se on the nw edge of some lingering deeper mstr closer to the
departing closed lo to the sse. Even though the shower coverage wl
diminish, fcst llvl mstr/sfc obs upstream sug a good deal of lo clds
wl linger and limit diurnal temp recovery.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 332 PM EDT TUE SEP 27 2016
High pressure building in from the northwest Wed night and Thu
should end showers and allow for decreasing clouds. The NAM and GFS
soundings indicate that there could be some near sfc moisture
trapped beneath strengthening subsidence inversion Wed night into
early Thu which could maybe lead to some stratus formation for
locations favored by upslope ne flow. Models indicate there should
be enough wind/mixing to preclude fog formation so removed patchy
fog for western counties Wed night into early Thu. Cut-off mid-upper
level low pressure system remaining nearly stationary over the TN
River Valley should maintain dry conditions through Fri. Expect mins
Wed night and Thu night to range from lower 40s interior west to mid
50s near Lake Superior in onshore ne flow. H85 temps of 7-8C should
support inland max temps mainly in the mid to upper 60s on Thu and
H85 temps of 8-10c should support inland max temps in the upper 60s
to lower 70 on Fri. Continued onshore ne flow will keep max temps
cooler both days near Lake Superior in the lower to mid 60s. Influx
of mid-Atlantic moisture wrapping around cut-off low could lead to
increase in mid-level clouds on Fri over the southeast half of U.P.
Models in general agreement with mid-upper low moving slowly
northward into the Ohio Valley/Great Lakes region Fri night into the
weekend and getting eventually caught back in westerly mid-latitude
flow in response to deepening mid-upper trough over the West Coast.
Continued influx of deeper mid-Atlantic moisture wrapping around low
and increasingly cyclonic ne flow will lead to increased chances for
rain beginning Fri night and continuing into the weekend especially
for the east half of Upper Mi closer to the movement of mid-upper
low.
Model trends indicate closed low slowly moving east toward New
England Sun night into Mon as western CONUS trough moves slowly
eastward. Should see improving weather across Upper Michigan Sun
night into Mon as upper level ridging from west becomes main feature
again. Expect increasing clouds from the west late Mon night into
Tuesday as mid-level moisture increases with approach of mid-upper
trough from western CONUS and associated sfc trough from the Plains.
Some increase in mid-level q-vector convergence ahead of the trough
could also bring some light rain into west and central Upper Mi on
Tue. Not surprisingly the 12z GFS is showing its typical bias with a
quicker advance of trough than the 12z ECMWF so will include some low
chance pops for rain over west and central counties mainly Tue
afternoon.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 735 PM EDT TUE SEP 27 2016
A low pressure system centered over central Lake Superior will
continue to slowly drift to the south across the western Great Lakes
region overnight. This feature will produce IFR and low end MVFR
conditions at all three TAF sites overnight. IFR conditions favored
at KIWD due to persistent moist upslope flow off the lake. KSAW will
also see upslope flow developing and should see ceilings drop to IFR
for a time after 8Z. With winds expected to pick up at KCMX, enough
mixing to occur to keep cigs at MVFR but cannot rule out a brief
period of IFR there. KSAW may see a brief moment of VFR early in the
forecast as the low passes overhead but will quickly return to MVFR
and possibly IFR. As the low continues to drop south on Wednesday,
drier air will start infiltrating into the region and will bring
about slightly improving conditions at KIWD and KSAW with KCMX
becoming VFR by the afternoon.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 332 PM EDT TUE SEP 27 2016
As low pressure over eastern Lake Superior weakens and sinks slowly
south of the area through Wednesday, the pressure gradient over the
lake will gradually slacken causing north-northeast winds to 30
knots tonight over west and north central Lake Superior to diminish
to 20 to 25 knots on Wed. There could be some gale gusts to 35 knots
tonight mainly over the western half of Lake Superior. With the slow
approach of trailing high pressure, the winds will continue to
diminish late Wed into the weekend with lighter east to northeast
winds under 20 kts expected.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...KC
LONG TERM...Voss
AVIATION...RJT
MARINE...Voss
forecast discussion -- The models do not agree beginning Saturday, with
different tracks for the offshore upper low giving widely divergent
weather solutions over Washington. The GFS moves a secondary upper
low southeast into Oregon, making Saturday afternoon through Sunday
morning a wet period. The Canadian model keeps the low further
offshore, with mainly mountain showers Saturday and a surprisingly
dry Sunday and Monday. The Euro is between the two and keeps rain
confined to mainly western sections. The GFS is wetter than the
other two models on Monday and Tuesday. The upshot is a fair amount
of uncertainty through the extended period. For the forecast have
kept a chance of showers in every period, with mountain showers
likely Saturday night and Sunday. It is not going to rain every
period, but everywhere will probably get some rain at some point
during the Saturday to Tuesday period. Burke
&&
.AVIATION...Southwest flow aloft. Low level northerly flow. The air
is stable and dry except for some coastal stratus and fog that will
develop overnight and some valley fog that should form in the
interior river valleys. Otherwise it will be mostly clear with just
that strip of cirrus over NW Wa tonight.
KSEA...Clear skies except for a little cirrus, and a northerly
breeze. The wrfgfs and hrrr do not show any fog or low clouds for
Seattle Wednesday morning.
&&
.MARINE...High pressure offshore and to the north of the area with
lower pressure inland and to the south will give northerly breezes.
A small craft advisory remains in effect for the coastal waters and
extends through Wednesday afternoon. A weather system should reach
the area Friday and over the weekend.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 5 PM PDT Wednesday for Coastal Waters
From Cape Flattery To James Island 10 To 60 Nm-Coastal
Waters From Cape Flattery To James Island Out 10 Nm-Coastal
Waters From James Island To Point Grenville 10 To 60 Nm-
Coastal Waters From James Island To Point Grenville Out 10
Nm-Coastal Waters From Point Grenville To Cape Shoalwater
10 To 60 Nm-Coastal Waters From Point Grenville To Cape
Shoalwater Out 10 Nm.
&&
$$
www.weather.gov/seattle
You can see an illustrated version of this discussion at
www.weather.gov/seattle/gafd/latest_webafd.html
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
944 PM EDT TUE SEP 27 2016
.UPDATE...
CONVECTION HAS SETTLED DOWN SIGNIFICANTLY THIS EVENING...WITH JUST
A FEW ISOLATED CELLS STILL AROUND THE LAKELAND AREA AS OF 930 PM.
CONTINUE TO WATCH A DEFINED CONVECTIVE OUTFLOW BOUNDARY PUSH BACK
TO THE WEST THROUGH THAT MAY STILL HAVE POTENTIAL TO POP AN
ISOLATED SHOWER OR STORMS DURING THE NEXT 1-2 HOURS ACROSS
HILLSBOROUGH/PINELLAS/PASCO COUNTY. THIS BOUNDARY HAS EXITED THE
COAST DOWN TOWARD MANATEE AND SARASOTA COUNTIES...SO ANY ISOLATED
CONVECTION THAT FAR SOUTH SHOULD NOW OCCUR OVER THE MARINE ZONES.
THIS BOUNDARY SHOULD RUN OUT OF GAS BY MIDNIGHT...AND ALLOW A THE
LIGHT SYNOPTIC SOUTHWESTERLY FLOW TO RETURN TO ALL AREAS.
A WEAK UPPER SHORTWAVE APPROACHING FROM THE WEST LATER TONIGHT IS
EXPECTED TO INCREASE THE POTENTIAL FOR SCT SHOWERS AND STORMS OVER
THE COASTAL WATERS...MAINLY TO THE NORTH OF TARPON SPRINGS...AND A
FEW OF THESE SHOWERS MAY REACH THE NATURE COAST BY DAWN.
OTHERWISE...MOSTLY DRY OVERNIGHT WITH TEMPS MAINLY IN THE 70S.
Just realized everything above I typed in ALL CAPS. Old habits
really do die hard. Have a great evening everyone and enjoy your
Wednesday.
&&
.Prev Discussion... /issued 231 PM EDT TUE SEP 27 2016/
SYNOPSIS...
Ridge axis of weak high pressure extended across the Florida Straits
with westerly low level flow across forecast area. Visible satellite
and surface observations showed sea breeze front from Inverness to
Sarasota then down to Naples. Isolated showers were found along the
front. Water vapor loop showed weak upper level low in east central
Florida with drier air wrapping into the forecast area. Best chance
of afternoon storms to be in Highlands County as it is closer to
the deep layer moisture across south Florida.
SHORT TERM (Tonight and Wednesday)...
Will keep a small chance of thunderstorms in forecast 00-03Z east of
Highway 27 in Polk and Highlands counties and in Punta Gorda and
Fort Myers as HRRR model has gust front from Highlands County
convection heading back to the coast.
Large and stacked upper level low centered near eastern Lake
Superior is forecast to drift south into Indiana Wednesday. Our
forecast area will be on the southern end of the cyclonic flow
aloft. Weak impulses in this flow combined with a stalled front in
the Florida Pan Handle will bring scattered showers and storms to
the Nature Coast late tonight and will continue through the
afternoon. Expected cloud cover and sea breeze will keep highs in
the mid 80s rather than the upper 80s in this area. Elsewhere,
westerly low level flow will be a bit stronger Wednesday with the
sea breeze front moving well inland. Best chance of storms will be
east of Interstate 75 from 18-21Z.
MID TERM/LONG TERM (Wednesday Night-Tuesday)...
A mid/upper level low meanders between the Great Lakes and the
Tennessee Valley through most of the weekend. The low nudges a
weakening frontal boundary out of the Deep South...through northern
FL on THU...then into central FL where it dissipates during FRI. A
ridge of high pressure from the Atlantic initially across south FL
slides off to the east. The front settles in with drier and more
stable air behind it...with limited to nil rain chances from around
the I-4 corridor northward. South of there scattered showers and
storms will continue. Some deeper moisture will begin to creep back
north SAT. Temperatures will run around normal for the highs.
However lows for the nature coast will be just below normal while
lows south of I-4 stay on the warm side.
On SUN the upper low tracks across the lower Great Lakes to NY or
southwest Quebec by MON. For TUE the low remains near NY (GFS) or
pushes east to the Canadian Maritimes (ECMWF). At the surface...
Atlantic high pressure builds back in across and north of the state
as a low approaches... near the Bahamas (GFS) or central Cuba
(ECMWF)...at the very end of the period. Moisture will significantly
increase and spread northward as low level flow takes on an easterly
component. Showers will be scatted to numerous with isolated to
scattered thunderstorms. High temperatures will be near to a bit
above normal. The lows will be a degree or two above normal.
The last day or so of this forecast could change depending upon the
exact track of the low...in the Bahamas or near Cuba?
AVIATION...
VFR conditions for most of the next 24 hours. Best chance for
afternoon storms this afternoon and Wednesday afternoon will be east
of the terminals as a westerly low level flow pushes the Gulf Coast
sea breeze inland.
MARINE...
A cold front will move into the coastal waters Thursday and will
wash out. This will bring scattered showers and thunderstorms to the
central and northern coastal waters through Thursday. Easterly flow
develops for the weekend with late afternoon and overnight showers
and storms.
FIRE WEATHER...
Relative humidity is forecast to remain above critical thresholds
through the week, with no fire weather concerns expected.
&&
.Preliminary Point Temps/PoPs...
TPA 76 88 75 87 / 20 30 40 40
FMY 74 89 75 88 / 20 30 30 40
GIF 73 89 73 87 / 20 50 20 50
SRQ 76 87 76 87 / 20 30 40 50
BKV 72 87 72 86 / 20 50 40 50
SPG 78 87 77 86 / 20 30 40 50
&&
.TBW Watches/Warnings/Advisories...
FL...Beach Hazards Statement through Thursday evening for
Coastal Manatee-Coastal Sarasota.
Gulf waters...None.
&&
$$
UPDATE...Mroczka
PREVIOUS DISCUSSION...NOAH/RUDE
Area Forecast Discussion
National Weather Service Saint Louis MO
312 AM CDT WED SEP 28 2016
.SHORT TERM... (Through Late Tonight)
Issued at 311 AM CDT Wed Sep 28 2016
Cold front is getting ready to enter the northern CWA, and will push
rapidly across the CWA by mid morning per the RAP. Regional radars
are showing that the scattered showers are currently staying close
to an upper low over northern Illinois. May still be a slight
chance of showers early across the Illinois counties as the cold
front moves through the area as the RAP is showing some weak mid
level ascent and low level convergence along the front. HRRR
reflectivity is showing some weak returns over south central
Illinois along the front. Highs today will be much cooler with cold
air advection behind the front. Went with a compromise of MOS highs
which is supported by the SREF ensemble temperatures.
Expect mainly dry weather tonight with some clouds lingering over
Illinois in close proximity to the upper low which will be moving
south across Indiana. Expect lows tonight to fall to close to the
agreeable MOS lows.
Carney
.LONG TERM... (Thursday through Tuesday)
Issued at 311 AM CDT Wed Sep 28 2016
Guidance has been consistently moving the upper low a bit
further west for the past several runs. It should be near the
Indiana/Kentucky border Thursday morning and it will spin over the
Ohio Valley at least through Saturday. The low starts lifting out on
Saturday night according to medium range guidance and should be
swallowed up into the longwave pattern over New England and
southeast Canada by Monday evening. For the Mid-Mississippi Valley
this means north-northwest flow through the depth of the troposphere
through Saturday. 850mb temps hover in the 7-10C range through
Sunday which mixes down to upper 60s to mid 70s each day.
Guidance is spitting out some light QPF primarily during the
afternoon and evening for Thursday through Saturday mostly along and
east of the Mississippi River. This looks reasonable given the
strength of the low and the multiple lobes of vorticity which rotate
around it through the weekend. Additionally, isentropic fields show
a nice feed of moisture on the cool conveyor belt off the Atlantic
with c-defs less than 10mb on the 295K and 300K isentropic surfaces
feeding back into the Mississippi Valley. Since models are in good
agreement now with this QPF and the aforementioned moisture feed,
will go ahead and bump up PoPs across parts of eastern Missouri and
Illinois for Thursday through Saturday. Will keep Sunday dry for
now with the low moving off and removing the moisture feed from the
east. Am continuing to lean heavily on cool MOS numbers and 850mb
mix down temperatures for highs through Saturday rather than
standard blended guidance due to more extensive cloud cover and
probable showery precip. Should see fewer clouds Sunday with an
upper ridge building overhead...and then return flow Monday and
Tuesday with temperatures rising back above normal.
Carney
&&
.AVIATION... (For the 00z TAFs through 00z Wednesday Evening)
Issued at 628 PM CDT Tue Sep 27 2016
VFR conditions are expected for at least the first 0-6 hours of
the TAF pd and probably longer. There is a slim chance that rain
showers could develop invof a cold front between 09-15z near
KUIN, KSTL, KSUS, and KCPS, but confidence is too low to include
pcpn in the TAFs attm. Winds will become northwesterly to
northerly after fropa. The tighter pressure gradient near the
front will keep sustained winds AOA 10 kts with gusts up to 20 kts
during the aftn.
Kanofsky
&&
.PRELIMINARY POINT TEMPS/POPS...
Saint Louis 68 54 69 58 / 10 5 10 10
Quincy 63 49 69 55 / 5 10 10 10
Columbia 67 48 70 52 / 5 0 10 10
Jefferson City 69 49 70 53 / 5 0 10 10
Salem 67 50 67 55 / 30 10 30 30
Farmington 69 47 66 54 / 10 0 10 10
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Seattle WA
305 AM PDT Wed Sep 28 2016
.SYNOPSIS...Dry southwest flow aloft will bring mostly sunny weather
today through Friday, except for patchy morning low clouds and fog.
A large upper level trough will bring showery and cooler weather
Friday night through the weekend. Unsettled weather will likely
continue early next week in northwest flow aloft.
&&
.SHORT TERM...Dry southwest flow aloft will continue over W WA
today through Thursday. Onshore flow will remain weak, but still
have just enough strength to make isolated low clouds or fog
possible each morning.
The large upper level low W of the B.C. coast and near 52N/140W at
09Z/2 AM will continue moving SSE the next few days, eventually
reaching 45N/130W or W of the Oregon coast on Friday. As the low
nears the area on Friday, the flow aloft over W WA will shift to
southerly. The 00Z models were in good agreement through Friday and
keep the area dry through Friday afternoon. Model RH progs and time-
height sections kept the air mass dry enough through Friday to call
it mostly sunny. I kept a slight chance of showers over the Cascade
crest Friday afternoon, even though the 00Z models were backing away
from the showers. High temperatures will gradually cool through
Friday as the large low approaches the region and 500 MB heights
fall. Kam
.LONG TERM...The 00Z GFS ECMWF and Canadian solutions begin
diverging a little Friday night. The models show a shortwave trough
ejecting out of the large trough just offshore sometime Friday night
or Saturday but differ on timing. The ECMWF is the fastest and the
Canadian slowest. Depending upon how fast the shortwave ejects,
showers may not make it very far inland Friday night, but should
spread across W WA on Saturday.
The feature that is kicking the shortwave inland is another small
low dropping S into the bottom of the main trough. The main trough
along with the small low eventually move inland across the region on
Sunday. This could end up being the wettest day of the period. The
air mass will cool significantly this weekend allowing mountain snow
levels to drop down to around 5000 feet. NW flow aloft develops
early next week behind the departing upper level trough. It looks
like there could be one or more weak shortwaves embedded in the flow
so the chance of showers will continue. Kam
&&
.AVIATION...Southwest flow aloft. Low level northerly flow. The air
is stable and dry. Some patchy valley fog may for around daybreak
and there is a chance that some fog or low clouds will set up around
Grays Harbor, although the hrrr has shown less now. There is some
cirrus passing over early this morning from a weak upper trough.
KSEA...Some cirrus and a northerly breeze. Only the sheltered
valleys away from the metro area have a chance to see any fog.
&&
.MARINE...High pressure offshore and to the north of the area with
lower pressure inland and to the south will give northerly breezes.
A small craft advisory remains in effect for the coastal waters but
as a weak low drifts toward the area the gradient will decrease
tonight and Thursday. By the end of the week there should be a slow
moving area of low pressure just offshore and some rain is likely
for the weekend.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory coastal waters.
&&
$$
www.weather.gov/seattle
You can see an illustrated version of this discussion at
www.weather.gov/seattle/gafd/latest_webafd.html
Area Forecast Discussion
National Weather Service Albany NY
1022 AM EDT WED SEP 28 2016
.SYNOPSIS...
High pressure will ridge in from eastern Quebec today
into tonight with mainly dry and seasonable temperatures...except
for some isolated showers or sprinkles across western New England. A
slow moving low pressure system near the Ohio Valley will gradually
move towards New York and New England with an increase of scattered
showers Thursday into Friday with cooler temperatures.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Light southeast low level flow has drawn some moisture and cloud
cover westward from New England and is spreading up the eastern
bank of Hudson Valley as well. There is an axis of clearing
between areas of clouds but this will fill in from time to time
for intervals of overcast and partly sunny throughout the Hudson
Valley through this afternoon. The clouds will slowly spread into
the central Mohawk Valley through the day and even into the
southern Adirondacks and Lake George area. Have adjusted
temperatures down a degree or two in western New England and a few
other minor adjustments in other areas. have adjusted the cloud
cover a bit but mesoscale models including the HRRR are not
resolving the current cloud cover much of at all, so the evolution
of cloud cover through this afternoon will have to be watched
carefully. The prospects for isolated showers this afternoon seems
to have diminished and have lowered rain chances this afternoon. The
previous AFD has some more details and is below...
A cutoff low continues to swirl over the western Great Lakes
Region this morning. The cutoff will slowly descend
south/southeast into the Midwest today. Meanwhile, the Northeast
will be under the influence of southwest flow aloft. A stationary
front remains off the New England and East Coast with a sfc
anticyclone ridging in from east/northeast Quebec. The return,
onshore flow from the sfc high will focus some cloud cover along
the east facing slopes of the southern Greens, Berkshires and
Litchfield hills today, but also spreading west through the
afternoon. Most of the forecast area will remain dry.
With the weak backdoor style front pushing southwest from
northern New England, H850 temps will range from +6 to +7C over
southern VT to +9C to +10C over the Catskills and Mid Hudson
Valley. Highs will be near normal in mid and upper 60s in the
valley areas, except the CT River Valley in southern VT where
upper 50s to lower 60s are likely and mid 50s to lower 60s will be
common over the mountains. Northeast to southeast winds will
prevail at 5 to 15 mph.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
Tonight...Much of the evening period should end up dry with the threat
of isolated to scattered showers moving in from the south and west
with an impulse moving north/northeast from the cutoff cyclone
centered over IN towards daybreak. The low level baroclinic zone
between the large anticylone near southeast Quebec/Northern
ME...and the double barrel low pressure system over the OH Valley...and
Mid Atlantic Region strengthens. The best chance for scattered
showers will be from the Capital Region south and east before day
break. Lows will range from the mid 40s to lower 50s across the
forecast area.
Thu-Thu night...The cutoff low actually wobbles further
south/southeast towards KY/TN. A short-wave pivots around the
cyclone. There is still quite a bit of disparity in the
NAM/EC/GFS/Canadian Guidance on how far north and east the short-
wave impacts the region. The GFS/ECMWF mainly have locations from
the Mohawk Valley/southern Dacks/Capital Region having a bout of
showers...and then a decrease in them during the afternoon and
early evening. Previous CSTAR research has documented that cutoffs
are always challenging to forecast in terms of the timing of rain
and the amounts. This trend continues with this event. Chance pops
were mainly used from the Mohawk Valley/Capital Region south and
west with slight chc pops or no pops further north east with the
ridge trying to still build in. Temps will be seasonable and
slight cooler than previous days with upper 50s to lower 60s over
the elevated terrain...and mid and upper 60s in the valley areas.
Lows Thu night will be similar to the previous night with mid 40s
to lower 50s in the maritime air mass.
Fri-Fri night...The trend increases for more scattered showers on
the guidance...as the cutoff continues to spin over OH Valley.
A weak wave or inverted trough sets up over the New England/Mid
Atlantic coast with better moisture advection coming in from the
south and east. High chc pops were used with some areas of likely
values. The fetch of Atlantic moisture increases with a
strengthening east to southeast H850-700 low-level jet. We leaned
closer to the cooler GFSMOS guidance with lots of clouds and
periods of showers. Highs should be below normal with mid 50s to
lower 60s over the forecast area. Lows will show little change
from the previous days with mid 40s to around 50F north and east
of the Tri Cities...and upper 40s to mid 50s south and west.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Biggest forecast challenge during the extended period with be
regarding the exact track and timing of an upper level low and the
placement of precipitation around this feature. The upper level low,
which looks to be situated west of the area over the weekend, will
track over and across the region for early next week.
During the weekend, the upper level low will be situated somewhere
over the Midwest/Ohio Valley Region. With a southerly flow ahead of
this system, plenty of moisture will be advected into the area from
the Gulf of Mexico and western Atlantic Ocean. PWAT values look to
climb to around 1.50 inches or higher (at least 1 and up to 3 STD
above normal). With the cyclonic flow in place, some showers will
be possible over the weekend, especially on Saturday and across
southern areas, when the low and mid level flow is out of the S-SE,
which will promote upslope flow into the Catskills. Although there
could be some brief burst of heavy rainfall, any rainfall is much
needed across the region. On and off showers look to occur each day
with a mostly cloudy sky.
With plenty of clouds in place, there won`t be a large diurnal range
each day. Temps over the weekend look to reach the 60s during the
day with 50s at night.
As the upper level low starts to shift eastward, the chance for
precip will start to decrease from west to east. Just when the
threat ends will depend on when the upper level low exits to the
east, which could be as early as Monday night, as shown in some
model solutions. Once the upper level low exits, heights look to
rise, as ridging builds in for the mid week period. Will continue
to allow a chance for showers into Monday, but will decrease for Mon
night into Tuesday. High temps look to reach the mid to upper 60s
for Mon/Tues, with lows in the mid 40s to low 50s.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
Some low clouds/mist has been ongoing this morning at all TAF sites.
With sunrise now underway, daytime heating/mixing will begin and
helps dissipate any lingering fog/mist/low clouds. Will allow for
some MVFR/IFR conditions for the next few hours until it can fully
dissipate.
After the morning fog/mist, VFR conditions are expected for much of
the day for the valley sites of KGFL/KALB/KPOU with sct-bkn cigs at
3500-5000 ft. Meanwhile, flying conditions look primarily MVFR at
KPSF with bkn cigs at 2000-3000 ft there, thanks to upslope flow.
East to southeast winds will be 5-10 kts, with the strongest winds
occurring at KALB.
By this evening, some MVFR cigs will develop at KPOU thanks to
increasing low level moisture and MVFR conditions look to continue
at KPSF. VFR conditions may continue for a little bit longer at
KGFL/KALB, although ceilings will start to lower and cloud coverage
will also increase for these sites as well. East to northeast winds
will be around 5 kts for tonight. It should be dry through much of
the night for all sites.
Outlook...
Thursday through Monday: Moderate Operational Impact. Chance of SHRA.
&&
.FIRE WEATHER...
High pressure will ridge in from eastern Quebec today
into tonight with mainly dry and seasonable temperatures...except
for some isolated showers or sprinkles across western New England. A
slow moving low pressure system near the Ohio Valley will gradually
move towards New York and New England with an increase of scattered
showers Thursday into Friday with cooler temperatures.
The RH values will lower only to 50 to 70 percent this
afternoon...and have an excellent recovery to close to 100 percent
tonight. The RH values will remain elevated in the 55 to 75
percent range Thursday afternoon.
The winds will vary from the northeast to southeast at 5 to 15mph
on today. They will be north to northeast at 5 to 15 mph tonight
into Thursday.
&&
.HYDROLOGY...
No widespread hydro issues are expected the next 5 days ending on
Sunday.
Isolated to scattered showers may return tonight into the weekend
with a cutoff cyclone. The amount of rainfall is uncertain during
the stretch, but totals of a quarter to three quarters of an inch
will be possible in some locations depending on the track of the
cutoff. At this time, the best potential for rainfall will along
and south of Interstate 90 into the weekend. Locations further
north and east may only have lights amounts of rainfall...mainly
under a quarter of an inch.
The U.S. Drought Monitor released on September 22nd shows drought
conditions have changed very little across the region. The next
issuance will be on September 29th. For details visit:
www.drought.gov
For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our
website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...Wasula
NEAR TERM...NAS/Wasula
SHORT TERM...Wasula
LONG TERM...Frugis
AVIATION...Frugis
FIRE WEATHER...BGM/Wasula
HYDROLOGY...BGM/Wasula
Area Forecast Discussion
National Weather Service State College PA
1027 AM EDT Wed Sep 28 2016
.SYNOPSIS...
A multi-day heavy rain event is probable across far south-central
Pennsylvania beginning later today and continuing tonight through
Thursday. Flooding impacts are likely across the southern half of
central PA...but impacts may be lessened to some extent by dry
antecedent conditions. Unsettled weather with occasional lighter
rain showers will persist into the weekend with a gradual drying
trend by early next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Increasing southeast flow aiding expansion of lower clouds from
the Mason Dixon line northward into the Laurel Highlands and parts
of the South Central and Central mountains and Ridge and Valley
region at mid morning. Deep easterly flow with long over water
fetch from the Western Atlantic is pushing low clouds westward
from the Hudson River Valley into nrn NJ and the Catskills as
well. Persistent showers ongoing well south of my area from areas
south of DC to the Chesapeake and HRRR shows this area pivoting
and lifting into the south central mountains and lower Susq by
late afternoon. Earlier light showers which trekked north of the
Mason Dixon line have dissipated due to dry air entrainment.
Clouds will continue to increase from south to north throughout
the day as southeast flow increases and boundary layer moisture
deepens. Model guidance still shows the main surge in rain
coverage and intensity later tonight into Thursday which
corresponds with arrival of stronger dynamical forcing and
strengthening E-SE upslope low level flow. Showers with locally
heavy banded and orographics will increase by late evening and
overnight across the southern third to half of central PA.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
*Flood Watch in effect for the Laurel Highlands, South Central
Mountains and southern portions of the Central Mountains midnight
tonight through Friday morning.
*Heavy rainfall event probable over far south-central
Pennsylvania on Thursday
*Flooding is likely however high impacts may be mitigated by dry
antecedent conditions
Heavy rain event is expected to be ongoing over south-central PA
on Thursday. An enhanced convergence axis/frontal zone is progged
to develop on the east side of an upper low meandering over the
OH/TN Valley, tapping into deep moisture/high PW air off the
Atlantic Gulf Stream via anomalous east/southeast low level jet.
The heavy rain axis is progged to gradually pivot to the southwest
with time oriented within moderate excessive rain outlook area from
southwest PA near the Laurel Highlands southeast into Northern
VA/D.C. area. The strength of the upslope flow and high PW
transport along with some elevated instability should provide an
environment for efficient rainfall processes.
WPC QPF blend again favored a slight shift in QPF to the
southwest but maintained a broad area of 2-4" with localized 4-6"
possible. Keep in mind these amounts are over a 36+ hour period
with preceding dry conditions and near to below normal
streamflows. Therefore the dry antecedent conditions may
limit more significant flooding/runoff issues. Still expect
flooding to result from long duration event...and have issued
Areal Flood Watch for Laurel Highlands, South Central Mountains
and southern portions of the Central Mountains for late tonight
through Friday morning. Will continue to highlight potential flood
risk in HWO elsewhere.
The upper low is fcst to drift back to the west/NW into the OH
Valley on Friday before slowly moving to the ENE across the Lower
Great Lakes through the weekend. We should continue to see periods
of showers on Friday but rainfall amounts will be much lower and
less organized.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Model guidance still suggests unsettled conditions over the
weekend with a gradual decrease in the chance for shower. Temps
still holding close to seasonal normals as we turn the calendar to
October.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
Today will be the last VFR day before more showery and cloudy
conditions develop later Wednesday Night into Thursday with
widespread reduced conditions likely. MVFR cigs will increase by
this afternoon and evening...with IFR reductions developing south
to north late tonight and lasting through Friday.
Outlook...
Thu-Fri...Widespread showers/cig reductions.
Sat...Reductions possible with a chance of showers.
Sun...Improving conditions.&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Flood Watch from late tonight through Friday morning for
PAZ024>028-033>036-056-063>065.
&&
$$
SYNOPSIS...Steinbugl
NEAR TERM...DeVoir/Steinbugl
SHORT TERM...Steinbugl
LONG TERM...Steinbugl
AVIATION...DeVoir/Gartner
Area Forecast Discussion
National Weather Service Wilmington NC
1058 AM EDT Wed Sep 28 2016
.SYNOPSIS...
A cold front approaching from the west will stall through mid-
week before moving across the area Thursday into Friday. Dry high
pressure will build into the area by the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1000 AM Wednesday...Anomalously strong upper low centered near
Lake Michigan will deepen and sink slowly SE through tonight.
Beneath this feature, a stationary front will meander across
western/northern NC and into VA, keeping the local area firmly
within the warm sector today. While this will create temperatures
well into the 80s this aftn, about 5-8 degrees above normal for late
September, it will also allow humidity to increase and create an
environment ripe for convection.
SPC has placed the i-95 counties in a MRGL risk for today, and while
total storm coverage is not expected to be widespread, any
individual storms will have the potential to produce a strong wind
gust. The combination of warm temperatures and high humidity will
drive SBCape to 2500 J/kg, which will combine with subtle height
falls, PWATS to 1.5 inches, and 20-25 kts of 0- 6 km shear to
produce that aforementioned isolated strong wind threat. Highest POP
will be featured along and west of i-95, which is agreed upon by
both the HRRR and NSSL 4km WRF, and makes sense as it is closest to
the upper low and along a moisture gradient. Heavy rain will also be
possible in stronger storms, but motion should be great enough to
prevent any significant flooding unless several storms pass across
the same area.
This evening and tonight, a shortwave will move out of the gulf
along the periphery of the upper low and overhead the CWA. This will
likely bring the best chance for showers with isolated tstms to the
eastern portion of the CWA, but no severe is expected tonight. Mins
will remain above normal for the time of year, dropping only to
around 70.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 345 AM Wednesday...Of the 2 days, Thu will be the wetter of
the 2 and exhibit the higher POPs. The main feature will be the
cutoff low making its furthest southern positioning across the
Central Appalachians. Thursday will feature embedded and stronger
mid-level s/w trofs rotating around this cutoff low. The 1 Thu
morning moves NE of the FA with the eastern 1/3 to 1/2 seeing
ongoing convection at the start of the day, moving out of the FA
by late morning. The next s/w rotating around and closer to the
cutoff low, will help push a dry slot across portions of the FA
late Thu aftn and night. With it not entirely thru the FA, will
keep a POP for the far eastern portions of the ILM CWA Thu night
into Fri. Finally, the models indicate the dry slut will finally
shunt the remaining moist air off the Carolina coasts by late
Friday. Improving wx conditions across the FA during Fri into Fri
night. Max/Min Temps, stayed closer to a consensus with a lean
toward the MET mos guidance based on its decent performance the
past couple days.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 3 AM Tuesday...Despite the fact that the long term begins with
an impressively large cutoff to our west the weather will be pretty
quiet. The reason for this is that we will be in the dry slot of the
occluded surface low to our NW and the deep moisture will be off the
coast. Sunday and Monday as the weakening front pushes through some
of this moisture may get drawn back to the coast for some minor rain
chances-all while temperatures remain close to their seasonable
norms. The front washes out by Monday leaving behind a weak surface
pattern while mid level heights build. There will still be no real
forcing for precipitation and no low level thermal advection to
change temperatures much from the values earlier in the period.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
As of 12Z...Patchy IFR cigs are W of KFLO while a small area of MVFR
cigs is affecting KILM. Buffer soundings suggest little chance of
sub-VFR at any terminal after 12Z. Will likely include MVFR cigs
around 2k feet at KILM through 13Z, and will need to watch KFLO for
the next hour or two.
Despite ample lift this morning, hi-res progs and MOS guidance are
not indicating much in the way of any precipitation at the coastal
terminals. Will include VCSH at KFLO/KLBT by mid-morning where MOS
guidance is indicating a higher chance of development. This
afternoon the best chance of thunderstorms will be KFLO/KLBT. Have
indicated VCTS but confidence is low. There is higher confidence
of showers/VCTS at KFLO/KLBT in the evening.
EXTENDED OUTLOOK...Scattered SHRA/TSRA through Thursday. A cold
frontal passage late Wednesday into Thursday. Primarily VFR
expected Friday through Sunday.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 1000 AM Wednesday...Stalled front will remain NW of the waters
today, with a weak pressure gradient persisting. Winds currently
around 5 kts will become SE at 5-10 kts, and may increase further to
10-15 kts late tonight with continued veering to the SW. This will
create seas of 2-3 ft through the near term, with a Southerly wind
wave and low amplitude SE swell comprising the spectrum. Showers
with isolated tstms will be possible across the waters late tonight
as well.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 345 AM Wednesday...Sfc pressure pattern and a tightening-
some of the gradient, will result in SW winds at 10 to around 15
kt thru this period. Significant seas will run 2 to 3 feet with 4
footers possible Wed and Thu when winds will be closer to 15 kt
sustained due to the semi-tightened sfc pg. Wavewatch3 and local
Swan keeps the ESE 11 second period ground swell affecting the
local waters but with some degradation. Local wind driven waves at
4 to 6 seconds will become the more dominant feature of the
significant seas by late Thu thru Friday.
The sfc cold front will finally push to the Carolina coasts
during Friday, and stalling just offshore the ILM Waters Friday
night. The dry slot or tongue will push across the waters late
Friday ending the threat for showers and thunderstorms.
LONG TERM/SATURDAY THROUGH SUNDAY/...
As of 3 AM Tuesday...A weakening cold front running parallel to
the coast will only slightly shift through the period moving from
just onshore to just offshore. It`s parent surface cyclone will be
well occluded and thus deprived of its energy source and so the
whole system will feature a baggy and poorly defined pressure
pattern. This is good news for most mariners though as winds will
be quite light and somewhat variable through the period. Seas will
be slightly elevated above what such slack winds would otherwise
support since spectral wave bulletins show a myriad of wave
elements.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.
&&
$$
SYNOPSIS...MBB
NEAR TERM...JDW
SHORT TERM...DCH
LONG TERM...MBB
AVIATION...MRR
MARINE...
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
650 AM CDT WED SEP 28 2016
.SHORT TERM... (Through Late Tonight)
Issued at 311 AM CDT Wed Sep 28 2016
Cold front is getting ready to enter the northern CWA, and will push
rapidly across the CWA by mid morning per the RAP. Regional radars
are showing that the scattered showers are currently staying close
to an upper low over northern Illinois. May still be a slight
chance of showers early across the Illinois counties as the cold
front moves through the area as the RAP is showing some weak mid
level ascent and low level convergence along the front. HRRR
reflectivity is showing some weak returns over south central
Illinois along the front. Highs today will be much cooler with cold
air advection behind the front. Went with a compromise of MOS highs
which is supported by the SREF ensemble temperatures.
Expect mainly dry weather tonight with some clouds lingering over
Illinois in close proximity to the upper low which will be moving
south across Indiana. Expect lows tonight to fall to close to the
agreeable MOS lows.
Carney
.LONG TERM... (Thursday through Tuesday)
Issued at 311 AM CDT Wed Sep 28 2016
Guidance has been consistently moving the upper low a bit
further west for the past several runs. It should be near the
Indiana/Kentucky border Thursday morning and it will spin over the
Ohio Valley at least through Saturday. The low starts lifting out on
Saturday night according to medium range guidance and should be
swallowed up into the longwave pattern over New England and
southeast Canada by Monday evening. For the Mid-Mississippi Valley
this means north-northwest flow through the depth of the troposphere
through Saturday. 850mb temps hover in the 7-10C range through
Sunday which mixes down to upper 60s to mid 70s each day.
Guidance is spitting out some light QPF primarily during the
afternoon and evening for Thursday through Saturday mostly along and
east of the Mississippi River. This looks reasonable given the
strength of the low and the multiple lobes of vorticity which rotate
around it through the weekend. Additionally, isentropic fields show
a nice feed of moisture on the cool conveyor belt off the Atlantic
with c-defs less than 10mb on the 295K and 300K isentropic surfaces
feeding back into the Mississippi Valley. Since models are in good
agreement now with this QPF and the aforementioned moisture feed,
will go ahead and bump up PoPs across parts of eastern Missouri and
Illinois for Thursday through Saturday. Will keep Sunday dry for
now with the low moving off and removing the moisture feed from the
east. Am continuing to lean heavily on cool MOS numbers and 850mb
mix down temperatures for highs through Saturday rather than
standard blended guidance due to more extensive cloud cover and
probable showery precip. Should see fewer clouds Sunday with an
upper ridge building overhead...and then return flow Monday and
Tuesday with temperatures rising back above normal.
Carney
&&
.AVIATION... (For the 12z TAFs through 12z Thursday Morning)
Issued at 649 AM CDT Wed Sep 28 2016
Expect mainly dry and VFR conditions at the terminals through this
evening. There may be some isolated showers over Illinois this
morning that will pass east of the TAF sites, but confidence is
too low to put them in any of the St. Louis metro terminals.
Winds will be mainly northerly behind a early morning cold frontal
passage.
SPECIFICS FOR KSTL: A cold front will move through the area early
in the period causing winds to turn out of the north. Mainly dry
and VFR conditions are expected through late tonight. Then MVFR
ceilings are expected to move into the terminal from the east
after 12Z on Thursday.
Britt
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Caribou ME
345 PM EDT Wed Sep 28 2016
.SYNOPSIS...
High pressure ridge will remain across the region into Saturday.
Low pressure will gradually approach from the south on Sunday.
&&
.NEAR TERM /THROUGH THURSDAY/...
The main challenges are cloud cover and fog potential tonight.
The latest visible satellite imagery showed clouds across northern
and coastal areas while the central portion of the CWA was seeing
sunshine. Temps varied where there was cloud cover as northern and
western areas were in the low to mid 50s north of Houlton and
Millinocket as they were running near 60. Central and interior
downeast areas were in the low to mid 60s. NNE were holding at 5
to 10 mph.
The latest GFS/NAM soundings including the HRRR showed clouds
breaking up for a time this evening across the north and west but
then returning after midnight w/the llvl moisture trapped below 2k
ft. This anticipated cloudiness can be seen residing back across
northern New Brunswick. Before this takes place, temps will fall
back for a time into the upper 30s. further to the e, the clouds
will keep temps up to around 40. Across the central and downeast
areas, mid 40s look good attm. The nne wind around 5-7 mph should
allow for the blyr to mixed some especially in the open areas.
Confidence is high enough that fog will form by early Thursday
morning. Valley and low lying locations have a chance of seeing
the fog w/the llvl moisture in place. The BUFKIT soundings point
to this as well.
High pres anchoring itself in across southern Canada will allow
for some sunshine on Thursday after some clouds and valley fog
erode by mid morning. Winds are forecast to more from the ne which
will add a chill to the air. Decided to boost Thursday afternoon
temps up from previous forecast based on how warm the central and
downeast region got(mid 60s). Northern and western areas are
expected to be in the upper 50s.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
The models are in good agreement through the period. A low
pressure system over central Kentucky with an occluded front
extending east into the North Atlantic along the coast of New
Jersey where it meets the warm and cold fronts and a high pressure
ridge across Northern New England and Eastern Canada will be the
major weather features to affect the weather through the period.
The high pressure ridge will remain in place across Maine through
the period as the warm front pushes north along the coast of
Southern New England with the front progressing to the Cape Cod by
the end of the period.
Loaded a blend of the GFS/GEM/NAM/ECMWF to smooth out the minor
differences in the models. Loaded NAWAVE4 for seas in the coastal
waters. Loaded windgust by factor tool. For QPF used RFCQFP for
first 12 hrs and a GFS for the rest.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A low over Michigan, with an occluded front extending to Cape Cod,
a warm front extended east from Cape Cod into the north Atlantic,
and a high pressure ridge will be the main weather features for
the start of the long term period. The parent low is showing signs
that it is becoming mature. The ridge of higher pressure will hold
across northern Maine as the warm front pushes into the Northern
Gulf of Maine waters and Southwest Maine. Saturday afternoon the
Occluded front moves into Southwest Maine, the warm front moves to
Mid-Coast. By Saturday evening the occluded front moves to central
Maine, the warm front affects the entire Gulf of Maine. Sunday
morning, a secondary low forms in the Gulf of Maine, the occluded
front moves to central Maine. The parent low is co-located with
the upper level low. Sunday evening Parent low begins to fill as
the new low in the Gulf of Maine, moves east to the south coast of
central Nova Scotia. Monday morning the parent low continues to
fill and drift east over Lake Erie. Maine will remain in wrap
around precipitation associated with the remnants of the occluded
low. Monday evening an upper level troph is expected to move
through absorbing the remaining energy from the filling upper
level low and moving to the Downeast coast. Early Tuesday morning
high pressure will once again ridge into the area, and will remain
through the end of the period. A deep low is forecasted to be
moving up the coast at the starting Monday evening and is
forecasted east of the coast of North Carolina by the end of the
period.
Loaded a blend to smooth out the minor differences in the models.
Loaded NAWAVE4 for seas in the coastal waters. Loaded windgust by
factor tool.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
NEAR TERM: VFR into tonight but conditions are expected to
deteriorate to MVFR and possibly IFR for all terminals for mainly
cigs but fog is a concern especially for KBGR, KHUL and KPQI based
on location near rivers and stream. A return to VFR for all
terminals by mid morning Thursday.
SHORT TERM: Aviation VFR conditions all sites through the period.
Early morning Fog around water bodies may lead to some vsby issues
for PQI, BGR, and BHB, conditions will improve rapidly after
sunrise.
&&
.MARINE...
NEAR TERM: SCA remains up through Thursday afternoon. Winds have
been coming up slowly, but seas are slow to come up as they are
still residing at 5 ft. Backed this up by a few hrs and show seas
building to around 6 ft in the outer zones by tonight. Winds will
increase to around 25 kts into early Thursday.
SHORT TERM: Winds and seas will be below SCA criteria through the
period. Seas around 5 ft with wind gusts to around 22 kts at the
start of the period will subside early in the period.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory until 5 PM EDT Thursday for ANZ050-051.
&&
$$
Near Term...Hewitt
Short Term...Norton
Long Term...Norton
Aviation...Hewitt/Norton
Marine...Hewitt/Norton
Area Forecast Discussion
National Weather Service Duluth MN
320 PM CDT WED SEP 28 2016
.SHORT TERM...(This evening through Thursday)
Issued at 300 PM CDT Wed Sep 28 2016
Wrap around cool mid level temperatures and moisture has kept low
clouds over the forecast area today. Afternoon temperatures
struggled to reach to the upper 50s to low 60s for most areas
today. The instability and northeast flow also produced light
rain/sprinkles over northern wisconsin today.
As the area of low pressure currently residing near Chicago
continues to slowly sink southward through thursday, it will
allow for a ridge axis to slide east into the western Lake
Superior region. This ridging will bring more sun and warmer
temperatures into Thursday. However, have increased cloud cover
tomorrow as latest BUFR soundings show lingering low level
moisture around 3kft trapped under the mid level subsidence
inversion.
.LONG TERM...(Thursday night through Wednesday)
Issued at 300 PM CDT Wed Sep 28 2016
Summary: A large area of low pressure over Kentucky will
retrograde or lift north to mainland Michigan by Saturday night
and move through New England or the Mid-Atlantic early next week.
The dominating nature of this low will maintain a few days of
light easterly flow and daily similar weather across the
Northland, Friday through Sunday. Temperatures will likely be
about 5 to 10 degrees above seasonal normals through the period.
The next best chance for precipitation will likely be towards the
middle of next week.
A large, vertically-stacked and cut-off area of low pressure will
be over Kentucky as of Thursday evening. The low will retrograde
or lift north through the rest of the week, reaching mainland
Michigan by Saturday night, then move through New England or the
Mid-Atlantic through early next week. The low will act to block
any significant movement in a ridge of surface high pressure
stretching from northern Ontario, through northern and western
Minnesota, to the Central Plains. Therefore, the Northland can
expect a few days of light easterly flow and relatively similar
weather, Friday through Sunday. While northeast Minnesota should
have daily mostly clear skies, save for some midday inland (from
Lake Superior) scattered cumulus, northwest Wisconsin will be a
bit cloudier due to its greater proximity to the area of low
pressure. There may even be some very light rain associated with
the low that may reach parts of northwest Wisconsin Saturday.
Daily highs will be in the lower to middle 60s, and lows in the
lower to middle 40s.
It may get even a bit warmer early next week. The departing low
will allow to finally shift east, and for low pressure to begin
moving east from the western US into the Plains. Breezy southeast
flow will develop across the Northland Monday and Tuesday ahead of
the approaching low pressure. The low pressure will bring the
Northland`s next best chance for any significant precipitation,
but the new model runs continue to delay when the precipitation
moves into the Northland from the west. It now looks like the rain
will hold off until at least late Monday night or Tuesday, but
possibly as late as Wednesday. Kept a slight chance of thunder
given the degree of warmth in the southerly flow aloft, the
relatively strong 40 to 50 knot low-level jet, and strength of the
cold front.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1239 PM CDT Wed Sep 28 2016
The cool north-northeast flow across northeast Minnesota and
northwest Wisconsin will continue into tonight, while a high
pressure will slowly move into the region from the northwest. The
cool flow has helped develop widespread broken/overcast MVFR
cumulus ceilings across the Northland today, with conditions
further becoming cloudier than earlier forecasts. The HRRR and
4-km NAM have been doing really well in depicting the widespread
low-level cloud cover, where most other models have been much
clearer. The HRRR and 4-km NAM continue to maintain this cloud
cover through at least Wednesday, despite the high pressure
nudging into the region tonight and Wednesday. I trended the
aviation forecasts cloudier, adding longer periods of MVFR
ceilings today into tonight. May need to keep the MVFR even
longer, but there is still a bit of chance of enough scattering
of the cloud cover before sunset. Whatever cloud cover remains by
sunset will have a difficult time dissipating overnight.
Since it looks like tonight will be cloudier than earlier
forecast, the threat of fog developing later tonight does not
appear to be as much as before. However, wherever there are
pockets within the cloud cover overnight, fog could develop.
Therefore, kept some lower IFR/MVFR visibility later tonight to
suggest the possible fog.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 45 61 46 64 / 0 0 0 0
INL 41 61 42 67 / 10 0 0 0
BRD 42 64 43 68 / 0 0 0 0
HYR 45 63 43 68 / 10 0 0 0
ASX 48 60 46 63 / 10 10 0 0
&&
.DLH Watches/Warnings/Advisories...
WI...Beach Hazards Statement until 8 PM CDT this evening for WIZ001.
MN...Beach Hazards Statement until 8 PM CDT this evening for MNZ037.
LS...Small Craft Advisory until 4 PM CDT this afternoon for
LSZ140>147.
Small Craft Advisory until 10 PM CDT this evening for LSZ121-148.
&&
$$
SHORT TERM...Graning
LONG TERM/AVIATION...Grochocinski
Area Forecast Discussion
National Weather Service Quad Cities IA IL
342 PM CDT WED SEP 28 2016
.SYNOPSIS...
Issued at 340 PM CDT Wed Sep 28 2016
Vertically stacked upper low seen on satellite movie loops
spinning over northern Indiana was spreading stratocumulus/stratus
as far west as the Dakotas/MN border and far western IA. Under
this canopy of clouds temperatures in the dvn cwa were rather
cool, in the upper 50s to lower 60s. Scattered showers were
located in southern WI and northern IL and were moving southwest.
&&
.SHORT TERM...(This Evening through Thursday)
ISSUED AT 340 PM CDT Wed Sep 28 2016
Forecast focus on cloud trends and temperatures.
Tonight: Any scattered showers or sprinkles should end by 7 pm
according to the HRRR with much of the night dry. Satellite loops
indicated clearing taking place in eastern WI as drier air rotates
around the upper low. We will be going with the idea this clearing
trend will spread southwest into the dvn cwa overnight. Therefore,
skies should eventually become clear or partly cloudy at most
locations. The center of the low should push southward into
southern Indiana by sunrise with high pressure ridge extending
from northern MN to the TX panhandle. Minimum temperatures will
range from the mid 40s to the lower 50s.
Thursday: Models suggest the synoptic pattern to become locked in
place with the closed upper low becoming stalled in far southern
IN or western KY, with the surface ridge from MN to TX. Most of
the cwa will enjoy sunshine especially west of the MS River closer
to the ridge. However, northeast winds coming off Lake MI due to
the cyclonic circulation around the low should spread low clouds
back into our eastern cwa. There may also be a small chance of
showers or sprinkles in our far eastern counties. Temperatures
should be warmer with highs around 70 at most locations.
.LONG TERM...(Thursday Night through Wednesday)
ISSUED AT 340 PM CDT Wed Sep 28 2016
Thursday Night...Vorticity maxima begin to pinwheel around Ohio
Valley upper-low, making westward progression back into E Iowa/
NW Illinois/and NE Missouri. Sensible weather effects will be
limited. We`ll have increasing low clouds, and a slight chance for
light showers across the far east - primarily in Bureau and Putnam
Counties.
Friday and Saturday...Models have converged on low retrograding
further NW. Went cooler for max temps, below the SuperBlend, to
account for reduced solar insolation from low stratus. Mid to upper
60s are the current going forecast but further downward adjustments
remain possible. Winds are forecast to be strongest on Friday,
between 10-20 mph (isolated higher gusts) out of the NNE.
Precipitation: Isolated to scattered showers are likely at times.
The highest PoPs are over the eastern half of the CWA and peak
between 40-50% Friday afternoon through Saturday. Further west,
chances are lower and many locations may receive little to no
measurable rain.
Sunday and Monday...Model suite in reasonable agreement weakening
the upper-level low on Sunday and tracking it to the NE through
Michigan. This will be a dry stretch of weather with temps in the
70s.
Tuesday and Wednesday...Pattern transitions into a warmer, return
flow scenario. Dewpoints may rise into the 50s; however, the best
moisture advection will probably occur on Wednesday as it pools
along a cold front. May need to remove shower chances over the
west in future updates because forcing and low-level convergence
are negligible. Wednesday...showers and thunderstorms may
accompany the front but it is too early to assess the severe
potential and coverage of storms. ..Uttech..
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
ISSUED AT 340 PM CDT Wed Sep 28 2016
VFR conds through this taf cycle. North winds 10 to 20 knots this
afternoon then around 10 knots tonight into Thursday morning.
&&
.HYDROLOGY...
Issued at 100 PM CDT Wed Sep 28 2016
Overview: Most significant change was at New Boston on the
Mississippi River where the crest forecast increased from moderate
to major flood stage. Otherwise, river forecasts are largely on
track. See site specific information in the following discussion and
in recent Flood Warning Statements.
Cedar River...
Vinton: Now below major flood stage.
Cedar Rapids: Forecast to fall below major flood stage Thursday
evening or night.
Conesville: Major flooding is occurring as river level rises
rapidly. Timing of crest forecast is Thursday afternoon into
Thursday night. Confidence is moderate to high on a crest a half
foot on either side of 18.30 feet.
Wapsipinicon River...
Anamosa Shaw Rd: Forecast to fall below major flood stage this
evening.
De Witt 4S: High confidence in reaching major flood stage. Thinking
current crest forecast is on the upper end of possible outcomes.
Reasonably high probability the final crest is lower. Please
monitor for updates.
Iowa River...
Excessive amounts of water continue to propagate downstream through
the Iowa and Cedar Rivers. There is high confidence on significant
flooding. Exact timing varies by site.
Moderate confidence is associated with the crest forecasts. Current
thinking is crest forecasts are toward the upper range of what is
possible; observed crests may come in lower. Please follow forecast
information closely throughout this event.
Mississippi River...
Minor to Major flooding continues to be on track. Greatest forecast
change was at New Boston with an increased crest forecast from
moderate to major. Otherwise, latest forecasts show little to no
adjustments. Majority of the crests are projected to occur over the
weekend or early next week. Uttech
&&
.DVN Watches/Warnings/Advisories...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...Haase
SHORT TERM...Haase
LONG TERM...Uttech
AVIATION...Haase
HYDROLOGY...Uttech
Area Forecast Discussion
National Weather Service Wilmington NC
635 PM EDT Wed Sep 28 2016
.SYNOPSIS...
A cold front approaching from the west will slow down on Friday and
linger near or along the Carolina coast through this weekend. High
pressure will build in behind the front through early next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 300 PM Wednesday...Convection has broken out along the
piedmont as expected, with a few showers/storms along the sea breeze
as well. A few of these storms have the potential to become strong,
especially far NW zones and just outside of the CWA, where
thermodynamics and forcing mechanisms best overlap. These include
height falls ahead of the deepening upper low, increasing low-level
winds around 850mb, SBCape of 3000 J/kg, and 0-6 km bulk shear
around 20 kts. Latest HRRR and 12z NSSL WRF are both modeling the
current situation pretty well, and expect most of the activity to
remain just outside the CWA border to the west, with the best chance
for any severe storms remaining well NW of the ILM CWA. That being
said, cannot rule out an isolated strong wind gust along i-95 this
aftn/eve, before diurnal heating wanes and storms weaken and
dissipate.
Tonight, a second round of convection is possible as a vorticity
lobe streaks up from the south, embedded in the mean flow between
the Atlantic Ridge and deep closed low to the west. Elevated
instability will remain, and forcing within this vort will be enough
to cause more showers with isolated tstms tonight, and this may
affect a larger portion of the CWA than will be impacted through
this eve. Do not expect strong or severe overnight, but more showers
will be possible and have continued CHC Pop through the overnight.
Temperatures overnight will remain above seasonable norms, with mins
dropping only to around 70.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 300 PM Wednesday...Synoptic pattern changes very little
through the end of the week, although sensible weather will improve
through the period. Deep upper low across the OH VLY will remain the
dominant feature as flow becomes very slow, keeping the closed low
basically stationary through the period. This will cause a cold
front to move slowly to the east, but guidance has backed off even
further on this motion, and it is now progged to not quite make it
to the coast even by Friday night. This will keep unsettled weather
with warmer temperatures across at least the eastern third of the
CWA, while locations out towards i-95 should still break into the
drier and cooler air, especially on Friday. This is noted by much
lower RH above 850mb advecting eastward in a dry slot beneath the
upper low. However, the large ridge across the Atlantic remains
strong, and forces the moist air ahead of the front and the dry slow
to remain along the coast, while the pinched flow between these
features drives vort impulses and shower chances northward into the
region. Friday will overall be a drier and slightly cooler day than
Thursday, that will be most felt well inland, while the immediate
coast may see little change with above climo temps and scattered
aftn convection.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 300 PM Tuesday...Latest model run keeps deep cutoff upper
low a bit farther west as it tracks up toward the Great Lakes over
the weekend. Therefore the sfc front and deeper moisture should remain
aligned parallel, just along the coast rather than off shore.
Plenty of dry air will wrap around the upper low into the
Carolinas aloft, but the lower dewpoint air behind the sfc
boundary may struggle to make it to the coast. Also, the sfc
boundary will remain a focal point for convective development and
although the air aloft will be drier, there should still be
shallow convection possible along and east of the boundary. There
will be a sharp gradient between the drier air to the west and
moister air to the east, but exactly where that will lie is tough
to say. The models are trending on keeping the boundary farther
west, along the coast, rather than off shore. This will mean more
clouds, showers and more humid air in place over the eastern half
or third of our area, but as you move inland there will be greater
amounts of sunshine and drier air. The latest pcp water shows
values up close to 2 inches from the tip of Cape Fear up to
Hatteras while west of I-95 will have PWATS less than an inch with
even lower amounts as you head W-SW. Essentially, the drier air
will wrap around from the SW aloft and N-NW at the sfc and it will
be more of a dewpoint gradient rather than temps. Daytime highs
will remain in the 80s most places. The guidance has backed off on
the cooler overnight lows due to the lack of lower dewpoint air
moving in, but I still think many places inland will get down
toward 60 early Sat.
As the the mid to upper low lifts north Sunday through early next
week, the lingering boundary will be pulled farther back on shore
as it dissipates through Monday. The winds should shift around to
the NE to E bringing some moister air back inland. Overall, places
inland and west of surface boundary will see a greater amount of
sunshine while places east of boundary will see a greater amount
of clouds and chc of pcp.
Heading into the middle of next week, the forecast become further
complicated by the differences in the models as to the track and
timing of Tropical Cyclone Mathew. For now, this system looks like
it will track westward and eventually turn up around the Atlantic
Ridge. The GFS is much faster with this system and we will have to
see how this evolves to determine how or if this affects the
southeast coast. For now, the greatest effects may be over the
coastal waters in pulses of swells and increasing gradient winds
eventually drive up the seas.
&&
.AVIATION /00Z THURSDAY THROUGH SUNDAY/...
As of 00Z...A frontal boundary will continue remain nearly
stationary over the western portion of the region. Much of the
convection will start to wind down, however the HRRR model has been
fairly consistent with overnight convection nearly in the same place
as the convection currently ongoing. It may be a reflection of what
is leftover from the sea breeze boundary. Some of this convection
will try to make it to the coast, but will weaken as it does so.
Thursday, some scattered convection possible by mid to late
afternoon, still associated with a weak frontal boundary and an
upper low well west of the region.
EXTENDED OUTLOOK...Primarily VFR. Isolated to scattered afternoon
showers through much the period, although limited in strength and
coverage due to dry air aloft.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 300 PM Wednesday...Stalled front continues to sit NW of the
waters, with a weak pressure gradient remaining in place. Winds will
slowly veer from present S/SE to SW overnight, along with a slight
increase in speed from 5-10 kts to a more uniform 10 kts. This will
create seas of 2-3 ft, with a southerly wind wave and low amplitude
SE swell comprising the spectrum. Showers with isolated tstms will
be possible across the waters late tonight as well.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 300 PM Wednesday...Slow moving cold front will drag west to
east through the short term, finally approaching or stalling across
the waters Friday night. This will keep the waters in the warm
sector with S/SW winds of 10-15 kts expected through most of the
period, possibly shifting to the W/NW Friday night. These persistent
winds combined with the offshore high pressure will keep a 5-6 sec
southerly wind wave and 9-10 sec SE swell in the spectrum, creating
2-3 ft seas.
LONG TERM/SATURDAY THROUGH MONDAY/...
As of 300 PM Tuesday...A cold front will run parallel along or
near the Carolina coast...weakening through early next week.
Overall expect more northerly winds on west side of front to come
around to the NE to E as weakening boundary gets drawn back westward
as upper low lifts off to the north through the period, but great
variability is possible. Southerly winds should continue to the east
of the boundary. Seas will generally remain 2 to 3 ft over most
waters but a slight rise will be seen due to some longer period SE
swells mixing in through the weekend into early next week.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.
&&
$$
NEAR TERM...JDW
SHORT TERM...JDW
LONG TERM...RGZ
AVIATION...43
AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
124 PM PDT WED SEP 28 2016
.SYNOPSIS...
Temperatures will continue to gradually cool through the weekend.
There is a slight chance of afternoon showers and thunderstorms
today in the Los Angeles and Ventura County mountains and adjacent
valleys.
&&
.SHORT TERM...(TDY-SAT)
For today focusing on the potential for afternoon convection over
the LA/Ventura county interior. So far not seeing much vertical
development but still plenty of heating to go and what appears to
be some additional energy coming in from the northeast. The HRRR
model shows very little activity through 5 pm, then some showers
and possible storms in the early evening, mainly across the nrn
Ventura county mountains and the Antelope Valley. Precipitable
water not too high, generally around an inch, so the main concern
is for brief heavy rain, small hail, gusty winds, and lightning.
Probably not a big flood threat as northeast steering winds
should keep any storms moving.
Gradients will continue to trend onshore into the weekend as
a trough approaches from the northwest. There may be one more day
of some afternoon cu over the mtns but moisture and instability is
less than today so for now am going to keep storms out of the
forecast. Marine lyr coverage expected to be very similar as last
night, mainly just Central Coast. In fact, don`t see any solid
marine lyr south of Pt Conception until Saturday morning at the
earliest. Temps will continue their decline, though a little more
gradual now, mostly 2-4 degrees per day, until we are back to near
normal readings by around Friday and possibly even slightly below
normal Saturday.
The main impact from the upcoming trough besides the cooler temps
will be increasing northwest winds along the Central Coast, srn SB
County, the I5 corridor region, and Antelope Valley. Likely advisory
level winds at times, especially by Saturday afternoon and
evening.
.LONG TERM...(SUN-WED)
The trough that moves through Friday night into Saturday will be
the first of several that will mostly impact northern California.
There are a couple of weak cold fronts that will mostly wash out
before reaching SLO county, the first one late Sunday and then
another late Monday. Models aren`t fully in agreement but none of
them show any of these troughs holding together well enough to
generate any rain, even for the Central Coast. So will maintain a
dry forecast for now. Main impacts initially will be the cooler
temps and persistent northwest flow that will continue to generate
advisory level winds at times in the usual areas. As we get into
the middle and end of the week high pressure aloft will build into
California from the west while a surface high builds over the
Great Basin. While the air mass warm up gradients will be shifting
to offshore and we may be looking at another Santa Ana event by
Thu/Fri.
&&
.AVIATION...28/1800Z.
At 1648Z...the weakest of marine inversions was noted, based at
1100 feet at KLAX. The top of this very weak inversion was at 1900
feet with a temperature of 24 C.
Good confidence in the 18z TAFS. A weak inversion has formed at
KLAX, however weak offshore flow and mid level cloudiness is
likely to prevent marine clouds from forming overnight. Marine
clouds are expected to form along portions of the central coast.
Although there is no mention of a slight chance of thunderstorms
in the Antelope Valley and San Fernando Valley TAFS, an isolated
storm cannot be ruled out during the afternoon hours.
KLAX...Good confidence in the 18Z TAF with VFR conditions
expected thru tonight. There is a 20 percent chance of marine
clouds with IFR conditions sneaking into the airfield early
Thursday morning.
KBUR...High confidence in the 18Z TAF with VFR conditions
expected thru the period. There is a 20 percent chance of a
thunderstorm in the vicinity of the airport between 22z and 03z.
&&
.MARINE...28/200 PM...
Mostly light winds are expected across the coastal waters through
Thu with SCA conds not expected. Northwest winds are expected to
increase across the outer waters and northern inner waters
late Thu through Fri, with SCA conditions likely in those areas
Fri evening through at least Sun. There is a 50 percent chance
that SCA conds will spread into the SBA Channel and the southern
inner waters by Sat afternoon continuing through Sun.
There is a 20 percent chance of Gale Warning conditions sometime
this weekend mainly across the outer waters from Point Conception
to San Nicolas Island.
Extra surging and currents are possible near the coast due to a
long period south swell of 2 to possibly 4 feet by Thursday
morning, peaking late in the day into Friday before subsiding this
weekend.
Locally dense fog is possible across much of the coastal waters
tonight through Thursday morning.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&
$$
PUBLIC...MW
AVIATION...Sweet
MARINE...Sweet
SYNOPSIS...KJ
weather.gov/losangeles
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
225 PM EDT Wed Sep 28 2016
.SYNOPSIS...
An upper level low will impact the area through Thursday night...
bringing the potential for heavy rainfall to the Mid Atlantic.
This will gradually move away from the area this weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
Complex weather situation is unfolding across the area...as
strong upper-level low is dropping southward into the Ohio River
Valley. At the surface, frontal boundary is across southern
VA...remaining nearly stationary. Very challenging forecast over
the next couple of days. It`s interesting to see how much the
atmosphere moistened up in the 12 hours today between the 00Z and
12Z IAD sounding.
Training storms could lead to some flooding issues later today.
For hours the HRRR has been projecting a band of rain setting up
from south to north this evening over the I-95 corridor. Given the
atmosphere has been outputting heavy rainfall already in this air
mass believe that if this line does indeed develop that 1-2"/
locally more could be possible overnight.
Another factor with the sounding/VWP is the wind field - low level
winds are from the east...turning abruptly to the southwest above
6000 feet. Turning in the atmosphere has led SPC to put the CWA
east of the Blue Ridge at a 5% tornado risk. Limiting factor would
be extensive cloud cover. If a tornado were to impact our CWA it
would likely develop in SE VA and track north.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Thursday is a day for all to be concerned about. BUFKIT soundings
are showing a strong low level easterly flow. This is a prime
heavy rain/flood producer. It is difficult to pick an exact spot
where the heaviest rain could fall but two areas of conern appear
to be 1) the area between DC and the PA border and 2) the eastern
slopes of the Blue Ridge. Flash flood watch is in effect through
Friday morning for the CWA with the exception of the Highlands.
Depending upon rainfall rates and fact that ground has been dry
this month we may see steadier rises on streams/creeks...and over
time see main stem rivers rise.
To summarize - high concern for possible flooding Thursay but it
is too early to pinpoint where.
Despite the weak instability on Thursday...strong wind field
remains... so there could be a few stronger storms with wind/hail
threats.
The concern will definitely continue Thursday night as the upper
cutoff low continues to spin to our west. East/southeast flow will
keep the moisture streaming into the northern Mid Atlantic.
Flooding threat will persist.
Showers will also be possible through Friday. The thought process
will continue to evolve with later forecasts.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Upper low will remain across the Ohio Valley this weekend. Hence, we
will need to keep a chance of showers in the forecast for at least
Saturday. However, that chance will be less than the end of the week
as the low will begin to lift toward the Great Lakes and eventually
the St. Lawrence Valley. That should permit a drying trend, making
Sunday the better of the two weekend days.
High temperatures will be near normal for the start of October.
Lows, on the other hand, will be about 5 to 10 degrees above normal,
due to the humidity from the influx of moisture.
High pressure should be back for early next week.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Upper-level low will impact the area today through Friday...bringing
IFR/LIFR to all the terminals. Heaviest rain expected late
tonight into Friday. Isolated thunderstorms are also possible this
afternoon and Thursday afternoon. Could see a gradual return to
VFR later Friday afternoon.
Gradual improvement through the weekend. VFR should generally
prevail by Sunday.
&&
.MARINE...
SCA in effect for the lower half of the Chesapeake Bay and lower
Tidal Potomac...and for all waters starting later this evening
through 12z Friday...as gradient winds increase with strengthening
system. Gradient should begin to relax by later Friday...with SCA
winds less likely.
Upper low will slowly lift and fill this weekend. No flags
anticipated at this time.
&&
.TIDES/COASTAL FLOODING...
Current forecast keeps tidal sites below flood stage at least
through most of Thursday. This will be monitored to see if
coastal flooding concerns arise sooner.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Flash Flood Watch from 6 PM EDT this evening through Friday
morning for DCZ001.
MD...Flash Flood Watch from 6 PM EDT this evening through Friday
morning for MDZ003>006-011-013-014-016>018-502>508.
VA...Flash Flood Watch from 6 PM EDT this evening through Friday
morning for VAZ025>031-036>040-050>057-501-502-505>508.
WV...Flash Flood Watch from 6 PM EDT this evening through Friday
morning for WVZ050>053-055-504.
MARINE...Small Craft Advisory from 6 PM this evening to 8 AM EDT Friday
for ANZ530>532-535-536-538>541.
Small Craft Advisory until 8 AM EDT Friday for ANZ533-534-537-
542-543.
&&
$$
PRODUCTS...WOODY!
Area Forecast Discussion
National Weather Service Marquette MI
416 PM EDT Wed Sep 28 2016
.SHORT TERM...(This evening through Thursday)
Issued at 415 PM EDT WED SEP 28 2016
WV imagery and RAP analysis indicated a mid/upper level low over nrn
Indiana and a ridge from the wrn plains into nrn Ontario. At the
surface ne winds prevailed between a ridge into nw Ontario and the
low over IN. Although the deeper moisture had departed, radar showed
isold/sct -shra over the n and w portions of the cwa as 850 mb temps
around 5C,,daytime heating, and cyclonic flow with low level
moisture supported the light pcpn.
Tonight, expect that abundant moisture below 850 mb, and 850 mb
temps remaining around 5C (water temps from 11C-15C) will be enough
to sustain some isold -shra into the north and west, downwind from
ene to ne flow off the lake, mainly over the Huron Mountains and
from IWD to Ontonagon. Otherwise, temps will drop into the mid and
upper 40s inland and around low to mid 50s near the Great Lakes.
Thursday, mostly sunny skies over the east half and decreasing
clouds over the west as the sfc ridge builds into the area will
allow temps to climb into the mid 60s west and to near 70 south and
east.
.LONG TERM...(Thursday night through Wednesday)
Issued at 325 PM EDT WED SEP 28 2016
Dry wx accompanying sfc hi pres wl dominate the the beginning of the
medium range period. But as the closed lo pres responsible for the
recent pcpn lifts fm the OH River Valley back over Lower MI btwn a
deepening wrn trof and a bldg rdg off the e coast, some showers may
return as early as Sat and linger thru the weekend, especially over
se Upr MI. Any weekend showers wl give way to dry wx early next week
as another hi pres rdg dominates under a bldg upr rdg to the e of
the slow moving wrn trof. Although Thu ngt could be chilly
especially over the interior w under the initial hi pres rdg, above
normal temps should dominate the medium/extended range period.
Thu ngt...Sfc hi pres rdg axis stretching fm near James Bay into the
Upr Lks and area of mid lvl dry air to the n of nearly stnry closed
lo in the OH River Valley wl bring tranquil wx to Upr MI. Expect the
lowest min temps that may dip into the 30s at the interior cold
spots over the w under axis of lowest pwat arnd 0.5 inch/light
winds. Tended aob the lo end of guidance in this area for the lo
temps. A steadier e wind under the tighter pres gradient btwn the hi
pres rdg and the lo pres to the s as well as perhaps some hi clds
closer to the closed lo wl limit the diurnal temp fall over the se,
especially near the warming influence of Lk MI.
Fri...The closed lo to the sse is progged to move slowly to the n.
Although the deep lyr forcing associated with this disturbance wl
remain to the se, expect some incrsg hi clds as h5 hgts fall slowly.
The area from Ironwood to the Keweenaw wl see the most unfiltered
sunshine. h85 temps fcst arnd 10C wl support max temps climbing at
least near 70 away fm the moderating influence of the lks in a slowly
incrsg ene wind.
Fri ngt into Sun...As an upr trof deepens over the w and an upr rdg
blds in the wrn Atlantic Ocean, the sly wind component btwn these
larger scale features is progged to lift the closed lo back nwd and
over Lower MI. The medium range guidance is in good agreement
showing incrsg mid lvl rh but hints the most sgnft deep lyr forcing
wl tend to remain to the ese of the cwa. Since the initially dry
llvls associated with the slowly retreating sfc hi pres rdg wl have
to be overcome, suspect pcpn wl have a hard time overspreading the
area, especially the nw. Plan to go with no more than chc pops, hiest
over the se cwa closer to the closed lo center. Although the clds wl
tend to hold max temps not too far fm normal, min temps on Fri ngt
and Sat ngt should run well above avg.
Sun ngt thru Wed...The closed lo is progged to exit to the e on Sun
ngt/Mon as an upr rdg blds over the Great Lks to the e of the
deepening Rockies trof. Any lingering pcpn should diminish late on
Sun as the closed lo/mid lvl mstr exit to the e and a sfc hi pres
rdg axis to the se of Hudson Bay hi pres blds over the wrn Great
Lks. Then expect dry wx on Mon into at least Wed as the sprawling
sfc hi center blds toward New England/the Cndn Maritimes. The incrsg
sly flow btwn this hi and falling mslp in the Plains ahead of the
deep wrn trof wl advect unseasonably warm air into the Upr Lks. h85
temps are progged to reach as hi as 10-12C by Tue. Showers ahead of
the sfc lo pres/cold fnt ahead of the slow moving wrn trof may
arrive by Wed.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 142 PM EDT WED SEP 28 2016
East to northeast winds north of departing low pressure system will
keep some showers going along with lower cigs across the area into
this afternoon. Cigs may be as low as LIFR at IWD before trending
MVFR. At CMX MVFR cigs will trend to lower VFR late this aftn.
Clouds may scatter out this evening at CMX and SAW but should stay
bkn-ovc at IWD. Overall looking at MVFR conditions tonight but could
even dip to IFR or lower at IWD. Although clouds should move out
late tonight, There is some uncertainty when the cigs will give way
to VFR at IWD Thursday morning. Otherwise, VFR conditions are
expected at CMX/SAW by late evening.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 415 PM EDT WED SEP 28 2016
Weakening low pressure will result in 15-25 kt winds late this
afternoon diminishing to less than 20 kts tonight. A general weak
pressure gradient lingering into the weekend should keep east to
northeast winds at 20 kts or less.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Beach Hazards Statement until 8 PM EDT this evening for MIZ005-
006.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...KC
AVIATION...JLB
MARINE...JLB
Area Forecast Discussion
National Weather Service Nashville TN
327 PM CDT WED SEP 28 2016
.DISCUSSION...
Cold front is clearly depicted on the latest sfc analysis. The
boundary stretches from just east of ckv southwest through the
waverly area. Scattered light shower activity is oriented along and
just behind the boundary. The upper trough axis is providing the
post frontal lift with some pva moving through the area. The
westward extent of the moisture does cut off just north of ckv.
Thus, will continue with the higher pops east theme for the fcst.
Latest HRRR in line with the southward moving band of showers. By
06z the activity will push east of the area. Will only include a
slight chance of showers aft midnight, some 30 pop prior.
Moving forward, the upper low will move very slowly southward
through tomorrow afternoon. On Friday it will start to lift slowly
northward. So, given the close proximity of the upper low and a
continuation of weak impulses on the back side, low shower chances
will persist for a good chunk of our area through Friday.
Examining the 850 mb moisture levels and the higher convective
daytime lapse rates, pops will be into the chance category across
the north and east for both Thursday and Friday afternoons. Still
looking at some isol t on Thursday afternoon as the closer proximity
of the upper low exists and showalter values drop.
For the near term temps, a cool period is in store. The clouds and
light shower activity will keep highs mostly in the 65 to 70 degree
range, and lows in the 50s. I am thinking about undercutting
guidance by several degrees tomorrow, particularly across
northern areas. The close proximity of the upper low may keep us
cooler.
In the ext fcst, upper low will lift out on Saturday and will be
replaced by upper ridging for Tues and Wed. This will equate to a
dry period with a warming trend. High temps will start out in the
low to mid 70s on Saturday, but will reach the mid 80s by Wednesday.
Lows in the 50s will warm into the lower 60s by Wednesday.
&&
.AVIATION...
18Z TAF DISCUSSION.
BNA/CKV/CSV...Cold front is bearing down on Middle Tennessee, with
FROPA taking place during the afternoon and evening. Only
scattered showers are expected with the front, and will handle
with VCSH remarks for now. Conditions should remain VFR until
late tonight and Thursday morning when MVFR cigs develop. Look
for gusty winds this afternoon as winds shift to the NW, then
diminishing during the evening.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 52 67 53 71 55 / 20 40 10 30 20
Clarksville 51 67 51 69 55 / 10 40 10 30 20
Crossville 51 61 48 66 51 / 30 40 20 30 20
Columbia 51 69 52 71 54 / 10 20 10 20 10
Lawrenceburg 51 69 52 71 54 / 20 20 10 20 10
Waverly 50 67 51 68 55 / 10 20 10 30 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......21
AVIATION........08
Area Forecast Discussion
National Weather Service Pueblo CO
240 PM MDT WED SEP 28 2016
.SHORT TERM...(This evening through Thursday)
Issued at 237 PM MDT Wed Sep 28 2016
The upper level ridge over the area will be shifting a little
eastward for tonight and Thursday, as an upper low over southern CA
weakens and moves over the Great Basin, and an upper trof approaches
the Pacific NW. The NAM and the GFS show the possibility of some
isold pcpn over portions of the Continental Divide this evening,
while the HRRR and NMM keep the area dry. Most low temps tonight at
the lower elevations will be in the 40s, with a few locations in the
30s.
On Thursday, there should be more moisture over the mountain and
high valleys areas, and therefore there will be a better chance for
showers and thunderstorms in the afternoon hours, especially over
the Continental Divide. The southeast plains and I-25 corridor are
expected to remain dry. With increasing sfc pressure gradient over
the sern plains, breezy southerly winds are expected in the
afternoon over that area. High temps on Thu wl again be a little
above average.
.LONG TERM...(Thursday night through Wednesday)
Issued at 237 PM MDT Wed Sep 28 2016
Models continue to be in good agreement through the weekend with
differences heading into next week. Ensembles have higher spreads
beginning Monday in regards to the pattern evolution, especially
with the strength and location of an upper trough.
Thursday night through Sunday...the upper level pattern will favor a
slow moving upper low over the Ohio Valley while high pressure is
centered over the central plains. An upper level storm system is
forecast to strengthen off the Pacific Northwest. This will force
flow southwesterly across Colorado with a modest moisture tap off
the Pacific and several weak disturbances moving north across
Colorado.
Expect to see showers and thunderstorms over the mountains Thursday
night and through the weekend. Snow levels will remain high, but a
couple inches of snowfall are possible along the continental divide
through Sunday. One weak disturbance is forecast to lift north
across Colorado on Friday, with the best chances for showers and
thunderstorms to move off the mountains and across the plains.
Models in line with a disturbance on Saturday as well, but lifts it
too far north to have much impact across southeastern Colorado. The
exception may be the Palmer Divide Saturday evening. More isolated
shower and thunderstorm activity is forecast on Sunday for the
mountains. Temperatures will remain warm across the lower
elevations with highs in the mid 70s to lower 80s and overnight lows
in the 50s.
Monday into Wednesday...the forecast depends on the evolution and
track of the Pacific Northwest storm system. The latest GFS and
ECMWF are in decent agreement with a much further and slower track
than yesterdays runs. The main forecast change for Monday would be
an elevated fire weather risk, as southwesterly flow increases and
mixing allows for enhanced drying, especially in the lee of the
eastern mountains. Showers and thunderstorms will likely move into
the continental divide Monday afternoon. A cold front is expected
by Tuesday with much cooler air working into the area. This will
drive snow levels down with a few inches possible above 8 kft. As
for the rest of the area, precipitation chances will all depend on
the storm track, available moisture and wind flows. Temperatures
will be cooler by 10 to 20 degrees Tuesday into Wednesday. Mozley
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 237 PM MDT Wed Sep 28 2016
VFR conditions are expected at the terminal forecast sites tonight
and Thursday. Some breezy south the southeast wind wl be possible in
the afternoon hours at KCOS and KPUB on Thu, with breezy south to
southwest winds late in the afternoon at KALS.
&&
.PUB Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...28
LONG TERM...MOZLEY
AVIATION...28
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
237 PM CDT WED SEP 28 2016
.SHORT TERM...(This evening through Thursday)
Issued at 236 PM CDT Wed Sep 28 2016
This afternoon, the prominent upper level low was located over
northern Illinois/Indiana and is expected to continue drifting south
through tomorrow. A back door front that moved across northeast
Kansas early this morning has aided in the cool temperatures today
as north northeasterly flow continues over the area. High
temperatures today have been lowered slightly with very northeast
Kansas topping out in the high 60s. Status located in Iowa has been
slowly moving south today, but it looks like the deck will stay east
of the area with only few to scattered clouds expected overnight.
Cooling overnight will bring lows into the mid and upper 40s.
Similar day tomorrow as today with dry conditions and cool
temperatures expected as the upper level ridge to the west begins to
move into western Kansas. Highs Thursday will be near 70 degrees.
.LONG TERM...(Thursday night through Wednesday)
Issued at 236 PM CDT Wed Sep 28 2016
Upper ridging dominates much of the region through the week as the
closed low remains nearly stationary over the Midwest. May see some
remnant high clouds from precipitation towards Missouri, otherwise
should expect highs in the lower to middle 70s and light winds
through Saturday. Morning lows gradually increase with the afternoon
temps from the upper 40s Friday morning to near 60 degrees on
Tuesday. Will continue to monitor the next system to impact the area
by late Saturday evening, possibly Sunday as a weak embedded wave
ejects from the upper trough axis digging south over the Pacific
Northwest. Have mentioned slight chances for thunder through Monday
for north central areas, however mid level lapse rates are generally
weak and confidence is low for any precipitation until Tuesday as
the main system lifts out into the Central Plains. The latest runs
of the ECMWF are more progressive with the system quickly pushing
north by Wednesday, while the GFS continues it slower progression
and therefore prolonged chances for rain after Tuesday. A blend of
the two with previous versions was the best compromise at this
time.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1223 PM CDT Wed Sep 28 2016
VFR is expected for the majority of the period, although there is
a chance for some BR/FG early morning primarily at TOP/FOE. The
RAP has been persistent with stratus, but has been the only model
to do so. Expect skies to be mostly clear which would allow for
some patchy fog formation but right now confidence is not high
enough to include in this TAF issuance.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Heller
LONG TERM...Prieto
AVIATION...Heller