Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/14/16
Area Forecast Discussion
National Weather Service Albany NY
1053 PM EDT TUE SEP 13 2016
.SYNOPSIS...
A cold front dropping southward from Canada will cross the area
on Wednesday, bringing the next chance of showers and thunderstorms.
High pressure will build back in by Thursday, bringing cooler and
drier weather.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
00Z NAM spins up a some rogue showers across central CWA tonight.
However, with evidence neither from radar nor satellite and no support
from the HRRR or RAP have continued with dry forecast.
Latest HRRR shows showers approaching northwest CWA in the 10-12Z
period. Going forecast offering chance POPS has this well covered.
With some added cloud cover and a persistent southerly breeze in
most spots, temperatures will be milder with mainly upper 50s to
lower 60s for lows. There will be some fog in wind sheltered
valleys mainly between 04z and 10z.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
On Wednesday...Expect an increasing chance of showers and
thunderstorms as the cold front starts to drop southeast through
the forecast area. The greatest threat will be during the
afternoon and early evening hours. Highs on Wednesday will be in
the mid 60s to mid 80s. MLMUCAPES rise to 1000-2000 J/kg along a
narrow band ahead of the front Wednesday afternoon, 0-6 km bulk
shear reaches 35-60 kts Wednesday afternoon, and H8-H7 lapse rates
5.5 to 7.5 C/km, and PWATS rise to 1.5 to 1.67 inches.
Will linger slight to low chance pops into Wednesday evening as
the upper trough axis pushes through. Otherwise, expect drying
conditions overnight and gradually clearing skies after midnight
with a northerly breeze developing in wake of the cold front. Lows
Wednesday night are expected to be in the mid 40s to mid 50s.
On Thursday...Expect dry weather and cooler conditions as a large
ridge of high pressure builds into the region. Highs are expected
to range from the mid 60s to mid 70s.
Thursday night and Friday will continue to be dry as high pressure
builds over the region Thursday night and then slides off the New
England coast on Friday. Lows Thursday night will be in the 40s
with highs on Friday in the upper 60s to mid 70s.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
High pressure will move off the New England coast Saturday AM. A
warm front will move through the region Saturday. Guidance may be a
tad too fast with brining precip into our area. The first part of
Saturday should remain dry. Will include a chance of showers and
thunderstorms for the second half of the day. High temperatures on
Saturday will be above normal with highs in the mid to upper 70s.
Saturday night and Sunday...a cold front will start to approach the
region. There is a bit of uncertainty in guidance with how fast the
front will clear the area. Model guidance may be too quick with
cold frontal passage for Sunday. At this time...have kept
precipitation in forecast into Monday. High temperatures on Sunday
will be in the upper 70s with lows around 60.
Monday...With uncertainty of timing of front...will include low
chance of pops for Monday. High temperatures will be in the 70s with
lows in the upper 50s to lower 60s. By Tuesday...will be between
systems. Have removed chances of precipitation for Tuesday.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
High pressure will slowly move off the New England Coast tonight.
An area of low pressure with its associated cold front will
approach the region on Wednesday. Clouds will start to be on the
increase early Wednesday AM.
More clouds and light wind than previous nights. With this
thinking, believe that ALB and POU will remain IFR-free. POU
likely to see some MVFR BR. Albany too will see some BR, but
should hold at VFR. For GFL, expect this site to decouple, so
likely will get to IFR BR/FG. Have allowed for IFR to set in in
the 04-06Z period via TEMPO at GFL. At PSF, also allowing for IFR
BR/FG, but holding off until after 06Z there.
Front will approach the region on Wednesday. Have provided a rough
idea of timing precipitation onset via "VCSH". Still some
questions as to timing of front and likelihood of precipitation at
terminal sites to go with anything more definite (e.g., SHRA).
There could be some thunderstorms with the front too. However,
timing and potential to impact a terminal not clear now. Best
chances for thunder would be ALB south and east in the afternoon.
Not enough confidence to include VCTS.
Outlook... Wednesday Night: Moderate Operational Impact. Chance
of SHRA...TSRA. Thursday: No Operational Impact. NO SIG WX.
Thursday Night: No Operational Impact. NO SIG WX. Friday: No
Operational Impact. NO SIG WX. Friday Night: No Operational
Impact. NO SIG WX. Saturday: Low Operational Impact. Isolated
SHRA. Saturday Night: Moderate Operational Impact. Scattered
SHRA...TSRA. Sunday: Moderate Operational Impact. Scattered
SHRA...TSRA.
&&
.FIRE WEATHER...
A cold front dropping southward from Canada will cross the area
on Wednesday, bringing the next chance of showers and thunderstorms.
High pressure will build back in by Thursday, bringing cooler and
drier weather.
Relative humidity values will recover to 85 to 100 percent
tonight, drop to 50 to 75 percent on Wednesday, recover to 85 to
100 percent Wednesday night, and drop to 40 to 50 percent on
Thursday.
Winds will be southwest at 5 to 10 mph tonight, west to southwest
at 5 to 10 mph on Wednesday, northwest at 5 to 10 mph on Wednesday
night, and north at 5 to 10 mph on Thursday.
&&
.HYDROLOGY...
Dry conditions are expected through tonight with high pressure
remaining in control. The next chance of showers and thunderstorms
arrives on Wednesday, as a cold front moves across the area.
Rainfall amounts will vary based on convective coverage with most
areas receiving between a tenth and a third of an inch, but any
rainfall will have minimal impact on area rivers and streams.
Dry conditions will return for Thursday and Friday, as another
area of high pressure builds into the region.
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...11/JPV
NEAR TERM...OKeefe/11
SHORT TERM...11
LONG TERM...VTK
AVIATION...VTK/OKeefe
FIRE WEATHER...11
HYDROLOGY...11/JPV
Area Forecast Discussion
National Weather Service Gaylord MI
1145 PM EDT TUE SEP 13 2016
.UPDATE...
Issued at 949 PM EDT Tue Sep 13 2016
Cold front has pushed SE of our CWA late this evening...with
generally light northerly flow/CAA in progress behind this
boundary. Shower activity has exited with the front...leaving
mainly cloudy skies in its wake. A small area of showers has
redeveloped over Central Wisconsin along the northern periphery of
a weak wave that has developed along the SW end of the cold front.
Larger area of more organized/stronger convection continues to
develop over Iowa and Northern Missouri right along the wave and
the front. Only the HRRR has picked up on the light precip over
Central Wisconsin...but even this model dissipates this precip
before it reaches Michigan. Still can`t rule out the outside
possibility that the northern fringe of this wave and resulting
precip may clip our far southern CWA overnight. Will therefore
leave the slight chance of showers in the overnight forecast for
locations along and south of M-55. The rest of our CWA will remain
mostly cloudy and dry overnight. Low temps in the upper 40s to mid
50s still looks reasonable.
&&
.SHORT TERM...(This evening and overnight)
Issued at 351 PM EDT Tue Sep 13 2016
High impact weather potential: None.
Overview: Mid level short wave trough is advancing into the
northern lakes region with an upper jet streak stretching from the
upper Midwest into Canada. Afternoon surface analysis reveals
weak-ish sfc wave across the straits/northern Lake Huron area
with a cold front snaking down through NW lower Michigan and on
into SE Wisconsin. Several thin lines of showers/dz have developed
along the front across the tip of the mitt into NW lower Michigan
and finally making steady progress southeastward with the front.
Tonight: Cold front and associated showers will slip SE through
the rest of the CWA through early evening. We never had a chance
to warm a ton today with all the clouds/earlier showers around,
although temps have clawed into the middle 70s across the SE
counties producing a thin axis of instability down that way. Thus,
cannot fully rule out additional thunderstorm possibilities before
the front pushes through the area.
Meanwhile, looking upstream there is another surge of mid level
moisture behind the front, from the plains into the Midwest
(across Iowa and southern Minnesota) with a few showers advancing
into those areas. That activity is looking to slide through
southern lower Michigan during the overnight hours into Wednesday
morning, with the southern tier of counties of this CWA
potentially getting skimmed during the overnight hours. Thus, plan
to keep some lower end shower chances going south of M-72
overnight.
Wednesday: High pressure and drier air make a big push into the
region through the day. May start out with a bit of cloud cover in
the morning, but we should wind up with a fair amount of sunshine
for the afternoon with some diurnal CU development. Certainly
cooler however, with highs in the middle 60s to around 70.
.LONG TERM...(Wednesday through Tuesday)
Issued at 351 PM EDT Tue Sep 13 2016
High impact weather potential: None.
Upper ridge over the Great Lakes amplifies slightly in response to
approaching trough/sfc low over the plains Wednesday night. This
strengthens surface high over MI into Friday. By Friday...Gulf opens
up and high moisture air makes a run at northern MI ahead of the
upper trough and surface low.
Fire Wx...Not much going on Fire Weather-wise as high pressure moves
over the Great Lakes region. Winds lighten up tonight and stay light
through Thursday/Friday. RH levels are expected in the 50 percents
Wednesday and 40 percents Thursday. High temperatures should be in
the 60s Wednesday with around 70 on Thursday and Friday. The next
chance for precipitation arrives late Friday.
FARINA
Primary concern for the extended remains weekend rain chances. A
positively tilted, cutoff low is finally getting over land, visible
on water vapor over CA/NV. Better sampling of this should help
refine the timing of the system as it moves through the plains and
toward the Great Lakes. This system will bring rain, with Friday
night into Saturday morning looking to be the most likely time. Some
lingering showers could remain through the day Saturday, with a bit
of lake enhancement not out of the question for Sunday as cold H8
air filters in behind the system.
MAYHEW
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1145 PM EDT Tue Sep 13 2016
Overall conditions will remain VFR/occasionally high MVFR thru
Wednesday night as high pressure builds into the region. Some
patchy fog will develop within inland areas overnight...but our
TAF sites should remain generally VFR. Winds will remain from the
N/NW below 10 kts thru the TAF forecast period.
&&
.MARINE...
Issued at 351 PM EDT Tue Sep 13 2016
Winds will veer into the NW-N tonight. Some gustiness anticipated,
although winds/waves will remain below small craft advisory
levels. Weakening winds for midweek as high pressure builds into
the region.
&&
.APX Watches/Warnings/Advisories...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...MLR
SHORT TERM...Adam
LONG TERM...Mayhew/Farina
AVIATION...MLR
MARINE...Adam
Area Forecast Discussion
National Weather Service Denver/Boulder CO
808 PM MDT TUE SEP 13 2016
.UPDATE...
Issued at 808 PM MDT Tue Sep 13 2016
Showers are having a hard time surviving very far east on the
plains this evening as the airmass is just too stable and there`s
no significant synoptic scale lift. However, in the mountains we
continue to see scattered showers and isolated thunderstorms.
Those will likely continue through much of the night with slightly
better lift and instability there, while only isolated showers
expected to attempt to drift out onto the plains late this
evening (still low thunder threat in Douglas county)
Main change was to add more fog on the plains back to the I-25
Urban Corridor. There is already a Denver Convergence Vorticity
Zone (DCVZ) in place and this should remain nearly stationary
through the night and into Wednesday morning. As a result, the
threat of fog developing will increase from Fort Collins down to
at least the northern sections of Denver by daybreak. The only
question is how much boundary layer cooling we get as there is a
decent deck of mid and high level clouds streaming overhead and
that would hinder extent of fog.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 204 PM MDT Tue Sep 13 2016
Southeast low level flow around a surface high over the Central
Plains is producing downslope north of the Palmer Divide providing
some clearing. This southeast flow is also keeping the stratus
over northern parts of the Urban Corridor and also the eastern
plains. Expect the stratus to continue to erode from the edges
through the afternoon. Low level flow eventually turns south-
southwest which will bring slight drying and help erode the
stratus this evening. Surface winds will remain south to southeast
over the eastern plains and into the Greeley-Fort Collins area. So
expect low clouds for tonight and Wednesday morning in these
areas.
As far as precipitation goes, airmass is somewhat unstable over
the higher terrain where scattered showers and isolated
thunderstorms are expected form. Most of the convection should
dissipate as it moves off the higher terrain and into more stable
air. However, a weak wave over Utah may provide enough lift to
help showers persist through the evening as they move onto the
plains. Some models, such as the HRRR show showers through about
06z. Will keep scattered pops in the forecast for this.
On Wednesday, partial clearing will allow temperatures to climb
into the 70s for most of northeast Colorado. CAPE will climb up to
1000 J/kg. This instability combined with a weak wave aloft is
expected to produce scattered afternoon thunderstorms. Area of max
instability will be small, so the threat for severe weather should
be low, though a couple of severe storms will be possible. Because
of the cool airmass, small hail will be possible with most of the
thunderstorms.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 204 PM MDT Tue Sep 13 2016
The closed low/upper trof now over Northern California will slowly
move Northeast into the Northern Rocky mountain region Wednesday
night and Thursday. This trof will send an associated jet streak
across Colorado with a batch of showers and storms moving over the
plains through Wednesday evening. Some of these storms could get
quite strong with ample shear and surface based capes of
1000-1500j/kg. As the upper trof sweeps across the Northern
Rockies and high plains Thursday night, an associated cold front
will push southward over Eastern Colorado with a reinforcing shot
of cooler air. Thursday will be drier yet remaining on the cool
side under a more subsident airmass behind the trof. However there
will still be enough moisture for isolated storms mainly over
higher terrain.
For Friday and Saturday, Colorado still under some weak influence
of sheared out trof with some lingering moisture and shallow
upslope flow. This will result in continued chance for
showers/isolated thunderstorms especially over mountains and east
slopes. Drier again for Sunday and Monday under a bit drier West
to Southwest flow.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 808 PM MDT Tue Sep 13 2016
Denver Convergence Vorticity Zone (DCVZ) is already in place and
should remain nearly stationary overnight. As a result, a
favorable pattern exists for fog formation tonight at KBJC and
KDEN with light N/NW flow. KDEN may briefly shift back to SW
overnight before turning NW again around daybreak. There are some
mid and high clouds streaming overhead which would limit cooling
and threat of fog development, but at this time the pattern in
conjunction with HRRR output suggests pretty high potential for
fog with 1/4-1/2SM visibility in the 11Z-15Z time frame. Should
see quicker clearing on Wednesday with increasing boundary layer
flow and very shallow moisture/upslope profile. Airmass
destabilizes enough for a chance of thunderstorms after 21Z. Could
still see an isolated rain shower this evening til around 07Z.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...Meier
LONG TERM...Entrekin
AVIATION...Barjenbruch
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1203 AM EDT WED SEP 14 2016
.AVIATION...
Activity has been on the increase again as another burst in forcing
works along the sagging cold front. Given spacing of spells this
particular development appears to have been forced by a possible
gravity wave. Bulk of the model data continues to support a solution
that depicts additional development over the southern half of the
cwa after 06Z. Current trends on radar casts some doubt on
additional development between 08-11Z, however, will exhibit
patience. MVFR cig height have corresponded to a true northerly wind
direction, relying on initial low level cold air advection. Model
data supports only a slow evolution to ceiling heights today before
loss of diurnal heating and dry air advection causes skies to go
clear wed night.
at DTW...Will be dealing with some shower and thunderstorm activity
intially passing north of the terminal. However, still expecting max
of frontal forcing between the 07 and 10Z timeframe.
//DTW Threshold Probabilities...
* High for cigs below 5 kft agl tonight.
&&
.PREV DISCUSSION...
Issued at 835 PM EDT Tue SEP 13 2016
UPDATE...
Issued an update to the forecast early this evening to push up the
start time of chance PoPs for tonight. Shower and isolated
thunderstorm activity has developed in response to an
introduction of deeper moisture content from the wave lifting
across the central Great Lakes into a column containing adequately
steep midlevel lapse rates. Convection over portions of southern
Lower Michigan is along a corridor of enhanced surface
convergence. The thunderstorm development over Saginaw Bay is
occuring in close proximity to the actual surface cold front
and could be getting a marginal boost from the relatively warmer
waters (weak per forecasted low lapse rates and satellite derived
water temperatures). Change in instability over change in time
appears to be going down in the latest couple of RAP based MSAS
analyses and suspect already seen the height of the convective
vigor with tops over Saginaw Bay up to 30 kft agl. Could be a
struggle to see more thunder tonight besides the Huron County
storm but will keep it in the forecast. Otherwise, best time
period for better confluence over the southern forecast area
really doesnt appear to increase until 7 to 11Z. Not enough to
really force a required increase to PoPs.
PREV DISCUSSION...
Issued at 349 PM EDT Tue SEP 13 2016
DISCUSSION...
The MVC which rolled across nrn Lower Mi late this morning is
already exiting east of Georgian Bay. This wave has forced a mid
level theta e ridge into the Saginaw Valley/thumb region this
afternoon. Remnant convection along this mid level boundary weakened
as it worked into Se Mi where there remains a fairly strong mid
level capping inversion in place. Most of the forecast area has
actually been experiencing a good deal of sunsine this afternoon,
with strengthening s-sw winds pushing temps around the 80 degree
mark. Recent sfc analysis shows a cold front extending across NW
Lower Mi. This front will be driven south across the forecast area
tonight as the mid level trough now rotating across nrn Minnesota
slides across Lake Superior and Upper Mi. The sfc cold front is
forecast to exit south of the forecast area between 09Z and 12Z.
Despite the mid level theta e ridge pushing south across the rest of
the forecast area during the evening and the approach of the sfc
cold front, weak instability and meager large scale ascent suggests
nothing more than a slight chance of convection this evening.
Slightly better mid level height falls will overspread srn Mi
overnight with the passage of the upper trough across Lake Superior.
This and the associated ageostropic response within the entrance
region of an upper jet max which slides into ern Ontario overnight
will result in an increase in low to mid level frontogenesis across
Se Mi. The response will be within the elevated portion of the
front, thus post sfc front. The timing is expected to be mainly
between 06z and 12z Wed morning, with the better forcing likely
targeting locals along/south of the I-69 corridor. This will support
chance type pops during the predawn hours through the morning
rush. Despite the lack of sfc instabily, low to modest instability
aloft will still support a chance for a few late night
thunderstorms.
High pressure will quickly build across the nrn Great Lakes
Wednesday ahead of a mid level ridge overspreading the upper MS
valley. Post frontal cold air advection and northerly flow will
likely contribute to an abudance of lake clouds during the day. As
cold air advection and daytime heating deepen the convective coud
depths, a few light showers/sprinkles are possible Wed afternoon,
especially across the thumb region immeiately downstream from Lake
Huron. The clouds and low level cold air advection will hold
daytime temps mainly in the upper 60s and low 70s.
The advent of warm/moist conditions pushing into the region will
bring the chance to see showers and thunderstorms Friday into
Saturday, as temperatures peak in the mid-70s for a daytime high. We
will continue to have the chance to see some lingering showers
Sunday as a weak cold front pushes through the region, before drying
out for the early part of next week. Temperatures are expected to
stay seasonal, with highs capping out in the low to mid-70s Sunday
into Tuesday.
MARINE...
Southwest wind will become moderate to fresh northwesterly behind a
cold front tonight. Wind will continue to veer to northeasterly into
Wednesday morning, causing significant wave heights to build to
around 3 feet. At this time, it does not appear that small craft
advisory conditions will be reached. Marine weather will then remain
quiet for the remainder of the week until a chance of thunderstorms
arrives during the weekend.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
AVIATION.....DG
UPDATE.......CB
DISCUSSION...SC/AM
MARINE.......JVC
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Green Bay WI
920 PM CDT TUE SEP 13 2016
Updated aviation portion for 06Z TAF issuance
and new information added to update section
.UPDATE...
Issued at 911 PM CDT Tue Sep 13 2016
With the mid-level baroclinic zone in the area, it`s obvious that
precipitation chances tonight are going to be greater than
initially expected. One band of showers was heading eastward into
central Wisconsin, while a second area just popped up over
central Door county. Initally thought much of the precipitation
would be sprinkles and fail to measure, but the higher
reflectivities and brief moderate rain at K3D2 suggest otherwise.
Will add chance PoPs for much of central and east-central
Wisconsin, mainly for early tonight. Will taper them off and shift
them southeast with time.
Although north-central Wisconsin has cleared, colder air arriving
over Lake Superior still supports clouds and possibly some
showers/sprinkles moving back into that area later tonight. Also
need to watch winds in east-central Wisconsin, as some of the
high-res models suggest they could swing around and come off the
Lake and Bay by morning.
Updated product suite will be out ASAP.
&&
.SHORT TERM...Tonight and Wednesday
Issued at 231 PM CDT Tue Sep 13 2016
The latest RAP analysis and satellite/radar imagery show a cold
front exiting eastern WI early this afternoon. However, scattered
light showers and drizzle are lingering behind the front and mainly
over northeast WI. Expect a chance of light precip will depart
northeast WI later this afternoon. Behind the front, colder and
drier air is filtering southeast across the state. Combined with
unstable conditions over western Lake Superior, steepening low level
lapse rates are producing a cu field behind the stratiform cloud
mass right over north-central WI. Not out of the question that a
few showers could also pop here late this afternoon as well. Besides
small precip chances, cloud trends are the main forecast concern.
Tonight...Cold advection will continue behind the front tonight, as
Canadian high pressure settles across the region. Think most light
precip will have exited eastern WI behind the front by the start of
the evening. However, the tail of a shortwave passing over Lake
Superior in addition to increasing unstable conditions could lead to
a few showers over far northern WI during the evening, before
becoming confined to the lake effect belts in Vilas Co. overnight.
Cloud cover is more difficult to project. Low stratus will likely
exit to the east this evening, but plenty of broken strato-cu lies
upstream over the northwest part of the state. In addition, a large
mid and upper cloud shield will spread across much of central and
northeast WI by this evening. The end result should yield mostly
cloudy conditions through the evening, then partial clearing
arriving from the west overnight. Cooler with lows in the mid 40s
north to mid 50s south.
Wednesday...Canadian high pressure will be building into the region
through the day. Some clouds may linger over far northern WI during
the morning before the flow backs around midday. Though flat
diurnal cu is possible elsewhere, should see a partly cloudy to
mostly sunny day. High temps mainly in the mid to upper 60s.
.LONG TERM...Wednesday Night Through Tuesday
Issued at 231 PM CDT Tue Sep 13 2016
Primary focus during this period is the frontal system and short
wave trough late this week into early this weekend.
An upper ridge and surface high pressure system will drift over
the region Wednesday night into Thursday evening. 850 mb temps
from 4 to 6 above zero with light winds and a dry air mass may
produce patchy to areas of frost across parts of north central
wisconsin Wednesday night. Longer nights may promote fog
development as well. cooler air over the lakeshore regions may
produce more lake clouds Wednesday night into Thursday if the
onshore wind can remain persistent.
Return flow begins Thursday as the high pressure system drifts
eastward and a low pressure system approaches from the west. This
low pressure system is associated with an upper trough which
originated over the western states.
Medium range progs track the upper trough over the Northern
Plains starting Thursday night before departing the northern
Great Lakes region later Saturday. Best dynamics and instability with
the warm air advection and height falls over the northern plains
and northwest Wisconsin late Thursday night into Friday morning,
then with the fropa later Friday or Friday evening over eastern
Wisconsin. A dry slot working over the area later friday night
may end precipitation a bit quicker. Upper low and cyclonic flow
with wrap around showers may work back into mainly northern
Wisconsin on Saturday.
Another high pressure ridge with surface high pressure will build
into the region Sunday into the new work week for another quiet
period of weather and gradually warming temperatures to slightly
above normal.
Getting beyond this forecast period and confidence is low, but
do note the GFS continues to produce a very deep trough over the
northern plains by mid week next week with pwats climbing to near
2.00 inches. The ECMWF on the hand trended from a zonal pattern
to a broad upper ridge over the mid section of the country for
much of the week. The ECMWF is there warmer and holds of any
precipitation until late next week.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 911 PM CDT Tue Sep 13 2016
Multi-layered clouds will persist across the area tonight. Most of
the clouds will have VFR bases, though some MVFR conditions could
develop near Lakes Michigan and Superior by late tonight.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE.........Skowronski
SHORT TERM.....MPC
LONG TERM......TDH
AVIATION.......Skowronski
Area Forecast Discussion
National Weather Service Wilmington NC
1049 PM EDT Tue Sep 13 2016
.SYNOPSIS...
A tropical wave over northern Florida may further develop as it
meanders to the north, toward GA and southern SC by Thu before
dissipating on Fri. At the same time, a cold front will drop
southward across NC during Thu, and across SC by early Fri
before stalling. In its wake, high pressure will build in from the
northeast Fri thru Sat, and from the east on Sun. The next cold
front will push across the area late Monday of next week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
As of 1045 PM Tuesday...Have tweaked min temps, hourly sfc temps
and dewpoints upwards overnight for all areas, more-so for
locations that experience thicker cloudiness and the increased
threat for pcpn during the pre-dawn Wed hours.
Previous.....................................................
As of 745 PM Tuesday...This update is geared toward the
redistribution of POPs and cloudiness for the remainder of this
evening and overnight into daytime Wed morning. The latest radar
mosaic trends indicate the decrease in pcpn coverage this evening.
The latest HRRR model also illustrates the current pcpn trend in
unison with the the mosaic radar trend. The latest HRRR and
HiResWRF for the most part indicate the re-development of pcpn
over the adjacent Atl Waters during the 3-6 hrs leading up to
sunrise Wed, mainly south of Cape Fear. Some onshore movement
occurs by sunrise Wed, mainly across the ILM SC coastal counties.
In general, lowering POPs several categories over land areas from
now through the mid pre-dawn Wed hours. Followed by, a rise in
POPs from the late pre-dawn Wed hrs into daytime Wed, with the
most changes occurring across the ILM SC Counties and the
immediate coast of the ILM NC counties. The cloudiness also to
follow this similar path. The ILM CWA, especially the pcpn-free
areas, may see patchy fog overnight. Would increase the fog, both
coverage and intensity, but enough cloudiness is progged to
prevent this occurrence. Min temps look in the ballpark with
very little or no tweaking applied.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
As of 3 PM Tuesday...Latest from NHC indicates the low pressure over
Florida today has a 40 percent chance of developing into a tropical
cyclone within the next few days. Although the low will only slowly
drift north-northwest through the period, and likely still be over
southern GA on Thursday, moisture associated with it will be drawn
northward as a mid-level shortwave traverses the northeastern CONUS,
and a ridge sets up off the southeast U.S. coast. Deep moisture will
be poised along and just off the coast Wednesday and Thursday. Have
raised PoPs a bit, with the highest values across coastal northeast
SC. With precipitable water values approaching 2.25", there will be
potential for locally heavy rainfall. The front will act to suppress
the surge of moisture into the northern CWA, but as it slows, it
will enhance the potential for heavy rainfall across coastal SC on
Thursday.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 3 PM Tuesday...Eastward passage of an upper ridge axis across
the Carolinas Friday into the weekend will lock a high pressure
wedge over the area, keeping deeper moisture and low pressure
positioned to the south over N FL and SE GA. The wedge will release
its grip late weekend into Monday as height fall aloft ensue. Dry
mid-level air will limit rain-rate potential but ample moisture
below 700 MB should allow a few showers or an isolated TSTM with
maximum temperatures in the middle 80s, right around normal for this
time of year. Southerly flow will commence early next week as the
surface high slips off the coast. This may help draw slightly deeper
vapor content northward, but height rises associated with an
expanding upper ridge from the south may suppress upward vertical
motions so advertised pop values at this time to remain isolated
to scattered.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
As of 00Z...Convection is all but over. Some convective debris at
least through this evening. Look for more stratus/fog again through
the overnight hours. Offshore moisture will ride up the coast after
midnight, with the Myrtles seeing precip toward morning and a few
hours later for ILM. Look for mainly MVFR conditions in the
convection, briefly IFR at times by mid to late morning.
EXTENDED OUTLOOK...Chance for convection through Friday with a weak
front stalled in the area. Brief bouts of IFR are possible in the
heavier convection.
&&
.MARINE...
NEAR TERM /Through Tonight/...
As of 1045 PM Tuesday...Have increased winds/wind gusts by 5 kt
over AMZ256, Murrells Inlet to South Santee River, overnight into
daytime Wed, still below any advisories. The sfc pg has become a
bit tighter over the extreme southern portions of the ILM SC
Waters. This a result of the formation of Tropical Storm Julia in
the vicinity of Jacksonville Florida. Julia is expected to meander
northward overnight and Wed, staying inland as it tracks into
southern GA. NHC progs it to dissipate Wed night or Thu across
inland GA. The significant seas will basically run 2 to 3 ft north
of Murrells Inlet and 3 to 4 ft south of the inlet ie. AMZ256.
Dominant periods will be 4 to 5 seconds, ie. easterly wind driven
waves. Will have to monitor the seas due to the 7 to 8 second
pseudo swell from the ese-se which may be underdone by wavewatch3
and locally run swan models.
Previous.....................................................
As of 745 PM Tuesday...This update mainly concerned with pcpn
coverage thruout the night and into daylight Wed. Initially, will
lower POPs across the local waters this evening then ramp them
back up during the pre-dawn Wed hrs across the waters south of
Cape Fear. This due to the nocturnal environment over the 80+
degree Atlantic SSts, along with some forcing aloft from the
tropical wave having moved inland and near the GA-FL state line by
daybreak Wed. Have held onto the wind scheme across the local
waters this evening and overnight, but may apply an upward trend,
especially across the ILM SC Waters, at the next update if the
pinched sfc gradient pushes any further north.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 3 PM Tuesday...With a relatively slow northward drift of the
Florida low pressure through the period, the pressure gradient is
not expected to increase significantly Wednesday. However it is
important to note that the NHC has given this low a 40 percent
chance of developing into a tropical cyclone over the next few
days, and if this occurs, marine conditions could begin to
deteriorate significantly on Thursday, especially south of Little
River Inlet. Onshore flow will be the rule this period, with
speeds of 10 knots or less Wednesday, increasing to 15 knots by
Thursday. Seas of 2-3 feet Wednesday will build to 3-4 feet on
Thursday.
LONG TERM /FRIDAY THROUGH SUNDAY/...
As of 3 PM Tuesday...With a tropical low or wave over N FL this
period and high pressure north of the waters, a deep, moderately
strong easterly fetch will prevail. Although winds may not reach
advisory speeds, seas will become elevated in easterly swell waves
and an `exercise caution` statement or advisory for seas is not
entirely out of the question, especially considering a moderate
east chop will be riding the swell waves. Scattered showers and
isolated TSTMS will remain in the mix this period. dominant wave
periods will be shared between 10-11 second E swell and 4-6 second
wind-waves from the E.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.
&&
$$
SYNOPSIS...DCH
NEAR TERM...DCH
SHORT TERM...CRM
LONG TERM...MJC
AVIATION...RGZ/DL
Area Forecast Discussion
National Weather Service Lincoln IL
906 PM CDT TUE SEP 13 2016
.UPDATE...
Issued at 906 PM CDT Tue Sep 13 2016
Spotty showers and storms have developed along the cold front that
has pushed south of I-72 early this evening. What appeared to be a
pre-frontal trough earlier was the actual cold front. The front
will continue to drift slowly to the southeast overnight, with
showers and isolated storms possible through tomorrow across a
majority of central and southeast Illinois. The latest RAP output
continues to indicate precip chances will increase north of I-70
the rest of tonight. The HRRR still keeps the focus mainly N of
I-72 overnight, then dissipates precip Wed morning in favor of
redevelopment along and south of I-70. Have expanded precip
chances farther southeast toward I-70 the evening, more in line
with RAP, which is supported by radar trends.
Temperatures tonight will be generally held a little warmer than
might be expected behind a cold front due to persistent cloud
cover and periodic showers. Have kept the upper 50s near
Galesburg, with low to mid 60s in the remainder of the forecast
area. Winds will be NW behind the front, and remain light
southerly or variable ahead of the front.
Main updates this evening were done to the weather/PoPs, with
minor changes to temps and dewpoints. The latest forecast info is
already available.
&&
.SHORT TERM...(This evening through Wednesday)
ISSUED AT 308 PM CDT Tue Sep 13 2016
Cloudy weather in the Midwest today with warm temperatures is slowly
giving way to a weak cold front moving across the region. As the
evening progresses...chances for showers and thunderstorms will
creep from NW to the I-55 corridor by midnight. Although this cold
front is scheduled to move through, showers and thunderstorms at
this moment are limited by weak ascent, weak shear, and ultimately a
decent cap over the region. Showers already along the boundary to
the NW are having a hard time generating much on radar. A weak MCV
moving along the line is also not resulting in much activity, and
that had previously been the focus for the models evening
developments. Overall, the chances are there, but have at least
adjusted the wording to more a function of coverage instead of
uncertainty...opting for scattered at best. Winds remain weak
through the overnight, even with the wind shift expected with the
frontal boundary. Precip chances will continue through tomorrow,
ending NW to SE by the end of the day.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 308 PM CDT Tue Sep 13 2016
Quiet weather is expected across central and southeast Illinois to
start the period, with upper-level ridging and surface high pressure
dominating the local weather. However, this quiet weather is likely
to be short lived as one or more weather disturbances impact the
region into early next week.
An upper low, currently centered over California and Nevada, will
open on Wednesday and slowly track northeast. The remnant wave is
expected to reach the northern Plains Thursday night, and upper
Great Lakes/northern Ontario region by Saturday morning. This wave,
and the associated frontal boundary will produce an extended risk of
showers/storms locally from late Thursday into late Saturday. Sided
with the slower side of guidance in bringing rain chances back into
the area Thursday since upper lows are often broken down too quickly
and the fact that the local airmass will initially be very dry.
There will be a break in the rainfall threat later in the weekend,
but this break also has the potential to be short lived. The models,
to varying degrees, have been reloading the western U.S. trof once
the current upper low departs and ejecting periodic disturbances
toward the region. However, the guidance has only fair agreement
with the details at the moment, and has shown considerable run-to-
run variability. So, plan to keep PoPs quite low to start next work
week until a better consensus is reached.
Temperatures through the period should remain fairly close to normal
for mid-September.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 653 PM CDT Tue Sep 13 2016
Radar loops shows a pre-frontal wind shift/trough drifting south
of Lincoln, extending from Pittsfield to Taylorville to Champaign.
That line has become the focus for showers just west of
Pittsfield. The latest RAP model energizes that line with showers
by mid-evening, with additional showers farther northwest along
the Illinois River. The latest HRRR is not acknowledging the
southern line of precip, and keeps the focus farther northwest
closer to the approaching cold front. Have included precip earlier
for the southern terminals of SPI, DEC and CMI in light of the
radar trends and RAP output. Thunderstorms will be isolated, as
instability weakens after sunset. Have opted to not include
thunder in the 00z TAFS. Precip chances beyond this evening will
be tied to the cold FROPA later tonight into Wed morning. Have
included periods of prevailing rain along the front for a few
hours as it progresses to the southeast through central IL. IFR
and LIFR ceilings will be possible close to the front and in the
post-frontal air mass. IFR visibility in rain and fog will be
possible as well close to the front around sunrise.
Conditions will gradually improve to MVFR behind the front
through the day on Wednesday. Winds will shift from W-SW to
NW between 06z and 11z. Winds will settle out from the N-NE during
the day on Wed, as high pressure builds into the area.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...Bak
AVIATION...Shimon
Area Forecast Discussion
National Weather Service Indianapolis IN
1141 PM EDT TUE SEP 13 2016
.UPDATE...
The AVIATION Section has been updated below.
&&
.SYNOPSIS...
Issued at 244 PM EDT Tue Sep 13 2016
A weak cold front will bring chances for rain tonight and Wednesday,
but a stronger system will bring better chances for rain during the
early part of the weekend. However, temperatures will remain near to
above normal into next week.
&&
.NEAR TERM.../Rest of Tonight/
Issued at 940 PM EDT Tue Sep 13 2016
Updated the forecast to push back the timing of arrival of any
thunder into the northwestern and northern counties until after 4
am, and even then only include a slight chance to account for
forecast elevated instability. Rest of the area remains dry
overnight. Going forecast lows in the low to mid 60s look on track
compared with current dew points and latest lows from the RAP and
HRRR. Previous discussion follows...
Hi Res Rapid Refresh has been consistent in bringing some scattered
showers into the extreme northwest forecast area this evening in
this higher dewpoint air. The GFS also shows this possibility,
although it is overdone in coverage of rainfall and QPF. Thus have
added some slight chance PoPs to the far northwest later this
evening.
The remainder of the northwest forecast area as well as the far
north will have to wait until overnight for some low rain chances,
as a cold front approaches the area. Forcing is not great with this
feature, so kept PoPs in chance category or lower.
Temperatures will be warmer tonight with the higher moisture content
moving in. A model blend looks good.
&&
.SHORT TERM.../Wednesday through Friday/
Issued at 244 PM EDT Tue Sep 13 2016
Focus is on rain chances through the period. Models are close enough
that a blend was used for most items.
The cold front will move through the area on Wednesday. Best upper
support will remain well to the north of the area with an upper
trough. The forecast area initially is near the right entrance
region of an upper jet, but that moves away during the day as well.
Other negatives include lack of decent moisture and weak surface
convergence.
Thus will keep PoPs in chance category across the area on Wednesday.
What forcing there is will quickly weaken/move off before 00Z, so
will quickly lower PoPs during the late afternoon.
With the forcing gone by 00Z, will continue a dry forecast Wednesday
night. Will also continue a dry forecast on Thursday and Thursday
night as high pressure nudges into the area from the northeast.
However, will have to watch to see how far front actually moves
south of the area, as 850mb flow becomes southerly and moves over
the front during this period. This could spark some scattered
convection. Will continue to monitor.
Front returns north on Friday as upper flow becomes southwest once
again. This will result in low chances for rain across much of the
area.
A model blend continues to look good for temperatures through the
period.
&&
.LONG TERM /Friday Night through next Tuesday/...
Issued at 300 PM EDT Tue Sep 13 2016
Models indicate low pressure will track east across the great lakes
and a cold front will move across our region on Saturday. As a
result the first half of the weekend will be quite wet. Behind the
cold front weak high pressure will move to northern Indiana by
Sunday night and to the eastern great lakes late Monday or
Tuesday.
Overall model ensembles are in good agreement through the
weekend...but with some differences early next week. The GFS keeps
us dry late Sunday through Tuesday...while the 00Z Euro brings
another system our way late Monday and Tuesday.
The new 12Z Euro is trending slower in moving precip our way. As
a result will drop rain chances all areas Monday night and go no
more than slight chance POPS west Tuesday.
Temperatures will be slightly warmer than normal most of the period
with lows in the middle to upper 60s Friday night... cooling to the
middle 50s to around 60 by Monday and tuesday.
Highs will be in the middle to upper 70s north to around 80 south
through the period. In most cases...stayed close to a MOS blend on
temperatures.
&&
.AVIATION /Discussion for the 140600z tafs/...
Issued at 1141 PM EDT Tue Sep 13 2016
Mainly VFR conditions will be expected through 12Z. MVFR CIGS are
expected to invade after 12Z and persist into the middle of the
afternoon. A return to VFR CIG is expected by 00Z Thursday.
Radar early this morning shows SHRA near LAf diminishing and these
should dissipate near issuance time. Otherwise...HIgh CI will
continue to stream across the TAF sites and low dew point
depression will result in some MVFR fog at the rural taf sites.
Time heights and Forecast soundings show better lower level
saturation near 12z...persisting through the day in the wake of
the FROPA. At this time forcing appears weak and will continue to
use a mention of VCSH. As the front sags farther away on Wednesday
night...any VCSH will end and VFR CIGS look to remain.
&&
.IND Watches/Warnings/Advisories...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50/CP
SHORT TERM...50
LONG TERM....JH
AVIATION...JP
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
925 PM CDT TUE SEP 13 2016
.UPDATE...
925 PM CDT
Surface cold front boundary continues to gradually sag south
across counties south of I-80. Due to some convergence along
elevated 850 mb front and position of area in exit region of upper
jet, some isolated to widely scattered showers began to develop
early this evening. There should be an uptick in anafrontal
(post-frontal) shower coverage overnight, but overall not
expecting any widespread, heavy rainfall. Have pulled thunder
mention for most of the area. The best chance for any isolated
thunder to occur the rest of the night will be in east central
Illinois and west central Indiana, which in the LOT CWA would
include portions of Ford, Iroquois and Benton counties. Outside of
tweaks to hourly trends, low temperature forecast in the lower to
mid 60s east/southeast of I-55 and upper 50s to lower 60s
west/northwest of I-55 appears to be on track.
RC
&&
.SHORT TERM...
245 PM CDT
Through Wednesday...
A cold front lies across southern WI through eastern IA and is
slowly pushing southeast. Convective allowing models are over doing
precip development over the next few hours. However, the latest RAP
analysis shows around 1000 J/kg with little to no CIN to speak of. A
few light echoes are appearing on radar, but doubting that any
precip is reaching the ground. Expecting isolated to scattered
storms to form ahead of the front late this afternoon into this
evening. Best coverage will be along & south of I-88 this evening
and overnight. Shear is not fantastic so not expecting severe
storms. However, PWAT values are 1.25-1.5 inches and the front is
moving very slowly. Therefore some storms may produce heavy
downpours that may result in localized ponding. Winds become
northwest to north behind the front.
Winds turn northeast off of the lake Wednesday. Expecting a few lake
effect rain showers to form and push onshore in the morning thanks
to the elongated fetch and high lake induced CAPE values.
Conditions become more stable in the late morning, and showers come
to an end. Clouds are slow to clear, but cooler air moves in behind
the cold front. High temps tomorrow will be in the mid to upper 70s
away from the lake. Highs will be around 70 along the lake shore.
JEE
&&
.LONG TERM...
245 PM CDT
Wednesday night through Monday...
High pressure will settle east of Lake Michigan Wednesday night
into Thursday, which will maintain southeast flow across the region.
The cutoff low currently over California will be meandering
eastward across the Northern Great Plains on Thursday. This will
induce downstream ridging, which coupled with a drier low level
flow should keep precipitation to the west.
Eventually warm advection and height falls ahead of the approaching
low will eventually lead to an expansion of shower coverage, but
these forcing mechanisms appear to remain fairly weak even
Thursday night. We do still maintain southeast surface flow as the
upper low and surface convergence remain favored off to our
northwest which should limit the impacts. Still some disagreement
as to how much of the overnight activity survives into Friday
morning, therefore have maintained some chance pops, but the best
combination of moisture return and forcing would be later
Friday/Friday night when moisture transport/convergence is
maximized along the front. Diurnal timing would suggest just
showers.
Eventually the surface frontal trough will come through Friday
night into Saturday as the main upper low finally pushes east
across Lake Superior. High pressure returns Sunday for a sunny and
seasonal day with highs in the lower 70s. The high shifts east
Monday for warmer but still dry.
KMD
&&
.AVIATION...
For the 00Z TAFs...
Main concern initially will be a wind shift to nely associated
with a lake breeze boundary moving inland. The boundary has
already pushed through ORD and should reach MDW/GYY shortly after
issuance time. There is some question as to whether the boundary
will push through DPA given the swwd progression. Wind speeds
should initially reach up to 12-14kt but this should only be brief
before settling to under 10 kt.
The other concern will be associated with the progression of a
cold front dropping through swrn WI/nern IA. Expect that this
front will slowly but steadily push to the southeast and set up
nwly winds at portions of the area not impacted by the lake breeze
through the evening hours.
Eventually, as the center of high pressure slides east across the
upper Mississippi valley to the upper Great Lakes, winds will,
synoptically shift to enely tomorrow across all of the area.
Have backed off considerably on pcpn chances at the terminals.
Latest radar trends show little pcpn along the front and the high
res models have been handling this pcpn very poorly. So, have
maintained a vcsh mention in the TAFs associated with a maxima in
vertical velocities associated with a mid level shortwave moving
through the mid level flow. Otherwise, while there is a chance for
some sct shra overnight, confidence is now too low to keep any
pcpn mention in the forecast overnight.
In the cooler air behind the from, mvfr cigs are likely for the
overnight hours, but cigs should improve through the morning hours
with daytime warming.
&&
.MARINE...
245 PM CDT
A weak cold front will sweep across the Great Lakes region
tonight. Modest high pressure will develop across the plains
tonight. Northeast winds ahead of the high will lead to some
higher waves across southern Lake Michigan Wednesday, and lead to
hazardous conditions to small craft. The high will shift over the
lake Wednesday night and then to the Atlantic coast by Friday. Low
pressure across the northern Rockies/Plains will slowly drift to
southern Ontario by the weekend. This will result in lighter
southerly/southeasterly flow across the lake through Friday,
increasing some as the wind shifts southwest ahead of the low
Saturday before a weak cold frontal passage Saturday night.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Beach Hazards Statement...ILZ006-ILZ014...4 AM Wednesday TO 10
PM Wednesday.
IN...Beach Hazards Statement...INZ001-INZ002...4 AM Wednesday TO 10
PM Wednesday.
LM...Small Craft Advisory...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...4 AM Wednesday TO 10 PM Wednesday.
&&
$$
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Area Forecast Discussion
National Weather Service Melbourne FL
919 PM EDT TUE SEP 13 2016
.DISCUSSION...
...Heavy Rainfall Threat Continues into Wednesday Across ECFL...
Current-overnight...Will likely be able to expire the Wind Advisory
for Coastal Volusia and Gale Warning for the adjacent coastal waters
off of the Volusia coast with late evening updates.
WSR-88D fairly quiet south of Orlando this evening with scattered
showers and isolated thunder north of here presently. Local HRRR
model run suggests that overall precipitation chances are on the
decline, but this evening especially along the I-4 corridor some
locally heavy rainfall may still occur.
The tropical area of low pressure is presently located just inland
near St. Augustine this evening. This according to most recent
surface observations, satellite imagery, and radar. While latest
tropical formation chances are up to 70 percent for this system, it
is highly unlikely that any counties in ECFL will be associated with
any upgrades to the system.
Winds ranging from SSW to SE overnight becoming lighter. Overnight
lows in the 70s with humid conditions.
Wednesday...PREVIOUS MODIFIED...What remains of the weak low will be
near or just north of Apalachee bay early Wednesday morning, then
dampen out as it moves NW-NNW by Wed evening. Atlantic high pressure
ridge will reassert its influence in the wake of the low, while
residual high PWAT air, especially across the northern CWA, keeps
rain chances above normal. Given the moisture profile and weakening
steering flow, locally heavy rainfall amounts appear quite likely.
Temps remain near climo... mainly upper 80s for maxes and mid-upper
70s for mins.
&&
.AVIATION...Diminishing shower/isolated storm activity across the I-
4 corridor thru late evening. There will still remain a small threat
overnight for convection, given the very soupy airmass in place.
KXMR evening sounding shows a PWAT of 2.43 inches. Tempo MVFR
remainder of night for TAF sites that do see precipitation. Will
also have to watch for some BKN stratus late overnight/early Wed
morning due to the precipitation that has fallen over the past day.
Have kept in place inherited tempo groups for BKN012-015 at some
sites aft 08Z.
Concern for Wed will be in the afternoon for developing storms with
locally heavy rainfall moving southwest to northeast across the
central peninsula, given the proximity of the low to the north, very
deep moisture in place, and afternoon instability from surface
heating.
&&
.MARINE...Current-overnight...Will likely be able to expire Gale
Warning for next CWF issuance over the north marine legs, while
keeping SCA in place for areas Sebastian Inlet northward to Flagler
Beach. Will likely keep in place cautionary statements from
Sebastian Inlet thru Jupiter Inlet. S/SE winds 20 to 25 kts with
frequent higher gusts over the open Atlc across Advisory areas and
15 to 20 kts southward. Seas generally 4-6 ft near shore and 5-8 ft
Gulf Stream gradually diminishing.
Wed...Will see a gradual decreasing of both winds/seas. Mariners
will have to watch for afternoon shower/storm activity moving off of
the east coast, especially north of Sebastian Inlet.
&&
.MLB Watches/Warnings/Advisories...
FL...Wind Advisory until 10 PM EDT this evening for Coastal Volusia
County.
AM...Small Craft Advisory from 11 PM this evening to 6 AM EDT
Wednesday for Flagler Beach to Volusia-Brevard County Line
0-20 nm-Flagler Beach to Volusia-Brevard County Line 20-60
nm.
Gale Warning until 11 PM EDT this evening for Flagler Beach to
Volusia-Brevard County Line 0-20 nm-Flagler Beach to
Volusia-Brevard County Line 20-60 nm.
Small Craft Advisory until 2 AM EDT Wednesday for Volusia-
Brevard County Line to Sebastian Inlet 0-20 nm-Volusia-
Brevard County Line to Sebastian Inlet 20-60 nm.
&&
$$
Sedlock/Lascody
Area Forecast Discussion
National Weather Service Phoenix AZ
815 PM MST TUE SEP 13 2016
.SYNOPSIS...
A weather disturbance passing through the region this evening will
continue to trigger scattered showers and thunderstorms through this
evening, mainly over the higher terrain of central and eastern
Arizona. A much drier airmass will then envelop the region through
the remainder of the week, and into the upcoming weekend, yielding
widespread dry weather, with temperatures remaining near to slightly
cooler than normal.
&&
.DISCUSSION...
UA data showed atmospheric winds have turned decidedly west and
southwest, and rather strong, as an early season fall storm swept
into the western states just north of Las Vegas. Westerly winds also
brought drier air to the western half of AZ, with a dry line noted
about 40 miles east of Phoenix. East of the dryline a few showers
and thunderstorms continued at 8 pm, mainly over our portions of
southern Gila County but were winding down with nightfall. All
storms in Gila County should end shortly before midnight
followed by clear skies.
Models show the dryline will be stationary just east of Phoenix
tonight through early Wednesday. Modeled soundings for parts of
southern Gila County on Wednesday showed potential C.A.P.E., about
236 j/kg with a convective trigger temp of 80 degrees, however after
2 pm the dry line accelerates east and erodes the existing C.A.P.E.
Clear skies will cover most of the forecast, southeast CA to south
central AZ on Wednesday, followed by afternoon clearing in southern
Gila County. Clear skies are forecast Thursday.
Current forecasts with gradually diminishing shower potential in
southern Gila County this evening looks ok. So are the dry forecasts
for the remainder of the week. No updates needed.
.Previous Discussion...123 PM MST...
Tonight...
latest radar imagery is now showing convective activity beginning to
develop at this hour over the Rim County southward into Gila county,
with some light showers also showing up over northern Pima/extreme
southern Pinal County. These activity is being kicked off by a
shortwave/70kt upper jet max that is now rotating northeastward into
SW and south-central AZ. Although this jet max is generating
considerable mid and high cloudiness over SW and south-central AZ
(which will likely inhibit convective development over the lower
elevations), the latest SPC Mesoscale analysis is showing decent
MLCAPE (500-1000 J/KG) over the higher terrain east of Phoenix.
Thus, have raised pops a bit over Southern Gila County through the
early evening hours, which the HRRR also shows where most convective
activity should occur. Like last night, convective activity should
rapidly diminish after sunset as the atmosphere rapidly stabilizes
due to loss of solar heating and mid-level drying. The main impacts
from any storms that do form will be brief heavy rain and gusty
winds, as well as a chance for some small hail. Storm movement
should be quick enough to limit residence time over any one
location, limiting the the flood threat potential.
Wednesday through Monday...
Medium range models continue to project very little forecast
uncertainty for the latter half of the week with the primary
shortwave trough lifting into the plains, yet weak negative height
anomalies and persistent dry westerly flow lingering through the SW
Conus. This flow pattern will push any appreciable moisture east of
the Continental Divide and well into central Mexico starting
Wednesday afternoon dictating no chance of rainfall throughout the
entire region for at least several days. A deepening low over
Arizona may try to pull moisture back into parts of the forecast
area later in the weekend, however the quicker forward motion to
this wave may only allow some wrap around midlevel moisture into the
far eastern parts of the state. H5 heights will languish in a 582-
584dm range keeping temperatures in an average to slightly below
average range. In fact, with cooler daytime temperatures, an
extremely dry airmass, and clear skies, overnight lows will easily
plummet into the 60s for many lower elevation locations (and even
some 50s in the coolest communities). A definite sign that desert
southwest autumn weather is not that far away.
&&
.AVIATION...
South-Central Arizona Including KPHX, KIWA, and KSDL:
Through 08z Wed, sct clds near 12 thsd agl with bkn cirrus above.
West wind 8 to 12 knots. From 08z Wed to 19z Wed, clear skies.
Southeast wind 5 to 8 knots.
Southeast California/Southwest Arizona including KIPL and KBLH:
THrough 19z Wed, clear skies. West to southwest wind 8 to 12 knots.
Aviation Discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Friday through Tuesday... Temperatures will slowly increase Friday
through Monday. Dry air will be in place with minimum humidities in
the 5 to 20 percent through Saturday and then slightly increasing
Sunday through Tuesday(with the highest humidities over the higher
terrain east of Phoenix). Overnight, fair to good overnight
recoveries are expected. Winds will follow typical diurnal trends
with light winds. No thunderstorms are expected across the forecast
area through Tuesday.
&&
.SPOTTER INFORMATION STATEMENT...
Amateur radio Skywarn net activation is not expected at this time.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...Vasquez/Percha/MO
AVIATION...Vasquez
FIRE WEATHER...Hernandez
Area Forecast Discussion
National Weather Service Amarillo TX
431 AM CDT WED SEP 14 2016
.DISCUSSION...
The forecast for the next several days remains difficult given that
rain chances will be heavily dependent on timing of subtle embedded
shortwaves within southwest flow aloft.
An upper level trough moving towards the Four Corners region will
keep the flow over the Panhandles out of the southwest through
Thursday. Surface observation across the Southern Great Plains show
winds already shifting towards the south early this morning as an
embedded shortwave moves across central New Mexico. The HRRR picks
up on this shortwave fairly well and shows convection over the
Eastern NM Plains spreading into the far western portion of the CWA
through the late morning hours. Once this initial wave passes we will
likely see a lull in activity into the early afternoon hours. The
next round is anticipated during the evening/overnight hours as
another wave and left exit region of an approaching jet streak moves
towards the Panhandles. Assuming some clearing of clouds throughout
the day, mixed-layer CAPE is forecast to reach into the 1000-1500
J/kg with deep layer shear in the 30-35kt range. As such, we could
see isolated strong to marginally severe storms develop if all the
factors line up during this round of storms.
Thursday could see a few lingering showers into the morning hours
before the next in a series of shortwave disturbances moves across
the Panhandles. Forecast models are struggling on handling the
timing of the best rain chances but the general consensus is during
the evening into overnight hours once again. Instability will again
be limited by persistent cloud cover, but if we can break out of the
clouds then we may be able to tap into the forecast 1200-1800 J/kg of
mixed-layer CAPE. Deep layer shear is anticipated to be fairly
limited (roughly 20kt) so a strong storm can`t be ruled out.
Overnight storms will likely linger into Friday morning as models
show another cold front approaching the area. There is very little
consensus between the various solutions on the amount of southward
progression the front will be able to make. Some stall the front
across the northern Texas Panhandle with others sending the front
south of Lubbock by Saturday morning. Have gone with a blend of
solutions which brings the front all the way through for the western
Panhandle but stalls the front across the southeastern Texas
Panhandles. Storms are expected to develop along this front as it
moves southward across the Panhandles.
The weekend continues to have significant differences in the forecast
upper pattern. In general, the trough which is anticipated to bring
our numerous chances for rain is expected to deepen over the weekend.
From this point onward, several possibilities exist for the evolution
of this system. Each model does eventually close the trough off, but
some models push the low center much further south than other. The
more southern of the solutions (ECMFW) sends the low into the
Pacific while the further north position (GFS) would allow for the
closed low to be ingested back into the upper flow. While the further
south position doesn`t seem to have much affect on rain chances over
the weekend, but the further south position could bring us an
extended lull in convective chances early next week. The further
north position would remain rain chances well into next week as it
moves over the Panhandles. Have held rain chances through the end of
this forecast but kept chances low given the uncertainty at this
point.
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 78 61 81 60 80 / 40 50 50 50 60
Beaver OK 77 63 86 63 83 / 30 40 40 50 40
Boise City OK 75 59 83 56 76 / 30 40 20 30 20
Borger TX 78 64 85 64 82 / 40 50 40 50 50
Boys Ranch TX 79 62 84 60 82 / 40 50 40 40 50
Canyon TX 78 61 81 60 80 / 40 50 50 50 60
Clarendon TX 80 62 83 63 81 / 40 40 50 50 70
Dalhart TX 76 58 84 58 80 / 40 50 20 30 30
Guymon OK 76 62 86 60 80 / 30 40 30 40 30
Hereford TX 80 60 82 60 81 / 40 50 50 50 60
Lipscomb TX 79 64 85 64 83 / 30 50 40 50 50
Pampa TX 78 61 84 61 81 / 30 50 40 50 60
Shamrock TX 82 64 84 65 82 / 40 40 50 50 70
Wellington TX 86 66 86 66 85 / 40 30 50 50 70
&&
.AMA Watches/Warnings/Advisories...
TX...None.
OK...None.
&&
$$
11/14
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
319 AM EDT WED SEP 14 2016
.DISCUSSION...
The surface cold front, better described as a surface wind shift
boundary, has pushed through southern MI as of 07Z. Convection fired
along m59 on the trailing elevated portion of the front, mainly
between 850-700mb, as the right entrance region of the upper level
jet caught up to the ribbon of higher theta e dropping through lower
MI. This more concentrated activity is starting to wane in favor of
more scattered showers between I69 and I94. The system will continue
southward through the morning hours, with the HRRR and RAP
suggesting all showers will push southward out of SE MI by about
15Z. They seem to be handling the current activity pretty well so
will lean toward these solutions for this forecast.
Northerly flow in the wake of the front will usher in cooler airmass
through the afternoon hours. Depth of cool air will not be too
great, maybe sfc-800mb, and will not be overly cold with 925mb/850mb
temps holding around 14C/9C respectively through the afternoon. This
should result in highs only in the low 70s today but will also lead
to increasing low level lapse rates as diurnal heating kicks in.
With flow off Lake Huron keeping moisture advection below the
inversion at 800mb, expect some afternoon showers to develop
especially over the Thumb region.
Surface high pressure will build into the region through the day
centering over the eastern Great Lakes by this evening. This should
help clear us out pretty quickly around sunset leading to lows
dipping into the upper 40s. Mid level ridge will then move over
lower MI Wednesday night into Thursday bringing sunny but cooler
weather to end the work week. Little thermal recovery is expected
until Friday when we get back into southerly flow ahead of the next
system. Models have been fairly consistent the last couple runs with
bringing a midlevel closed low over the west coast up through the
northern lakes on Saturday while becoming an open wave. Best chance
of precipitation continues to fall on the Saturday period as a cold
front sweeps through, though showers could enter as early as friday
night. With average high temperatures now in the mid 70s, it appears
we will hover right around that + or - a couple degrees each day
through the end of the forecast.
&&
.MARINE...
Winds will veer to the north and northeast this morning in the wake
of passing cold front. While wind gusts to 20 knots or so can be
expected today over Lake Huron, wave heights over the nearshore
waters appear to remain below small craft advisory criterion and no
headlines are anticipated. After showers and a few thunderstorms
shift south/southeast out of the area this morning, expect marine
weather to remain quiet for the remainder of the week until the next
chance of thunderstorms arrives during the weekend.
&&
.PREV DISCUSSION...
Issued at 1203 AM EDT Wed SEP 14 2016
AVIATION...
Activity has been on the increase again as another burst in forcing
works along the sagging cold front. Given spacing of spells this
particular development appears to have been forced by a possible
gravity wave. Bulk of the model data continues to support a solution
that depicts additional development over the southern half of the
cwa after 06Z. Current trends on radar casts some doubt on
additional development between 08-11Z, however, will exhibit
patience. MVFR cig height have corresponded to a true northerly wind
direction, relying on initial low level cold air advection. Model
data supports only a slow evolution to ceiling heights today before
loss of diurnal heating and dry air advection causes skies to go
clear wed night.
at DTW...Will be dealing with some shower and thunderstorm activity
intially passing north of the terminal. However, still expecting max
of frontal forcing between the 07 and 10Z timeframe.
//DTW Threshold Probabilities...
* High for cigs below 5 kft agl tonight.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
DISCUSSION...DRK
MARINE.......DG
AVIATION.....DG
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Grand Junction CO
404 AM MDT WED SEP 14 2016
.SHORT TERM...(Tonight through Thursday night)
Issued at 335 AM MDT Wed Sep 14 2016
Satellite imagery tells a lot of the story this morning. A nice
fountain of uplift derived from divergence aloft and the nose and
left exit region of a 90 kt 300 mb jet stream maxima all show up
nicely on wv and ir satellite over northeast Utah. Moderate
thunderstorms will continue over that area until about 15z when it
all lifts to the north after barely affecting extreme northeast
Moffat county in Colorado.
A SW to NE swath of eastern Utah and northwest and central CO
will be beneath a dry slot for much of the day, though surface
heating should help produce isolated to scattered showers and
thunderstorms mainly over the mountains. The cloud shield
associated with the southern jetstream is pushing off to the east
faster than the NAM and GFS expected, with the HRRR having what
seems to be the better solution. It calls for isolated to
scattered thunderstorms, mainly over the central and southwest CO
mountains this afternoon and evening.
As the upper trough passes over the northern Rockies tonight
through Thursday night, some precipitations skirts the northern CO
border, but the rest of the area should be dry with clearing
skies.
.LONG TERM...(Friday through Wednesday)
Issued at 335 AM MDT Wed Sep 14 2016
Friday through the weekend should dry with a weak closed low
developing over the SW U.S. and west to northwest flow aloft over
the forecast area. Residual moisture and surface heating should
help isolated storms to form over the mountains of the Continental
Divide.
The southwest trough will gradual move over the area Monday and
Tuesday, while another similar trough develops over the SW U.S.
Wednesday. The forecast area should be dry Tue and Wed.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 335 AM MDT Wed Sep 14 2016
Scattered moderate thunderstorms will affect northeast Utah, north
of kvel, and extreme northwest Colorado this morning, then
isolated to scattered showers and thunderstorms will develop over
the rest of the forecast area this afternoon and evening. VFR
conditions should prevail at all the TAF sites, but there is a
small chance of cigs to ILS breakpoints is a stronger cell travels
over on these airports.
&&
.GJT Watches/Warnings/Advisories...
CO...None.
UT...None.
&&
$$
SHORT TERM...CC
LONG TERM...CC
AVIATION...CC
Area Forecast Discussion
National Weather Service Grand Rapids MI
328 AM EDT WED SEP 14 2016
LATEST UPDATE...
Synopsis/Short Term/Long Term/Marine
.SYNOPSIS...
Issued at 327 AM EDT Wed Sep 14 2016
Showers are possible into mid morning then skies will clear as
cooler and drier air move into the area thanks to a large high
pressure system that will move overhead tonight then move east of
the area Thursday. The next storm system will move across the area
Friday night into Saturday with showers and isolated thunderstorms.
Locally heavy rainfall is possible. Temperatures will be near
normal today and Friday, but above normal Saturday and Sunday.
&&
.SHORT TERM...(Today through Friday)
Issued at 327 AM EDT Wed Sep 14 2016
The main question is will there be more showers over the CWA this
morning as the back edge of the polar jet moves across the area.
Beyond that there is a question as to how cold it can get tonight
as skies should be clear and winds light.
The 90 knot jet core`s back edge moves across Lower Michigan
during the mid morning hours of today. There is an area of jet
lift associate with that. Given all the showers over WI at 3 AM it
would seem reasonable that what the HRRR has been showing will
come true... that is an area of showers will cross most of the CWA
in the 7am to 9am time frame.
After that little question skies will clear this afternoon and
tonight with the surface high overhead winds should also be light.
This could be one of the colder nights of the season so far. It
would not be out of the question some locations in our NE CWA may
see lows in the mid to upper 30s (Leota).
The next system will not bring enough moisture into the area to
bring showers into our CWA until after dark on Friday so not much
of an issue there.
.LONG TERM...(Friday night through Tuesday)
Issued at 327 AM EDT Wed Sep 14 2016
A low pressure system will move slowly east across the northern
Great Lakes region Friday night through Saturday and bring showers
and perhaps some thunderstorms. The convective threat is marginal
due primarily to weak instability.
The system will depart our region on Sunday but a few lingering
showers are still possible as an upper level trough moves through.
Medium range guidance trends indicate that temperatures will
continue to average around 10 degrees above normal through the long
range forecast period.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1144 PM EDT Tue Sep 13 2016
Scattered thunderstorms could affect our far eastern terminals
(KLAN and KJXN) during the next couple of hours. The thunderstorms
developed rapidly during the past half an hour and will drift east
and bring potential for occasional lightning and brief heavy rain.
Conditions will be vfr overnight at most of the terminals but
brief reductions into the MVFR flight category are possible due to
low clouds and the storms in the vicinity of KLAN and KJXN. Vfr
conditions will continue through the day Wednesday with nothing
more than development of some sct fair wx cumulus by around midday
with cloud bases at around 4 kft agl. Skies will become mostly
clear at all the terminals Wednesday evening.
&&
.MARINE...
Issued at 327 AM EDT Wed Sep 14 2016
Surface high pressure should mean light winds and clearing skies
to I see no issues for the near shore until the next frontal
system moves into the area Friday night.
&&
.HYDROLOGY...
Issued at 326 PM EDT Tue Sep 13 2016
Mid-level frontogenesis near South Haven to Lansing Tuesday night in
a convectively unstable layer may yield a several hour period of
moderate rainfall. Basin average amounts around a quarter inch are
most likely but WPC does have the area south of Holland-Alma in a
marginal risk of rainfall exceeding flash flood guidance amounts. As
for rivers in the Grand and Kalamazoo basins, most are near to only
moderately above normal for mid-September, and most basins except
for the some of the headwaters should be capable of handling a few
hours of moderate rainfall.
&&
.GRR Watches/Warnings/Advisories...
MI...None.
LM...None.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...Laurens
AVIATION...Laurens
HYDROLOGY...CAS
MARINE...WDM
Area Forecast Discussion
National Weather Service Lincoln IL
306 AM CDT WED SEP 14 2016
.SHORT TERM...(Today and tonight)
ISSUED AT 305 AM CDT Wed Sep 14 2016
Latest surface analysis indicating a weak cool front just south of
the Interstate 72 corridor with a wave of low pressure over southern
Missouri tracking east-northeast along the boundary. Most of the
showers and thunderstorms that have been occurring across our area
were north of the frontal boundary with very little precip to its
south. Much drier air was located well to the north of the cool
front early this morning with surface dew points in the mid to upper
40s from northwest Iowa northeast into north central Wisconsin.
Meanwhile, further south, dew points in our area were generally
holding in the low to mid 60s.
The main forecast concern in the short term will be coverage of
showers and thunderstorms in our area today and their affect on
afternoon temperatures. Models continue to suggest the main push
of showers and storms today will be along and especially north
of the front, that will not move a great deal this morning until
the weak area of low pressure shifts off to our east early this
afternoon. Until that happens, we can expect the scattered showers
and isolated thunderstorms to continue across the area with the
greater coverage occurring north of the boundary. Once the wave
shifts off to our east early this afternoon, the front will shift
south with the potential for new convection to develop along the
boundary as the atmosphere over southeast Illinois will see moderate
instability with Most Unstable Capes from 2500-3000 J/KG and 0-6 Km
Bulk Shear values of 25-30 kts. However, mid level lapse rates don`t
look very impressive this afternoon in our southeast counties, so a
few storms may produce some gusty winds and brief heavy rainfall,
but the threat for any organized severe storms looks minimal at this
time. The cool front should push well south of our area by late this
afternoon or early this evening taking the rain threat to the south
as well, with weak high pressure building south into the lower Great
Lakes tonight.
With the extensive cloud cover over the northern half of the
forecast area today, coupled with a light north to northeast flow,
temperatures this afternoon will be in the 75 to 80 degree range
while over southeast Illinois, there will a bit more sunshine which
should help afternoon temperatures push into the mid and possibly
upper 80s.
&&
.LONG TERM...(Thursday through Tuesday)
ISSUED AT 305 AM CDT Wed Sep 14 2016
High pressure drifting east across the Great Lakes to provide a dry
easterly flow early Thursday, so the precipitation shield developing
to our west will be a bit slow to arrive. Have limited any daytime
PoP`s to the far southwest CWA during the afternoon. Both the GFS
and ECMWF project a good part of the evening to be dry as well, with
the main focus overnight into Friday ahead of the cold front. The
front is still progged to slow to a crawl for a time on Saturday, as
the remnant wave from the upper low passes across the Great Lakes.
Thus, it will likely take until late Saturday evening before the
bulk of the showers and thunderstorms exit the forecast area.
Longer range forecast remains problematic. Longwave trough deepening
over the Desert Southwest this weekend may get cut off from the
overall flow across the northern half of the CONUS. Timing of the
waves in the northern steering flow is significantly different
between the GFS and ECMWF, with the former model bringing a cold
front and associated showers/storms through by midweek, while the
latter largely keeps us dry through the first few days of the week.
The forecast for the early part of the week will favor the dry
solution due to the poor model consensus.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1148 PM CDT Tue Sep 13 2016
The cold front appears to have progressed south of the terminal
sites as of 04z. Satellite images indicate a couple of shortwaves
in northern and eastern Missouri will travel east along the front
across central Illinois the rest of the night and into Wed
morning. The latest RAP model indicates a wave of precip will
continue through 13-14z primarily between I-70 and Peoria, then a
break is possible until additional storms develop in the afternoon
mainly south of a line from Taylorville to Mattoon. The latest
HRRR continues to keep the focus mainly N of I-72.
Have adjusted precip to end it by mid morning. With no afternoon
precip included as it could all remain south of the terminal
sites. Thunderstorms will be isolated, as instability remains
weak the rest of the night. IFR ceilings will be possible in the
post-frontal air mass, per HRRR output. IFR visibility in rain
and fog will be possible as well in the hours surrounding sunrise.
Conditions will gradually improve to MVFR behind the front
Wed morning, with some clearing even possible Wed evening. Winds
will are in the process of shifting to the W-NW behind the front.
Wind directions will become N to NE tomorrow, with sustained
speeds generally remaining below 10kt.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Smith
LONG TERM...Geelhart
AVIATION...Shimon
Area Forecast Discussion
National Weather Service Omaha/Valley NE
353 AM CDT WED SEP 14 2016
.SHORT TERM...(today through Friday)
Issued at 353 AM CDT WED SEP 14 2016
Latest water vapor imagery and RAP analysis shows large mid-upper
level low centered over the Great Basin. Meanwhile, a large area
of surface high pressure extended from the Dakotas into the
Central Plains with the associated surface ridge axis currently to
our west. A ribbon of thunderstorms continues to move northeast
over northeast Kansas, extreme southeastern Nebraska and northwest
Missouri within an area of elevated instability. Most recent runs
of the CAMs show this area diminishing by sunrise so will hold on
to a small pop in our south through the morning. An extensive
area of low clouds/drizzle remains anchored over the area with
some clearing across far northeast Nebraska. Cloudy conditions
will likely continue through much of the day with patchy drizzle
confined to the southern CWA.
The above mentioned surface ridge axis will slide east of the area
tonight allowing warm southerly return flow to increase. Strong
isentropic upglide in the 300-305K layer should promote
widespread showers and isolated thunderstorms across central
Nebraska and Kansas late tonight and spread east throughout the
morning. In addition, previous mentioned Great Basin mid-upper
level low will be moving into the western Dakotas by this time, allowing
the associated trough axis to move over the High Plains with lead
shortwave energy ejecting out ahead of it. The associated surface
low is forecast to move across the Dakotas with a southward
extending cold front. Uncertainty remains on coverage of showers
and thunderstorms late Thursday morning and how much
destabilization can occur toward peak heating ahead of the
approaching cold front. Sufficient deep layer shear will be
present along with steepening mid level lapse rates as upper
impulse moves overhead. Strong to severe storms are not out of the
question late Thursday afternoon across central Nebraska and into
our western counties which could then spread east across the
entire forecast area Thursday night as the cold front slides east
overnight.
Quiet conditions are expected behind the front Friday but a few
lingering showers are possible in our eastern areas.
.LONG TERM...(Friday night through Tuesday)
Issued at 353 AM CDT WED SEP 14 2016
Relatively quiet conditions are expected Friday night through the
weekend as a surface high pressure moves overhead. Showers and
thunderstorms return to the forecast early next work week in warm
air advection regime. Temperatures in the extended should remain
above normal.
&&
.AVIATION...(06Z TAFS for KOFK...KLNK and KOMA.)
Issued at 1145 PM CDT TUE SEP 13 2016
VFR conditions at KOFK should continue much of the night with at
least temporary MVFR ceilings possible toward sunrise. For KOMA
and KLNK...current MVFR ceilings are likely to continue but with
IFR ceilings and some fog and patchy drizzle possible late
tonight. North winds will turn to east and then southeast through
the period. Some TSRA possible toward the end of the TAF period
but will not include at this time.
&&
.OAX Watches/Warnings/Advisories...
NE...None.
IA...None.
&&
$$
SHORT TERM...Kern
LONG TERM...Kern
AVIATION...Miller
Area Forecast Discussion
National Weather Service Paducah KY
309 AM CDT WED SEP 14 2016
.SHORT TERM...(Today through Friday)
Issued at 300 AM CDT Wed Sep 14 2016
Quasi stationary surface boundary in the vicinity will wobble
across the area and serve as a potential mechanism of isolated
shower or storm development during the heat of the day today. The
GFS is already overdone on developing pcpn on this boundary, and
it`s likely the HRRR is more in sync with its very spotty
coverage.
By tonight, the boundary has made passage/ceased to be a player as
the upper ridge arcs across the mid Mississippi river valley,
providing a brief pop respite save for a transitioning slight
chance mention we`ve been carrying in the SEMO Ozarks.
We still see height falls in the High plains and backed swlys
aloft driving Pacific moisture this way, with Pops incoming again
during the daytime Thursday, in advance of this next approaching
system. While pops temporarily wane at night, they pick up again
Friday in more earnest, with additional eastward coverage, as the
aforementioned system works its way toward the Great Lakes and
drags its cold front closer to the mid Mississippi river valley
and our neck of the woods.
Summer like temps and humidities will continue until this end of
week front makes passage, so upper end 80s/around 90 for highs
and upper end 60s/around 70 for lows look to be the rule.
.LONG TERM...(Friday night through Tuesday)
Issued at 300 AM CDT Wed Sep 14 2016
Models are in good agreement through the weekend. A front will be a
little slower to approach the region on Friday with steadily
increasing pops into Saturday. Both models are now slower to move
the front through and pops linger into Monday. The GFS still has a
stronger high behind the front that clears everything out by midday
Monday. The ECMWF is slower and not as strong with the subsequent
high and dry air. The forcast leans toward the GFS. Both models
quickly return moisture to our west on the west side of the high by
Tuesday but dry weather should prevail for this forecast area
through midweek.
Temperatures should be near or slightly above normal through the
period.
&&
.AVIATION...
Issued at 300 AM CDT Wed Sep 14 2016
Mid cloud cover was minimizing fog to patchy MVFR at this writing,
though temporary further restrictions are possible. Given the
proximity of a nearby frontal boundary, there may be some
isolated shower and storm development, particularly during the
daylight hours, but chances are too low to include in the
Terminal mention just yet.
&&
.PAH Watches/Warnings/Advisories...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
Area Forecast Discussion
National Weather Service Raleigh NC
315 AM EDT WED SEP 14 2016
.SYNOPSIS...
Tropical cyclone Julia is forecast to weaken and drift very slowly
north through Thursday over southeast GA. Otherwise, high pressure
over NC will drift offshore ahead of a weak and moisture-starved
cold front. This front will move south across VA and NC late tonight
and Thursday.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 315 AM Wednesday...
Tropical Storm Julia is expected to stay well south of our region as
strong ridging persists today. However, there may be just enough
moisture convergence with the sea breeze and weakening bands of
convection associated with Julia to include a 20-30 POP this
afternoon in the SE Coastal Plain. The latest HRRR and other convection
allowing models indicate the potential for a band or two of convection
to potentially move into the FAY to GSB areas late today into the
evening.
Otherwise, dry, hot, and mostly sunny today. Expect increasing cloudiness
later today especially in the east and south. Highs generally in the
upper 80s to lower 90s again.
The backdoor cold front to the north is expected to approach
central NC tonight as Julia remains well to our south. Dry
conditions will continue with the exception of the chance of showers
in the SE associated with Julia`s circulation and moisture
convergence that touches the SE zones. Lows tonight with partly to
mostly cloudy skies in the upper 60s to lower 70s.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 315 AM Wednesday...
Just a slight uptick in POP for scattered showers and thunderstorms,
mainly in the east and south (Coastal Plain). This is where some
moisture convergence associated with the weakening remnants of Julia
is projected by most models. However, it is still uncertain how much
of the deep tropical moisture can be pulled up into our region. It is
near the NC/SC border region (and this appears to be the only area that
has a decent shot and this occurrence). Julia is forecast to remain
too far south for now. Otherwise, the weak cold front will offer only
an isolated threat for a shower elsewhere. We will keep POP in the 40-50
range SE, to less than 20 percent NW. QPF among the models has increased
in the far SE (Sampson, Wayne, Cumberland) but still remains questionable.
We will carry 0.25 to 0.50 in the SE. This may need to be bumped up in that
region in later forecasts if trends continue.
Otherwise, expect variably to mostly cloudy skies for the Piedmont and
northern Coastal Plain. Highs cool back into the 80s. Lows in the lower to
mid 60s, except near 70 SE, with a chance of showers and isolated thunderstorms
lingering in the SE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 225 AM Wednesday...
Low confidence persists during the long term forecast period in
assoc/w a complex synoptic pattern expected to evolve over the CONUS
this weekend into early next week. Additionally, forecast confidence
at the beginning of the long term period is lower than average due
to significant uncertainty in the evolution of newly formed Tropical
Cyclone Julia along the northern FL coast. In general, a shortwave
ridge will prevail over the Mid-Atlantic/Carolinas on Friday, with a
sfc ridge axis extending SW into the region from high pressure
offshore the Mid-Atlantic/New England coast. Surface ridging will
weaken and give way to weak pre-frontal troughing this weekend and
early next week. At this time, expect highs near normal early in the
period, becoming near-normal or slightly above normal this weekend
and early next week. However, with low confidence in the timing/
coverage/location of precipitation throughout the period, this may
be optimistic. -Vincent
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
As of 145 AM Wednesday...
24 Hour TAF Period: VFR conditions remain likely for the majority of
the 24 hour period as high pressure remains across the area. There
is a low probability of MVFR ground fog at KRDU and KFAY around
sunrise. There is a moderate probability of MVFR, and possibly IFR
fog between 09Z-13Z at KRWI.
Outlook: A dry cold front will move through the area on Thursday.
Outside of some pre-dawn stratus or fog at KRWI and KFAY, VFR
conditions are expected through Sunday.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Badgett
NEAR TERM...Badgett
SHORT TERM...Badgett
LONG TERM...Vincent
AVIATION...Badgett
Area Forecast Discussion
National Weather Service Amarillo TX
628 AM CDT WED SEP 14 2016
.AVIATION...
12Z TAF Cycle
Low cloudiness and patchy fog will result in VLIFR to IFR conditions
until around 13Z to 15Z today at the Amarillo TAF site. Showers and
thunderstorms will move east and northeast and should affect the
Amarillo and Dalhart TAF sites between about 13Z and 18Z today with
MVFR to IFR conditions. The Dalhart and Amarillo TAF sites should see
the MVFR conditions become VFR after 18Z to 20Z today. MVFR
conditions at the Guymon TAF site will become VFR after 20Z today.
Northeast to east winds 5 to 10 knots or less will become southeast
to south after 18Z at all three TAF sites 10 to 15 knots which will
continue through 12Z Thursday.
Schneider
&&
.PREV DISCUSSION... /Issued 619 AM CDT WED SEP 14 2016/
UPDATE...
Advection fog has moved into the eastern part of Amarillo this
morning to drop visibilities down to a quarter mile. Expect this fog
to persist through the morning commute and have also issued a
localized Dense Fog Advisory until 9 AM. Updated text products have
already been issued.
PREV DISCUSSION... /Issued 431 AM CDT WED SEP 14 2016/
DISCUSSION...
The forecast for the next several days remains difficult given that
rain chances will be heavily dependent on timing of subtle embedded
shortwaves within southwest flow aloft.
An upper level trough moving towards the Four Corners region will
keep the flow over the Panhandles out of the southwest through
Thursday. Surface observation across the Southern Great Plains show
winds already shifting towards the south early this morning as an
embedded shortwave moves across central New Mexico. The HRRR picks
up on this shortwave fairly well and shows convection over the
Eastern NM Plains spreading into the far western portion of the CWA
through the late morning hours. Once this initial wave passes we will
likely see a lull in activity into the early afternoon hours. The
next round is anticipated during the evening/overnight hours as
another wave and left exit region of an approaching jet streak moves
towards the Panhandles. Assuming some clearing of clouds throughout
the day, mixed-layer CAPE is forecast to reach into the 1000-1500
J/kg with deep layer shear in the 30-35kt range. As such, we could
see isolated strong to marginally severe storms develop if all the
factors line up during this round of storms.
Thursday could see a few lingering showers into the morning hours
before the next in a series of shortwave disturbances moves across
the Panhandles. Forecast models are struggling on handling the
timing of the best rain chances but the general consensus is during
the evening into overnight hours once again. Instability will again
be limited by persistent cloud cover, but if we can break out of the
clouds then we may be able to tap into the forecast 1200-1800 J/kg of
mixed-layer CAPE. Deep layer shear is anticipated to be fairly
limited (roughly 20kt) so a strong storm can`t be ruled out.
Overnight storms will likely linger into Friday morning as models
show another cold front approaching the area. There is very little
consensus between the various solutions on the amount of southward
progression the front will be able to make. Some stall the front
across the northern Texas Panhandle with others sending the front
south of Lubbock by Saturday morning. Have gone with a blend of
solutions which brings the front all the way through for the western
Panhandle but stalls the front across the southeastern Texas
Panhandles. Storms are expected to develop along this front as it
moves southward across the Panhandles.
The weekend continues to have significant differences in the forecast
upper pattern. In general, the trough which is anticipated to bring
our numerous chances for rain is expected to deepen over the weekend.
From this point onward, several possibilities exist for the evolution
of this system. Each model does eventually close the trough off, but
some models push the low center much further south than other. The
more southern of the solutions (ECMFW) sends the low into the
Pacific while the further north position (GFS) would allow for the
closed low to be ingested back into the upper flow. While the further
south position doesn`t seem to have much affect on rain chances over
the weekend, but the further south position could bring us an
extended lull in convective chances early next week. The further
north position would remain rain chances well into next week as it
moves over the Panhandles. Have held rain chances through the end of
this forecast but kept chances low given the uncertainty at this
point.
&&
.AMA Watches/Warnings/Advisories...
TX...Dense Fog Advisory until 9 AM CDT this morning for the following
zones: Potter...Randall.
OK...None.
&&
$$
11/14
Area Forecast Discussion
National Weather Service Bismarck ND
945 AM CDT Wed Sep 14 2016
.UPDATE...
Issued at 945 AM CDT Wed Sep 14 2016
VFR cloud deck continues to lift north across central ND. Models
have no clue so based sky cover forecast on latest sat imagery and
latest trends.
No other major updates for this forecast issuance. Frost advisory
expired earlier on time.
UPDATE Issued at 625 AM CDT Wed Sep 14 2016
Models are having a hard time with the low VFR cloud deck over
southwest and south central ND. Last few iterations of the HRRR
Initialize the deck but dissipate it quickly. Also hard to find
any other guidance that depicts this correctly. GLAMP guidance in
the ballpark so started with this and manually increased sky
cover southwest and south central and tracked it northeast a few
hours before dissipating later this morning with increased
insolation. Cloud layer is pushing into the southern fringe of the
Frost Advisory but with just a little more than an hour to go, see
no need to adjust at this time.
&&
.SHORT TERM...(Today and tonight)
Issued at 324 AM CDT Wed Sep 14 2016
Today is a transition period and will be quiet with temperatures
about 10 degrees warmer than yesterday. We will see clear skies
and southerly winds ahead of an approaching storm system. Tonight
lee cyclogenesis will be in full force and a surface low will
deepen and push into southwestern North Dakota. This will be the
main focus for weather over the next several days.
.LONG TERM...(Thursday through Tuesday)
Issued at 324 AM CDT Wed Sep 14 2016
A deep Mountain West trough will swing across the plains Thursday
and Friday. A deep low will become nearly vertically stacked over
North Dakota. This will bring widespread showers and thunderstorms
and windy conditions to the area. With precipitable water over an
inch and sustained lift over the area for 24 hours, widespread
rainfall around one inch (or greater in some locations) appears
rather likely. Stronger thunderstorms with hail and gusty winds
seem possible Thursday afternoon and evening as models are
indicating enough instability and shear to maintain rotating
updrafts.
This system will move out by Friday night and make way for a
beautiful weekend. Temperatures in the 70s and 80s and dry
conditions are expected for the weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 945 AM CDT Wed Sep 14 2016
Low VFR cloud deck covers KMOT and KJMS and continues to advect
north and east. Expect this area of BKN-OVC clouds to dissipate
later this morning. Mostly clear through the remainder of the day
with increasing mid and high level clouds tonight. Showers move
into the southwest after midnight, then expand north and east
towards 12Z with deteriorating conditions for Thursday.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...TWH
Area Forecast Discussion
National Weather Service Denver/Boulder CO
501 AM MDT WED SEP 14 2016
.SHORT TERM...(Today and tonight)
Issued at 501 AM MDT Wed Sep 14 2016
Stratus has formed across most of the plains, but the higher
clouds moving over slowed the development. Very weak Denver
cyclone wind pattern with stratus on the north side of it from
Boulder into Weld county. Also some hints of a little fog, but
mainly along the Cheyenne Ridge. Still expecting stratus to fill
in more and spread south into Denver, but confidence on how far
south it gets is low. More widespread fog is looking unlikely with
the higher cloud deck.
Lift generating the current higher clouds should pass eastward
this morning. There are some showers well south of our area, but
it does not appear there will be much over northern Colorado, so I
lowered PoPs a bit this morning. There is a little cooling aloft
behind this wave, and additional convection should develop over
the mountains by early afternoon and move eastward. It looks like
this will become the main trough axis, and this period should be
the best chance of rain. CAPEs will not be that high though, and
it should be too cool for surface-based convection on the plains.
HRRR shows a line of storms moving off the mountains with the
trough axis in the early afternoon. Other models have a variety of
solutions hanging on the unresolved details. Other possible areas
of focus would be the convergence on the Palmer Divide and the
edge of better moisture with storms moving from Elbert county
toward Washington county, and on the north edge of the dry slot
this evening, from the northern mountains across the Cheyenne
Ridge area. For the most part, whatever we get should be weak as
CAPEs will generally be under 800 J/kg. Exception may be the
Palmer Divide stuff which could have the right combination of sun,
heat and moisture south of a Colorado Springs to Akron line. Main
threat from that activity is probably marginally severe hail. Also
could be some gusty winds in stuff moving off the mountains, but
just a small chance of it being severe.
For tonight drier air aloft and subsidence moves in. There is a
chance of some stratus redeveloping on the plains as the low level
flow remains southerly. Probably a bit better mixed and drier than
this morning though. I lowered temps on the plains today, and went
a bit cooler in the mountains tonight.
.LONG TERM...(Thursday through Tuesday)
Issued at 501 AM MDT Wed Sep 14 2016
On Thursday...the upper level trough of low pressure will be moving
across Colorado...with the upper low center across the northern
Rockies and Great Plains States. As the trough passes...drier air
from the west will filter into Colorado...with some downward forcing
moving across the region. However...there will be still be enough
instability and moisture around to produce isolated high based
afternoon and evening showers and thunderstorms. The models are
showing a weak cool front moving across northeastern Colorado by
late afternoon. This front may help keep the focus of shower and
thunderstorm activity over the Palmer Divide.
Friday and Saturday...the upper trough elongates with a couple of
upper level disturbances moving across north central and
northeastern Colorado. These disturbances combined with some
subtropical moisture and daytime heating should result in isolated
to scattered showers and thunderstorms across the the
mountains...Palmer Divide...foothills and adjacent Plains.
Some weak upslope flow should allow the best precipitation chances
to be from the eastern slopes of the mountains across the southern
foothills and Palmer Divide. Friday should be the coolest day of the
week...with the possibility of some morning low clouds and fog on
the plains.
Warmer and drier weather is expected Sunday through Tuesday as upper
level high pressure tries to build over the state and drier air
moves into the area from the west.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 501 AM MDT Wed Sep 14 2016
Still waiting to see if areas of low clouds north of Denver will
spread southward impacting KDEN. There does not appear to be much
fog, so the impact will likely be several hours of MVFR ceilings.
The low clouds will likely remain north of KAPA. For this
afternoon and evening VFR conditions are expected with scattered
thunderstorms that could produce a couple of wind shifts with
speeds up to 30 knots.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
SHORT TERM...Gimmestad
LONG TERM...Kalina
AVIATION...Gimmestad
Area Forecast Discussion
National Weather Service State College PA
1033 AM EDT WED SEP 14 2016
.SYNOPSIS...
A weak cold front will sag south through the region later today. High
pressure will bring dry weather and low humidity for Thursday and
Friday...followed by another cold front late Saturday or early
Sunday. Temperatures will slip back to near normal once again
behind the front.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The cold front as of mid morning extends from northeastern NY
state down into NW Pa and central Ohio. The clouds and showers are
mainly along and behind the front giving an anafront
characteristic to the system.
The cold front will slide southeast through central PA during the
mid to late afternoon hours...and the Lower Susq Valley early this
evening.
Much of the day will likely stay dry across our SE zones, while
showers and a few isolated thunderstorms affect the northern and
west-central mountains into the afternoon hours (mainly on the
cool side of the front).
The HRRR and ARW/NMM NAM cores show the showers dissipating as
they enter the central mountains this afternoon so prospects for a
widespread beneficial rainfall look dim. Forecast Basin Average
QPF (based on a forecast/consensus of operational models, and ENS
guidance) through this evening will almost certainly be under 0.25
inch in most places, and 0.10 or less generally across the SE half
of the state.
Max temps will reach the lower 70s across the far NW to near 80
along the I-99/Route 220 corridor from Altoona up through State
College and Williamsport, to the mid and upper 80s in the SE
where skies will stay mostly sunny into the afternoon hours.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
For tonight...1026 mb sfc high will build from the Glakes Region
to Southern Ontario...helping to push drier and cooler air south
into our forecast area.
A few brief/isolated showers could be roaming across the
southeast half of the CWA this evening...just in the wake of the
cfropa.
PWATs will dip to around 0.5 inch along the PA/MD border by
midnight, but linger between 1-1.25 inches across southern PA
through the night tonight. Look for clearing skies across the
north tonight (allowing temps to dip to chilly readings in the mid
to upper 40s)...but lingering bkn to overcast Strato and Alto Cu
clouds over Southern PA will keep mins in the 50s.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
The long term looks to feature a shortwave trough passage early
in the period followed by a slow resurgence of the eastern US
upper ridge.
A surface high will build out of the Great Lakes for the Thursday-
Friday timeframe bringing a return of dry conditions with mild
days and refreshingly cool nights...thanks to low PWAT air across
much of the region (except for the southern tier, where PWATs will
stay around 1 inch through this 48 hour period.
The upper ridge is forecast to flatten a bit by this coming weekend
paving the way for another weak cold front to bring a chance of
numerous showers and isolated TSRA for Saturday afternoon (NW PA)
and late Sat-Sunday across Central and SERN PA. The small
amplitude of the parent shortwave argues against significant
widespread rain which we could very much use.
The upper ridge pops back in for early next week bringing more dry
and pleasant weather for the last days of celestial summer.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
Low clouds along and just behind the cold front will sag south
into the northern portions of the flying area as the front also
sags south.
The front will slide into central and southern portions of the
region by mid/late afternoon with brief localized reductions
possible - but most terminals will remain VFR.
High pressure will return for Thursday and Friday.
Outlook...
Thu-Fri...Local morning fog otherwise no sig wx.
Sat...Likely shra/tsra west. Scattered impacts central.
Sun...Scattered showers. Reductions poss NW half.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte/Lambert
NEAR TERM...La Corte/Lambert
SHORT TERM...Lambert
LONG TERM...La Corte/Lambert
AVIATION...La Corte/RXR
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1047 AM EDT WED SEP 14 2016
.UPDATE...
The light radar returns over Se Mi this morning are tied to a
remnant mid level front. This front will only slowly inch its way
south toward the Ohio border today. The mid level frontal
circulation will however further weaken as it pushes south. While
a few lingering light showers/sprinkles will remain possible
across Lenawee/Monroe counties over the next couple of hours, the
weakening mid level forcing suggests little support for additional
showers out of the mid cloud deck farther north. Ongoing shallow
cold air advection has led to the development of a broken strato
cu field off Lake Huron. These clouds will continue to expand into
Se Mi under northerly flow off the lake. The moisture flux off the
lake may support an isolated -shra/sprinkle across the thumb
today, with a limiting factor for greater coverage being rather
shallow convective cloud depths. Overall, the going forecast looks
in good shape. An update will be issued mainly to refine timing of
precip trends.
&&
.PREV DISCUSSION...
Issued at 625 AM EDT Wed SEP 14 2016
AVIATION...
Band of post-frontal MVFR stratus has been very unimpressive early
this morning. Given trends over the past 6 hours, will adjust the
ceiling forecast to limit period of MVFR this morning (and focus
mainly I-94) with main BKN-OVC layers in the 5-10kft area as upper
trough axis settles into area. A few sprinkles cannot be ruled out
with this feature, but, again, CIG/VSBY conditions should not be
affected much. Skies are expected to clear 20z-00z and remain so
tonight as high pressure builds into area.
For DTW...Will tentatively maintain several hours of MVFR cigs, but
would not be surprised to see current band of stratus to sink south
of terminal as forecast begins. Expect NNE flow to approach 10 kts
at times today before building high pressure weakens the pressure
gradient late today into tonight.
//DTW Threshold Probabilities...
* Low for cigs below 5 kft agl through 14z this morning.
PREV DISCUSSION...
Issued at 319 AM EDT Wed SEP 14 2016
DISCUSSION...
The surface cold front, better described as a surface wind shift
boundary, has pushed through southern MI as of 07Z. Convection fired
along m59 on the trailing elevated portion of the front, mainly
between 850-700mb, as the right entrance region of the upper level
jet caught up to the ribbon of higher theta e dropping through lower
MI. This more concentrated activity is starting to wane in favor of
more scattered showers between I69 and I94. The system will continue
southward through the morning hours, with the HRRR and RAP
suggesting all showers will push southward out of SE MI by about
15Z. They seem to be handling the current activity pretty well so
will lean toward these solutions for this forecast.
Northerly flow in the wake of the front will usher in cooler airmass
through the afternoon hours. Depth of cool air will not be too
great, maybe sfc-800mb, and will not be overly cold with 925mb/850mb
temps holding around 14C/9C respectively through the afternoon. This
should result in highs only in the low 70s today but will also lead
to increasing low level lapse rates as diurnal heating kicks in.
With flow off Lake Huron keeping moisture advection below the
inversion at 800mb, expect some afternoon showers to develop
especially over the Thumb region.
Surface high pressure will build into the region through the day
centering over the eastern Great Lakes by this evening. This should
help clear us out pretty quickly around sunset leading to lows
dipping into the upper 40s. Mid level ridge will then move over
lower MI Wednesday night into Thursday bringing sunny but cooler
weather to end the work week. Little thermal recovery is expected
until Friday when we get back into southerly flow ahead of the next
system. Models have been fairly consistent the last couple runs with
bringing a midlevel closed low over the west coast up through the
northern lakes on Saturday while becoming an open wave. Best chance
of precipitation continues to fall on the Saturday period as a cold
front sweeps through, though showers could enter as early as friday
night. With average high temperatures now in the mid 70s, it appears
we will hover right around that + or - a couple degrees each day
through the end of the forecast.
MARINE...
Winds will veer to the north and northeast this morning in the wake
of passing cold front. While wind gusts to 20 knots or so can be
expected today over Lake Huron, wave heights over the nearshore
waters appear to remain below small craft advisory criterion and no
headlines are anticipated. After showers and a few thunderstorms
shift south/southeast out of the area this morning, expect marine
weather to remain quiet for the remainder of the week until the next
chance of thunderstorms arrives during the weekend.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
UPDATE.......SC
AVIATION.....99
DISCUSSION...DRK
MARINE.......DG
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Grand Rapids MI
736 AM EDT WED SEP 14 2016
LATEST UPDATE...
Aviation
.SYNOPSIS...
Issued at 327 AM EDT Wed Sep 14 2016
Showers are possible into mid morning then skies will clear as
cooler and drier air move into the area thanks to a large high
pressure system that will move overhead tonight then move east of
the area Thursday. The next storm system will move across the area
Friday night into Saturday with showers and isolated thunderstorms.
Locally heavy rainfall is possible. Temperatures will be near
normal today and Friday, but above normal Saturday and Sunday.
&&
.SHORT TERM...(Today through Friday)
Issued at 327 AM EDT Wed Sep 14 2016
The main question is will there be more showers over the CWA this
morning as the back edge of the polar jet moves across the area.
Beyond that there is a question as to how cold it can get tonight
as skies should be clear and winds light.
The 90 knot jet core`s back edge moves across Lower Michigan
during the mid morning hours of today. There is an area of jet
lift associate with that. Given all the showers over WI at 3 AM it
would seem reasonable that what the HRRR has been showing will
come true... that is an area of showers will cross most of the CWA
in the 7am to 9am time frame.
After that little question skies will clear this afternoon and
tonight with the surface high overhead winds should also be light.
This could be one of the colder nights of the season so far. It
would not be out of the question some locations in our NE CWA may
see lows in the mid to upper 30s (Leota).
The next system will not bring enough moisture into the area to
bring showers into our CWA until after dark on Friday so not much
of an issue there.
.LONG TERM...(Friday night through Tuesday)
Issued at 327 AM EDT Wed Sep 14 2016
A low pressure system will move slowly east across the northern
Great Lakes region Friday night through Saturday and bring showers
and perhaps some thunderstorms. The convective threat is marginal
due primarily to weak instability.
The system will depart our region on Sunday but a few lingering
showers are still possible as an upper level trough moves through.
Medium range guidance trends indicate that temperatures will
continue to average around 10 degrees above normal through the long
range forecast period.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 736 AM EDT Wed Sep 14 2016
The area of showers moving through will be east of the area by 15z
or sooner. I do not think the showers will impact the visibility
much so I put VCSH at all TAF sites east of GRR. Skies will clear
after that (by 16z). Actually model sounding suggest a few cu
around 5000 ft early this afternoon so I put that at most of the
taf sites. Tonight skies should be clear and winds should be
light.
&&
.MARINE...
Issued at 327 AM EDT Wed Sep 14 2016
Surface high pressure should mean light winds and clearing skies
to I see no issues for the near shore until the next frontal
system moves into the area Friday night.
&&
.HYDROLOGY...
Issued at 326 PM EDT Tue Sep 13 2016
Mid-level frontogenesis near South Haven to Lansing Tuesday night in
a convectively unstable layer may yield a several hour period of
moderate rainfall. Basin average amounts around a quarter inch are
most likely but WPC does have the area south of Holland-Alma in a
marginal risk of rainfall exceeding flash flood guidance amounts. As
for rivers in the Grand and Kalamazoo basins, most are near to only
moderately above normal for mid-September, and most basins except
for the some of the headwaters should be capable of handling a few
hours of moderate rainfall.
&&
.GRR Watches/Warnings/Advisories...
MI...None.
LM...None.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...Laurens
AVIATION...WDM
HYDROLOGY...CAS
MARINE...WDM
Area Forecast Discussion
National Weather Service Omaha/Valley NE
627 AM CDT WED SEP 14 2016
.SHORT TERM...(today through Friday)
Issued at 353 AM CDT WED SEP 14 2016
Latest water vapor imagery and RAP analysis shows large mid-upper
level low centered over the Great Basin. Meanwhile, a large area
of surface high pressure extended from the Dakotas into the
Central Plains with the associated surface ridge axis currently to
our west. A ribbon of thunderstorms continues to move northeast
over northeast Kansas, extreme southeastern Nebraska and northwest
Missouri within an area of elevated instability. Most recent runs
of the CAMs show this area diminishing by sunrise so will hold on
to a small pop in our south through the morning. An extensive
area of low clouds/drizzle remains anchored over the area with
some clearing across far northeast Nebraska. Cloudy conditions
will likely continue through much of the day with patchy drizzle
confined to the southern CWA.
The above mentioned surface ridge axis will slide east of the area
tonight allowing warm southerly return flow to increase. Strong
isentropic upglide in the 300-305K layer should promote
widespread showers and isolated thunderstorms across central
Nebraska and Kansas late tonight and spread east throughout the
morning. In addition, previous mentioned Great Basin mid-upper
level low will be moving into the western Dakotas by this time, allowing
the associated trough axis to move over the High Plains with lead
shortwave energy ejecting out ahead of it. The associated surface
low is forecast to move across the Dakotas with a southward
extending cold front. Uncertainty remains on coverage of showers
and thunderstorms late Thursday morning and how much
destabilization can occur toward peak heating ahead of the
approaching cold front. Sufficient deep layer shear will be
present along with steepening mid level lapse rates as upper
impulse moves overhead. Strong to severe storms are not out of the
question late Thursday afternoon across central Nebraska and into
our western counties which could then spread east across the
entire forecast area Thursday night as the cold front slides east
overnight.
Quiet conditions are expected behind the front Friday but a few
lingering showers are possible in our eastern areas.
.LONG TERM...(Friday night through Tuesday)
Issued at 353 AM CDT WED SEP 14 2016
Relatively quiet conditions are expected Friday night through the
weekend as a surface high pressure moves overhead. Showers and
thunderstorms return to the forecast early next work week in warm
air advection regime. Temperatures in the extended should remain
above normal.
&&
.AVIATION...(12Z TAFS for KOFK...KLNK and KOMA.)
Issued at 620 AM CDT WED SEP 14 2016
MVFR CIGs are currently at all 3 TAF sites and this is likely to
continue over most of the period. We may see CIGs increase to VFR
at KOMA for a time late this morning and into the afternoon, but
these are likely to lower quickly again this evening. IFR
conditions are likely tonight with LIFR conditions possible at
KLNK and KOFK. Will keep the TAFs dry for now, but some light DZ
is possible at KOMA/KLNK this morning and some SHRA/TSRA are
possible just after this period at all 3 sites on Thursday.
&&
.OAX Watches/Warnings/Advisories...
NE...None.
IA...None.
&&
$$
SHORT TERM...Kern
LONG TERM...Kern
AVIATION...Boustead
Area Forecast Discussion
National Weather Service Tulsa OK
1044 AM CDT WED SEP 14 2016
...UPDATE...
.DISCUSSION...
Weak cold front extends from near Joplin to Okmulgee this morning
with extensive cloud cover noted on satellite mainly north of
I44. Decent pressure rises behind front suggest that it will
continue to move SE before washing out/stalling this afternoon. In
the near term...isolated thunderstorms developing across
Pawnee/Osage counties and Le Flore/far southern Sebastian counties as
well.
Have updated the grids to reflect the mostly cloudy skies in the
northeast and have maintained chance pops across the CWA.
Slightly better chance for thunder south of the front which agrees
with the latest HRRR guidance...but 12z NAM shows more development
north through 21z. Temps look ok given most areas will heat up
with some heating today even in cloudy areas.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 87 69 87 70 / 30 40 50 50
FSM 90 71 90 71 / 30 30 40 30
MLC 89 70 89 70 / 30 30 40 30
BVO 84 67 85 68 / 30 40 50 60
FYV 86 67 84 68 / 30 30 50 40
BYV 85 67 84 67 / 30 30 50 30
MKO 89 69 88 70 / 30 30 50 40
MIO 87 67 84 67 / 30 40 60 50
F10 88 70 88 69 / 30 30 50 30
HHW 91 71 92 71 / 30 30 40 30
&&
.TSA Watches/Warnings/Advisories...
OK...None.
AR...None.
&&
$$
CORFIDI
Area Forecast Discussion
National Weather Service Denver/Boulder CO
335 PM MDT WED SEP 14 2016
.SHORT TERM...(This evening through Thursday)
Issued at 335 PM MDT Wed Sep 14 2016
Scattered showers have been moving across the mountains this
afternoon, but nothing has developed on the plains yet. Moderate
to strong southwest flow aloft continues ahead of the trough axis
which is moving into the northwest corner of the state at this
time. The latest HRRR model runs continue showing a round of
showers moving over the plains during the evening, so will stick
with that. Gusty winds, brief rain and small hail will be the main
threat. The airmass on the plains looks like it will remain capped
until the upper trough moves out of the mountains.
On Thursday, westerly flow aloft will continue in the wake of
tonight`s upper trough. Temperatures will be a few degrees cooler
than this afternoon, but the airmass will become unsettled in the
afternoon, leading to isolated showers developing again. Mountain
areas may see a little bit more shower activity than on the
plains.
.LONG TERM...(Thursday night through Wednesday)
Issued at 335 PM MDT Wed Sep 14 2016
The upper trof will begin to move out into the northern high
plains Thursday night and Friday. This trof send a weak frontal
surge through Northeast Colorado with shallow upslope flow and a
bit cooler temperatures for Friday. Overall the airmass will be
drier on Friday but with heating and some lingering moisture there
will still be isolated afternoon/evening showers mainly over
mountains and higher terrain areas.
For Saturday, some warming but weak trofiness upstream will still
help support showers and thunderstorms mainly mountains and Palmer
Divide.
For Sunday through Tuesday there will be a drier West to Southwest
flow over Colorado. This will result in warmer temperatures with
readings back into the 80s across the plains through early next
week. By next Wednesday the next upper trof will sweep across the
region with the bulk of the moisture remaining North of Colorado.
Certainly some cooler temperatures and a slight chance of showers
for now. The european solution is much slower and low confidence
at this time on any one solution.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 335 PM MDT Wed Sep 14 2016
Convergence boundary has settled over the airport, causing a
variety of wind directions across the airfield. This boundary will
remain in the vicinity until showers come off the foothills to
displace the wind field. One or two rounds of showers will move
over the airports this evening, then decreasing clouds should
develop. Isolated showers will be possible again tomorrow
afternoon.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
SHORT TERM...Dankers
LONG TERM...Entrekin
AVIATION...Dankers
Area Forecast Discussion
National Weather Service Columbia SC
652 PM EDT WED SEP 14 2016
.SYNOPSIS...
Moisture will remain over the region through much of the week in
the easterly flow between high pressure to the north and Tropical
Storm Julia just south of the area. This will result in unsettled
weather, especially across the southern Midlands and CSRA.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
TS Julia remains a minimal tropical storm located just offshore
Fripp Island at 5 pm based on radar imagery. Showers have become
widely scattered across the Midlands and CSRA this evening. Tight
moisture gradient across the west Midlands/Piedmont. Based on
latest HRRR guidance and radar trends...cut pops back overnight
from previous forecast.
Julia is forecast to gradually lift northeastward along the coast
while widespread stratus is expected to redevelop over the area.
The cloud cover and possible showers will limit radiational
cooling and overnight lows will be in the upper 60s to lower 70s.
If winds fall off enough over the northern and western Midlands
there could be some patchy fog that develops.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Tropical Storm Julia will continue to be the main focus
through the end of the week and into the weekend as it lingers
near the SC coast. Surface high pressure over the Great Lakes this
afternoon will continue to build east and south through the end of
the week. This will continue the moist onshore flow along the
coast and hold Julia or her remnants near the coast. All of the
short term models move Julia very slowly northward tonight into
Thursday...then seem unsure were Julia will move. The center
appears to wobble in the vicinity of srn SC/sern GA through the
weekend. Very tight precipitable water gradient across the area
this afternoon and expect this to continue through Thursday. Values
over 2.0 inches over much of the central and eastern Midlands into
the CSRA. This is approximately 125 to 150 percent of normal for
this time of year. So any showers/thunderstorms that develop over
the region will have the potential to produce locally heavy
rainfall. Kept the highest pops across the southeast Midlands into
the CSRA. Cloudiness should limit instability and with such a
moist atmosphere severe thunderstorm chances should remain low.
Followed the guidance consensus for high temperatures in the low
to mid 80s and lows in the upper 60s to lower 70s.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
The GFS and ECMWF indicate high moisture through much of the
medium-range period associated with a long-fetch easterly flow
south of pressure ridge...and remnants of Julia that become more
diffuse...off the east coast. A cold front approaching from the
northwest may move into the forecast area Monday. Expect mainly
scattered showers and thunderstorms especially near the times of
maximum heating with coverage limited by upper ridging. The GFS,
ECMWF, and EKD MOS support pops 30 to 50 percent. The MOS
indicates near normal temperatures through the medium-range
period.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Generally VFR conditions, outside of scattered showers and isolated
thunderstorms, through early evening. TS Julia centered near the SC
coast. Most associated moisture and precipitation south of our
terminals, with drier air to the north and west of the cyclone. On
the northern tier of the circulation, scattered showers and a
possible isolated thunderstorms moving west over our FA enhanced by
diurnal heating. Will expect much of this activity to diminish by
early evening. Concern will then shift to stratus development
tonight due to E to NE low level flow and moist low levels. Guidance
in good agreement with stratus formation, and stratus could develop
relatively early in the night. Expect a slow lift to VFR by late
morning to midday Thursday. Juila expected to move very slowly near
of just offshore the SC coast. Expecting mainly diurnal scattered
showers and an isolated thunderstorm for our FA Thursday.
For now, think VCSH will suffice.
EXTENDED AVIATION OUTLOOK...Chance of mainly afternoon/evening
thunderstorms, as well as late night/early morning fog/stratus.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
Area Forecast Discussion
National Weather Service Dodge City KS
318 PM CDT WED SEP 14 2016
...Updated Long Term Section...
.SHORT TERM...(This evening through Thursday)
Issued at 1244 PM CDT Wed Sep 14 2016
Water vapor loop and RAP analysis showed a mature mid-latitude
cyclone spinning over southeastern Idaho into adjacent western
Wyoming. There was also a subtropical jet streak nosing into western
Kansas, with a plume of mid level moisture extending from
southeastern Arizona through central New Mexico into the Central
Plains. There were a few sprinkles and very light rain showers over
southeastern Wyoming into the western Oklahoma Panhandle, but as of
midday, these were starting to dissolve. Low clouds were still
holding tough across far western into northern Kansas, which were
keeping temperatures down into the upper 50s to around 60. The low
level flow was very weak with a remnant surface high in place. This
will weaken and shift quickly east, being replaced by a leeside
trough across eastern Colorado. Strong and isolated severe
thunderstorms along and a little east of the I-25 Urban Corridor of
Colorado will shift east this evening, but will encounter an
increasingly stable atmosphere and should die off by the time they
reach the Colorado border. We will hold on to some 20-30 POPs across
the far western sections of the forecast area, mainly Elkhart to
Johnson to Syracuse. We will also continue POPs, but lower them a
bit over the remainder of west central and southwest KS, as it
appears the warm air advection will be strongest farther north into
Nebraska and northern Kansas.
For Thursday, a warm up is in store with a return to southerly winds
along with increased moisture. A trough axis will set up from east
central Colorado into central Nebraska, and this should be a focus
for late afternoon and evening thunderstorm development. Again, the
best focus should be farther north where stronger mid and upper
level winds will be. This is also where the SPC Day 2 Slight Risk
resides, which barely clips parts of west central KS (including
Wakeeney and Hays). Any thunderstorm activity south of this area
deeper into southwest KS should be isolated to widely scattered in
nature as far as coverage goes, given the weaker forcing for ascent.
.LONG TERM...(Thursday night through Wednesday)
Issued at 317 PM CDT Wed Sep 14 2016
On Friday, the best area for convective activity will be across far
south central KS as the frontal boundary tied to the Northern Plains
upper low continues to push south. A subtropical jet core will
extend from southern New Mexico into southern and eastern Kansas,
and would provide enough deep layer shear to support some organized
severe thunderstorm structures. That said, the low level kinematics
will be rather poor, so inflows into convective storms could be a
detriment to organized severe storms. The southern branch jet will
not change much on Saturday, but a weak surface high will have
greater influence, so precipitation chances Saturday look fairly
low, except perhaps along the Oklahoma border where better residual
moisture will reside. Weak upslope flow in southeastern Colorado may
initiate a few storms as well, which could roll into far southwest
KS by late afternoon/early evening.
Beyond Saturday, the synoptic pattern will shift back to northern
branch dominance, as a very strong Pacific jet noses into the
Pacific Northwest region and Northern Rockies. The synoptic pattern
will favor a warm up back into the 80s early next week, but overall
precipitation chances will be lower as there will be an absence of
forcing for ascent with only weak flow in the mid levels across the
Rockies. There is a big discrepancy between the deterministic ECMWF
and GFS going into mid next week, as the GFS shows a big trough
moving into the Central Rockies, whereas the ECMWF keeps the lowest
heights way out along the West Coast (and hence dry over our part of
the world).
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1244 PM CDT Wed Sep 14 2016
Light winds will become south at around 10 to 13 knots this evening
at GCK and DDC. Stratus clouds should remain in a scattered coverage
through the period at GCK and DDC as warmer air pushes back in from
the south, but farther north at HYS where the moisture advection
will be best overnight, low stratus and at least some light fog
should form. This is the only terminal we will bring in some LIFR
conditions for roughly a 4 hour period early tomorrow morning.
Confidence in organized precipitation is too low to include at the
terminals through midday Thursday.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 62 84 61 80 / 20 30 60 30
GCK 60 84 59 77 / 20 30 40 20
EHA 59 85 58 77 / 30 20 30 20
LBL 60 85 60 80 / 20 30 50 30
HYS 60 82 60 78 / 40 40 60 20
P28 63 84 65 82 / 20 40 60 50
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Umscheid
LONG TERM...Umscheid
AVIATION...Umscheid