Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/26/16
Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
926 PM CDT Sun Sep 25 2016
.DISCUSSION...A weak cold front currently extends from near
Texarkana to Zapata. Numerous showers and thunderstorms continue
to develop along the boundary mainly across Zapata, Starr and Jim
Hogg Counties. The latest HRRR and NAM suggests that this
convection will move east and gradually weaken overnight.
However, the NAM shows some additional development near the coast
around sunrise. Have updated the overnight grids to reflect
current thinking and for observational trends. A flash flood
watch may be needed later tonight or Monday due to the high
rainfall rates, precipitable water values over 2 inches, and the
slow moving boundary across the area.
&&
.PREV DISCUSSION... /issued 705 PM CDT Sun Sep 25 2016/
DISCUSSION...Updated for latest aviation discussion below.
AVIATION...Moderate and gusty southeast winds prevail across deep
south Texas this evening. Latest BRO radar indicates scattered
showers and thunderstorms the extreme western portions of the CWA.
This activity is associated with a weak cold front approaching the
area. THe latest HRRR and NAM models suggest that some of this
activity could reach the TAF sites after midnight, mainly after
09z. Otherwise, winds will gradually diminish by later this
evening with some brief MVFR ceilings possible overnight. Rain
chances will increase on Monday as the front approaches from the
west and moisture pools ahead of it.
PREV DISCUSSION... /issued 221 PM CDT Sun Sep 25 2016/
SHORT TERM (Tonight through Monday Night): A negative tilt H5
trough is moving laterally from west to east across the upper plains
today. It extends a weakness southwest to a cutoff low over North-
west Mexico. High pressure is over the central high plains and a
cold front is pushing out ahead of that high pressure over North
Central Texas. High pressure is also over the Gulf of Mex, driving a
moderate southeast flow over the CWA, pumping moisture ashore.
Marine showers are ongoing over the Gulf adjacent to the CWA, while
isolated to scattered afternoon convection is developing over the
CWA.
Daytime convection should decrease this evening as heating subsides,
however, there is enough moisture such that it may not entirely
disappear, especially over the Gulf and along the coast tonight.
Plus, a few showers may push south ahead of the front, whose
transection of the Rio Grande should end up between Del Rio and
Laredo tonight. Despite somewhat more robust pop percentages than
usual of late, QPF amounts will remain relatively low, at a quarter
of an inch or less. Overnight low temperatures will be in the mid
70s with a light east southeast wind.
The NAM starts out the work week Monday morning with ongoing Gulf
showers and streamers moving onto the coast and over the Lower
Valley, even reaching the southern Mid Valley. Though convective
coverage will be in the numerous category, overall QPF still looks
manageable at under a half an inch, though some locally heavier
downpours will be possible. Light winds will back from east
southeast early Monday morning to east northeast through the day.
Max temperatures will be slightly lower than today, mainly in the
mid to upper 80s.
A shift to north winds Monday night signals that the front will edge
into the area, but marginally drier air will not push all the way
through, and the front may hang up at the coast. QPF amounts again
still look modest at less than half an inch, although heavier
amounts look feasible over the Gulf. Overnight low temperatures will
be a bit less than tonight, in the lower to mid 70s.
LONG TERM (Tuesday through Sunday): The main effort in the long
term portion of the forecast was to reduce rain chances and shift
the focus of the precipitation to along the immediate coastal area
and the adjacent coastal waters in the wake of the above-mentioned
cold front. Isolated to scattered thunderstorms and/or showers
are forecast Tuesday through Thursday as deep tropical moisture
remains in place near the coast in the wake of the front. The
atmosphere will then rapidly dry beginning Thursday night and
afterwards, leading to dry weather at that time and through the
remainder of the forecast. Temperatures tempered to near normal
levels immediately in the wake of the front will gradually warm to
above normal levels by the end of the forecast period courtesy of
abundant sunshine and limited cloud cover.
MARINE (Tonight through Monday night): High pressure over the
Gulf will be countered by a weak area of low pressure over the
Southwest Gulf and by the approach of a weak cold front pushing
slowly through South Central Texas tonight. Moderate southeast
winds today will weaken and shift to east tonight, and will then
become light to moderate northeast on Monday. Winds will back to
north and will become moderate Monday night as the front moves
near to and over the lower Texas Coast. Seas will remain low to
moderate through the short term. Isolated to scattered showers
with embedded thunderstorms will continue over the marine areas.
Tuesday through Sunday: Moderate generally northeast winds and
moderate seas will prevail through the period in the wake of the
cold front discussed above. Wind speeds may be strong enough on
all or portions of the Lower Texas coastal waters Tuesday and
Tuesday night to warrant a Small Craft Exercise Caution.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 79 89 77 86 / 40 50 60 40
BROWNSVILLE 79 90 76 87 / 40 50 60 40
HARLINGEN 77 90 75 86 / 40 60 50 40
MCALLEN 79 91 74 88 / 40 60 40 30
RIO GRANDE CITY 78 91 73 85 / 60 60 50 30
SOUTH PADRE ISLAND 81 87 78 83 / 50 60 70 50
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
This product is also available on the web at:
HTTP://WEATHER.GOV/RGV
63
Area Forecast Discussion
National Weather Service Columbia SC
1042 PM EDT SUN SEP 25 2016
.SYNOPSIS...
An upper-level ridge will continue to build east across the region
tonight then move off the coast Monday. A cold front moving into
the area tonight will stall across the area Monday providing a
focus for scattered showers and thunderstorms. Another cold front
will cross the area Tuesday night into Wednesday. The air mass
behind this system will bring dry weather and more seasonable
temperatures for the latter half of the week.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
A high amplitude upper-level ridge over the Tennessee/Ohio valley
region will continue to move slowly east overnight. Upper-level
cut-off low over the Gulf coast area. At the surface, weak high
pressure remains. Upper-level trough over New England with surface
ridge building south along the Atlantic Seaboard will drive the
cold front slowly southwest tonight. The front appears to be along
the nc/sc border this evening. Convergence along the front and
upper- level dynamics appear weak. Have forecasted slight chance
pops overnight. With low clouds spreading southward...shown by
bufkit time sections...could see a better chance of very light
rain/drizzle toward morning. Overnight lows generally in the
upper 60s to around 70 degrees.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
Easterly low-level flow Monday resulting in deeper moisture. A
stalled frontal boundary across the area will support scattered
showers and thunderstorms in a weakly to moderately unstable air
mass. Convection may focus near a sea breeze front in the east Monday.
Deep upper low along the US/Canadian border Monday is forecast to
move southeast into the Ohio River Valley by Wednesday. Thus will
push a cold front through our area late Tuesday into Wednesday.
We`re still seeing some timing differences with the 00Z ECMWF
holding the upper low and cold front farther west. The 12Z GFS AND
12Z NAM are more progressive moving the cold front to the coast by
the end of the day Wednesday. We have continued the chance for
convection ahead of the front Tuesday then diminishing from west
to east Wednesday as the cold front moves east of the Midlands.
Temperatures are expected to remain above normal ahead of the
front Monday and Tuesday, with highs in the mid to upper 80s and
lows in the mid 60s to lower 70s. Should see slightly cooler
temperatures Wednesday with highs in the low to mid 80s.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
Typical fall weather to spread across the region for the end of
the week with seasonable temperatures.
Dry and cooler air advecting into the region Thursday. Surface
high pressure and stable conditions spreading across the region
into next weekend. Deep upper trough crossing the eastern states.
Overnight lows expected to range from the 50s to lower 60s with
afternoon highs in the mid 70s to lower 80s.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Weak convergence associated with a backdoor cold front moving
into the area will help support stratus and fog development
tonight. Most of the NAM and GFS MOS plus HRRR suggested mainly
IFR stratus. Followed the GFS LAMP for the timing. Continued upper
ridging should help keep moisture shallow. Nocturnal cooling
should limit instability. The shower and thunderstorm chance
overnight was too low to include in the terminal forecasts at
this time. The diffuse front will remain in the area though the
rest of the TAF period but some diurnal ceiling improvement
should occur. The GFS and NAM MOS were in good agreement with
generally VFR conditions developing during the day. Some increase
in moisture will occur in an easterly flow Monday. The moisture
and some convergence associated with the diffuse front in the area
plus heating should support scattered showers and thunderstorms
but still expect limited coverage with significant forcing
associated with the next approaching cold front west of the area
through the TAF period. Again, the shower and thunderstorm chance
was too low to include in the terminal forecasts at this time.
EXTENDED AVIATION OUTLOOK...A slow moving cold front will be in
the area through Wednesday. Widespread stratus and fog may occur
especially during and late night and early morning hours. There
will also be scattered showers and thunderstorms. Drying may occur
behind the front Thursday.
&&
.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 Corpus Christi TX
830 PM CDT SUN SEP 25 2016
.DISCUSSION...
Line of convection has filled in across central portions of the
area and will move very slowly eastward tonight. The leading edge
of the convection is producing rather high rainfall rates within
2+ inch pwat air. Have gone ahead and issued a flash flood watch
through the overnight for locations west of Beeville to Alice
line. Meso models are not doing a great job with the development
of this activity, but HRRR which seems to have the best handle on
it keeps moderate to heavy rain over the region through the night.
&&
.PREVIOUS DISCUSSION... /Issued 639 PM CDT SUN SEP 25 2016/
DISCUSSION...
Cold front enhanced by convective cold pool is now analyzed into
northwestern CWA. The front will gradually move through, but the
main push of slightly cooler air will be later in the day on
Monday associated with mid and upper level support. Expect current
line of convection to gradually weaken as it pushes eastward
through the evening, but at least scattered convection will
continue across the region through the night. Meso models are in
general agreement in developing another area of showers and
thunderstorms later tonight in far northwest CWA. In general
expect severe threat to remain low. Some storms could have gusty
winds but largely expect below severe limits. Main concern would
be localized heavy rain and potential flash flooding.
AVIATION...MVFR to VFR conditions expected through the period
with chances for showers and thunderstorms throughout. Cold front
currently running from roughly San Antonio to Laredo will
gradually push eastward overnight. Mainly northeast to northerly
winds likely behind the front. Some thunderstorms with gusty winds
are possible across the region tonight through Monday.
PREVIOUS DISCUSSION... /Issued 421 PM CDT SUN SEP 25 2016/
SHORT TERM (Tonight through Monday)...
An upper level trough positioned over the central plains will
continue trekking eastward as a cut off low retrogrades over
northern Mexico and the Baja Peninsula overnight and Monday. A
cold front draped across central Texas will slowly progress
southward into the region Monday. There will be a lull in
convection over the Coastal Bend and portions of the Coastal
Plains this afternoon and early evening, but expect redevelopment
of convection overnight. As the boundary pushes further south
anticipate numerous showers and thunderstorms to develop, with the
best chances across the Rio Grande Plains early in the period,
spreading in coverage late tonight into tomorrow. Higher pwat
values over 2 inches will be spread across the region. Deep
Pacific moisture is being ushered into the region with the cut off
low over northern Mexico, and more low level moisture from the
Gulf is also being brought onshore with moderate onshore flow
today. Moderate to locally heavy rainfall will be possible at
times will some of these storms, but with storm motion moving at
current rates, widespread flooding is not expected at this time.
Surface winds ahead the frontal boundary will become easterly
overnight, gradually becoming northeasterly through the
afternoon. Tonight temperatures will be a few degrees cooler than
the past couple of days. Highs tomorrow will be somewhat dependent
on coverage of rain and timing of the cold front moving into the
region. Currently anticipate highs in the low to mid 80s inland,
and in the mid to upper 80s along the coast and southern Coastal
Bend.
LONG TERM (Monday Night through Sunday)...
Models prog the upper cut off low to continue retrograding
westward across Baja CA while the main upper low continues to
swing eastward across the plains, with mid/ upper level high
pressure in between across S TX. This will lead to sfc high
pressure continuing to build across S TX through Monday night and
Tue. As a result, sfc winds restrengthen Monday night to moderate
levels, mainly across the waters. Models also hint at weak re-
enforcing high pressure once again Thu, resulting in a slight
increase in sfc winds briefly Thu. A gradual drying will take
place with pops decreasing from N to S through Tue. The GFS shows
precip continuing along the southern coastal waters through Wed as
an upper level short wave tracks south around the eastern
periphery of the ridge. Therefore, kept a slight chc across the
southern coastal waters through Wed/Wed night, then remove the
mention of precip completely by Thu. Expected to remain dry into
the weekend then re-introduce pops across the waters next Sun.
Temps will be cooler Tue due to the combination of weak to mod CAA
and clouds/rain, then a gradual warming through the latter part of
the week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 76 88 72 85 71 / 50 70 50 40 20
Victoria 72 85 68 84 67 / 60 60 40 30 10
Laredo 75 87 68 79 68 / 80 60 60 30 10
Alice 74 88 71 85 69 / 60 60 50 30 10
Rockport 77 88 73 83 73 / 50 60 50 40 20
Cotulla 73 81 67 81 67 / 80 60 50 30 10
Kingsville 75 88 71 85 70 / 50 70 50 40 20
Navy Corpus 78 87 75 84 75 / 50 70 50 40 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...Flash Flood Watch until 7 AM CDT Monday For the following zones:
Bee...Duval...Jim Wells...La Salle...Live Oak...McMullen...
Webb.
GM...None.
&&
$$
PZ/83...SHORT TERM
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
925 PM CDT SUN SEP 25 2016
.UPDATE...
Earlier rains produced an axis of radar estimated accumulations of
1.5-2.5 inches across Kendall and Bexar counties, while amounts
farther south into southern Atascosa county are as high as 4-6
inches. Radar trends along with some recent hi-res model guidance
suggests rainfall will continue to slowly expand across areas
generally west of a Fredericksburg to San Antonio to Kenedy line.
Based on the above, we have decided to expand the Flash Flood
Watch to include Kendall, Bexar, Atascosa, Wilson and Karnes
counties.
&&
.PREV DISCUSSION... /ISSUED 711 PM CDT SUN SEP 25 2016/
AVIATION.../00Z TAFS/
Although showers are ongoing at the I-35 TAF sites, none are
currently experiencing thunderstorms as one line of thunderstorms
is moving north of GTU while another more intense line develops
along an outflow boundary or cold front SE of PEZ. This line
extends southwest towards LRD and APY and is slowly propagating to
the SE with some elements overrunning the boundary to the north.
Showers with very isolated embedded thunderstorms are expected at
the I-35 TAF sites, but lightning potential remains too low to
mention for the next six hours at any site. Ceilings for the I-35
TAF sites should gradually lower but generally remain MVFR for the
next six hours, while DRT should main VFR for the most part.
The larger- scale cold front currently south of the I-20 corridor
to our northwest will continue to push southeast. A midlevel
shortwave moving north across the Rio Grande in Mexico will help
provide some additional upper level support to allow additional
showers with embedded thunderstorms to develop as this front
approaches before convective potential decreases behind the front.
Thus, have included TEMPO groups for thunderstorms between 6-9Z
for SAT/SSF and a PROB30 group for DRT between 9-12Z. The 21Z and
22Z HRRR model runs that are best handling the current scenario
both keep thunderstorms out of AUS, so have done the same. Patchy
fog may end up being a greater concern at AUS due to saturated
soils and greater cold air advection, so currently have LIFR
ceilings and visibilities there between 9-15Z.
PREV DISCUSSION... /ISSUED 422 PM CDT SUN SEP 25 2016/
SHORT TERM (Tonight through Monday Night)...
The complex of showers and thunderstorms that continues to track
E-NE along the Escarpment on the cool side an outflow boundary
continues to produce up to 2 inches of rain per hour. The storms
are becoming less organized as the cold pool has propagated away
from better dynamic support aloft associated with a cutoff mid-to-
upper level low retrograding in the Mexican state of Sonora.
Although an MCV that briefly developed over the western Hill
Country has dissipated, there still is plenty of instability
south of the surface boundary where temperatures have warmed to
around 90 degrees. In addition, differential heating on both
sides of this boundary may also be generating frontogenetical
forcing that combined with southerly flow up the Escarpment, will
continue to encourage additional scattered to widespread showers
and thunderstorms through early evening. Thus, the Flash Flood
Watch has been extended east by one row of counties in the Hill
Country to account for heavier rainfall totals. Along and east of
I-35, lower 1-3 inch totals are expected through this evening as
storms should move fast enough to prevent higher totals.
Heavier rainfall totals did occur over the western Hill Country
and Edwards Plateau this morning where widespread 2-4 inch totals
fell with isolated areas receiving over 6 inches. The hardest hit
area appears to be in eastern Edwards County where up to 8 inches
of rain has fallen causing the closure of all roads into and out
of Rocksprings. Heavy rain has also prompted closures in parts of
Real and Kinney Counties. These areas have stabilized in the wake
of the complex that passed through as stratiform rain falls, so
additional convective development is not expected there for the
next few hours. However, stronger isentropic ascent will arrive
this evening as the synoptic cold front along the TX-OK border
arrives and clearing prior to sunset may allow destabilization to
occur. Any additional rainfall would accentuate ongoing flooding
in these areas, so the Flash Flood Watch remains in effect there.
The greatest potential for locally heavy rainfall through Monday
morning is in the Rio Grande Plains, particularly along and south
of the weak surface boundary oriented near US Highway 57. Although
the cutoff low is retrograding further to the west, it has kicked
off a shortwave that is helping generate showers and thunderstorms
in Coahuila. All models continue to lag behind the actual
progression of this system, but a few hi-res models continue to
suggest that some training of storms could occur along the surface
boundary with additional dynamic support aloft from the shortwave.
Thus, we have included Maverick, Zavala, Dimmit, and Frio Counties,
but the threat should remain low in over the next few hours if
the surface boundary continue to propagate south and east. As the
storms over Mexico expand and move north as they deepen by this
evening, heavier convective rainfall may occur over the Rio Grande
Plains and move into Val Verde County and the Edwards Plateau as
rain becomes more stratiform in nature. However, confidence is low
in this solution given all models continue to be less progressive
with the overall system and front than has occurred today, and the
passage of the front would reduce the heavy rainfall threat.
Scattered to widespread rain showers with isolated thunderstorms
will be possible across the region tomorrow due to isentropic
ascent allowing for moisture to overrun the front. However, rain
totals should remain below a quarter inch for most areas except
closer to the Rio Grande Plains where heavier rainfall closer to
an inch will be possible. Cloud cover and N-NE winds will cause
much cooler high temperatures in the 70s and lower 80s on Monday
with perhaps upper 60s in the Edwards Plateau.
LONG TERM (Tuesday through Sunday)...
More tranquil and pleasant fall weather is on the way once rain
chances end from northeast to southwest Monday evening through
Tuesday. An upper level ridge will materialize between the
retrograding closed low in the Pacific and another closed low
digging from the Midwest into the Southeast U.S. by Wednesday.
This digging low will allow reinforcing shots of cooler air to
keep temperatures slightly below normal in the 80s with clear
skies and dry conditions through next weekend. Low temperatures
will be in the mid 50s to mid 60s for much of next week due to
clear skies and continued weak northerly winds overnight. The best
time of year weather-wise in South Central Texas has arrived!
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 69 77 63 79 63 / 70 50 20 10 -
Austin Bergstrom Intl Airport 69 78 63 80 61 / 70 50 20 10 -
New Braunfels Muni Airport 69 78 63 81 62 / 70 60 30 20 10
Burnet Muni Airport 65 72 60 77 60 / 70 50 20 10 -
Del Rio Intl Airport 68 72 60 72 62 / 80 70 60 30 10
Georgetown Muni Airport 67 74 62 78 60 / 70 40 20 10 -
Hondo Muni Airport 70 78 63 80 63 / 80 60 40 20 10
San Marcos Muni Airport 69 78 63 80 62 / 70 50 30 20 10
La Grange - Fayette Regional 71 82 67 82 64 / 70 50 20 10 10
San Antonio Intl Airport 70 78 64 80 63 / 80 60 40 20 10
Stinson Muni Airport 72 80 66 82 65 / 80 60 40 20 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 7 AM CDT Monday for the following counties:
Atascosa...Bandera...Bexar...Dimmit...Edwards...Frio...Gillespie...
Karnes...Kendall...Kerr...Kinney...Maverick...Medina...Real...
Uvalde...Val Verde...Wilson...Zavala.
&&
$$
Mesoscale/Aviation...05
Synoptic/Grids...24
Public Service/Data Collection...30
Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
631 PM CDT SUN SEP 25 2016
.AVIATION...
/00Z TAFS/
Cold front continues to make southward progress this evening and
is currently located from just south of Abilene northeast toward
Bowie. Winds ahead of the front are already out of the north and
generally around 10 kt but as the front comes through...wind will
increase to 15 to 20 kt for a few hours. Scattered showers
continue along and north of the front at this hour and expect that
there will be period of shower activity through the overnight
hours.
For the latest set of TAFs...will prevail MVFR conditions as cigs
continue to come down. They are generally running around 2500 ft
this evening. Later tonight as the front continues south...the
frontal inversion will deepen with ample moisture remaining in
place. Ceilings should continue to lower through the overnight
hours with more substantial dry air advection holding off until
later tomorrow morning. MVFR cigs with heights between 1000-1500
ft should prevail with periodic showers. Conditions will slowly
improve during the day Monday as drier air moves in behind the
front. VFR conditions are expected by afternoon with precipitation
ending and north winds diminishing.
At Waco...scattered showers and thunderstorms will be more
prevalent through the remainder of the evening. Will continue with
a VCTS in the latest TAF with a tempo for -TSRA for a few hours
through about 10pm. Similar to farther north...ceilings should
lower during the overnight hours as the front spread south. A few
hours of IFR cigs will be possible during the early morning hours.
Cigs will improve later in the day with VFR conditions expected by
mid afternoon.
Dunn
&&
.PREV DISCUSSION... /ISSUED 321 PM CDT SUN SEP 25 2016/
As showers and thunderstorms continue across mainly the eastern
half of the region this afternoon, a cold front is racing towards
North Texas. The location of the actual front is muddled among
precipitation in NW Texas but the front is expected to enter our
northwest counties in just a few hours. It will continue to
steadily progress south and southeast tonight bringing cooler and
eventually drier weather to the region. But before we get to the
dry, pleasant weather expected this week, we have some challenging
rain chances/trends to discuss first.
An outflow boundary that has persisted since this morning is still
slowly moving east this afternoon. The outflow boundary stretches
pretty much along where moderate to heavy convection is occurring
to the east of Interstate 35/35E. The steering flow is from the
south which has resulted in training of storms along and near the
boundary for much of the day. This trend is expected to continue
into the evening hours as the boundary continues to push east. The
HRRR indicates weakening of this activity around sunset. Showers
and storms near this boundary have been very efficient rainfall
producers, and where training of cells has occurred, rainfall
totals of 2-4 inches in 1-2 hours have been reported. So far, no
significant flooding issues have been reported. Flash flood
guidance is high because of the dry period we have been in
recently, but minor flooding of low-lying areas, creeks, streams,
and streets/roads will continue to be a threat due to the higher
rainfall rates.
As the front moves through the region this evening and tonight,
expect an increase in rain across the region. The upper level
dynamic forcing is not very strong with an upper level low well
to our west and an upper level ridge to our east. With a
relatively cool and overworked environment in place across North
and Central Texas, and north winds already in place ahead of the
front, confidence is low in how much additional rain activity will
develop with the front. However, moisture content is still high
with dewpoints in the upper 60s and lower 70s, so at least some
additional rain is expected tonight. Hi-res guidance suggests some
robust cells may occur, potentially aided by a northward moving
shortwave currently near Sonora (south of San Angelo). For the
evening and overnight period, will continue with likely PoPs
across all but the area along the Red River and our far northeast
counties. Rainfall amounts may not be as high overnight as they
have been today, but it does appear much of the area could at
least see light to moderate rain at some point. Additional
rainfall amounts up to 1 inch are possible overnight with isolated
higher amounts.
Rain chances on Monday are still questionable due to considerable
spread in the guidance, but we anticipate much of the region will
remain dry as the cold front pushes south. North and Central Texas
will be under weak ridging aloft between the upper level low over
Baja California and an upper level trough moving across the
Midwest. While surface dry air will start filtering into the
region, deeper layer dry air will be slower to arrive and some
elevated isolated showers or storms may develop. As the drier air
deepens across the region on Tuesday, it should bring a final end
to any precipitation. For Monday and Monday night, will carry low
chances for rain generally along and south of Interstate 20.
The remainder of the week looks dry and pleasant. Generally north
winds at the surface all the way south into the Gulf of Mexico
will severely limit moisture return through the week. An upper
level ridge will re-establish over the region but the drier air
will keep temperatures pleasant with highs in the 70s and 80s and
overnight lows in the 50s and 60s. Humidity values will also
remain low with the lack or moisture return.
JLDunn
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 65 75 60 79 58 / 60 20 10 10 0
Waco 66 76 59 79 56 / 70 20 20 10 5
Paris 65 77 56 79 55 / 40 10 10 5 0
Denton 63 74 53 77 52 / 60 10 10 5 0
McKinney 64 76 55 78 53 / 60 10 10 10 0
Dallas 66 75 61 81 59 / 60 20 20 10 0
Terrell 66 77 59 79 55 / 60 20 20 10 0
Corsicana 67 78 59 80 58 / 70 20 20 10 0
Temple 66 75 59 77 57 / 70 40 20 10 5
Mineral Wells 61 71 53 76 52 / 70 20 20 10 0
&&
.FWD Watches/Warnings/Advisories...
None.
&&
$$
Area Forecast Discussion
National Weather Service Indianapolis IN
1010 PM EDT SUN SEP 25 2016
.UPDATE...
The Aviation Section has been updated below.
&&
.SYNOPSIS...
Issued at 304 AM EDT Sun Sep 25 2016
A cold front will move through the area tonight into early Monday
bringing showers and a few thunderstorms to the area. An upper low
could bring a few showers to northern areas mid week. Dry conditions
will then prevail. After one more warm day today, cooler and more
seasonable readings will continue into next weekend.
&&
.NEAR TERM /Tonight/...
Issued at 951 PM EDT Sun Sep 25 2016
Left likely pops in overnight as radar was national radar
mosaic was showing decent upstream coverage.
Previous discussion follows...
Issued at 618 PM EDT Sun Sep 25 2016
Moved pops about 25 miles or so further east over the next few hours
based on radar trends.
Previous discussion follows...
Issued at 220 PM EDT Sun Sep 25 2016
Vorticity lobe currently drifting through western Illinois may spark
off some convection later this afternoon and evening, especially
over the western zones.
Appears better precipitation threat will arrive later tonight as
model data suggest cold front will be moving into the northwestern
border zones around 260400Z. There appears to be decent upper
support aloft associated with this front, given a mid level jet max
around 70 kts, but most of the support lags behind the front. As a
result, think most of the precipitation will be near the front and
in the post frontal zone. Will go with the highest PoPs during the
late night hours tonight and into the pre dawn hours of Monday,
timed with the better upper support.
Low level thicknesses generally support the GFS MOS guidance lows
tonight.
&&
.SHORT TERM.../Tonight through Tuesday night/
Issued at 304 AM EDT Sun Sep 25 2016
Focus is on chances for rain. Models are close enough that a blend
was used.
The cold front will move through the area tonight. An upper jet will
provide additional forcing while 850mb winds over 30kt bring in
additional moisture. Decent frontogenetical forcing will be around as
well. Thus went likely PoPs most areas at some point during the
night, with later timing in the east.
Current expected timing of the system keeps rain still likely over
the east 3/8 of the area or so during the early part of the morning.
However, dry air moves in rapidly, so that by 15Z most areas are dry
and by 18Z everywhere is. Instability on Monday looks quite low so
removed any thunder mention.
Dry conditions should then prevail through Tuesday high pressure
nosing in.
An upper low will begin to move south out of the Great Lakes late in
the period. Models differ on path and how far south the rain gets by
late Tuesday night. Forcing doesn`t look impressive, and given the
uncertainty, was only comfortable adding in slight chance PoPs in
the extreme northeast forecast area.
For temperatures, generally stayed close to the model blend. Given
the dry air that will be in place for much of the short term, there
should be some decent diurnal ranges. The blend captures this pretty
well.
&&
.LONG TERM /Wednesday Night through Saturday/...
Issued at 242 PM EDT Sun Sep 25 2016
ECMWF showing some differences from superblend this period as the
ECMWF suggests that an upper low will settle across the Ohio
Valley through this period...pivoting several waves through the
area. GFS keeps this feature farther east...mainly over the middle
atlantic states. Thus confidence is low for now and have included
superblends low pops where it has been allowed. Confidence remains
low. However northwest continental flow does seem prevalent through
the period which should result in near normal tempertures.
&&
.AVIATION /Discussion for 260300z TAF issuance/...
Issued at 1010 PM EDT Sun Sep 25 2016
Brought VCTS in an hour earlier (to current time) at KIND and added
an hour tempo group for TSRA through 3z. No other changes made.
Previous discussion follows...
A cold front will move through the sites during the period and
bring showers and thunderstorms with it. These will bring brief
MVFR conditions, but outside of the storms ceilings at the sites
look VFR for the most part. Some scattered prefrontal showers and
storms will continue sporadically for the next six hours or so
and could impact the sites but confidence and coverage are not
high enough to go with any more than vicinity mention. Then around
6-8z HRRR shows prefrontal storms increasing in coverage near the
sites, and around 9-10z a line of storms associated with the front
should move into KLAF and KHUF and the other sites an hour or so
later. Could see a brief period of MVFR ceilings behind the
frontal passage, but upstream observations indicate the post
frontal clouds may stay VFR, and the rest of the day should be VFR
with wind gusts picking up to around 20-25 kts out of the NW by
midmorning.
&&
.IND Watches/Warnings/Advisories...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...JAS/MK
SHORT TERM...50
LONG TERM....PUMA
AVIATION...CP
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
928 PM CDT SUN SEP 25 2016
.UPDATE...
928 PM CDT
Water vapor imagery this evening depicts a very impressive mid-
level PV anomaly digging east-southeastward into northern Iowa.
This feature is expected to shift over northern Illinois by
daybreak Monday. In response to this, synoptic scale forcing for
ascent will increase over the area tonight, noted by the
development of good Q-vector convergence over the area. This in
addition to strengthening lower-level frontogenesis will setup an
anafrontal type precipitation event over the area tonight. In
fact, recent radar trends suggest this area of precipitation is
already rapidly developing across western IL. With this in mind, I
have increased POPs some overnight.
Westerly winds will also be gusty tonight as the surface cold
front, now moving towards the western Chicago suburbs, moves over
the area. Expect a period of gusty westerly winds of 25 to 30 KT
to move into northeastern Illinois by 11 PM with the frontal
passage. Gusty westerly winds will also continue over the area on
Monday, with gusts up to 30 KT expected.
KJB
&&
.SHORT TERM...
136 PM CDT
Through Monday...
Warm and humid conditions are in place early this afternoon ahead of
an approaching cold front. Temperatures have warmed into the mid to
upper 80s with dewpoints in the upper 60s across the area
contributing to moderate instability. Modified sounding from ILX
indicates just over 1000 J/kg SBCAPE in place across portions of the
area which initialized well on latest RAP guidance. With minimal CIN
in place, cu field has become increasingly agitated across much of
central IL and far northwest IL with scattered showers and
thunderstorms developing across those areas. Hi-res convective
allowing models continue to show widely scattered to scattered
showers and thunderstorms shifting across the remainder of the
forecast area through the late afternoon and evening hours. Deep
layer shear will likely be a limiting factor for a more organized
severe thunderstorm threat. Values of 15-20kt are in place south of
I-80 though do increase to 25-30 kt as you head northwest corner of
the CWA. With steep low/mid level lapse rates, cannot rule out an
isolated pulse severe wind threat, but overall am not impressed with
the severe setup.
Cold front will sweep across the region this evening and tonight
with winds shifting to the west/northwest and remaining breezy
overnight. Guidance suggests some precip possible immediately behind
the front as the upper wave moves across the region, but soundings
show the low levels quickly drying out behind the front so not sure
it will amount to much.
Cooler and blustery conditions will be in place on Monday. Should
see plenty of sunshine in the dry airmass outside of some scattered
afternoon cold-air stratocu development. Cold airmass will promote
deep mixing with top-of-the-channel winds of 30-35kt resulting in
strong wind gusts at the surface, especially during the afternoon
hours. Expect widespread wind gusts of 30-35 mph during the
afternoon, and cannot rule out a few sporadic gusts pushing 40 mph.
Afternoon highs will only be in the mid to upper 60s.
Deubelbeiss
&&
.LONG TERM...
139 PM CDT
Monday night through Saturday...
Overall this period is on the drier side with seasonally cool
conditions with the best chance Tuesday night into Wednesday. The
deep upper low will only slowly move southward on Tuesday, though
it will get shoved with a bit more earnest later Tuesday and
Tuesday night. Therefore the day should start off as continued
cool and breezy with more sun then clouds, but late in the day
expect cloud cover to increase along with increased chances of
rain showers. These patterns tend to afternoon diurnal increases
in the chance of showers, but core of the cold temperatures aloft
will be moving through overnight into early Wednesday and
therefore would just suggest either clouds or more scattered
showers. As the low moves south a secondary surge of colder air
will move through which could make Wednesday the coolest day of
the week with some chance of showers, especially south of the lake
and across Northwest Indiana where the better chance of
instability showers along with some lake effect/enhancement
possible. There is also some hint of lake convergence later
Wednesday and Wednesday night which could lead to an uptick in
lake effect showers given a decent thermally driven instability
signal. Upper level heights will be increasing during this time
such that the equilibrium levels remain low enough to preclude
any thunder with any possible activity, but there could be some
lake effect continuing into early Thursday.
The general trend is a very slow moderation in the airmass back to
normal levels for late September, though there are some
significant model discrepancies regarding how quickly the low
exits the region. NCEP/GEM ensembles suggest that ridging will
slowly move in but the upper low will become blocked to some
degree. There is some spread in these members, and the EC would
bring continued showers Fri/Sat after the low initially pulls
away. but the farther western track of the EC is not favored at
this time as it is at the western envelope of guidance and even
west of its ensemble mean. Therefore the trend is for generally
dry conditions and a temps near climatological highs in the upper
60s to low 70s with a cool northeast wind into the weekend. Long
range models hint at another warm up beyond this period once the
low does kick out east but this could take a little time.
KMD
&&
.AVIATION...
For the 00Z TAFs...
The concerns with the TAFs are a period of showers later this
evening with a small chance for temporary MVFR conditions this
evening, followed by gusty westerly winds into Monday.
The axis of forcing for bands of scattered showers and storms is
moving east of ORD and MDW early this evening and is gradually
weakening. A couple hours of quietness is expected with winds
gradually veering. The true cold front will push through around
02Z or so and bring an increase in the gustiness of the winds.
Shortly after, a period of showers is expected associated with
upper level forcing...thus cloud bases are expected to remain VFR.
Temporary MVFR visibility is possible though. The confidence in
the showers occurring and the timing, as well as mainly VFR
conditions, is medium-high.
Monday will be the first real gusty autumn day this season with
westerly wind gusts nearing or reaching 30 kt occasionally during
the late morning and afternoon. Confidence in this is medium-high.
A bit challenging to tell if clouds will fill in during the
afternoon which may limit gusts a tad, but they will be VFR if
they occur.
MTF
&&
.MARINE...
139 PM CDT
The first fall-like system will move across Lake Michigan tonight
resulting in a more active period across the lake to start the
week with higher winds and waves expected for several days. Low
pressure across central Canada will send a strong cold front
across Lake Michigan tonight. As the low sinks south toward Lake
Superior Monday, a high pressure ridge across the plains will
extend eastward across the Ohio River Valley. A seasonally strong
pressure gradient coupled with a warm lake will easily result in
westerly winds to 30 kt, and even some occasional gale force
winds, most notably Monday and Monday night. The low will only
slowly sink southward through the Great Lakes through midweek.
During this time winds will shift to more northwesterly but will
still remain in the 20-30 kt range through early Wednesday. The
wind field appears on the stronger side then that normally seen
for waterspout development, but several guidance sources suggest
that as the low nears and begins to pull away midweek that there
could be better convergence of the wind field across southern Lake
Michigan and support waterspouts. Depending on how quick the low
pulls out, an extended period of northerly winds may continue
elevated waves on the south half of the lake. High pressure will
bring a calmer period late week into the weekend.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...Small Craft Advisory...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 7 PM
Tuesday.
Small Craft Advisory...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 10 PM Wednesday.
&&
$$
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Area Forecast Discussion
National Weather Service Marquette MI
756 PM EDT SUN SEP 25 2016
.SHORT TERM...(This evening through Monday)
Issued at 409 PM EDT SUN SEP 25 2016
12Z raobs/latest wv imagery and RAP analysis show hi amplitude
pattern dominating NAmerica featuring deep upr trofs in the plains
and over the Cndn Maritimes arnd an upr rdg over the Great Lks/NW
Ontario. Potent shrtwv lifting nnewd thru the Plains trof is moving
toward Lk Winnipeg with 12hr h5 hgt falls aprchg 100m. Mstr surge in
the warm conveyor belt ribbon ahead of this feature under h85 sw
winds up to 40 kts/sharp pres gradient btwn attendant sfc lo pres in
nrn Manitoba/attendant cold fnt in the plains and sfc hi pres over
Quebec and New England advected 12Z pwats up to about 1.75 inches
over INL/MPX, 250-300 pct of normal. Showers on the ern flank of
this mstr ribbon are impacting mainly the central zns despite drier,
stable airmass shown on the 12Z GRB/APX raobs closer to the sharp
upr rdg axis that has kept the far ern cwa dry. Dry slotting
following the warm conveyor belt has resulted in a band of partial
clrg fm the MN Arrowhead into far nw WI. Looking farther to the w,
there is a pronounced cool pool and plenty of lo clds over the nrn
Plains spreading into MN under the upr trof/behind cold fnt, with
12Z h85/7 temps at Bismarck, ND, down to 4/-2C. The 12Z h85/925 nw
winds at Bismarck were about 50/45 kts and are aiding the strong
caa.
There are a number of fcst concerns in the short term, mainly pops
and winds that wl accompany the passage of the warm conveyor belt
mstr ribbon/sfc cold fropa.
Late this aftn/tngt...Axis of deep mstr/deep lyr qvector cnvgc under
the warm conveyor belt are fcst to shift w-e acrs the cwa thru this
evng, exiting the far e arnd 06Z. Since the showers unstream have
become less wdsprd, wl fcst no hier than likely pops. Mucapes no
more than about 250 j/kg under this warm conveyor belt wl support no
more than isold TS. Dry slotting in the wake of the warm conveyor
belt/cold fropa wl diminish the pops as early as this evng over the
w and may actually bring some brief clrg as obsvd this aftn right
behind cold fropa over MN. But then more backwash mstr/lo clds wl
surge into the area later tngt in the strengthening cyc w flow
behind the fropa. The most wdsprd lo clds and some showers wl impact
mainly the hier terrain of the w with arrival of sharper trof
axis/some upslope wind component. h85 temps falling to about 4C wl
add a lk effect component to the pcpn as well.
Mon...Sharp, slowly veering wsw to wnw cyc flow under slow moving
trof axis/area of deep lyr qvector cnvgc associated with closed lo
driftng thru Ontario just n of Lk Sup wl bring nmrs/even wdsprd lk
enhanced showers to mainly the nw half of the cwa. Although no sharp
pres rise center that would aid an isallobaric component to the wind
is fcst to follow the trof axis, h925 winds up to 40 kts under the
thermal troffing wl support wind gusts aprchg advy criteria at
exposed locations over the Keweenaw Peninsula by later in the aftn.
As the winds veer a bit more toward the w over the ern cwa, waves
are fcst to build sufficiently to cause a hi swim risk in the
beaches of Alger County late in the day. Fortunately, the wx
conditions wl likely discourage swimmers.
.LONG TERM...(Monday night through Sunday)
Issued at 246 PM EDT SUN SEP 25 2016
Focus in the long term continues to be on a low pressure system that
will be occluding over or just N of far northern Lake Superior Mon
evening. The low will linger in the vicinity of the far northern
lake until Tue morning when it will start a slow move to eastern
Upper MI by 00Z Wed. The system moves S of the area Tue night, with
SFC and upper ridging moving in from the NW on Wed.
Main significant impacts will be strong winds near/over Lake
Superior and resulting high waves. Certainly will be seeing plenty
of rain, but not a worrying amount.
Models agree quite well with the track/strength/timing, but some run
to run variability still exists, so the wind forecast will continue
to need fine-tuning. Expect the strongest winds (at least in the
long term) on Monday evening with WNW gusts to 45mph along Lake
Superior over the western U.P. and over much of the Keweenaw. NW-N
winds will gust 35-40mph near Lake Superior for the rest of Mon
night through Tue. Winds will diminish Tue night into Wed.
Winds/waves will lead to dangerous swimming conditions on Lake
Superior, as well as beach erosion (especially along eastern Lake
Superior). No need for a beach hazards statement as temperatures
will be below criteria and it will be rainy.
Lake enhancement will occur as 850mb Temps will be 1-4C from Mon
into early Wed, which when combined with deep cyclonic flow and
upslope forcing will lead to lots of rain near Lake Superior and
more scattered showers well inland. Winds will favor WNW flow area
Mon night, NW-N flow areas Tue, N-NE flow areas Tue night, then
diminishing chances in north central Upper MI Wed morning as NE flow
remains while ridging increases. Should easily see over an inch of
rain Mon night and Tue over the higher terrain of the NW and a
quarter to half inch elsewhere near Lake Superior...under a quarter
inch south central. Tue night into Wed should add another quarter
inch or less of QPF...highest over the higher terrain of the north
central.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 755 PM EDT SUN SEP 25 2016
The arrival of some drying following cold fropa will lead to a
period of VFR conditions at KIWD/KCMX this evening, and IFR
conditions at KSAW will improve to VFR overnight. An increase in low-
level moisture will then bring a return of MVFR conditions at KIWD
late this evening, at KCMX before 06Z, and at KSAW toward sunrise.
Conditions may fall further to IFR at KIWD and perhaps at KCMX Mon
morning as shra increase in coverage. Winds will also become
increasingly gusty during Mon with the stronger winds at KCMX where
gusts will reach up to around 35kt in the aftn.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 409 PM EDT SUN SEP 25 2016
Sse winds that will gale force over portions of the e half of the
lake will diminish w to e this evening/tonight along with an
approaching cold front/weakening gradient. Maintained going gale
warning into late tonight for the far e section of the lake as
terrain enhancement may focus stronger winds in this area. A more
widespread w gale to 35-40 kts will develop over Lake Superior on
Mon under the tightening pres gradient/increasing instability behind
a lo pres trof passage. Opted to upgrade the gale watch to a warning
for this event. With the slow approach of hi pres, these strong
winds will diminish later Tue into Wed. This hi pres will then bring
light winds to end the week.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning until 4 AM EDT Monday for LSZ267.
Gale Warning from 5 PM Monday to 5 AM EDT Tuesday for LSZ265-266.
Gale Warning from 11 AM EDT /10 AM CDT/ Monday to 8 AM EDT /7 AM
CDT/ Tuesday for LSZ162-240>242-263.
Gale Warning from 2 PM Monday to 5 AM EDT Tuesday for LSZ243-244-
264.
Lake Michigan...
None.
&&
$$
SHORT TERM...KC
LONG TERM...Titus
AVIATION...Rolfson
MARINE...KC
Area Forecast Discussion
National Weather Service Raleigh NC
905 PM EDT SUN SEP 25 2016
.SYNOPSIS...
A cold front will move into northern South Carolina and stall
this evening and overnight. High pressure will build south into our
region from New England tonight. The front will return north as a
warm front late Monday as a cold front approaches from the west.
&&
.NEAR TERM /OVERNIGHT/...
As of 905 PM Sunday...
A band of moisture in the lowest 8k ft of the atmosphere underneath
a mid/upper level ridge will result in a deck of low clouds over
most of central NC overnight. The exception will be the far southern-
southwest sections where skies may remain partly cloudy.
Most of the convective allowing models as well as successive runs of
the HRRR suggest scattered showers in vicinity of the Triad late
this evening into the overnight hours. Based on current moisture
profile and upper air analysis, moisture appears too shallow and
synoptic lift virtually non-existent to suggest anything more than a
slight chance PoP for the western counties through the night. May
see pockets of fog over the western and southern counties though
dense fog not anticipated at this time.
Overnight temps will vary from the upper 60s over the southwest to
near 60/lower 60s over the northeast.
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
As of 245 PM Sunday...
Monday will be a murky day as hybrid CAD is expected to develop over
the western Piedmont as a warm/moist advection pattern sets up
between the surface and 850 mb. This occurs as the low level ridge
axis begins to shift east and the next cold front approaches the
Appalachians from the west. Expect the moisture profile further
increase though the day, except for the far eastern zones were some
drying will linger with the ridging. As a mid level trough and the
cold front approach the mountains late, the associated lift and
upslope easterly flow generate areas of rain. This will aid in
locking in the hybrid CAD over the damming region. This pattern will
persist overnight with rain likely in the west, spreading east into
the rest of central NC overnight. We will cap of POP in the high
chance category in the SE Coastal Plain through 12Z/Tue as they will
be farther away from the approaching trough and cold front through
then. Highs Monday from the lower 70s NW to mid 80s south. Lows
Monday night 65-70. QFP of 0.25 to 0.50 forecast for the NW with
less than 0.10 in the SE through 12Z/Tue.
&&
.LONG TERM /Tuesday through Sunday/...
As of 330 PM Sunday...
Tuesday through Wednesday night: A mid/upper low will settle
southward across the Great Lakes on Tuesday, with an associated cold
front moving into central NC Tuesday... before stalling across
eastern portions of central NC Tuesday night. Given sufficient
moisture advection in advance of the cold front, PW`s increasing to
around 1.75", we should see scattered to numerous showers and some
storms on Tuesday into Tuesday evening with potentially even some
localized minor flooding in urban areas/poor drainage areas. With
regard to a severe threat, instability still looks to be weak to
(maybe) modest (with the NAM more robust with its instability).
Deep shear of around 20 to 30 kts is expected. The best height falls
and stronger winds are expected to remain to our north though,
yielding poor mid level lapse rates. Thus, any severe threat will
remain low. However, as noted in the day 3 convective outlook from
SPC, we still could see a few strong to potentially severe storms
with the main threat from damaging winds. High temps on Tuesday are
expected to be generally be in the upper 70s to lower 80s. Lows
temps, with the front stalling across eastern/southeastern half of
the area are expected to range from the mid to upper 50s nw to the
mid 60s se.
The deep mid/upper low will continue to slowly sink
south/southeastward into the Ohio Valley region on Wednesday, with
the mid level flow across our area becoming parallel to the
lingering front. As the mid/upper low approaches, an area of low
pressure is expected to form along the stalled front and track
north/northeastward across central NC, allowing for a continued
chance for showers and some storms on Wednesday into Wednesday
night, with the best chance across the eastern half of the area.
Highs Wednesday are expected to range from the the mid to upper 70s
north to around 80 south/southeast. Lows Wednesday morning are
expected to range from the mid to upper 50s north/northwest to the
lower 60s southeast.
Thursday through Sunday: Forecast confidence is low for this period
of the medium range, with uncertainty about what will happen with
the deep mid/upper low expected to be near the Southern Appalachians
to start the period. The GFS lingers the mid to upper low just to
the north of the area late week, before it lifts off to the
northeast over the weekend. Meanwhile, the latest ECMWF retrogrades
it westward and northward to around IN/IL by 12Z Sunday, allowing
the front to dissipate across our area. The GFS on the other hand
allows the front to shift to the east of the area allowing for below
to near normal temps for the remainder of the period, and dry
conditions generally by Friday. The GFS has been more consistent
with the medium range ensemble guidance. Thus, plan to stay closer
to the GFS (which is wetter than in previous days through Thursday
thank to the GFS now not being as progressive as it past runs).
&&
.AVIATION /00Z MONDAY THROUGH THURSDAY/...
As of 809 PM Sunday...
MVFR/IFR conditions at KRDU, KINT, and KGSO will likely lower to
IFR/LIFR overnight. VFR conditions currently at KFAY, in the
vicinity of the boundary, and KRWI, where some drier air has been
filtering down the east coast and into northeastern areas of the
state. Some uncertainty exists as to whether IFR CIGS expand back
into these areas, though this seems most likely at KRWI. IFR
conditions will hold through Monday at the Triad sites, where
wedging will be slowest to erode, with some improvement to MVFR at
KRDU/KRWI, and VFR at KFAY.
Looking beyond 00Z/TUE, CIGS again will lower with areas of rain and
fog in the west, with an increasing chance of rain and fog in the
east. IFR to MVFR CIGS and VSBYS are expected Monday night into
Tuesday.
Conditions are expected to improve Wednesday and Thursday.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Badgett
NEAR TERM...WSS
SHORT TERM...Badgett
LONG TERM...BSD
AVIATION...30/Badgett
Area Forecast Discussion
National Weather Service Charleston WV
1048 PM EDT SUN SEP 25 2016
.SYNOPSIS...
High pressure shifts east tonight. A cold front will cross Monday
with showers and thunderstorms. Another cold front passes
Wednesday and Wednesday night followed by a closed upper level low
moving in.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 1045 PM Sunday...
Not much change for the front tomorrow, but did tweak dew points
and RH to better match obs which the HRRR picked up on.
Previous discussion follows...Models are in good agreement with a
cold front moving rapidly eastward across the area Monday. The
front will reach the Ohio River by early afternoon and in the
mountains by evening. Even with the speed of the system, models
have a combination of decent dynamics and pooling of moisture to
near 2 inches along the front. Thus, a band of showers and
thunderstorms is expected to accompany the front. However, QPF
amounts will only be on the order of a quarter to half an inch,
thanks to the speed of the system. SPC continues to outline a
marginal risk of severe weather, and will continue this in the
Hazardous weather product. Models also have a prefrontal band of
convection forming Monday afternoon along and east of the I79
corridor. Not too certain about an organized area of convection
there, so will go with scattered convection there in the moist and
unstable air; ahead of the frontal band of convection. Convection
will then ramp down fairly quickly in the west behind the front by
end of period...with even some sunshine by later afternoon. Milder
tonight with increased moisture and southerly winds picking up
late, especially in the west. Highs Monday will still reach into
the 80s ahead of the front.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
As of 315 PM Sunday...
Continuing from the near term forecast, the cold front should move
quickly through the mountains, and take the trailing POPS with
it. Closed low drops south through the Great Lakes...with a lobe
in the cyclonic flow and a cold front developing along the Ohio
Valley. The bulk of the frontogenesis will exist in the
southeastern half of the CWA ahead of the upper level
lobe, keeping these two forcing features separate as they arrive
Wednesday. Dropping low level temperatures and 1000-500mb
thicknesses signify a wholesale airmass change with the broad
closed low over the area.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 315 PM Sunday...
Operational GFS, in a bit of a surprise, has now trended towards
the operational ECMWF with the closed low aloft oscillating around
over the eastern CONUS. Ensemble members still lean towards an
quicker exiting open wave aloft...but the GFS ensemble mean
changes from 00Z to 12Z look to be coming more in line with the
aforementioned operational long term models. From a sensible
weather standpoint, this typically results in a more off than on
precipitation scheme and a temperature forecast that can end up
cooler than the guidance numbers suggest. For the time of year,
nothing seems out of the ordinary in the forecast based on
seasonal norms, however.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
As of 1045 pm Sunday...
VFR and mostly clear to start with. Should see some IFR
cigs/vsbys return to EKN and likely BKW though may be difficult
to get IFR at other sites due to an approaching frontal system.
The front should move through the area Monday afternoon bringing a
wind shift, gusty winds, showers and thunderstorms and likely MVFR
conditions with localized IFR.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z TUESDAY...
FORECAST CONFIDENCE: Low to Medium
ALTERNATE SCENARIOS: Timing and height of fog and stratus
reformation tonight may vary. Timing of band of convection with
the front Monday may be a bit faster than forecast.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE MON 09/26/16
UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
EDT 1HRLY 23 00 01 02 03 04 05 06 07 08 09 10
CRW CONSISTENCY H H H H H H M M M M M M
HTS CONSISTENCY H H H H H H H H H H H M
BKW CONSISTENCY M M M M M M M M M M H M
EKN CONSISTENCY H H M M M M M M M M M L
PKB CONSISTENCY H H H H H H H H H H H M
CKB CONSISTENCY H H H H H H H M M M M M
AFTER 00Z TUESDAY...
Morning valley fog possible Tuesday through Thursday mornings.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.
&&
$$
SYNOPSIS...JMV
NEAR TERM...JMV/JW
SHORT TERM...26
LONG TERM...26
AVIATION...JW
Area Forecast Discussion
National Weather Service SAN ANGELO TX
1047 PM CDT SUN SEP 25 2016
.UPDATE...
Made a quick update based on temperature trends and precipitation
chances and amounts. Cold front is now south of the forecast area
with north to northeasterly winds in its wake, generally in the
10 to 20 knot range. Latest HRRR and NAM are building rainfall
back over the southern CWA beginning several hours after midnight
continuing through the morning hours. Have adjusted rainfall
coverage per latest HRRR and NAM and QPF per latest WPC guidance.
&&
.PREV DISCUSSION... /issued 704 PM CDT SUN SEP 25 2016/
AVIATION...
/00Z TAFS/
MVFR to IFR conditions prevail across most of the area this
evening. These conditions will continue through the evening and
overnight hours for southern sites. KABI is expected to see
improving conditions by 06Z as drier and cooler air moves in
behind a cold front that is sweeping south across the area.
Showers are expected to persist through the overnight hours as
well as humid air is lifted over the top of the cooler surface air
mass. Conditions will improve slowly tomorrow with VFR conditions
expected during the morning hours at KSJT and KABI, with MVFR
CIGs persisting into the afternoon hours for KBBD/KJCT/KSOA. 20
PREV DISCUSSION... /issued 344 PM CDT SUN SEP 25 2016/
SHORT TERM...
(Tonight through Monday Night)
Most of the next 24 hours looks wet with still potential flooding
across southern and western areas tonight. West Central Texas is
between systems this afternoon as stable conditions prevailed due
to widespread heavy rainfall from last night. Thunderstorms are
developing across north and central Texas as best instability
looks to be along and east of the 1-35 corridor. The upper level
low is located over northwest Mexico, with additional short wave
energy upstream of our area. The best potential for heavy rainfall
tonight will be across the Northern Edwards Plateau on east along
the I-10 corridor toward Junction as MCS activity may develop
around the Rio Grande river and move north toward the southern
third of our area. Also, low level flow will be upslope with some
good 850 MB convergence along with elevated instability. Also, a
cold front moving south will provide some lift too. The moisture
will be plentiful, as PW values will still be 1.5 to 1.75 inches.
Will keep the Flash Flood Watch going through 12Z Monday for
western and southern sections. The heaviest rainfall amounts of 2
to 3 inches are possible across the southern third of the area,
with flash flooding of streams, low water crossings and low lying
areas possible.
For Monday and Monday night, the weather will begin to improve
some mainly across the northern half of the area. Still going with
likely Pops across the south half of the area, with locally heavy
rainfall still possible. The Pops are down to slight chance to
chance Monday night, and a dry forecast across much of the Big
Country. Expect cool temperatures with highs in the 60s to around
70 with northeast winds of 10 to 15 mph. Lows Monday night will be
in the 50s.
LONG TERM...
(Tuesday through Saturday)
Long term is quiet with much more autumn like conditions for the
upcoming week and weekend. Upper level ridge of high pressure will
build across the Southern Plains this week, allowing conditions to
dry out. Temperatures will be much closer to seasonal normals,
with lows in the mid 50s to around 60 and highs in the 70s and
lower 80s. Another weak cold front will arrive mid week, which
will effectively level off temperatures for a few days and keep
the dry weather prevailing.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 74 58 66 54 / 90 70 40 20
San Angelo 74 59 66 54 / 90 70 60 30
Junction 74 64 69 55 / 90 80 70 30
Brownwood 80 61 69 55 / 80 70 40 20
Sweetwater 74 56 65 53 / 90 70 40 10
Ozona 75 59 65 52 / 100 80 70 50
&&
.SJT Watches/Warnings/Advisories...
Flash Flood Watch until 7 AM CDT Monday for Coke-Crockett-Fisher-
Irion-Kimble-Mason-Menard-Nolan-Schleicher-Sterling-Sutton-Tom
Green.
&&
$$
99/99
Area Forecast Discussion
National Weather Service La Crosse WI
312 AM CDT Mon Sep 26 2016
.SHORT TERM...(Today through Tuesday night)
Issued at 312 AM CDT Mon Sep 26 2016
Water vapor imagery along with RAP 500mb analysis showing a deep
trough extending south across MN/IA. At the surface...deep low
pressure around 999mb over southern Ontario with a cold front
extending southward through western Lower MI into Indiana. Cooler
air filtering into the region this morning on westerly winds with
temperatures as of 3 am ranging from the upper 40s to the middle 50s.
For today...deep cyclonic flow with tight pressure gradient will
reside over the region for cooler/blustery conditions. Fairly deep
mixing to 800mb expected to produce wind gusts in the 30-40mph
range out of the west/northwest. Winds will be shy of the need for a
wind advisory but thinking with very saturated ground..some trees
may be susceptible to toppling. May issue a special weather
statement this morning for this concern. Steep lapse
rates/instability also expected to produce a pretty good field of
cumulus and a good chance of showers for areas north of I-94.
Otherwise, look for highs ranging from the middle 50s to the lower
60s.
Winds expected to die down this evening with skies remaining mostly
cloudy across north central WI along with a slight chance of showers.
Skies expected to be mostly clear across the rest of the area.
Looks like a chilly night with lows falling into the 40s.
Deep/cool cyclonic flow continues through Tuesday as mid-level low
closes off and moves southward into the area. Models also showing a
lobe of pv-advection dropping through the region Tuesday afternoon
into Tuesday night, bringing with it a chance for showers. Plan on
highs Tuesday in the upper 50s/lower 60s with lows Tuesday night in
the 40s.
.LONG TERM...(Wednesday through Sunday)
Issued at 312 AM CDT Mon Sep 26 2016
Deep cyclonic flow lingers over the region as the closed low moves
farther southward into Indiana. This will keep a small chance of
showers going across far southwest into central WI. Otherwise...
another slightly cooler than normal day on tap with highs in the 60-
65 degree range.
Thursday through Friday look dry and slightly warmer as the closed
low moves farther into the Ohio River Valley which allows a ridge of
high pressure to build over the region. look for highs in the 65-70
degree range and overnight lows in the middle 40s to the lower 50s.
Latest GFS/ECMWF a bit at odds on how to handle closed low saturday
through Sunday. The GFS maintains ridging across the region while
the last 2 runs of the ECMWF show the low retrograding back toward
the region. For now, went with a consensus which keeps us dry with
highs in the 65-70 degree range/lows in the upper 40 to lower 50s.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1143 PM CDT Sun Sep 25 2016
The back edge of the lower VFR ceilings has worked through both
airports this evening. However, there is another area of mid level
clouds rotating southeast across Minnesota that the 26.03Z RAP
suggests could bring a ceiling back into both airports for a while
overnight. These clouds should clear out before sunrise for a
sunny start to Monday before scattered to broken cumulus form late
in the morning or early in the afternoon. The 26.00Z NAM has
backed off on the amount of moisture available for KRST and no
longer suggests a VFR ceiling will form there Monday afternoon.
The other issue to contend with Monday will be the winds. A pretty
tight pressure gradient will be over the Upper Midwest and with
steep lapse rated developing during the morning this should lead
to gusts of 25 to 30 knots for a good share of the day.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...04
Area Forecast Discussion
National Weather Service Goodland KS
200 AM MDT MON SEP 26 2016
.SHORT TERM...(Today through Wednesday night)
Issued at 200 AM MDT Mon Sep 26 2016
Early morning satellite imagery and RAP upper level analysis shows
large scale ridging in place across the western US, with a trough
over the northern Mississippi River Valley. NW flow aloft is
primarily holding influence across the Central High Plains, with
ridging beginning to build across the Central Rockies. Strong
subsidence/dry layer is is apparent on WV imagery and is centered
across our CWA. At the surface 1027-1028 MB high pressure is in
place over our CWA.
Regarding Frost Advisory this morning: Tds have decreased into the
low to mid 30s and temps have declined to near 40F (upper 30s at a
few locations). We still have another 5hr of radiational cooling,
so it still looks like we are in line for possible frost
conditions across our west a maybe a few isolated locations in our
north and east. How widespread is yet to be seen. Plan is to let
the current frost advisory run it course, and will refresh the
statement with the morning forecast package.
Today-Wednesday Night: Large scale ridging will transition over
our CWA and a very stable/dry air mass will keep conditions dry
through these periods. Rising heights aloft and WAA through the
lower levels should support temperatures trending upwards. This
translates to mid to upper 70s today (near normal) and low to mid
80s Tuesday (slightly above normal). A shortwave rounding the
closed low over the Great Lakes will kick a backdoor cold front
towards the High Plains. This will be a dry frontal passage, but
will trend temps back for Wed by 5F compared to Tuesday. I could
see highs being closer to seasonal values in the 70s, but
consensus is still favoring highs around 80F. Lows will tend to be
in the 40s to near 50F (a few cold spots in the west possibly in
the upper 30s).
.LONG TERM...(Thursday through Sunday)
Issued at 200 AM MDT Mon Sep 26 2016
Dry conditions are expected to persist into the extended period
before precipitation chances return heading into the weekend.
Temperatures remain fairly steady in the 70s to low 80s throughout
the forecast.
At the start of the period, a closed low remains over the eastern
half of the country while a ridge of high pressure centers over the
Plains. The ridge starts to break down some late Thursday into
Friday as it moves eastward ahead of the next upper trough advancing
onto the west coast. There are still some differences with the large
scale pattern, particularly when handling the eastern low. However,
the GFS has slowed down and is coming into better agreement with the
ECMWF for the latter half of the week. This has pushed back the
onset of precipitation for the region, with shower and thunderstorm
chances now returning to the High Plains Friday night and lasting
through Sunday as weak shortwaves move across the area through the
southwesterly flow.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1121 PM MDT Sun Sep 25 2016
VFR conditions forecast for the TAFs. Winds will be light as a
ridge moves over the Tri-State Area. Frost may develop on any
aircraft outdoors late tonight and tomorrow morning.
&&
.GLD Watches/Warnings/Advisories...
KS...Frost Advisory until 7 AM MDT /8 AM CDT/ this morning for
KSZ001-013-027-041.
CO...Frost Advisory until 7 AM MDT this morning for COZ090>092.
NE...Frost Advisory until 7 AM MDT this morning for NEZ079.
&&
$$
SHORT TERM...DR
LONG TERM...JBH
AVIATION...JTL
Area Forecast Discussion
National Weather Service Wilmington NC
451 AM EDT Mon Sep 26 2016
.SYNOPSIS...
A stalled front will waver across the area today. A stronger cold
front will approach Wednesday before slowly crossing the area
through late in the week although timing of this front is highly
uncertain. Cooler and drier weather is expected by the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 330 AM Monday...Progressive flow aloft and at the sfc this
period as witnessed by all models which are in general in good
agreement for this period. The eastward moving mid- level ridge
axis pushes overhead today...and east of the FA tonight. Some
bagginess or weak troffiness upstairs, underneath this ridge, has
lagged behind across the SE U.S. States this past weekend and into
this period. A mid-level trof closes off across the western Great
Lakes by late today, and further deepens as it drops to the
Central Great Lakes by daybreak Tue. In essence, the U.S. east of
the Mississippi River is now under the influence of this upper
closed low. Not quite a cut-off due to the upper westerlies are
still pushing thru this upper feature.
Model are in good agreement with movement of sfc features this
period. A 1025mb centered sfc high over New England this morning,
will ridge across the Carolinas into Ga today. The center of this
high pushes off the New England coast and drops SSE to the
offshore waters from the Mid-atlantic states tonight but still
continues to ridge back across the previously mentioned states. An
inverted sfc trof develops just offshore and parallel to the ILM
CWA coastline tonight. And by Tue daybreak, a cold front
associated with the expansive closed low, dropping SE and reaching
the western Carolinas late tonight.
Initially, the ILM CWA will have to deal with the bkn-ovc stratus
deck at 2k to 3k feet this morning. This deck will become sct-bkn
later today and tonight. As for POPs today, with little or no
progged instability until late tonight, have decided to keep POPs
out of the forecast for daylight Mon. This shown by the latest
RAP and HRRR models. For tonight, will indicate a slow increase in
POPs as the inverted trof offshore develops, along with a weak sfc
low off SC/GA coasts from the dynamics associated with the
bagginess aloft discussed earlier. POPs from this feature and also
increasing POPs from the approaching cold front will be advertised
across the FA. Via latest RH model time height displays across the
FA, plenty of mid and upper level dry air today will mix with the
lower levels and partially scour out some of this low level
stratus. Thus, have stayed close to a consensus for the max/min
temp model mos guidance...with an emphasis of slightly hier, by 1
to 2 degrees, for todays highs.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 400 AM Monday...Amazingly, the models have the general idea
of a closed low dropping south from the Great Lakes and becoming
a cutoff low by the end of this period, with the westerlies
bypassing this upper low by the end of this period. Like spokes on
a bicycle, weak mid-level vorts or S/w trofs, rotating around the
upper low, will occasionally affect the FA this period. More-so
when this upper low drops to the central Appalachians. These
s/w`s will be able to interact with dynamics from the slow moving
sfc cold front moving/slithering across the FA. POPs will be
advertised each day, likely hiest during Tue due to the passage of
the sfc low along the inverted sfc trof just off the coast. With
the cold pool aloft partially reaching the area during the latter
half of this period, increasing the lapse rates and instability,
especially involving the days insolation, the chance for
thunderstorms will exist thruout this period. Leaned toward the
European MOS Guidance over the GFS Mos due to its recent slightly
better performance over the GFS Mos.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 300 AM Monday...Big differences in the extended continue to
cause lowered confidence for late this week. While the guidance all
shows a deep trough closing off across the OH VLY, the evolution
thereafter becomes quite muddled. The ECM continues to be a
strong/slow/west outlier with this feature as it digs into the lower
Appalachians and then actually retrogrades to the NW through
Saturday before finally ejecting late in the wknd. The GFS/CMC are
more in line with a sharp digging through Thursday and then lifting
off to the NE through New England Friday and into the wknd. Although
the ECM has been consistent the last few days, the GFS solution is
still preferred as a retrograde west of the upper low into a +3 SD
ridge seems unlikely. WPC cannot rule out any solution at this time
however, so a blended forecast is preferred with highest weight on
the GFS.
This upper low will determine the passage of a surface cold front
which continues to slow in forecast guidance. Favoring the GFS,
FROPA is now expected early Thursday, with cool and dry weather
expected Fri-Sun. In fact, temps Fri-Sun may fall slightly below
climo for both highs and lows as the first fall-like airmass of the
season advects into the Carolinas beneath Canadian high pressure.
Will note that if the ECM solution verifies, the front won`t cross
until Saturday, leaving much more unsettled weather through the
week, along with continued above normal temperatures.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
As of 06Z...Stalled cold front is draped across NE SC this morning,
with high pressure building down the coast from the NE. Moisture is
pooling along the leading edge of this ridge of high pressure and
behind the front, creating increasing stratus across the area. This
stratus will likely become more widespread overnight, but should
remain at MVFR levels, and no IFR is forecast. Best chance for
persistent stratus will be at the inland terminals, and while
confidence is lower at the coast, have included MVFR at all sites
through dawn. Winds will remain 5-10 kts overnight, highest near the
coast, so no visibility restrictions are expected.
The front will waver across the area again during Monday, with
showers and isolated tstms possible at all terminals. Have not
included any mention of TS in the TAFs attm, but VCSH has been
introduced to all terminals. Winds are expected to rise to around 10
kts, while veering to the SE through the aftn/eve. Any showers will
wane after dark Monday night, with more stratus possible at the end
of this valid period.
EXTENDED OUTLOOK...Chance for SHRA/TSRA each day through
Wednesday, with morning fog/stratus also possible. VFR Thursday
and Friday.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 330 AM Monday...Small craft exercise caution thresholds will
be flirted with today, mainly across the waters from Cape Fear
northward.
Sfc ridging to persist across the local area, extending from the
highs 1025 mb center, in transit from New England to offshore
from the Mid-Atlantic states by Tue daybreak. By Tue morning,
models indicate an inverted sfc trof parallel and offshore from
the Carolina coasts. In all, this means a continued onshore wind
trajectory and with a semi-tightened sfc pg, wind speeds will run
around 15 kt with possible gusts up to 20 kt today, dropping to
10-15 kt tonight. Significant seas will run 2 to 4 ft thru
tonight, except a solid 3 to 4 ft north of Cape Fear and also
south of Murrells Inlet. Both locations away from the influence of
Frying pan Shoals. Wind waves at 4 to 6 periods will dominate with
an underlying 1 to 2 foot ese ground swell at 9 to 10 second
periods.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 400 AM Monday...Will see a veering trend to the winds from
easterly at the start of this period, to south southwest by the
end of this period. Weak sfc low to move along the inverted sfc
trof Tue. The sfc cold front to drop SE at a snail`s pace this
period, reaching the local waters by Thu morning. Wind speeds may
become temporarily northerly up to 15 kt after the low passes by
early wed, otherwise looking at around 10 kt for speeds with the
sfc pg relaxing up until the sfc cold front reaches the coast.
Significant seas will run 2 to 3 ft, possibly and briefly
up to 4 ft at the start of this period due to the passage of the
sfc low. Wind driven waves to dominate thru early Wed with
periods running 4 to 6 seconds. ESE, 1 to 2 foot ground swell
at 9 second periods will become dominate later Wed into early
Thu.
LONG TERM/THURSDAY THROUGH FRIDAY/...
As of 300 AM Monday...Still some uncertainty in the extended with
respect to a frontal passage, but attm expect FROPA to occur
Thursday with W/SW winds around 10 kts becoming NW late. High
pressure will build in behind this front creating a very weak
pressure gradient, so winds across the waters on Friday will
feature highly variable direction with speeds of 5-10 kts. Seas of
2-3 ft Thursday will fall to around 2 ft on Friday thanks to the
weaker winds, and a continuing 2ft/9-10 sec SE swell.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.
&&
$$
SYNOPSIS...JDW
NEAR TERM...DCH
SHORT TERM...DCH
LONG TERM...JDW
AVIATION...JDW
MARINE...
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
425 AM EDT Mon Sep 26 2016
.SHORT TERM...(Today through Tuesday)
Issued at 425 AM EDT MON SEP 26 2016
07z sfc analysis shows a well defined cold front moving into the
western portions of the Ohio Valley. However, in the far eastern
parts of Kentucky high pressure remains in control with mostly
clear skies and light winds. As in the past few nights, this has
allowed for a decent ridge to valley temperature difference.
Specifically, readings vary from the low 70s on the ridges to the
low and mid 60s in the more sheltered spots. Dewpoints, meanwhile,
are in the low to mid 60s while the winds remain light. There are
some mid level clouds around, but for the most part skies for
eastern Kentucky are clear while lowering ceilings are approaching
the state from the northwest. The front shows up well on radar,
too. We can see the showers and thunderstorms rolling northeast
along this boundary as they approach western Kentucky. Again in
the east this night, river valley fog has started to form and
some locally dense spots are anticipated through dawn but likely
clearing out quicker this morning than the past few considering
the inbound clouds and winds likely picking up sooner.
The models continue to settle on a similar solution aloft. They
all take the ridge, that has brought extended summer weather to
the area for the better part of a week, east and flatten it out.
The culprit for this pattern change is an impressive early fall
season closed low/trough plowing into the Great Lakes this
morning. This system brings strong height falls, a dynamic wind
field, and ample mid level energy to the Ohio Valley today,
initially brushing by Kentucky to the north. The best dynamics
associated with this will pass by and through the JKL CWA between
18 and 21Z. Following this, heights will continue to fall as the
parent upper low bottoms out, turns over on itself, and starts to
head south down through the Great Lakes. Given the models`
tandem movement to this more extreme solution will favor a
blended starting point with emphasis on the latest NAM and HRRR
for details. Confidence on the specifics is only average at best
given the sense that the models are still in a state of flux
working to resolve this closed low.
Sensible weather will feature any river valley fog burning off
quickly this morning with early sunshine giving way to increasing
and thickening clouds from the northwest. A band of showers and
thunderstorms are expected to enter northwest parts of the area
by late morning, grow in coverage, and sweep through the rest of
eastern Kentucky by late afternoon. Should enough instability
build up ahead of the convective band a few of the storms could
start to organize and become strong with wind gusts the main
threat. Look for the timing of the front to keep the worst of the
storms from developing until they get east of Kentucky, later
this afternoon, but they will still need to be watched closely.
The clouds and pcpn will keep temperatures in check today with
much of the area not likely to get out of the 70s. Much cooler air
arrives tonight in the wake of the front with some 40s anticipated
by morning, especially in the higher terrain and more open areas.
The valleys should hold up a bit better as the cooler air takes a
bit longer to scour them out. Also, anticipate that northwest
winds through the night and the cloud cover will keep fog to a
minimum - for a change. A full fledged fall day will then unfold
on Tuesday with partly sunny skies anticipated and a quite
noticeable change to the air with temperatures only reaching the
low to mid 70s for highs along with much lower humidities.
Started with the CONSShort/ShortBlend for grid population into
the evening and SuperBlend thereafter to 00z Wednesday. Made some
substantial changes to the terrain derived edit areas and
forecast points early this morning and tonight in the temperature
grids to better reflect ridge and valley differences in a neutral
pattern this morning and a cold air advection one tonight. As for
PoPs - ramped them up for later this morning into the likely
category through the afternoon and then dropped them quickly from
west to east after 00z. This is a bit higher than MOS guidance
matching up better with the MAV numbers rather than the MET.
.LONG TERM...(Tuesday night through Sunday)
Issued at 310 AM EDT MON SEP 26 2016
The models have come into better agreement regarding the upper low
currently over the Upper Mississippi Valley. This low will become
closed off and gradually drop southeast towards our area. At the
start of the extended period, the low is progged to be over the
Great Lakes states and then drop southward and be centered over
Kentucky late Thursday. The low will then meander back into the Ohio
Valley region on Friday before weakening and eventually lifting out
of the area over the weekend. Models still struggle with the lows`
exit over the weekend with the GFS taking the low up through New
England while the ECMWF only lifts it into the Great Lakes. Given
these differences, have opted to stay close to the CR Superblend
solution which lifts the showers and thickest cloud cover north of
the area on Sunday.
In terms of sensible weather, it looks like showers and additional
cloud cover will persist from Wednesday afternoon through Saturday
as the upper low remains over the area. With the additional cloud
cover, afternoon highs will be a bit cooler and overnight lows
shouldn`t be as cold as yesterday`s forecast. The coolest days
appear to be Thursday and Friday with highs only in the upper 60s.
Overnight lows will generally remain in the upper 40s and low 50s
through the period.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 155 AM EDT MON SEP 26 2016
High pressure is losing control of the weather through east
Kentucky as a well defined cold front approaches from the
northwest. Ahead of this, though, VFR conditions will exist for
most areas through mid morning along with light and variable
winds. Patchy valley fog will be around again towards dawn,
probably affecting LOZ and SME with some MVFR BR for a couple of
hours. The cold front will cross into eastern Kentucky by early
afternoon. This will result in increasing chances of showers and
thunderstorms for the remainder of the afternoon and into the
early evening. Best potential will be centered between 18 and 21Z
and the TAFs have been adjusted based on these changing
conditions, with MVFR vis and cig conditions possible at all TAF
sites during this time frame and VCTS a concern for a couple
hours either side. VFR conditions will then return quickly in the
evening from west to east with the winds settling to light and
variable. During the best chances for showers and thunderstorms,
along and with the front, winds will shift from the southwest at
5 to 10 kts to the northwest at similar speeds. Some gusts to 15
and 20 kts can be expected for a few hours accompanying the pcpn,
with higher gusts possible - associated with any storms.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...JVM
AVIATION...GREIF
Area Forecast Discussion
National Weather Service Pittsburgh PA
350 AM EDT Mon Sep 26 2016
.SYNOPSIS...
Showers and scattered thunderstorms can be expected with the
passage of cold front today. More seasonable temperatures are
expected for the rest of the week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Deepening trough over the Great Lakes will push a cold front,
currently analyzed over eastern Indiana, across the Upper Ohio
valley this afternoon. Model consensus on timing is relatively
good between the deterministic models and the hi res short term
guidance. As such, very little adjustment was needed to
categorical probabilities with strengthening support for
thunderstorms as the boundary approaches southwestern PA/northern
WV. This will be where surface instability is likely to be the
highest based on the boundary`s timing, and less cloud cover.
The NAM is the most robust with it`s CAPE/dewpoints compared to
other model guidance, including the RAP and HRRR soundings, which
it tends to overdue in most convective scenarios. However, with
deep layer shear present and at least modest cape of 500j/kg,
some strong to severe storms may be possible which is supported
by the spc marginal risk over the aforementioned region.
Strong southerly flow and sunshine in advance of the boundary
should allow for temperatures to warm above seasonal averages this
afternoon followed by normal low temperatures with the fronts
passage progged to be east of the ridges by midnight.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
Temperature advection will be rather weak on Tuesday with
southwesterly flow expected aloft with the upper trough still
situated over the northern Great Lakes and high pressure present
at the surface. Thus, temperatures were forecast just below
seasonal averages.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Most of this period will be dominated by the closed upper
low...which will dive from Michigan into the central Ohio Valley by
Thursday and linger as a cutoff through at least Friday. Models are
beginning to converge on this scenario, with the lagging GFS finally
coming around. As such, mostly chance PoPs were maintained through
the remainder of the work week for scattered showers. Timing of
shortwaves around the upper low remains tricky at this distance.
Given the upper low representing a pattern change, felt the
SuperBlend temperatures were a bit too high and knocked them back a
couple of degrees early on, keeping daytime values a bit below
climatology.
The upper low should begin to lift out by next weekend as midlevel
heights build over the lower Ohio Valley. This will bring dry
weather back by Sunday, as well as allow temperatures to recover
back to seasonal levels.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
Mostly VFR conditions are forecast through midday. The lone
exception may be near DUJ around sunrise, as some low clouds try
to creep up the ridges on southeast upslope flow. Handling with a
MVFR TEMPO for now but may need to adjust depending on satellite
trends.
Conditions will deteriorate during the afternoon with the approach
and passage of a cold front. A short period of MVFR or even IFR
visibilities in showers or thunderstorms is expected, but timing
remains a bit problematic still. Used VCTS and expect to refine
timing in future updates. Some of the storms may be strong, with
heavy rain and gusty winds.
Behind the front, MVFR ceilings will linger for a few hours into
the evening hours, until drier air sweeps in from the west,
allowing for clearing skies.
.OUTLOOK /MONDAY NIGHT THROUGH THURSDAY/...
The next chance for restriction is expected by Wednesday as upper
level low pressure settles into the area.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...None.
OH...None.
PA...None.
WV...None.
&&
$$
Area Forecast Discussion
National Weather Service SAN ANGELO TX
408 AM CDT MON SEP 26 2016
.SHORT TERM...
(Today and Tonight)
Locally heavy rainfall will remain possible today, mainly from the
Concho Valley and areas south to the I-10 corridor. Street flooding
is the main threat. Precipitable waters remain high in the 1.5 to
2.0 inch category, and some of the showers this morning in
Mcculloch county were efficient rainfall producers of over an
inch, as they moved slowly west toward the Concho Valley. HRRR
and GFS models also indicate a band of showers to move north from
the Hill County toward the Concho Valley late morning. Do not
think the flash flood threat is high, however, as the rainfall
will be spread over a 2 to 3 hour time period. Thus, will let the
flash flood watch expire at 7 AM.
Rain chances will significantly decrease by mid afternoon as drier
air moves in from north to south, and as the upper low over Baja
California moves farther west. Keeping a slight chance of showers
south of the Big Country tonight, with the rain potential of a 1/10
or less will be along the I-10 corridor.
Cool today with highs in the mid 60s to 70. Low clouds should
give way to mid and upper level cloudiness late afternoon/evening.
Northern sections of the Big Country may see some clearing toward
morning. Lows tonight are expected in the mid 50s.
04
.LONG TERM...
(Tuesday through Sunday)
...Dry with Seasonal High Temperatures...
The long term forecast is dry, with afternoon highs very close to
seasonal normals and overnight lows cooler than seasonal normals.
Models this forecast cycle continue to indicate high pressure will
build over the region through mid week. Then, high pressure will
dominate the region through next weekend. Counter clockwise
rotation around a well- developed surface low, across the Great
Lakes region, will continue to push cooler and dryer air into
Texas through at least the end of this week. Thus, flow at the
surface, from the south, doesn`t really return to West Central
Texas until next weekend. So, expect afternoon highs will range
from around 80 to perhaps the mid 80s. With light winds, during
the overnight hours, radiational cooling will help produce lows
cooler than normal, mainly in the 55 to 60 range.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 68 55 73 56 / 30 10 10 5
San Angelo 67 55 73 55 / 60 20 10 5
Junction 68 57 74 57 / 70 40 10 5
Brownwood 70 56 75 56 / 60 20 10 5
Sweetwater 66 55 73 56 / 30 10 10 5
Ozona 66 54 72 56 / 80 40 10 5
&&
.SJT Watches/Warnings/Advisories...
Flash Flood Watch until 7 AM CDT this morning for Coke-Crockett-
Fisher-Irion-Kimble-Mason-Menard-Nolan-Schleicher-Sterling-
Sutton-Tom Green.
&&
$$
Area Forecast Discussion
National Weather Service La Crosse WI
607 AM CDT Mon Sep 26 2016
.SHORT TERM...(Today through Tuesday night)
Issued at 312 AM CDT Mon Sep 26 2016
Water vapor imagery along with RAP 500mb analysis showing a deep
trough extending south across MN/IA. At the surface...deep low
pressure around 999mb over southern Ontario with a cold front
extending southward through western Lower MI into Indiana. Cooler
air filtering into the region this morning on westerly winds with
temperatures as of 3 am ranging from the upper 40s to the middle 50s.
For today...deep cyclonic flow with tight pressure gradient will
reside over the region for cooler/blustery conditions. Fairly deep
mixing to 800mb expected to produce wind gusts in the 30-40mph
range out of the west/northwest. Winds will be shy of the need for a
wind advisory but thinking with very saturated ground..some trees
may be susceptible to toppling. May issue a special weather
statement this morning for this concern. Steep lapse
rates/instability also expected to produce a pretty good field of
cumulus and a good chance of showers for areas north of I-94.
Otherwise, look for highs ranging from the middle 50s to the lower
60s.
Winds expected to die down this evening with skies remaining mostly
cloudy across north central WI along with a slight chance of showers.
Skies expected to be mostly clear across the rest of the area.
Looks like a chilly night with lows falling into the 40s.
Deep/cool cyclonic flow continues through Tuesday as mid-level low
closes off and moves southward into the area. Models also showing a
lobe of pv-advection dropping through the region Tuesday afternoon
into Tuesday night, bringing with it a chance for showers. Plan on
highs Tuesday in the upper 50s/lower 60s with lows Tuesday night in
the 40s.
.LONG TERM...(Wednesday through Sunday)
Issued at 312 AM CDT Mon Sep 26 2016
Deep cyclonic flow lingers over the region as the closed low moves
farther southward into Indiana. This will keep a small chance of
showers going across far southwest into central WI. Otherwise...
another slightly cooler than normal day on tap with highs in the 60-
65 degree range.
Thursday through Friday look dry and slightly warmer as the closed
low moves farther into the Ohio River Valley which allows a ridge of
high pressure to build over the region. look for highs in the 65-70
degree range and overnight lows in the middle 40s to the lower 50s.
Latest GFS/ECMWF a bit at odds on how to handle closed low saturday
through Sunday. The GFS maintains ridging across the region while
the last 2 runs of the ECMWF show the low retrograding back toward
the region. For now, went with a consensus which keeps us dry with
highs in the 65-70 degree range/lows in the upper 40 to lower 50s.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 607 AM CDT Mon Sep 26 2016
Strong northwest winds of 13 to 18 kts with gusts of 22 to 36 kts
are expected at the TAF sites today. The strongest winds will be
across the open areas of southeast Minnesota and northeast Iowa.
Otherwise, a scattered to broken cumulus deck will develop today
with cloud bases around 6 kft. Look for the cumulus deck to
dissipate by early this evening. Winds will also diminish with
the loss of daytime heating. Will have to keep a close eye on the
potential for low level wind shear tonight as surface winds drop
off to around 10 kts.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...WETENKAMP
Area Forecast Discussion
National Weather Service Columbia SC
1053 AM EDT MON SEP 26 2016
.SYNOPSIS...
An upper-level ridge will move off the coast today. A stalled
weak cold front over the northern Midlands will provide a focus
for scattered showers and a few thunderstorms. Another cold front
will cross the area Tuesday night into Wednesday. The air mass
behind this system will bring dry weather and more seasonable
temperatures for the latter half of the week into the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
Weak backdoor front that was pushing through NC earlier seems to
have slowed or even stalled near the NC/SC border in the Pee Dee
region. Stratus clouds will persist for much of the rest of the
morning assisted by low-level moisture from the Atlantic.
Weak upper ridge currently over the area will flatten and shift east
today as a digging upper trough/closed low moves into the Great
Lakes region this afternoon and tonight, driving a cold front into
the mountains this afternoon and slowing its push toward the
forecast area overnight. A band of enhanced moisture with
precipitable water values around 1.7-1.8 inches will precede the
approaching front. The increased moisture combined with surface
heating should support weak to moderate instability this afternoon
with scattered showers and thunderstorms expected along and south of
the stalled diffuse frontal boundary currently over the northern
Midlands. This boundary may serve as a focus for convection but
there is some uncertainty regarding the strength of convergence
given the broad southeasterly flow. The latest SPC HRRR indicating
the best chance for precipitation this afternoon primarily along
the southern Midlands due to a weak upper low over the area.
Overall, will continue mention of chance pops over the entire area
this afternoon.
Temperatures today will again be well above normal in the mid to
upper 80s with overnight lows tonight in the upper 60s.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Tuesday looks to provide the best chance for precipitation across
the forecast area as precipitable water values maximize just ahead
of the cold front with values approaching 1.8-1.9 inches with upper
height falls and moderate instability forecast. The cold front is
slow to push through the forecast area Tuesday afternoon and Tuesday
night as the 500mb flow back more southerly, nearly parallel to the
front as the upper trough amplifies. The front eventually pushes
through on Wednesday as the upper level closed low drops southward
into the Ohio Valley and much drier air pushes into the area from
the northwest with precipitable water values dropping below an inch
by Wednesday evening.
Will carry high chance pops across the forecast area on Tuesday into
Tuesday evening with diminishing pops late Tuesday night as the
atmosphere stabilizes and continue higher pops on Wednesday across
the eastern half of the forecast area with lowering pops through the
afternoon from west to east as drier air filters into the region.
Temperatures will remain above normal with highs Tuesday in the mid
to upper 80s and slightly cooler on Wednesday in the lower to mid
80s. Overnight lows Tuesday night will remain mild in the mid to
upper 60s while temperatures will drop a couple of categories for
Wednesday night with min temperatures in the upper 50s to lower 60s.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
Medium range models are in reasonable agreement in the overall upper
pattern showing a closed low somewhere in the vicinity of the
central Appalachians or eastern Tennessee Valley Thursday which then
slowly migrates northward into the Ohio Valley over the weekend. At
the surface, cooler and drier continental high pressure will build
over the forecast area with precipitable water values well below an
inch. Despite very cold 500mb temperatures around -12C to -16C over
the area Thu/Fri with steep mid level lapse rates, the lack of
moisture should limit or preclude precipitation associated with the
upper low, although expect some cloud cover.
Temperatures during this period will feel much more seasonable with
near normal temperatures. Highs will be in the upper 70s to lower
80s and overnight lows will be in the mid to upper 50s.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
Back door front appears to have pushed south into the NE FA and
stalled. Even south of the front, moist low levels and an E to SE
boundary layer flow promoting development of stratus and some fog,
with MVFR TO IFR conditions persist at the terminals until around
16Z-17Z, then becoming VFR.
Back door front expected to remain NE of our terminals, and
eventually become diffuse or drift north as a warm front ahead of a
cold front approaching from the NW. Meanwhile, upper and surface low
to drift NW towards the lower SC coast today. Daytime heating and an
onshore flow to provide potential for scattered showers/isolated
thunderstorms this afternoon, mainly S FA. Will mention VCSH at
DNL/AGS/OGB. Other convective activity along or ahead of the
approaching front late today/this evening appears will remain north
of the terminals. Moist low levels suggests deteriorating conditions
on tap again late tonight.
EXTENDED AVIATION OUTLOOK...Stratus/fog possible late Monday
night/early Tuesday morning. Chance of showers and thunderstorms,
and associated restrictions, Tuesday/Tuesday night. No impacts to
aviation expected Wednesday afternoon through Friday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service State College PA
1055 AM EDT Mon Sep 26 2016
.SYNOPSIS...
A cold front will move through quickly later this afternoon and
early tonight. After a dry day or two, the forecast becomes rather
wet with a cut off upper low .
&&
.NEAR TERM /THROUGH TONIGHT/...
Considerably amount of clouds stuck in the ridge-valley system of
central Pennsylvania this morning. Sunny to the west and sunny to
the east and here I am, stuck in the clouds with you. A nice early
season cold air damming (CAD) event. For the enthusiasts out
there, the 1000 and 925 theta-e contour show this quite nicely
this AM as does the HRRR/RAP dew point fields. All our clouds are
in the gradient between the warmer air to our southwest and the
cooler drier air to our northeast.
I used the HRRR to texturize the clouds a bit and to better time
the frontal rain headed our way. The coarse GFS/GEFS have too
much light rain too fast. The real front and frontal clouds are
well back in Ohio. Most of the eastern half of central PA should
remain a rain free zone until later this evening.
Showers will arrive in the west later this afternoon and the HRRR
implies some enhanced echoes suggesting some modestly organized
thunderstorms along the line of showers. But the weaken in central
PA due to the CAD event. Pretty stable to the north and east.
The HRRR has chance showers with a narrow cold frontal rainband by
18Z and central PA around 21Z reaching Harrisburg an hour to two
either side of 00Z. The HRRR simulates what looks like a narrow
cold frontal rainband which I timed above. The HRRR also shows
the weak evolution of a wideband back in the cold air later this
evening in central PA. This implies two shots of enhanced
rainfall. The wide cold frontal band does not clear
Harrisburg/York/Lancaster until after midnight as it grows in size
and intensity.
The GEFS too shows similar timing of maximum rainfall periods just
to diffuse. It clears out our light rain by 0600 UTC tonight.
The air behind the front should actual be quite dry and conditions
will improve over night west to east. Precipitable water values
drop about -1sigma below normal overnight behind the front.
&&
.SHORT TERM /TUESDAY/...
All the rain should be gone well before sunrise and our PW values
should be well below normal. Some strong winds to mix down so
should be a breezy day and on the cool side of normal along with
very dry air. Thus it should be a pleasantly cool early autumn
day.
There is not real anticyclone behind this system. But the winds
should diminish as we stabilize in the late afternoon and early
evening.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Should be relatively quiet weather Tuesday night into Wednesday.
But the cyclone and developing cut-off to our west and the
boundary along the front to our southeast will impact our weather
by Wednesday.
PoPs should creep up in southeast Wednesday due to the frontal
boundary. The deep cut-off low to our west will increase shower
risk in western PA Wednesday afternoon. And by Thursday the big
cut-off will likely bring us very cool and showery weather for a
few days.
Previous: The mid week period will bring the large upper level
low through the Great Lakes and down into the Ohio Valley. The low
will slowly progress eastward with model PWATS increasing through
the latter half of the week. Couple this with the Southwesterly
flow and will allow for an increase of POPS Through the second
half of the week and into the weekend. This will make the forecast
a little milder at night and slightly cooler in the day, but very
nearly normal. Have kept up with the overall trend of increasing
POPs for the latter half of the week and into the weekend. The
upper low is currently progged to lift northeast, but probably not
until then end of the long term period.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
Mostly VFR about the region. Some low and mid clouds stuck in the
mountains of central Pennsylvania this morning. These clouds may
break up but they will likely linger as broken deck over some
areas. Breaking up is hard to do.
The real front with the potential rainfall is currently racing
across Ohio. We tried to time the onset of the rain and cessation
of the rain based on our mesoscale model, the HRRR. Rain should be
a quick 1-3 hour window in most western areas in the 21 to 03Z
timeframe depending on how far west the airport is.
Rain will take until well after dark to reach KMDT and KLNS and
will be gone well before sunrise.
As the rain and showers come in MVFR and patchy IFR. There could
be some isolated thunderstorms in the western half the State.
Things clear and dry out fast. IFR/MVFR fog and low clouds will
not hold for very long and MVFR should break out fast everywhere a
few hours either side of 11Z.
Outlook...
Tue...No sig wx expected.
Wed...Showers/cig reductions possible late.
Thu-Fri...Sct showers/cig reductions possible, esp w mountains.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Dangelo
NEAR TERM...Grumm
SHORT TERM...Grumm
LONG TERM...Dangelo/Ceru
AVIATION...Grumm
Area Forecast Discussion
National Weather Service Goodland KS
706 AM MDT MON SEP 26 2016
.UPDATE...
Issued at 701 AM MDT Mon Sep 26 2016
The frost advisory for early this morning has been allowed to
expire as temperature are expected to rapidly rise out of the 30s
and into the 40s following sunrise.
&&
.SHORT TERM...(Today through Wednesday night)
Issued at 200 AM MDT Mon Sep 26 2016
Early morning satellite imagery and RAP upper level analysis shows
large scale ridging in place across the western US, with a trough
over the northern Mississippi River Valley. NW flow aloft is
primarily holding influence across the Central High Plains, with
ridging beginning to build across the Central Rockies. Strong
subsidence/dry layer is is apparent on WV imagery and is centered
across our CWA. At the surface 1027-1028 MB high pressure is in
place over our CWA.
Regarding Frost Advisory this morning: Tds have decreased into the
low to mid 30s and temps have declined to near 40F (upper 30s at a
few locations). We still have another 5hr of radiational cooling,
so it still looks like we are in line for possible frost
conditions across our west a maybe a few isolated locations in our
north and east. How widespread is yet to be seen. Plan is to let
the current frost advisory run it course, and will refresh the
statement with the morning forecast package.
Today-Wednesday Night: Large scale ridging will transition over
our CWA and a very stable/dry air mass will keep conditions dry
through these periods. Rising heights aloft and WAA through the
lower levels should support temperatures trending upwards. This
translates to mid to upper 70s today (near normal) and low to mid
80s Tuesday (slightly above normal). A shortwave rounding the
closed low over the Great Lakes will kick a backdoor cold front
towards the High Plains. This will be a dry frontal passage, but
will trend temps back for Wed by 5F compared to Tuesday. I could
see highs being closer to seasonal values in the 70s, but
consensus is still favoring highs around 80F. Lows will tend to be
in the 40s to near 50F (a few cold spots in the west possibly in
the upper 30s).
.LONG TERM...(Thursday through Sunday)
Issued at 200 AM MDT Mon Sep 26 2016
Dry conditions are expected to persist into the extended period
before precipitation chances return heading into the weekend.
Temperatures remain fairly steady in the 70s to low 80s throughout
the forecast.
At the start of the period, a closed low remains over the eastern
half of the country while a ridge of high pressure centers over the
Plains. The ridge starts to break down some late Thursday into
Friday as it moves eastward ahead of the next upper trough advancing
onto the west coast. There are still some differences with the large
scale pattern, particularly when handling the eastern low. However,
the GFS has slowed down and is coming into better agreement with the
ECMWF for the latter half of the week. This has pushed back the
onset of precipitation for the region, with shower and thunderstorm
chances now returning to the High Plains Friday night and lasting
through Sunday as weak shortwaves move across the area through the
southwesterly flow.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 512 AM MDT Mon Sep 26 2016
VFR conditions will continue through the TAF period at KGLD and
KMCK. High pressure will remain over both terminals, and winds
will remain 10kt or less from a westerly direction through the TAF
period.
&&
.GLD Watches/Warnings/Advisories...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...LOCKHART
SHORT TERM...DR
LONG TERM...JBH
AVIATION...DR
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
944 AM EDT Mon Sep 26 2016
.UPDATE...
Issued at 944 AM EDT MON SEP 26 2016
Continuing to monitor a line of showers and thunderstorms moving
into the western and central portion of the state this morning.
This line remains collocated with the frontal boundary location.
However, of note, winds ahead of this line and ahead of the actual
surface front are already shifting in direction. While much of the
CWA is seeing light SW winds, winds are quickly switching to a
more NE direction just along our western CWA border ahead of the
line of precip. At first glance it was thought that the frontal
boundary may be outrunning the precip, which would bring about the
demise of the initial line but could cause some redevelopment
across our CWA a little earlier than originally forecast. However,
upon second glance it appears as though the frontal placement is
in tact with the precip, but the wind shift could just be the
result of an outflow of the line or perhaps a secondary weak
trough axis.
Either way, this will be something to watch as it will likely
cause a weakening of the initial line as it continues to push
eastward, especially considering low stratus is now outrunning the
initial line as well. That being said, some redevelopment may
occur ahead of the line, across our CWA where warmer temps and
clearer skies still exist, but latest Hi-RES CAM models all
support only scattered convection across our CWA throughout the
day. And interestingly enough, most of them are also lining up
with the thought of the initial line continuing to lose strength
as it pushes eastward as well, showing the line continuing to
shear out through 18Z and scattered convection popping up across
eastern KY during this time. Will continue to monitor as we head
through the next few hours in case any updates to POPs need to be
made, but if this idea holds together, results of this line could
be quite benign with some locations missing out on rain all
together.
A new forecast package was sent out with this update to remove
morning fog wording. The latest observations for temps, dew
points, and winds were also loaded into the near term forecast to
make sure it was well on track with current conditions. All
changes have been published and sent to NDFD/web.
UPDATE Issued at 715 AM EDT MON SEP 26 2016
Another quick update to fine tune temps, dewpoints, and sky cover
through the next few hours based on current obs and trends. These
have been sent to the NDFD and web servers.
&&
.SHORT TERM...(Today through Tuesday)
Issued at 425 AM EDT MON SEP 26 2016
07z sfc analysis shows a well defined cold front moving into the
western portions of the Ohio Valley. However, in the far eastern
parts of Kentucky high pressure remains in control with mostly
clear skies and light winds. As in the past few nights, this has
allowed for a decent ridge to valley temperature difference.
Specifically, readings vary from the low 70s on the ridges to the
low and mid 60s in the more sheltered spots. Dewpoints, meanwhile,
are in the low to mid 60s while the winds remain light. There are
some mid level clouds around, but for the most part skies for
eastern Kentucky are clear while lowering ceilings are approaching
the state from the northwest. The front shows up well on radar,
too. We can see the showers and thunderstorms rolling northeast
along this boundary as they approach western Kentucky. Again in
the east this night, river valley fog has started to form and
some locally dense spots are anticipated through dawn but likely
clearing out quicker this morning than the past few considering
the inbound clouds and winds likely picking up sooner.
The models continue to settle on a similar solution aloft. They
all take the ridge, that has brought extended summer weather to
the area for the better part of a week, east and flatten it out.
The culprit for this pattern change is an impressive early fall
season closed low/trough plowing into the Great Lakes this
morning. This system brings strong height falls, a dynamic wind
field, and ample mid level energy to the Ohio Valley today,
initially brushing by Kentucky to the north. The best dynamics
associated with this will pass by and through the JKL CWA between
18 and 21Z. Following this, heights will continue to fall as the
parent upper low bottoms out, turns over on itself, and starts to
head south down through the Great Lakes. Given the models`
tandem movement to this more extreme solution will favor a
blended starting point with emphasis on the latest NAM and HRRR
for details. Confidence on the specifics is only average at best
given the sense that the models are still in a state of flux
working to resolve this closed low.
Sensible weather will feature any river valley fog burning off
quickly this morning with early sunshine giving way to increasing
and thickening clouds from the northwest. A band of showers and
thunderstorms are expected to enter northwest parts of the area
by late morning, grow in coverage, and sweep through the rest of
eastern Kentucky by late afternoon. Should enough instability
build up ahead of the convective band a few of the storms could
start to organize and become strong with wind gusts the main
threat. Look for the timing of the front to keep the worst of the
storms from developing until they get east of Kentucky, later
this afternoon, but they will still need to be watched closely.
The clouds and pcpn will keep temperatures in check today with
much of the area not likely to get out of the 70s. Much cooler air
arrives tonight in the wake of the front with some 40s anticipated
by morning, especially in the higher terrain and more open areas.
The valleys should hold up a bit better as the cooler air takes a
bit longer to scour them out. Also, anticipate that northwest
winds through the night and the cloud cover will keep fog to a
minimum - for a change. A full fledged fall day will then unfold
on Tuesday with partly sunny skies anticipated and a quite
noticeable change to the air with temperatures only reaching the
low to mid 70s for highs along with much lower humidities.
Started with the CONSShort/ShortBlend for grid population into
the evening and SuperBlend thereafter to 00z Wednesday. Made some
substantial changes to the terrain derived edit areas and
forecast points early this morning and tonight in the temperature
grids to better reflect ridge and valley differences in a neutral
pattern this morning and a cold air advection one tonight. As for
PoPs - ramped them up for later this morning into the likely
category through the afternoon and then dropped them quickly from
west to east after 00z. This is a bit higher than MOS guidance
matching up better with the MAV numbers rather than the MET.
.LONG TERM...(Tuesday night through Sunday)
Issued at 310 AM EDT MON SEP 26 2016
The models have come into better agreement regarding the upper low
currently over the Upper Mississippi Valley. This low will become
closed off and gradually drop southeast towards our area. At the
start of the extended period, the low is progged to be over the
Great Lakes states and then drop southward and be centered over
Kentucky late Thursday. The low will then meander back into the Ohio
Valley region on Friday before weakening and eventually lifting out
of the area over the weekend. Models still struggle with the lows`
exit over the weekend with the GFS taking the low up through New
England while the ECMWF only lifts it into the Great Lakes. Given
these differences, have opted to stay close to the CR Superblend
solution which lifts the showers and thickest cloud cover north of
the area on Sunday.
In terms of sensible weather, it looks like showers and additional
cloud cover will persist from Wednesday afternoon through Saturday
as the upper low remains over the area. With the additional cloud
cover, afternoon highs will be a bit cooler and overnight lows
shouldn`t be as cold as yesterday`s forecast. The coolest days
appear to be Thursday and Friday with highs only in the upper 60s.
Overnight lows will generally remain in the upper 40s and low 50s
through the period.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 725 AM EDT MON SEP 26 2016
High pressure is losing control of the weather through east
Kentucky as a well defined cold front approaches from the
northwest. Ahead of this, though, VFR conditions will exist for
most areas through mid morning along with light and variable
winds. Patchy valley fog will be around again towards dawn,
possibly affecting LOZ and SME with some MVFR BR for an hour or
two. The cold front will cross into eastern Kentucky by early
afternoon. This will result in increasing chances of showers and
thunderstorms for the remainder of the afternoon and into the
early evening. Best potential is centered between 18 and 21Z and
the TAFs reflect this, with MVFR vis and cig conditions possible
at all TAF sites during this time frame and VCTS a concern for a
couple hours either side. VFR conditions will then return quickly
in the evening from west to east with the winds settling to light
and variable. During the best chances for showers and storms,
along and with the front, winds will shift from the southwest at 5
to 10 kts to the northwest at similar speeds. Some gusts to 15 and
20 kts can be expected for a few hours accompanying the pcpn, with
higher gusts possible - associated with any storms. VFR conditions
and light winds follow into Tuesday morning with fog less of an
issue due to lingering clouds, a drier air mass, and light
northwest winds.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...GREIF
LONG TERM...JVM
AVIATION...GREIF
Area Forecast Discussion
National Weather Service Raleigh NC
1030 AM EDT MON SEP 26 2016
.SYNOPSIS...
A quasi-stationary front across southwestern NC will return north as a
warm front today as a cold front approaches from the west. The cold front
will move very slowly southeast through the area Tuesday and into Wednesday.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1030 AM Monday
High pressure off the New England coast extends into east-central NC
this morning, with an east-southeasterly flow banking moisture up
against the mountains and ceilings varying from below 1000ft in the
west to 3000-4000 ft in the east. Persistent convection around the
Charlotte Metro area has shown signs of waning in the past couple of
hours, likely owing to a relaxation of the nocturnal LLJ and weaker
isentropic accent. This precip, along with addition showers
expected to trigger within an instability axis running up the
foothills this afternoon, will have less moisture and forcing to
work with as the mid-level flow carries it eastward. Thus, we will
run with POPs varying from 30-40% in the western Piedmont to 20%
near US-1.
Temperatures continue to be a tough call, especially in the western
Piedmont, as a southeasterly wind has developed, but the moisture
(stratus) is somewhat trapped horizontally but the mountains and
vertically by a weak CAD-like inversion (per 12z GSO raob). However,
850/925mb temps are around 16-18C over the southern and western
portions of the Piedmont, so the airmass will support strong warming
if/when clouds breaks. We`ve blended in some HRRR and LAMP guidance
to help with the uncertainty and possible gradient, which yields mid
70s northeast to mid 80s southeast.
Tonight:
Sfc cold front is forecast to slip east of the mountains, but remain
west of the forecast area through daybreak Tuesday. Upper support is almost
non-existent, so expect convection to be tied closed to the low-level
moisture convergence along the front and thus expect bulk of shower
activity to remain across the NC Foothills and Western Piedmont.
Lows in the mid 60s to lower 70s.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
As of 415 AM Monday...
Low-level frontal zone stretched across central NC will slow down,
potentially temporary stall across the area as the closed upper low
over the Great Lakes and attendant deep upper trough begins to digs
south into the Ohio Valley and southern Appalachians. Axis of 1.6-
1.7" PWAT attendant to the front will be centered across the area
Tuesday afternoon and Tuesday night with numerous showers and
scattered thunderstorms expected to move slowly south-southeastward
across the area. Weak mid-level lapse rates should again limit
destabilization and thwart severe threat. We could however see some
locally heavy rain and minor flooding with models suggesting
rainfall amounts widespread rainfall amounts of a half inch to an
inch, with locally higher amounts of 1 to 1.5 inches possible. The
front should settle slowly across eastern portions by late Tuesday
evening/night with rain chances beginning to taper off from nw to se
by daybreak Wednesday.
Highs in the mid 70s northwest to lower 80s se. Lows Tuesday night
60 to 67.
&&
.LONG TERM /Wednesday through Sunday/...
As of 345 AM Monday...
Forecast confidence remains below average due to an atypically
complex synoptic pattern expected to evolve over North America
mid/late week. The 00Z GFS/ECMWF both indicate that an upper level
low amplifying over the Great Lakes early this week will dig
southward through the OH valley and cut-off in vicinity of the TN
Valley/Mid-Atlantic through mid/late week as an expansive upper
level ridge builds over the eastern 2/3 of North America, though
disagreement persists w/regard to the precise evolution of the cut-
off low. Broadly speaking, long range guidance supports above normal
chances for cloud cover/precipitation and slightly below normal
temperatures mid/late week, though further details (i.e. precip
amount/timing and perhaps severe wx potential) remain difficult to
ascertain at this time. -Vincent
&&
.AVIATION /12Z MONDAY THROUGH THURSDAY/...
As of 740 AM Monday...
Southerly moist upglide atop a quasi-stationary frontal boundary that
extends across the western piedmont will support a chance of showers
primarily over the western and central piedmont this morning. The front
will retreat northeastward as a warm front between 15 to 21z. IFR to MVFR
ceilings over the piedmont will lift to VFR with the passage of
the warm front.
Moisture pooling ahead of a cold front moving into the
mountains will also support a small chance of showers and possibly
a thunderstorm late in the afternoon/early evening with rain chances
increasing overnight with sub-VFR ceilings as the front approaches
the NW Piedmont.
Looking beyond the 24 TAF Period: A cold front will move very slowly
se through the area Tuesday and into the day on Wednesday. Showers
and storms with associated periods of sub-VFR conditions are
expected to accompany the front. Conditions are expected to improve
to VFR from northwest to southeast Wednesday-Wednesday night as
drier air filters into the area.
During midweek, a rather unsettled pattern is expected to evolve as
a deep upper low sags southward from the Great Lakes into the
Central Appalachians.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...CBL
NEAR TERM...CBL/BS
SHORT TERM...CBL
LONG TERM...Vincent
AVIATION...CBL
Area Forecast Discussion
National Weather Service Blacksburg VA
915 AM EDT Mon Sep 26 2016
.SYNOPSIS...
High pressure will remain wedged against the east side of the
Appalachians today. Meanwhile a cold front will be moving east
across the Ohio Valley. This front will pass through the area
tonight bringing showers and thunderstorms.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 915 AM EDT Monday...
Made some minor adjustments in temperatures utilizing surface obs
and trends, then shaped towards Lamp guidance for late morning
into this afternoon. Increased pops in the east for this morning
to capture prefrontal convection highlighted on HRRR and HiResW-
arw-East. Cold front will move east...approaching the appalachians
this afternoon and move across our area tonight. There is a
Marginal Risk for severe storms across West Virginia into
Alleghany highlands in Virginia this afternoon and evening, the
main threat from strong damaging wind gusts. More changes later
this morning.
As of 430 AM EDT Monday...
High pressure will remain wedged against the east side of the
Appalachians today...east-southeast wind flow resulting in
upslope cloudiness drizzle and fog. West of the Appalachian
divide, downslope wind flow will result in a lot less cloud cover
with little or no precip until the arrival of a cold front later
in the day.
A surface cold front extends south from the Great Lakes into the
western OH/TN valleys. This front is forecast to move
east...approaching the appalachians this afternoon. An axis of
instability just ahead of the front will fuel scattered to
numerous showers and thunderstorms, some of which will be rather
strong as they move into West Virginia during the peak heating
hours of the afternoon. There is a Marginal Risk for severe storms
across West Virginia this afternoon and evening, the main threat
from strong damaging wind gusts.
These storms are expected to weaken as they cross the mountains
this evening, encountering the stable airmass, cool wedge, on the
east side of the mountains. Never the less, still anticipate a
period of moderate to heavy showers this evening and early tonight
with potential for a half inch of rain as the front moves over and
east of the Blue Ridge. Forward progress of the front is expected
to slow per the upper level support lagging, models trending
toward a slower solution with respect to the eastward push of the
front with time.
Temperatures today will be relatively mild in spite of the
cloudiness with highs in the 70s. Any sun, and we could easily test
80. Slower frontal progress also means lingering warmth tonight,
especially east of the Blue Ridge where we are looking at another
night with minimums above 60.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 400 AM EDT Monday...
The Cold front will continue to slowly cross the region from west to
east early Tuesday in advance of a closing upper low rotating
through the Great Lakes into midweek. Synoptic scale models continue
to trend slower with the frontal passage, and differ widely with the
ultimate stalling location of the boundary. For now, have slowed the
progression of said boundary by a few hours out of respect to the
ECMWF and GFS solutions. All in all, expect to see impacts in the
form of broken to overcast skies and scattered showers mainly east
of the Blue Ridge Mountains through the day Tuesday, with a rumble
of thunder or two possible in the far east if enough daytime heating
is allowed, which for now seems doubtful.
Boundary likely to stall just southeast of the area Tuesday night.
Models begin trending differently at this point, with smaller scale
solutions allowing the boundary a bit more progression toward the
coast and introducing cold air advection more rapidly, while the
GFS/ECMWF have it sliding back NW as the low begins to slip down
into the mid-Atlantic Wed/Thr. With this uncertainty, have re-
introduced POP/QPF values a bit earlier in the east, but continue to
keep temperatures trending cooler into midweek with cloudcover and
cold air advection in play, especially to the west. Appears enough
progged 850 mb cooling out west under a period of clearing and light
winds to result in some of the coolest lows of the season with
low/mid 50s east, and 40s west including perhaps a few 30s deepest
valleys outside of any fog by early Wednesday.
Any drying between the frontal passage and the closed low will be
short lived as the flow quickly backs aloft Wednesday in response to
the upper low dropping south and deeper moisture to the east
shifting back inland. This will bring a combination of increasing
shower chances Blue Ridge east by afternoon with weak surface low
pressure to the east, and showers along the western slopes along the
leading edge of the deeper moisture axis on the front of the upper
low. Kept pops mostly low end chance most sections with less
southern Blue Ridge for now where expecting a gap between the two.
Otherwise becoming partly/mostly cloudy with highs mostly 60s
mountains to low/mid 70s east.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 400 AM EDT Monday...
Trend toward a cloudier/wetter and much cooler scenario continues at
least to start the period with models swinging a strong upper low
from the Ohio Valley early Thursday morning southeast into/and
around the region into early next weekend. This would allow for some
degree of deeper moisture with the residual front along the coast to
get swung back inland around this feature, espcly by weeks end per
latest GFS. However, model spread remains rather large with earlier
ECMWF farther to the southwest with this feature, while the 12z GFS
much stronger now with the cold pool about directly overhead
Thursday into Friday night before the upper low lifts out. Latest
ensembles were closer to the earlier weaker 00z runs excluding the
Euro with a much weaker upper system keeping most showers to the
north and east. Since great uncertainty plan to just continue trend
of including more chance pops Wednesday night into Friday night, at
least for diurnally driven showers under the cold air aloft. Should
finally see this slow moving system weaken and lift out during the
weekend with drier air aloft spilling in.
This will allow for a return to dry weather for later Saturday into
Sunday although clouds may linger given possible redevelopment of
another low level wedge under leftover weakness aloft at this point.
Temps likely to be below normal under very cool air aloft with highs
60s to low 70s through Friday with potential 50s at elevation
pending clouds. Some rebound likely during the weekend as highs
slide back into the 70s overall. Lows also chilly, mostly 40s to
low/mid 50s, with possibly even a few 30s again deeper valleys early
Thursday if a period of more clearing develops early on.
&&
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
As of 800 AM EDT Monday...
Poor flight conditions will persist today per cool moist airmass
banked up against the east side of the Appalachians. Low clouds
cover much of VA/NC with ifr/lifr conditions right along the Blue
Ridge per clouds intersecting the terrain. In addition to the low
cigs, areas of drizzle and fog will restrict visibility, esp along
the Blue Ridge where MVFR-IFR vsbys are likely.
The cool wedge will begin to erode from the southwest late in the
day per approach of a cold front from the Ohio Valley. Cigs are
forecast to improve into MVFR category after 18Z. Strong cold
front will push into WV/KY by late afternoon with a line of
showers and a few thunderstorms expected to accompany the front,
diminishing as it reaches the KBLF and KLWB TAF sites. Have
included showers for all of the taf sites this evening and
overnight as the front slowly works its way across the mountains.
Extended aviation discussion...
The front will slow in its forward progression across the Piedmont
Tuesday, so showers and a few thunderstorms may linger across that
region as a result. Initially to the west conditions will improve
with mostly VFR to MVFR conditions within this time frame. During
midweek, a rather unsettled pattern is expected to evolve as a
deep upper low sags southward from the Great Lakes into the
Central Appalachians. This will keep variable clouds, MVFR cigs,
and periods of -SHRA across the region through much of the period.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...PM
NEAR TERM...KK/PM
SHORT TERM...JH/JM
LONG TERM...JH
AVIATION...PM
Area Forecast Discussion
National Weather Service SAN ANGELO TX
639 AM CDT MON SEP 26 2016
.AVIATION...
/12Z TAFS/
IFR ceilings south of I-20 will improve to VFR by late afternoon
as drier air moves in from the north. Temporary visibilities down
to 2 miles in heavy rain showers are likely this morning over all
terminal except KABI.
&&
.PREV DISCUSSION... /issued 408 AM CDT MON SEP 26 2016/
SHORT TERM...
(Today and Tonight)
Locally heavy rainfall will remain possible today, mainly from the
Concho Valley and areas south to the I-10 corridor. Street flooding
is the main threat. Precipitable waters remain high in the 1.5 to
2.0 inch category, and some of the showers this morning in
Mcculloch county were efficient rainfall producers of over an
inch, as they moved slowly west toward the Concho Valley. HRRR
and GFS models also indicate a band of showers to move north from
the Hill County toward the Concho Valley late morning. Do not
think the flash flood threat is high, however, as the rainfall
will be spread over a 2 to 3 hour time period. Thus, will let the
flash flood watch expire at 7 AM.
Rain chances will significantly decrease by mid afternoon as drier
air moves in from north to south, and as the upper low over Baja
California moves farther west. Keeping a slight chance of showers
south of the Big Country tonight, with the rain potential of a 1/10
or less will be along the I-10 corridor.
Cool today with highs in the mid 60s to 70. Low clouds should
give way to mid and upper level cloudiness late afternoon/evening.
Northern sections of the Big Country may see some clearing toward
morning. Lows tonight are expected in the mid 50s.
04
LONG TERM...
(Tuesday through Sunday)
..Dry with Seasonal High Temperatures...
The long term forecast is dry, with afternoon highs very close to
seasonal normals and overnight lows cooler than seasonal normals.
Models this forecast cycle continue to indicate high pressure will
build over the region through mid week. Then, high pressure will
dominate the region through next weekend. Counter clockwise
rotation around a well- developed surface low, across the Great
Lakes region, will continue to push cooler and dryer air into
Texas through at least the end of this week. Thus, flow at the
surface, from the south, doesn`t really return to West Central
Texas until next weekend. So, expect afternoon highs will range
from around 80 to perhaps the mid 80s. With light winds, during
the overnight hours, radiational cooling will help produce lows
cooler than normal, mainly in the 55 to 60 range.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 68 55 73 56 / 30 10 10 5
San Angelo 67 55 73 55 / 60 20 10 5
Junction 68 57 74 57 / 70 40 10 5
Brownwood 70 56 75 56 / 60 20 10 5
Sweetwater 66 55 73 56 / 30 10 10 5
Ozona 66 54 72 56 / 80 40 10 5
&&
.SJT Watches/Warnings/Advisories...
Flash Flood Watch until 7 AM CDT this morning for Coke-Crockett-
Fisher-Irion-Kimble-Mason-Menard-Nolan-Schleicher-Sterling-
Sutton-Tom Green.
&&
$$
99/99/04
Area Forecast Discussion
National Weather Service Buffalo NY
509 PM EDT MON SEP 26 2016
.SYNOPSIS...
A cold front will move across the region into the evening...and the
colder air in its wake will generate some lake effect rain showers
northeast of the lakes on Tuesday morning. A slow moving storm
system to our south could then keep somewhat unsettled weather over
our region through much of the rest of the week.
&&
.NEAR TERM /THROUGH TUESDAY/...
A cold front will steadily push across the forecast area through
this evening. At 5 pm, radar shows showers associated with this
boundary are organized in a north-south line roughly between
Buffalo and Rochester. This line of showers will continue to move
east through this evening, with showers expected to exit east of
the cwa and into Central New York around midnight. Recent runs of
the HRRR have this timed well, however consensus QPF among high
res guidance appears overdone...especially across the Western
Southern Tier where thunderstorms have stayed to the south in
Pennsylvania. These may reach into New York through early
evening, but chances for thunder elsewhere appears limited.
Satellite shows a significant dry slot in the wake of the front,
especially to the south away from lake influences. This will
promote at least partial clearing late this evening and early
overnight, but there will be more weather to contend with. Mother
Nature will shift gears from synoptic to mesoscale as 850mb temps
falling back to around 5C will establish moderately unstable
conditions over the lakes. This will be accompanied by a weakly
capped, low sheared environment that will still have some synoptic
moisture to further support the heat and moisture transfers off
the warm lake waters. We often see a dry environment that can not
be moistened enough by lake processes, but this case will not be
one of them.
The most pronounced lake response will be northeast of lake Erie
where a near maximum fetch will encourage the development of a band
of lake effect rain that will extend across the Buffalo metro area
after 09z. This band should drift north to the Northtowns and
towards the Falls by daybreak. The placement of this band is a
little further north than most of the mesoscale guidance packages,
taking into account the thermally induced low level backing of the
flow which is often discounted by guidance. Off Lake Ontario...the
240 degree flow will result in a shorter fetch and less impressive
organization. The associated showers will be directed across
northern Jefferson County to the Thousand Islands region.
Temperatures tonight will drop back through the 50s, with some 40s
anticipated for the Southern Tier.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
Tuesday night into Wednesday morning is shaping up to be a
relatively quiet and mainly dry period for Western and North-
Central New York. A large upper level low will be continuing its
gradual descent across the central Great Lakes, while drier air
wrapping across the southeastern flank of this low will continue
to remain overhead much of the lower Great Lakes. This, along with
a synoptically unfavorable position in the left entrance region of
an exiting upper-level jet streak will keep things dry Tuesday
night. The cool and relatively dry air aloft should also allow
temperatures to fall into the 40s Tuesday night.
Temperatures will rebound into the 70s along the lake plains on
Wednesday, aided by strengthening downsloping southeasterly flow,
with 60s across the higher elevations. While this southeasterly flow
should initially keep things dry for much of the day on Wednesday,
the main upper level low is currently progged to drop south towards
the Ohio valley, while a secondary low off the Mid-Atlantic is
shunted off to the northeast. This will open up much of Pennsylvania
and Western New York to a long southeasterly fetch of Atlantic
moisture that will isentropically lifted along the northeastern
flank of the main low over Ohio, in turn generating an increasing
number of showers across much of the forecast area as we move from
Wednesday evening into Thursday. As a side note, the strengthening
east-northeast flow in the lower levels on the northern edge of the
surface flow will likely produce a considerable swath of lake-
enhanced rains just to our north across the Greater Toronto Area
Wednesday night into Thursday morning.
The increasing cloud cover and influx of maritime air into the
region will produce more mild temperatures Wednesday night, with
lows in the upper 40s to lower 50s, while the widespread clouds will
keep readings in the low to mid 60s Thursday. Showers will likely
persist through the end of the week as the upper low stalls out over
the region. The persistent mild air will keep lows in the 50s
Thursday night.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
This period will be dominated by a large cut-off low which is
generally forecast by medium-range global models to meander from the
Ohio Valley north and east across the eastern Great Lakes then
shifting off the coast of New England as an open trough by early
next week. Among the 12z runs the ECMWF remains the slower of the
model solutions. The cut-off low will draw a broad slug of Atlantic
moisture westward across the tri-state region to the eastern Great
Lakes and upper Ohio Valley where it will interact with multiple
vorticity maxes circulating around the low. Each of these vort maxes
should force a swath of rain showers shifting from east to west
across the region. 12z NAEFS standard anomalies of PWAT for the
Friday into the weekend timeframe are running between 1.5 and 2
deviations above normal which means moisture will be plentiful for
numerous periods of rain showers. WPC 48-hour QPF guidance for 00z
Friday into 00z is showing a large swath of 1-2+ inches of rainfall.
Forecast-wise this requires an extended period of chance range POPs
and cloudy to mostly cloudy skies running Friday through Sunday only
tapering to slight chance by Monday when the low is forecast to be
shifting east of New England. Highest confidence is on Friday across
the Southern Tier closest to the center of the cut-off low. As model
agreement becomes better aligned as this event gets closer and
confidence increase expect that POPs will be increased further with
finer detail in timing of swathes of showers. The high level of
Atlantic moisture streaming across the region should ensure mild
seasonable temperatures with highs in the mid to upper 60s and lows
only slipping back into the 50s.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
A cold front crossing the region will bring widespread showers
through early evening. Ceilings will drop to MVFR levels along
the front across the western counties, with a brief periods of IFR
cigs possible.
Overnight, ceilings will quickly rebound to VFR levels as skies will
at least partially clear in the wake of the front. Lake effect
clouds and showers will develop to the northeast of Lakes Erie and
Ontario around 09z through 15z on Tuesday, but should be north of
most of the TAF sites, although there may be some lowering
ceilings and showers at KIAG during this timeframe.
Outlook...
Tuesday and Tuesday Night...Mainly VFR. Areas of MVFR/IFR in lake
effect rain showers northeast of Lake Erie.
Wednesday through Saturday...VFR/MVFR with a chance of showers.
&&
.MARINE...
A cold front will cross the area with widespread showers through
this evening. Colder air following the front will be more capable
of mixing to the warmer lake surfaces. A stronger pressure
gradient following the front and the colder air will produce gusty
winds tonight and Tuesday, resulting in Small Craft Advisories
along the Lake Erie nearshores, and along the eastern end of Lake
Ontario. The Lake Ontario conditions will improve as winds become
southeasterly late Tuesday, but wind will remain rather strong
from the south to southwest along the Lake Erie shores. Although
conditions will not be ideal, there is a potential for some
waterspouts along a convergence band which is expected to develop
on Lake Erie late tonight and Tuesday.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory until 5 AM EDT Wednesday for LEZ040-041.
Small Craft Advisory until 5 PM EDT Tuesday for
LOZ045.
&&
$$
SYNOPSIS...RSH/WCH
NEAR TERM...APFFEL/RSH/WCH
SHORT TERM...WOOD
LONG TERM...SMITH
AVIATION...APFFEL/WCH
MARINE...APFFEL/WCH
Area Forecast Discussion
National Weather Service State College PA
524 PM EDT Mon Sep 26 2016
.SYNOPSIS...
A cold front with a line of showers will sweep through the region
overnight. A developing deep cut-off low will bring cool cloudy
weather into the region late Wednesday and into early this
weekend. The deep cold air should trigger showers Thursday through
most of the coming weekend before it slowly begins to lift out.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Forecast has not changed much in the HRRR and NCEP models. The
front is a bit slower and there is a lead band of showers/isolated
thunder in western PA now.
The cold air damming in central areas has held on well and the
cool stable air remains to the east.
Showers will move into western areas over the next few areas with
main area to the west still just entering PA. The unforecast lead
band in southwest PA could bring a shower to Clearfield-Cambria
and Somerset in the next 1-3 hours well ahead of the larger scale
band of rain.
HRRR pretty much, the the GEFS, has a 3 hour window for most areas
of rain and exists all the rain 0.10 or more rainfall to our east
in the 06 to 09Z rain. Some lingering light stuff in extreme east
probably a bit later than 09Z.
Dry air behind front should clear it out. Do not expect lingering
low clouds and fog behind this front.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
Sunny breezy day some clouds especially in mountains. Probably the
best day of the week. No real anticyclone behind front due to
building trough to our west and wave along the coast.
But -1sigma PW and 6-10C 850 mb temperatures imply a pleasant
early autumn day. It could be breezy a few hours after sunrise and
the winds should diminish in the late afternoon.
My bet is the statewide is the best day of the week as the cut-off
is going to make things ugly by Wed-Thu.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Big change in the weather pattern will set up with a long wave
trough and a cut off low dropping down over the Eastern U.S. and
several days with rain in the forecast.
Tuesday night into Wednesday morning will see some drying and
seasonable temperatures behind the cold front. But a large upper
level low is dropping southeast across the Great Lake Region. By
Wed afternoon the upper low is over Ohio and moisture is being
pulled back north along the Eastern Coast into PA. Chances for
rain showers will increase Wed afternoon with periods of rain
showers likely Wed night into Thurs night as the low continues
south into Western VA. Friday the low begins to shift back to the
northwest continuing the wet pattern into Saturday. Models hint
that Central PA may be dry slotted for a bit friday afternoon and
night. Upper low begins to lift northeast Saturday into Monday
with gradually decreasing POPs. Lower Susq will be driest over the
weekend and dry Monday with increasing chances farther north
across the higher terrain of the northern tier where chances will
linger into Monday morning. Temperatures will be a little milder
at night but cooler during the day with clouds and periods of
showers thereby averaging around normal.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
Southerly flow ahead of a cold front has brought widespread MVFR
with areas of IFR to the region. Expect continued reduced
conditions throughout the evening and into the overnight before
drier air begins moving in behind the cold front. Improving
conditions will develop just after midnight in the west, but it
will take until morning to for the improvement to reach the
eastern terminals.
Tuesday will become VFR after early MVFR/IFR, though it will be a
breezy day.
Wed should be the last good VFR day before more showery and
cloudy conditions develop later in the week into the weekend
with widespread reduced conditions likely.
Outlook...
Wed...Showers/cig reductions possible late.
Thu-Sat...Sct showers/cig reductions possible, esp w mountains.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Grumm
NEAR TERM...Grumm/Ceru
SHORT TERM...Grumm
LONG TERM...Watson
AVIATION...Grumm/La Corte
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
330 PM MDT MON SEP 26 2016
.SYNOPSIS...
Tropical moisture will continue to stream northward over the
Borderland the next several days. A chance of rain will continue
through Tuesday, and then with instability increasing, isolated
thunderstorms are possible Wednesday through Friday. Cool fall
temperatures on Tuesday will gradually warm back to near normal
Thursday and Friday.
&&
.DISCUSSION...
WV imagery showing upper low now over the central Baja with decent
moisture feed from Tropical Storm Roslyn. PW`s range from about
.70 to .90 across the CWA, so not abundant moisture. Moisture and
stable airmass has created widespread cloudiness, but only a few
areas of light rain are falling. This moisture feed will continue
through Friday. For tonight and Tuesday, cool airmass will persist
with stable airmass not permitting any thunderstorms. For this
period continue scattered showers but had lessened QPF around the
area. Some wind gusts along west slope continuing this evening.
HRRR showing some brief increase again tonight along west slopes
as inversion develops but don`t expect wind advisory levels.
Models showing some warming back to near normal Wednesday through
Friday, so instability increases. Isolated thunderstorms a good
bet all 3 days. Shear profile also begins increasing Thursday and
is more widespread on Friday, so can`t rule out a few
thunderstorms approaching severe (perhaps concentrated west on
Thursday and east on Friday).
Much drier southwest flow kicks in Saturday and Sunday with
approaching Pacific trough moving onshore. Trough reaching the
area Monday and Tuesday may lead to windy days.
&&
.AVIATION...Valid 27/00Z-28/00Z...
P6SM SCT-BKN060-080 with isolated -SHRA BKN050-070 through 12Z then
clouds breaking up to FEW-SCT060-080. Winds generally E to SE
5-15KTS.
&&
.FIRE WEATHER...
Upper low currently over the Baja region will be weakening over the
coming days as upper ridge builds over the western plains. This will
keep a southerly upper level flow over area with southeast surface
winds keeping moisture in place. Best precipitation chances through
midweek will remain west of the Rio Grande with a push to the east
possible Thursday into Friday. Temperatures will begin warming
Tuesday and be near normal by Wednesday through the weekend.
Relative humidities will remain above 20 percent through the week
but start to drop over the weekend as westerly flow brings in much
drier air.
&&
.PRELIMINARY POINT TEMPS/POPS...
El Paso 53 74 58 81 / 30 20 10 20
Sierra Blanca 51 68 53 78 / 30 20 10 10
Las Cruces 50 74 53 79 / 30 20 20 20
Alamogordo 49 77 54 80 / 30 20 10 20
Cloudcroft 38 57 40 64 / 30 20 20 20
Truth or Consequences 49 74 51 77 / 30 20 20 20
Silver City 48 70 51 73 / 30 30 30 30
Deming 48 74 51 78 / 30 20 20 20
Lordsburg 51 72 52 78 / 30 30 20 30
West El Paso Metro 53 74 57 80 / 30 20 10 20
Dell City 50 71 52 81 / 30 10 10 10
Fort Hancock 52 74 58 81 / 30 20 20 20
Loma Linda 46 67 53 78 / 30 20 10 20
Fabens 51 74 56 81 / 30 20 20 20
Santa Teresa 51 74 54 80 / 30 20 10 20
White Sands HQ 52 75 55 79 / 30 20 10 20
Jornada Range 47 76 51 80 / 30 20 10 20
Hatch 52 74 54 79 / 30 20 20 20
Columbus 52 74 54 79 / 30 20 20 20
Orogrande 52 75 56 81 / 30 20 10 20
Mayhill 41 62 43 71 / 30 20 10 20
Mescalero 40 66 42 73 / 30 20 20 20
Timberon 40 63 42 71 / 30 20 20 20
Winston 41 69 44 75 / 30 30 20 30
Hillsboro 45 72 50 77 / 30 20 20 30
Spaceport 48 75 52 78 / 30 20 20 20
Lake Roberts 40 71 47 75 / 30 40 20 30
Hurley 47 71 50 75 / 30 30 20 30
Cliff 47 72 48 78 / 30 40 30 30
Mule Creek 44 72 46 76 / 30 40 30 30
Faywood 45 72 50 76 / 30 30 20 30
Animas 49 74 50 79 / 40 30 20 30
Hachita 46 73 50 78 / 40 30 20 30
Antelope Wells 47 72 51 78 / 40 30 20 30
Cloverdale 46 68 50 76 / 40 30 20 30
&&
.EPZ Watches/Warnings/Advisories...
NM...None.
TX...None.
&&
$$
Hefner/Grzywacz
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
644 PM EDT Mon Sep 26 2016
.SYNOPSIS...
A weak area of low pressure off the southeast coast will lift northeast
tonight and Tuesday. A cold front will pass through from the west
Tuesday night. An area of low pressure over the Great Lakes
Wednesday will move into the mid-Atlantic states Friday and linger
into the weekend.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...D
As of 640 PM Monday, latest trends of surface observations and
satellite showing deep moisture continuing to increase from the
south this evening with good saturation occuring around 850 mb as
weak low pressure moves up the coast in advance of cold front
which should cross the area later tomorrow evening. The latest
15-minute HRRR model data along with the RAP and 4km NAM all
showing precipitation spreading onshore toward morning. Tweaked
the timing of the onset of this precipitation slightly, but still
have high chance PoPs coast tapering to slight chance well inland.
No changes to the forecast temperatures with lows in the mid 60s
well inland to lower 70s coast.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
As of 3 PM Mon...A cold front will approach from the west, while a
weak low lifts NE along the NC coast. Expect decent coverage of
showers and isolated thunderstorms through the day, best chances
along the coast early then shifting more inland in the afternoon.
Better moisture and forcing as cold front and upper trough
approach the region. High res guidance in agreement showing precip
coming in off the water early morning, mainly impacting the
Southern OBX down to the Crystal coast...and adjusted previous
pops accordingly. Will continue to cap pops at high chance with
models backing off slightly from previous runs. Low level
thickness values and cloud cover support highs in the upper 70s to
around 80.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
As of 3 PM Mon...Unsettled through Thu then a bit drier by the
weekend. Did not make significant changes to previous forecast.
Tue night through Thu...The low will depart to the NE Tue Night
however the front will sag into the region Wed and Thu as upr low
drops into the Ohio Valley region keeping decent chc of shra
going...again will cap at 50 percent given uncertainty on coverage
and timing. Temps close to seasonal for late Sept with highs 70s
to lower 80s and lows 60s inland to around 70 beaches.
Fri through Sun...The upr low to the NW will slowly move E or NE
into the weekend. Does look like drier mid lvl air will grad spread
E pushing bulk of the precip offshore Fri into the weekend. Cont
prev fcst of slight pops imd cntrl and srn cst with no pop inland this
period. Highs will be mainly 75 to 80 with lows around 60 inland
to around 70 OBX.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Short Term /through 00Z Wednesday/...
As of 640 PM Monday, increased cloud coverage along with continue
light SE/S winds should limit the development of stratus and fog
overnight. Numerical guidance continues to show widespread lower
ceilings and vsbys but will continue previous trends of forecast a
4000-5000 foot ceilings through the TAF period. Continue to bring
in showers by late morning on Tuesday.
Long Term /Tuesday night through Saturday/...
As of 3 PM Mon...Decent cvrg of shra into Thu with poss some
isold trsa. The precip will lead to a few periods of sub VFR thru
Thu. Drier air will work in from the W Fri with decreasing chc of
shra and mainly VFR.
&&
.MARINE...
Short Term /through Tuesday/...
As of 645 PM Monday, winds generally E/SE across the waters at
5-15 knots with seas of 2-4 feet. As low pressure moves up the
coast, winds will increase to 10-15 knots late generally from the
SE/S. For Tuesday, E/SE winds continue at 10-15 kt with seas
generally 2-4 feet...but could see 5 ft on the outer central
waters by Tue afternoon.
Long Term /Tuesday night through Saturday/...
As of 3 AM Mon...Wind dir will be tricky much of the period. Winds
become more E to poss NE as low lifts NE just offshore late Tue
into Tue night. The low will depart Wed however the front is
expected to stall near of just W of region leading to variable
winds Wed becoming more SW late in week with speeds aob 15 kts.
Seas expected to be in the 2 to 4 foot range thru the period.
There is potential for a bit stronger winds and higher seas assoc
with the low Tue and will have to monitor later model runs.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Beach Hazards Statement through Tuesday evening for NCZ095-103-
104.
MARINE...None.
&&
$$
SYNOPSIS...CQD
NEAR TERM...CTC
SHORT TERM...CQD
LONG TERM...RF/CQD
AVIATION...RF/CTC/CQD
MARINE...RF/CTC/CQD
Area Forecast Discussion
National Weather Service Marquette MI
358 PM EDT MON SEP 26 2016
.SHORT TERM...(This evening through Tuesday)
Issued at 357 PM EDT MON SEP 26 2016
12Z raobs/latest wv imagery and RAP analysis show deep upr troffing
dvlpg over the wrn Great Lks as vigorous shrtwv/closed upr lo that
caused 00-12Z h5 hgt falls up to 220m at GRB digs into the area.
Sharp pres gradient on the srn flank of 996mb sfc lo pres over
Ontario has caused some gusty w winds up to 40-45 mph over the more
exposed wrn cwa, in line with obsvd 12z 3k agl nw wind up to 45 kts
at INL. The 12Z INL raob also shows some deep mstr/nearly moist
adiabatic lapse rates up to about 400mb, and this moist airmass in
concert with the sharp cyc llvl flow and h85 temps falling as lo as
2-3C under the thermal trof on the sw flank of the Ontario lo have
resulted in some nmrs lk enhanced showers over mainly the wrn cwa,
where the llvl winds are presenting a sharp upslope component.
Downsloping nature of the wsw winds farther to the e and deep lyr
qvector dvgc/mid lvl drying have limited the shower coverage to
isold-sct away fm this area.
Main fcst concerns in the short term wl focus on pops/winds
associated with closed lo that is fcst to slide slowly se and to
over ecentral Lk Sup on Tue. The arrival of weakening winds/more
mstr and more unstable lapse rates over the e half of Lk Sup could
result in some waterspouts there late tngt into Tue.
Tngt...As closed lo shifts slowly to the sse and to over far nrn Lk
Sup by 12Z Tue, deeper mstr/qvector cnvgc are fcst to overspread the
entire cwa. Although the more wdsprd lk enhanced showers wl persist
over the wrn cwa with continued sharper upslope winds, the arrival
of some dynamic support and deeper mstr within the llvl cyc flow wl
increase shower coverage over the rest of the cwa. But downsloping
flow wl limit the pops over the se portion of the cwa. Winds thru
this evng wl remain quite gusty over the w under lingering tight
pres gradient/h925 w winds up to 40kts, but the closer aprch of the
sfc lo pres/weakening pres gradient wl cause the winds to diminish
later. Fcst mucapes as hi as 500-750j/kg within a deep convective
lyr featuring narrow, skinny cape and the weakening winds/deep,
sharp cyc flow may allow for a few TS/waterspouts over the e half of
Lk Sup. Since the llvl winds are fcst to remain more wsw near the
lkshore over the e half of the cwa, any deeper convection/
waterspouts wl remain offshore of the e half of Upr MI.
Tue...The closed lo is progged to drift slowly s to to over scentral
Lk Sup by late in the day. Although wind speeds wl diminish under
the grdly flattening pres gradient, lingering deep mstr/cyc flow/
some deep lyr qvector cnvgc wl support continued showers, which wl
be most nmrs-wdsprd over the hier terrain of the nw half with an
upslope flow. Although a downslope flow wl limit pops over the se
half, the closer aprch of the closed lo wl support at least sct
showers there. Since the area of modest mucape up to 500-750 j/kg wl
tend to slide to the ssw with the upr lo track, the threat of TS, as
well as some waterspouts under the weaker winds under the flatter
pres gradient closer to the lo center, wl migrate toward the
nearshore areas fm the Keweenaw e to Whitefish Pt by later in the
aftn.
.LONG TERM...(Tuesday night through Monday)
Issued at 337 PM EDT MON SEP 26 2016
Attention remains focused on the first day or two of the long term
as the closed low shifts out of the area.
Models indicate that the low will be over south central Lake
Superior at 00Z Wed, which is a westward shift from previous runs.
This trend may slightly continue, but would think that models will
have a pretty good handle on the system at this point. The low will
shift to northern Lake Michigan by 06Z Wed, southern Lake Michigan
by 12Z Wed, then gradually shift to central or eastern KY by Thu
afternoon.
As the low shifts through and out of the area, the main hazards will
be gusty winds, high waves/beach erosion, and waterspout potential.
NE winds gusting to 30-35mph will gradually diminish over and near
Lake Superior Tue night into Wed, but winds will increase to 25-
30mph over and along northern Lake Michigan on Wed into Wed evening.
Winds will drive waves up to around 8` over western Lake Superior,
which may result in some minor beach erosion. As for waterspouts,
favored areas will be south central Lake Superior Tue evening and
Tue night then over northern Lake Michigan late Tue night into Wed.
Rain showers will be most focused over north central and western
Upper MI Tue night, transitioning to northern Lake Michigan Wed into
Wed evening as ridging moves in from the NW.
Challenge late in the week is how close does the upper low come to
the area as it moves back to the N from KY. The ECMWF bring it
across central Lower MI and Lake Huron this weekend into early next
week, while the GFS takes it across OH and Lake Erie. The ECMWF
solution brings chances for rain showers Fri through the weekend,
while the GFS confines any precip chances to the far eastern CWA.
With low confidence in the track of the low, stuck with the
consensus blend late week through day 7.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 142 PM EDT MON SEP 26 2016
A moist cyc upslope wnw flow wl bring predominant lo end MVFR
conditions to CMX/IWD this fcst period. IFR conditions are possible
at times, especially at IWD late as the flow veers more to the NW
and increases the overwater trajectory of the air into that site.
The downslope nature of the flow wl allow for hier end MVFR cigs to
prevail at SAW, but even there the cig is likely to drop into the
lower MVFR range by the early mrng hrs on Tue as lo pres now in
Ontario sinks into Lk Sup and draws closer. Gusty winds will also
continue thru this evng, especially at the more exposed CMX location,
where gusts aoa 35 kts are likely. The strongest winds will tend to
diminish later tngt into Tue with the closer approach of the Ontario
lo pres and a weakening pres gradient.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 357 PM EDT MON SEP 26 2016
As a lo pres over Ontario sinks slowly s and over Lake Superior, the
pres gradient over the waters will flatten and cause ongoing w gales
to diminish under 30 kts by mid morning on Tue. There could be some
waterspouts over the e half of Lake Superior late tonight into Tue
night under the slowly passing lo pres. With the slow approach of
trailing hi pres, the winds will continue to slowly diminish later
Tue into Wed. This hi pres will then bring lighter e to ne winds
under 20 kts to end the week.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning until 5 AM EDT Tuesday for LSZ243-244-264>266.
Gale Warning until 11 AM EDT /10 AM CDT/ Tuesday for LSZ162-263.
Gale Warning until 8 AM EDT /7 AM CDT/ Tuesday for LSZ240>242.
Lake Michigan...
None.
&&
$$
SHORT TERM...KC
LONG TERM...Titus
AVIATION...KC
MARINE...KC
Area Forecast Discussion
National Weather Service Blacksburg VA
259 PM EDT Mon Sep 26 2016
.SYNOPSIS...
A cold front will move east tonight into Tuesday across the region
with scattered showers and thunderstorms. A wave of low pressure
moving along this front will stall the convection across eastern
sections of the area on Wednesday, before finally exiting Wednesday
evening into Wednesday night.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 259 PM EDT Monday...
A strong cold front will move east across the region tonight into
Tuesday. An axis of moderate instability just ahead of the front
will fuel scattered to numerous showers and thunderstorms, some of
which could contain heavy rains and gusty winds. Lack of deep-layer
shear and poor mid-level lapse rates will limit severe potential.
These storms are expected to weaken tonight after they cross the
mountains and encounter the cooler stable airmass east of the Blue
ridge. Leaned tonight pops towards the HRRR which captured the
convection best this afternoon.
A period of moderate to heavy showers are possible with convection
this evening into tonight. There is the potential for a half inch of
rain as the front moves over and east of the Blue Ridge. However,
the forward progress of the cold front will slow with the upper
level support lagging overnight. With low level moisture and light
winds expected patches of fog overnight. Low temperatures tonight
will range from the upper 40s in the northwest mountains to the
mid 60s in the Piedmont.
On Tuesday, the cold front will slowly move east across the region
in advance of a closing upper low rotating through the Great Lakes.
Elected to slow down the timing of the frontal passage. Considerable
cloudiness and scattered showers will continue Tuesday, especially
east of the Blue Ridge mountains. An isolated thunderstorm is
possible in the east if enough daytime heating is allowed. The day
two convective outlook supports this with its general thunderstorm
area. High temperatures on Tuesday will vary from the mid 60s in the
mountains to the mid 70s in the Piedmont.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 1230 PM EDT Monday...
At the beginning of this portion of the forecast, a cold front will
be making slow progress eastward through the central and eastern
portions of the forecast area. A wave moving along this front will
stall the activity across the far eastern sections of the area on
Wednesday, finally exiting Wednesday evening.
We also will be watching a slow progression southeastward of a
closed upper low from Wisconsin to either eastern Kentucky or West
Virginia. Showers will be on the increase across the area with the
approach of this system, especially by the time Wednesday night into
Thursday arrives. Steep cold pool lapse rates will allow for decent
shower development. Isolated thunderstorms will be possible thursday
afternoon, mainly east of the Blue Ridge. Models place the freezing
level around around 5000 to 7000 ft AGL across the mountains and
8000 to 10000 ft AGL across the Piedmont. Small hail will be
possible given the expected convective nature of the day, even from
strong showers, and the relatively low freezing levels. Previously
on Wednesday, freezing levels are expected to be about 2000 to 3000
feet higher, thus small hail is less likely, but not impossible, on
Wednesday, especially across western sections, as compared to
Thursday.
Temperatures during this portion of the forecast will turn slightly
cooler as compared to Tuesday, but average within a degree or two
plus or minus of normal conditions for this time of the year.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
As of 130 PM EDT Monday...
The slow moving upper low will continue to impact our forecast into
Friday, however, the trend will be for the low to start heading
north in response to a building upper ridge across the center
portion of the nation. Progressively each day through Sunday, the
concentration of showers will will trend more toward the northern
sections of the forecast area, following the track of the low. While
no thunderstorms are forecast, isolated hail will again be possible
within the stronger showers given a continuation of a relatively low
freezing level through Saturday.
Sunday into Monday, a dry forecast is expected along with moderating
temperatures as the upper ridge strengthens and its axis shifts
eastward. At best some isolated showers may be possible across the
Northern Mountains of North Carolina on Monday where
Temperatures during this portion of the forecast will trend only
slightly milder on average than the early part of the week. While
highs may climb a bit higher, lows are expected to trend slightly
cooler as the diurnal range increases thanks to decreasing dew point
values across the region.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
As of 142 PM EDT Monday...
Poor flight conditions will persist this afternoon into tonight
with cool moist airmass banked up against the east side of the
Appalachians and cold front moving east across the region. Pockets
of low clouds with ifr/lifr conditions persist right along the
Blue Ridge per clouds intersecting the terrain. To the west, the
cool wedge has been eroding ahead of an approaching cold front.
Scattered MVFR showers and thunderstorms have developed this
afternoon in the unstable air ahead of this cold front across the
mountains. The cold front will push east into WV/KY by late
afternoon and into the mountains this evening with a line of
showers and a few thunderstorms. This convection is expected to
diminishing as it reaches the more stable air created by the
wedge. The front will work its way east tonight into Tuesday. The
front will slow in its forward progression across the Piedmont
Tuesday, so MVFR showers and a few thunderstorms may linger across
that region as a result.
Low to medium confidence in ceilings,visibilities and winds
during the taf period.
Extended aviation discussion...
A wave moving along this front will stall the activity across the
far eastern sections of the area on Wednesday, finally exiting
Wednesday evening. Conditions will improve with mostly VFR to
MVFR conditions within this time frame. During midweek, a rather
unsettled pattern is expected to evolve as a deep upper low sags
southward from the Great Lakes into the Central Appalachians. This
will keep variable clouds, MVFR cigs, and periods of -SHRA across
the region through much of the period.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...KK
NEAR TERM...KK
SHORT TERM...DS
LONG TERM...DS
AVIATION...KK/PM