Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/27/16
Area Forecast Discussion
National Weather Service State College PA
1059 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/...
Satellite continues to show cold front moving in Eastern Ohio and
continues to progress eastward. Latest radar shows bands of
showers and isolated thunderstorms moving to the northeast.
Expect showers through Eastern PA from 03Z to 06Z.
HRRR and GEFS has bands dissipating later tonight and as cold air
moves in skies should clear with Dry air behind front. 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 /03Z TUESDAY THROUGH SATURDAY/...
South-southeasterly 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 Tuesday
morning. Any improving conditions after midnight will probably
just set the stage for the development of fog so earlier confidence
in clearing is now not so high.
Tuesday will start with most areas still experiencing MVFR/IFR,
but drier air on a gusty NW breeze will lead to rapidly improving
conditions in the few hours just after sunrise.
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...Ceru
SHORT TERM...Grumm
LONG TERM...Watson
AVIATION...La Corte
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
936 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/...
As of 930 PM Monday, regional radar showing a few showers off the
coast around the Wilmington area. 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 /02Z 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 935 PM Monday, no real changes as winds continues ESE/SE 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
745 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 00Z TAFS through 00Z Tuesday evening)
Issued at 744 PM EDT MON SEP 26 2016
A slow moving low pres system will dominate the Upper Great Lakes
thru Tue. Resulting cyclonic upslope w to nw flow and abundant
moisture will lead to prevailing low MVFR cigs at KIWD/KCMX thru
this fcst period. IFR conditions are possible at times, especially
at KIWD on Tue as the flow veers more to the nw and increases the
overwater trajectory of the flow. At KSAW, the downslope nature of
the flow will allow for higher end MVFR cigs thru the evening, but
the cig is still likely to drop into the lower MVFR range by the
early morning hrs on Tue as low pres now in northern Ontario sinks
to Lake Superior and draws closer. Gusty winds will also continue,
more so at KIWD/KCMX, and especially at the more exposed KCMX
location, where gusts aoa 35kt are likely this evening. Winds will
tend to diminish later tonight into Tue with the closer approach of
the Ontario low 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...Rolfson
MARINE...KC
Area Forecast Discussion
National Weather Service Blacksburg VA
1054 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 1050 PM EDT Monday...
Made some fairly significant changes to pops and weather once
again. As expected pre-frontal activity slowing in its eastward
progression across the eastern parts of the forecast area, but the
more intense activity has moved east of the CWA border. With the
wave of low pressure riding along the front from the southeast
states, do not expect this activity to make much further eastward
progress overnight, so will continue to hold onto likely to
categorical pops east of the Blue Ridge overnight.
Back to the west, the front is near an LWB-BLF-JFZ line, along
which a broken line of showers persists with an isolated
thunderstorm. Have increased pops across this area as a result.
After this passes by, it is likely that fog and drizzle will
develop across areas west of the Blue Ridge overnight before a
better northwest takes effect after 14Z Tue.
No significant changes to T or Td readings this hour.
As of 800 PM EDT Monday...
Initial line of pre-frontal convection slowly moving east of the
Blue Ridge. Thunderstorms and heavy rain showers likely for the
next couple of hours from KLYH to KROA to KDAN. Redevelopment of
convection back along the front in eastern WV. HRRR seems to have
a good handle on the overall progression and development of
convection through the evening, although the placement may be a
bit off, namely too far north. Heavier convection developing
across northwest/north central NC may cutoff convection back to
the north somewhat. At any rate, will continue with likely to
categorical pops across much of the area through 06Z...tapering to
chance thereafter. Temperatures were running several degrees
cooler in rain cooled areas west of the Blue Ridge and were
adjusted downward. Otherwise, no significant changes were needed.
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 MONDAY/...
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 /03Z TUESDAY THROUGH SATURDAY/...
As of 800 PM EDT Monday...
Generally poor aviation conditions expected through much of the
TAF valid period. A strong cold front was moving through the
region this evening with a line of pre-frontal convection marked
by heavy rain producing thunderstorms, MVFR cigs, and MVFR-IFR
visibilities. Convection was redeveloping along the front back in
WV at this hour as well. Showers and thunderstorms will remain
likely along and east of the Blue Ridge through 04Z, with rain
showers and isolated thunderstorms developing back to the west
tracking across the area again in the 02Z west to 08Z east range.
Periods of MVFR-IFR cigs in low clouds and fog along with MVFR-IFR
vsbys can be expected through much of the night. There is the
potential for IFR-LIFR fog development late tonight/early Tuesday
morning as well if any decoupling can occur before west winds pick
up behind the front, which will likely be after daybreak.
For the TAF valid hours after 14Z Tuesday, look for variable
clouds as an upper low begins to drift southward from the Great
Lakes region. Ceilings will range from IFR/MVFR in the morning to
high end MVFR or low end VFR by afternoon. Showers remain possible
in the far eastern Piedmont, including Danville, as a wave of
surface low pressure rides northeast along the slow moving frontal
boundary located over the coastal plain.
Winds light and variable overnight, becoming WNW-NW 5-8kts after
14Z Tue.
Medium confidence in cigs throughout the TAF valid period.
Low to medium confidence in vsbys through 14Z, then medium to high
confidence in vsbys through the remainder of the TAF valid period.
Medium confidence in wind direction/speed through the TAF valid
period.
Extended aviation discussion...
The front will be located across the coastal plain into Wednesday
awaiting additional upper support from an approaching upper low.
Conditions will becoming increasingly unsettled 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/RAB
SHORT TERM...DS
LONG TERM...DS
AVIATION...KK/PM/RAB
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
832 PM EDT MON SEP 26 2016
.UPDATE (Rest of Tonight through Tuesday)...
Another active day of convection across west-central and
southwest Florida is slowly coming to an end. Healthy storms
continue up over Levy county...but elsewhere the convection is
decaying or has moved offshore into the Gulf of Mexico.
Why was the convection stronger today than usual...with a few
severe storms and lots of reports of hail? Well...the answer to
that question can be seen on water vapor imagery and in the column
sampling from the 00Z KTBW RAOB from this evening. 00Z water vapor
and H4 RAP analysis shows troughing/closed low spinning over the
Florida Peninsula. Upper lows are cold core and often contain a
pocket of cooler than normal air in the mid/upper levels. This
upper low is no exception. The evening sounding showed 500MB temps
at or just below -10C...with zones of very healthy lapse rates
and decent CAPE through the hail growth zone. This -10C reading at
500mb is cold for this time of year...and helped support some very
strong updrafts and efficient hail production aloft.
Storms still around will slowly diminish into the later evening
hours...and after 11 PM or so...expect much of the area to see a
dry overnight period. These dry conditions will linger through the
morning hours Tuesday. The trough and some of the cold influence
aloft will still be around for Tuesday afternoon...although it
will be starting to shift eastward. The big difference from a
synoptic point of view between Monday and Tuesday...is that
Tuesday will see a much more defined low level 1000-700mb
southwesterly wind flow develop. This wind flow will help to more
rapidly propel the sea-breeze inland through the afternoon
hours...and help prevent convective outflow from heading back
west. Therefore...A few storms are possible near the beaches early
in the afternoon as the sea-breeze initially develops...but then
better chances will quickly shift inland past the I-75 corridor by
the later afternoon and evening hours. As I mentioned
above...these more easterly inland zones will also be under the
coolest temps aloft by later Tuesday. With this in mind...would
expect to see a good potential for strong updrafts...and resulting
small hail and intense lightning producing storms across portions
of Polk/Highlands/DeSoto/Hardee Counties. Obviously...weather does
not follow political boundaries...so anywhere in that vicinity
will potentially see stronger storms tomorrow. Before the storms
start to develop...temperatures will rise to within a degree or
two either side of 90 for afternoon highs.
Thanks for reading and have a great rest of your Monday evening...
&&
.AVIATION...
Convection is dissipating across west-central and SW Florida.
Small potential for a pop up storm near KFMY/KRSW through
02Z...but otherwise the storms are over. Cirrus canopy from
today`s storms will dissipate over next few hours...with VFR
conditions and light winds in place through the remainder of the
overnight. General VFR conditions expected for much of Tuesday as
well. Best potential for afternoon storms will be away from the
coast as a more defined southwesterly low level flow helps push
the sea-breeze well inland after mid-afternoon.
&&
.Prev Discussion... /issued 306 PM EDT MON SEP 26 2016/
SHORT TERM (Tonight - Tuesday)...
Currently in the upper levels, broad low pressure is spinning over
the northeastern Gulf of Mexico and is forecast to drift south
towards the Tampa Bay through tonight. This low is bringing cooler
temperatures in aloft, which could help support a few stronger
storms this afternoon/evening and again on Tuesday. At the surface,
a ridge of high pressure is currently sitting off the Mid-Atlantic
coast, while a cold front pushes into the southeastern CONUS.
Meanwhile, the Florida Peninsula remains under rather weak flow,
with slow steering flow keeping storm motion nearly stationary. With
precipitable water values holding around 1.5 inches or more, expect
scattered thunderstorms to develop again on Tuesday across the area.
Overall, Tuesday will shape up much like what was seen this weekend
and again today, with a few storms lingering over the waters through
the early morning hours, then isolated storms developing over the
Florida Peninsula during the early afternoon and expanding to
scattered coverage through the late afternoon and early evening
hours. Storms will then shift offshore and mostly dissipate through
the evening and overnight hours.
Temperatures will remain near to a couple degrees above normal, with
highs from the upper 80s to around 90, and lows tonight in the
70s.
MID/LONG TERM (Tuesday Night-Monday)...
Models in good agreement through the work week then start to
diverge over the weekend and into next week. Latest solutions
continue to keep large closed upper low spinning from north of the
the Great Lakes region Tuesday Night sinking southward into the
Ohio River valley Thursday. This low and associated trough moving
over the Gulf Coast region to push a surface cold front through
the Deep South mid- week and over the C FL peninsula Thursday
before stalling Friday. Expect warm and humid conditions with
diurnal scattered to numerous storms over the area ahead of the
front and then convective activity to be confined and remain south
of the front to end the week and into the weekend. Exact southern
extend of the front still in doubt, but expect much drier and not
as warm conditions over the N FL Peninsula to end the week into
the weekend. Upper low to lift into New England late in the
weekend and Monday but its still uncertain what, if any,
troughiness will remain in the region to steer any possible
tropical feature.
MARINE...
Weak high pressure will continue to hold north of the waters through
the next several days, with light and generally east winds turning
onshore each afternoon with the sea breeze. Scattered thunderstorms
will develop over the Florida Peninsula each afternoon and shift
west into the Gulf during the early evening, with a few storms
lingering overnight. Outside of thunderstorm activity, winds and
seas will remain rather light through the period.
FIRE WEATHER...
Relative humidity is forecast to remain above critical thresholds
through the week, with no fire weather concerns expected.
&&
.Preliminary Point Temps/PoPs...
TPA 75 88 76 87 / 20 30 10 40
FMY 74 89 75 88 / 50 40 20 40
GIF 72 90 73 88 / 20 50 10 50
SRQ 75 88 76 87 / 20 30 20 40
BKV 70 90 72 87 / 20 30 10 40
SPG 77 88 78 86 / 20 30 20 40
&&
.TBW Watches/Warnings/Advisories...
FL...Beach Hazards Statement through Thursday evening for
Coastal Manatee-Coastal Sarasota.
Gulf waters...None.
&&
$$
UPDATE/AVIATION...Mroczka
Previous Discussion...Fleming/Davis
Area Forecast Discussion
National Weather Service Albany NY
425 AM EDT TUE SEP 27 2016
.SYNOPSIS...
Showers will end this morning as the occluded front moves across
New England, as increasing afternoon sunshine will yield above
normal temperatures. Fair and mainly dry weather is expected
tonight into Wednesday. Unsettled weather returns Thursday into
the weekend as a slow moving low pressure system near the Ohio
Valley brings scattered showers to eastern New York and New
England.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 425 AM EDT...A band of showers continues this morning from
the Hudson River Valley eastward associated with the occluded
front. The latest HRRR has the showers quickly moving across the
forecast area between 08Z-10Z /4-6 AM/. Some residual light rain
showers or sprinkles may linger over portions of western New
England slightly later. Total rainfall amounts should average a
tenth to half an inch across the forecast area with the higher
totals south and east of Albany.
The subsidence in the wake of the front will allow for clearing
skies from west to east in the late morning into the afternoon.
The dry slot associated with strong cutoff low pressure system
over the western Great Lakes Region and Upper Midwest will move
over the region. In the southwest flow aloft...H850 temps will be
+8C to +10C over the region. Expect above normal temps for late
Sept with lower to mid 70s in the Mohawk...Hudson and CT River
Valleys...and mid and upper 60s over the hills and mtns.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
Tonight...A quiet night is expected with a weak sfc high moving in
over NY and New England in the southwest flow aloft. Light winds
and mostly clear/partly cloudy conditions will allow for
radiational cooling and some patchy fog formation in the major
river valleys. The low-level flow will become east or southeast
and this may focus some isolated showers across the higher terrain
of western New England during daybreak. Lows will be in the 40s to
lower 50s with a few upper 30s in the southern Adirondacks.
Wed-Wed night...The cut-off low centered over the Midwest will dig
further south and east. The long-wave trough with the embedded
cutoff will be mainly east of MS River Valley. Isolated showers or
drizzle is possible south and east of the Hudson River Valley
during the day. Partly to mostly cloudy conditions will persist
further west. It will be cooler than TUE with more clouds than sun
with the onshore flow. Highs will be in the 60s with some upper
50s over the southern Greens and northern Berkshires...portions of
the southern Adirondacks...and eastern Catskills. A few lower 70s
are possible in the mid-Hudson River Valley. Wed night...a short-
wave along the eastern flank of the cutoff lifts north-northeast.
Some of the moisture associated with this short-wave may get into
portions of the forecast area based on the GFS and some of the
GEFS...but the latest NAM and EC keep it mainly dry WEd night with
the short-wave and over running moisture from a frontal boundary
east of the stacked low staying south and west of the forecast
area. Slight and low chc pops were used overnight with temps in
the mids 40s to lower 50s.
Thu-Thu night...Cutoffs are always challenging to forecast in
terms of the timing of rain and the amounts /CSTAR research has
shown this over the years/. The guidance is converging on the
threat increasing for scattered showers during this time frame and
east to southeast h850-700 low-level flow increasing. A front
actually sets up over NY and PA with the cutoff still well to the
south and west of the region...and high pressure trying to build
in from southeast Quebec and Northern New England. The convergence
along this front and the onshore fetch of Atlantic moisture will
increase the chances for showers and damp conditions. Temps will
be a shade cooler during the day...and similar to the previous
nights mins in maritime air mass.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
A vertically stacked low pressure system will impact the forecast
through the period. Guidance has come into somewhat better agreement
however uncertainty definitely remains. Guidance indicates the low
is expected to be located over the Tennessee Valley/Ohio Valley by
Friday morning. It is then expected to begin to drift back northward
moving over the Great Lakes region over the weekend as it fills and
weakens. A northeastward movement across the Northeast is indicated
for Monday. Winds will be light with an onshore easterly flow bringing
in moisture off the Atlantic. Overall looking at an unsettled, mostly
cloudy forecast with chances for showers each day. as for temperatures,
near seasonable daytime highs with above normal nighttime readings
due to the cloud cover.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
Showers continue to make eastward progress across the region ahead
of an approaching occluded boundary. This occluded boundary will
move across the region this morning with MVFR conditions with IFR
conditions possible near and behind the boundary after the
showers end; have indicated this threat in a TEMPO group. Conditions
are expected to improve back to VFR by mid to late morning with
cloud cover decreasing for the afternoon with mostly clear skies
by late in the day/evening.
Light southerly winds with shift more to the southwest in the wake
of the boundary but should remain light. A more westerly flow is
expected at KPSF.
Outlook...
Wednesday Night: Moderate Operational Impact. Chance of SHRA.
Thursday: Moderate Operational Impact. Chance of SHRA.
Thursday Night: Moderate Operational Impact. Chance of SHRA.
Friday: Moderate Operational Impact. Chance of SHRA.
Friday Night: Moderate Operational Impact. Chance of SHRA.
Saturday: Moderate Operational Impact. Chance of SHRA.
&&
.FIRE WEATHER...
Showers will end this morning as the occluded
front moves across New England...as increasing afternoon sunshine
will yield above normal temperatures. Fair and mainly dry weather
is expected tonight into Wednesday. Unsettled weather returns
Thursday into the weekend as a slow moving low pressure system
near the Ohio Valley brings scattered showers to eastern New York
and New England.
The RH values will lower to 40 to 55 percent this afternoon...and
have an excellent recovering to 90 to 100 percent tonight. They
will lower only to 45 to 65 percent Wednesday afternoon.
The winds will shift to the southwest to west at 5 to 10 mph for
today...and become light to calm tonight. The winds will vary from
the northeast to southeast at 5 to 10 mph on Wednesday.
&&
.HYDROLOGY...
No widespread hydro issues are expected the next 5 days ending on
Saturday.
Total rainfall amounts of one tenth to a half of an inch are
expected from the occluded front this morning. A brief spell of
dry weather is expected this afternoon into most of Wednesday.
There is an isolated threat of showers east of the Hudson River
Valley on Wed.
Isolated to scattered showers may return Wednesday night into
Saturday with a cutoff cyclone. The amount of rainfall is
uncertain during the stretch...but totals of a quarter to three
quarters of an inch will be possible in some locations depending
on the track of the cutoff.
The U.S. Drought Monitor released on September 22nd shows drought
conditions have changed very little across the region. The next
issuance will be on September 29th. For details visit:
www.drought.gov
For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our
website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...Wasula
NEAR TERM...Wasula
SHORT TERM...Wasula
LONG TERM...IAA
AVIATION...IAA
FIRE WEATHER...BGM/Wasula
HYDROLOGY...BGM/Wasula
Area Forecast Discussion
National Weather Service BROWNSVILLE TX
409 AM CDT Tue Sep 27 2016
.SHORT TERM (Today through Wednesday):
Locally heavy rainfall will still be possible, mainly along the
immediate coastal areas, over the next 24 hours as a coastal
trough/stalled frontal boundary remains in the area along with
copious moisture. Precipitable water values will be around 2.2
inches over the eastern CWA as NE surface flow continues to feed
in Gulf moisture. Recent HRRR runs indicating localized rainfall
of 2+ inches per hour in spots around daybreak today. This seems a
bit overdone, but did add heavy rain wording to weather for the
coastal counties through the day. WPC also keeping the SE CWA in a
marginal risk for excessive rainfall today...with areal average
precipitation amounts of 1-2" possible. MOS guidance also
supporting this possibility around the Brownsville area.
On the other hand...upper-level pattern not really conducive to
heavy rain production, as upper-level lows apparent on water-vapor
satellite imagery over Lake Superior, Baja California, and SE CONUS
leave much of Texas in area of general ridging aloft. Instability
will also be largely limited with light northerly flow and cloudy
skies expected today. With all that said, basically going with WPC
QPF amounts but not confident enough to issue a Flash Flood Watch at
this time. Of course need to monitor the situation. PoP and QPF
totals fall off quickly further inland.
Daytime max temperatures on Tuesday will run 4-5 degrees below
normal with cloud cover and northerly flow in place.
Overnight Tuesday into Wednesday, an upper-level ridge amplifies
upstream of the area ahead of the old low over the SW CONUS. Column
moisture stays fairly high, though, especially along the coast, so
rain chances continue there overnight. Min temps range from the mid-
70s along the Gulf to perhaps the upper 60`s in Zapata county.
On Wednesday, column RH finally starts to decrease a bit as flow
aloft becomes more northerly. Some signal in the models that winds
will turn NE again during the day though...bringing increased rain
chances to (you guessed it) the SE part of the CWA including
Brownsville. Not especially confident in this yet, but something
for later shifts to keep an eye on.
.LONG TERM (Wednesday Night through Monday): The H5 ridge will be
more dominant through the period, deflecting weather systems away
from the region. The remnants of the cold front/coastal trough
will still be lurking near the lower valley and offshore by
Thursday morning, but reinforcing high pressure will be surging
southward across Texas during the day. Will hold on to isolated
shower forecast for the lower valley due to just enough remaining
moisture and surface instability. Drier air surging into Deep
South Texas will finally clear things out Friday and for the
weekend. Will keep high temperatures close to consensus, reaching
the low to mid 90s. Dewpoints will be considerably lower over the
weekend, so the heat will not be as stifling as the past few
weeks.
&&
.MARINE:
Now through Wednesday: Scattered showers and isolated
thunderstorms at times will be possible over the coastal waters
through the short-term. Heavy downpours are likely to occur in
some of the showers. Moderate NE winds today may approach SCEC
levels but should stay just below before falling to light-to-
moderate tonight and into Wednesday. Moderate seas of 2-4 ft. will
be the rule.
Wednesday night through Friday: Northeast flow will continue for
the marine zones through the rest of the week, with modest seas
continuing. A reinforcing arrival of high pressure will nudge
northeast flow back up to near 15 knots briefly on Thursday,
continuing to produce seas of 3 to 4 feet and a moderate chop on
the Laguna Madre.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 84 76 87 76 / 70 40 40 30
BROWNSVILLE 85 73 89 75 / 60 40 50 30
HARLINGEN 85 73 89 73 / 50 30 40 20
MCALLEN 85 73 90 76 / 30 10 40 10
RIO GRANDE CITY 83 71 89 72 / 20 10 20 20
SOUTH PADRE ISLAND 84 78 85 81 / 60 40 50 40
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
This product is also available on the web at:
HTTP://WEATHER.GOV/RGV
53/64
Area Forecast Discussion
National Weather Service Goodland KS
152 AM MDT TUE SEP 27 2016
.SHORT TERM...(Today through Thursday night)
Issued at 152 AM MDT Tue Sep 27 2016
Early morning WV imagery and RAP upper level analysis shows large
scale ridging across the Intermountain West extending northwards
across the Canadian Rockies. Two closed upper low are sandwiched
on either side of this upper level ridge: one over the Great
Lakes, and another over the Baja Peninsula. Our CWA remains
predominantly under the influence of the upper level ridge. At the
surface, high pressure remains in place over our CWA.
Today-Thursday night: Upper level ridge will continue to dominate
pattern across the Central High Plains, with a very stable/dry air
mass persisting. By Thursday night the ridge begins to move just
east enough for SW flow to develop, however there will be very
little impact on sensible weather during that forecast period.
Today will be the warmest of the next 3, with highs ranging from
the low to mid 80s. A backdoor cold front is still expected to
move across the region Wednesday and Wednesday night as a
shortwave trough rounds the western extent of the closed upper
low shifting southward over the Ohio River Valley. Falling
heights and weak CAA will result in temps gradually trending back
towards seasonal normals Thursday (mid to upper 70s).
.LONG TERM...(Friday through Monday)
Issued at 152 AM MDT Tue Sep 27 2016
Mainly dry conditions are anticipated through the first half
of the weekend before shower and thunderstorm chances increase
Sunday. Temperatures remain steady, with highs generally in the 70s
and lows in the mid 40s to low 50s.
Guidance has come into better agreement at the start of the
extended period with a closed low over the Ohio River Valley and
ridging over the Plains. The ridge breaks down on Friday and
Saturday as the next low pressure system pushes onto the west
coast. The upper low over the eastern CONUS lifts northward Sunday
and Monday and southwesterly flow strengthens aloft ahead of the
incoming trough, with a weak cold front advancing towards the
region.
Moisture gradually increases as a series of shortwaves work their
way through the southwesterly flow and across the High Plains.
These disturbances generate shower and thunderstorm chances
Friday night into the weekend. However, the majority of the
forecast area looks to stay dry through Sunday with the best
chance for precipitation looking to be Sunday evening into Monday
as the next system nears the region.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1140 PM MDT Mon Sep 26 2016
VFR conditions continue for the TAFs. Winds will be light and
primarily from the west to northwest. KMCK did have the visibility
drop to 4 miles prior to TAF issuance but has now improved. No
other sites are reporting lower visibility so may be dust from
nearby field moving across the runway.
&&
.GLD Watches/Warnings/Advisories...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JBH
AVIATION...JTL
Area Forecast Discussion
National Weather Service Saint Louis MO
324 AM CDT TUE SEP 27 2016
.SHORT TERM... (Through Late Tonight)
Issued at 315 AM CDT Tue Sep 27 2016
Still expect a sunny day as the area will continue to lie under
northwesterly flow aloft with little in the way of moisture through
a deep layer. Went with highs closer to the warmer NAM MOS
temperatures which supports the RAP forecast soundings that show
mixing up into the 850-800 layer by this afternoon. Both the GFS
and NAM are showing a weak upper trough moving through Missouri and
Illinois from the northwest which will bring an attendant surface
cold front into the CWA between 06-12Z. This trough will produce
some weak mid-level ascent, but have no moisture to work with, so
only expect partly cloudy skies with its passage and no rain. Lows
tonight should be close to the MOS lows which match up nicely.
Britt
.LONG TERM... (Wednesday through Monday)
Issued at 315 AM CDT Tue Sep 27 2016
Wednesday morning will see the strong cutoff low moving from near
Chicago southeast across Indiana possibly into western Ohio. The
cold front associated with the surface low should be through our
CWFA by 18Z Wednesday. Models are showing a tremendous amount of
mid-upper level vorticity dropping south over the area on the
western side of the low. Forecast soundings are showing steep low
level lapserates and RH plan views are showing RH values in excess
of 85% between 900-850mb during the late morning and afternoon
behind the front. This suggests there will probably be a decent
strato-cu field behind the front. While MOS PoPs are very low, and
there is no model QPF, I wouldn`t be surprised to see some light
rain showers or sprinkles develop as well...primarily along and east
of the Mississippi. With Strong cold air advection and strato-cu,
ensemble guidance temperatures are probably too warm...so am leaning
heavily toward the cool side of MOS. With the cool start to the
evening and likely clearing sky Wednesday night, lows look likely to
dip into the upper 40s and low 50s which will be the coolest
readings since May for most locations.
Remainder of the week should remain seasonably cool under the
influence of a sprawling Canadian high pressure system. The mid
and upper level cutoff is still forecast to meander over the Ohio
Valley and mid-Appalachians. This will keep the Mississippi Valley
in northwest flow aloft, and block up the pattern so not much will
change probably through at least Sunday. Temperatures should
moderate a bit from Wednesday and Thursday`s coolest readings, but
guidance temps stay a bit below normal through the period and this
looks reasonable given the pattern. Also...would not be at all
surprised to see a few showers or sprinkles east of the
Mississippi each afternoon with the cutoff lurking over the Ohio
Valley. Medium range models have the cutoff finally ejecting
northeast Sunday night and Monday, but am not sure there will be
much change in sensible weather other than a more east-southeast
direction to the surface flow as another trof begins developing
over the Great Plains.
Carney
&&
.AVIATION... (For the 06z TAFs through 06z Tuesday Night)
Issued at 1137 PM CDT Mon Sep 26 2016
Still looking at the potential for some river valley fog at KSUS
overnight however confidence is marginal. Otherwise VFR flight
conditions will prevail through the forecast period.
SPECIFICS FOR KSTL:
VFR flight conditions will prevail through the forecast period.
Glass
&&
.FIRE WEATHER...
Issued at 317 PM CDT Mon Sep 26 2016
Winds between 12 and 15 mph and minimum relative humidity between
25 and 30 percent will combine with dry fuels to produce an
elevated fire danger across parts of northeast Missouri and west
central Illinois again this afternoon. Higher relative humidities
and lower wind speeds further south should limit the fire danger
across the rest of the area.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Melbourne FL
347 AM EDT TUE SEP 27 2016
.DISCUSSION...
Today...Upper level trough near the FL west coast is forecast to move
eastward over east central FL and move into the Atlc waters this
evening and tonight. The mid level trough looks to be lingering
slightly west of the upper level trough and should provide increased
mid level lift into the late afternoon as it moves toward the area.
Surface low pressure is forecast to move NE off the Carolina coast with
a trailing trough across north FL. Deepest moisture with PWATs to 1.8
to 2.0 inches will remain across the Okeechobee county and the Treasure
coast where higher POPs up to 50 percent range will be advertised
across the far south. Further north GFS has lower pwats in the 1.5 to
1.7 inch range across nrn areas but with cooling mid level temps to -8
to -9 at H5 over portions of the area should see at least isolated to
low scattered coverage of late afternoon convection developing. An
afternoon sea breeze moving slowly inland across the coastal counties
will also provide a focus for some late day storms with activity moving
toward the east coast with mid level WSW flow at 10-15 knots. HRRR and
GFS hint that most robust convection should be across far srn sections
in the late afternoon into the evening, but some drier air at the mid
levels could allow for some isolated strong storms across nrn sections
late as well. Small hail, frequent lightning and gusty winds may occur
with the strongest storms. Highs in the upper 80s to around 90. An east
swell will contribute to a moderate risk of rip currents at the beaches.
Tonight...Isolated to scattered evening convection should focus across
eastern portions of ECFL before pushing off into the Atlantic through
late evening. Mid level trough at H5 will move across the central FL
peninsula overnight which will allow convection to focus ahead of it
across the Atlantic waters for the overnight hours. Lows will be mainly
in the lower 70s.
WED-THU...A weaker frontal boundary will exist across the southeast
U.S. into mid week. Farther north, a deep low pressure system over the
great lakes region digs southward into the Ohio Valley, pushing a
stronger reinforcing cold front into north Florida late Thursday.
A deeper W/SW flow ahead of this boundary and sufficient moisture will
exist over the region for scattered showers and storms to develop and
track E/NE across the central Florida peninsula and offshore into the
afternoon. Low level offshore flow looks like it will remain weak
enough on Wednesday for the sea breeze to form and stall near the east
coast, but sea breeze formation looks less likely for Thursday as
offshore winds strengthen. The presence of the sea breeze on Wednesday
(and Thursday if it can develop) will help enhance any storms near the
coast from any late day boundary collisions, with a few stronger storms
possible. Highs forecast to reach the upper 80s both days with morning
lows in the low-mid 70s.
FRI-MON...Models still not in the best agreement with how far south
front and drier air behind the boundary will make it into central
Florida late Thursday night into Friday. The latest GFS, while not as
far south with the front as 24 hours ago, is still farther southward
with it`s placement than the ECMWF, reaching near Orlando-Cape by
Friday morning. This would lead to lower than normal rain chances
across north central Florida Friday, and currently have rain chances
around 20 percent over this region, up to 30-40 percent farther south.
However due to model inconsistencies rain chance forecast remains more
uncertain for late week.
Still, any decrease in shower/storm coverage will be short lived as
front weakens and west Atlantic ridge axis lifts northward, allowing
for greater moisture increase in developing low level onshore flow into
the weekend. This will increase rain chances to near/slightly above
normal levels through the period.
Highs are expected to continue to reach the upper 80s over much of the
area each day with lows generally in the low to mid 70s.
However, could see min temps as low as the mid to upper 60s early
Friday/Saturday mornings northwest of I-4 if front can make it far
enough south across the region into late week.
&&
.AVIATION...
Scattered TSRA will dvlp from KMLB-KSUA into late afternoon-early
evening and then move into the Atlc by late evening. A slightly drier
airmass north of KISM-KTIX line should portend lower convective
coverage for areas around nrn terminals this afternoon with Chcs from
20-30 pct. Overall VFR conditions are expected outside of convective
activity.
&&
.MARINE...
Today and Tonight...Light offshore flow this morning will become
S/SE by late afternoon up to 10 knots. Seas 2 ft near shore to 3 ft
offshore. South winds this evening to 10 knots will veer to the SW-W
overnight. Slight increase in seas heights expected from 2-3 ft
nearshore to 3-4 offshore for the overnight hours. Highest convective
coverage is expected in the late afternoon and evening mainly south of
Cocoa Beach.
WED-SAT...Frontal boundary across the Southeast U.S. is forecast to
move into north Florida and potentially as far south as the Cape into
late week. W/SW winds up to 10-15 knots expected over the waters
Wednesday/Thursday and then flow weakens into Friday before becoming
onshore into the weekend as front lifts back northward and fades. Seas
will range from 2-4 feet through the period.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 88 72 88 73 / 30 20 50 20
MCO 90 73 88 73 / 30 20 50 20
MLB 88 72 88 73 / 40 30 50 20
VRB 89 71 88 72 / 50 30 50 20
LEE 89 73 87 73 / 20 10 40 20
SFB 90 73 89 73 / 30 20 50 20
ORL 91 74 89 73 / 30 20 50 20
FPR 89 71 88 72 / 50 30 50 20
&&
.MLB Watches/Warnings/Advisories...
FL...None.
AM...None.
&&
$$
SHORT TERM/AVIATION...Volkmer
LONG TERM....Weitlich
Area Forecast Discussion
National Weather Service Spokane WA
230 AM PDT Tue Sep 27 2016
.SYNOPSIS...
A mild and mostly dry weather pattern is expected through
Wednesday. Temperatures will be above average, with several days
of highs in the mid 70s to mid 80s. Cold front passage on Tuesday
will produce breezy winds down the Okanogan Valley. A pattern
change is expected to arrive late in the week with chances for
showers beginning Thursday and continuing into the weekend. By
Saturday and Sunday, afternoon temperatures will likely be in the
60s...possibly cooling further into the 50s next Monday.
&&
.DISCUSSION...
Today and Wednesday: Satellite imagery shows a cold front moving
across central BC and down across the northern portion of
Vancouver Island. The water vapor channel shows a noticeable dry
slot along the back edge of the front extending out from 130W to
150W in the Gulf of Alaska. The cold front will be fairly slow
moving and become hung up over the region late this afternoon into
this evening. The only precip is expected right up along the
Cascade crest, and will otherwise be too dry at lower levels for
any precip. The main impact with this weather feature will be for
breezy winds down the Okanogan Valley. I decided to favor the
higher resolution model guidance for the winds as they should more
accurately resolve the complex topography across this area. The
ARW, NMM and HRRR models show winds becoming quite breezy through
the Okanogan Valley with winds picking up after 9:00 AM this
morning and peaking in the early afternoon. Expect sustained winds
of 15 to 25 mph with gusts to around 35 mph possible. The
northerly winds will also draw down much drier air with dew points
crashing from the lower 40s to the lower 30s through the
afternoon hours. The combination of breezy winds and low relative
humidity will heighten fire weather concerns for any new fire
starts.
Winds will weaken overnight on Tuesday into Wednesday. The cold
front will generally become hung up over the region with a thin
band of mid to high level clouds stretching across the basin into
the Northeast Mtns and Northern Panhandle. Temperatures will cool
down a bit compared to yesterday but remain above normal for
early fall with highs ranging from the mid 70s to mid 80s. /SVH
Wednesday night through Saturday...We are looking for a quite cool
and unsettled weekend coming. This is courtesy of a deep low
pressure system that will move out of the gulf of Alaska on
Wednesday and move southeast towards the WA/OR coast late in the
day Thursday. The low will then linger off the coast and be the
main weather producer in some form or another well into into next
week. The upper level flow will become southwest Wednesday night
and Thursday and gradually shift to the south as the low
approaches the coast Friday and Saturday. This flow pattern will
tap into some pretty deep Pacific moisture as well. PWATs will
increase to between 0.75 to 0.85 during this period. This is about
160-170 percent of average. The increase in moisture will increase
mid level instability. Lift will mainly be provided by terrain for
an increasing chances of showers Thursday through the weekend. In
addition, numerous short wave disturbances are expected to eject
off the main low and these will be the focusing point for more
intense showers. All of the components are coming together for at
least a chance for thunderstorms for the Idaho Panhandle and
mainly near the border with Montana Friday afternoon. Rainfall
amounts through Saturday afternoon will generally be light with
most of the mountain location seeing between a trace and a tenth
of an inch and little to none for the lower elevations. Snow
levels start out between 9000-11,000 feet on Thursday and are
expected to drop down to between 5000-6000 feet by Saturday. Only
a dusting of snow is expected for the Cascades Saturday morning.
Temperatures on Thursday will be in the 70s and still 5-10 degrees
on the warm side of normal. Temperatures will cool off 4-6 degrees
on Friday and 8-10 degrees on Saturday. High temperatures on
Saturday will have a tough time making it int the lower to mid
60s. Tobin
Sunday to Tuesday: Models begin to diverge on the exact placement
of the upper low as it crosses the region, but generally agree
with it passing on or about Monday. Multiple shortwaves will
rotate around the trough on Sunday and Monday with plenty of deep
moisture to work with, keeping rain likely. Sunday looks wet
mostly for areas around the basin, but the strongest shortwave and
most widespread rain come late Sunday and on Monday. The trough`s
continued influence will keep temps down in the upper 50s and low
60s. A tightening pressure gradient with the passage of a surface
low to the northeast on Monday will also bring gusty winds to the
Columbia Basin. /bwilliams
&&
.AVIATION...
06Z TAFS: A weak cold front will track into Central and Northeast
Washington into the Idaho Panhandle on Tuesday. This front will
bring a band of mid and high clouds as well as an increase in
winds down the Okanogan Valley. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 78 52 79 55 77 50 / 0 0 0 10 10 30
Coeur d`Alene 78 52 79 54 77 50 / 0 0 0 10 10 30
Pullman 79 52 80 54 76 49 / 0 0 0 10 10 40
Lewiston 85 57 85 59 81 54 / 0 0 0 10 10 10
Colville 79 44 78 48 79 45 / 0 0 0 10 10 10
Sandpoint 75 46 75 49 75 47 / 0 0 10 10 10 20
Kellogg 76 50 79 52 76 48 / 0 0 0 10 10 40
Moses Lake 81 49 80 49 79 45 / 0 0 0 0 0 10
Wenatchee 78 53 78 51 77 49 / 0 0 0 0 0 10
Omak 79 47 78 49 79 47 / 0 0 0 0 0 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion
National Weather Service Tucson AZ
245 AM MST TUE SEP 27 2016
.SYNOPSIS...A low pressure system over central Baja California will
move north into southern California tonight. This system will bring
scattered showers and thunderstorms mainly this afternoon and
evening. Moisture will remain sufficient for a chance of showers and
thunderstorms especially east of Tucson Wednesday and Thursday. Dry
conditions will return area wide late this weekend.
&&
.DISCUSSION...Water vapor imagery this morning showed upper level
cut-off low over central Baja/Gulf of California. Radar showed
scattered showers/thunderstorms across northern Baja moving north
northwest while across SE Arizona there were spotty light showers.
As the cut-off low lifts to the north today, showers will be
increasing in coverage as the morning progresses, especially south
of Tucson. Latest HRRR runs along with 12z UofA WRF runs of NAM/GFS
all spread showers/storms near the intnl border north and northeast
across Pima/Santa Cruz. Some of these storms will briefly be strong
with outflow winds potentially bringing areas of blowing dust
between Tucson and Phoenix. Localized mod/hvy rainers with PW values
slightly over 1". However flash flooding threat low due to speed the
storms will be moving. With that said, made some significant upward
adjustments in PoPs and QPF for central/eastern Pima and Santa Cruz
counties.
Upper low continues north into southern California overnight with
gradual decrease in areal coverage of showers across the area.
Some moisture from TS Roslyn may spread toward the area on Wednesday
and Thursday keeping a chance of showers and storms across the area
as Monsoon 2016 comes to a close.
Drier SW flow aloft will push moisture to the east on Friday but
enough will be around to support a slight chance east of Tucson.
Dry westerly flow aloft this weekend into early next week as upper
level trofs pass by to the north.
Although warmer today versus Monday, highs will remain below normal
through Thursday then hang around normal values Friday into early
next week.
&&
.AVIATION...Valid through 28/12Z.
Generally BKN-OVC clouds at 6-10k ft AGL thru the period, however
brief MVFR conditions and higher terrain obscurations may occur on
occasion. ELY/SELY sfc winds at 10-15 kts with a few gusts to near
20 kts are expected thru 28/03z...and aft 28/03z decreasing sfc wnd
to 8-12 kts thru the remainder of the forecast period. Aviation
discussion not updated for TAF amendments.
&&
.FIRE WEATHER...There will be a slight chance to chance of showers
and thunderstorms through Friday. East to southeast surface winds at
10-15 mph with some higher gusts will persist through Thursday.
Expect normal diurnal wind patterns to resume late this week into
the upcoming weekend. Dry and warmer weather is also expected over
this upcoming weekend.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE
&&
$$
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion
National Weather Service Las Vegas NV
250 AM PDT TUE SEP 27 2016
.SYNOPSIS...An area of low pressure will slowly move up the Gulf of
California and into southeast California by tomorrow afternoon
before lifting into the Great Basin on Thursday. Scattered showers
and thunderstorms will be possible across the area through Thursday
before becoming more localized later in the week. Temperatures will
generally be within few degrees of normal into Saturday.
&&
.SHORT TERM...through Thursday Night.
One area of low pressure is currently located at the northern
portion of the Gulf of California. With that location, easterly flow
is dominant across Mohave and San Bernardino Counties and mid to
high level cloud cover has been enhancing overnight along with a few
light radar returns of which are not yet likely producing any precip
at the surface. During the day expect continued moistening with the
best opportunity of showers and thunderstorms over southeast San
Bernardino, southern Clark and Mohave Counties. The NCAR ensembles
and local hi res models all show a similar depiction with the
operational HRRR being much drier. As the low lifts into southeast
California on Wednesday, a more substantial push of moisture will
advance northward through Mohave County and into southern Nevada
during the day. Most models are indicating modest instability with a
few hundred J/kg and lifted indices of 0 to minus 2. The NAM was
indicating the most instability with values nearly doubled. Expect
Wednesday to be the wettest day across the region with isolated to
scattered thunderstorms across the forecast area and more numerous
showers and storms in Mohave County and the higher terrain of
southern Nevada where brief heavier downpours are possible. The
upper low lifts northward and into central Nevada during the day on
Thursday. Meanwhile, moisture associated with Tropical Storm Roslyn
will work its way into Arizona during the day on Thursday. This will
keep the chance of showers and thunderstorms over Mohave County and
the potential for a more significant rain producer. However, models
are currently keeping the bulk of the moisture further to the east
and in central and eastern Arizona.
.LONG TERM...Friday through Monday Night.
The weather pattern looks to remain active in the extended period
with the possibility of additional troughing influencing the region.
On Friday...southwesterly flow aloft along with some lingering
moisture and instability may promote some isolated to scattered
mountain shower activity across Clark...Lincoln..and Mohave counties
but increasing subsidence and drying aloft should keep things
closely tied to the terrain through the day. Model agreement
decreases over the weekend with ECMWF suggesting a fairly
significant trough digging into the western US while the GFS is
considerably weaker and keeps most of the energy further to our
north. Both solutions would favor breezy conditions and a cooling
trend of some magnitude late in the weekend into early next week.
However...the ECMWF would support a stronger wind episode over the
weekend along with greater cooling associated with a more marked
cold frontal passage. For now I`ve maintained a dry forecast with
modest cooling Sunday into Monday with temperatures falling a few
degrees below normal. I`ve also bumped up wind speeds across the
region as nod towards the ECMWF. If the EC solution maintains some
consistency temperatures may be tweaked downward further as the
event approaches.
&&
.FIRE WEATHER... A low pressure system moving in from the south
today will increase moisture for most of the area by Wednesday.
Shower and thunderstorm chances will initially enter northwest
Arizona and southeast California today...overspread the area
Wednesday...then decrease as the area dries out from west to east
through the end of the week. Some easterly breezes remain possible
across the far western Mojave Desert. There is the potential for a
stronger wind event over the weekend and will be monitoring for
potential fire weather concerns.
&&
.AVIATION...For McCarran...Generally light and variable winds
for the rest of the night. Today will bring light northeast winds,
increasing clouds, with dry weather for the Las Vegas Valley but a
chance of a showers and thunderstorms along the Peach Springs
corridor. Shower and thunderstorm chances increase on Wednesday.
For the rest of southern Nevada...northwest Arizona...and southeast
California...Generally light winds expected area-wide. Some
exceptions may be across the western Mojave Desert where east
breezes may prevail. Increasing clouds and shower/thunderstorm
chances will enter northwest Arizona and southeast California today.
Shower and thunderstorm chances increase across the area on
Wednesday.
&&
.SPOTTER INFORMATION STATEMENT...Shower and thunderstorm chances
will increase in Mohave County today, overspread most of the area
Wednesday and begin decreasing the rest of the week. Spotters are
encouraged to report rainfall amounts and any other significant
local weather.
&&
$$
Short Term/Aviation/Fire...Czyzyk
Long Term..................Outler
For more forecast information...see us on our webpage:
http://weather.gov/lasvegas or follow us on Facebook and Twitter
Area Forecast Discussion
National Weather Service BROWNSVILLE TX
641 AM CDT Tue Sep 27 2016
.DISCUSSION...Updated for latest aviation discussion below.
&&
.AVIATION...Complicated aviation forecast this morning with
showers currently moving in NE to SW from the Gulf and expected
to continue through the day, especially near the coast, due to a
surface trough/weak frontal boundary in the area. Expecting main
impacts at BRO and possibly HRL...with lesser rain chances inland
at MFE. Downpours are possible, mainly at BRO. Thunder cannot be
completely ruled out this afternoon, but instability is quite
limited, so will not mention in TAF`s. CIG`s have also been
falling to IFR (007-010) in showers this morning. Will carry SHRA
in TEMPO groups at BRO/HRL through 00Z then PROB30 until 06Z. Just
TEMPO at MFE this afternoon for now.
&&
.PREV DISCUSSION... /issued 409 AM CDT Tue Sep 27 2016/
SHORT TERM (Today through Wednesday):
Locally heavy rainfall will still be possible, mainly along the
immediate coastal areas, over the next 24 hours as a coastal
trough/stalled frontal boundary remains in the area along with
copious moisture. Precipitable water values will be around 2.2
inches over the eastern CWA as NE surface flow continues to feed
in Gulf moisture. Recent HRRR runs indicating localized rainfall
of 2+ inches per hour in spots around daybreak today. This seems a
bit overdone, but did add heavy rain wording to weather for the
coastal counties through the day. WPC also keeping the SE CWA in a
marginal risk for excessive rainfall today...with areal average
precipitation amounts of 1-2" possible. MOS guidance also
supporting this possibility around the Brownsville area.
On the other hand...upper-level pattern not really conducive to
heavy rain production, as upper-level lows apparent on water-vapor
satellite imagery over Lake Superior, Baja California, and SE CONUS
leave much of Texas in area of general ridging aloft. Instability
will also be largely limited with light northerly flow and cloudy
skies expected today. With all that said, basically going with WPC
QPF amounts but not confident enough to issue a Flash Flood Watch at
this time. Of course need to monitor the situation. PoP and QPF
totals fall off quickly further inland.
Daytime max temperatures on Tuesday will run 4-5 degrees below
normal with cloud cover and northerly flow in place.
Overnight Tuesday into Wednesday, an upper-level ridge amplifies
upstream of the area ahead of the old low over the SW CONUS. Column
moisture stays fairly high, though, especially along the coast, so
rain chances continue there overnight. Min temps range from the mid-
70s along the Gulf to perhaps the upper 60`s in Zapata county.
On Wednesday, column RH finally starts to decrease a bit as flow
aloft becomes more northerly. Some signal in the models that winds
will turn NE again during the day though...bringing increased rain
chances to (you guessed it) the SE part of the CWA including
Brownsville. Not especially confident in this yet, but something
for later shifts to keep an eye on.
LONG TERM (Wednesday Night through Monday): The H5 ridge will be
more dominant through the period, deflecting weather systems away
from the region. The remnants of the cold front/coastal trough
will still be lurking near the lower valley and offshore by
Thursday morning, but reinforcing high pressure will be surging
southward across Texas during the day. Will hold on to isolated
shower forecast for the lower valley due to just enough remaining
moisture and surface instability. Drier air surging into Deep
South Texas will finally clear things out Friday and for the
weekend. Will keep high temperatures close to consensus, reaching
the low to mid 90s. Dewpoints will be considerably lower over the
weekend, so the heat will not be as stifling as the past few
weeks.
MARINE:
Now through Wednesday: Scattered showers and isolated
thunderstorms at times will be possible over the coastal waters
through the short-term. Heavy downpours are likely to occur in
some of the showers. Moderate NE winds today may approach SCEC
levels but should stay just below before falling to light-to-
moderate tonight and into Wednesday. Moderate seas of 2-4 ft. will
be the rule.
Wednesday night through Friday: Northeast flow will continue for
the marine zones through the rest of the week, with modest seas
continuing. A reinforcing arrival of high pressure will nudge
northeast flow back up to near 15 knots briefly on Thursday,
continuing to produce seas of 3 to 4 feet and a moderate chop on
the Laguna Madre.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
This product is also available on the web at:
HTTP://WEATHER.GOV/RGV
53/64
Area Forecast Discussion
National Weather Service Columbia SC
1029 AM EDT TUE SEP 27 2016
.SYNOPSIS...
A cold front will slowly push into the area later today into
Wednesday and cross the area Wednesday night. Cooler and drier
more seasonable temperatures expected late in the week and over
the weekend with little rain chances.
&&
.NEAR TERM /THROUGH TONIGHT/...
Latest analysis depicts the cold front extending from eastern
West Virginia southwestward along the spine of the Appalachians
into northern Georgia. Weak surface low remains off the Southeast
coast. Precipitable water values remain above normal for this time
of year around the 90th percentile with abundant low level
moisture present with dewpoints in the upper 60s to lower 70s.
Regional radar currently showing mainly dry across much of the
state late this morning.
Latest SPC HRRR indicating that convection will develop over the
Upstate by late afternoon and move eastward into the evening
hours. There is not much upper support to enhance convection but
should be enough instability to support unorganized scattered
convection late afternoon and evening mainly across the northern
and western parts of the forecast area so will continue to carry
highest pops there with lower pops elsewhere. Weak surface low
offshore will also lift northward through tonight and limit
convergence along the seabreeze. Cannot rule out an isolated
strong to severe storm but the overall severe threat appears low.
The high moisture content and possible training of convection may
lead to a limited isolated flood threat especially in the northern
Midlands where recent rain has fallen.
Temperatures will remain well above normal with afternoon highs
once again expected in the mid to upper 80s with strong
insolation. Debris clouds and abundant boundary layer moisture
will limit overnight lows tonight as temperatures are expected to
be in the upper 60s to lower 70s.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
The closed upper low over the Great Lakes region will dive
southeastward into the Ohio Valley Wednesday and Wednesday night
resulting in 500mb height falls across the forecast area and
increasing lapse rates as cooler air aloft overspreads the region.
The cold front that has been hung up in the mountains will provide
a focus for convection and with increasing winds aloft and a
moderately unstable atmosphere expected Wednesday, the threat of
organized convection is increasing. SPC has outlooked the area in
a marginal risk for severe storms with the main threat being
damaging winds. The drier air that had been forecast to move into
the area over the past couple of days looks to be a bit delayed
more into Wednesday evening now further supporting convection
during peak heating Wednesday. Have increased the pops across the
area although keeping them below likely due to some uncertainty in
amount of instability and resulting coverage of convection.
Temperatures should again remain warm with highs in the mid to
upper 80s as the region will be in the warm sector southeast of
the front.
The front is expected to cross the area sometime Wednesday night
and drier air will move into the region from the west ending
precipitation as cooler air builds in. Overnight lows will range
from the upper 50s west to mid 60s east.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Little change made during this period. Closed upper low will
meander around western NC and eastern TN on Thursday before
lifting back northward on Friday. Despite the proximity of the
upper low and associated cold temperatures aloft, moisture will be
quite limited with precipitable water values below an inch and
some downsloping low level flow which should preclude any diurnal
convection. Expect cooler temperatures closer to normal values
with diurnal cumulus each day Thu/Fri.
Generally fair weather expected over the weekend into early next
week with the upper low lifting away from the region replaced with
nearly zonal upper level flow and weak high pressure at the
surface. One feature that will need to be monitored though will be
the tropical wave moving towards the Lesser Antilles which could
be approaching Cuba or the Bahamas by the middle of next week.
Temperatures will be near normal with highs around 80 to the lower
80s and lows in the 50s.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
LIFR conditions at AGS and IFR at OGB late this morning, otherwise
VFR elsewhere. Abundant low-level moisture and light winds are
helping below-VFR conditions to linger. After any morning
restrictions, VFR expected today outside of scattered
late afternoon/evening showers and a few thunderstorms, which are
expected to develop along a slow moving prefrontal trough, and
remain mainly north of the terminals.
EXTENDED AVIATION OUTLOOK...Some potential for fog/stratus late
Tuesday night/early Wednesday morning. Chance of showers and
possible thunderstorms, and associated restrictions, Wednesday
afternoon. No impacts to aviation expected Thursday through
Saturday.
&&
.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 Goodland KS
504 AM MDT TUE SEP 27 2016
.SHORT TERM...(Today through Thursday night)
Issued at 152 AM MDT Tue Sep 27 2016
Early morning WV imagery and RAP upper level analysis shows large
scale ridging across the Intermountain West extending northwards
across the Canadian Rockies. Two closed upper low are sandwiched
on either side of this upper level ridge: one over the Great
Lakes, and another over the Baja Peninsula. Our CWA remains
predominantly under the influence of the upper level ridge. At the
surface, high pressure remains in place over our CWA.
Today-Thursday night: Upper level ridge will continue to dominate
pattern across the Central High Plains, with a very stable/dry air
mass persisting. By Thursday night the ridge begins to move just
east enough for SW flow to develop, however there will be very
little impact on sensible weather during that forecast period.
Today will be the warmest of the next 3, with highs ranging from
the low to mid 80s. A backdoor cold front is still expected to
move across the region Wednesday and Wednesday night as a
shortwave trough rounds the western extent of the closed upper
low shifting southward over the Ohio River Valley. Falling
heights and weak CAA will result in temps gradually trending back
towards seasonal normals Thursday (mid to upper 70s).
.LONG TERM...(Friday through Monday)
Issued at 152 AM MDT Tue Sep 27 2016
Mainly dry conditions are anticipated through the first half
of the weekend before shower and thunderstorm chances increase
Sunday. Temperatures remain steady, with highs generally in the 70s
and lows in the mid 40s to low 50s.
Guidance has come into better agreement at the start of the
extended period with a closed low over the Ohio River Valley and
ridging over the Plains. The ridge breaks down on Friday and
Saturday as the next low pressure system pushes onto the west
coast. The upper low over the eastern CONUS lifts northward Sunday
and Monday and southwesterly flow strengthens aloft ahead of the
incoming trough, with a weak cold front advancing towards the
region.
Moisture gradually increases as a series of shortwaves work their
way through the southwesterly flow and across the High Plains.
These disturbances generate shower and thunderstorm chances
Friday night into the weekend. However, the majority of the
forecast area looks to stay dry through Sunday with the best
chance for precipitation looking to be Sunday evening into Monday
as the next system nears the region.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 504 AM MDT Tue Sep 27 2016
VFR conditions will continue through the TAF period at both KGLD
and KMCK. High pressure remains in place over both terminal,
resulting in light westerly winds (less than 10kt) through the TAF
period.
&&
.GLD Watches/Warnings/Advisories...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JBH
AVIATION...DR
Area Forecast Discussion
National Weather Service Gray ME
1022 AM EDT Tue Sep 27 2016
.SYNOPSIS...
A cold front will move well offshore this afternoon taking any
lingering showers with it. Conditions should dry out behind the
front with temperatures a few degrees warmer than Monday. Low
pressure developing along the offshore front will create a
northeasterly wind over Maine and New Hampshire Tuesday night,
bringing clouds back into the area. Several waves of low pressure
will track northeast along the front through the western Atlantic,
with an occasional chance of showers especially near the coast
throughout the week. The best chance of rain will be this weekend
when the large upper level low pressure system over the Great
Lakes lifts to the north, spreading rain into New England.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1022 AM...for this ESTF update I slowed the clearing and made
adjustments to near term grids to reflect satellite trends as well
as the 14z mesonet.
Prev Disc...
615 AM Update...Rain shield is moving through the area quickly and
should be offshore by 9 am if not sooner. Some models including
the HRRR have been too slow with this system. Have adjusted PoPs
as well as temperatures and dew points. So far, storm total
precipitation where it has rained has ranged from one tenth of an
inch to around a half inch in very localized spots.
Previous discussion...
Variable cloudiness across the region with warm overnight
temperatures in the 50s areawide and even 60 degrees this hour in
Nashua. Rain showers are just moving into NH and will eventually
reach Maine in the next 2-3 hours before exiting the coast by mid
morning. Most areas will see less than two-tenths of an inch out
of this particular system. Temperatures will rebound into the 60s
and 70s as skies clear from west to east.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
High pressure builds in quickly behind the front bringing cooler
and drier air into northern New England. Wednesday`s highs will be
cooler as a result around the upper 50s to the mid 60s. We will
still have a fair amount of cloud cover with the upper low
remaining nearby. Even as high pressure wedges against the higher
terrain, showers will continue to be possible along the coast with
a mid Atlantic low moving northeast along the coast. Will likely
see drizzle as well.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
A very large upper low that will be centered over the Ohio valley
throughout the latter part of the week will drift slowly
northeast over the weekend. This will produce a moist unstable air
mass well to its east. Unsettled weather with several periods of
rain or showers can be expected late in the week and into the
weekend. This will be accompanied by a damp onshore flow as a
broad persistent northeast maritime flow develops. With this
northeast flow cool temperatures are expected and not much of a
variation in diurnal temps expected. Models differ some on
features and timing of some of the periods of precipitation so
staying with a blend of models appeared best. Although a prolonged
period of unsettled weather is expected, qpf amounts from the slow
moving system will likely remain light overall as most models
generally keep the heavier areas of rainfall south and east of
the region.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
Short Term...Conditions have deteriorated this morning in showers
which will end by mid morning. We will see MVFR conditions with
IFR possible in heavy rain showers. Lower ceilings are more likely
along the coast. Tonight into Wednesday morning drizzle and
stratus will be possible. This could bring IFR conditions after
00Z Wednesday, with the western New Hampshire terminals HIE and
LEB least likely to be impacted.
Long Term...MVFR conditions move in Wednesday night through the
remainder of the period with some IFR conditions likely in any
fog/stratus that settles over the region at times due to the
persistent onshore maritime flow.
&&
.MARINE...
Short Term...A front crosses the region this morning. Winds will
be variable before becoming easterly tonight. Winds and seas will
flirt with SCA criteria beginning late tonight. Will let the day
shift take a look at the possibility of issuing a SCA.
Long Term...Winds and seas will remain at SCA levels through the
outlook period over the outer waters and possibly in the bays due
to a persistent northeast flow.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
ES
Area Forecast Discussion
National Weather Service Wilmington NC
950 AM EDT Tue Sep 27 2016
.SYNOPSIS...
A weak wave of low pressure moving just offshore will bring
scattered showers and a few thunderstorms today, mainly along the
coast. A cold front approaching from the west will stall through mid-
week before moving across the area on Thursday, maintaining warm and
unsettled conditions. Cool and dry high pressure will build into the
area by the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 940 AM Tuesday...A weak area of low pressure off the GA/SC
coast this morning is expected to move northeast along a coastal
trough during the day. The precipitable water will be above 1.8
inches along the coast, while the bulk of the tropical moisture will
remain offshore. The HRRR is not that robust regarding rainfall
chances and abundant cloud cover will likely hamper significant
destabilization. Thus lowered the POPs, but still expect to see
scattered showers and a few thunderstorms develop around the
forecast area through the evening. Otherwise, the cold front across
far western NC will only slowly move east through tonight. Currently
favor the cooler MAV numbers, especially across the eastern portion
of the forecast area where clouds will inhibit heating the most.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 400 AM Tuesday...Models are in an o.k. agreement in the
closed upper low becoming a cutoff upper low during this period,
as it breaks off from the main belt of the westerlies aloft. The
cutoff low will drop southward, reaching the Central Appalachians
by Friday daybreak. The extremely slow moving cold front from the
near term period, will only reach the Carolina coasts toward late
Thursday night. Forcing ahead of the cold front will alone keep
POPs active Wednesday into Thursday. However, and additionally,
dynamics associated with vorts or s/w trofs rotating around the
upper cutoff low, like spokes on a bicycle, may combine with the
sfc frontal dynamics. And, if this occurs during the max heating
of the day, then there will be a possibility that a few strong to
severe thunderstorms may occur especially on Wednesday and to a
lesser degree during Thursday. The FA does not get directly
underneath the cold pool aloft, ie. exhibiting steep lapse rates,
associated with the cutoff low. But nevertheless, temps aloft are
progged to lower just not to the extreme under the cutoff low
itself. Will highlight in the HWO the isolated threat for strong
to sever convection. On a side note, SPC does have the ILM CWA
within a marginal area on Wed. POPs will generally be hiest in the
aftn thru early evening each day. And will carry a low POP during
the overnights and early morning hours. Daily MAX/MIN temperatures
will run 1 to 2 categories hier than the climo normals thruout
this period.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 300 AM Tuesday...The extended remains a rather lower than
average confidence forecast due to discrepancies in the guidance
handling an anomalous cut-off low across the OH VLY. The ECM
continues to be a slow outlier, but once again the GFS/CMC, which
are in very good agreement today, have slowed from previous
solutions. This continues to lend some support to the ECM, and a
slower progression of the mid-level and surface features is likely,
just not quite to the extent the ECM continues to advertise. While
this upper low spins and ejects only very slowly NE through the
wknd, the surface cold front beneath it will drift east, crossing
the local area late Thursday, before being replaced by Canadian high
pressure. This suggests that cooler and drier conditions will be in
place for the majority of the extended, with temps at or slightly
below seasonable norms, and a nice early fall weekend is possible.
Must continue to note however that if the ECM ends up correct, this
front may not cross until Saturday, leaving much warmer and
unsettled conditions in place through the first half of the wknd.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
As of 12Z...Low pressure off the South Carolina coast combined with
a weak frontal boundary to our west will keep convection in the
picture through the afternoon hours. Time height indicates quite a
bit of mid cloud around today, so we will only get moderately
unstable at best. Light northeast winds this morning will become
easterly and onshore this afternoon. Light winds tonight with some
light fog possible after midnight.
EXTENDED OUTLOOK...Scattered SHRA/TSRA Tuesday through Thursday.
Cold frontal passage Thursday. VFR expected Friday/Saturday.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 940 AM Tuesday...Weak trough along the coastal waters will
result in variable winds across the SC waters and maintain easterly
flow across the Cape Fear waters. As low pressure off the GA/SC
coast moves northeast during the day expect easterly winds across
all waters. The pressure gradient is fairly weak and wind speeds
will remain around 10 knots through tonight. Scattered showers and
a few thunderstorms are possible through tonight as well.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 400 AM Tuesday...The area waters will be under the influence
of an expansive cutoff low that drops southward to the Central
Appalachians by the end of this period. A sfc cold front out ahead
of this cutoff low, will continue at a snail`s pace to the east,
finally reaching the coastal waters during late Thursday Night.
SSW to SW flow will dominate the local waters Wednesday into Thu,
then veer to the W and NW depending on the extent the cold front
pushes to or partially across the local waters. The sfc pg will
slowly tighten-some with time due to the approaching cutoff low.
Initially, wind speeds at 5 to 10 kt, then increasing to 10 to 15
kt or around 15 kt, Thu into Thu night prior to the cold front
reaching or partially moving across the local waters. Significant
seas will hoover, no relation to the vacuum, right around 3 ft.
Some fluctuations of 1 foot either higher or lower than the 3 ft
will occur. For the most part, wind waves at 4 to 6 second periods
will dominate. No underlying 1 to 1.5 foot easterly ground swell
at 8 to 9 second periods will be present. Convection may become
strong to possibly severe during Wednesday and again on Thu.
LONG TERM/FRIDAY THROUGH SATURDAY/...
As of 300 AM Tuesday...A cold front will slowly move across the
waters on Friday, causing winds to shift from SW at 5-10 kts early,
to NW at 5-10 kts late. As high pressure builds down into the area
behind this front on Saturday, winds will shift further to the NE,
but remain at relatively weak speeds due to the weak pressure
gradient. Seas will be 2-3 ft Friday with a southerly 5-6 sec wave
being the predominant wave group. By Saturday, wave heights will
fall to around 2 ft, possibly building again late in the period as
some forerunner swell from a developing tropical system well out in
the Atlantic enters the waters.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.
&&
$$
SYNOPSIS...JDW
NEAR TERM...SRP
SHORT TERM...DCH
LONG TERM...JDW
AVIATION...43
Area Forecast Discussion
National Weather Service Lincoln IL
948 AM CDT TUE SEP 27 2016
.UPDATE...
Issued at 945 AM CDT Tue Sep 27 2016
Forecast largely on track and did not require much update. Main
issue was with the amount of dry air in place across the northern
CWA this afternoon. Have backed off on the timing of the minor
rain chances associated with the cold front to our north, and have
largely gone dry this evening except for some isolated showers in
the extreme northern CWA late this evening. Other concerns
addressed in the Fire Weather section below.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 335 AM CDT Tue Sep 27 2016
Flow across central and southeast Illinois will become more cyclonic
into this evening as a surface low pressure area and associated
cutoff upper level low drops south through the Great Lakes region.
Today`s weather should be a repeat of yesterday`s, with mostly sunny
skies, westerly winds gusting up to 25 mph at times, and temps
rising into the lower to middle 70s by this afternoon. As the cutoff
low drops toward the area, clouds will begin to increase this
evening in the north and northeast parts of the CWA. Short term
models also bring a short wave around the back side of the low
pressure area tonight. So will need to add a slight chance of
showers along and north of I-74 for tonight.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 335 AM CDT Tue Sep 27 2016
Cooler than normal temperatures, diurnal cloudiness and a few
periods of light rain showers - mainly in eastern Illinois - will be
the main weather features from mid-week into the weekend. The medium
range models are in slightly better agreement on the position of the
main weather maker, an upper low expected to settle into parts of
the Midwest through the end of the week.
The latest 00z model runs show excellent agreement in dropping an
upper low from Lake Superior to southern Lake Michigan Wednesday,
and then just south of the lower Ohio Valley Thursday. This will
bring a reinforcing cold front and strong low level cold advection
into Illinois. The result will be unseasonably chilly temperatures
for Wednesday with highs struggling to reach the mid 60s. Plenty of
diurnal cloudiness will also develop with the cold air aloft. Will
continue with low chance PoPs for scattered showers in extreme east
central IL/Danville area, with isolated showers/slight chance PoPs
from Galesburg-Lincoln-Mattoon-Lawrenceville and eastward for
Wednesday.
Increased the chance for light rain showers in most of east central
Illinois for Thursday as diurnal cloudiness increases and spokes of
energy rotating around the upper low in central KY provide upper
support. This will also keep temperatures in the upper 60s in
eastern IL, with somewhat warmer readings closer to the IL River
Valley.
Model solutions begin to diverge on the specifics of the upper low
center for Friday and Saturday, with the European continuing to be
further to the west. However, each run of the GFS is also a bit more
to the west. Thus, there is more confidence that eastern IL will
have scattered showers and continued cool temperatures through
Friday. Despite the differences in model solutions for the position
of the upper low, they are also starting to agree that the low will
pull out toward the eastern Great Lakes during the day Saturday.
This should result in only spotty showers late Friday into early
Saturday in eastern IL, followed by a decreasing cloud trend and
gradually warmer temperatures the rest of the weekend. By early next
week, upper level ridging and a southerly low level flow will bounce
us right back into warmer than normal temperatures for the first
full week of October.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 708 AM CDT Tue Sep 27 2016
Conditions at all TAF sites will be similar to yesterday with
clear skies during the day and into the evening hours. An upper
level system in the northern Great Lakes will slide south this
evening and bring mid clouds to all sites beginning around 04-05z
at PIA and BMI, and then after midnight at SPI/DEC/CMI. PIA and
BMI will then see clouds near 5kft after midnight as the upper
level low gets closer toward tomorrow morning. Winds will be
southwest to west through most of the day and evening, but as the
upper level system, and its associated sfc low pressure area gets
closer to the sites, winds will become more northwest. Winds will
also be breezy today with gusts to 22-23kts.
&&
.FIRE WEATHER...
Issued at 945 AM CDT Tue Sep 27 2016
Some concerns with the amount of dry air expected across the
northern half of the CWA this afternoon. Forecast soundings off
the RAP model suggest mixing down from around 850 mb, where dew
points are expected to be in the teens. Large part of the area
yesterday saw surface dew points drop into the 30s. Latest HRRR
guidance shows dew points in the mid-upper 20s north of I-72 which
seems a bit too low, but forecast dew point grids have been
updated to bring a more widespread mid-upper 30s as far south as
Taylorville. 10-hour dead fuel levels still somewhat elevated down
toward the I-72 corridor but are closer to 9-10% across the
northern CWA. Gusts in that area will be close to 30 mph at times
this afternoon. While the fuels do not meet the local red flag
criteria, the dry crops being harvested do pose a risk should any
sparks be triggered by farming equipment. This will be addressed
in the upcoming Hazardous Weather Outlook product.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Auten
LONG TERM...Miller
AVIATION...Auten
FIRE WEATHER...Geelhart
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
626 AM CDT TUE SEP 27 2016
.SHORT TERM... (Through Late Tonight)
Issued at 315 AM CDT Tue Sep 27 2016
Still expect a sunny day as the area will continue to lie under
northwesterly flow aloft with little in the way of moisture through
a deep layer. Went with highs closer to the warmer NAM MOS
temperatures which supports the RAP forecast soundings that show
mixing up into the 850-800 layer by this afternoon. Both the GFS
and NAM are showing a weak upper trough moving through Missouri and
Illinois from the northwest which will bring an attendant surface
cold front into the CWA between 06-12Z. This trough will produce
some weak mid-level ascent, but have no moisture to work with, so
only expect partly cloudy skies with its passage and no rain. Lows
tonight should be close to the MOS lows which match up nicely.
Britt
.LONG TERM... (Wednesday through Monday)
Issued at 315 AM CDT Tue Sep 27 2016
Wednesday morning will see the strong cutoff low moving from near
Chicago southeast across Indiana possibly into western Ohio. The
cold front associated with the surface low should be through our
CWFA by 18Z Wednesday. Models are showing a tremendous amount of
mid-upper level vorticity dropping south over the area on the
western side of the low. Forecast soundings are showing steep low
level lapserates and RH plan views are showing RH values in excess
of 85% between 900-850mb during the late morning and afternoon
behind the front. This suggests there will probably be a decent
strato-cu field behind the front. While MOS PoPs are very low, and
there is no model QPF, I wouldn`t be surprised to see some light
rain showers or sprinkles develop as well...primarily along and east
of the Mississippi. With Strong cold air advection and strato-cu,
ensemble guidance temperatures are probably too warm...so am leaning
heavily toward the cool side of MOS. With the cool start to the
evening and likely clearing sky Wednesday night, lows look likely to
dip into the upper 40s and low 50s which will be the coolest
readings since May for most locations.
Remainder of the week should remain seasonably cool under the
influence of a sprawling Canadian high pressure system. The mid
and upper level cutoff is still forecast to meander over the Ohio
Valley and mid-Appalachians. This will keep the Mississippi Valley
in northwest flow aloft, and block up the pattern so not much will
change probably through at least Sunday. Temperatures should
moderate a bit from Wednesday and Thursday`s coolest readings, but
guidance temps stay a bit below normal through the period and this
looks reasonable given the pattern. Also...would not be at all
surprised to see a few showers or sprinkles east of the
Mississippi each afternoon with the cutoff lurking over the Ohio
Valley. Medium range models have the cutoff finally ejecting
northeast Sunday night and Monday, but am not sure there will be
much change in sensible weather other than a more east-southeast
direction to the surface flow as another trof begins developing
over the Great Plains.
Carney
&&
.AVIATION... (For the 12z TAFs through 12z Wednesday Morning)
Issued at 621 AM CDT Tue Sep 27 2016
Dry and VFR conditions are expected through the period. Westerly
winds will continue through this evening.
SPECIFICS FOR KSTL: Dry and VFR conditions are expected through
the period.
Britt
&&
.FIRE WEATHER...
Issued at 317 PM CDT Mon Sep 26 2016
Winds between 12 and 15 mph and minimum relative humidity between
25 and 30 percent will combine with dry fuels to produce an
elevated fire danger across parts of northeast Missouri and west
central Illinois again this afternoon. Higher relative humidities
and lower wind speeds further south should limit the fire danger
across the rest of the area.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Omaha/Valley NE
610 AM CDT TUE SEP 27 2016
.SHORT TERM...(Today through Thursday)
Issued at 324 AM CDT TUE SEP 27 2016
Quiet weather will continue over the next several days with the
next chance for any precipitation holding off until next week.
Latest water vapor imagery in addition to RAP 500mb analysis shows
a large upper level low spinning over the northern Great Lakes
with a building ridge over the western states. This upper low is
progged to continue to drop south and rotate into the Ohio River
Valley by late Wednesday. A strong vort lobe rotating around the
back side of the low will aid in pushing a westward moving cold
front into the CWA keep highs in the 60s for Wednesday. Otherwise,
the western states upper ridge axis will build east through the
remainder of the week, extending over the Central Plains by early
Thursday. Return flow will be slow to set up across the forecast
area which should keep Thursday`s highs in the upper 60s to lower
70s.
.LONG TERM...(Thursday night through Monday)
Issued at 324 AM CDT TUE SEP 27 2016
Quiet conditions will continue into the weekend with temperatures
near normal for the most part. A more active pattern will take
shape as we head into next week as mid/upper level flow becomes
southwesterly ahead of next approaching trough. Southerly low
level flow should bring increasing moisture into the region with
showers and thunderstorms possible into mid week in association
with several impulses ejecting out ahead of the main trough. A
cold front is progged to dive through the area sometime late in
day 7.
&&
.AVIATION...(12Z TAFS for KOFK...KLNK and KOMA.)
Issued at 610 AM CDT TUE SEP 27 2016
Expect VFR conditions to prevail through the period. Light winds
early this morning will increase from the northwest during the
late morning/early afternoon. Winds should diminish this evening.
&&
.OAX Watches/Warnings/Advisories...
NE...None.
IA...None.
&&
$$
SHORT TERM...Kern
LONG TERM...Kern
AVIATION...Miller
Area Forecast Discussion
National Weather Service Spokane WA
448 AM PDT Tue Sep 27 2016
.SYNOPSIS...
A mild and mostly dry weather pattern is expected through
Wednesday. Temperatures will be above average, with several days
of highs in the mid 70s to mid 80s. Cold front passage on Tuesday
will produce breezy winds down the Okanogan Valley. A pattern
change is expected to arrive late in the week with chances for
showers beginning Thursday and continuing into the weekend. By
Saturday and Sunday, afternoon temperatures will likely be in the
60s...possibly cooling further into the 50s next Monday.
&&
.DISCUSSION...
Today and Wednesday: Satellite imagery shows a cold front moving
across central BC and down across the northern portion of
Vancouver Island. The water vapor channel shows a noticeable dry
slot along the back edge of the front extending out from 130W to
150W in the Gulf of Alaska. The cold front will be fairly slow
moving and become hung up over the region late this afternoon into
this evening. The only precip is expected right up along the
Cascade crest, and will otherwise be too dry at lower levels for
any precip. The main impact with this weather feature will be for
breezy winds down the Okanogan Valley. I decided to favor the
higher resolution model guidance for the winds as they should more
accurately resolve the complex topography across this area. The
ARW, NMM and HRRR models show winds becoming quite breezy through
the Okanogan Valley with winds picking up after 9:00 AM this
morning and peaking in the early afternoon. Expect sustained winds
of 15 to 25 mph with gusts to around 35 mph possible. The
northerly winds will also draw down much drier air with dew points
crashing from the lower 40s to the lower 30s through the
afternoon hours. The combination of breezy winds and low relative
humidity will heighten fire weather concerns for any new fire
starts.
Winds will weaken overnight on Tuesday into Wednesday. The cold
front will generally become hung up over the region with a thin
band of mid to high level clouds stretching across the basin into
the Northeast Mtns and Northern Panhandle. Temperatures will cool
down a bit compared to yesterday but remain above normal for
early fall with highs ranging from the mid 70s to mid 80s. /SVH
Wednesday night through Saturday...We are looking for a quite cool
and unsettled weekend coming. This is courtesy of a deep low
pressure system that will move out of the gulf of Alaska on
Wednesday and move southeast towards the WA/OR coast late in the
day Thursday. The low will then linger off the coast and be the
main weather producer in some form or another well into into next
week. The upper level flow will become southwest Wednesday night
and Thursday and gradually shift to the south as the low
approaches the coast Friday and Saturday. This flow pattern will
tap into some pretty deep Pacific moisture as well. PWATs will
increase to between 0.75 to 0.85 during this period. This is about
160-170 percent of average. The increase in moisture will increase
mid level instability. Lift will mainly be provided by terrain for
an increasing chances of showers Thursday through the weekend. In
addition, numerous short wave disturbances are expected to eject
off the main low and these will be the focusing point for more
intense showers. All of the components are coming together for at
least a chance for thunderstorms for the Idaho Panhandle and
mainly near the border with Montana Friday afternoon. Rainfall
amounts through Saturday afternoon will generally be light with
most of the mountain location seeing between a trace and a tenth
of an inch and little to none for the lower elevations. Snow
levels start out between 9000-11,000 feet on Thursday and are
expected to drop down to between 5000-6000 feet by Saturday. Only
a dusting of snow is expected for the Cascades Saturday morning.
Temperatures on Thursday will be in the 70s and still 5-10 degrees
on the warm side of normal. Temperatures will cool off 4-6 degrees
on Friday and 8-10 degrees on Saturday. High temperatures on
Saturday will have a tough time making it int the lower to mid
60s. Tobin
Sunday to Tuesday: Models begin to diverge on the exact placement
of the upper low as it crosses the region, but generally agree
with it passing on or about Monday. Multiple shortwaves will
rotate around the trough on Sunday and Monday with plenty of deep
moisture to work with, keeping rain likely. Sunday looks wet
mostly for areas around the basin, but the strongest shortwave and
most widespread rain come late Sunday and on Monday. The trough`s
continued influence will keep temps down in the upper 50s and low
60s. A tightening pressure gradient with the passage of a surface
low to the northeast on Monday will also bring gusty winds to the
Columbia Basin. /bwilliams
&&
.AVIATION...
12Z TAFS: A slow moving cold front will sag over the Inland
Northwest today. A narrow band of mid to high level clouds will
form ahead of the front from the Cascade Mtns to as far east as a
line from KPSC to KCOE. Strongest winds with the front will be
down the Okanogan Valley this afternoon that will then spill out
over the Waterville Plateau and into the Moses Lake Area.
Sustained winds of around 20 kts are expected at KOMK weakening to
around 10 kts as these winds reach KMWH in the evening. /SVH
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 78 52 79 55 77 50 / 0 0 0 10 10 30
Coeur d`Alene 78 52 79 54 77 50 / 0 0 0 10 10 30
Pullman 79 52 80 54 76 49 / 0 0 0 10 10 40
Lewiston 85 57 85 59 81 54 / 0 0 0 10 10 10
Colville 79 44 78 48 79 45 / 0 0 0 10 10 10
Sandpoint 75 46 75 49 75 47 / 0 0 10 10 10 20
Kellogg 76 50 79 52 76 48 / 0 0 0 10 10 40
Moses Lake 81 49 80 49 79 45 / 0 0 0 0 0 10
Wenatchee 78 53 78 51 77 49 / 0 0 0 0 0 10
Omak 79 47 78 49 79 47 / 0 0 0 0 0 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion
National Weather Service Phoenix AZ
840 AM MST TUE SEP 27 2016
.UPDATE...
&&
.SYNOPSIS...
A low pressure system over northwest Mexico will slowly move north
through the Desert southwest the next few days. This will lead to variable
cloudiness, cooler temperatures, and a threat of showers and
thunderstorms. Best chances for precipitation look to be today and
tonight. Dry and stable weather will return Friday through next
Monday.
&&
.DISCUSSION...
Looking at current radar, areas of showers and scattered convection
are located along two different max vortices, one in northern Arizona
and another in southern Arizona. For the remainder of the morning, a
little nose of higher MUCAPE along with an area of theta-e
convection will slowly creep northward towards Phoenix, which will
allow shower and storm activity to generate in Pinal county and
primarily south of I-10 in La Paz and Maricopa county. This morning,
the better chances for storms will be in Pinal county where the main
axis and nose of higher MUCAPE values will be. As for the remainder
of the day, another batch of instability driven storms will develop
in south-central and southeastern Arizona, with convective activity
pushing northward (greatest chances for showers and storms from
Maricopa county eastward). With the forecast Phoenix sounding for
this afternoon and evening showing equilibrium levels no higher than
30kft, not anticipating convection to be too strong, however, with
some decent 0-6 km shear and instability forecast, a few stronger
storms may develop and produce small hail and strong winds.
&&
.Previous DISCUSSION...
Today and tonight... Upper low centered
roughly over the northern Sea of Cortez. One of the vort lobes
associated with the low is in southern Arizona. It is helping to
produce a small batch of thunderstorms. The NCAR ensemble picked up
on this development. It goes on to show thunderstorm activity moving
northward and nibbling at the Phoenix metro by mid morning but mostly
stays south of there. Latest HRRR however keeps it south of the
Mexico border but then redevelops activity over Pima County by midday
spreading it into northern Pinal and southwest Maricopa County in the
afternoon. There is some support for this scenario from other hi-res
models (from NCEP and UofA). The main reason for the convection is
cooling aloft (given that we`ve already had moist advection) as the
low drifts northward. Interestingly, despite the deep southeast and
southerly flow, precipitable water is advertised by multiple models
to decline over southern AZ the rest of the morning (especially
portions of southeast AZ). Despite having similar PWAT values, there
are significant differences in the 1000-700mb mean mixing ratios
between the GFS and NAM. The NAM is about 2 g/kg more moist and thus
it has more CAPE. The RAP agrees with the NAM. The SREF shows
increasing CAPE today but median values stay below 500 j/kg over
southern AZ. There will be some CIN to contend with though and thus
PoPs are relatively conservative. SSEO reflects the presence of the
CIN and keeps emphasis of convection south of metro Phoenix today.
There will be enough vertical wind shear for longer lived storms with
more coherent motion than we often see in the Monsoon. SREF shows
median values of 0-6km bulk shear remaining below 30 kts for our area
(but close). Best shear mainly over Cochise and Graham counties where
there will be less moisture. Anticipate some blowing dust issues with
storms moving from Pima County into Pinal and southwest Maricopa this
afternoon. Before the afternoon activity though, we may see some
weaker shower activity as there have been batches of weak echoes
overnight - most noticeably over northern Gila County. With the
approaching vort lobe expect we will see more as the morning
progresses.
Wednesday through Friday...
During the middle and latter part of the week, models show
amplification of the flow pattern over North America and the
northeast Pacific such that anticyclones over the interior West and
northwest Mexico phase up over the Plains while troughing deepens
over eastern North America and the northeast Pacific/western Canada.
In the process, the upper low currently to our south will move slowly
northward and weaken into a short wave and be followed by another
short wave. Lingering moisture and the passing waves keep precip
chances going through Thursday with only very slight chances for our
easternmost areas Friday. The preponderance of the 00Z (plus the 03Z
SREF) indicate that storm activity might be most potent on Thursday
but will mainly be limited to the eastern third of Arizona. Highs
stay near to below normal.
Saturday through Monday...
Dry southwest and westerly flow aloft is in place over the weekend
as the Pacific trough slowly moves inland. Looking at breezy to windy
conditions but nothing overly strong looking yet. Near normal high temps
Saturday then decreasing several degrees by Monday.
&&
.AVIATION...
South-Central Arizona Including KPHX, KIWA, and KSDL:
Upper low spinning to our south will keep elevated amounts of
moisture present across the TAF sites over the next 24 hours, with
variable mid and upper cloud decks mostly aoa 10k feet. Hard to
time/track disturbances rotating around the low will bring mostly
light showers from time to time and due to uncertainly will leave
out precip from TAFs until late this afternoon. Model guidance
suggests somewhat better chance of a shower tonight so will leave a
broad brushed VCSH mention in from around 23Z thru the end of the
taf period. Thunder is possible this afternoon and evening but way
too low confidence factor to include in the TAFs at this time.
Gusty east wind is expected today with best potential for gusts over
20kt from 16z thru 22z. Chance of wind turning to the west later
this afternoon at KPHX is low.
Southeast California/Southwest Arizona including KIPL and KBLH:
Upper low spinning to the south will bring variable mid/high cloud
decks to the area next 24 hours with bases mostly aoa 12k feet.
Winds to favor the north through the east with speeds mostly aob
12kt. There will be an outside threat of mostly light showers off
and on but too low confidence to mention in the TAFs at this time,
also an outside threat for thunder this afternoon/evening but again
too low confidence to put vcts in the TAFs.
Aviation Discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Thursday through Monday...Moist southwest flow aloft will continue
Thursday leading to continued cooler than normal and unsettled
conditions east of the lower Colorado River Valley with the best
chance of showers or afternoon thunderstorms over higher terrain
north and east of Phoenix.
Drier conditions are anticipated Friday and through early next week
as stronger southwesterly flow develops ahead of an area of low
pressure in the Pacific Northwest. Near seasonal normal high
temperatures Friday and Saturday will cool a few degrees below
normal starting on Sunday. Humidity will remain elevated Friday with
most deserts above 20 percent, then a steady drying trend from the
southwest will take place over the weekend and into Monday with
minimum RH values dropping ranging mostly between 10 and 15 percent
by Monday. Winds will follow typical diurnal headings and remain on
the lighter side, with the exception of some afternoon breezes up to
15 to 20 mph in southwest Arizona and southeast California Saturday
and Sunday.
&&
.SPOTTER INFORMATION STATEMENT...
Skywarn radio Net activation will not be needed.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...Hernandez
PREVIOUS DISCUSSION...AJ
AVIATION...CB
FIRE WEATHER...Hernandez/CB
Area Forecast Discussion
National Weather Service Raleigh NC
1020 AM EDT TUE SEP 27 2016
.SYNOPSIS...
A cold front will move into the Carolinas today and will become
quasi-stationary over the area through late in the work week,
bringing unsettled weather through the period.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1020 AM Tuesday
Not making too many changes to the forecast this morning. The cold
front appears to be just barely east of the spine of the
Appalachians, and will combine with modest differential heating,
from both the terrain and morning low clouds in the western
Piedmont/Foothills to be the main focus for scattered showers and a
few storms this afternoon. With highs expected to reach the
mid/upper 70s north to mid 80s south, RAP forecast soundings suggest
an axis of 1000-1500 j/kg MLCAPE through the southern/western
Piedmont during peak heating, and CAM ensembles show scattered
convection moving east into the Piedmont this afternoon. Mid-level
wind fields are still generally weak with the upper low still over
the upper Midwest, but 25-30kt of effective bulk shear in the
vicinity of the front could support a few strong updrafts, and these
would be more likely across the northern portions of the Piedmont.
An isolated flooding threat may exist with some training cells,
though convection is expected to remain mostly north of the areas in
the southern Piedmont that received the heaviest rain last evening.
Widely scattered convection may continue in the presence of the
front throughout the night. Lows tonight 65 to 70.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 358 AM Tuesday...
As the mid/upper level cyclone drifts south into the TN Valley,
models indicate a weak surface wave will develop along the quasi-
stationary frontal zone in place across Western NC. Enhanced low-
level moisture convergence coupled with strengthening vertical lift
from the associated height falls and mid/upper level speed max
spreading east into the area late in the day and into the overnight
hours may lead to the "wettest" period and potentially greatest
heavy rain/flooding threat. The strengthening mid-level flow also
results in improved shear parameters to 30 to 35kts, so cannot rule
out an isolated severe storm Wednesday afternoon. Highs again
in the mid 70 north to lower 80s southeast. Lows in the 60s.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 245 AM Tuesday...
An upper level low over the northern Great Lakes will dig southward
through the OH valley today/Wed, cut-off over the TN Valley Thu/Fri
as an expansive upper level ridge builds over the eastern 2/3 of the
CONUS, then lift northward back to the Great Lakes Sat/Sun as the
ridge breaks down in response to potent shortwave energy digging
southeast from the Pacific NW to the Intermountain West/4-corners
region. What remains of the ridge will shift downstream of the OH/TN
valleys over the Mid-Atlantic/Carolinas early next week as
additional shortwave energy moving ashore the Pacific NW digs SE
through the Intermountain West, further amplifying a deep upper
level trough over the Rockies. With the above in mind, expect
slightly below normal temps Thu/Fri and lingering precipitation in
assoc/w the cut-off upper low possible on Thu. A dry mid-upper level
airmass wrapping around the southern periphery of the upper low will
likely preclude any potential for precipitation on Fri. Dry
conditions and near normal temperatures are expected to prevail for
the remainder of the long term period, Sat/Sun as the upper low
lifts north back to the Great Lakes and Mon/Tue as the
aforementioned ridge aloft shifts eastward from the OH/TN valleys
into the Mid-Atlantic/Carolinas. -Vincent
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
As of 745 AM Tuesday...
The lead pre-frontal band of showers and thunderstorms over the NC Piedmont
will move slowly eastward this morning and into the midday hours,
diminishing/weakening along the way. IFR ceilings in the Triad
should gradually lift to VFR between 15 to 18z, with additional
showers and storms re-developing across western NC and moving
eastward this afternoon and evening as the sfc cold front stalls
across western NC. Sub-VFR ceilings are expected again tonight,
especially in the Triad invof the stalled front.
Looking beyond the 24 TAF Period: The combination of a quasi-
stationary front across the Carolinas and a cut-off upper level low
settling over the Tennessee Valley will keep unsettled weather in the
form of scattered to numerous showers and storms through Thursday.
Drier air from the west should gradually advect east into the area
late Thursday and into Friday, leading to improving conditions
with dry VFR conditions expected Friday and Saturday.
&&
.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 Las Vegas NV
839 AM PDT TUE SEP 27 2016
.SYNOPSIS...An area of low pressure will slowly move up the Gulf of
California and into southeast California by tomorrow afternoon
before lifting into the Great Basin on Thursday. Scattered showers
and thunderstorms will be possible across the area through Thursday
before becoming more localized later in the week. Temperatures will
generally be within few degrees of normal into Saturday.
&&
.UPDATE...Showers trying to move through southern Mohave county and
Colorado River valley having a hard time this morning. An area of
light rain closer to Flagstaff will move towards southern Mohave
county in the next few hours with better chances of reaching the
ground. Cloudy skies look to limit instability with just a few
showers around and only slight chances of a thunderstorm or two by
this afternoon. Overall forecast in good shape, so no updates
planned this morning.
&&
.PREV DISCUSSION...
Issued at 250 AM PDT TUE SEP 27 2016
.SHORT TERM...through Thursday Night.
One area of low pressure is currently located at the northern
portion of the Gulf of California. With that location, easterly flow
is dominant across Mohave and San Bernardino Counties and mid to
high level cloud cover has been enhancing overnight along with a few
light radar returns of which are not yet likely producing any precip
at the surface. During the day expect continued moistening with the
best opportunity of showers and thunderstorms over southeast San
Bernardino, southern Clark and Mohave Counties. The NCAR ensembles
and local hi res models all show a similar depiction with the
operational HRRR being much drier. As the low lifts into southeast
California on Wednesday, a more substantial push of moisture will
advance northward through Mohave County and into southern Nevada
during the day. Most models are indicating modest instability with a
few hundred J/kg and lifted indices of 0 to minus 2. The NAM was
indicating the most instability with values nearly doubled. Expect
Wednesday to be the wettest day across the region with isolated to
scattered thunderstorms across the forecast area and more numerous
showers and storms in Mohave County and the higher terrain of
southern Nevada where brief heavier downpours are possible. The
upper low lifts northward and into central Nevada during the day on
Thursday. Meanwhile, moisture associated with Tropical Storm Roslyn
will work its way into Arizona during the day on Thursday. This will
keep the chance of showers and thunderstorms over Mohave County and
the potential for a more significant rain producer. However, models
are currently keeping the bulk of the moisture further to the east
and in central and eastern Arizona.
.LONG TERM...Friday through Monday Night.
The weather pattern looks to remain active in the extended period
with the possibility of additional troughing influencing the region.
On Friday...southwesterly flow aloft along with some lingering
moisture and instability may promote some isolated to scattered
mountain shower activity across Clark...Lincoln..and Mohave counties
but increasing subsidence and drying aloft should keep things
closely tied to the terrain through the day. Model agreement
decreases over the weekend with ECMWF suggesting a fairly
significant trough digging into the western US while the GFS is
considerably weaker and keeps most of the energy further to our
north. Both solutions would favor breezy conditions and a cooling
trend of some magnitude late in the weekend into early next week.
However...the ECMWF would support a stronger wind episode over the
weekend along with greater cooling associated with a more marked
cold frontal passage. For now I`ve maintained a dry forecast with
modest cooling Sunday into Monday with temperatures falling a few
degrees below normal. I`ve also bumped up wind speeds across the
region as nod towards the ECMWF. If the EC solution maintains some
consistency temperatures may be tweaked downward further as the
event approaches.
&&
.FIRE WEATHER... A low pressure system moving in from the south
today will increase moisture for most of the area by Wednesday.
Shower and thunderstorm chances will initially enter northwest
Arizona and southeast California today...overspread the area
Wednesday...then decrease as the area dries out from west to east
through the end of the week. Some easterly breezes remain possible
across the far western Mojave Desert. There is the potential for a
stronger wind event over the weekend and will be monitoring for
potential fire weather concerns.
&&
.AVIATION...For McCarran...Generally light and variable winds
for the rest of the night. Today will bring light northeast winds,
increasing clouds, with dry weather for the Las Vegas Valley but a
chance of a showers and thunderstorms along the Peach Springs
corridor. Shower and thunderstorm chances increase on Wednesday.
For the rest of southern Nevada...northwest Arizona...and southeast
California...Generally light winds expected area-wide. Some
exceptions may be across the western Mojave Desert where east
breezes may prevail. Increasing clouds and shower/thunderstorm
chances will enter northwest Arizona and southeast California today.
Shower and thunderstorm chances increase across the area on
Wednesday.
&&
&&
$$
Update.....................Steele
Short Term/Aviation/Fire...Czyzyk
Long Term..................Outler
For more forecast information...see us on our webpage:
http://weather.gov/lasvegas or follow us on Facebook and Twitter
Area Forecast Discussion
National Weather Service Duluth MN
312 PM CDT TUE SEP 27 2016
.SHORT TERM...(This evening through Wednesday)
Issued at 240 PM CDT Tue Sep 27 2016
A quasi stationary cut off low, continuing to rotate over Lake
Superior, will finally start to retreat to the south overnight.
The low will migrate into the Chicago vicinity by Wednesday
afternoon.
A swath of rain showers, associated with a corridor of cold
unstable mid level air, is currently pushing southward across the
forecast area as it warps around the low. The rain will gradually
diminish through the night as drier and warmer air returns to the
region through Wednesday.
A few lingering showers will continue over northern wisconsin
Wednesday morning, otherwise skies will gradually clear through
the afternoon and evening time frame. Winds will be out of the
north tomorrow, with gusts around 20 mph across northern
wisconsin. Winds will decrease in strength towards the north and
west. Wednesday will also bring warmer temperatures with afternoon
readings in the upper 50s to low 60s.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 240 PM CDT Tue Sep 27 2016
Summary: A large area of low pressure will dig from the Indiana/Ohio
border area to Kentucky, where it will be cut off and forced to spin
for a while due to block high pressure over the Atlantic Ocean. The
low will then retrograde or lift back north to mainland Michigan or
the eastern Great Lakes into the upcoming weekend. The low will help
maintain easterly flow across the Northland through the weekend, but
temperatures will be slightly warmer than seasonal normals, with
highs primarily in the lower to middle 60s, and low temperatures in
the lower to middle 40s.
Wednesday night...A large, vertically stacked area of low pressure
over the Indiana/Ohio border area, as of Wednesday evening, will
shift to Kentucky, while a ridge of surface high pressure will shift
east into northeast Minnesota. The ridge will help promote clearing
skies across the Northland, but it looks like there will before
lingering low-level cloud cover than previously thought. The cloud
cover will help bolster the temperatures a bit, probably enough to
help stave off the threat of frost across parts of northeast
Minnesota. Temperatures will likely dip into near 40 degrees across
much of northeast Minnesota, and the lower 40s across northwest
Wisconsin.
Thursday through Sunday...The low over Kentucky will get cut off and
blocked thanks to high pressure over the Atlantic Ocean. The low
will spin over Kentucky through Thursday night, then retrograde or
lift back north to mainland Michigan or the eastern Great Lakes into
the weekend. The Northland can expect several days of light easterly
flow and relatively similar weather. The easterly flow will probably
bring some extra moisture from the Great Lakes, so daily afternoon
scattered cumulus is possible. The 4 km NAM is already indicating
this cumulus for Thursday, with a lake breeze pushing the cumulus
inland from Lake Superior.
Monday...Breezy southeast flow will likely develop as low pressure
moves into the Northern Plains from the west. The GFS and ECMWF runs
continue to delay in time when the low and its cold front move
through the Northern Plains and Upper Midwest next week, which will
bring the next chance of precipitation. It now appears the
precipitation would not affect the Northland until late Monday or
even Tuesday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1239 PM CDT Tue Sep 27 2016
A large area of low pressure over eastern Lake Superior is
resulting in cool northwest flow, widespread MVFR ceilings, and
light rain across northeast Minnesota and northwest Wisconsin, as
of early this afternoon. The low will move south through the Great
Lakes region, which will shift the current light rain to the south
and east by later today. However, the low ceilings are expected to
linger into Wednesday morning, at times becoming IFR this evening
and overnight.
High pressure will begin to shift into the region Wednesday,
helping to clear out the region. There could be a period of MVFR
ceilings late Wednesday morning and early afternoon from
widespread broken cumulus clouds until better lifting and clearing
of the clouds occurs later in the afternoon.
There could be a brief period of significant low-level wind shear
at KHYR late tonight, shortly before and around dawn. The hourly
RAP model is indicating an impulse of stronger north-northeast
flow aloft, nearly 35 knots, could pass through the KHYR area over
a 3-hour window. May need to add LLWS with subsequent forecasts.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 48 60 44 62 / 60 10 0 0
INL 44 59 40 66 / 20 10 0 0
BRD 46 60 41 65 / 20 10 0 0
HYR 47 60 44 66 / 80 20 0 0
ASX 51 58 47 63 / 70 30 0 0
&&
.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...Small Craft Advisory until 4 PM CDT Wednesday for LSZ146-147.
Small Craft Advisory from 4 AM to 4 PM CDT Wednesday for LSZ144-
145.
Small Craft Advisory from 10 PM this evening to 4 PM CDT
Wednesday for LSZ140>143.
Small Craft Advisory until 10 PM CDT Wednesday for LSZ121-148.
&&
$$
SHORT TERM...Graning
LONG TERM/AVIATION...Grochocinski
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
652 PM EDT Tue Sep 27 2016
.SYNOPSIS...
An area of low pressure will move northeast just off the coast
tonight. A stalled cold front to the northwest will gradually
dissipate Wednesday and Thursday. Another cold front will
gradually move through the area over the weekend as low pressure
over the Ohio Valley moves northeast.
&&
.NEAR TERM /TONIGHT/...
As of 650 PM Tuesday...Latest sfc analysis shows weak low off the
NC coast this evening...and cold front extending from SW VA down
into the deep south. Latest radar imagery shows line of showers
and isolated thunderstorms extending from the western Albemarle
Sound down to Beulaville. Adjusted pops for the next few hours
based on radar trends...best chances across the southern zones as
line pushes eastward. High res models HRRR and NSSL WRF show bulk
of precip diminishing shortly after 00z this evening with loss of
heating...though isolated showers/tstm threat will persist through
overnight hours with moist unstable conditions and weak short wave
energy along with low moving northeast just off coast. Will
continue chance POPs all zones. Some concern for fog inland
sections overnight if there is some clearing in areas that will
receive rain this evening. Will continue patchy fog mention. Min
temps from upper 60s inland to lower 70s coast.
&&
.SHORT TERM /WEDNESDAY/...
As of 400 PM Tuesday...Weak high pressure will be over area in
the morning in wake of low pressure moving off to northeast and
have lowered POPs to just lower chance early. Upper low dipping
into Ohio Valley will produce additional short wave energy across
area late morning through afternoon and area will return to warm
sector conditions as surface winds return to southerly as low
pressure develops to west. Scattered showers and tstms will
develop and some storms could be strong to marginally severe as
increasing instability and shear may result in wind gust threat.
Will carry higher chance POPs through afternoon. Max temps in the
low to mid 80s.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
As of 400 PM Tuesday...Minor update for slightly warmer temps
Sunday-Monday.
/Previous discussion/
As of 3 AM Tue...Unsettled through Thu then a bit drier by the
weekend.
Wed through Thu...Weakening cold front will cont over the region
Wed and Thu as big upr low conts to the NW. Axis of good moisture
will remain over eastern NC leading to at least chc of shra and
poss a few tsra. Best chcs will be inland Wed and have pops just
below likely. Precip may become a bit more sct into Thu and have
lower chc pops area wide. Temps close to seasonal for late Sept
with highs 70s to lower 80s and lows 60s inland to around 70
beaches.
Fri through Tue...The upr low to the NW will slowly move NE into
the weekend as sfc front conts to dissipate. Drier mid lvl air
will spread in from the W Fri with slight chc of shra over ern
portions of the area. Not much change Sat into Mon with mdls
keeping bulk of moisture near cst and offshore so will cont slight
pop imd cst and dry inland. Highs will cont near seasonal lvls
with upr 70s to around 80.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
Short Term /through Wednesday/...
As of 650 PM Tuesday...VFR conditions at TAF sites will generally
persist into this evening with weak warm sector conditions between
low pressure offshore of SC and weak cold front approaching from
W-NW. Main line of showers will impact ISO/EWN/OAJ through 00/02z.
Light winds and some clearing possible for inland sites overnight
and will continue to indicate MVFR conditions developing with fog
and stratus. IFR will be possible but confidence remains low at
this time. Any fog and stratus should lift between 12-14z with VFR
returning. Scattered showers and thunderstorms expected to develop
Wed afternoon.
Long Term /Wed night through Sunday/...
As of 3 AM Tue...Decent coverage of shra into Thu with poss some
isold trsa. The precip will lead to a few periods of sub VFR thru
Thu. Drier air will work in from the W Fri with decreasing chc of
shra and mainly VFR thru Sun...there will be threat of some late
night and early morning fog and stratus with light winds late
week.
&&
.MARINE...
Short Term /through Wednesday/
As of 650 PM Tuesday...Latest obs show NE-SE winds 5-15 kt and
seas 2-4 feet. No sig changes made to previous forecast at this
time. Low pressure approaching from south is fairly weak but is
producing max 3 hourly pres falls near Diamond Shoals, resulting
in persistent east winds gusting to around 20 KT and seas up to 5
FT. NAM is only model indicating this and has speeds that areas
around 15 KT into overnight hours, and persistent gusts will
likely produce seas to 6 feet. Posted SCA central waters through
late tonight but confidence moderate at best.
Low moving NE just offshore will result in current E-SE winds
backing to NE and N overnight with speeds rest of waters mainly
below 15 KT and seas 2-4 FT. Weak high pressure over area in the
morning will move offshore in afternoon with winds returning to
SE-S 10-15 KT with seas remaining 2-4 FT.
Long Term /Wed through Sunday/...
As of 3 AM Tue...Light mainly NNE winds in wake of low early Wed
quickly returns to light S or SE later in the day with weakening
cold front to the W. Predominately S to SW winds 15 kts or less
Thu into Fri as dissipating front drifts to the cst. Light winds
Sat with the front or whats left of it near cst. Seas thru the
period will be mainly 2 to 4 feet...could flirt with 5 ft at times
far outer waters.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Beach Hazards Statement until 8 PM EDT this evening for NCZ095-
103-104.
Beach Hazards Statement from Wednesday morning through
Wednesday evening for NCZ103.
MARINE...Small Craft Advisory until 8 AM EDT Wednesday for AMZ152-154.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM/CQD
SHORT TERM...JBM
LONG TERM...RF/JBM
AVIATION...RF/JBM/CQD
MARINE...RF/JBM/CQD
Area Forecast Discussion
National Weather Service Marquette MI
352 PM EDT Tue Sep 27 2016
.SHORT TERM...(This evening through Wednesday)
Issued at 352 PM EDT TUE SEP 27 2016
12Z raobs/latest wv imagery and RAP analysis show a closed upr lo
dropping slowly swd acrs Lk Sup. Deep cyc, cool flow arnd this
disturbance in concert with deep mstr depicted on the 12Z INL raob
and some dynamic forcing are generating some showers over the cwa
this aftn. With the cld cover and h85 temps arnd 4C /Lk Sup temps
range fm about 10-15C/, there is some lk enhancement to the pcpn
as temps are holding in the upr 40s to mid 50s. There is some drying
evident wrapping arnd the closed lo associated with large scale
subsidence/deep lyr qvector dvgc on the nrn flank of that feature
that is tending to diminish the shower coverage over much of Lk Sup
and the nrn land cwa.
Tngt...Closed lo fcst over scentral Lk Sup early this evng is
progged to sink steadily swd to over scentral Lk MI by 12Z Wed, with
large scale subsidence/deep lyr qvector dvgc/mid lvl drying
overspreading Upr MI fm the n. With these trends in mind, expect the
showers to become more sct by later tngt. Although the h85-lk
temp difference wl be marginal for lk effect pcpn, lingering llvl
mstr and the sharp cyc flow should still support some showers. Since
winds wl also shift steadily to a more cyc ne direction during
the ngt with the passage of the sfc lo to the s of the cwa, expect
the lk effect showers to become most nmrs over the w and ncntrl cwa,
where this ne flow wl upslope. There could still be some waterspouts
late this aftn into the evng hrs over mainly the scentral portion
of the lk to the Keweenaw under lingering deeper mstr/area of lighter
winds near the sfc lo center and where the hier res models indicate
mucapes as hi as 500-750j/kg over the somewhat warmer nearshore
waters. But rising hgts/mid lvl drying and lowering mucape/hier winds
on the nrn flank of departing sfc lo wl diminish this threat after
the evng. The arrival of the ligher winds closer to the track of the
sfc lo wl also bring the threat of waterspouts to the Lk MI
nearshore waters tngt.
Wed...With continued hgt rises/mid lvl drying/lowering subsidence
invrn/slowly weakening cyc nne flow to the n of the closed lo
sinking into the Lower Lks, the shower coverage wl diminish. The
best chc for more persistent showers wl be over the hier terrain
of the w and ncentral cwa impacted by upsloping and over the far
se on the nw edge of some lingering deeper mstr closer to the
departing closed lo to the sse. Even though the shower coverage wl
diminish, fcst llvl mstr/sfc obs upstream sug a good deal of lo clds
wl linger and limit diurnal temp recovery.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 332 PM EDT TUE SEP 27 2016
High pressure building in from the northwest Wed night and Thu
should end showers and allow for decreasing clouds. The NAM and GFS
soundings indicate that there could be some near sfc moisture
trapped beneath strengthening subsidence inversion Wed night into
early Thu which could maybe lead to some stratus formation for
locations favored by upslope ne flow. Models indicate there should
be enough wind/mixing to preclude fog formation so removed patchy
fog for western counties Wed night into early Thu. Cut-off mid-upper
level low pressure system remaining nearly stationary over the TN
River Valley should maintain dry conditions through Fri. Expect mins
Wed night and Thu night to range from lower 40s interior west to mid
50s near Lake Superior in onshore ne flow. H85 temps of 7-8C should
support inland max temps mainly in the mid to upper 60s on Thu and
H85 temps of 8-10c should support inland max temps in the upper 60s
to lower 70 on Fri. Continued onshore ne flow will keep max temps
cooler both days near Lake Superior in the lower to mid 60s. Influx
of mid-Atlantic moisture wrapping around cut-off low could lead to
increase in mid-level clouds on Fri over the southeast half of U.P.
Models in general agreement with mid-upper low moving slowly
northward into the Ohio Valley/Great Lakes region Fri night into the
weekend and getting eventually caught back in westerly mid-latitude
flow in response to deepening mid-upper trough over the West Coast.
Continued influx of deeper mid-Atlantic moisture wrapping around low
and increasingly cyclonic ne flow will lead to increased chances for
rain beginning Fri night and continuing into the weekend especially
for the east half of Upper Mi closer to the movement of mid-upper
low.
Model trends indicate closed low slowly moving east toward New
England Sun night into Mon as western CONUS trough moves slowly
eastward. Should see improving weather across Upper Michigan Sun
night into Mon as upper level ridging from west becomes main feature
again. Expect increasing clouds from the west late Mon night into
Tuesday as mid-level moisture increases with approach of mid-upper
trough from western CONUS and associated sfc trough from the Plains.
Some increase in mid-level q-vector convergence ahead of the trough
could also bring some light rain into west and central Upper Mi on
Tue. Not surprisingly the 12z GFS is showing its typical bias with a
quicker advance of trough than the 12z ECMWF so will include some low
chance pops for rain over west and central counties mainly Tue
afternoon.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 142 PM EDT TUE SEP 27 2016
A deep, moist cyc flow arnd a slow moving lo pres system sinking
slowly s thru the Upr Great Lks will bring some showers and MVFR
conditions much of the time thru tngt. The best shot at IFR
conditions wl be at IWD due to a more favorable upslope nw veering n
wind component and longer air trajectories down wrn Lk Sup.
Downslope nature of the nw flow into SAW may lead to vfr conditions
at times this aftn. Although the arrival of drier air aloft and a
weakening cyc flow wl tend to diminish the showers on Wed, lingering
llvl mstr/upslope nne winds wl lead to continued MVFR cigs.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 332 PM EDT TUE SEP 27 2016
As low pressure over eastern Lake Superior weakens and sinks slowly
south of the area through Wednesday, the pressure gradient over the
lake will gradually slacken causing north-northeast winds to 30
knots tonight over west and north central Lake Superior to diminish
to 20 to 25 knots on Wed. There could be some gale gusts to 35 knots
tonight mainly over the western half of Lake Superior. With the slow
approach of trailing high pressure, the winds will continue to
diminish late Wed into the weekend with lighter east to northeast
winds under 20 kts expected.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...KC
LONG TERM...Voss
AVIATION...KC
MARINE...Voss
Area Forecast Discussion
National Weather Service Phoenix AZ
154 PM MST TUE SEP 27 2016
.SYNOPSIS...
A low pressure system over northwest Mexico will continue to slowly
move north through the Desert southwest the next few days. This will
lead to variable cloudiness, cooler temperatures, and a threat of
showers and thunderstorms through Thursday. Best chances for
precipitation look to be tonight through tomorrow morning. Dry and
stable weather will return Friday through next Monday.
&&
.DISCUSSION...
Current satellite imagery is exhibiting the center of an upper level
low pressure system over northwest Mexico with south-southeasterly
flow on the eastern periphery continuing to advect a more unstable
atmosphere into the desert southwest. Current light shower activity
in northern Maricopa county and parts of southeast California will
continue to fizzle out as it moves to the north and west. For the
remainder of the afternoon and evening, showers and thunderstorms
will redevelop in southeast Arizona and then gradually move
northward.
Convective inhibition will continue to gradually decrease this
afternoon allowing scattered to numerous showers and thunderstorms
to develop over southeast Arizona within the next couple hours. The
HRRR and a few ensemble members have a good handle on the situation,
initiating activity near the Mexico border by mid afternoon, with a
gradual push of these showers and storms to the north. However, by
the time activity reaches the southern part of our CWA, storms
should become more sparse with mostly showers embedded with isolated
thunderstorms. Then for the rest of the evening into tomorrow morning,
activity slowly fizzles out over the lower deserts, then pushes east
towards the higher elevations in southern Gila County.
At the moment, dewpoints in the upper 40s/low 50s are resulting in
only slight instability, with MLCAPE values currently between 100 and
500 J/Kg and the greatest instability in east and southeast Arizona.
However, DCAPE values will be near or greater than 1000 J/Kg, so any
thunderstorm that does develop will have the potential to produce a
strong downdraft resulting in strong outflow winds. On the topic of
outflow winds, the HRRR and the HRRRX (although the HRRRX is a bit
stronger) are both indicating an outflow boundary pushing northward
from distant thunderstorms in southeast Arizona. Anticipate some
blowing dust issues with storms moving from Pima County into Pinal
and southwest Maricopa this afternoon. In addition to strong winds
and dust, there may be enough vertical wind shear for longer lived
and a bit more organized storms with more coherent motion than we
often see in the Monsoon; thus, stronger storms may have the
potential to produce small hail as well.
Wednesday through Friday...
During the middle and latter part of the week, models show
amplification of the flow pattern over North America and the
northeast Pacific such that anticyclones over the interior West and
northwest Mexico phase up over the Plains while troughing deepens
over eastern North America and the northeast Pacific/western Canada.
In the process, the upper low currently to our south will move slowly
northward and weaken into a short wave and be followed by another
short wave. Lingering moisture and the passing waves keep precip
chances going through Thursday with only very slight chances for our
easternmost areas Friday. The preponderance of the 00Z (plus the 03Z
SREF) indicate that storm activity might be most potent on Thursday
but will mainly be limited to the eastern third of Arizona. Highs
stay near to below normal.
Saturday through Monday...
Dry southwest and westerly flow aloft is in place over the weekend
as the Pacific trough slowly moves inland. Looking at breezy to windy
conditions but nothing overly strong looking yet. Near normal high temps
Saturday then decreasing several degrees by Monday.
&&
.AVIATION...
South-Central Arizona Including KPHX, KIWA, and KSDL:
A large low pressure system over northern Baja CA will slowly move
north toward southern CA through Wed afternoon. This system
continues to tap a pool of Mexican moisture which is forecast to
rotate cyclonically around the low pressure system and into southern
AZ through Wednesday afternoon. Through 20z Wed, east winds 5 to 12
knots. Sct clouds 10-14 thsd ft AGL with vrbl cirrus above. Slight
chance of a sprinkle or light shower.
Southeast California/Southwest Arizona including KIPL and KBLH:
A large low pressure system over northern Baja CA will slowly move
north toward southern CA through Wed afternoon. This system
continues to tap a pool of Mexican moisture which is forecast to
rotate cyclonically around the low pressure system and into
southeast CA and southwest AZ through Wednesday afternoon. Through
20z Wed, north to north winds 5 to 12 knots. Sct clouds 10-14 thsd
ft AGL with vrbl cirrus above. A slight chance of a sprinkle or light
shower.
Aviation Discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Friday through Tuesday...
A drier and more stable atmospheric airmass will spread into the
region under westerly flow aloft. Mostly clear skies are forecast
with seasonably warm afternoon temperatures. Minimum relative
humidities will slowly fall from around 20 percent Friday to around
15 percent Monday and Tuesday. Afternoon southwest winds 5 to 15 mph
are expected each day. Recovery will be excellent.
&&
.SPOTTER INFORMATION STATEMENT...
Skywarn radio Net activation will not be needed.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...Hernandez/AJ
AVIATION...Vasquez
FIRE WEATHER...Vasquez
Area Forecast Discussion...Corrected Duplicate Groups
National Weather Service Tampa Bay Ruskin FL
231 PM EDT TUE SEP 27 2016
.SYNOPSIS...
Ridge axis of weak high pressure extended across the Florida Straits
with westerly low level flow across forecast area. Visible satellite
and surface observations showed sea breeze front from Inverness to
Sarasota then down to Naples. Isolated showers were found along the
front. Water vapor loop showed weak upper level low in east central
Florida with drier air wrapping into the forecast area. Best chance
of aftenoon storms to be in Highlands County as it is closer to the
deep layer moisture across south Florida.
.SHORT TERM (Tonight and Wednesday)...
Will keep a small chance of thunderstorms in forecast 00-03Z east of
Highway 27 in Polk and Highlands counties and in Punta Gorda and
Fort Myers as HRRR model has gust front from Highlands County
convection heading back to the coast.
Large and stacked upper level low centered near eastern Lake
Superior is forecast to drift south into Indiana Wednesday. Our
forecast area will be on the southern end of the cyclonic flow
aloft. Weak impulses in this flow combined with a stalled front in
the Florida Pan Handle will bring scattered showers and storms to
the Nature Coast late tonight and will continue through the
afternoon. Expected cloud cover and sea breeze will keep highs in
the mid 80s rather than the upper 80s in this area. Elswhere,
westerly low level flow will be a bit stronger Wednesday with the
sea breeze front moving well inland. Best chance of storms will be
east of Interstate 75 from 18-21Z.
.MID TERM/LONG TERM (Wednesday Night-Tuesday)...
A mid/upper level low meanders between the Great Lakes and the
Tennessee Valley through most of the weekend. The low nudges a
weakening frontal boundary out of the Deep South...through northern
FL on THU...then into central FL where it dissipates during FRI. A
ridge of high pressure from the Atlantic initially across south FL
slides off to the east. The front settles in with drier and more
stable air behind it...with limited to nil rain chances from around
the I-4 corridor northward. South of there scattered showers and
storms will continue. Some deeper moisture will begin to creep back
north SAT. Temperatures will run around normal for the highs.
However lows for the nature coast will be just below normal while
lows south of I-4 stay on the warm side.
On SUN the upper low tracks across the lower Great Lakes to NY or
southwest Quebec by MON. For TUE the low remains near NY (GFS) or
pushes east to the Canadian Maritimes (ECMWF). At the surface...
Atlantic high pressure builds back in across and north of the state
as a low approaches... near the Bahamas (GFS) or central Cuba
(ECMWF)...at the very end of the period. Moisture will significantly
increase and spread northward as low level flow takes on an easterly
component. Showers will be scatted to numerous with isolated to
scattered thunderstorms. High temperatures will be near to a bit
above normal. The lows will be a degree or two above normal.
The last day or so of this forecast could change depending upon the
exact track of the low...in the Bahamas or near Cuba?
&&
.AVIATION...
VFR conditions for most of the next 24 hours. Best chance for
afternoon storms this afternoon and Wednesday afternoon will be east
of the terminals as a westerly low level flow pushes the Gulf Coast
sea breeze inland.
&&
.MARINE...
A cold front will move into the coastal waters Thursday and will
wash out. This will bring scattered showers and thunderstorms to the
central and northern coastal waters through Thursday. Easterly flow
develops for the weekend with late afternoon and overnight showers
and storms.
&&
.FIRE WEATHER...
Relative humidity is forecast to remain above critical thresholds
through the week, with no fire weather concerns expected.
&&
.Preliminary Point Temps/PoPs...
TPA 76 88 75 87 / 10 30 40 40
FMY 74 89 75 88 / 30 30 30 40
GIF 73 89 73 87 / 10 50 20 50
SRQ 76 87 76 87 / 10 30 40 50
BKV 72 87 72 86 / 20 50 40 50
SPG 78 87 77 86 / 10 30 40 50
&&
.TBW Watches/Warnings/Advisories...
FL...Beach Hazards Statement through Thursday evening for
Coastal Manatee-Coastal Sarasota.
Gulf waters...None.
&&
$$
SHORT TERM/AVIATION/MARINE/FIRE WEATHER...72/Noah
MID TERM/LONG TERM/DECISION SUPPORT...09/Rude
Area Forecast Discussion
National Weather Service Tucson AZ
305 PM MST TUE SEP 27 2016
.SYNOPSIS...An area of low pressure aloft will provide a chance of
showers and thunderstorms through Thursday. A slight chance of
showers and thunderstorms Friday will exist east of Tucson, then dry
conditions will prevail this weekend into early next week.
&&
.DISCUSSION...Scattered showers and thunderstorms extended from the
central/southern portion of the Tohono O`odham Nation southeastward
into western Santa Cruz County at this time. Movement of these
showers and thunderstorms was to the north at 25-30 mph. This area
of showers/tstms is well handled via the 27/12Z Univ of AZ WRF-NAM
and GFS. The 27/20Z HRRR was too far southeast with this area of
showers/tstms valid at the current time.
Expect scattered showers/tstms this evening ahead of an upper low
pressure system centered over far northwest Sonora Mexico. The upper
low is progged to fill while moving northwest into southern
California Wednesday morning. The hi-res models suggest that
isolated showers/tstms will continue late tonight. A north-to-
south axis of deeper moisture will maintain isolated to scattered
showers/tstms mainly from Tucson eastward Wednesday and Wednesday
night.
Meanwhile, Tropical Storm Roslyn located at 18.8N/116.6W (or about
515 miles WSW of the southern tip of Baja California) valid 2 PM MST
this afternoon is expected to weaken to a remnant low in about 24
hours. However, the 27/12Z GFS/ECMWF/CMC depict some moisture from
this system to be entrained northeastward across the area Thur.
Thus, precip chances are expanded further west Thur versus Wed to
include the entire forecast area.
Isolated to scattered showers/tstms should continue Thur evening,
then a drying trend will ensue from west-to-east Friday as
southwesterly flow aloft increases. A slight chance of showers/tstms
continues across eastern sections Friday afternoon/evening.
Thereafter, the GFS/ECMWF/CMC were similar with depicting a
deepening upper low over the Pacific Northwest this weekend, then
moving this system eastward across the northern Rockies/northern
CONUS Plains Mon-Tue. Stronger westerly flow aloft will shunt the
deeper moisture well east of the area. Thus, dry conditions to
prevail Sat-Tue.
High temps Wed are forecast to be about 5-10 degs warmer versus
temps achieved this afternoon. A few degs of additional warming will
occur Thur followed by no significant change in daytime temps Fri-
Sat. A very minor moderation in daytime temps is on tap early next
week, with high temps trending a few degs below normal.
A warming trend will occur Tue-Thur followed by no significant
change in daytime temps Fri-Mon. The upshot is that high temps
Thursday into early next week will trend closer to seasonal normals
for late Sep/early Oct.
&&
.AVIATION...Valid through 29/00Z.
Scattered -TSRA/-SHRA this evening followed by a slight chance of
-TSRA/-SHRA late tonight into Wednesday morning. Isolated to
scattered -TSRA/-SHRA to prevail Wednesday afternoon KTUS vicinity
east to the NM border. Otherwise, cloud decks generally 6k-10k ft
AGL, and surface wind easterly to southerly at 5-15 kts with gusts
to 25 kts. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...A chance of thunderstorms exists area-wide through
Thursday evening, then a drying trend will begin late Thursday and
continue into this weekend. A slight chance of showers and
thunderstorms Friday will continue east of Tucson followed by dry
conditions Saturday through next Tuesday. Expect occasionally gusty
east winds through Thursday, then normal diurnal wind trends to
prevail Friday into early next week.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE
&&
$$
DISCUSSION...Francis
AVIATION/FIRE WEATHER...Meyer
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson