Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/08/19
AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
945 PM EDT Mon Oct 7 2019
.SYNOPSIS...
A weakening cold front crosses the region overnight. The front
will stall along the coast on Tuesday as low pressure lifts
north off the Carolina coast.The low will then stall off the mid
Atlantic coast through Friday.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 945 PM EDT Monday...
Latest sfc analysis depicts developing low pressure offshore of the
SC coast. A cold front was located from the New England coast to the
NW VA Piedmont to the mountains of SC, and ~1024 mb high pressure
was centered over nern KY/srn OH. While the bulk of the post-frontal
rain is in MD/PA, radar imagery shows isolated showers just behind
the front N of Louisa County and across NE NC. An area of heavier
rain (associated w/ deeper moisture near the developing sfc low) was
just off the coast of SE NC. 9 PM temperatures were still in
the low 70s in most areas ahead of the front, with mid 60s
behind the front in Louisa County.
Models remain in good agreement with the timing of the front
overnight, generally shifting the winds from a light SE to a
stronger NNE direction between now and 06Z over the NW 1/2 of the
CWA, and between 06Z-09Z across SE VA/NE NC. The general idea of of
the front continuing to weaken as it crosses the mountains (and
eventually the entire CWA) has stayed the same. Thus, PoPs will be
mostly kept in the 30-50% range for scattered showers later tonight.
With the sfc low off the SE coast lifting N overnight, some deeper
moisture may be able to move into far SE VA and NE NC with the
frontal passage between 06-12Z. However, the latest 00z (and
previous few) runs of the HRRR are forecasting the vast majority
of pcpn from 06-12Z associated w/ the sfc low to stay offshore
of the SE VA/NE NC coast. Thus, lowered PoPs slightly (to
30-50%) across the far sern zones from 06-12Z as the other hi-
res guidance and latest 18Z NAM/GFS support the idea of less
pcpn coverage across the SE. Regardless, still some notable
differences in model QPF: the 12Z ECMWF and 12Z NAM showed a lot
of QPF into NE NC and far SE VA Tue morning. As mentioned above,
the 18Z NAM, GFS, and majority of high res guidance including
the 12Z HREF shows much less in the way of QPF throughout. Will
continue to show a little more QPF in the SE on Tue, but still
well below what the 12Z ECMWF depicts. Lows tonight range from
the mid-upr 50s NW zones to the mid-upr 60s SE zones. It will be
significantly cooler on Tue with a strong NNE low level flow
(especially near the coast). Highs will be in the lower 70s SE,
but mainly staying in the 60s elsewhere. In between the sfc low
off the coast and an upper trough hanging bacK W of the Mtns,
PoPs by late morning and aftn will only be 20-30% except for
higher chances along the coast. It should be overcast throughout
the area.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 350 PM EDT Monday...
GFS/NAM/ECMWF are in decent agreement through this period
although they differ somewhat with respect to the precise
location of the upper trough and the coastal low. Raised PoPs a
little bit for Tue night/early Wed as the upper trough moves
across the northern zones during this period (PoPs 30-40% most
areas). Still looks like QPF is fairly limited with the sfc low
well off the coast. Cool again Wed with highs mid-upper 60s most
areas, lows Wed night lwr 50s- lwr 60s. By Thus, will still
maintain chance PoPs E and 15-20% to the west. May start to see
a little more in the way of breaks in the clouds Thu (esp W of
I-95) but still a little cool with highs upper 60s to lower 70s.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 345 PM EDT Monday...
The extended period (Thu night) will start with low pressure (sfc-
aloft) a couple hundred miles off the Mid-Atlantic coast. At the
same time, upper ridging will be anchored from the central Atlantic
to the Canadian Maritimes while deep upper troughing prevails over
the ern Rockies/High Plains. With upper ridging remaining over the
Canadian Maritimes, the low just offshore of our area is not
expected to move much through Fri night. This will result in
continued chances for showers (PoPs of 15-25% from 00z Fri-12z Sat)
near the coast with northerly flow at low levels. Expect
dry/seasonal conditions inland from Thu night-Sat AM. Still not
expecting a whole lot of QPF during this timeframe though. Rain
chances (near the coast) come to an end by late Sat as the low
finally moves well offshore as upper ridging over the Canadian
Maritimes starts to break down. The area of deep upper troughing
(and strong sfc low pressure) that was over the Rockies/High Plains
moves into the Upper Midwest by early Sat AM. The low moves over the
wrn Great Lakes by Sun while the (weakening) trailing cold front
approaches the area. The GFS shows the potential for a few showers
near the coast by late Sun, but the other models keep it dry through
the weekend. For now, added slight chc PoPs for coastal/SE zones on
Sun.
High temperatures Fri range from the upper 60s on the Lower MD Ern
Shore to the low 70s elsewhere. Slightly warmer from Sat-Mon, with
highs mainly in the 72-77F range. Morning lows from Fri-Sun will
mainly be in the 50s for most areas with low 60s across coastal SE
VA/NE NC. Forecast lows are in the mid-upper 40s inland/50s near the
coast on Mon AM.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
As of 750 PM EDT Monday...
VFR conditions will continue for the next few hours with SCT-BKN
clouds in the 4-7k ft range. Winds are mainly SE at the
terminals, with a cold front over nrn/wrn sections of VA moving
to the SE. Still a few showers across interior NE NC, but these
are not expected to affect the terminals during the next few
hours. The aforementioned cold front will cross the terminals
from NW to SE from 03-08z. As the front crosses the area, expect
some scattered showers but the coverage is not high enough to
include anything more than VCSH wording in the TAFs at this
time. The winds will abruptly shift to the N-NE as early as
03-04z at RIC/SBY, but not until ~08-09z at ECG. CIGS lower to
1000-1500 ft shortly after the FROPA, with all VA/MD terminals
seeing CIGS in this range by 09z. All terminals are expected to
see low-end MVFR CIGS on Tue. There is a chc for IFR CIGS at
RIC/PHF/ORF (mainly from 12-18z Tue), but confidence in
prevailing IFR CIGS is low attm. The chc for scattered showers
will continue through much of the day on Tue (especially SE),
but not expecting VSBYS to drop to anything worse than MVFR. NNE
winds become rather strong near the coast with gusts to 25 kt,
and to around 20 kt inland.
OUTLOOK... Low pressure lingers offshore of the VA/NC coast from Tue
night through Thu/Fri. Therefore, expect flight restrictions to
continue into at least Wed and potentially through Thu night (mainly
due to CIGS). Winds will stay elevated from the N/NE during this
period as well.
As a side note, we have not received any METAR data from ORF since
the mid-morning (1251z), but TAFs will be amended if needed
until the issue is resolved.
&&
.MARINE...
As of 345 PM EDT Monday...
High pressure is located well off the Mid-Atlantic coast this
afternoon, with a cold front still to the NW of the region. As the
cold front approaches the waters later this afternoon and evening,
winds will remain SSE 5-15kt, with 4-5 ft seas and waves ~2 ft in
the Bay. The cold front will cross the region later tonight into
early Tuesday morning. The wind will become N 15-25kt behind the
front, and will continue into Wednesday as high pressure builds N of
the region. SCAs will begin in the Ches Bay and lower James by 08z
early Tuesday morning, and the Currituck Sound and remaining rivers
by 11z Tuesday...lasting through Wednesday (4th period for now).
Current SCAs for the ocean will run through Wednesday as well (for
now). Low pressure develops off the coast by midweek while strong
high pressure remains centered N of the region. A N wind of 20-30kt
is expected for the ocean/Bay/Sound, and 15-25 kt elsewhere. Solid
SCA conditions will continue, and a period of low-end gale
conditions (at least in gusts) is possible, especially for the ocean
from late Wednesday into Friday morning. Seas are forecast to build
to 6-11 ft during this time-period.
&&
.TIDES/COASTAL FLOODING...
As of 345 PM EDT Monday...
The combination of high pressure north of the region and low
pressure developing off the coast will result in a prolonged N to NE
wind Tuesday through Friday. This will result in increasing tidal
anomalies, which could potentially reach 1.5-2.5 ft above normal
by Wednesday into Thursday and Thursday night.
A high Risk of Rip Currents remains in effect through Tuesday due to
a combination of elevated seas and long period swells. The Rip
Current Risk will likely remain elevated throughout the week.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory from 7 AM Tuesday to 7 PM EDT Wednesday
for ANZ633-635>637.
Small Craft Advisory until 7 PM EDT Wednesday for ANZ630>632-
634-638-650-652-654-656-658.
&&
$$
SYNOPSIS...LKB
NEAR TERM...ERI/LKB
SHORT TERM...LKB/MPR
LONG TERM...ERI
AVIATION...ERI/LKB
MARINE...AJZ/JDM
TIDES/COASTAL FLOODING...AKQ
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
653 PM CDT Mon Oct 7 2019
.DISCUSSION...Updated for latest aviation discussion below.
&&
.AVIATION...As of 23z/6PM CT, a weak cold front was draped right
over the Rio Grande Valley, in the vicinity of MFE and HRL. Ahead
of the front, northeast winds have been occasionally gusty between
20 and 25 knots at each TAF terminal. Anticipate winds to
decrease once the cold front is able to push through, sometime
between 01-02z. VFR conditions are expected to prevail over the
next 24 hours, but isolated showers and thunderstorms are still
possible behind the front, especially at HRL and BRO through at
least sunrise Tuesday morning. Based on the latest HRRR run,
included tempo groups for each TAF site between midnight and
sunrise for a stray shower/thunderstorm or two...although
confidence is low. Convection may briefly produce MVFR or IFR
conditions if they occur over the runways. Cannot completely rule
out a shower or thunderstorm or VCSH/VCTS at HRL and BRO during
the afternoon Tuesday, but chances are low enough to not include
in TAFs.
Overall forecast confidence: Low-moderate.
&&
.PREV DISCUSSION... /issued 355 PM CDT Mon Oct 7 2019/
SHORT TERM (Now through Tuesday Night): "Cold" front is tough to
identify, since surface troughing roughly along the coast had
already turned winds northerly, not to mention the minimal
temperature contrast across the boundary. Weak radar echoes and
surface observations suggest it may be sagging into northern
Starr/Hidalgo counties at this time. At any rate, as mentioned in
update AFD earlier, had to drop PoP`s by 10% for the remainder of
the afternoon. With the slower/weaker progression of the front,
temps have already reached 91F at BRO and 97F at MFE.
Overnight, still expecting more comfortable temperatures (though
still a few degrees above normal) as lower dewpoints filter in
behind the front. Mentionable precip chances will generally be
limited to the mid/Lower Valley and areas east of I-69E/Hwy. 77 as
better moisture remains near the boundary, which stalls offshore and
perhaps develops a very weak coastal trough. Some CAM guidance also
suggesting that clusters of thunderstorms will develop over the Gulf
waters and possibly drift toward the coast later tonight.
Rain chances of the isolated to widely scattered variety remain in
play for Tuesday along the coast, but the rest of the area should be
dry, with NW flow in the upper troposphere taking hold and a lower-
level mesoscale high settling overhead. We should be a few degrees
cooler than today, but had to increase inherited temps a bit. Upper
80s to lower 90s will be common.
Surface winds veer back to SE Tuesday night as high pressure center
to our north migrates east. With column moisture on the decline and
little in the way of forcing, will finally drop any mention of
precip. With onshore flow re-establishing, morning lows on
Wednesday are expected to be in the lower 70s across the populated
RGV...perhaps mid-70s in Brownsville.
Opted not to re-issue the Coastal Flood Statement which expired this
morning. Water levels are still running about 1 ft. above
astronomical predictions, but with the front eventually backing
winds across the northern Gulf, the easterly fetch should finally be
disrupted. Will let evening shift have a last look leading up to
high tide at 2:53 AM.
LONG TERM (Wednesday through Monday): Mid-range forecast models
are in agreement that a subtropical 500mb ridge will begin to
build over Southern Texas, Northern Mexico, and the Western Gulf
of Mexico on Wednesday. Meanwhile, a significant and deepening
mid-level trough will eject out of the Pacific Northwest on Wednesday
and into the Rockies by Thursday afternoon. At the surface,
southeast flow will promote a warming trend across Deep South
Texas Wednesday, Thursday, and likely into Friday. Subsidence
from the mid-level ridge should keep things mostly dry through
Thursday night. Confidence is high that afternoon high
temperatures will be in the mid-upper 90s across the CWA, with
lower 100s possible west of US 281/I69C, on Wednesday and
Thursday.
Forecast confidence begins to lower by Friday, as long-range
model solutions diverge. A relatively robust cold front will be
pushing through the CWA sometime between Friday evening and early
Saturday morning. However, the exact timing of the fropa is still
up in the air at this time. The GFS solution continues to be the
faster solution, which bring the cold front through by late
afternoon or early evening on Friday. Meanwhile, the ECMWF has the
cold front coming through late Friday night, into early Saturday
morning. Will continue to lean more towards the slower ECMWF
solution due to the strength of the ridging aloft, which may slow
the front down as it approaches Deep South Texas.
With the timing of the front still in question, it will ultimately
affect the temperature forecast on Friday, into Saturday morning.
If the ECWMF solution does verify, it may cause a heat spike due
to compression ahead of the cold front. Afternoon high temperatures
would warm up into the upper 90s to lower 100s across much of the
area. For now, went ahead and ran a blend of the two model
solutions, but this will have to be monitored over the next couple
of days. Behind the front, temperatures will be much cooler, with
highs mainly in the low-mid 70s on Saturday and lows in the upper 50s
to mid 60s Saturday and Sunday mornings. A warming trend will
begin on Sunday as surface winds gradually turn back out of the
east and eventually southeast by late Sunday night. As far as
precipitation goes, models are in agreement that there will be
sufficient moisture ahead and along the front to cause scattered
showers and thunderstorms across the region Friday into Saturday.
Conditions are expected to dry west to east through the day on
Saturday. However, kept PoPs along the coast and offshore through
Monday as coastal troughing tries to set up.
Overall confidence in the longer range forecast continues to be
below average this afternoon due to the various model differences
showing up later this week.
MARINE (Now through Tuesday Night): Front appears to have passed
Buoy 42020 between 1-1:30 PM, with brief gusts to 25KT reported.
Northerly winds have since settled back into the 15-20KT range, so
will keep Small Craft Exercise Caution (SCEC) wording going for the
20-60nm Gulf waters. Winds around the Laguna Madre have come up to
around 15 knots, so will have to watch for SCEC conditions there as
well. Overall, models have trended weaker with winds behind the
front. Moderate seas of 4-5 ft. should hold through the day Tuesday
before subsiding to around 3 ft. by daybreak Wednesday as lighter
onshore flow returns.
Wednesday through Saturday: The low level flow will generally be
from the southeast from Wednesday and Thursday as the post
frontal surface ridging shifts eastwards and weakens somewhat.
Small Craft Exercise Caution conditions possible Wednesday and
Thursday afternoon and evening, especially on the Gulf waters.
The PGF will then strengthen significantly Friday evening as the
the next strong cold front moves through the region. SCA
conditions are expected for both the Bay and Gulf waters starting
late Friday through Saturday.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
This product is also available on the web at:
HTTP://WEATHER.GOV/RGV
Aviation...67-Mejia
Area Forecast Discussion
National Weather Service Hastings NE
640 PM CDT Mon Oct 7 2019
...Aviation Update...
.SHORT TERM...(This evening through Tuesday)
Issued at 222 PM CDT Mon Oct 7 2019
Aloft: Low-amplitude NW flow was over NEB/KS at 19Z per RAP
tropopause analyses and aircraft wind data. A trof extended from
Ern Can to TX. A modest shrtwv rdg extended from Cntrl Can to
UT/CO. A small/weak shrtwv trof was along the CA/NV border. The
shrtwv rdg will crest over the Cntrl Plns tonight while the CA/NV
trof conts moving E. The flow over the CONUS will remain low-
amplitude thru tomorrow with winds shifting to WSW over NEB/KS.
The small/weak trof will cross CO tomorrow and will be moving into
NEB/KS by 00Z.
Surface: 1026 mb high pres was over KS/OK. Widespread downslope
flow was occurring to its N to the lee of the Rckys. The high will
head into the GtLks tonight and New Eng tomorrow. Downslope/
return flow will cont over NEB/KS thru then. Meanwhile...an
unseasonably strong cold front will sink out of SW Canada into the
Pac NW.
Tonight: Mostly clr. Not as cold as winds will remain up. Lows in
the 40s.
Tue: Sunny and very comfortable...but brzy. S winds will gust
25-35 mph. Near normal temps with highs low-mid 70s. Incrsg
cirroform clds in the afternoon ahead of the aprchg trof.
.LONG TERM...(Tuesday night through Monday)
Issued at 222 PM CDT Mon Oct 7 2019
Aloft: An unusually deep trof (-2 SD) was over Wrn Can. The flow
over the CONUS will become highly-amplified this wk as this trof
sinks into the Wrn USA and deepens...along with a shortening
wavelength. The flow will become SW over NEB/KS Wed-Thu as the
trof gradually drifts E. Most mdl runs and the EC ensemble mean
suggest a low will form within the trof and intensify as it heads
NE acrs the Dakota`s Fri. The -2.5 SD trof will cross the CWA in
its wake Fri with cyclonic NW flow cont into Sat as the low slows
over MN. Mdl spread increases Sun-Mon...but it appears cyclonic NW
flow will remain over the CWA Sat-Sun. There will probably be a
wk shrtwv trof moving thru the Wrn USA...with a modest rdg
preceding it. Not sure how this will play out for next Mon.
Surface: With the incrsg amplitude/shortening wavelength of the
upr trof...the strong cold front is now fcst to cross the CWA
Thu... slower than expected earlier. So the CWA will remain in the
warm sector thru Wed night. Strong 1036 mb high pres over the Nrn
Rckys will begin bldg in behind the front Thu. Deepening low pres
will move up the front and occlude over the Nrn Plns Fri. Mdl
diffs dvlp Sat. The Wrn USA high will probably emerge into the Srn
Plns...but will the thermal trof lift out and return flow dvlp?
Or will the large circulation with the departed (and probably cut-
off) low still influence the wx here? Too soon to determine.
Temps: Wed the NAM/GFS suggest low stratus could dvlp around
sunrise and linger thru much of the day for portions of the CWA.
This will suppress temps if it doesn`t break apart. So parts of
the CWA may not be as warm as we`ve indicated. Temps should
average near normal. Thu highs will occur at midnight. Temps will
fall...espcly in the AM...then hold steady or fall slowly in the
afternoon. Fri unseasonably cold. Much of S-cntrl NEB will only
reach the 30s! Sat some recovery into the 40s/50s...but still much
chillier than normal. Sun-Mon are uncertain. Probably still
cooler than normal.
Confidence is high that widespread/killing freezes will occur Fri
and Sat mornings. Lows in the 20s to low 30s expected. A Freeze
Watch/Warning will be required.
It is psbl Valley/Greeley counties may see 4 consecutive mornings
with subfrzg temps Fri-Mon! See 00Z and 12Z MEX guidance.
Precip: There is a slgt chance a cpl shwrs or tstms could skirt
the far SE fringe of the CWA toward dawn Wed thru mid-morning.
Most of the activity should remain over Cntrl/Ern KS. A few more
isolated shwrs/tstms are psbl Wed night into Thu AM along and
ahead of the cold front. Believe our POPs are too high over
S-cntrl NEB (60-70% N of I-80). Would feel more comfortable with
30-40%.
There could be a little light rain Thu night into Fri AM as the
potent upr trof moves thru. Temp profiles will gradually become
cold enough from NW-SE to change the rain over to wet snow...if
precip is occurring. Not all areas will see rain/snow. The mdl
consensus is unanimous that the upr low will track W of the CWA.
That means little or no snow accum.
Wind: As is typical for these situations...N winds will be
howling 20-30 mph Thu and Fri...with gusts of 35-45 mph.
Will issue a SPS to raise awareness of the upcoming end to the
growing season.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Tuesday)
Issued at 628 PM CDT Mon Oct 7 2019
VFR conditions are expected with dry weather throughout the TAF
valid period. The primary aviation concern centers around strong
low level wind shear primarily after midnight through around 10 AM
CDT Tuesday.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Kelley
LONG TERM...Kelley
AVIATION...Wesely
Area Forecast Discussion
National Weather Service Goodland KS
753 PM MDT Mon Oct 7 2019
.UPDATE...
Issued at 750 PM MDT Mon Oct 7 2019
Forecast has been updated to show the potential for patchy frost
Tuesday morning mainly in low-lying areas in east-central
Colorado. Temperatures are expected to get as low as the upper 30s
and could approach around 36 or 37 degrees in some spots. That
might be cold enough to produce patchy frost, although forecaster
confidence is low in how widespread that coverage of frost will
be.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 131 PM MDT Mon Oct 7 2019
Water vapor imagery and 500mb RAP analysis show the region under
northwest flow on the backside of an exiting upper trough today. To
the southwest, high pressure is centered over Baja California with
ridging over the Desert Southwest. Winds turned to the south early
this afternoon as a lee trough deepened along the Rockies. At 1 PM
MDT, winds were gusting around 25 to 30 mph with temperatures in the
upper 60s to low 70s.
Winds relax some through the overnight hours as temperatures fall
into the upper 30s to mid 40s. Clear skies are expected.
A strong upper trough digs into the Pacific Northwest on Tuesday and
flow aloft of the region shifts to southwesterly. The surface trough
east of the Rockies migrates further into the region, pushing south
winds of 10 to 20 mph to the eastern half of the area. Fortunately,
light winds will be to the west where relative humidity values are
forecast to fall between 10 and 20 percent in the afternoon. This
should mitigate fire weather concerns. High temperatures will be in
the upper 70s to low 80s before falling into the 40s and low 50s
Tuesday night. Could see an increase in cloud cover when a
disturbance moves across central Kansas. There will be a potential
for some fog late Tuesday night/early Wednesday morning when
moisture pools along a boundary in the area.
.LONG TERM...(Wednesday through Monday)
Issued at 156 PM MDT Mon Oct 7 2019
During this extended period there is a good chance for the first
snowfall of the Fall/Winter season.
Models are showing a deepening upper-level trough moving across the
Rockies and into the High Plains through Friday Morning. This upper-
level trough will aid in the development of a surface low pressure
system coming off the Front Range and over the southern part of our
local area. As this system develops and moves towards the east-
northeast, a cold airmass is anticipate to move in behind it; along
with precipitation impacts from Wednesday night into the early hours
of Friday morning. Precipitation will move from west to east across
the Central High Plains and start out as rain before turning into
snow. By Thursday evening expect snow across the region.
The National Blended Model (NBM) has snow accumulation ranging from
up to 3 inches in the Yuma, Colorado area to less than a half of an
inch in the Colby, Kansas area. However, there is a lot of
uncertainty at this time with the accumulation amounts. We will keep
an eye on this and update during the overnight forecast run.
After the system moves out of the region dry conditions will
return; however, this cold airmass will bring below normal
temperatures to the region during the later part of the week and over
the weekend. High temperatures are expected to reach only into the
upper 30s to middle 40s on Thursday and Friday before reaching into
the 60s Saturday and Sunday. Overnight lows will drop into a range
of upper teens to middle 20s Thursday night followed by the middle
30s over the weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 524 PM MDT Mon Oct 7 2019
High pressure over the region will provide VFR conditions for
both taf sites during the forecast period.
Winds...S 15-30kts thru 07z-11z Tuesday...then SSE around 10kts.
LLWS for KMCK 07z Tuesday onward 210@35kts.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...PATTON
SHORT TERM...JBH
LONG TERM...BW
AVIATION...JN
Area Forecast Discussion
National Weather Service Lincoln IL
832 PM CDT Mon Oct 7 2019
.SYNOPSIS...
Issued at 203 PM CDT Mon Oct 7 2019
High pressure ridging into the midwest from Ontario will provide
the region fall-like weather through mid-week. A cold front will
approach Illinois Thursday bringing our next chance of rain.
&&
.UPDATE...
Issued at 832 PM CDT Mon Oct 7 2019
Winds have become calm across central Illinois this
evening...allowing 01z/8pm temperatures to rapidly fall into the
lower to middle 50s. Excellent radiational cooling will continue
for the remainder of the night as overnight lows bottom out in the
lower to middle 40s. Other than some minor hourly temp/dewpoint
tweaks, current forecast is right on track and requires no major
updates.
&&
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 203 PM CDT Mon Oct 7 2019
High pressure will dominate Illinois through 24 hours with light
and variable winds and seasonal temperatures. There remains a
chance of some patchy fog around sunrise near and northwest of the
Illinois River as indicated by the latest RAP and 3km NAM.
However, forecast soundings indicate that any moisture will be
extremely shallow and will likely be confined to river valleys.
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 203 PM CDT Mon Oct 7 2019
A gradual warming trend is expected through Thursday as weak
ridging develops aloft in response to a digging upper low over the
mountain west. Temps at 850 mb climb to near 15c by late
afternoon Thursday as a prolonged period of warm advection
develops. This will enable temps to reach to near 80 southeast of
the Illinois River. temperatures should be a little cooler
northwest of the river where clouds and isolated showers may keep
the temps down a bit Thursday.
Models are in reasonable agreement with strong stacked system
pulling out of the plains and into the western Great lakes for the
end of the week. Slight differences in the surface and upper-low
track may lead to some minor timing differences, but overall
agreement is unusually strong for such a powerful system. The main
thrust of the precip will likely push into Illinois Thursday
Night ahead of a strong cold front associated with the system. The
system`s progression will be slow as the main energy moves
northeast up the Mississippi Valley which will lead to a period
of occasional showers and thunderstorms Thursday Night and
Friday. The best chances of significant convection will be Friday
afternoon as the front pushes across Illinois. Although
instability is somewhat limited, shear and dynamics should be
sufficient for thunderstorms. Will need to monitor the situation
closely this week to see how the system develops. The trend has
been slowing with each model suite and if that continues it may be
more of a nocturnal threat Friday evening/night.
Cold temps will advect in on strong west to northwest winds in
the wake of the front. Temps at 850 mb plunge 15-20c from Thursday
afternoon into Friday Night. The deterministic GFS actually drops
down to around -7c at 850 mb, but looking at the NAEFS the
deterministic GFS is definitely an outlier on the cold side of the
solution envelope. The MEX guidance values near freezing by
Saturday Morning (which are based on the GFS) are likely a little
on the cold side.
Once the front moves through, skies should clear for most of the
weekend with temperatures below seasonal normals for early
October. Winds and clouds should prevent frost Saturday Morning,
but we will need to keep an eye on Sunday and Monday mornings for
the potential for patchy frost in protected locations.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 631 PM CDT Mon Oct 7 2019
VFR conditions will prevail through the entire 00z TAF period as
high pressure dominates the weather. Skies will be clear and
light/variable winds tonight will gradually become S/SE on
Tuesday as the high shifts into the Ohio River Valley.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barnes
SYNOPSIS...Barker
SHORT TERM...Barker
LONG TERM...Barker
AVIATION...Barnes
Area Forecast Discussion
National Weather Service Melbourne FL
917 PM EDT Mon Oct 7 2019
.UPDATE...
Broad area of low pressure/inverted trough located across south
Florida along with high moisture gave almost all of east central
Florida measurable rainfall today along with some isolated storms.
Latest RAP depiction of MSLP places the trough axis roughly from
Lake Okeechobee extending through the Treasure Coast and to the
ENE over the Atlantic. This places areas from Vero Beach northward
on the ascending side of the trough, and some PVA aloft is
providing additional lift. Radar imagery is supporting this well
with high coverage of showers and isolated storms across Brevard
into Osceola county and over the adjacent Atlantic. This should
continue across this area with some of this activity possibly
pushing northward into eastern Orange and Volusia through the
early overnight before high res models show most of the activity
transitioning more offshore. Scattered showers will continue
across the interior, but coverage is expected to decrease through
the night as well. Main update this evening is a slight lowering
of rain chances for the Treasure Coast and across the interior.
&&
.AVIATION...
Highest coverage of showers and isolated storms will be in the MLB
and TIX corridor through the early overnight hours where TEMPO
MVFR/IFR restrictions are in place. Showers and storms expected to
transition more offshore overnight, but with the high moisture and
broad low pressure nearby VCSH will remain in all TAFs. High rain
chances again Tuesday so TAFs continue to carry at least VCSH
through the period.
&&
.MARINE...
Tonight...No changes to headlines. Solid small craft advisory
conditions still in place over the local Atlantic waters based on
latest observations.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 74 85 74 83 / 60 60 40 70
MCO 73 86 73 86 / 50 60 40 80
MLB 76 86 73 85 / 70 70 40 70
VRB 74 86 72 86 / 60 70 50 70
LEE 74 87 72 85 / 60 60 30 70
SFB 73 86 73 85 / 50 60 40 70
ORL 73 86 74 85 / 50 60 40 80
FPR 74 86 71 86 / 50 70 50 70
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Small Craft Advisory until 4 AM EDT Tuesday for Flagler Beach to
Volusia-Brevard County Line 0-20 nm-Sebastian Inlet to
Jupiter Inlet 0-20 nm-Volusia-Brevard County Line to
Sebastian Inlet 0-20 nm.
Small Craft Advisory until 4 PM EDT Tuesday for Flagler Beach to
Volusia-Brevard County Line 20-60 nm-Sebastian Inlet to
Jupiter Inlet 20-60 nm-Volusia-Brevard County Line to
Sebastian Inlet 20-60 nm.
&&
$$
Combs/Pendergrast
Area Forecast Discussion
National Weather Service Marquette MI
739 PM EDT Mon Oct 7 2019
.SHORT TERM...(This evening through Tuesday)
Issued at 347 PM EDT MON OCT 7 2019
Water vapor imagery and RAP analysis show that the trof that was
over the western Great Lakes early this morning is now shifting e of
the area. Last of the lake enhanced -shra associated with the trof
ended over the far eastern fcst area a little after noon today.
Otherwise, there was an expansion of cu/stratocu over much of the
fcst area late morning/early aftn under 850mb thermal trof. Those
clouds have been steadily dissipating from w to e over the last
couple of hrs. It`s been another breezy day, but winds have not been
as strong as yesterday. Winds today have been mostly gusting to 20-
30mph, but up to 35mph or so on the Keweenaw.
A dry/mild period of weather is on the way for at least the next
couple of days, but it will be a cool night tonight as sfc high pres
ridge moves across the area this evening and then drifts e
overnight. A dry air mass with precipitable water down around 1/3rd
of an inch (50-60pct of normal) will aid the cooling potential.
Favored the lower side of guidance across the interior central and e
which will be closer to the departing high pres ridge overnight.
Expect min temps down into the low/mid 30s in that area. Traditional
cold spots may slip blo 30F. There will be frost, but no headlines
with this fcst as frost/freeze headline issuance has ended for the
season. Southerly winds will begin stirring w and across the n
overnight, keeping temps mostly in the lower 40s.
Tue will be breezy and warmer under s to sw winds btwn high pres
ridging from southern Quebec to TX and a low pres trof extending
from Manitoba to MT. Based on mixing heights on fcst soundings, wind
gusts of 20-30mph should be common late morning/aftn. Some gusts up
to 35mph will be possible w. Expect abundant sunshine, but there
will be some thin, high clouds streaming into at least the w during
aftn. High temps will be mostly in the mid to upper 60s.
.LONG TERM...(Tuesday night through Monday)
Issued at 424 PM EDT MON OCT 7 2019
We`re certainly in for a ride this week weather wise as temperatures
soar 5 to 10 degrees above normal for this time of year throughout
the week, and them plummet to below normal for the upcoming weekend,
as a developing low over the Upper Mississippi Valley deepens,
weakens and eventually stalls out over the region. With the
fluctuating temperatures will come increased chances for
precipitation later this week, especially Thursday night into Friday
when widespread rain is expected to lift across the area. It is
still possible that we could see the first snowflakes of the season
out west, mainly on Saturday/Sunday. However, the best chance for
accumulating snow looks to remain west of the area. While we may not
see much in the way of snow with the system, given how wet it has
been as of late and the colder temperatures expected this weekend
anyone with outdoor recreational plans should certainly plan and
prepare for the colder weather!
Through the middle/end of the work week a weak rex block setting up
over the Northeast looks to continue to slow the arrival of a
digging trough over the Central CONUS. As a stout baroclinic zone
develops from the southern Plains up into the Upper Mississippi
Valley, we will find ourselves on the warm side, with steady warm
air advection pumping into the region. This will favor as mentioned
above, above-normal temperatures for this time of year. Cloud cover
doesn`t look to be a major issue for temperatures, but overall
looking at temperatures in the 60s through at least Thursday.
Locations that see downsloping impacts from breezy southerly winds
on a daily basis may see locally warmer temperatures compared to
elsewhere across the Upper Peninsula. Otherwise, through Thursday we
look to remain dry with breezy winds, both during the day and
overnight hours due to the enhanced pressure gradient expected to
setup across the region.
Early Friday morning into Saturday, the longwave trough slowly
digging southeast across the central CONUS will take on a negative
tilt as it lifts across the Upper Mississippi Valley. This will
bring one last surge of strong warm air advection across the region
and the arrival of much deeper moisture. Initially Friday morning,
precipitation looks to remain on the lighter side of things;
however, as an axis of impressive PWATs for this time of year lifts
north along the axis of stronger warm air advection and moisture
transport moisture, expect rain to pick up in intensity as we
progress through the day Friday and into Saturday morning. Given the
45+ knot LLJ and overall increase in large-scale lift, as the wave
takes on a negative tilt during this time period, it certainly looks
like the overlapping of lift and impressive, deeper moisture will
result in moderate to at times heavy rain. Have continued to leave
thunder out at this time, given the instability still doesn`t look
like it will get this far north. Some training of heavier rain is
possible, especially across parts of the central and east. As the
system does deepen to our west during this time period, it does
appear that we will see windy conditions develop as well.
Depending on the wind direction/speed over the Great Lakes, we
could run into some lakeshore flooding concerns due to the high
water levels and stronger winds. Something to keep an eye one!
While there is some disagreement among the medium range guidance
with the track of the system as it becomes vertically stacked and
weakens Saturday into early next week, it certainly will be a cold
and cloudy weekend. As the main axis of widespread rain looks to
shift east of the region by mid-day Saturday, we could see some
light wrap around snow move into western parts of Upper Michigan.
The rest of Upper Michigan looks to be dry slotted for some time as
the drier, cooler air wraps into the region. Given the southwest
flow expected on Saturday, it doesn`t look like there will be a lake
component potential from Lake Superior until the stacked low moves
east over Lake Superior later in the weekend/early next week.
However, off of Lake Michigan could see some lake effect rain
showers develop due to the colder air lifting across the lake
throughout the weekend.
Once the low does start to shift east over Lake Superior, and
eventually into Ontario, later in the weekend/early next week,
lingering cold air aloft will keep chance for precipitation in the
forecast. It remains questionable whether it will be cold enough or
deep enough moisture to support any lake-driven snow. However,
certainly should be some lingering rain showers around, especially
in the west-northwest wind belts as the main 850mb low pulls
northeast of the area.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 737 PM EDT MON OCT 7 2019
Under a dry air mass, VFR conditions will prevail at KIWD/KCMX/KSAW
thru this fcst period. Gusty sw to s winds will develop late
Tue morning/aftn. Gusts to 20-25kt should be common in the aftn.
&&
.MARINE..
As high pressure shifts over the Northeast through mid-week, winds
will become predominately southerly between 15 and 25 knots. The
strongest winds are expected over the north and east parts of the
lake, where fetch over the lake will be maximized. Thursday into
Friday, winds back and become more southeasterly between 15 and 25
knots, ahead of a developing low pressure system over over the Upper
Mississippi Valley. Again, the strongest winds are during this time
period are expected over the north and eastern parts of the lake.
By mid-day Friday, the developing low will continue to lift north
and deepen as it moves over the Arrowhead of Minnesota and far
western parts of Lake Superior. This will allow winds over the north
and eastern parts of the lake to accelerate Friday into Saturday, to
speeds between 20 and 30 knots. Friday afternoon into Saturday
morning, southeast gales of 35 to 40 knots continue to look possible
over the northern and eastern parts of the lake. Looking ahead to
the middle/end of the weekend, overall confidence is low in the wind
forecast that far out as models really struggle to paint a
consistent track of the surface low and how strong it will be.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...Ritzman
AVIATION...Voss
MARINE...Ritzman