Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/18/18
Area Forecast Discussion
National Weather Service Charleston SC
936 PM EDT Wed Oct 17 2018
.SYNOPSIS...
A cold front will push south of the region tonight. Cooler high
pressure will build over the region Thursday and Friday before
shifting offshore Saturday. A stronger cold front will advance
through the area Saturday night, followed by cool high pressure
through the middle of next week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
The cold front was located roughly along a Tybee Island, GA to
Glennville, GA line at 18/0130z and moving south. The boundary
is on target to push south of McIntosh County early Thursday
morning as cool, high pressure wedges south into the region
behind it. Any isolated shower activity associate with the front
should remain over the Georgia coastal waters over the next few
hours within the pre-frontal warm sector.
Expect a fairly widespread 3.5-4.0 kft stratocumulus deck to
develop by mid-late evening in response to increasing isentropic
assent, mainly along the 305K surface. Condensation pressure
deficits (CPDs) along this surface are forecast to remain fairly
high (>20 hPa), so most of the lift should go to thickening
cloud development instead of shower production. Could see a
sprinkle or two develop over parts of the Charleston Tri-County
area closer to midnight where CPDs drop closer to 10 hPa for a
few hours, but think the risk for measurable precipitation is
just too low to mention as the mid- levels continue to dry out.
Modest post-frontal cold air advection will help drive overnight
lows from the mid 50s across far northern parts of Dorchester
and Berkeley Counties away the Santee-Cooper lakes to the lower
70s along the Georgia coast where a developing onshore will
help moderate temperatures quite a bit.
For the late evening update:
* Made minor adjustments to wind and wind speeds per latest RAP
and H3R output.
* Made minor adjustments to dewpoints based upstream trends.
The rest of the forecast is on track.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
Thursday: High pressure will provide much cooler conditions as
compared with recent days. High temps Thursday will range from the
upper 60s/lower 70s north to the lower/mid 70s south. Thursday
night, inland low temperatures will range from the upper 40s/lower
50s inland/north to the mid 50s.lower 60s south. NE winds will
maintain temperatures in the lower/mid 60s on the beaches. As the
high pressure shifts into the Atlantic and a coastal trough
develops, a few showers could push onshore into GA coastal counties
late.
Friday: Expect temps a bit warmer than those of Thursday.
Temperatures will be close to normal for mid October, ranging from
the lower/mid 70s north to the mid/upper 70s south. Onshore flow
interacting with a coastal trough could support a few showers,
especially across central/southern coastal counties.
Friday night: Low-level flow will turn toward the south/southwest
ahead of an approaching cold front. This will hold low temps in the
lower/mid 60s inland and around 70F at the coast. Also, guidance
suggests that moisture transport will intensify along the coast and
adjacent coastal waters, supporting at least isolated/scattered
showers. Accordingly, at least slight chance/chance PoPs are in
order along the coast and adjacent coastal waters, especially
overnight.
Saturday: A strong cold front will approach the region. Ahead of the
front, early showers are expected to push offshore, then
showers/thunderstorms should push into the region during the
afternoon. There remains some uncertainty regarding timing/coverage
of prefrontal convection, so afternoon PoPs are capped at 40-50
percent. Meanwhile, outside any showers/thunderstorms, WSW winds and
compressional heating will help push temps into the lower/mid 80s.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
The cold front and associated showers are expected to cross the
region Saturday night. Then, high pressure will provide below-normal
temperatures Sunday through early next week, followed by a trend
toward near normal temps midweek. As the high shifts offshore,
coastal troughing could support occasional showers along the coast
next week.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
VFR. Gusty winds will develop later this evening and persist
into Thursday morning before diminishing.
Extended Aviation Outlook: Mainly VFR. Flight restrictions are
possible in showers as a cold front crosses the region Saturday into
Saturday night.
&&
.MARINE...
Tonight: Post-frontal cold air advection and the associated
isallobaric rises will support winds increasing to 20-25 kt
with gusts to 30 for much of the waters off the South Carolina
coast and 15-20 kt with gusts to 25 kt for the Georgia waters
through daybreak. Small Craft Advisories for all coastal legs
look well placed and were not changed, although the beginning
times may be a few hours too fast. Seas will build in the
strengthening northeast flow, peaking 4-6 ft off the Charleston
County coast to 2-4 ft off the Georgia coast by daybreak. For
Charleston Harbor, winds look a bit too marginal for a Small
Craft Advisory with winds peaking 15-20 kt. Could see a few
gusts near 25 kt near the harbor entrance, but these should
remain fairly infrequent and not enough to justify an advisory
at this time.
Thursday through Monday night: High pressure will produce elevated
northeast winds and elevated seas Thursday into Friday, justifying
ongoing Small Craft Advisories outside Charleston Harbor. As high
pressure shifts into the Atlantic and a strong cold front approaches
the region, winds will turn toward the S/SW Friday night and toward
the W/SW Saturday. Winds/seas should remain below SCA thresholds
through this period. Then, another cold front will cross the waters
Saturday night, followed by high pressure and strong cold air
advection. Winds will shift to the north/northwest through Sunday
and will veer toward the northwest Sunday night. Elevated winds/seas
will likely reach SCA levels in most areas.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory from 2 AM to 11 PM EDT Thursday for
AMZ350-352.
Small Craft Advisory from 5 AM Thursday to midnight EDT Friday
night for AMZ374.
Small Craft Advisory from 5 AM Thursday to 5 AM EDT Friday for
AMZ354.
&&
$$
Area Forecast Discussion
National Weather Service Hastings NE
645 PM CDT Wed Oct 17 2018
.SHORT TERM...(This evening through Thursday)
Issued at 239 PM CDT Wed Oct 17 2018
Aloft: RAP model tropopause analyses show split flow over the
CONUS with a ridge over a cut-off low in the W and confluent flow
downstream over the E. The cut-off low has induced a shortwave
ridge over the Cntrl Plns. This ridge will drift E of the rgn
tomorrow as the cut-off low weakens and opens up into a trof that
is fcst to extend from ND-WY-UT by 00Z/Fri. This will result in
the flow becoming SW.
Surface: Abnormally strong 1033 mb high pres was over Neb/KS. A
continental polar air mass covered most of the Cntrl/Ern USA. The
high will migrate E into the Midwest tonight and in the OH Vly
tomorrow. SW flow will strength as a result.
Tonight: Clear to start but incrsg mid-lvl clds from the SW as
the ridge axis edges E. Used cross sections to time the leading
edge of the clds.
Lows primarily 40-43F except colder in the Loup Rvr Vlys.
Thu: Partly-mostly cldy as mid-lvl clds cont to advance across
the entire CWA. Highs should still be in the 60s...but coolest
(around 60F) S and W of the Tri-Cities. Some sprinkles will be
possible mainly after noon. There might even be enough to wet the
roads S of KS Hwy 24.
Becoming brzy. By midday SW winds will be 15-20 kt with G25-30
kt.
.LONG TERM...(Thursday night through Wednesday)
Issued at 239 PM CDT Wed Oct 17 2018
Aloft: The current longwave pattern (described above) will remain
in place...but will show signs of progression and possibly
deamplification mid-late next wk. The shortwave trof just NW of
the CWA Thu eve will cross the rgn Fri. NW flow will prevail over
the Plns Sat-Mon with a shortwave ridge moving in late Mon. Spread
among the last 2 runs of global models increases next Tue-Wed
regarding the trof that comes out of the Desert SW into the
Plns...but the 00Z EC ensemble mean looks similar. So it appears
the ridge will move E Tue night with the trof moving in Wed.
Surface: The next Canadian cool front will be dipping into the
Nrn Plns Thu night. It will sweep thru here Fri with little more
than a wind shift and an increase in winds. Strong but quick-
moving 1030+ high pres will drop out of Canada into the Plns Fri
night into Sat. The next low will advance thru cntrl Canada Sun
and this will drive a warm front thru here. The associated cool
front will quickly move thru behind it Mon. A big Canadian high
will then build in as it slides into the GtLks Tue-Wed.
Temps: Overall should average near normal. Near 70 Fri which is
currently looking like the warmest day of the next 7. A brief
intrusion of cool Sat (50s)...back to the 60s Sun-Mon...then down
to the 50s again Tue-Wed.
Precip: Some sprinkles could linger into Thu eve. Otherwise dry
until next Tue night or Wed. That system that will come out of the
Desert SW is not looking very wet. The +RA will be over the Srn
Plns with lighter rain possible up here.
Potentially hazardous wx: None.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday)
Issued at 635 PM CDT Wed Oct 17 2018
Surface high pressure will continue to slide to the southeast as
an upper level disturbance across the southwest lifts
northeastward towards the plains. A tightening pressure gradient
is anticipated ahead of this system...with wind gusts of 25 to 30
mph expected tomorrow afternoon. Conditions overall will remain
VFR...although increasing high cloud are expected overnight...with
CIGS lowering to around 12KFT tomorrow afternoon.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Kelley
LONG TERM...Kelley
AVIATION...Rossi
Area Forecast Discussion
National Weather Service Goodland KS
1000 PM MDT Wed Oct 17 2018
.SHORT TERM...(This evening through Thursday)
Issued at 327 PM MDT Wed Oct 17 2018
Latest upper air analysis shows the closed low over the Four Corners
Region. Rounding the closed low was a plume of higher water vapor
concentration extending north to the KS/OK border. Isolated showers
were moving north in the higher moisture plume. Northeast of the
closed low a long wave trough continued over the Eastern CONUS.
Tonight the showers will continue to move north toward the forecast
area. Most of the stronger lift will be south of the forecast area.
However isolated showers may move into the forecast area after
midnight.
Thursday morning the plume of moisture and showers will continue to
drift north over Kansas. The best isentropic lift will occur during
the latter half of the morning, into the early afternoon before the
drier air pushes the showers east of the forecast area. Confidence
for any rain development is on the low side due to the somewhat
scattered lift moving over the forecast area.
A low level jet will develop over the forecast area. Winds from
this feature will mix down to the ground, causing wind gusts to
range from 30-40 MPH.
.LONG TERM...(Thursday night through Wednesday)
Issued at 327 PM MDT Wed Oct 17 2018
Most of this period will be dry except for the next chance for rain
mid week next week.
A couple weak cold fronts will move through the forecast area Friday
through Monday as the closed low over the Desert Southwest becomes
absorbed in the long wave trough. These frontal passages will cause
the highs to vary each day by as much as 10 degrees. Due to the
subsidence and drier air with the trough axis overhead, am not
expecting any clouds to form during this time despite the frontal
passages.
Toward mid week an upper level short wave ridge will move over the
Plains. Behind it a short wave trough will move through, giving the
forecast area a chance for rainfall.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1000 PM MDT Wed Oct 17 2018
A weather disturbance with good moisture in the 850-500mb layer
originating along the Texas/New Mexico border late this evening is
forecast to forecast to move northeast reaching the KGLD terminal
in the 18z-21z timeframe and the KMCK terminal in the 20z-23z
timeframe producing a few rain showers over/near the terminals.
After 00z the weather disturbance moves away from the terminals.
The NAM and 00z HRRR do show sub vfr stratus developing around the
KGLD terminal after about 02z so have added that to the forecast.
South winds below 11kts expected at both terminals through about
13z before quickly increasing from the south at KGLD by 14z and
KMCK around 17z. Peak gusts around 35kts possible. Winds subside
and fall below 12kts in the 01z (KMCK) to 05z (KGLD) timeframe.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JTL
LONG TERM...JTL
AVIATION...99
Area Forecast Discussion
National Weather Service Louisville KY
910 PM EDT Wed Oct 17 2018
.Forecast Update...
Issued at 910 PM EDT Wed Oct 17 2018
Upper disturbance over the Red River Valley has spread a respectable
cirrus shield ahead of it into the Ohio Valley. This maintains
plenty of bust potential in our min temp forecast overnight, and
therefore the Frost Advisory that is already flying.
None of the synoptic models seem to handle these clouds well, and
much of the hi-res guidance is also struggling. Only the HRRR seems
to be on board, and it actually has skies clearing out again just
before daybreak.
Will not change the min temp forecast, but have adjusted the hourly
trends for a slower drop in temps most of the night, while still
maintaining a narrow window around daybreak for frost formation. If
anything it will be lighter and more patchy than advertised, but it
remains a good bet in any of the typical cold spots such as
sheltered valleys. Fog potential already limited to river valleys,
and that is still on track.
&&
.Short Term...(This evening through Thursday)
Issued at 230 PM EDT Wed Oct 17 2018
...FROST ADVISORY TONIGHT AND EARLY THURSDAY MORNING...
Still have the same concerns on bust potential for the frost as the
previous forecast. Typically the first night after a cold frontal
passage is too mixy for that frost to form. Also, an upper wave
bringing a narrow band of high clouds is forecast to move out of the
Red River valley into KY late tonight. All that said, the frost tool
we use, which takes into account wind and sky cover, still is going
for widespread frost along and north of a line from HNB to Etown to
Liberty, with areas of frost...the next category down in coverage...
forecast down close to the TN border. Briefly considered cancelling
part of the advisory close to the TN border, but given statistical
guidance calling for mid 30s at BWG, the chance still is there. The
other potential is for fog development along river valleys, as steam
fog develops with air/water temperature differences of around 25
degrees or greater.
That wave of clouds will be through the region by late morning, so
the rest of Thursday looks great, though chilly, with highs 10-15
degrees below normal.
.Long Term...(Thursday night through Wednesday)
Issued at 233 PM EDT Wed Oct 17 2018
Thursday night the center of the cold surface high that brought
frost to portions of the region in the short term will move off to
Virginia, allowing temperatures Thursday night to be a couple of
degrees warmer than Wednesday night. Readings will bottom out in the
mid 30s, so some patchy frost will still be possible.
Friday clouds will increase from west to east over the course of the
day as a cold front approaches. Rain chances will increase
dramatically by evening with most folks receiving precipitation
Friday night. The system will then pull off to the east on Saturday,
with wrap around clouds and possibly some patchy sprinkles or
drizzle lingering. In our position between the storm system to our
east and a strong Canadian high over the Northern Plains, Saturday
will be rather breezy with gusts of 20-25mph possible.
That strong high to our west will slide across the Ohio Valley
Sunday and Monday with some very chilly air. With the center of the
cold dome to our west Sunday morning and our east Monday morning we
won`t have ideal conditions here for a freeze, but frost still looks
like a good bet Monday morning and possibly Sunday morning.
Monday night/Tuesday a cold front will come at us from the northwest
but it will be falling apart and not associated with any
precipitation (though there will be an increase in upper clouds).
Then the next Canadian high will push into the Great Lakes and give
us more dry and cool weather mid week.
&&
.Aviation...(00Z TAF Issuance)
Issued at 650 PM EDT Wed Oct 17 2018
Decent post-frontal NW wind surge is ongoing, but should lay down
after sunset. Expect light north winds overnight, picking up out of
the NE Thu morning but remaining less than 10 kt. Otherwise look for
VFR through the TAF period, with cirrus from a southern Plains
disturbance not expected to be enough for a ceiling.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...Frost Advisory from 2 AM EDT /1 AM CDT/ to 10 AM EDT /9 AM CDT/
Thursday for INZ076>079-083-084-089>092.
KY...Frost Advisory from 2 AM EDT /1 AM CDT/ to 10 AM EDT /9 AM CDT/
Thursday for KYZ023>043-045>049-053>057-061>067-070>078-081-
082.
&&
$$
Update...RAS
Short Term...RJS
Long Term...13
Aviation...RAS
Area Forecast Discussion
National Weather Service Miami FL
817 PM EDT Wed Oct 17 2018
.UPDATE...
Radar is currently quiet with a stray shower or two over the
Atlantic ocean pushing westward. Easterly winds at 5 to 10 mph are
indicated by the latest observations along the east coast
beaches with light and variable winds elsewhere. Meso-scale
guidance, including the HRRR and Hi-Res WRF, prog isolated
showers to develop along Broward and southeast Palm Beach
counties overnight. Therefore, increases PoP coverage over
portions of the east coast metro to account for this. Otherwise,
all other variables looked on track.
&&
.PREV DISCUSSION... /issued 733 PM EDT Wed Oct 17 2018/
AVIATION...
Rain chances remain very low for tonight with VFR prevailing
through the next 24 hours. The breezy easterly to southeasterly
flow should resume on Thursday afternoon with speeds around
12-13kt.
PREV DISCUSSION... /issued 404 PM EDT Wed Oct 17 2018/
DISCUSSION...
SHORT TERM: Latest GOES16 WV imagery showed deep mid-level ridging
over the Southeastern CONUS. Clockwise flow around this feature
has allowed for persistent breezy east winds across the Southern
portions of Florida. Satellite derived PWATS indicate less than
exceptional values at 1.5". Shower activity has been minimal today
as mostly dry conditions have prevailed. Through this evening,
the HRRR and Hi-res WRF guidance depict shower development in
western Collier counties then have them diminishing after sundown
with the loss of diurnal heating. Breezy easterly winds are
forecast along the east coast beaches tonight with light and
variable winds elsewhere. Easterly flow and shallow moisture will
allow for the development of isolated showers along the eastern
third of the peninsula. Minimum temperatures are expected to be
near 80 along the east coast metro areas, values up to 5 degrees
above normal for this time of year, and mid-70s elsewhere.
LONG TERM: At least subtle changes continue to be hinted at by
global guidance for the weekend and early next week. Upper-ridge
should weaken and drift southeastward, allowing some influence in
South Florida from mid-latitude longwave trough that will progress
through the eastern CONUS this weekend. A weakening cold front is
forecast to approach central Florida Friday night into Saturday,
then be reinforced by another weak front that appears poised to
reach South Florida later Sunday into Monday. Although both GFS
and ECMWF show the front having little dynamical support or
significant moisture pooling for more than scattered convection,
they differ in the magnitude of any cooler (i.e. drier) air behind
the front. ECMWF suggests a slightly more pronounced FROPA, with
early next week yielding dewpoint values in the 60s and
temperatures down toward normal. GFS has front stalling over far
southern Florida will little in the way of drier air and only
lower temperatures to result from curbed diurnal heating from
clouds/scattered showers.
MARINE...
With high pressure dominating the South Florida waters, moderate
east wind will prevail into the weekend with only isolated
showers and thunderstorms. At times, wind speeds may reach 15 kts
and small craft should exercise caution, particularly overnight
in the Atlantic.
AVIATION...
Isolated Atlantic showers could produce MVFR cigs briefly this
afternoon. Some convection later in the afternoon and evening
could affect APF. Rain chances are not quite high enough to
include any other restrictions at this time. The breezy easterly
to southeasterly flow should continue with some easing during the
overnights.
BEACH FORECAST...
East wind of 15 to 20 mph has persisted for several days and will
continue for several more. This has increasingly favored rip
current generation along the east coast and there is now a High
Risk of Rip Currents on Atlantic beaches today. A moderate to high
risk will likely continue on the east coast into the weekend.
&&
.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach 77 88 77 87 / 20 20 20 20
Fort Lauderdale 80 88 79 87 / 30 20 20 20
Miami 78 88 77 87 / 20 20 20 20
Naples 74 90 73 90 / 10 30 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
GM...None.
&&
UPDATE...11/HVN
DISCUSSION...11/HVN
MARINE...11/HVN
AVIATION...17/AR
BEACH FORECAST...11/HVN
Area Forecast Discussion
National Weather Service Springfield MO
623 PM CDT Wed Oct 17 2018
...Updated for 00Z Aviation Discussion...
.SHORT TERM...(This evening through Thursday)
Issued at 229 PM CDT Wed Oct 17 2018
Temperatures have warmed up nicely into middle to upper 60s this
afternoon given a dry airmass in place. High pressure over Iowa
was providing a steady north wind this afternoon. Extensive cirrus
was spreading northeast into the area from the south and this will
be key in regards to overnight low temps and frost potential.
Forecast soundings from the RAP and NAM overnight show that the
cirrus/high cloud cover should encompass at least the southern
half of the area overnight. This will keep low temps from falling
to their max potential. Low temps generally range from the middle
30s in the VIH area to around 40 across the BBG and JLN areas. Do
think there will still be some frost potential in the eastern
ozarks therefore the Frost Advisory remains in effect out there
however did trim back counties on the western edge where it
appears there will just be too much cloud cover to promote
widespread frost.
Thursday looks to be similar to today with perhaps a little more
high cloudcover keeping temps from reaching as high as today.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 229 PM CDT Wed Oct 17 2018
Shortwave energy approaches from the southwest late Thursday night
into Friday with increasing rain showers as that system moves
through on Friday. Forecast soundings indicate little if any
instability at this time therefore will be keeping thunder chances
out of the forecast. Rainfall amounts look light with the majority
of the rainfall south of Interstate 44.
A strong cold front moves through late Friday night and will bring
a reinforcing shot of cool air to the region for the weekend. Low
temperatures Sunday morning look to drop into the lower 30s as
high pressure moves overhead. Widespread frost and perhaps a light
freeze may occur during this time.
Rather quiet/benign weather is then expected until the middle of
next week when additional disturbances approach from the
southwest to provide rain chances.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 623 PM CDT Wed Oct 17 2018
VFR flight conditions are expected across the area through the TAF
period. Only high level clouds expected with northeast winds
becoming more east northeast Thursday afternoon at less than 12
knots.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...Frost Advisory from 1 AM to 9 AM CDT Thursday for MOZ057-058-070-
071-082-083-098.
KS...NONE.
&&
$$
SHORT TERM...Burchfield
LONG TERM...Burchfield
AVIATION...Raberding