Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/18/18
Area Forecast Discussion
National Weather Service Caribou ME
1000 PM EST Sat Nov 17 2018
.SYNOPSIS...
A cold front will track across the region tonight. High
pressure moves over the area Sunday and moves east Sunday night.
A weak area of low pressure is expected to move up across the
Gulf of Maine on Monday.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
930 PM Update: Adjustments were made to fcst cld cvr (from
latest sat imagery) and PoP tmg late this eve into the late
ngt as a weakening cold front crosses the FA. Latest radar ref
imagery shows lgt sn shwr returns particularly ovr E Cntrl ptns
of the FA, but no reports of any snfl from KMLT when echoes
passed ovrhd there. We xtnded the mention of flurries a little
further S into E Cntrl ptns of the FA for the next 2 to 3 hrs,
with most of the echoes xpctd to move E into NB prov by 06z.
Lastly, fcst hrly temps/dwpts were adjusted into the late ngt
from latest mid eve sfc obs. Most of the temp fall needed to
reach fcst daybreak lows, which were raised 2 to 3 deg F across
the N and 1 to 2 deg ovr Cntrl/Downeast areas from warm bias
trends against the prev fcst, will have to occur post frontal
passage late tngt when skies clr.
Orgnl Disc: Clouds holding on and will continue to do so into
the evening. Weak waa in place attm w/pre-frontal trof moving
across the region. Temps into the low/mid 30s north and central
areas while upper 30s to lower 40s from the Bangor region to the
coast. Some flurries/light snow showers popped up across the n
and w but mainly isolated in coverage. Deep moisture in place
from 925-700mbs per the LAP/RAP soundings. This is confirmed by
the 12Z UA and latest obs. The 12Z NAM is showing some potential
for snow shower activity to develop ahead of the apchg cold
front later this evening through around midnight or so. Some
decent caa noted on the UA as well as the NAM. Steepening llvl
lapse rates(7.0+ c/km) w/CAPE OF 40+ joules could lead to some
snow showers and perhaps a brief squall. The area for the
highest threat for this activity will be across the Maine
Central Highlands and the Mt. Katahdin region. The RAP guidance
is similar to the NAM but its placement is different w/any
activity further s. Attm, decided to add 20-30% for snow showers
in the aforementioned areas. Any snowfall accumulations will be
trace amounts to a few hundreths. Temps will be held up through
midnight until the cold fropa. There does appear to be enough
of a pres gradient to keep winds around 5 mph or so. This will
offset any dramatic cooling. As a matter of fact, the best
chance for cooling will be across the Bangor region and interior
Downeast as some clearing is expected w/the wnw wind.
Therefore, overnight temps were brought up from the previous
forecast especially for the north-central and western areas.
High pres set to ridge across the region on Sunday w/mostly
sunny skies and and light winds. It will be cooler than today
and well below normal
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
Forecast confidence remains below average for this time with
periods of rain/snow on the coast and snow further inland.
Generally pattern will remain broad cyclonic 500mb flow over the
state. The first wave to bring the chance for snow to the area
is still the Monday morning weak coastal low which could bring a
few inches to the coast, but air temps are expected to get above
freezing so any snow that does fall could melt. Timing wise
though, there could be some slick roads for Monday morning
commute. Next forecast issue is the Tuesday wave with large
spread continuing in guidance, although some increased consensus
expected the ECMWF remains an outlier with no snowfall. Looks
like there will be a broad elongated inverted trough across the
state with mid-level convergence. Due to the lack of consistency
when with a superblend approach on pops and qpf. Will have to
see if things iron out on this wave in the next 24hrs.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Record Cold Possible for Thanksgiving...
General cyclonic flow expected for this period with an arctic
boundary to impact the region Wednesday or Wednesday night.
Could be snow showers and gusty winds with this front during a
busy travel period, will have to watch this. Confidence is still
high for a blustery near record cold Thanksgiving with a very
anomalous airmass pushing into the areas. Wind chill values on
Thanksgiving day could stay below zero for some areas with a
strong NW wind, it will not be a pleasant day for an outside
walk. Quiet weather is finally expected at this time for Friday
and Saturday, with a moderating airmass.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: Mostly VFR conditions are expected. Isolated snow
showers are possible with a cold front late this evening...mostly
towards GNR. There could be a brief period of MVFR this evening
for the northern TAF sites.
SHORT TERM: Potential tempo IFR conditions by Monday for
KBGR/KBHB with light snow causing low cigs and vis. Confidence
is still low on this wave. Another low confidence coastal rain
and interior light snow event could impact the region on
Tuesday.
&&
.MARINE...
NEAR TERM: Decided to pull the intra-coastal zone out of the
SCA. Extended the SCA for the outer zones through 4 am Sunday.
Winds will pick up w/the cold fropa and gusts to 25 kts are
expected. Those winds will drop off on Sunday as high pres moves
in from the w. Seas were running high today averaging 7-9 ft
which was much higher than what the local wave guidance
predicted. A south swell w/a period of 11 seconds helped keep
those seas up. Decided to blend in the NAM Swan guidance as it
was initializing close to reality at 18Z. This guidance shows
the seas dropping back overnight into Sunday as the swell
weakens.
SHORT TERM: After an active 2 week period no SCA conditions are
expected over the coastal waters Monday through Wednesday. An
arctic cold front will cross the waters on Thursday bringing
potential SCA or higher conditions.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory until 4 AM EST Sunday for ANZ050-051.
&&
$$
Near Term...VJN
Short Term...Dumont
Long Term...Dumont
Aviation...VJN/Dumont
Marine...VJN/Dumont
Area Forecast Discussion
National Weather Service Charleston SC
1058 PM EST Sat Nov 17 2018
.SYNOPSIS...
The region will remain situated between high pressure and a
coastal trough into early next week. A cold front is expected
to move through the region by mid week, followed by high
pressure through mid to late week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
As of 1050 PM: Weak showers have slipped into AMZ374. The trend
of the showers have been weaker. However, I will maintain very
low PoPs and light QPF.
As of 815 PM: KCLX detected a few showers just east of AMZ374,
tracking slowly east. The latest HRRR indicates that showers
will gradually develop within an inverted trough, developing
near the GA coast around daybreak. I will maintain SCHC PoPs
along coastal counties, mainly from the mouth of the Savannah
River south along the GA coast.
As of 510 PM: Latest IR satellite indicated a large area of
cirrus clouds streaming east over the forecast area. I will
update the forecast to increase sky cover across the region this
evening and overnight. Otherwise, the forecast appears in good
shape.
Previous Discussion:
Clear and calm early this evening, then northeast winds will
increase slightly overnight as a coastal trough develops. Weak
isentropic ascent will allow stratocumulus to develop along the
GA coast and spread inland toward daybreak. A few light showers
may brush the GA coast around daybreak Sunday. Lows will be in
the 40s.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
Sunday through Monday: Pooling of lower tropospheric moisture
in the vicinity of a coastal trough will support isolated/scattered
showers, especially east of I-95, Sunday into Monday morning.
Then, any showers should push offshore Monday afternoon as drier
air begins to spread into the area from the W/NW. High temps
will average in the upper 60s north to lower 70s south both
days.
Sunday night: Low temp/dewpoint spreads and light winds could
support some fog, although cloud cover could limit fog potential.
Otherwise, low temps will range from the upper 40s inland to
mid/upper 50s on the beaches.
Monday night and Tuesday: A weak, dry cold front will push through
the region, and building high pressure will continue to usher drier
air into the area. Dewpoints will decrease somewhat, but another
night of low temperatures in the mid/upper 40s inland/50s at the
coast will give way to another day of highs in the mid/upper 60s
north and lower 70s south Tuesday.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A likely dry surface cold front looks to cross the forecast area
late Tuesday or very early Wednesday, followed by additional high
pressure which should persist into late next week. Model divergence
increases by the end of the week. Onshore flow and increasing
moisture levels will set the stage and a developing coastal trough
or possible surface low could provide the forcing for precipitation
production heading into the weekend.
&&
.AVIATION /04Z SUNDAY THROUGH THURSDAY/...
VFR through 00Z Sunday. Cirrus will likely stream east across
the area through late tonight, sourced out of the Deep South.
Late tonight into the pre-dawn, stratus should increase from the
east, mainly over KSAV. These clouds are expected to remain VFR.
Extended Aviation Outlook: Brief periods of flight restrictions will
be possible Sunday night into Monday morning due to the potential
for showers and perhaps even low clouds/fog. Otherwise, VFR.
&&
.MARINE...
Weak northeast winds will gradually increase overnight as a
coastal trough takes shape. Seas will also rise slightly during
the overnight.
Sunday through Thursday night: Winds and seas are expected to
remain below Small Craft Advisory levels through midweek. Then,
a tightening northeast pressure gradient could translate to SCA
winds/seas by Thursday.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.
&&
$$
NEAR TERM...NED
SHORT TERM...SPR
LONG TERM...JMC
AVIATION...NED/SPR
MARINE...JRL/SPR
Area Forecast Discussion
National Weather Service Des Moines IA
525 PM CST Sat Nov 17 2018
...Updated 00z aviation discussion below...
.SHORT TERM.../Tonight through Sunday/
Issued at 333 PM CST Sat Nov 17 2018
Confidence: Medium to High
Main concern tonight will be lingering frontal boundary aloft over
southern Iowa. With a slight east to southeast component in the
H850 winds in Missouri and continued isentropic lift into
southern Iowa, most of the models are indicating snow now in the
south with the potential for up to 2 to 3 inches through 06z. Will
continue the advisory over the south and expand slightly north
and east this evening. The newer HRRR model runs have been more
consistent in at least 2 to 3 inches over most of the south. There
is some uncertainty as to how far east to bring an advisory due
to slightly warmer temperatures in the southeast at this time. For
now, will extend it to Lucas and Wayne Counties and see if a more
narrow band sets up between Chariton and Ottumwa this evening
with the possible need for a few more counties added there.
Meanwhile, high pressure will build into northern Iowa with
continued clearing skies. Snowfall from last night and this
morning combined with the clear conditions will lead to quite cold
temperatures there. Over central and southern Iowa, clouds will
linger with clearing taking place around 06z from Highway 30 north
and from I80 north by 12z. There are minor differences in the
speed of the departing trough overnight with the GFS slightly
faster by 12z Sunday. Hires model forecasts support the same trend
with general clearing nearly across the entire area by sunrise on
Sunday - with lingering high clouds mainly in the south. Lows for
the region tonight will likely range from the single digits north
to the mid teens to lower 20s over the south. The coldest
temperatures will occur near the ridge axis over the
north/northeast coincident with the deeper snow cover.
.LONG TERM.../Sunday night through Saturday/
Issued at 333 PM CST Sat Nov 17 2018
/Sunday Night through Thursday Night/...
Confidence: High
Few concerns for this period. Overall the pattern relaxes with
upper level northwest flow becoming more zonal as H500 heights build
over the Central Plains as an upper level ridge shifts east. This
will continue to promote adiabatic warming with downslope winds east
of the Rockies. Eventually, by Tuesday afternoon continuing into
Thursday, H850 temperatures will warm to 4 to 5C with southwest flow
aloft. This will promote highs in the 30s north Wednesday with 40s
south...by Thursday and Friday, 40s to lower 50s will become more
common.
/Friday through Saturday/...
Confidence: Medium to High
Late in the period, both the GFS/Euro show a southern stream storm
moving into the Plains. Some timing differences remain, but overall
the better forcing/moisture transport arrives Friday into Friday
evening through Saturday. The structure of the storm in both models
is similar with the system occluding as it tracks through our area.
Also, both models suggest that most of the precipitation will
remain liquid with some hint of a transition later Friday night
into Saturday over the northeast. Though the storm appears to be
modest in strength, farther north into Minnesota/Wisconsin there
may be a few issues with impacts on Saturday as the system pulls
out.
&&
.AVIATION.../For the 00Z TAFS through 00Z Sunday evening/
Issued at 519 PM CST Sat Nov 17 2018
Categorical restrictions will continue through this evening. The
worst conditions are expected in southern Iowa where snowfall
may drop conditions in LIFR at times, including the KOTM terminal.
Cigs gradually improve as stratus deck moves south tonight. VFR
conditions will prevail area wide after daybreak Sunday.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until midnight CST tonight for
IAZ072>075-081>086-092>097.
&&
$$
SHORT TERM...REV
LONG TERM...REV
AVIATION...Martin
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
854 PM CST Sat Nov 17 2018
.UPDATE...
Very minor updates to the ongoing forecast as it is in good shape
based on current observations and the latest short term models. Based
on radar trends and high-res output have dropped PoPs prior to
midnight down to only 20 percent across the area. PoPs do increase
after midnight as the front approaches. Frontal timing still looks
good based on the latest runs of the HRRR and the afternoon runs of
the ARW and Texas Tech WRF. Also timing out the front which can be
seen on the KSJT and KDYX radars the front still looks like it will
arrive in the Hill Country between 1am and 3am, then the I-35
corridor between 3am and 6am, and then the Coastal Plains and
southern Rio Grande Plains after 6am. Showers are still expected to
develop along and ahead of the front as well. Showers will continue
behind the front on Sunday as temperatures remain in the 50s.
&&
.PREV DISCUSSION... /ISSUED 555 PM CST Sat Nov 17 2018/
AVIATION.../00Z TAFS/
Moisture return continues in advance of approaching cold front that
that will move through the region overnight and early Sunday. Front
expected around 11Z AUS/DRT and 12Z SAT/SSF. MVFR cigs will develop
all locations starting around 04Z east and around 08Z for KDRT. Will
likely see brief period in advance of the front with IFR cigs. Cigs
will return to MVFR after frontal passage. Northerly winds will be
10-15 knots behind the front with occasional gusts to 20 knots
through early afternoon. After 20Z northerly winds will gradually
decrease to near 10 knots. Expect some streamer showers across the
east in advance of the cold front and post frontal light rain/showers
for several hours after the front passes.
PREV DISCUSSION... /ISSUED 246 PM CST Sat Nov 17 2018/
SHORT TERM (Tonight through Sunday Night)...
A surge of low to mid level clouds signals the approach of the next
weather system for tonight. A cold front will arrive in the pre-dawn
hours over the Hill Country and should push through our southern
counties by 15Z. After 06Z tonight showers will begin to form in the
warm sector mainly near and south of SAT through 09Z and then begin
forming along the front as it enters our northern counties between
09Z and 12Z. The troughing pattern over Canada and the Nrn US
responsible for the front is quite dampened over the Central US as a
persistent zonal pattern aloft remains over TX. Thus the front is
expected to produce moderate cooling and will remain shallow enough
to produce overrunning rain chances through the weekend.
There`s a slight chance of thunder over parts of the Coastal
prairies early Saturday but mainly due to deeper moisture and not
from any dynamic support aloft. The Sunday overrunning pattern should
focus mostly east of Highway 281 where the elevated moist layer is
deeper.
LONG TERM (Monday through Saturday)...
The overrunning pattern weakens slightly and pulls east Monday, but
cloud cover and light NE winds keep clouds overhead for continued
cool max temps. Another weak polar trough drops through the Midwest
and brings another front into TX for early Tuesday. This push of
frontal air should be drier and deeper, so we should see some
partial clearing over the northern counties at least for Tuesday
afternoon. The drying trend is short-lived as a disturbance moving in
the zonal pattern aloft is on track to bring a quick round of rain
chances by Wednesday. Another disturbance passing mainly north of TX
into the Central Plains Thursday will hold the winds over our area
out of the E/NE and maintain mostly cloudy to cloudy skies through
Thursday night. While there isn`t much of a frontal push into South
TX with this system for Friday, a subsident regime in its wake could
clear out the low level moisture for Friday afternoon. The rapid fire
of these zonal disturbances are often handled poorly on timing and
locations, so the chance of rain and frontal impacts could be off
mainly in timing. The deterministic 12Z GFS/ECM runs show poor
agreement for next weekend to reflect this low confidence, the
general trend is that the weather should remain cool but relatively
mild by late November standards for the holiday weekend. Rain chances
look to be low, but that could change with the tracks of the fast
moving zonal perturbations.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 74 52 55 43 54 / 0 40 40 50 50
Austin Bergstrom Intl Airport 73 52 55 43 54 / - 40 50 50 50
New Braunfels Muni Airport 73 55 56 44 54 / 0 50 50 50 50
Burnet Muni Airport 71 46 53 40 55 / 0 30 20 30 30
Del Rio Intl Airport 72 53 57 47 62 / 0 10 20 20 10
Georgetown Muni Airport 72 48 54 40 54 / 0 40 30 40 40
Hondo Muni Airport 70 56 60 46 59 / 0 30 30 40 30
San Marcos Muni Airport 72 55 56 44 54 / 0 40 50 50 50
La Grange - Fayette Regional 73 57 59 45 53 / - 40 70 60 50
San Antonio Intl Airport 70 56 57 45 56 / 0 40 40 40 50
Stinson Muni Airport 72 58 59 46 57 / 0 50 50 40 50
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Aviation...10
Short-Term/Long-Term...Treadway
Area Forecast Discussion
National Weather Service Hastings NE
535 PM CST Sat Nov 17 2018
.SHORT TERM...(This evening through Sunday)
Issued at 239 PM CST Sat Nov 17 2018
Focus continues to be on expected snowfall for mainly this
afternoon and into the evening, mainly between 2 pm and 10 pm.
Much of the support for this snow will come with a 725 mb
frontogenetic band that will quickly spin up and fade along with
the help of a minor jet streak near 300 mb. Higher snow to liquid
ratios could snag an inch or two with this combo, especially in a
band from near Lexington to Hastings to Geneva/Hebron. The band on
radar this afternoon across a good portion of the
central/northeast CWA should sag a bit south with time, although
latest HRRR suggests that it may be hesitant to do so. With the
combination of snow and brisk wind gusts, visibility will be below
one mile at times, and road surfaces are expected to get slick in
spots, so a winter weather advisory has been issued for areas
roughly south of Highway 92 to the Nebraska/Kansas state line.
By midnight, wind speeds should decrease significantly as the
surface pressure gradient relaxes.
This is a glancing blow of arctic air, as we will already be
getting some warm air advection by Sunday afternoon, and
moderating temperatures in the upper 30s for highs near the tri-
cities, compared to the frigid lower 20s for this afternoon.
.LONG TERM...(Sunday night through Saturday)
Issued at 239 PM CST Sat Nov 17 2018
Still a moderating trend for next week, but perhaps a bit of rain
southeast of the tri-cities by late Thursday night/Friday.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday)
Issued at 526 PM CST Sat Nov 17 2018
Expect IFR conditions for the first couple hours as light snow
bands continue across the area. These frontogenetic-driven bands
should gradually drop south and winds will decrease this evening
as surface high pressure builds down from the north. Expect the
snow to be south of both terminals by midnight with clearing
expected overnight and during the day on Sunday.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...Winter Weather Advisory until midnight CST tonight for NEZ041-
047>049-060>064-072>077-082>087.
KS...None.
&&
$$
SHORT TERM...Heinlein
LONG TERM...Heinlein
AVIATION...Ewald
Area Forecast Discussion
National Weather Service Green Bay WI
505 PM CST Sat Nov 17 2018
Updated aviation portion for 00Z TAF issuance
.SYNOPSIS...
Issued at 211 PM CST Sat Nov 17 2018
Remaining rather cold through Thanksgiving Day, then temperatures
warming to above normal for the remainder of the holiday weekend.
The persistent, broad, deep longwave trough that has been across
the area will remain in place a little longer, though a
transition to a more progressive pattern is already beginning out
in the Pacific. The effects of the pattern change won`t become
apparent until after Thanksgiving Day, when the upstream ridge
progresses into the area. There are some indications that the
pattern change won`t last long. Although there isn`t great
agreement among the medium range models, the overall trend seems
to be for the mid-continent upper trough to return.
Temperatures will remain below normal through Thanksgiving Day,
then warm to above normal levels as the flow flattens. There will
be a few opportunities for precipitation, but none look
significant. So totals will probably end up AOB for the period.
Normal precipitation for a week at this time of year is a little
less than one-half inch for most of the area.
&&
.SHORT TERM...Tonight and Sunday
Issued at 211 PM CST Sat Nov 17 2018
The latest RAP analysis and satellite/radar imagery show Arctic
high pressure building southeast across the northern Plains and
into the western Great Lakes. Cold advection continues on the
eastern periphery of the high thanks to northwest winds. The cold
low level airmass with help from moisture fluxes off Lake Superior
continue to generate broken strato-cu over north-central and
northeast WI. Drier air is making progress across northwest WI,
and should see some clearing occur late this afternoon from west
to east. Forecast concerns generally revolve around sky cover and
temps in the short term.
Tonight...High pressure will continue to edge southeast tonight
across the Plains, but also nose into the western Great Lakes.
Dry air with the incoming ridge axis will continue to spread east,
and continue the trend of clearing skies. Eastern WI will be the
last to clear, most likely by mid-evening. Will still have the
northern edge of some cirrus pass over areas south of highway 29
overnight, but without much consequence. The pressure gradient
will remain relatively tight tonight, so remained conservative
with low temps despite skies becoming mostly clear. Lows ranging
from the single digits over the northwoods to the upper teens near
Lake Michigan.
Sunday...The surface ridge axis will slide southeast into the
southern Great Lakes while a weak cold front drops south over Lake
Superior. The northern branch of the jet stream will likely push
some cirrus to the area through the day, but clouds along the
front will most likely remain north of the region. With a breezy
west to southwest wind, highs will range from the mid 20s in the
north to the low 30s over the Fox Valley.
.LONG TERM...Sunday Night Through Saturday
Issued at 211 PM CST Sat Nov 17 2018
A shortwave and surface trough/front will drop southeast across
the area Sunday night into Monday. A broad but rather weak area of
QG forcing along with some FGEN forcing will accompany the
features through the region. The result should be a round of light
snow, especially across the north. Lake-effect snow showers off
Lake Superior will linger in the snowbelt as the system snows
depart.
The large scale flow will become progressive by the time the next
shortwave digs southeast into the longwave trough position
Tuesday/Tuesday night. Given the rising upper heights, chance
PoPs (mainly across the north/northeast) seemed adequate to cover
the situation for now.
The upper changes will cause the next incoming anticyclone to pass
north of the area. The resulting low-level easterly flow across
Lake Michigan could lead to some flurries in the east early on
Thanksgiving Day.
The situation for the remainder of the forecast period is more
muddled. Another precipitation event is possible late in the
period as the remnants of the western ridge shift through the area
and the upper flow tilts back to the southwest. But considerable
uncertainty exists concerning the timing and track of the
resulting weather system. But in any case, it does not appear
likely to be a major storm.
Other than to better resolve the lake-effect potential, no
significant changes were necessary to the standard forecast
initialization grids.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 500 PM CST Sat Nov 17 2018
Skies will continue to clear from north to south this evening as
high pressure builds in across the western Great Lakes. Generally
clear skies are expected until Sunday afternoon across the north
and west when a low pressure system approaches Lake Superior.
Despite the clouds, ceilings should be VFR throughout the TAF
period.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS.......Skowronski
SHORT TERM.....MPC
LONG TERM......Skowronski
AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Jacksonville FL
932 PM EST Sat Nov 17 2018
...SEASONALLY COOL LOW TEMPERATURES TONIGHT WITH INCREASING
COASTAL CLOUDS...
.UPDATE...
A coastal trough was forming offshore of the local Atlantic coast
with a surface high pressure wedge extending southward from the
Carolinas to across central GA and the FL panhandle. High cirrus
clouds spewed overhead within the sub-tropical jet. Locally,
temperatures were trending warmer with an increase in low level
moisture compared to this time last evening due to developing low
level onshore flow.
Expect more mild low temperatures tonight ranging in the
mid/upper 40s inland across SE GA and the Suwannee River Valley to
the low/mid 50s toward the St. Johns River basin and Atlantic
coast. Inland, generally west of Highway 301, potential for
shallow patchy ground fog will exist after midnight where high
cirrus will begin to thin. Closer toward the Atlantic coast,
expect increasing stratocumulus clouds and some spotty shower
activity as coastal trough edges closer toward the coast as
surface high pressure builds farther offshore of the Carolina
coast tonight. Through sunrise Sunday, best potential for showers
will focus along the SE GA coast and adjacent Atlantic waters,
with isolated shower potential along the NE FL coast.
&&
.AVIATION...
As inverted trough axis offshore of the local Atlantic coast
edges farther west through sunrise Sunday, low level moisture will
increase from east to west across the local terminals. Observed
low level cloud bases this evening were generally 3-4 kft from
Daytona Beach southward with this increase in low level moisture,
just above MVFR thresholds. Short range forecast guidance
including the SREF, HRRR and LAMP guidance began to trend less
pessimistic with MVFR ceilings tonight as the trough axis
approaches local terminals. Continued to indicate increasing low
level clouds in the 00z TAF package through tonight, with MVFR
restrictions most likely at CRG, JAX and SSI after 11Z Sunday with
passing coastal showers. Inland at VQQ and GNV indicated MVFR
conditions after 06Z tonight due to shallow patchy ground fog and
potential low stratus. Coastal trough edges farther inland through
Sunday with low level moisture increasing inland through the day
with a low chance of coastal showers as winds transition more ENE
< 10 kts.
.MARINE...
ENE winds near 10 kts will back more NNE tonight as coastal
trough edges toward the local Atlantic coast. Expect an increase
in shower activity through daybreak, especially over waters north
of Mayport. Best chances of showers will focus across SE GA waters
Sunday. Combined seas will range between 2-4 ft nearshore waters
to 3-5 ft offshore waters with swells heights of 1-2 ft and swell
periods of 9-11 seconds. Headlines not expected until potentially
late Thursday.
Rip Currents: Moderate risk Sunday due to easterly winds and
elevated easterly swells.
.HYDROLOGY...
A river flood warning remains in effect for the Altamaha River at
Baxley which is forecast to rise into minor flood Tue through
Thursday.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 46 69 51 71 / 0 10 10 10
SSI 56 71 58 72 / 20 30 20 10
JAX 50 73 55 76 / 10 20 20 10
SGJ 58 74 60 75 / 10 20 20 10
GNV 48 76 54 77 / 0 10 10 10
OCF 50 77 55 78 / 0 0 0 10
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&
$$
Enyedi/Gumbs
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
913 PM CST Sat Nov 17 2018
.UPDATE...
Issued at 847 PM CST Sat Nov 17 2018
PoPs and QPF have been updated to reflect the slower
southeastward progression of the snow band to our north. This has
produced slightly lower snowfall totals across the northern CWA.
Kanofsky
&&
.SHORT TERM... (Through Late Sunday Afternoon)
Issued at 330 PM CST Sat Nov 17 2018
The cold front continues to progress southward through the region,
and at mid-afternoon stretched near a Effingham-Cahokia-Lake of
the Ozarks line. The cold front will continue to move southward
the remainder of the afternoon into tonight with surface high
pressure building into the area and surface winds becoming
northeasterly. Temperatures tonight and into Sunday morning in the
post-frontal air mass do not appear to be as cold as previously
thought. The temperature advection from the northeast component of
the surface wind, which will become a bit more northerly later
tonight, will keep the freezing and below temps largely confined
to the northwest third or so of the CWA. In fact my freezing line
is south of the RAP 2m temperature forecast. As far as precipitation,
the driving mechanism will largely be low-mid level frontogenetic
forcing with a slight contribution of weak large scale ascent
from a passing disturbance in the westerly flow aloft. This is
what is responsible for the west-east band of snow from northern
IL across southern IA into southern Nebraska at this time. This
forcing will move into the area tonight with the aforementioned
frontogenetic forcing aligned across the northern CWA, supporting
a band of rain changing to snow. The marginal temperatures,
forcing, and progged qpf suggest that snow accumulations up to
inch are possible across northeast MO into west central IL tonight
into early Sunday morning, and the best accumulation potential
will be on elevated surfaces. Further south, the precipitation
tonight will be more scattered or spotty in nature associated with
weaker frontogenetic forcing and even weaker large scale forcing
for ascent. The precipitation further south also appears to be
more of a rain or snow situation with more limited southward
extent of freezing temperatures tonight and gradually increasing
moisture in the ice crystal growth zone. All forcing weakens
rather quickly by daybreak Sunday and it remains this way until
early afternoon, suggesting any precipitation will be spotty and
light. During the afternoon a new wave of predominantly rain will
spread from southwest MO into southeast MO, and then across
southeast MO and southern IL in the evening. This precipitation is
associated with a positively tilted migratory short wave and the
entrance region of an upper level jet streak. Thermal profiles
suggest this should be all rain although on the far northern edge
of the precipitation shield there could be a few wet snowflakes
mixing in the evening. This precipitation should exit to the east
by midnight.
Glass
.LONG TERM... (Sunday Night through Next Saturday)
Issued at 330 PM CST Sat Nov 17 2018
Most of the week ahead looks uneventful, dry, and tranquil until
Friday into early Saturday. Northwest flow aloft will dominate
through Tuesday resulting in below average temperatures with
another reinforcing cold shot on Monday afternoon/night. By
Wednesday we see a pattern change with heights aloft on the rise
and a WAA regime becoming established, and this will result in
temperatures rising to near average and maybe above average
Wednesday and beyond. On Friday an approaching upper trof and
associated cold front will bring what looks to be a widespread
rain event.
Glass
&&
.AVIATION... (For the 00z TAFs through 00z Sunday Evening)
Issued at 519 PM CST Sat Nov 17 2018
SPECIFICS FOR KUIN: A broad band of wintry precipitation was
located to the north of the terminal at TAF issuance. It is
expected to slide to the ESE during the TAF period and bring
several hours of light snow to KUIN, although the initial
precipitation type could be a rain/snow mix before it changes over
to snow. Up to an inch of snow accumulation is possible through
18z. Ceilings are expected to remain IFR for at least the first
0-12 hours based on satellite trends and model forecasts. There is
a slight chance that ceilings could improve to MVFR as early as
15z, but it seems more likely that improvement will hold off until
closer to 18z.
SPECIFICS FOR KCOU: A broad area of IFR stratus was moving
southward behind a cold front and should reach KCOU within the
next hour or two. Once ceilings fall to IFR, they will likely
remain so through at least 15-18z before improving slightly to
MVFR. There is a slight chance of precipitation after 06z, but
there is a fair amount of uncertainty regarding whether the
southern edge of the snow will extend as far south as KCOU.
SPECIFICS FOR KSTL, KSUS, KCPS: IFR ceilings will prevail for at
least the first 0-12 hours of the TAF period and likely longer.
These ceilings were present across a broad area and were moving
south behind a cold front. Little improvement in the ceiling
height is expected until after 18z. There is greater uncertainty
regarding the visibility trends over the next several hours.
Melting snow during the day has added a lot of moisture to the
lower levels, and this could produce mist across the St. Louis
metropolitan area through 12-15z despite the winds remaining at
or above 7-8 kts overnight.
Kanofsky
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Springfield MO
546 PM CST Sat Nov 17 2018
...Update to Aviation Discussion for 00Z TAFs...
.SYNOPSIS...
Issued at 217 PM CST Sat Nov 17 2018
Temperatures were actually above average across the area this
afternoon with most places in the lower to middle 60s with
filtered sunshine. A cold front was slowly moving south into the
area and was generally along the US Highway 54 corridor. Much
colder air with temps in the 30s resided across Northern Missouri.
Shortwave energy was moving southeast across Wyoming and will be a
focus for lift across the area tonight into Sunday.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 217 PM CST Sat Nov 17 2018
The cold front will continue to move through the remainder of the
area this evening. Currently have some dry air in the low and mid
levels of the atmosphere so we dont expect any precipitation
through about midnight. After midnight, should start to see some
light precip, likely in the form of drizzle given the lack of
cloud ice across eastern Kansas into central missouri. The NAM is
more bullish with this precip than the RAP and other models.
Surface wind trajectories will be generally out of the northeast,
therefore while cold air will be coming in, not expecting any
freezing temperatures until 09z or after across eastern kansas and
west central missouri. Models have trended warmer with overnight
lows versus previous forecasts, therefore overnight lows were
increased with this forecast. The RAP would indicate temps even
warmer than this latest forecast, however for now we hedged
upward slightly. The freezing line looks to drop to a Pittsburg,
KS to Versailles, MO line by 12z Sunday morning. Therefore may see
some precip briefly change over to freezing drizzle. Models have
periods of no cloud ice and then some hours of saturation, however
for now have gone with freezing drizzle. If cloud ice does indeed
exist, then there could briefly be some sleet since the 850mb
front with colder temps looks to lag into Kansas. Currently not
looking at any accumulation or impacts. With temperatures reaching
the 50s and 60s today, ground and road temps are warm and even
with sfc temps reaching freezing, impacts are not likely to occur.
An area of showers will likely move northeast out of Arkansas
during the morning hours across the rest of the area and last into
the afternoon hours. Temperatures will likely hold into the middle
to upper 30s all day Sunday therefore it will be a cold/rainy
Sunday. All precip looks to stay liquid during the day.
.LONG TERM...(Sunday Night through Saturday)
Issued at 217 PM CST Sat Nov 17 2018
Northwest mid level flow persists Monday through Wednesday with
temps below average but it will be dry. Mid level heights rise
nicely for Thanksgiving Day with temps reaching the upper 50s to
around 60 with dry conditions. Models agree that a shortwave will
approach from the west late Friday with rain chances returning.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 546 PM CST Sat Nov 17 2018
Surface winds of 05-10 kts will gradually veer from southwest to
north this evening in response to a passing cold front. Ceilings
will begin to lower as well, with IFR conditions expected at the
SGF & JLN terminals by about 06Z, and the BBG terminal by 12Z.
Some drizzle or light rain is also expected by early Sunday
morning, with temperatures holding just above freezing.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SYNOPSIS...Burchfield
SHORT TERM...Burchfield
LONG TERM...Burchfield
AVIATION...Albano/Wise