Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/03/18
Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
218 PM AKDT Mon Apr 2 2018
.DISCUSSION...
The main forecast concern will be gusty northeasterly winds and
their influence regarding blowing snow and temperatures across the
forecast area over the next couple of days. Otherwise, fairly
quiet with no large storms anticipated for Northern Alaska.
Latest model solutions consistency and agreement remains good
through early Thursday before solutions start to diverge in the
mid to late forecast period.
Aloft...At H500, strong 567 dam upper level ridge centered over
the Chukotsk Peninsula and extending over the Bering Sea and
Bristol Bay will shift north towards the Eastern Siberian Sea
through Wednesday and then will stayed centered there while
building to the east over the Arctic Ocean and Canadian Arctic
Archipelago through Friday. Meanwhile, a 526 dam low will move
south along the Alaska-Canada border tonight and then will merge
with a 522 dam low over the SE AK panhandle early Tuesday morning.
A strong shortwave will dive south from the high Arctic and over
the North Slope this evening, then south over the Interior by
Tuesday morning pushing the upper level ridge west. The
aforementioned upper low over the SE AK panhandle will slide west
along the Gulf of Alaska through early Wednesday, settling over
the Kuskokwim Delta by late Wednesday afternoon. This low will
then slowly move towards the Yukon Delta by Thursday afternoon.
Surface...A 1046 mb ridge of high pressure centered near 77W 161W
extends southwest over eastern Siberia and northern Bering Sea
with the center building to 1052 mb as it shifts closer to the
Arctic Coast through Wednesday and then will weaken as it shifts
east towards the Canadian Archipelago through Friday. As a result
of the high building and shifting closer to the Arctic Coast and a
weak low over the northern Gulf of Alaska, the pressure gradient
over Northern Alaska will increase, especially over areas of
higher terrain in the Interior, Seward Peninsula, and the western
Brooks Range. Should see the pressure gradient relax as surface
high pressure weakens.
Eastern and Central Interior...Mostly clear skies across the area
will persist into the evening before seeing an increase in cloud
coverage tonight as a strong shortwave drops south. Could see
some flurries over the next couple of days under the influence of
the upper level low and trough. As the upper level low shift west
along the Gulf of Alaska coast, a colder, below normal H850
airmass will shift west over the area. Will see H850 temps drop to
between 15 and 21 below, coldest being over the northern
Interior. This will result in cold mornings over the next couple
days especially for areas that remain clear. By Wednesday, warmer
return southeast flow will develop and persist through Friday. As
the pressure gradient increases over the Interior Tuesday
evening, will see winds pick up and become gusty through Thursday
afternoon, especially over the hills and summits in the Interior.
Given the number of warm days lately allowing for some melting
and settling, not sure of the condition of the snowpack and
whether it will be conducive to blowing and drifting to the point
of generating low visibilities. However, the combination of gusty
northeast winds and cold temperatures may result in cold wind
chill values Tuesday night into Wednesday.
West Coast and Western Interior...Low ceilings in stratus persists
over Gambell and to the north of the island with fog quickly
dissipating over the last hour or so. As stated in previous
discussion, the HRRR has been preforming exceptionally well over
the last couple of days. Thus will be expecting areas of fog to
develop again over Saint Lawrence Island and then spreading east
over Norton Sound as well as the Yukon Delta coast tonight, then
dissipating by noon tomorrow. The pressure gradient will tighten
considerably to the south of the western Brooks Range tonight over
zones 208 and 217. Will keep the winter weather advisories for
blowing snow out for these two zones as low visibilities in
blowing snow are likely with gusty northeast winds tonight through
late Wednesday evening. The pressure gradient will tighten up
resulting in gusty northeast winds developing Tuesday elsewhere
on the West coast and Western Interior. Temperatures will be
cooler over the next couple of days as a colder H850 airmass moves
overhead. Should see temperatures warm some by Friday.
North Slope and Brooks Range...Surface high pressure sitting to
the north of the Arctic Coast will allow fairly quiet weather to
prevail across the area. Northerly gap winds are expected to
persist over the western Brooks Range through Thursday. A leeside
trough is expected to develop north of the eastern Brooks Range by
mid week, generating southerly gap winds that will persist into
early this weekend. This leeside trough will also cause the
pressure gradient to tighten locally over the eastern Beaufort Sea
coast that will result in gusty east winds to around 45 mph
Wednesday night through early Friday morning. The HRRR is
indicating that areas of fog will develop and advect inland from
Barrow east after midnight tonight with fog burning off by noon
tomorrow.
Coastal Hazard Potential Days 3 and 4...None.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory for AKZ208-AKZ217.
Small Craft Advisory for PKZ210.
Brisk Wind Advisory for PKZ200.
&&
$$
LTH APR 18
Area Forecast Discussion
National Weather Service Binghamton NY
944 PM EDT Mon Apr 2 2018
.SYNOPSIS...
An approaching warm front will bring rain back into the region
for Tuesday. A light wintry mix is possible as the precipitation
begins early in the morning. A cold front will bring additional
showers, and possibly some thunderstorms, late Tuesday night and
Wednesday.
&&
.NEAR TERM /THROUGH TUESDAY/...
Precipitation will develop across the region toward sunrise as a
warm frontal boundary moves closer then through the region on
Tuesday. The warm advection associated with this feature is
fairly strong with most of the event expected to be in the form
of rain. Thermal fields can support a transition from a light
wintry mix of snow or freezing rain...especially in the cold air
damming favored counties from the Mohawk Valley to the higher
terrain of the Western Catskills and Northern Poconos for an
hour or two. Given time of year, there should be little impact
on roads from light amounts of freezing rain. No plans for a
Winter Advisory at this time with only chance PoPs for FZRA.
With the mid evening update, we scaled back the timing of the
precipitation onset some based on the latest mesoscale model
runs. The latest runs of the RAP and HRRR would keep almost all
of the region dry through the morning commute. These models can
have a slow bias, so the updated forecast keeps open the chance
for light wintry precipitation during the morning commute.
Widespread rain then occurs much of the day until warm front
surges north of CNY/NEPA. Have trended rain chances down in a
gradient from north-south during the afternoon and much of
Tuesday night, and went back to using showers to indicate more
limited chances of precip on Tuesday night. Region will be
entrenched in the warm sector, thus have a non-diurnal
temperature trend with lows only a few degrees off from the
Tuesday high temperatures.
Models suggest some elevated instability developing ahead of the
advancing cold front which comes through Wednesday. Will
introduce a couple of hours mention of thunder potential late
Tuesday night to account for this.
QPF amounts focus on our northern zones with amounts next 48
hours around an inch, or so. This may cause some ponding of
water in some areas, and will likely see rises again on area
streams and the smaller rivers.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
Powerful cold front enters the area Wednesday morning and
sweeps east across the area. Models have elevated instability
near the front may result in the first spring thunder along the
front. Front should be through much of the area by midday and be
followed strong caa and snow showers. Winds will be quite gusty
as the temps tumble into Thursday morning.
Northwest flow continues into Thursday although the airmass
modifies under the strong sun. Lakes effect snow showers will
taper off by the afternoon.
Temperatures will remain below normal through the period as the
extended winter continues.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Yet another powerful system swings through the area Friday
followed by a strong cold front. More rain and snow showers
ahead of the system followed by lake effect snow showers into
Saturday. High pressure builds in late Saturday into Sunday
bringing drier weather and sunshine. Temperatures will continue
well below normal, modifying a bit again on Sunday under the
1027mb high.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
Low pressure in the mid west will lift into the Ohio valley
Tuesday afternoon with its warm front slowly advancing toward
the area. A mid deck will spread across the region later tonight
then conditions will deteriorate as light rain moves into the
region toward daybreak. Conditions will drop into the
IFR/Alternate Min category during the mid/late morning hours
across the southern terminals and into the Alternate Required
category during the afternoon at KRME/KSYR. At KITH/KBGM, the
light rain may briefly fall as light snow between 12Z-14Z.
Light winds overnight becoming E/SE toward daybreak at 10 to 15
knots then SE/S during the afternoon with gusts around 20 knots.
Outlook...
Tuesday night...VFR-MVFR with showers. Local alternate
restrictions possible in areas of fog.
Wednesday...Cold front moves through the region, with winds
becoming W/NW. Flight category reductions remain possible.
Thursday and Friday...Flight category reductions possible with
SHSN/SHRA.
Saturday...Mainly VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...JAB
NEAR TERM...JAB/MWG
SHORT TERM...DGM
LONG TERM...DGM
AVIATION...RRM
Area Forecast Discussion
National Weather Service Denver/Boulder CO
838 PM MDT Mon Apr 2 2018
.UPDATE...
Issued at 838 PM MDT Mon Apr 2 2018
There is a decent sided area of northern and central CWA plains
with northeasterly winds at present. The radars are showing
these winds pushing southeastward. The RAP13 and HRRR do show
this somewhat, but a bit later then currently. The current GFE
grids do have some pops in them and that is good concerning real
date. radars show some echoes along the northern CWA border right
now. The new NAM keeps wind over the plains, northerly will past
06Z tonight. Will amend the GFE grids accordingly. As far as the
high wind highlights go, will leave them as is for this update.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 150 PM MDT Mon Apr 2 2018
West flow aloft has led to lee troughing and warm temperatures
this afternoon. This evening a short wave trough currently over SE
Idaho will dig southeast into Wyoming. Ahead of the trough a fetch
of moisture extends from the Sierras ENE into Utah. Enough
moisture and lift associated with the trough should result in
mountain snow showers late this evening. The back edge of the
moisture is easily visualized on GOES-16 water vapor imagery, and
indications are for a brief period of snow in the central and
northern mountains from this evening through mid-morning Tuesday.
Amounts will be light and generally in the 1-4" range. The
strongest lift remains north of our area and with downslope flow,
no precipitation is expected across the I-25 urban corridor,
Palmer Divide, and eastern Plains. The exception could be the far
northeast Plains (Logan, Phillips, Sedgwick) where a narrow zone
of lift is possible along the deformation zone just behind the
front. Right now the P-type should be rain, possibly changing to
snow at the tail end of the precipitation if any falls. Any
precipitation that falls across the northeast plains will be light
and most likely between 9 pm and 3 am.
The weather story for tonight and Tuesday will be the winds. As
the trough swings southeast across southern Wyoming tonight,
unseasonably cold air at 700 mb will enter the northern half of
Colorado. Cross barrier flow of 70-75 kts looks likely across the
Continental Divide along and north of I-70 into Wyoming from
9 PM through 3 AM. At the same time, ridge top lapse rates bottom
out to ~0 to 3 deg/km, potentially forcing the strongest winds
down the east slopes. A final ingredient for the strong winds in
the mountains and east slopes is synoptic subsidence. The
strongest subsidence on the backside of the short wave trough is
along the Wyoming border around 12Z, not timed ideally for strong
winds but any bit of subsidence could aid in momentum transport.
Thus, have hoisted a high wind warning for the high mountains
north of I-70 and the east slopes. Some of those winds may make it
to the lower elevations adjacent to the foothills early Tuesday
morning, but confidence in the warning criteria being met there is
lower. Highest gusts could be in the 80 mph range, especially in
the wind prone areas above 8000 feet east of the Divide. Once the
subsidence moves east of the mountains after 12Z the highest winds
will be confined to the Plains. Brute force pressure gradient,
full sun, and subsidence are the ingredients for the high wind
warning across the northeast Plains. The lee trough today deepens
into a surface low and gets kicked east as the short wave trough
approaches, and by midnight tonight should be around 988 mb across
E. Kansas. The strongest winds across the eastern Plains are
likely from around 3 AM through noon. The ingredients marginally
support high wind warning criteria, but confidence is high enough
across the area for the warning. Gusts to 60 or 65 mph are
possible through midday. We also have an RFW for E. Elbert and
Lincoln Counties for Tuesday afternoon where fuels are favorable
for rapid fire growth and RH is lowest. See the Fire Wx Discussion
below.
The downslope wind and April sun angle will be offset by 700 mb
temps around -15 and -16 degC by mid afternoon with strong cold
advection much of Tuesday. The result will be high temperatures 20
plus degrees lower than Monday. We expect highs in the upper 40s
to low 50s across the Plains, with the warmest temps east of the
Palmer Divide. Winds should weaken by late afternoon as the low
pulls further east into the Central Plains.
.LONG TERM...(Tuesday night through Monday)
Issued at 150 PM MDT Mon Apr 2 2018
For Tuesday night and Wednesday there will be a moderate northwest
flow aloft over Colorado. There will still be some strong and
gusty winds redeveloping over the mountains late Tuesday night and
Wednesday as cross barrier flow increases to 40-60kt. Appears
strongest winds will remain further higher up along the divide and
exposed higher foothills.
Next system will impact northern Colorado Thursday night and
Friday with the next threat of rain and snow. Models have been
stronger during the past few runs with deeper moisture and upslope
conditions. Have decreased temperatures on Friday and nudged
chances of rain and snow upwards a bit in latest forecasts.
Temporary drying on late Friday but this will be short lived as
next Pacific system will impact mountains with more snow Saturday
afternoon and night. Could be a slight chance of showers on the
plains but overall moisture not that great with not much a upslope
component.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 838 PM MDT Mon Apr 2 2018
Winds at DIA have been west or northwest later this afternoon and
evening. Current radar data indicates a northeasterly wind shift
may graze, at least, the southern half of the airport by 0315Z.
Otherwise, models are sticking with pretty strong north-
northwesterly winds after 06z, then northwesterly after 12Z.
&&
.FIRE WEATHER...
Issued at 838 PM MDT Mon Apr 2 2018
We issued another RFW for zones 246-247 from noon through 6 PM
Tuesday. Winds will be on the high end across all of the eastern
plains with a high wind warning in effect tonight through noon. We
did not issue an RFW for any other areas outside of 246-247
because relative humidity should be above 20 percent across the
northeast Plains in the cold air behind the front, and recent
rains have led to greening up and wetter fuels north and west of
the warned area. Our confidence in fuel status being ready to burn
was high across E. Elbert/Lincoln, not confident across the rest
of the Plains where significant precipitation has occurred the
past week and we haven`t received current fuel status data for
those areas yet.
Will let the RFW ride as is for this update. rjk
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
High Wind Warning from midnight tonight to noon MDT Tuesday for
COZ042-044-046>051.
High Wind Warning until 6 AM MDT Tuesday for COZ033>036-038-039.
Red Flag Warning until 8 PM MDT this evening for COZ246-247.
Red Flag Warning from noon to 6 PM MDT Tuesday for COZ246-247.
&&
$$
UPDATE...RJK
SHORT TERM...Schlatter
LONG TERM...Entrekin
AVIATION...RJK
FIRE WEATHER...Schlatter/RJK
Area Forecast Discussion
National Weather Service Caribou ME
920 PM EDT Mon Apr 2 2018
.SYNOPSIS...
High pressure will slide to the east on Tuesday. A strong area
of low pressure will move toward the region Tuesday night and
then move across the area on Wednesday. This system looks like
it bring some snow to the north and west with rain for
Downeast.
&&
.NEAR TERM /THROUGH TUESDAY/...
9:20 pm update...There is an area of mid level clouds around
7-8k ft agl moving east across northern portions of the cwa.
Most of these clouds should move east of the area during the
next couple of hours. Some high clouds may begin to advance
toward the region well after midnight as a frontal boundary
approaches from the west. Updated with the latest observations,
cloud cover, and the expected conditions the remainder of the
night.
Previous discussion...
The challenges this term will be temps and precip chances on
Tuesday.
Another chilly night setting up as clouds should dissipate after
sunset. Upper level disturbance responsible for the clouds will
be passing to the e w/clearing taking place. Sfc high pres to
the s will ridge across the region and w/winds becoming light
and clear skies, temps will drop off sharply. Areas across the n
and w will temps hit the mid teens w/some sites across the Crown
and back to Allagash Valley and Big Black seeing around 10F. The
Central Highlands and Downeast will see upper teens to lower
teens. Clouds are expected to start moving into the region from
the wsw after midnight as a frontal boundary slide se from
Canada. These clouds will also help to cat off temps. Some of
short range guidance indicated the potential for some fog down
across the Penobscot Valley. The GFS was the most aggressive
w/the fog for the Bangor region. The NAM/GEM and RAP kept the
fog at bay. Therefore, decided against adding any fog the Bangor
region and interior Downeast. Another reason given is that the
llvl will be dry for much of the night and slowly moisten after
12Z Tuesday.
For Tuesday, clouds will continue to increase during the day.
Cloud cover expected to be above 70% by 18z and this will help
to cut down on significant warming. Daytime temps will be some
5-7 degrees warmer than they were today. Some of the short range
guidance was showing some light QPF moving in from the w by
late afternoon including the NAM and GEM as a frontal boundary
slides se into the region from Canada. There is a 50 kt jet
streak noted at 700 mbs that is expected to move into the region
providing the necessary forcing. Llvls look like they will be
dry starting out but should moisten up by late in the day w/help
of sse flow. This should be enough to allow for some light
precip. Attm, it looks like rain/snow or even perhaps some sleet
given the low dewpoints. QPF will light maybe a few hundredths
at best.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
Interesting scenario setting up Tuesday night and into Wednesday
with potential for several inches of snow across portions far
northern Maine, especially the St. John Valley and north Maine
woods.
Low pressure will track east from the Great lakes region Tuesday
night with overunning precipitation developing. The
precipitation is expected to begin in the form of snow across
the entire area Tuesday evening. Across downeast areas,
including the greater Bangor region, expect the precipitation to
turn quickly to all rain as southerly winds transport milder
air north. A much different story farther north, as strong
Canadian high pressure remains north of the border across
eastern Quebec which be slow to retreat resulting in potential
for some cold air damming.
Significant differences exist among the 12z deterministic
guidance this afternoon, with regard to the extent, and how
long the colder air will hang on across the north. The GFS by
far is on the warm end of the guidance spectrum, bringing H925
temps above zero as far north as the St. John Valley, for a
change to all rain even there by Wednesday afternoon. The NAM on
the other hand is stronger with the cold air damming across the
far north, with its H925 temps remaining below freezing through
Wednesday, with more in the way of frozen precipitation
continuing into Wednesday afternoon. EC holds on the to cold air
longer across the far northwest as well, as the primary low
tracks to our northwest with a weak secondary low forming and
tracking toward Houlton, helping to keep the cold air locked in
across the far north.
Have weighted the forecast for Wednesday a bit more toward the
colder model solutions, thus keeping more in the way of
frozen/freezing precipitation going across far northern areas
into Wednesday afternoon. Couldn`t rule out warning level snow
amounts across far northwest Maine (Zone 1), but right now
thinking that most of the populated areas will remain in
advisory level criteria, with the potential for 6 or 7 inches
from Madawaska to Fort Kent. Amounts could get closer to 8 or 9
inches towards Allagash to Estcourt Station by Wednesday
afternoon. Looks like the potential for advisory level snow
accumulations across the remainder of northeast Aroostook,
especially north of Caribou to the St. John valley. With warmer
air coming in aloft, potential for some mixed precipitation
developing by Wednesday morning as well.
Any ongoing precipitation Wednesday evening across the far
north will likely end as a brief period of snow before tapering
to snow showers later Wednesday night as the low tracks
northeast of the region.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Active weather pattern continues in the long term with below
normal temperatures expected.
Fair weather can be expected Thursday night before clouds
increase in advance of the next system approaching from the
Great Lakes region. Uncertainty still exists with regard to the
track of the system later Friday and Friday night. GFS is
farther south and colder, while EC is farther north, thus
warmer. A model blended solution yielded likely pops for much
of the area Friday with snow north and snow or rain down east.
Conditions improve on Saturday, but upper trof across the
region keeps the potential for at least the slight chance for
snow showers, especially north and west. Drier weather returns
early next week, with perhaps another weather system affecting the
area later Monday.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: Looking at VFR into Tuesday. The caveat will be near
KBGR and some MVFR cigs could set up by early Tuesday morning
given the light sse flow. Will need to see how things progress
this evening w/the potential for fog. As referenced above,
decided not to go w/any fog attm given the dry llvls.
SHORT TERM: Widespread IFR conditions expected Tuesday night
through Wednesday in snow/wintry mix/rain north and mainly rain
down east terminals. Patchy fog will also add to visibility
reductions in precipitation Tuesday night into Wednesday.
Conditions should improve to MVFR/VFR all terminals Wednesday
night with northern snow showers still possible. VFR all
terminals Thursday/Thursday night. Outlook for Friday is for
potential widespread IFR in snow/rain. VFR returns Saturday.
&&
.MARINE...
NEAR TERM: Rather tranquil conditions tonight into Tuesday.
S winds will be picking up during the day on Tuesday w/speeds of
10-15 kts. Seas of 2-3 ft w/gradually build to around 4 ft by
early evening.
SHORT TERM: Small Craft conditions Tuesday night will give way
to increasing winds/seas later Wednesday into Thursday with
potential Gale Force gusts possible. A Gale Watch remains up for
later Wednesday into Thursday. Visibility will likely be
reduced in rain and patchy fog Tuesday night through Wednesday.
&&
.HYDROLOGY...
The latest model guidance has shifted things further e w/the
track of the low center. This would mean a cooler scenario
cutting down on significant unloading of the snowpack,
especially across the northern river basins. Northern rivers are
still 90% snow/ice covered and the latest forecast is calling
for up to 6 inches of wet snow in the Northern basins before the
potential for a changeover to rain or a mix of rain/snow. This
snow absorb the initial shot of any rain. Further s across the
Penobscot and Piscataquis basins, some snow/sleet initially
going over to rain. Warmer temps in the 40s and lower 50s will
allow for better snowmelt and runoff leading to some
rivers/streams to rise, but to remain well within their banks.
Therefore, any flooding threat looks to be low including the ice
jam threat for the northern sections for this event. This will
need to be monitored however as a shift back to the w would lead
to a warmer solution leading to substantial runoff/melt.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Gale Watch from Wednesday afternoon through Thursday morning
for ANZ050>052.
&&
$$
Near Term...CB/Hewitt
Short Term...Duda
Long Term...Duda
Aviation...CB/Hewitt/Duda
Marine...CB/Hewitt/Duda
Hydrology...
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1151 PM EDT Mon Apr 2 2018
.AVIATION...
Deep baroclinic zone from 925-500mb will progress steadily northward
overnight lifting into the state during the latter half of the
night. Top down saturation will commence under deep isentropic lift.
Residual low level dry air will be slow to scour out initially, but
will finally give way to a moistening column by mid to late morning.
Rapid transition from MVFR to IFR is anticipated after daybreak
Tuesday. Bulk of the event will be a straight rain precipitation type
for most of the forecast area. A brief wintry mix of -fzdz/-fzra/-sn
will be possible at FNT and MBS at onset. One uncertain part of the
forecast is that snow my be hold as the predominate precipitation
type at MBS for a few hours into the morning Tuesday. Warm
temperatures will limit the impact. Elevated thunderstorms will be
possible over Southeast Michigan, particularly during the late
afternoon/early evening south of the I69 corridor. Confidence in
coverage and timing remains low and will keep the mention out of the
TAFs.
For DTW...Precipitation will advance within vicinity of the airspace
after 10z Tuesday. A very low chance exists for a brief mix of -sn/-
fzdz at precipitation onset. However, this chance remains very low
and predominate precipitation type will be rain. Most favorable time
period for Thunderstorms will be 22Z Tuesday - 02Z Wednesday.
/DTW THRESHOLD PROBABILITIES...
* Low for ceilings aob 5000 this evening. Medium after midnight,
high after 10z.
* High for precipitation type to remain mainly rain Tuesday. Brief
window for -sn/-fzdz at onset Tuesday morning.
&&
.PREV DISCUSSION...
Issued at 328 PM EDT Mon Apr 2 2018
DISCUSSION...
Powerful upper level wave tracking through the Pacific Northwest
today, merging with the subtropical energy along and off the Baja
California Coast tonight-tomorrow, with very impressive 6 hr 500 MB
height falls rolling through the Central Great Lakes/Ohio Valley
tomorrow night, with the -190 M height fall center progged to track
along to the southern Michigan border. Excellent moisture transport
and low-mid level circulation tracking through southern Lower
Michigan will assure precipitation tomorrow, and bumping pops up to
100 percent for late in the day. 850 MB dew pts progged to reach
10-11 C near the southern Michigan border, leading to negative
showalter index south of I-69, roughly 20-2z Wednesday. Obviously 850
MB winds and 0-1 KM bulk shear of 60 knots draw concern for severe
weather, but surface based cape is in question, dependent on surface
low track or triple point. If the 12z NAM track south of the border
verifies, will not have to worry about any tornado threat. Local
probabilistic (SREF) weighted guidance suggests MUCAPES of 500 J/kg
over Monroe county, but very low chance (under 20 percent) of
reaching 1000 J/KG, and preference is to keep the good surface based
instability gradient confined to northwest Ohio. A quick look at the
12z Euro also adds to the confidence any severe weather will likely
be south of the border.
Across the norther third of the CWA, there is snow and/or ice
concerns. Tonight the 700 MB FGEN/front is mainly just north of
Saginaw Bay, with low level feed of moisture advecting in over
southeast Michigan. It appears with the the mild 700 MB temps (just
slightly below zero) and lack of saturation, ice nuclei will be hard
to come by, and thus any light precipitation that develops will be
mostly in the form of cold rain or light freezing rain. Although,
preference is with the Rap which keeps the majority of the night
dry. With surface temps likely in the 30-34 range when precipitation
arrives, doubtful there will be much of an impact before temps rise
above freezing everywhere Tuesday morning, even with the stiff
northeast wind off Saginaw Bay, temps will likely be stuck in the
mid 30s in the Tri-Cities. Northern Midland/Bay counties stand the
best chance of seeing snow during Tuesday, as 925 mb temps lurk
around -3.5 C through 18z, before rising to around -2 C by 00z, per
12z GFS, but other models NAM/Regional Gem are bit warmer, not to
mention the mid level warm layer should make it that far north as
well as with the 850 MB circulation progged to track up that way.
Pronounced Mid level (700 MB) dry slot moving through southeast
Michigan will shut of bulk of precipitation by around midnight, but
deformation/wrap around snow will be tracking through late Tuesday
night, and light accumulations (1-3") north of I-69 are likely, as
850 mb temps quickly fall into the negative upper single numbers by
12z Wednesday, and into negative lower teens Wednesday morning. -19 C
cold core at 700 MB tracking through the Central Great Lakes likely
will be sufficient for snow showers to impact the rest of the CWA
during Wednesday as well. Regardless of snow, temps may be able to
drop below freezing for the Wednesday morning rush hour across
M-59/I-69 corridors and points north, and will have to watch out for
possible freezing of any leftover wet pavement.
Weak upper ridging and surface high pressure building in from the
Ohio Valley will keep most of Thursday quiet. Cold air parked
overhead will limit highs to the mid to upper 30s for most of the
region, but closer to the Ohio border may make a run at low 40s.
Next chance for snow showers returns Thursday evening and overnight
into Friday as a clipper system dives into the Great Lakes. This
system will bring a reinforcing shot of cold Canadian air and keep
highs much below average, in the 30s, for both Friday and Saturday.
Friday will be gusty and brisk under cold advection and elevated
pressure gradient.
Dry air and expansive high pressure will move into the Great Lakes
by late Friday and lead to a quiet weekend. Lingering thermal
trough...850 mb temps in the negative teens C...will ensure this
period sees the continuation of below normal temps, but some
modification of this airmass with time will allow highs to slowly
creep back toward normal values. A shortwave anticipated to traverse
the central CONUS late Sunday will bring the potential for
precipitation on Monday.
MARINE...
Winds will become northeasterly tonight and strengthen on Tuesday as
low pressure encroaches from the west. Winds will then back to the
north and then northwest Tuesday night into Wednesday as this low
passes through the southern Great Lakes. The onshore flow will lead
to elevated wave heights through the nearshore waters of Lake Huron
with small craft advisory conditions expected from midday Tuesday
into Wednesday. Gale force gusts will also become more likely late
Tuesday into Tuesday night as the deepening low pressure system
passes through the area. Gale force gust potential will persist into
Wednesday as cold and unstable northwest flow surges into the area
in the wake of this low pressure. A Gale Watch has been issued for
parts of Lake Huron.
HYDROLOGY...
Widespread rainfall will spread into the region late tonight and
persist on Tuesday as low pressure crosses the southern Great Lakes.
While overall rainfall averages should range generally between one
half and three quarters of an inch, a few thunderstorms will bring
the potential for locally higher amounts on the order of one inch by
Tuesday evening. Aside from ponding of water within poorly drained
areas, these amounts will not be sufficient to produce any flooding.
Colder air filtering into the region may bring a transition to light
snow Tuesday night and early Wednesday before precipitation ends.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...Gale Watch from Tuesday evening through Wednesday afternoon for
LHZ362-363-421-422-441-462.
Gale Watch from Wednesday morning through Wednesday afternoon for
LHZ463-464.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
AVIATION.....CB
DISCUSSION...SF/TF
MARINE.......DG
HYDROLOGY....DG
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Lincoln IL
733 PM CDT Mon Apr 2 2018
.UPDATE...
Issued at 733 PM CDT Mon Apr 2 2018
After a brief break late last night through this afternoon, the
next weather system currently organizing in the lee of the Rockies
over eastern Colorado is beginning to impact central Illinois
early this evening. 00z/7pm radar imagery showed clusters of
elevated thunderstorms moving across the SE counties...generally
south of I-70. This convection is tied to a developing warm front
that will gradually lift northward into central Illinois later
tonight into Tuesday morning. HRRR has been handing the convective
evolution quite well thus far, so will be following its forecast
closely in the short-term. As such, have raised PoPs to likely
along/south of I-70 where showers/thunder will be ongoing through
the night. Further north, some patchy drizzle/sprinkles have been
observed from time to time, but no measurable precip has developed
yet. This will change as the evening progresses, with all high-
res models showing scattered showers developing northward across
the remainder of the KILX CWA by midnight. The precip will become
widespread across the board overnight, warranting likely to
categorical PoPs at that time. Will need to keep a close eye on
visibilities over the next few hours as fog has developed across
south-central Illinois and is steadily advecting N/NW into the
area. HRRR/Rapid Refresh/NAMNest/GFSLAMP all show fog developing
across the entire CWA by late evening into the overnight hours,
with locally dense fog likely. Do not think fog will become
widespread/dense enough to prompt a Dense Fog Advisory, mainly due
to the prevailing S/SE wind of 5-10 mph and the developing
showers which should help keep the boundary layer mixed. Even
still, areas of fog with significantly reduced visbys at times
will be the rule overnight into Tuesday morning.
&&
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 356 PM CDT Mon Apr 2 2018
Precip is slow to move into the area but clouds have already
arrived over most of the CWA. Fortunately temps have warmed
several degrees or more above freezing. Sunshine and warming temps
have also melted almost all the snow over the area, including
spots where some of the deeper snow fell yesterday and last night.
Also, fortunately, this occurred before the clouds moved in. So,
any precip that occurs will be in the liquid form and am not
expecting any freezing rain. A warm front associated with the
approaching system will bring this over-running precip this
evening and should increase in coverage during the overnight
hours. So, pops will start as a chance this evening and then
increase to likely for eastern and southeastern IL later tonight.
Along with that, some isolated/elevated storms are possible just
north of this front and into the warm sector overnight. As the low
pressure area lifts northeast across the area, showers and
isolated storms will continue during the morning and early
afternoon hours, but mainly in the east and southeast; east and
south of the low track. SPC has part of the CWA in a slight risk,
but with cloudy skies and scattered showers through the morning,
instability will be limited. Shear will be ok, but not great.
However, decent parameters to indicate scattered severe weather is
possible. Appears best chance of svr weather will be afternoon
with best severe type being damaging winds. Cloud cover will hold
heat in tonight and with warming continuing through the night, not
expecting much drop in temps through the night. Temps will be
warmer tomorrow, but based on path of weather system, warmest
temps will be in southeast half of the area, with lower temps to
the northwest...however all still above freezing.
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 356 PM CDT Mon Apr 2 2018
Could be some lingering precip in the north and northeast Tuesday
night as the upper level system rolls by, but dry weather is
expected through Wed night. Then the weather pattern remains
unsettled through the rest of the week and the weekend. Another
chance of precip is coming in for Thur through Thur night with a
rain/snow mix possible late Thur nite. After another dry period
Fri through Sat night, another chance of precip is possible Sun
through Sun night. Temps through the extended period will remain below
normal for April.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 658 PM CDT Mon Apr 2 2018
MVFR ceilings have spread across all of central Illinois early
this evening...with IFR ceilings poised just upstream along/south
of a KIJX to KTAZ line. Based on satellite trends and HRRR
forecasts, think IFR ceilings will develop at all terminals
between 02z and 04z. Scattered showers and thunderstorms are
currently tracking along/south of the I-70 corridor...with
showers expected to develop further northward as the evening
progresses. Have therefore brought predominant SHRA to KSPI/KDEC
by 02-03z...then further northwest to KPIA by around 06z. Once the
low clouds and showers arrive, they will stick around for the
remainder of the 00z TAF period. Winds will initially be from the
SE at 10kt or less tonight...then will gradually veer to the W/SW
and increase markedly on Tuesday. The latest indications suggest
winds will gust 20-30kt after 18z Tue as low pressure tracks into
the Ohio River Valley.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barnes
SHORT TERM...Auten
LONG TERM...Auten
AVIATION...Barnes
Area Forecast Discussion
National Weather Service Key West FL
1018 PM EDT Mon Apr 2 2018
.DISCUSSION...
Under partly cloudy skies with a gentle to moderate mainly
easterly breeze, temperatures in the Florida Keys are in the mid
70s. There are no precipitation echoes on KBYX Doppler radar, just
drifting chaff west of the Marquesas.
The evening local sounding shows the gentle to moderate easterly
winds extend to about 8000 feet, and backed to the northwest
through the mid and upper levels. Moisture has declined noticeably
over the past 24 hours or so, and there is a convectively
resistant layer between 5000 and 7500 feet. Am tempted to remove
any mention of precipitation altogether through the overnight
period, but the latest HRRR solution is bringing a low amplitude
low level impulse westward across the area through the early
morning hours. So, there may be a few light showers associated
with that. But they should be shallow and weak, and a 10 percent
probability of measurable rain will be maintained. No zone update
is planned at this time.
&&
.MARINE...
No change expected on the late evening coastal waters update.
Expect gentle to moderate east, or east to southeast breezes to
continue. No advisories or cautionary headlines for small craft.
&&
.AVIATION...
VFR will prevail at both EYW & MTH terminals. Surface winds will be
less than 10 knots and primarily out of the east. After 03/12Z,
winds will become southeast and FEW to SCT clouds could develop
AOA FL020.
&&
.CLIMATE...
In 1987, after a high of 65F and low of 56F the previous day (the
1st), the low temperature of 48F at Key West International
Airport on the 2nd shattered the cold record for the date. It is
the lowest temperature ever recorded in Key West in the month of
April (with the next-lowest being 54F in 1891), and the next-
latest sub-50F reading ever is 49F on March 04, 1980. 47F on March
03, 1986. Temperature records at Key West date back to 1872.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...None.
&&
$$
Public/Marine/Fire...04
Aviation/Nowcasts....Chesser
Data Collection......Chesser
Visit us on the web at weather.gov/key
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www.facebook.com/nwskeywest
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Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
617 PM CDT Mon Apr 2 2018
.UPDATE...For 00Z Aviation discussion below
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 338 PM CDT Mon Apr 2 2018
Warm advective band has lifted up to along and just north of the
I-94 corridor this afternoon. It`s about as far north as it is
going to go. It has been a bit of an overachiever in the snowfall
intensity department with visibilities getting down to 1/4sm -
1/2sm range in the band. IR imagery shows the cold cloud tops
indicative of the stronger lift moving into WI this afternoon, so
this fits the idea of what we are seeing with the HRRR and other
models that this band will quickly begin to diminish this
afternoon as this stronger lift works east.
Next round of snow moves in with the strong wave that shows up in
water vapor imagery over Montana. We did speed up the arrival of
the snow this evening while also slowing down it`s departure on
Tuesday as this wave will be deepening and taking on a negative
tilt trough the day on Tuesday, resulting in snow lingering longer
than previously forecast. Model agreement is pretty high for snow
amounts Tuesday and changed very little from what we had
overnight, with 6-10" of snow expected from south central MN up
into central WI, this is where we upgraded the watch into a
warning. Don`t think we will need to expand the warning much to
the northwest based on the surface low track. Kansas City to
Kalamazoo, MI is a little too far southeast to pull the higher
snow amounts as far northwest as the core of Twin Cities metro.
.LONG TERM...(Tuesday night through Monday)
Issued at 338 PM CDT Mon Apr 2 2018
Used the blended guidance in the extended, but did lower
temperatures considerably in the extended forecast as the Upper
Midwest will continue to be on the cool side of the thermal
gradient. A few light snow showers Thursday afternoon and evening as
the coldest air moves through. Looking ahead, another band of snow
looks to move across Minnesota and Wisconsin late this weekend. All
three models are in fairly good agreement in the development of this
snow, but the ECMWF is just a few hours slower than the GFS and GEM.
Something to watch as this has the potential to produce several inches
of heavy wet snow.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 618 PM CDT Mon Apr 2 2018
Round 1 of the snowfall has shifted to areas along and north of
Interstate 94, and will primarily affect northern/central sites
with attendant MVFR conditions (KAXN, KSTC, KMSP, KRNH) early
this evening. The next batch spreads from west to east across the
area between 07Z and 11Z, with IFR cigs/vsbys becoming prevalent
for much of the day Tuesday. Winds will also turn to the
north/northwest, with gusts to around 22-25 knots developing.
KMSP...
Another band of snow with MVFR conditions will work into KMSP
from the west around issuance time. Expect this to last for a few
hours, with a brief break in MVFR vsbys until the main round
arrives overnight. East winds gradually back to the northeast for
the morning push, become gusty after 13z, then back to the
northwest by 21Z and remain gusty.
/OUTLOOK FOR KMSP/
Wed...VFR. Wind W at 10G15kts.
Thu...Slight Chc -SN/MVFR. Wind W at 10G20kts.
Fri...Chc MVFR cigs. Wind NW 15G25kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Storm Warning from 1 AM Tuesday to 4 AM CDT Wednesday for
WIZ016-024>028.
Winter Weather Advisory until 1 AM CDT Wednesday for WIZ014-015-
023.
MN...Winter Storm Warning from 1 AM Tuesday to 4 AM CDT Wednesday for
MNZ070-076>078-082>085-091>093.
Winter Weather Advisory until 1 AM CDT Tuesday for MNZ041>045-
047>052-055-057-058.
Winter Weather Advisory until 1 AM CDT Wednesday for MNZ053-
059>063.
Winter Weather Advisory from 1 AM Tuesday to 1 AM CDT Wednesday
for MNZ066>069-075.
Winter Weather Advisory from 1 AM to 7 PM CDT Tuesday for MNZ054-
056-064-065-073-074.
&&
$$
SHORT TERM...MPG
LONG TERM...JRB
AVIATION...LS
Area Forecast Discussion
National Weather Service Charleston WV
1021 PM EDT Mon Apr 2 2018
.SYNOPSIS...
A stationary front will lift northward across the region as a
warm front tonight. A cold front will cross the area Tuesday
night into Wednesday morning. Strong thunderstorms and heavy
rain are possible with this cold front.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 1015 PM Monday...
Taking note of the potential elevated convective elements of the
forecast for the overnight and morning period on Tuesday.
Definitely have stout moisture transport into the middle Ohio
Valley in the low levels, but the best overall instability and
low level convergence will be back to the west over southwestern
Ohio and southeastern Indiana. HRRR is far more aggressive on
the southern extent and coverage of the showers tonight, whereas
the latest NAM run has a steady push of the low level f-gen to
the north through time. In the end, will need to watch for any
counties to receive multiple rounds of showers tonight.
As of 205 PM Monday...
A warm front pushes through the region overnight tonight into
tomorrow morning. Some showers may accompany this front as it
moves through the area. As the front pushes northward tomorrow
it will allow warm southerly air to move into the region.
Temperatures tomorrow will tap out into the 70s across the
lowlands and in the mid to upper 60s in the higher elevations of
thee eastern mountains. Clouds will increase from the west
during the day tomorrow as an approaching cold front will be
knocking on our doorstep by tomorrow late afternoon and evening
tomorrow.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 250 PM Monday...
The aforementioned cold front will begin its march from West to
East across the area at the start of the short term Tuesday
night. Showers and storms will precede the front in the warm
sector with a line or two developing immediately ahead of the
front. Instability is our main limiting factor with the setting
sun; areas toward the West in our SE Ohio/NE Kentucky counties
top out between 700-900 J/kg sfc based CAPE, however bulk shear
on the order of 45-55kts mean storms that do form have the
potential to contain severe- level winds and hail. As of this
hour, the SPC has the eastern boundary of slight risk roughly
along the Ohio River in WV with SE Ohio/NE Kentucky being under
slight risk and the rest of the western lowlands under a
marginal risk of severe storms. In addition to the severe
threat, PWAT up around 1.25" indicates the potential for heavy
rain in storms. There is no widespread flood threat, however
heaviest storms over already saturated grounds will produce
localized rises in creeks and streams and may cause brief bouts
of minor, nuisance-type flooding.
The front exits to the East taking with it heavy rain and storms
during mid- to late-Wednesday-morning. A dry slot works in
briefly before CAA-type shower activity moves back in during the
afternoon and evening. 850mb temps between -6C and -8C during
the evening will allow for remaining rain showers to switch to
snow showers in the higher elevations, though the season, sun
angle, and waning moisture dictate only minor, short-lived
accumulations. High pressure builds from the West to round out
the short term.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 315 PM Monday...
High pressure resides over the area making for a very cold
Thursday morning with NW flow aloft continuing to reinforce the
cold air in place. An upper level short wave, reminiscent of the
more autumnal/wintertime Alberta clipper, brings our next
weather system in at the end of the work week. Models agree on a
cold front extending down from the parent low traversing the
Great Lakes under the clipper entering the area. Timing
differences are abound though - one solution has warm-frontal
precipitation Thursday night with a Friday evening cold front
passage, meanwhile another major long-range model features a
daytime cold front passage Friday and a clean exit by sunset.
Depending on how much cold air is already in place, and
depending on how much cold air is brought down by the front,
snow is possible.
Beyond Friday, models diverge on the movement of the cold front
after passing our area. The boundary may linger at the base of
the long-wave trough across the southern/central Appalachians,
leaving itself open for further development should another short
wave act upon it. This solution would maintain some low-level
PoPs at least across the southern counties. Weakly forced zonal
flow aloft doesn`t leave much to grasp onto weather-wise, so
have chosen to stick with the general blend of models, which
suggests the above solution.
The mean trough finally passes by the end of the weekend and
ushers in a warming trend rain showers possible Sunday night
through Monday.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
As of 720 PM Monday...
MVFR gradually lifting this evening, and reflect that for the
first few hours of the forecast except for BKW where moist SE
flow has brought low ceilings that will maintain themselves
under said flow. Do think they could lift to low end MVFR
however after 03Z in a slight increase in wind velocity.
Given the showers are with a warm front/warm air advection
pattern, will not take sites down to IFR in precipitation
tonight.
Expect SW flow to increase tomorrow in the warm sector with the
cold front on the move towards the area, but beyond the scope of
this forecast.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z WEDNESDAY...
FORECAST CONFIDENCE: Medium.
ALTERNATE SCENARIOS: Timing of improving conditions may vary
this afternoon and evening. Timing of warm front and MVFR
conditions may vary tonight and Tuesday morning.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE TUE 04/03/18
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY L H H H M M M M M M M M
HTS CONSISTENCY H H H H M M M M M M M L
BKW CONSISTENCY L L M L L L L L L L L L
EKN CONSISTENCY H H H L M M M M M M M L
PKB CONSISTENCY M H H H H H H H H H H L
CKB CONSISTENCY M M H H H H H H H H M M
AFTER 00Z WEDNESDAY...
IFR possible Tuesday night into Wednesday in showers and
thunderstorms.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.
&&
$$
SYNOPSIS...JS/MC
NEAR TERM...JS/26
SHORT TERM...MC
LONG TERM...MC
AVIATION...26
Area Forecast Discussion
National Weather Service Shreveport LA
1037 PM CDT Mon Apr 2 2018
.UPDATE...
Tweak pops and weather and beef up winds and gusts for Tuesday.
&&
.DISCUSSION...
Radar continues to show some middeck light showers will may result
in some unmeasurable sprinkles in E TX, SE OK and SW AR overnight.
The HRRR is still showing some early shower or isolated
thunderstorm development toward daybreak with no changes there.
Most of the forecast elements in great shape this evening with no
changes needed. However, we have gone with some higher gusts for
the day ahead than indicated in the previous issuance. Also, made
some wording changes for our expected max gusts in the Lake Wind
Advisory product. /24/
&&
.PREV DISCUSSION... /issued 533 PM CDT Mon Apr 2 2018/
AVIATION...
VFR conditions currently prevail across all terminal locations
this evening. Cu field near 5-6kft will remain scattered through
the evening with mid and high level cloud cover gradually
increasing in coverage across our terminal airspace through the
night. A very strong low level pressure gradient will materialize
overnight which will help to generate an MVFR ceiling deck which
should rapidly move from south to north across the western 2/3rds
of our airspace overnight and into the ELD/MLU terminals near or
shortly after sunrise. Have left out mention of IFR ceilings as
the strength of the gradient and low level wind field should keep
the ceilings just above 1kft but will monitor this as we go
through the night.
Ceilings to gradually rise through the late morning into the
afternoon hours across most locations as we await the ignition of
strong to severe convection to ignite during the afternoon hours
along and ahead of an upper trough and associated sfc cold front.
Have made mention of VCTS most locations between 18z and 22z with
prevailing TSRA across most locations at the very end of this TAF
period.
South winds this evening will increase to 12-16kts sustained
overnight with higher gusts across our NE TX terminal locations.
These winds will continue to increase ahead of the cold front
after sunrise on Tuesday with most locations seeing sustained
winds of 14-18kts with gusts upwards of 30kts. The winds will
begin to shift around to the west and northwest just beyond this
TAF cycle.
13
PREV DISCUSSION... /issued 355 PM CDT Mon Apr 2 2018/
DISCUSSION...
Water vapor imagery shows that our zonal flow aloft over the
region is starting to become ever so southwesterly ahead of an
approaching shortwave. As a result, the weak cold front is
starting to lift back to north, as gusty south winds develop
across the region. Radar imagery shows some light showers trying
to develop in the warm sector over east Texas this afternoon. At
this time believe any rainfall the remainder of this afternoon
will be relatively light. May see a random lightning strike as
well, but not overly impressed as we move into the evening hours.
Believe that our far northern counties will see the threat of
showers through the night tonight, as this system orients itself.
Otherwise, the main forecast concern for this forecast period
continues to be with the threat of severe weather for Tuesday
afternoon and evening, as a more potent cold front moves through
the region. Although some showers and a stray thunderstorm will
to be possible during the morning, expect the primary development
organizing into a squall line during the late afternoon and
evening. At this point in time, believe the primary threat will be
with strong and damaging winds, but cannot rule out large hail or
an isolated tornado as well, as most of the region remains under a
slight risk of severe weather tomorrow.
Drier and cooler conditions will develop behind the cold front for
Tuesday night and Wednesday. Overnight temperatures in our
northern zones will likely fall into the mid 30s, and locally a
few of the colder locations may be flirting with the freezing
mark. At this point in time, do not think we will need a freeze
warning, but we may need to consider a frost advisory for those
northern counties. Daytime highs will also fall to between 8 and
14 degrees below normal on Wednesday. However, temperatures will
warm 3 to 6 degrees each day, with temperatures returning to near
normal by Friday.
Models are hinting at our next decent shot of rain coming late
Thursday night and into Friday. This cold front appears to stall
over the region Friday and Friday night, before slowly pushing out
of the region on Saturday. At this point in time, cannot rule out
severe weather on Friday or Saturday, but it is something we will
need to watch for. Temperatures should fall back below normal for
Saturday. However, warmer and drier conditions should redevelop
for Sunday. The extended models are showing us potentially
getting clipped by another disturbance for Monday, but confidence
in low in this at this time.
Palmer
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 68 79 43 65 / 10 80 70 0
MLU 67 82 44 64 / 10 50 80 0
DEQ 60 72 34 62 / 20 60 20 0
TXK 66 75 38 61 / 10 70 40 0
ELD 67 78 39 63 / 10 70 70 0
TYR 68 77 41 65 / 10 80 40 0
GGG 67 78 42 65 / 10 80 50 0
LFK 68 81 47 68 / 10 80 80 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...Lake Wind Advisory from 7 AM to 4 PM CDT Tuesday for ARZ070>073.
LA...Lake Wind Advisory from 7 AM to 4 PM CDT Tuesday for LAZ001>006-
010>014-017>022.
OK...None.
TX...Lake Wind Advisory from 7 AM to 4 PM CDT Tuesday for TXZ096-097-
108>112-124>126-136>138-149>153-165>167.
&&
$$
24/13/28