Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/27/18
Area Forecast Discussion
National Weather Service Boston/Norton MA
958 PM EDT Mon Mar 26 2018
.SYNOPSIS...
High pressure will bring pleasant afternoons away from the raw /
chilly NE winds along the coast Tuesday. Spotty precipitation
Wednesday and into Thursday. Spring-like temperatures return
Thursday and into Friday before a cold front passes through over
the weekend. On and offshore showers for the end of the week into
Saturday.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
10 pm update...
Tranquil, overnight weather. High pressure against an offshore low.
Pressure gradient persists over SE New England, subsequent near 30-
mph wind gusts along with scattered 2-3 kft cloud decks, otherwise
light winds. Add clear conditions, locations already decoupling,
radiational cooling ongoing, looking at lows dropping down into
the 20s to teens N/W. Per RAP model, scattered H2-3 high cloud /
cirrus by morning round a building mid-upper level ridge into the
region. Such clouds could limit ongoing decoupling prior to sunrise.
Aside, few things to watch: 1.) Cape and Islands NE wind persistence,
2.) marine stratus, and 3.) high cloud from the W. All which would
have implications on overnight 2m temperatures, radiational cooling
processes, and morning lows. An exciting night to say the least.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
Tuesday...
Blocking well downstream of the cutoff S of Nova Scotia, continues
to prevent it from shifting further E with time. Meanwhile secondary
trof continues to push E from the Great Lakes late Tue into Tue
night. This squeezes the foldover ridge significantly limiting
the building due to WAA into it. However, this mid lvl ridging
will be the dominant player through the day on Tue, yielding
mainly dry wx with continued subsidence throughout the day. In
fact aside from some ocean enhanced clouds moving in from the E,
expecting another mainly sunny day until filtered CI spills
over from the W in advance of a sfc-low lvl warm front.
Modest WAA yields a nearly isothermal layer H92 to H85, with after-
noon temps at this lvl approaching +3C. Therefore, expecting highs
in the low-mid 50s in the CT valley, mid 40s to around 50 elsewhere
except E coastal MA, where onshore flow will limit temps to the low
40s.
Tuesday night...
Vertical depth of the isothermal layer continues to build overnight
expanding to between H92 and H7 at least, although there is little
change with actual values, holding near +3C. Overnight diurnal temp
drop-off at the sfc will be key as some locations dip to below the
freezing mark by early AM.
While temps drop, noting gradual saturation through the isothermal
layer and points above, however dwpt depressions near the sfc run
nearly 10C through much of the night. Light overrunning within
this moist layer will be enough to yield light SCT precipitation
moving W-E from NY during the early morning hours. As sfc temps
cool/wetbulb, whether or not they fall below freezing will determine
whether pockets of light FZRA or sleet are observed, but given
the dry layer near the sfc the onset of precipitation will be
slow. Given this uncertainty, will hold off on any headlines for
FZRA risk at this time, but this will have to be monitored as
we approach. Best chance where all of these factors come together
is in NW MA/CT at this time.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Highlights...
* Light precip/ice possible Wednesday morning
* Spring-like weather returns by Thursday into Friday
* On and off showers by the end of the week into the weekend
Overview...
12z guidance is general agreement with the overall flow, however
there are differences when it comes to each shortwave resulting in a
spread in the timing and track of each system. Strong upper level
low will remain anchored over Manitoba/Hudson Bay with high pressure
over Greenland. Broad cyclonic flow will be the overall pattern with
quick moving upper impulses late this week and into the weekend.
Approaching low on Wednesday will try to push a warm front through
on Thursday. Flow turns more zonal, but still an active pattern with
several shortwaves pushing through the flow. This has lead to a low
confidence forecast due to the spread in guidance. Overall appears
that the trend is for an active end of the week into the weekend.
Details...
Wednesday...Moderate confidence.
* Potential for spotty light freezing rain Wednesday morning
Exiting high pressure over the region with a weak wave approaching
from the west. Light precip will move into the CT River Valley
Wednesday morning, once the profile saturates. Precip will struggle
to move eastward as high pressure offshore will keep enough dry air
in place to limit precip chances. Thermals are a bit marginal as a
warm layer moves into the region around 800 mb. If surface
temperatures are at or below 32F in the morning, then the potential
for some spotty freezing rain is possible. Best location is across
the CT river valley, and the east slope of the Berks. Will continue
to evaluate the need for headlines over the next day.
Temperatures on Wednesday will quickly warm by the late morning into
the afternoon. This will change any p-type to all rain. Approaching
surface low across the Midwest will eventually bring widespread
precip to the rest of the region later in the day. However, this
system will be quite weak so only expect light rain showers into the
evening.
Thursday and beyond...Moderate confidence.
Temperatures...
Spring returns to the region as west to southwest flow filters into
the area. High temps will warm above average for the end of March as
warm front tries to push through on Thursday. Feel guidance is to
optimistic and warm front will hang up south of the area. Thus have
lowered Thursday temps a few degrees. On Friday, with approaching
cold front, feel a surge of WAA will occur with the potential for a
few spots reaching into the low 60`s. Behind the cold front,
temperatures will drop back to near seasonable by the weekend into
early next week.
Precipitation...
Mid-level ridge will begin to break down with several waves moving
through the flow as mentioned above. These waves will result in a
few rounds of precip during the period. Spotty light precip is
possible on Thursday, with a heavier round of rainfall possible on
Friday, depending on where the low pressure tracks and the locations
of the cold front. Ensembles continue indicate precip potential on
Saturday with a drying trend into early next week. Because of the
uncertainty kept a slight chc of precip until guidance becomes more
inline.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Tuesday Night/...High Confidence.
Tonight into Tuesday...
VFR except Cape and Islands where SCT-BKN 2-3 kft CIGs persist
along with NE winds gusting up to 30 mph. Diminishing trend into
Tuesday. Otherwise building FEW-SCT high CIGs, light winds.
Tuesday night...
Progressively deteriorating conditions, mainly across W MA/CT
by 12z Wed. CIGS diminish to MVFR or low VFR. -RA (potential
for -FZRA across NW MA early). Winds light and variable, but
gradually trending toward S by Wed morning.
KBOS Terminal...Will monitor potential SCT 2-3 kft MVFR CIGs
through early Tuesday morning.
KBDL Terminal...High confidence in TAF.
Outlook /Tuesday Night through Saturday/...Moderate Confidence.
Wednesday Night: Mainly VFR, with local IFR possible. Chance
SHRA.
Thursday: Mainly VFR, with local MVFR possible. Chance SHRA.
Thursday Night: Mainly VFR, with areas IFR possible. Chance
SHRA.
Friday: VFR. Chance SHRA.
Friday Night: VFR. Slight chance SHRA, slight chance FZRA.
Saturday: VFR. Slight chance SHRA.
Saturday Night: VFR. Breezy.
Sunday: Breezy. Slight chance SHRA.
&&
.MARINE...
Short Term /through Tuesday Night/...
Through Tuesday...
N-NE winds will continue to gust 25 to 30+ kt on the waters
through the overnight hours then gradually dissipate through the
day tomorrow. However, lingering long- period swell from the E
will persist thanks to a storm system S of Nova Scotia. Although
winds will drop below thresholds, the high seas caused by the
swell will force the maintenance of Small Craft Advisories
through Tue.
Tuesday night...
Winds will be gradually shifting to the S but remain below small
craft thresholds. Seas remain elevated due to swell. Small Craft
Advisories will continue due to this risk.
Outlook /Tuesday Night through Saturday/...Moderate Confidence.
Wednesday Night: Winds less than 25 kt. Areas of rough seas.
Chance of rain showers.
Thursday: Winds less than 25 kt. Areas of seas approaching
5 ft. Chance of rain showers.
Thursday Night: Winds less than 25 kt. Seas up to 5 ft. Chance
of rain showers.
Friday: Winds less than 25 kt. Areas of rough seas. Chance of
rain showers.
Friday Night: Winds less than 25 kt. Local rough seas. Slight
chance of rain showers.
Saturday: Winds less than 25 kt. Seas locally approaching 5 ft.
Slight chance of rain showers.
Saturday Night through Sunday: Winds less than 25 kt. Areas of
seas approaching 5 ft.
&&
.EQUIPMENT...
Due to our move to the new forecast office in Norton, MA, we
are still trying to resolve some communication issues. The
following NOAA Weather Radio transmitter is back on the air...
Somers, CT transmitter........WXJ41.....162.475 MHz
However, the following NOAA Weather Radio transmitters are not
yet on the air...
Johnston, RI transmitter......WXJ39.....162.400 MHz
Gloucester, MA transmitter....WNG574....162.425 MHz
Blue Hill, MA transmitter.....KHB35.....162.475 MHz
Hyannis, MA transmitter.......KEC73.....162.550 MHz
Paxton, MA transmitter........WXL93.....162.550 MHz
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 AM EDT Wednesday for ANZ232-235-
237-250-251-254>256.
Small Craft Advisory until 11 AM EDT Tuesday for ANZ231-233-
234.
&&
$$
SYNOPSIS...Doody/Dunten
NEAR TERM...Doody/Dunten/Sipprell
SHORT TERM...Doody
LONG TERM...Dunten
AVIATION...Doody/Dunten
MARINE...Doody/Dunten
EQUIPMENT...WFO BOX Staff
Area Forecast Discussion
National Weather Service State College PA
1118 PM EDT Mon Mar 26 2018
.SYNOPSIS...
A ridge of high pressure over Pennsylvania will push off the
east coast by Tuesday, as a shortwave tracks east across the
Great Lakes. A deepening upper trough and associated surface low
will sweep through the region late in the week.
&&
.NEAR TERM /UNTIL 10 AM TUESDAY MORNING/...
Will continue to leave mention of ZR in for the morning (post-
sunrise) hours. The daylight/heating and SSE wind are the wild
cards, as temps should be below freezing in most places over the
Wrn half of the area around sunrise. The late March sun should
warm up the surfaces quickly even if the air is still below fzg
by mid morning. But, it is still worth mentioning, but not yet
worth an advy. While a few sleet pellets are also possible, have
left out mentions for now, as the mention of all those p-types
could make for an ominous forecast - when there is a pretty low
threat of freezing/frozen pcpn - and only for a short time after
rush hour in most places.
Prev...
Thin high clouds are moving in and will slowly spread across the
rest of the area tonight as they thicken up. Timing on latest
mdl runs suggests that no precip gets to the CWA until after
sunrise, and perhaps not until closer to 10-11AM. So, the threat
for ZR is pretty low, especially overnight where PoPs have been
set to nil.
Prev...
Earlier shallow cumulus has entrained nicely leaving sunny skies
throughout this afternoon. Temperatures have moderated a few
degrees from yesterday with readings ranging through the 40s.
It will be clear with light winds to start tonight providing
favorable conditions for radiational cooling, especially over
eastern portions. Kept mins a bit below guidance for this.
Across the west, clouds increase across the west and central,
and there`s still an outside chance at some light shower
activity reaching into my western zones before sunrise, which
would produce patchy freezing rain if it did so. Think the
increasing clouds and breeze will keep reading slightly above
guidance across the west, and that incoming moisture will have
dry air to overcome before precip arrives, so think precip will
hold off in most areas until well after 12z. Consensus among
surrounding offices was to hold off on any headlines and
strongly concur at this time.
&&
.SHORT TERM /10 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
Increasing clouds and warm advection in advance of Great Lakes
shortwave will bring showers into the western half of central
PA by afternoon. Surface ridge wedged east of the Appalachians
and associated cold air damming may hold in just enough cold air
for a brief period of -fzra across the Alleghenies if precip
arrives early enough Tuesday morning. Confidence still too low
on this, and think most areas warm above freezing before precip
arrives. Model soundings and ensemble plume diagrams indicate
any threat of icing should end by late morning. Have placed the
highest POPs of 80-90 pct across the northwest counties for the
afternoon hours, where low level jet focuses best moisture and
lift. Southeast has only a slight chance of rain by late
afternoon.
Cold air damming and increasing clouds/moisture will keep temps
slightly cooler than guidance, with most areas ranging from the
upper 30s north to the lower 40s south.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
As was the case in late February...a southwest flow of air
works into the area on Wednesday. Temperatures will climb
to above normal for a few days.
Main issue is where the cold front stalls and if one will
get a weak low on the front...or a bigger storm for late
Friday.
12Z EC has backed off on such a deep system from the 00Z
run...but I did up pops a little Friday night. Main change was
to split the weather group in two for Saturday. As noted by
earlier shifts...I did not want to go too high with POPS in any
one time group.
For day 7 weighted most of the fields by the superblend.
Prior to Friday night...main change was to lower temperatures
a little after Wednesday...given lack of strong low level
flow...and hints that cold front could stall or sag south of
central PA.
Overall...there has a lot of model spread for late in the week
the last few days.
Easter looks dry but on the cool side.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
VFR will prevail overnight.
The HRRR still shows the rain or wintry mix overspreading my
western zones between 7-9 am.
Latest timing suggests lowering conditions begin to develop mid
to late morning over the west, and spread east during the
afternoon.
The weather is expected to remain unsettled through the end of
the week.
Outlook...
Tue Wed...Restrictions likely with scattered rain showers.
Thu-Fri...Widespread MVFR/IFR with rain or showers.
Sat...Psbl MVFR north.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...DeVoir
NEAR TERM...Dangelo/DeVoir
SHORT TERM...DeVoir
LONG TERM...Martin
AVIATION...La Corte
Area Forecast Discussion
National Weather Service Cheyenne WY
547 PM MDT Mon Mar 26 2018
.SHORT TERM...(This evening through Tuesday night)
Issued at 230 PM MDT Mon Mar 26 2018
Just a few rain/snow showers occurring across the CWA this
afternoon in association with an upper trough draped ne-sw
across Wy. This trough will weaken slowly overnight as energy
gets pulled southward to an upper low over AZ so expect pcpn to
end and skies to gradually clear overnight. Tuesday will be mild
and dry under mostly sunny skies with the upper flow becoming
established out of the northwest. The next upper trough will begin
to approach the CWA Tuesday night bringing a cool front into the
CWA late and possibly a few snow showers to far northwest parts as
well.
.LONG TERM...(Wednesday through Monday)
Issued at 230 PM MDT Mon Mar 26 2018
Cool and unsettled weather across the CWA Weds into Thursday as
broad upper cyclonic flow sets up across much of North America.
Will have to watch for potential for some decent snow Weds night
into Thursday across parts of southeast Wy as some jet energy
will overlay surface upslope flow for a time. Some accumulating
snow looks likely especially over higher terrain. Clearing out
Thursday night with the passage of a shortwave in the flow with
mainly dry and mild weather returning Friday into Saturday. Next
system approaches later Saturday with the EC showing a pretty
strong cold front passing across by late Saturday and a chilly day
Sunday with some snow. GFS similar but about a day faster. For now
will favor the slower EC solution as it has better support with
other models.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 545 PM MDT Mon Mar 26 2018
Expect snowshowers to end after sunset this evening. Mainly VFR
across southeast Wyoming. Need to watch the Panhandle as latest
HRRR guidance suggesting IFR conditions in the northern Panhandle
tonight.
&&
.FIRE WEATHER...
Issued at 230 PM MDT Mon Mar 26 2018
Cool to mild temperatures expected through the period. Some
wetting precipitation looks a good bet across much of the area
Weds afternoon into Thursday and again towards Sunday. these
factors will keep fire weather concerns low for the foreseeable
future.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...RE
LONG TERM...RE
AVIATION...GCC
FIRE WEATHER...RE
Area Forecast Discussion
National Weather Service Duluth MN
905 PM CDT Mon Mar 26 2018
.UPDATE...
Issued at 905 PM CDT Mon Mar 26 2018
Decided to issue a Winter Weather Advisory for much of northwest
Wisconsin due to recent reports of 2 to 3 inches with another 1 to
possibly 3 inches still possible through about midnight or 1 am.
Some freezing rain/drizzle will also be possible.
UPDATE Issued at 819 PM CDT Mon Mar 26 2018
Snow has diminished or ended across western portions of the
Northland and continued most other areas. Temperatures were still
warm enough for rain or a mix over parts of northern Wisconsin but
more snow than rain was occurring as of 01Z. Latest radar showed
moderate to at times heavy snow moving across far eastern
Minnesota into northwest Wisconsin. Surface temperatures have been
a bit colder than earlier forecast and we adjusted them down
leading to more snow across northwest Wisconsin. Snow amounts over
northwest Wisconsin will range from 1 to 4 inches with isolated
higher amounts expected as an area of FGEN forcing moves through
this evening. A spotter in northern Douglas County had just under
an inch as of 740 pm and another spotter near Hayward had around
1.5 inches.
No changes to the Winter Weather Advisory are planned at this
time.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 317 PM CDT Mon Mar 26 2018
The Northland can continue to expect a wintry mixture of snow,
rain, and freezing rain through this evening. A band of snow was
dropping snow across much of central and north-central Minnesota,
and along the Canadian border of northeast Minnesota, as of the
middle of this afternoon. This band was caused by a mid-level
frontogenetical band associated with low pressure in the Great
Plains, as well as weak-moderate large-scale forcing for ascent
from approaching upper-level low pressure from the west. This
band is expected to shift west through the Northland this evening,
and a shortwave lifting northeast into the southern forecast area
will quickly fill in an area of snow and rain into MN/WI border
region late this afternoon and early this evening. Models are
probably underestimating snow from this latter feature because of
not sufficiently producing cold enough surface temperatures which
should happen with the dynamic cooling from this next wave of
higher precipitation rates. The models are likely producing too
much rain, such as for the Interstate 35 corridor in Pine County
and parts of northwest WI. Therefore, had too some manual editing
to bring down surface temperatures faster than the models, which
gives those areas 1 to 3 inches of snow through this evening. Much
of the rest of Minnesota can expect another 1 to 3 inches through
this evening as from the frontogenetical band and forcing. There
could also be a period of light freezing rain in the wake of the
departing deeper moisture and precipitation this evening,
potentially resulting in a light glaze on roads and surfaces. The
snow will taper off from west to east later this evening, ending
by around midnight. Snowfall totals, including what fell earlier
today, should be about 3 to 6 inches across much of central and
northeast MN, and about 1 to 3 inches in northwest WI. The
greatest snowfall, of about to around 7 inches, is expected around
and north of the Iron Range.
Drier air will filter into the region with west flow later tonight
and Wednesday in the wake of tonight`s passing low pressure.
Temperatures will drop into the middle 20s by early Tuesday. While
there will be some clouds in the morning, the afternoon looks
sunny with warmer, mountain-modified air moving from the west.
Highs should be at least in the middle to upper 40s, but lower
50s are possible.
.LONG TERM...(Tuesday night through Monday)
Issued at 317 PM CDT Mon Mar 26 2018
High pressure will remain in control for much of Tuesday night,
but the next system will already start to move into the northwest
part of the region later in the night. Low pressure moving across
south central Canada will drag a cold front across Minnesota and
western Wisconsin on Wednesday. The better chance of precipitation
with this system appears to be west of our area, with a general
decrease in precipitation as it moves eastward. High pressure and
cooler air will then spread into the region Wednesday night and
Thursday, with another cold front dropping into the region on
Friday and Friday night. The models begin to show some pretty
dramatic differences by Friday, with the GFS bringing considerable
precipitation to the region on Friday night and early Saturday.
The ECMWF shows high pressure over the region at that time, with
precipitation moving through on Saturday and Saturday evening.
Definitely some timing issues with regard to a potential system
late this week and early this weekend. At this point, we will
generally carry chance POP`s from later this week into the
weekend, with a nod given to the ECMWF timing. Highs on Wednesday
will range from around 40 at KINL to the lower 50s in Price
County. By Thursday, daytime highs should be limited to the 30s
for most areas. Friday and Saturday will be the coolest days of
the long term period, with highs ranging from the mid 20s in the
north to the mid 30s in the south. Overnight low temperatures
later in the week could actually fall below zero in the north, as
below normal temperatures persist.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 641 PM CDT Mon Mar 26 2018
An area of low pressure passing through the region has caused
widespread snow and some rain across the Northland as of early
evening. Conditions varied from VLIFR to MVFR over much of
northern Minnesota with some VFR conditions still occurring over
parts of northern Wisconsin. The precipitation will diminish or
end from west to east tonight and the visibility had already
reached 10SM at KXVG and KPWC. As the main area of precipitation
moves off, some drizzle or freezing drizzle and fog will be
possible.
Confidence in how quickly the clouds will diminish on Tuesday is
lower than average. The latest RAP suggests clearing at KBRD mid
to late morning and not until afternoon for other areas. Timing of
the clearing will be refined overnight.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 28 44 26 44 / 100 0 0 20
INL 26 46 29 41 / 90 0 30 40
BRD 27 44 28 44 / 90 0 0 20
HYR 29 46 23 50 / 100 0 0 10
ASX 30 46 26 49 / 100 10 0 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory until midnight CDT tonight for
WIZ001>004-006>008.
MN...Winter Weather Advisory until 10 PM CDT this evening for MNZ010-
018-025-026-033>036-038.
Winter Weather Advisory until midnight CDT tonight for MNZ011-
012-019-020-037.
LS...None.
&&
$$
UPDATE...Melde
SHORT TERM...Grochocinski
LONG TERM...DAP
AVIATION...Melde
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1022 PM CDT Mon Mar 26 2018
.EVENING UPDATE...
Went ahead and lowered PoPs for the everywhere but the westernmost
extent of the CWA per the latest suite of hi-res model runs. There
still exists a low chance for some isolated development from Del Rio
west but per the 00Z KDRT sounding, capping continues with -45 CINH
present although plenty of elevated CAPE remains. Thus, believe the
best opportunity for development will have to come from outflow
boundaries pushing into Val Verde. If they do, large hail and
damaging winds will be the main concern as over 3000 joules of CAPE
are shown on the 00Z sounding as well as DCAPE of over 1100 are
present. However, as these cells move east (if they even develop),
they`d be moving into an increasingly stable environment and should
fall apart as they approach the Hill Country.
&&
.PREV DISCUSSION... /ISSUED 627 PM CDT Mon Mar 26 2018/
AVIATION...
Initial focus for the TAF period will be this evening for KDRT.
Latest runs of the HRRR show the possibility of some thunderstorm
initiation just north of the terminal late this evening associated
with dryline activity. Will show VCTS for the evening hours there to
account for this threat and amend as necessary through the early
evening hours. For the I35 sites, thunderstorm activity will likely
hold off until at least tomorrow afternoon, but scattered light rain
showers will be possible in the morning hours as activity streams
northward. A larger complex of thunderstorms should develop southwest
of the I35 sites in the evening hours tomorrow and will move
northeast into the San Antonio terminals around 3-5z and into AUS a
couple hours later. Will show prevailing thunder for KSAT in its
extended 30 hour portion of the TAF.
Ceilings are VFR at the moment but will lower to MVFR later this
evening and remain MVFR through the early afternoon hours tomorrow.
Could see some possible IFR ceilings for DRT around daybreak.
PREV DISCUSSION... /ISSUED 317 PM CDT Mon Mar 26 2018/
SHORT TERM (Today through Tuesday)...
Main hazard highlights will focus on three hazard windows in the
short term period:
1) Conditional risk of isolated strong to severe storms this evening
across northwest Val Verde County - Low to Moderate confidence.
2) Conditional risk of isolated strong to marginally severe
thunderstorms Tuesday afternoon across Central Texas - Low to Medium
confidence.
3) Late Tuesday night through the day on Wednesday with multiple
rounds of strong to severe thunderstorms and pockets of localized
heavy rain - Medium to High confidence of occurrence.
Main Message:
- 1-2 inches of rainfall appears likely from late Tuesday through
Wednesday. Some localized 3-4 inch amounts can`t be ruled out if
heavier thunderstorms train over the same areas.
- Large hail and localized 40-60 mph wind gusts could occur with the
strong to severe thunderstorms. SPC has northwest Val Verde County
in a Marginal risk for severe storms this evening. The Day 2
Slight risk covers much of the CWA and the Day 3 Slight Risk
southeast areas of the CWA.
- Despite the localized heavy rainfall likelihood, widespread flash
flooding is not expected at this time given the recent dry
conditions, however isolated minor flooding can`t be ruled out.
Storms have developed across the Big Country of Texas this afternoon
along the dry line and latest GOES-16 visible imagery indicates
developing CU along the dryline trailing to the southwest toward the
Big Bend. A Severe Thunderstorm Watch was recently issue for this
area by SPC. Stratus is beginning to accelerate scattering out across
Val Verde County and should eventually see de-stabilization in this
area by evening as dry line approaches. Latest runs of HRRR and
ARW/NMM and NAM12 and GFS indicating convection reaching northwest
Val Verde county between 03Z-06Z. Forecast sounding indicate around
1500-2000 J/KG of MUCAPE as well as effective bulk shear values of
around 60 kts. This should be supportive of a few strong to severe
storms across northwest Val Verde county before CIN sets in. After
06Z convective inhibition rabidly increases and a weakening trend
should take place in convection as it expands northeast through
portions of the Hill Country. Farther east, isolated streamer showers
should develop beneath the cap across the eastern Hill Country and
near and east of I-35 overnight.
Cap should hold through the morning hours on Tuesday. Instability
should grow Tuesday afternoon to near 1500-2000 J/kg across Central
Texas and the northern Hill Country where the dryline will shift
slightly east. If the capping inversion weakens enough, there will be
a conditional risk of strong to marginally severe thunderstorms
across far northern ares of the CWA Tuesday afternoon as deep layer
shear will be 50-60 knots.
Primary event will focus on late Tuesday evening into Wednesday.
Models for several runs have been keying in on convective development
taking place 03Z-06Z Wednesday across portions of the Rio Grande
Plains and Winter Garden region and expanding quickly east and
northeast through the Hill Country and I-35 corridor. This is in
response to height falls ahead of a strong ejecting shortwave
impulse. PWATs are progged to climb to around 1.4-1.7 inches by this
time, near record values for this time of year. Models indicate
increased divergence aloft as 110 kt 300mb jet streak noses into
the region, and deep omega values spreading northeast through the
area. Upwards of 1500 J/Kg could still be present in this environment
and bulk shear values of 60-80 kts will support strong to severe
storms while a cold front shifts south and merges with the dryline.
As forecast soundings becoming increasingly moist adiabatic
overnight and into Wednesday morning the threat may transitions to
more of a localized heavy rainfall threat, although strong storms
still possible overnight.
The thunderstorm evolution into Wednesday afternoon remains
difficult to pin down. It will likely be dependent on how progressive
and widespread showers and storms are in the morning that either
undercut the warm sector with rain cooled outflows or if the
front/dryline remain farther northwest and allow for a supportive
warm and unstable sector to develop for additional thunderstorm
development.
GFS and ECMWF remain more progressive Wednesday night into early
Thursday morning with precipitation chances ending west to east than
the Canadian. Have continued with this thinking.
LONG TERM (Tuesday Night through Sunday)...
Cooler and drier air will shift into the region Thursday and Friday.
A return flow will setup Saturday and strengthen through the
weekend, becoming breezy at times and producing warmer temperatures.
The ECMWF and Canadian continue to indicate a frontal passage Monday
and disturbance aloft producing a chance for precipitation. The GFS
is farther north with the front but does show a disturbance in the
southwest flow aloft generating precipitation over the region Monday.
Given a Day 7 forecast we will at this time just introduce a 20 PoP.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 69 79 66 75 58 / 20 50 90 80 30
Austin Bergstrom Intl Airport 69 80 66 74 58 / 20 40 90 80 40
New Braunfels Muni Airport 69 79 67 76 58 / 20 30 90 80 40
Burnet Muni Airport 67 75 62 72 53 / 30 60 90 80 30
Del Rio Intl Airport 67 83 64 83 54 / 40 30 60 20 10
Georgetown Muni Airport 68 78 63 73 55 / 20 50 90 80 30
Hondo Muni Airport 69 82 66 80 55 / 20 40 90 70 20
San Marcos Muni Airport 69 80 66 75 58 / 20 40 90 80 40
La Grange - Fayette Regional 70 83 70 77 61 / 20 40 70 80 60
San Antonio Intl Airport 69 80 66 78 59 / 20 30 90 80 30
Stinson Muni Airport 70 81 68 78 59 / 20 30 90 80 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Mesoscale/Aviation...Hampshire
Synoptic/Grids...TB3
Area Forecast Discussion
National Weather Service Wichita KS
913 PM CDT Mon Mar 26 2018
.UPDATE...
Issued at 912 PM CDT Mon Mar 26 2018
Cold frontal boundary continues to make slow progress across the
Flint Hills at this time. Front is currently located from KWLD to
KEMP. Low level moisture transport currently is ahead or to the SE of
the front, but mainly parallel to the boundary, with light off and
on showers continuing for most areas east of the Turnpike, or along
or just ahead of the front. Most of the convection ahead of the
front is staying well to the SE of the forecast area over central
OK. Latest RAP data seems to support this with most of the
instability, including most of the elevated instability staying
mainly to the southeast of the forecast area as the front pushes
southeast into NE OK. The only exception being extreme SE KS, where
convergence along the front may lead to a few stray storms. Latest
RAP and hi-rez models keep most of the better moisture transport and
any instability in a SW to NE fashion over OK, which would keep it
ahead of the main frontal boundary. So expect most of the heaviest
rains to stay to the SE of the forecast area. Still think some weak
moisture transport will continue, the off and on, showers for areas
along or over the top of the front, for most of southern KS
overnight, but think the chances of hearing any rumbles of thunder
to the north of the front are diminishing. So will send out an
update and remove most of the thunder mention for most areas west of
the KS Turnpike.
Low level drier air continues to try and scour out the fog to the
north-northwest of the front. Still think some patchy fog will
linger where the post frontal light showers will be located. But
most visibilities will stay in the 3 to 5sm range.
Ketcham
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 327 PM CDT Mon Mar 26 2018
Near term concern is convective trends early this evening, then
the ebb and flow of precip chances through mid-week. Satellite at
mid-afternoon was showing breaks in the clouds just south of the
border in north central Oklahoma. Additional heating through late
afternoon along the southward sagging surface front should yield
a narrow ribbon of MLCAPE of around 1000 j/kg along the KS/OK
border to the S-SE of metro Wichita. This in the presence of
strong bulk shear may support a few strong/marginally severe
storms during the early evening hours. Additional lift north of
the front is expected to promote some elevated showers/isolated
storms across southern Kansas later this evening/overnight. Precip
chances will linger through much of Tuesday across southeast
Kansas while gradually dwindling across central Kansas. The upper
trof/low in the split flow regime across the southwest CONUS will
gradually weaken/fill by mid-week as successively strong trofs
within the northern stream absorb the southern feature across the
central CONUS by Wednesday night/Thursday. Slight to modest precip
chances could return as this occurs with the next frontal
passage, though QPF looks relatively light.
Darmofal
.LONG TERM...(Friday through Monday)
Issued at 327 PM CDT Mon Mar 26 2018
Rather low confidence in the medium range as we head toward and
through the weekend with a lot of spread in the operational ECMWF
and GFS and ensemble members. This looks to affect the timing of
potentially colder air advecting south across the Kansas Plains.
The GFS would support the faster onset on Saturday, though delayed
by about 24hrs by the ECMWF. The precip chances associated with
front do not look overly impressive, though the air could become
marginally cold enough for a light wintry mix across central
Kansas. Expecting a lot could change in the coming days with
respect to the weekend forecast, though it appears any weather
impacts will be minimal for now.
KED
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 659 PM CDT Mon Mar 26 2018
MVFR to IFR/LIFR aviation conditions will be common across most of
the forecast area overnight into early Tue, as a cold front makes
slow progress into the Flint Hills and SE KS. IFR/LIFR CIGS will be
common along or a few hours behind the front, currently located
along the KS Turnpike. Along or ahead of the front scattered showers
will lead to CIGS a little better in the MVFR range. Some drier air
in the low layers, will lead to a gradual improvement in the CIGS
across central KS to MVFR for the overnight hours. Could even see
this drier air try to push into south central KS as well, with cigs
improving some to MVFR as another round of showers moves across
south central KS.
Could see some VCTS over SE KS where the cold front will still be
located with some elevated instability. But think the heavier
SHRA/TSRA will stay to the SE of the KCNU taf site, so will only go
with VCTS.
Ketcham
&&
.FIRE WEATHER...
Issued at 327 PM CDT Mon Mar 26 2018
Periodic chances for additional rain and moderate daytime
humidity levels will keep the fire danger low this week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 43 49 36 63 / 60 60 10 10
Hutchinson 40 49 34 64 / 40 50 10 10
Newton 40 48 35 62 / 40 50 10 10
ElDorado 43 48 36 62 / 60 70 10 10
Winfield-KWLD 46 50 38 62 / 70 80 20 20
Russell 36 52 32 67 / 10 20 10 0
Great Bend 37 51 32 66 / 30 30 10 0
Salina 38 52 34 66 / 20 20 10 0
McPherson 39 50 34 64 / 30 40 10 0
Coffeyville 51 52 40 60 / 90 90 30 20
Chanute 47 49 38 61 / 80 90 30 10
Iola 46 49 37 61 / 90 90 20 10
Parsons-KPPF 50 50 39 61 / 90 90 30 20
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Ketcham
SHORT TERM...KED
LONG TERM...KED
AVIATION...Ketcham
FIRE WEATHER...KED
Area Forecast Discussion
National Weather Service Wilmington OH
1007 PM EDT Mon Mar 26 2018
.SYNOPSIS...
As southerly winds develop across the southeastern states and
into the Ohio Valley, occasional chances for rain will increase
over the next several days. High pressure is expected to bring
drier conditions for Friday.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Area of light showers in lifting through ern IN into wrn OH and
nrn KY. This is a couple of hours quicker than thought earlier.
This band should work northeast through the region over the next
few hours. QPF should only be a few hundredths of an inch.
A second area develops in IL and IN after 06Z and builds into
nw OH by 12Z. This band will continue a little heavier QPF, but
not enough to cause any flooding issues.
Temperatures will only drop a few degrees overnight, or will
remain steady. Lows will range from the lower 40s in the no to
the upper 40s in the sw.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
The upper level pattern over the next several days -- beginning
on Tuesday -- will feature ridging over the southeastern CONUS
and troughing over the north-central CONUS. A broad trough in
surface pressure is expected to develop in between these
features, running roughly from Texas through the Great Lakes,
with frontogenesis occurring as the theta-e gradient becomes
well established within this slow-moving (if not stationary)
frontal zone. In a favorable feed of gulf moisture, with
precipitable water values getting up to around an inch and a
quarter, there will be several rounds of rainfall across the
region during the next few days.
The first will occur from early to mid morning on Tuesday, as
convergence at the nose of an 850mb wind max will help to force
an area of moderate to possibly heavy rain showers. There is
even the potential for some thunder, as models suggest some weak
elevated instability (lifted from 850mb) moving through the
Miami Valley and into central Ohio in the 10Z-15Z time frame
Tuesday morning. This signal is also being picked up on WRF-ARW
and HRRR projections. There may be a period during the afternoon
where showers become more scattered and light in nature, but the
front will be shifting southward going into Tuesday night, with
near-surface convergence and upper divergence will combine to
force another round of showers. For these two more favorable
time periods, PoPs were put in the categorical range, with
100-percent chances expected for much of the CWA especially
Tuesday evening into the night.
Though this period sets up to be rather wet, widespread rainfall
forecasts of an inch (or maybe two if you go out through the
rest of the forecast beyond Tuesday) do not suggest that
flooding will be a significant concern. The band of snow from a
few days ago was considered, but much of this has already
melted, especially given the dry conditions observed Sunday. It
appears that any flooding concerns will probably be localized,
perhaps if convective elements Tuesday morning line up in a
favorable orientation to the flow. While not out of the
question, the WRF-ARW and HRRR runs mentioned earlier would
suggest this potential is higher over parts of Illinois and
Indiana than it is in the ILN CWA.
Though the amount of boundary layer mixing in the moistening
environment is somewhat unclear, there will be the potential for
some 25-30 knot southerly wind gusts on Tuesday afternoon.
Despite the rain and clouds, the warm advection pattern will
allow temperatures to easily reach the middle to upper 50s on
Tuesday -- possibly even into the lower 60s in northern
Kentucky. There should not be much movement on temperatures on
Tuesday night, with fairly steady values in the 06Z-12Z time
frame, and min temps generally in the lower to mid 50s. If the
front is able to clear through the northern ILN counties before
the night is up, temperatures will drop into the upper 40s
there.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
A cold front will be oriented sw-ne through the region on Wednesday
with an area of showers moving southeast during the day. While nw
cwa should see rain end during the morning, southwest flow aloft
will permit a continued stream of disturbances to cross over the
Ohio Valley later in the day and overnight, necessitating some
chance of showers through Thursday night.
Forecast models maintain divergent solutions Friday onwards. The
mean longwave trough over the central U.S. will determine the
sensible weather at the surface for the extended. GFS is quick to
push it through and has a westerly flow set up over the conus by 0z
Saturday. European is
Capped any precip chance beyond Friday at 50% given the polar
opposites of the model solutions starting then. While some snow may
mix in on Friday night if the European is correct, felt that this
would be an outlier forecast and a warmer solution should be leaned
towards. 1000-850 thicknesses are barely supportive of the snow mix
as well, helping the decision to keep any precip rain during this
time.
Temps will be at or slightly above normal on Wed and Thurs and then
drop down to just below climatological norms for the remainder of
the forecast. Overnight lows will start out above normal Wed night
and Thurs night, then drop below normal for the weekend and trend
back to at or above normal early next week.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
H5 vort max lifting up the Ohio Valley is pushing an area of
showers towards the tafs. Consensus of latest mesoscale models
has the leading edge timed to CVG/LUK around 03Z and CMH/LCK
around 06Z. Based on radar and models it looks to affect each
taf site for about 3 hours. Kept prevailing conditions with
this area VFR, but will monitor it in case vsbys and possibly
cigs drop to MVFR.
After this initial shot of showers go by, models drop ceilings
to MVFR. They should remain MVFR for the rest of the period.
Models bring in a steadier area of rain late tonight north of
KDAY. They have a spread in their solutions as to exactly how
far south this area will drop. Brought a few hours of TEMPO
MVFR vsbys in the morning to the nrn TAFs, before going VCSH
for the afternoon hours.
Winds on Tuesday will turn to the south and become gusty
up to 20-25 kts.
OUTLOOK...MVFR ceilings and visibilities will be possible at
times into early Wednesday morning. MVFR ceilings may continue
through Thursday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Hatzos
NEAR TERM...Sites
SHORT TERM...Hatzos
LONG TERM...Franks
AVIATION...Sites
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1036 PM EDT Mon Mar 26 2018
.UPDATE...
Issued at 1036 PM EDT MON MAR 26 2018
There are portion of the far east that remain mostly clear this
evening and this has lead to some adjustments to temperatures to
handle this idea better. Otherwise, a weaker upper level front is
progressing eastward this evening and rain showers continue to
slowly work north and east. Updated POPs to better match the
trends and felt like the HRRR TL had the best idea to lean toward
overall. Also opted to make more minor updates to the grids to
align better with the latest obs.
UPDATE Issued at 739 PM EDT MON MAR 26 2018
Late afternoon satellite pictures did show some clearing in the
east and this did allow temperatures to remain warmer this
afternoon and early evening. This is likely being aided by
downslope flow coming across the higher terrain. Given this did
lower temperatures some in the far east, but think the clouds
will help to mitigate these locations dropping too quickly
through the evening and overnight. A 850mb front will progress
closer to the region through the evening and we have been tracking
some showers and isolated thunderstorms across western and
central Kentucky. The best chances of showers will generally be
north of the Hal Rogers Parkway, but the downslope flow could
certainly eat away at some of the available moisture. Otherwise
only minor adjustments were needed to deal with the latest obs and
trends.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 313 PM EDT MON MAR 26 2018
Thinning clouds and some downsloping have allowed temperatures
over the central part of the forecast area to rise a little higher
than originally expected. As a warm front approaches from the west
clouds will thicken back up tonight and there will be a chance for
showers. As the front lifts across the area on Tuesday the shower
chance will end from south to north. A better chance of showers
will occur Tuesday night as low pressure moves from the mid MS
valley into the OH valley and a cold front approaches the area.
Temperatures will be above normal from tonight through Tuesday
night, as south to southwest flow becomes established across the
area.
.LONG TERM...(Wednesday through Monday)
Issued at 405 PM EDT MON MAR 26 2018
An amplified long wave pattern will be in place across the CONUS
for the latter half of the work week. This will transition to
zonal flow for the weekend, with further amplification into early
next week. A broad trough will gradually move from the
Mississippi Valley to the Eastern Seaboard. This will allow a
surface cold front, with multiple waves of low pressure riding up
along it, to bring soaking rains to the Ohio and Tennessee valleys
Wednesday through Thursday. At least small chances of
precipitation will linger across the region into the weekend and
especially next week, as the pattern turns more progressive;
however, there is lower confidence in the details this far out.
Widespread showers will move in from the northwest Wednesday into
Wednesday evening. The boundary will stall out across our area,
with another more significant surge of moisture and lift moving in
late Wednesday night and continuing through Thursday. QPF
totals continue to vary from run to run, but in general, have come
down somewhat across our area, especially the ECMWF. Deeper
convection to our south will likely be a factor, and have
continued to generalize the heavy rainfall threat in the HWO.
Forecast confidence continues to be low for the latter half of the
extended period, given the timing and evolution issues regarding
the smaller scale features. In general, the first half of the
weekend looks to be drier, and then precipitation chances ramp up
into Monday. Overall, temperatures will average near to slightly
above normal through the period, with a minor cool down into the
weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 729 PM EDT MON MAR 26 2018
VFR conditions will continue this TAF cycle as much of the lower
clouds remains well to our west. A 850mb front is moving across
the center part of Kentucky, with a line of showers and isolated
thunderstorms moving northeast. The best chances of seeing a rain
shower will be across northern parts of the eastern Kentucky and
therefore did add -SHRA to JKL, SJS, and SYM. The only issue will
be the downslope flow could eat away at some of the moisture as
it tries to progress into the region. Given the weak winds at the
surface and an increased LLJ tonight will most likely lead to
increased wind shear across the region. Given these factors did
keep LLWS mentioned in the TAFs later this evening into the
overnight. We then see some decent mixing potential for Tuesday
afternoon and this will provide the potential for 15 to 20 knot
wind gust by tomorrow afternoon.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...SBH
LONG TERM...GEOGERIAN
AVIATION...DJ
Area Forecast Discussion
National Weather Service Marquette MI
746 PM EDT Mon Mar 26 2018
.SHORT TERM...(This evening through Tuesday)
Issued at 357 PM EDT MON MAR 26 2018
Challenging fcst shaping up for tonight with regard to ptypes. Water
vapor imagery and RAP analysis show a shortwave trof moving across
the northern Rockies toward the northern Plains while downstream mid-
level ridge is shifting toward the E Coast. The shortwave trof will
swing across the Upper Lakes on Tue. In the sw flow currently over
the central CONUS, pcpn has been lifting across MN today. Drier low-
level southeasterly flow across Upper MI has held this pcpn off to
the w so far this aftn.
As upstream shortwave trof approaches, a band of strong isentropic
ascent will shift across the area tonight. This isentropic ascent
will last roughly 6hrs at each location, so looking at a roughly 6hr
period of steadier pcpn. Main challenge is ptype as fcst soundings
show thermal profile around 0C thru a deep layer from the sfc to at
least 5kft. NAM has been on the colder side, suggesting more snow or
mix of snow/rain. Bulk of other guidance is supportive of more of a
rain scenario with some snow mixed in at times. In reality,
differences are quite minor now, but of course, these minor
differences have a big impact on ptype given the temp profile near
0C in the lower levels. It would appear the best potential of seeing
some snow will be across the w and n central during the earlier
stage of the pcpn period as evaporative cooling may be just enough
to send the temp profile mostly to or slightly blo 0C. The nw fcst
area has the best chc of pcpn remaining a snow to snow/rain mix. If
any locations remain mostly snow, could see a couple of inches of
sloppy/wet snow accumulation. As the isentropic ascent tails off
overnight/Tue morning, models are in very good agreement in showing
mid-level moisture departing, so a ptype change toward just -dz
seems like a good bet before pcpn ends. Finally, there is the
question of whether any of the rain/-dz may freeze on ground
surfaces as air temps fall to around 33F. MI DOT weather sensor
sites show sfc road temps rising way above freezing this aftn.
Hoewver, there is probably some potential for liquid to freeze on
some road surfaces later in the night as cold from farther blo aids
sfc cooling. Best potential will be on those sections of road that
are mostly shaded during the day. Of course, those lesser traveled
roads that still have ice/hard compacted snow cover will be
especially slippery with the addition of water. For now, will issue
an sps regarding the potential since the Tue morning commute will be
affected if roads do become slippery in spots.
On Tue, patchy -dz over the w half will become confined to the
higher terrain under upsloping wnw winds before ending by aftn. Over
the e, lingering -shra early will transition to some -dz before
ending mid aftn. Fairly aggressive drying should gradually clear out
lingering low clouds from nw to se during the aftn. Clouds will hang
on longest over the interior w high terrain and over e. CAA behind
the trof is weak, and combined with a warmer start to the day, temps
well away from Lake Superior will rise well into the 40s, and maybe
topping 50F s central. Temps will be no higher than the low/mid 30s
where w to wnw winds are onshore from Lake Superior.
.LONG TERM...(Tuesday night through Monday)
Issued at 326 PM EDT MON MAR 26 2018
Expect the weather through the middle/end of the work week to remain
active with multiple shortwaves embedded withing longwave troughing
moving across the region. We will get a taste of spring on
Wednesday, but with a cold front dropping southeast across Upper
Michigan Wednesday night, and then another one on Friday, expect a
cooling trend through the end of the work week. Should see
precipitation, mostly in the form of snow, develop as these cold
fronts push through the area mostly out west on Wednesday night, and
then across much of the area on Friday. Ahead of and behind these
cold fronts, expect breezy conditions to develop, especially on
Wednesday through Thursday morning.
The stronger surge of cold air advection will follow the second cold
front, and push temperatures down around freezing during the day and
teens to lower 20s during the overnight hours this weekend. This
colder air should be cold enough to foster lake effect snow near
Lake Superior over the weekend into early next week. Right now it
appears that areas across the northwest wind snow belts will have
the best chance at seeing this lake effect snow, but will need to
monitor how ice cover and 850mb flow evolves. The medium range
models continue to hint towards the potential of a system tracking
across the Great Lakes over the weekend. With the GFS being the
faster and further north with the deeper moisture compared to the
ECMWF and Canadian, confidence is not high in how things will unfold
Friday night through Saturday night. Based on the track of the
system in the GFS and forecast soundings showing deep lift through
the DGZ, the GFS would favor a system snow event across the area
Friday night into Saturday; whereas, the other extreme is the
Canadian, which is much further south with the deeper moisture and
would favor chances for impactful wintry precipitation well south of
Upper Michigan. Given the uncertainty, opted to not make any
adjustments to the blend through the weekend into early next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 745 PM EDT MON MAR 26 2018
VFR conditions will linger through much of this evening. However,
an approaching trough will spread pcpn across the area tonight
with cigs/vis deteriorating to IFR to LIFR. There is uncertainty
with the pcpn type due to temps in the lowest several thousand
feet being near freezing. KCMX has best chance of seeing more
snow than rain with KIWD/KSAW probably seeing more rain than snow.
In addition, as sfc temps fall to near freezing, there may be
some concerns with ice development on runways. The pcpn will
diminish overnight though some -dz/-fzdz may linger into the
morning at KIWD/KCMX due to upslope wnw winds following the trough
passage. Clouds will clear out with improvement to VFR from w to
e Tuesday aftn.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 357 PM EDT MON MAR 26 2018
Ahead of an approaching low pres trof, winds will mostly be
southeasterly at 20-30kt over the e half of Lake Superior thru early
Tue morning. Over western Lake Superior, e to ne winds will be
lighter. Passage of the trof late tonight thru mid aftn on Tue will
switch winds to a westerly direction at around 20kt thru Tue
evening. Winds will be mostly under 20kt on Wed, then passage of a
cold front Wed night will bring nw winds upwards of 20-30kt into Thu
morning, strongest over the e half of the lake. Winds will then
diminish. A trof will pass across the area Thu night/Fri morning,
but winds should remain mostly under 20kt for Fri and then on into
Sat.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...Ritzman
AVIATION...JLB
MARINE...Rolfson
Area Forecast Discussion
National Weather Service Charleston WV
1046 PM EDT Mon Mar 26 2018
.SYNOPSIS...
Warm front tonight into Tuesday. A front with waves of low
pressure meanders nearby Wednesday and Thursday, then finally pushing
through on Friday. Brief high pressure next weekend.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 1040 PM Monday...Refined the timing of PoP based on Radar
and HRRR trends. Very dry air still over the region with dew
points in the low 20s, so have decided to keep PoP below
categorical. Have contemplated putting out a winter weather
advisory for the Eastern Mountains for a brief period of
freezing rain, but still some uncertainty when precipitation
will arrive. If precip arrives before sunrise, there may be some
slick spots on untreated roads and overpasses/bridges. Will
continue to highlight in HWO for now and midshift will monitor
to see if precipitation will make into the area before
temperatures start to climb tomorrow morning.
As of 740 PM Monday...
Slowed down the arrival of rainfall a bit, but have also
increased PoP for when the rain eventually makes it here. Based
on current Radar and Meso Model Trends, it looks like rain will
enter Western CWA between 03Z to 04Z.
As of 155 PM Monday...
A warm front, extending from low pressure over the upper
Mississippi Valley, will move across the region tonight. This
will generate some light rain showers over eastern Ohio and
northern West Virginia. The pressure gradient, between the
front and high pressure exiting off to the east, will keep winds
up tonight, this will keep temperatures on the warm side,
especially south and west. Temperatures in the protected
Northern Mountain valleys will be cold enough for any light rain
to start out as freezing rain early tomorrow morning. This
freezing rain will be short lived as temperatures will quickly
rise above freezing shortly after daybreak. Generally went with
a blend of guidance throughout.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 330 PM Monday...
The area is solidly in the warm sector to start the period
Tuesday night with a warm front North of the area. The frontal
zone extends down the western Middle-Ohio Valley and into KY
with rain showers possible everywhere along it. A decaying wave
moving along the boundary will bring showers across the area for
Wednesday. In spite of weakening forcing, 1.3" PWAT indicates a
very moist atmosphere - so, any showers that do form have the
potential to contain moderate rainfall rates. Heavy showers are
possible if forcing is better realized. For now, have up to
.75" rainfall possible during the day Wednesday although locally
higher amounts are likely with training.
Anomalously high PWAT continues through the duration of this
system. The wave that ultimately kicks this system out toward
the East spurs cyclogenesis out of the Ark-La-Tex region with a
matured surface low moving up the Tennessee and Ohio River
Valleys Wednesday through Thursday. Long range models have
(finally) come into better agreement with this low tracking up
the Ohio River in our area during the day Thursday. With it,
heavy rain is possible - another thing to keep an eye out for is
severe weather. Particularly, low-level wind shifts near the
low and bulk shear around 60 kts with a strong jet aloft
certainly suggests ample dynamics - however instability will be
limited with warm air through the column.
By the time the boundary moves on toward the East, up to 2" of
rainfall are possible in isolated areas. In general, highest
amounts will be toward the West and South - however wave
placement along this boundary will ultimately dictate the
corridors of heaviest rainfall.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 355 PM Monday...
Due to divergent model guidance during the long term,
particularly for Saturday onward, have opted to stick with a
general blend of long-range models for precipitation and
temperatures. Northwest flow generally cools the region down
after the passage of the aforementioned front in the short-term.
Long- range models indicate varying vort and jet maxima
bringing brief periods of rain showers in otherwise weak high
pressure through the weekend but at differing times and as a
result of features that are present in some models but not
others. Flow aloft shifts zonal and eventually southwesterly to
start the work week implying a warming trend - but again, major
long- range models differ on the timing with this.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
As of 735 PM Monday...
A warm front will move across the region tonight. Clouds will be
on the increase as well as some rainfall across the region.
At this time, not expecting IFR conditions with this feature,
but MVFR conditions will be possible, especially in rainshowers.
Across the mountains there is a chance for some icing early
tomorrow morning, although confidence is low whether or not any
freezing rain will occur at EKN. If it does occur, it will
likely only be for a brief period during the morning hours.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z WEDNESDAY...
FORECAST CONFIDENCE: medium to High.
ALTERNATE SCENARIOS: Timing of MVFR conditions with precipitation
may vary late tonight and through the day on Tuesday.
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 03/27/18
UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
EDT 1HRLY 23 00 01 02 03 04 05 06 07 08 09 10
CRW CONSISTENCY H H H H H H H H H H H M
HTS CONSISTENCY H H H H H H H H H H H M
BKW CONSISTENCY H H H H H H H H H M M L
EKN CONSISTENCY H H H H H H H H H H H L
PKB CONSISTENCY H H H H H H H H H M M L
CKB CONSISTENCY H H H H H H H H H L M M
AFTER 00Z WEDNESDAY...
No widespread IFR conditions foreseen.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.
&&
$$
SYNOPSIS...JS/26/MC
NEAR TERM...JS/MPK
SHORT TERM...MC
LONG TERM...MC
AVIATION...MPK