Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/07/18
Area Forecast Discussion
National Weather Service Wakefield VA
956 PM EDT Fri Apr 6 2018
.SYNOPSIS...
A strong cold front crosses the region Saturday morning with low
pressure tracking along the boundary Saturday afternoon and evening.
Canadian high pressure builds into the area Sunday. Another frontal
system moves across the region Monday and Monday night.
&&
.NEAR TERM /THROUGH EARLY SATURDAY MORNING/...
Update...
Very dry low levels keeping any rain from really entering the
forecast area. However, expect rain to enter the western
forecast area in the next few hours and rapidly expand eastward
overnight as the cold front approaches from the north and
moisture stream northeast. As such, will maintain the
categorical pops overnight across much of the area.
The cold front will enter the far northern part of the forecast
area around 08z the continue to move southward tonight into
Saturday morning. It will stay mild ahead of the front with
temperatures in the mid-upper 50s. Temps will drop sharply
behind the front, with areas north of the front dropping into
the low-mid 40s in an hour or two.
Main change in this update is to introduce thunder across the
far south late tonight into Saturday morning. Latest CAMS
guidance suggests an area of convection developing ahead of the
front over southside VA and NE NC after 09z. In fact, the 23z HRRR
and the 18z NAMNest suggest that the convection may gain some
organization as it moves through. This is likely due this area
being at the nose of a 40-50kt 850mb jet late tonight. This area
is in a marginal risk for severe weather from SPC for day 2.
Although instability is very marginal, the 0-3km bulk shear
will be quite strong (around 60kt) with the SHERB parameter
approaching 1 owing to the strong shear and lapse rates near
moist adiabatic. As such, one cannot complete rule out severe
storms late tonight across the far south. However, as with many
of these high shear/low CAPE events, thunderstorm development
and subsequent severity is very challenging to forecast.
As for the winter weather potental tomorrow into tomorrow
night, no major changes to the current forecast. Still looks
like there will be some type of lull in pcpn late tomorrow
morning into the afternoon post fropa, but pcpn will move back
into the area later Saturday afternoon into Saturday night as
low pressure develops along the front and intensifies just
offshore. Still looks like enough cold air will be in place for
a mixture of rain/sleet/snow across the northwest 1/3 of the
local area during the day on Saturday gradually changing to all
frozen precipitation later Saturday into Saturday evening as
more cold air filters in behind the low. In fact, the forecast
has some type of frozen pcpn possible all the way to the beaches
Saturday night. Still think there will be a band of 1-2 inches
of snow somewhere across central VA into the lower MD eastern
shore. Current thinking is that this will set up from south of
PTB N-NE through Tappahannock and into the MD eastern shore.
However, given the complexity of the forecast this is still
subject to change and most likely will. Since it will be falling
at night, there is a potental at least for some slushy
accumulations on roadways where the heaviest rates occur. If the
trends continue, a winter weather advisory may be needed for a
portion of central VA and MD eastern shore for late Sat/Sat
Evening, but will let the overnight shift look at the latest
data to make that decision.
Previous discussion below...
Latest MSAS has low pressure over the Great Lakes region with
the warm front extending ese across Pa and the trailing cold
front extending sw through the OH/KY valley.
Latest data has the cold front moving se across the region after
midnight, reaching near the VA-NC line by 12Z. Thus, mild temps
expected through the evening hours. Moisture from the leading srn
stream s/w overspreads the local area late this evening and through
the overnight hrs. Despite temps falling behind the fropa, thicknesses
support liquid through 12Z Sat with likely to categorical pops after
06Z. Some mdt rainfall psbl late. Lows upr 30s north to lwr 50s south.
&&
.SHORT TERM /SATURDAY MORNING THROUGH MONDAY/...
Winter not wanting to leave in any hurry which is leading to a
very challenging weekend forecast given it is the first week in
April. Models now showing the moisture with the first s/w moving
south into NC by the afternoon with a "lull" in the steadiest
pcpn over VA/MD thru about 21Z. Thermal profiles along with sfc
temps and pcpn intensity will be the determining factors in
Saturdays p-type. A warm nose at H85 and marginal sfc temps will
likely result in rain across NC and southside VA, a rain/sleet
mix across VA/MD. Some wet snowflakes across nrn most zones
late. Highs tomorrow will likely be at 12Z with readings falling
into the mid 30s north to lwr 40s south by 21Z.
Second and most important piece of energy progged across the ern
half of the local area btwn 22Z Sat-08Z Sun as the low deepens off
the coast allowing for a second round of widespread pcpn to
overspread the area. This pulls in colder air after dark allowing
for a changeover to snow inland and a mix p-type along the coast.
Key to this pcpn will be where any frontogenetic bands form allowing
for what might be a several hour period of mdt pcpn. This is where
most if any accumulating snows would occur given marginal sfc temps
hovering in the low to mid 30s. For now, will go with a 1-2 inch
swath from the RIC/PTB metro areas on ne to the nrn neck and lwr MD
ern shore. Still looks like an advsry event at this point so no
headlines with this forecast package. Sern sections will see rain
then a mix before ending late. Decreasing clouds west-east late
as the low pulls farther away from the area and high pressure builds
in from the west. Lows upr 20s nw to mid 30s sern coastal areas.
Mostly sunny and chilly Sunday as high pressure moves over the region.
Highs upr 40s to lwr 50s.
Next system approaches from the west Sunday night, but the latest
models keep any pcpn west of the fa thru 12Z. Still can`t rule out a
light mix across nwrn zones arnd daybreak Mon. Lows lwr 30s nw
to upr 30s se. Another cold and wet day Monday with chc to likely
pops. Highs mid 40s to mid 50s.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A weak area of low pressure passes well north of the region during
the day on Tuesday. The associated cold front passes through the
region Tuesday bringing the chance for rain showers, mainly across
northern portions of the area. Models also indicate a southern
stream low pressure area developing off the southeast coast, but
there still remains uncertainty on how strong and near the coast
this feature will be. Brought in higher PoPs across the far
southeast Tuesday to account for this uncertainty. High pressure
builds south of the region Wednesday allowing for dry conditions and
a warming trend for Wednesday and Thursday. A weak cold front may
impact the region later Thursday into Friday, but moisture appears
limited with this system at this time. High pressure returns Friday
allowing for the potential for even warmer temperatures.
Temperatures begin warmer on Tuesday, but still below average, with
highs ranging from the upper 50s to low 60s. Clearing skies will
allow for temperatures to dip into the mid 30s across the west
Tuesday night, temperatures drop into the low to mid 40s near the
coast. A warming trend is anticipated for the second half of the
work-week withs highs near 60 on Wednesday and climbing up into the
mid to upper 60s on Thursday. Lows remain below average Wednesday
night, upper 30s to low/mid 40s, but warm Thursday night to near 50
degrees. Mild conditions expected for next Friday with highs topping
out in the upper 60s NE to mid/upper 70s SW.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions will start out the forecast period this evening.
However, as a cold front approaches from the northwest, an area
of rain will quickly spread from SW to NE across the forecast
area tonight. With the dry low levels, expect VFR conditions to
continue even at the onset of rain. However, expect all sites to
become MVFR by morning as the cold front moves through the area.
Expect the cold front to pass through the area later tonight
into early Sat morning quickly causing winds to shift to the N.
The rain may end for a period of time Saturday morning into
Saturday afternoon at SBY and RIC, which may allow CIGS to rise
to VFR. However, at PHF/ORF/ECG expect CIGS to remain MVFR or
even lower to IFR this area will stay in the rain for much of
the day. Low pressure develops along the front over NC Sat aftn
causing additional precipitation to spread northward. However,
it will likely be cold enough for a snow/ice pellet mix at RIC
by late Saturday afternoon.
OUTLOOK...
Another low pressure system potentially impacts the area Monday
bringing another round of MVFR conditions or lower along with a
chc of showers. Weak high pressure returns Tuesday.
&&
.MARINE...
A new SCA has been issued for the rivers and is in effect
Saturday morning through Sunday morning. Winds may gust as high
as 30 to 35 knots Saturday evening and overnight, especially at
the mouth of the James River. Otherwise, minimal changes to the
marine forecast on the evening update.
Previous Discussion: SCAs for the entire marine area (except
ANZ658) continue through 8pm for SW winds 15-25kt w/ gust to
30kt. This is being caused by a decent pressure gradient between
offshore high pressure and a cold front slowly approaching from
the west. By the time sunset arrives, expect the winds to begin
to relax as mixing wanes with SW winds 10- 15 kt by midnight.
Attention then turns to the approaching cold front which is
expected to push across the marine area by daybreak Saturday. A
strong northerly push of cold air behind the front will cause
SCA conditions to re-develop for much of the marine area during
Saturday for NNE winds of 15-25 kt with gusts up to 30 kt. Low
pressure riding NE along the cold front will deepen as it
emerges off the OBX Sat evening allowing solid SCA conditions to
continue for much of the marine area Saturday night. As the low
pushes farther offshore on Sunday, conditions will slowly
improve through the day. Depending on how rapidly and intensely
the sfc low deepens off the OBX Sat evening, there is the
potential for a period of gale conditions (gusts 35-40kt) south
of Cape Charles and possibly into the lower Bay. After
coordination with MHX, plan to hoist a Gale Watch to cover this
potential. Waves build to 3-5 ft on the Ches Bay by late Sat
with seas building to 5-8 ft on the coastal waters (highest
south). As far as SCA headlines, have extended SCAs for the Ches
Bay and coastal waters from now thru late Sat when Gale Watch
replaces them. SCA for ANZ658 and also and additional SCA for
the Sound go into effect 10am Sat thru 7pm Sat when Gale Watch
also replaces it. SCA for the Rivers come down at 8 pm this
evening, but a new SCA will likely need to be issued at that
time to cover the next event on Saturday. A period of benign
boating conditions is expected early next week.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory from 7 AM Saturday to 10 AM EDT Sunday
for ANZ635>638.
Gale Watch from Saturday evening through Sunday morning for
ANZ632>634-654-656-658.
Small Craft Advisory until 7 PM EDT Saturday for ANZ632-634-
654-656.
Small Craft Advisory from 10 AM to 7 PM EDT Saturday for
ANZ633-658.
Small Craft Advisory until 10 AM EDT Sunday for ANZ630-631.
Small Craft Advisory until 6 PM EDT Sunday for ANZ650-652.
&&
$$
SYNOPSIS...MPR/WRS
NEAR TERM...MRD/MPR
SHORT TERM...MPR/WRS
LONG TERM...AJB
AVIATION...MRD
MARINE...AJB/JDM
Area Forecast Discussion
National Weather Service Boston/Norton MA
1008 PM EDT Fri Apr 6 2018
.SYNOPSIS...
A cold front will cross southern New England late tonight. This
will be followed by a mainly dry and chilly weekend, although
some snow is possible for the Cape and Islands Saturday night
into Sunday morning. High pressure brings dry and chilly weather
Monday. Still watching a potential coastal storm Tue. Milder
temperatures return Thursday and may be accompanied by some
showers as a cold front approaches.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
10 PM Update...
Not much change to previous forecast. Warm sector continues to
overspread the coastal plain including much of RI and southeast
MA with temps and dew pts in the 40s. This is resulting in some
patchy fog especially where lingering patchy snow cover remains.
Scattered showers will persist overnight with a trend for these
rain showers to change to snow showers late especially across
northern MA. Previous forecast verifying nicely and captures the
details mentioned above, so no major changes with this update.
Earlier discussion below.
=================================================================
Warm front is slowly lifting north across southern CT, RI, and
SE MA where temperatures have risen into 40s this evening. Warm
sector should make it a little farther NE but many areas along
and north of Mass Pike will remain in cool sector, before cold
front crosses SNE later tonight.
Strongest wind gusts, on order of 30-40 mph, expected on Cape
Cod and Islands through this evening.
Band of showers along front in Berkshires will slowly make its
way eastward tonight, and timing from HRRR seems reasonable.
Overall, forecast is in good shape and only minor adjustments
made.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Any leftover snow/rain showers along the south coast at daybreak
Saturday, quickly moves offshore as a cold front moves farther
offshore. Below normal temperatures continue, with not a lot of
sunshine expected near the coast. The greatest chance for more
sunshine will be across the interior.
Another low pressure should track well S and SE of the 40N/70W
benchmark late Saturday night. At this moment, thinking minimal
impact for the Cape and islands. There will be gusty NE winds,
as well as a risk for some light snow and/or rain. That said, it
would not take much of a NW jog to the track, only about 40-50
miles, to produce a more significant impact. That is well
within typical model error for a 24-36 hour forecast. So cannot
completely dismiss this storm at this time. Below normal
temperatures continue, but not by as much as during the day
Saturday.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Highlights...
* Lingering snow Cape/Islands ending Sun morning
* Chance of rain Tue/Tue night
* Milder temps Thu/Fri
Sunday...
Coastal storm tracks well south and east of the benchmark Sun
morning. Snow is expected to linger into Sun morning over
Cape/Islands and possibly into SE coastal MA before moving offshore.
Some minor additional accum possible Sun morning on non paved
surfaces as temps will be a bit above freezing. However, there are
still a few ensemble members that have a more significant impact for
SE New Eng so still have to watch for a possible westward shift in
the guidance. Otherwise, developing sunshine will give way to more
clouds mid to late afternoon low to mid level moisture increases
ahead of approaching mid level trough. Temps mostly in the 40s, well
below normal, and gusty N/NE winds over Cape/Islands will diminish
during the day.
Monday...
High pres in control will bring sunshine and diminishing winds but
temps remaining well below normal.
Tuesday into Wednesday...
Consensus of the deterministic and ensemble guidance has trended
much further offshore with potential coastal storm. It is still
possible that guidance brings this storm back but probability is low
at this time. Approaching mid level trough with sfc reflection in
the form of an inverted trough may lead to some rain/snow showers
late Tue/Tue night, otherwise improving conditions Wednesday. Temps
below normal.
Thursday and Friday...
Another shortwave passage will bring another round of showers
sometime Thu or Thu night, but timing is uncertain. Significant
differences between GFS and ECMWF with respect to northern stream
trough passage which impacts Fri temps. ECMWF much further south
with eastern Canada vortex and results in a strong fropa and much
cooler airmass than GFS for Fri...40s vs 60s. Very low confidence
temp forecast for next Fri.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Saturday Night/...
Tonight...High confidence.
VFR ceilings expected tonight, although they should lower to
MVFR near Cape Cod and Islands and perhaps across higher
elevations tonight. Showers moving through later tonight,
roughly 02z-09z, may bring MVFR visibilities for a few hours.
S/SW winds tonight, gusting to 30kt near Cape Cod and Islands,
shift to W/NW overnight.
Saturday...High confidence.
MVFR along south coast in scattered rain/snow showers early, but
trending dry in the afternoon along with conditions lifting to
VFR. Elsewhere, VFR and dry weather. Gusty WNW winds up to 25 kt
early diminish during the day.
Saturday Night...High confidence.
VFR. Low risk for MVFR in scattered SHRASN across the Cape and
islands late. Gusty NE winds up to 25 kt across SE MA and
coastal RI.
KBOS Terminal...High confidence in TAF.
KBDL Terminal...High confidence in TAF.
Outlook /Sunday through Wednesday/...Moderate confidence.
Sunday through Monday: VFR. Breezy.
Monday Night: VFR.
Tuesday: Mainly MVFR, with areas VFR possible. Breezy. Chance
RA.
Tuesday Night: Mainly VFR, with areas MVFR possible. Chance RA.
Wednesday: VFR.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Saturday Night/...
10 PM update...
Mainly a mix of VFR and MVFR across the region along with
scattered rain showers. As cold front slips south and cold air
bleeds into the region expected rain showers to change to snow
showers toward morning from north to south. Runways will remain
warm enough to stay wet with any minor slush accumulation
confined to non paved surfaces. Previous TAFs capture these
details so no major changes expected. Earlier discussion below.
=================================================================
Tonight...High confidence.
S/SW winds have been gusting near Gale force on south coastal
waters due to strong winds aloft, but gusts should remain
between 25 and 30kt for most part this evening. Cold front
crosses waters overnight with wind shift to W/NW and gusts
increasing back to 25kt toward daybreak.
Saturday...High confidence.
Cold front along the south coast drives offshore during the
afternoon. WNW winds up to 25 kt in the morning, then
slackening somewhat in the afternoon. Any lingering scattered
rain/snow showers early move offshore with dry conditions and
improving visibility. Rough seas slowly subside across the
outer coastal waters.
Saturday Night...Moderate confidence.
Seas continue to slowly diminish across most waters. Gusty NE
winds should develop after midnight. Areas of seas approaching 5
ft. Chance of snow and rain with local visibility 1 to 3 nm on
the waters around the Cape and islands.
Outlook /Sunday through Wednesday/...Moderate Confidence.
Sunday: Low risk for Small Craft Advisory winds with gusts up
to 30 kt. Areas of rough seas. Chance of snow.
Sunday Night through Monday: Winds less than 25 kt. Local rough
seas.
Monday Night: Winds less than 25 kt. Areas of seas approaching
5 ft.
Tuesday: Winds less than 25 kt. Chance of rain.
Tuesday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. Chance of rain.
Wednesday: Winds less than 25 kt. Seas locally approaching
5 ft.
&&
.EQUIPMENT...
Due to our move to the new forecast office in Norton, MA, one
NOAA Weather Radio transmitter is not yet on the air:
Hyannis, MA transmitter.......KEC73.....162.550 MHz
It appears that the issue may be resolved by early next week.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...Small Craft Advisory from 6 AM to 8 PM EDT Saturday for RIZ008.
MARINE...Small Craft Advisory until 6 AM EDT Saturday for ANZ232-234.
Small Craft Advisory until 8 PM EDT Saturday for ANZ233-235-
237.
Small Craft Advisory until 10 AM EDT Saturday for ANZ231-251.
Small Craft Advisory until 4 PM EDT Saturday for ANZ250.
Small Craft Advisory until midnight EDT Saturday night for
ANZ254.
Small Craft Advisory until 6 AM EDT Sunday for ANZ255-256.
&&
$$
SYNOPSIS...Belk/KJC
NEAR TERM...Nocera/JWD
SHORT TERM...Belk
LONG TERM...KJC
AVIATION...Belk/KJC/Nocera/JWD
MARINE...Belk/KJC
EQUIPMENT...Staff
Area Forecast Discussion
National Weather Service Dodge City KS
956 PM CDT Fri Apr 6 2018
...Updated to expand Winter Weather Advisory east on tier of
counties...
.UPDATE...
Issued at 945 PM CDT Fri Apr 6 2018
Radar trends supporting the latest RAP in focusing a band of
steadier and heavier snowfall moving from Scott county towards
Stafford and Pratt counties early tonight. Phone calls made to
these counties as of 02z suggests the snow amounts from the RAP may
be over done but have been receiving reports of slick roads
developing. Given that more snow is expected in the Stafford and
Pratt county areas over the next several hours will be expanding
the winter weather advisory to these counties overnight. Did not
include Barber county because of lower snow accumulations expected
in this county and the report of dry roads at this time with no
snow/trace on the ground as of 02z.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 1228 PM CDT Fri Apr 6 2018
Overcast skies and cooling temperatures will continue through this
afternoon and evening hours as arctic air continue to pump in from
the north behind a cold front that pushed through the entire area
earlier this morning. High temperatures for today were met this
morning and have been slowly decreasing since expecting to do so
continually over night and into Saturday morning. This cold air
mass will be reinforced later this evening as post frontal
troughing will act as a mechanism to lift a light snow potential
for most of the CWA between 6PM and 3AM currently with a winter
weather advisory out for accumulations up to 2 inches. All models
are agreeing for the amount of 1-2 inches as well as timing
expanding its coverage every model run since yesterday. PoPs
have increased up to the 80 range for some areas since a light
snow accumulation of some sort is expected for most if not all of
the area. No ice is expected as soundings show a cold, moist layer
saturated all the way from the upper levels to the surface below
the freezing point for this time period. The surface will drop
below the freezing mark later this afternoon before the
aforementioned frozen precipitation is expected to start this
evening.
Saturday morning will see some record low temperatures for much of
the area with temperatures in the teens for most spots. Models
are showing slightly colder temperatures, but the clouds don`t
look to push out until early in the morning not allowing the
temperatures to go as low as the some models like the RAP and EC
are indicating. The snow cover that accumulates will help keep
these temperatures down as well allowing for records to be met in
the morning. Arctic high pressure will continue to pump into the
area from the north clearing skies completely by mid morning
allowing temperatures to surge into the 40s for the entire CWA and
close to 50 for the southwestern counties to include Elkhart.
Once tonight`s weather comes to a close, no other significant
weather impacts are expected in the near term with a warming trend
expected in the long term outlook.
.LONG TERM...(Saturday night through Friday)
Issued at 148 PM CDT Fri Apr 6 2018
Sunday morning will start on a more mild note as compared to
Saturday morning with lows in the upper 20s to lower 30s. A minor
short wave trough will propagate along the northern periphery of
the CWA increasing PoPs up to the 30-40% range in the I-70
corridor with a good uplift and ample low level moisture from the
previous days precipitation that fell. Low level upslope flow will
help aide in this factor with easterly winds allowing snow to
lightly fall across the northern counties. Very minor
accumulations are expected if at all less than a quarter inch as
depicted by most of the models. Soundings show moist and cold low
levels below freezing, and no ice accumulations are expected at
this time as well. Other areas might see some restrictions in
visibility due to mist and fog that may develop in isolated areas
where precipitation fell the most over the previous day. Coupled
with the moist upslope flow, this could be a more widespread event
in some of the southern counties. By mid morning, diurnal heating
will burn off any fog that may develop in these areas as winds mix
down through the boundary layer eroding the temperature inversion
that set up over night. Temperatures will rise well into the 50s
and even 60s in the western counties, melting away any snow that
may fall in the northern sections of the CWA. Sunday night low
temperatures will stay above freezing in the areas of melted snow,
so no refreezing is expected with mid 30s expected.
The beginning of the work week starting Monday will see a warming
trend as upper level ridging pushes across the Rocky Mountain West
and High Plains region with high pressure stacked down to the
surface extending across western Kansas. Lee side troughing will
develop Monday and extend through the remainder of the week
bringing in a stronger and warmer downsloping wind from the
southwest. With this, relative humidity values will drop into the
teens and 20s percent for most of the CWA, and thus increasing the
fire danger risk all week with Red Flag Warning criteria coming
into play by middle of the week on Wednesday and Thursday. Long
term models have pulled back on any significant weather events for
the end of the week into Friday, but something to keep an eye on
as we push into next week. Aside from the fire danger and
increasing winds, no other significant weather events are
forecasted with highs pushing into the 80s by Wednesday and lows
only in the 40s to maybe show that Spring has finally come to stay
this time around.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 621 PM CDT Fri Apr 6 2018
Mid level forcing ahead ahead of an upper level wave as it
crosses western Kansas overnight which will result in a period
(3-6hrs) of light to moderate snow for western Kansas. During this
time frame 1 to 2 inches will be possible. In addition to the
snow, the ceilings will be lowered into the IFR or even a brief
period of LIFR category. A period of low visibilities are also
possible in the steadier and heavier snowfall. Latest models
indicate the time frame for the most inclement conditions will be
from 00z to 03z Saturday at Hays, and 02Z to 06z Saturday at
Garden City. Lower visibilities and ceiling are then expected
from 03z to 07z at Dodge City and possibly even Liberal. Once this
system passes the ceilings will improve as the snow tapers off to
flurries before ending. Northeast winds at around 20 knots early
tonight will begin to decrease to around 15 knots between 06z and
09z Saturday. By 12z Saturday northeast winds are expected to be
10 knots or less.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 14 40 28 58 / 80 0 40 10
GCK 14 42 29 59 / 80 10 30 10
EHA 18 50 35 63 / 60 10 10 10
LBL 16 44 30 63 / 70 10 20 10
HYS 11 42 27 53 / 80 0 40 10
P28 16 43 28 57 / 70 0 30 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 3 AM CDT /2 AM MDT/ Saturday for
KSZ030-031-043>046-061>066-074>081-084>089.
&&
$$
UPDATE...Burgert
SHORT TERM...Lowe
LONG TERM...Lowe
AVIATION...Burgert
Please see the 00Z aviation forecast discussion below.
AVIATION...
The main concern in the short term will be the chance for showers and
thunderstorms for roughly the first six hours of the forecast period.
Ongoing radar trends and hi-res model data suggest scattered
thunderstorms will be possible at AUS between 04-05Z and we have
added a TEMPO group for a -TSRA and variable winds. Farther south at
SAT and SSF, we expect a decreasing chance for convection and will
only mention VCSH at this time. No precipitation is expected out west
at DRT during the forecast period. Otherwise, the focus will turn to
a strong cold front set to move in during the late evening and early
morning hours. Some minor adjustments have been made to the timing of
the front with a slightly earlier arrival now expected. Gusty north
winds, especially along the I-35 corridor, will continue through
tomorrow afternoon. We also expect upper end IFR cigs around the time
of the frontal passage, with cigs increasing to MVFR during the
morning hours.
PREV DISCUSSION... /ISSUED 348 PM CDT Fri Apr 6 2018/
SHORT TERM (Tonight through Saturday)...
Main weather headlines remain centered on two hazard types for this
afternoon and into Saturday afternoon:
1) Conditional isolated strong to severe thunderstorms capable of
large hail, 40-60 mph winds, and frequent lightning across far
northeast Hill Country into the northern I-35 corridor and southeast
towards College Station.
- Timing: Early evening to 1-2am
- Confidence is low to medium on occurrence.
2) Strong north winds of 20-25 mph sustained with gusts to 35-40 mph
are expected behind a cold front. A wind advisory may be needed.
- Timing: Early Saturday morning through Saturday afternoon
- Confidence is high on occurrence.
Surface analysis depicts a strong cold front just north of the Red
River and a propagating dryline across north-central Texas shifting
west to east. A warm-moist sector exists south of I-20 and east of
I-35 characterized by ample instability of 2500-3000 J/kg, deep layer
shear of 45-55kt with hindering -25 to -75 J/kg of CIN keeping a
capping inversion in place. Aircraft soundings out of Austin over the
past several hours also indicate a strong cap remains in place.
Additionally, limited low-level convergence is ongoing with laminar
surface wind fields across the Hill Country northward to Dallas
Metroplex. The capping inversion is weaker farther north and
convective evolution could allow for isolated to scattered storms to
develop across central Texas to north-central Texas ahead of the
front this afternoon. Lapse rates are very steep and thus large hail
will be the primary hazard with these storms. Given the stronger cap
and lack of medium to strong forcing aloft with limited evidence of a
shortwave impulse, much of the region should remain storm free
through 6-7pm. The one caveat is if the cap weakens more then
expected an isolated supercell could develop in the far northeast
Hill Country to northern I-35 corridor north of Austin towards Waco.
If this does not happen, then storms are expected to develop north of
the region along the front and shift south. Again, with lack of
strong forcing aloft and the stronger cap in place, the strong to
possibility severe storms north of the area could reach into the far
northeast Hill Country of Burnet and the the I-35 corridor of
Williamson to Lee. Farther south, the cap appears too strong and
storms should weaken as the front moves south late tonight.
The surface pressure gradient will tighten overnight and through the
day Saturday behind the front as a strong high pressure system moves
into the southern Plains. Wind gusts to 35-40 mph with sustained
winds of 15-25 mph will be probable Saturday morning through the
afternoon. A wind advisory may be needed for this time period.
Much cooler temperatures are expected Saturday with highs only
reaching into the 50s and remaining well below normal. Clouds and
strong north winds will certainly hinder warming. Have dropped highs
below guidance values.
LONG TERM (Sunday through Friday)...
Near-normal temperatures return by Sunday into early next week and
slightly-above normal through the rest of week. A slight chance of
rain will be possible early Tuesday with a reinforcing cool front
and system aloft moving over the area. An active period of unsettled
weather could occur late in the week as moisture and southwest flow
are re-established.
It will be much warmer Sunday then Saturday with south winds
throttling up as a strong low pressure system develops across the
southern Plains. Too little moisture/PWATs will exist for showers to
be possible Sunday. An amplified shortwave trough axis will shift
east across the southern plains late Saturday into Sunday. The
elevated H5 NW flow and attendant cool front will shift through
northern areas by Monday night and the rest of area Tuesday. Due to
greater lift aloft, some light showers could form as instability
remains low. Mid-week will be dry and warm despite the boundary
exiting south of the area with the strong April sun. Southwest flow
appears to be re-established over south-central Texas by late
Thursday into Friday as a vigorous shortwave trough develops over the
eastern Front Range. Confidence is low on exact timing and placement
with model differences. PWATs increase as atmosphere will not be
xeric in response to southerly wind fetch. Stay tuned for details.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 47 56 43 73 59 / 40 10 0 0 10
Austin Bergstrom Intl Airport 48 56 41 74 58 / 40 10 0 0 10
New Braunfels Muni Airport 52 60 43 75 59 / 30 10 0 0 -
Burnet Muni Airport 43 52 40 74 57 / 40 10 0 0 10
Del Rio Intl Airport 55 71 48 82 61 / - - 0 0 0
Georgetown Muni Airport 45 51 41 73 57 / 40 10 0 0 10
Hondo Muni Airport 55 67 44 79 60 / 20 10 0 0 0
San Marcos Muni Airport 50 59 42 75 58 / 40 10 0 0 -
La Grange - Fayette Regional 52 56 44 73 60 / 50 10 0 0 10
San Antonio Intl Airport 54 61 44 76 61 / 30 10 0 0 -
Stinson Muni Airport 56 62 47 78 61 / 30 10 0 0 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Mesoscale/Aviation...24
Synoptic/Grids...17
Public Service/Data Collection...Williams
Area Forecast Discussion
National Weather Service Wilmington NC
949 PM EDT Fri Apr 6 2018
.SYNOPSIS...
High pressure will continue to drift farther off shore as a low
pressure system approaches through tonight. The next cold front
will move across the eastern Carolinas Saturday evening,
bringing showers and thunderstorms. Some thunderstorms may be
severe. Weak high pressure and chilly weather will prevail on
Sunday. Low pressure may bring unsettled weather Monday and
cooler temperatures on Tuesday. High pressure and below normal
temperatures are expected for much of next week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 900 PM Friday...Some tweaking applied based on current obs
and latest trends and meshing it with the 18Z model consensus.
Latest sat imagery also massaged to the 18Z model runs. Overall,
no categorical changes to the various sfc parameters along with
sky and pops. Some changes may be needed for POPs and sky
conditions if the latest HRRR model runs continues to delay the
onslaught of pcpn.
Previous.................................................
As of 300 PM Friday...Issued a Fire Danger Statement for
increased fire danger due to combo of low RH and gusty southerly
winds. These gusty southerly winds will continue through much
of the night into early Saturday as high pressure shifts farther
off shore and gradient tightens with approach of next system. Lack
of forcing and presence of mid-level dry air will likely keep
the region dry through tonight. Precipitable water values
increase from half an inch this afternoon to just over an inch
late tonight as moisture increases through the column, but
mainly in the way of thickening higher clouds. Temperatures
should drop initially after sunset this evening with clear
skies, but increasing low level moisture, clouds and elevated
winds overnight should produce low temps in low to mid 60s.
Mid to upper trough over the northern plains will amplify as it
moves east, pushing a cold front south. Low pressure will
develop and move along this front toward the Carolinas on
Saturday. The cold front will push south into NC Sat aftn as
this area of low pressure deepens and pushes east through Sat
afternoon. Shallow cool air will push south behind the front
producing increased lift and potential for enhanced pcp behind
the front north and west of our area early Saturday. As low
pressure deepens and tracks along the front, winds will increase
through the low levels maintaining a strong southerly push of
warm and moist air. It looks like our local area should remain
in the warm sector through early afternoon and may even have
thinner cloud cover contributing to some surface heating and
destabilization of the air mass. Not feeling too confident of
the exact location of low pressure but it looks like the center
should approach GA/SC toward the end of the near term period.
Overall, as the low deepens and moves through SC, instability
and lift will increase with greatest potential for strong to
possibly severe storms increasing during max daytime heating
with best forcing along and ahead of the cold front as low
tracks E-NE along it. Temps will reach up into the 70s and
dewpoint temps will be up in the 60s south of the front. Winds
increase up to 45 to 50 kts above the sfc with good directional
shear associated with boundary. Pcp water values reach up near
1.6 inches along and south of low and frontal boundary in deep
moisture. Bulk Shear values will be up to 50 to 70 kts. SPC has
included much of our local forecast area in a slight risk of
severe storms with primary threat of damaging wind and an
isolated tornado possible. 0-6 km as mixed layer CAPE values S
and E of the low track reach up around 1000 J/kg.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 300 PM Friday...Cold front and flat wave of low pressure
to be traversing the area at the start of the period. The
immediate coastal counties will still be in the warm sector for
about the first three hours (00-03Z) and thus possibly under
severe weather threat, though this will be modulated by the
small remaining timing differences between models. Despite the
timing differences there is good agreement between GFS and WRF
in an impressive 60kt 925mb jet developing over the ocean as
well as half of Brunswick and New Hanover Counties. For the
remainder of the overnight expecting appreciable QPF as elevated
convection continues in strengthening cold advection regime
while a few upper impulses move overhead. Rapid dry advection
then gets underway at around 09Z and rain will end from west to
east.
Sunday will feel much more like February than April with a blustery
northerly breeze and highs that fail to hit 60. Thermal advection
reverts back to warm Sunday night atop the boundary layer leading to
increasing clouds. Carrying 20 POPs inherited but suspect they will
be dropped in future forecast. Saving grace of the cloud cover is
that they should minimize frost/freeze potential.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 300 PM Friday...A series of shortwaves will move across the
Carolinas Monday through Wednesday, digging yet another cold upper
trough. Following in the footsteps of March which ran 2.5 to 4
degrees colder than normal, more unusually chilly temperatures are
expected the first half of the coming week.
Surface low pressure should develop Monday along a front stalled
across northern Florida. There are still timing differences among
the various models with how quickly this low moves northeastward
once it develops, but the trend versus yesterday has been slower.
Rain developing Monday afternoon should linger into Monday night and
even into Tuesday along the coast if the low is as slow as the
latest model consensus. The old 00Z ECMWF run was very fast taking
the low out to sea, but we`re moving away from that idea toward a
slower solution as shown on most of the 12Z models including the new
ECMWF. PoPs have been bumped up to 30 percent Tuesday, but given how
even the 12Z GEFS members are now showing the slower movement that
the operational runs did, those PoPs will probably need to be
increased.
The cold upper trough should remain across the area Wednesday with
highs running nearly 10 degrees below normal. Surface high pressure
should reach the Carolinas Wednesday night or Thursday, moving
offshore Thursday night. Friday should warm rapidly with
southwesterly return flow behind the departing high.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
As of 00Z...VFR this evening with south-southwest winds, gusty at
times at the coastal terminals through the overnight hours.
Confidence is increasing for tempo MVFR cigs to occur overnight all
terminals. By the pre-dawn hours showers will develop along the
coast. Will indicate vcsh as most activity should be offshore. Could
be an infrequent rumble of thunder. These move further offshore
along with the MVFR cigs in the early morning.
Low pressure will move east along a frontal boundary situated
between the terminals Saturday. Showers/MVFR cigs will approach the
inland terminals by mid-morning and spread east to the coast late
morning. Best chance of thunderstorms will be coastal terminals
around noon. IFR will become likely in the afternoon all terminals.
Winds will be southwest in the morning becoming highly variable by
afternoon depending on the track of the low.
Extended outlook...Sun MVFR becoming VFR early. Mon VFR/tempo MVFR
SHRA. Tue MVFR/scattered SHRA.
&&
.MARINE...
NEAR TERM /THROUGH SATURDAY/...
As of 900 PM Friday...Gale Watch and SCA all waters daylight Sat
thru much of Sun. Applied latest obs/trends to the consensus 18Z
wind fcsts from various models. Tonights conditions will atleast
be tolerable but will go downhill fast by and after daybreak Sat
and into the short term period.
Previous......................................................
As of 630 PM Friday...Just a quick mid-cycle update to raise a
Gale Watch for Saturday night through midday Sunday. The
expiration time is probably too generous and suspect any Gale
Warnings will not quite last that long. Wanted to give mariners
a heads up for what could be an intense albeit short-lived
window of strong winds.
As of 300 PM Friday...Southerly flow will increase
today as the center of the high moves farther off the Hatteras
coast. Gusty south to southwest winds will continue to increase
overnight as cold front drops south and low pressure develops
and deepens along it before crossing the local waters Sat eve. A
Small Craft Advisory was issued for strong winds and increasing
seas Saturday.
Seas 2 to 3 ft will increase to 3 to 5 ft by Sat morning and
will increase further as gradient tightens with approach of cold
front and deepening low on Saturday. SW winds Sat will shift
to the N Sat eve. Seas should reach 5 to 7 ft through Sat aftn.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 300 PM Friday...Ugly conditions in store for most of the
period. Low pressure to pass by just inland from the coast first
thing Saturday night. Expect solid Advisory conditions but
there is concern regarding a 60kt jet that develops at
925mb/2500ft. The airmass in place will be warmer than the SSTs
and so vertical mixing may be difficult. But given that synoptic
scale wind field so strong there may be ample turbulent mixing
for gale-forced gusts. The threat for such winds is only very
brief as strong cold advection pushes this jet well offshore by
midnight; the subsequent wind fields nowhere near as strong.
Advisory level conditions likely to drop out some time around
midday Sunday as chilly high pressure builds in easing the
gradient rather quickly.
LONG TERM /MONDAY THROUGH TUESDAY/...
As of 300 PM Friday...Low pressure will develop along the
Georgia coast during the day Monday. Models continue to have
timing differences with how quickly the low moves near the
coast, but all models now show the low remaining just off the
coast. This should result in easterly winds backing around to
the north as the low moves past. North to northwest winds should
continue through Wednesday as the front moves offshore and high
pressure builds in from the west.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...Gale Watch from Saturday evening through Sunday afternoon for
AMZ250-252-254-256.
Small Craft Advisory from 8 AM to 8 PM EDT Saturday for AMZ250-
252-254-256.
&&
$$
SYNOPSIS...RGZ
NEAR TERM...DCH/RGZ
SHORT TERM...MBB
LONG TERM...TRA
AVIATION...MRR
MARINE...
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1054 PM EDT Fri Apr 6 2018
.UPDATE...
Issued at 1054 PM EDT FRI APR 6 2018
The cold front has made it as far southeast as a line from Sandy
Hook to Stanton, with light precipitation starting to fill in
better within the vicinity of the front. Temperatures are down
into the lower 40s just behind the front, with 30s on the
doorstep. Have freshened up the POPs and temperatures through the
overnight, incorporating the latest trends in observations. Have
left the rest of the forecast intact. Updates have been sent.
UPDATE Issued at 905 PM EDT FRI APR 6 2018
The surface cold front is currently located just southeast of a
line from KFGX to KSDF to KPAH. Meanwhile, light precipitation has
moved in from the Tennessee Valley, currently affecting locations
mainly along and south of the Hal Rogers Parkway and Highway 80
corridors, as a passing mid-level short wave trough and upper
level jet streak lend support. The forecast generally remains on
track tonight. Did adjust the POPs into tomorrow, given the latest
forecast guidance. This allows for a bit of a lull at times, as
support arrives intermittently. The approach of the colder air
is also trending a bit slower. The latest RUC forecast soundings
reveal a more uniform cooling of the lower atmosphere with time,
likely keeping the sleet more limited. Either way, ground
temperatures will be tough to overcome, given the highs in the
mid to upper 60s from earlier today. Have maintained the amounts,
generally ranging from around a half inch, to as much as 2 to 3
inches in the southeastern terrain, mainly accumulating on grassy
and elevated surfaces. Updates have been sent.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 316 PM EDT FRI APR 6 2018
Current conditions across the area feature increase in cloud cover
across the area. Models have missed quite significantly on the
high temperatures today as they soared into the mid 60s today.
This likely will take a toll on the snow amounts for tonight and
this is showing already with the forecast. Heading into tonight,
there was a slightly further south jog with the system taking
with it a good chunk of the heavier QPF. Will still expect the
colder air filtering in from the north tonight as the precip will
change from a liquid to a brief period of sleet in transition
before going to all snow overnight. The warm layer looks to be
about 1 degree celsius so this will lead to a sleet period in
transition. Would not expect freezing rain during this transition.
In fact the transition will be quick so sleet accumulation will
be minimal. In fact the snow ratios are a bit lower as well. Thus,
will expect around 1 to 2 inches in most locations, especially
the ridges. A local 3 inch is possible but mainly on the highest
ridges. Impacts to roads will be present but likely very local due
to the warm ground. In short, warm daytime temps and less QPF due
to a more southerly track has lead to less impacts than previously
forecast.
Heading into the day on Saturday, the colder air filters more into
the area but the slightly warmer daytime temps will lead to a mix
with snow and rain in the afternoon. Saturday night, the cloud
cover clears out quickly as high pressure moves back into the
area. This will lead to temps plummeting into the lower 20s. This
will lead to a hard freeze Saturday night. Will mention this in
the HWO but will hold off on the NPW as a Winter Weather Advisory
is out right now.
.LONG TERM...(Sunday through Friday)
Issued at 300 PM EDT FRI APR 6 2018
The extended period will be fairly active. The period will begin
with a hard freeze across eastern Kentucky, as temperatures are
expected to bottom out in the lower 20s across the area early Sunday
morning. After a dry day on Sunday, an area of low pressure is
progged to move across the Ohio Valley region. This system will is
expected to bring rain and a bit of snow to eastern Kentucky Sunday
night through Monday morning. Any snow accumulations should be very
light. The precipitation will transition over to all rain by Monday
afternoon, with any lingering showers moving out of the area by
early Monday evening. We may see a few rain showers in the far east
on Tuesday, as a weather system moving up the east coast sends
moisture our way. A period of dry weather is then expected for
Tuesday night, Wednesday, and most of Wednesday night, as a ridge of
high pressure is forecast to build across the region. Another area
of low pressure may then bring some rain back to eastern Kentucky
Thursday and Thursday night. Another round of widespread may occur
late Tuesday night into Wednesday morning, as skies clear off and
winds go near calm across the area.
Temperatures across the area are forecast to be below normal during
the period, with highs ranging from the 40s on Sunday, to the 50s
Monday through Wednesday. It appears, for the moment at least, that
a return to spring like weather, and perhaps above normal
temperatures, will be in store for the end of the week, as highs are
forecast to max out in the 60s and 70s on Thursday. Nightly lows
will be in the 30s and 40s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 905 PM EDT FRI APR 6 2018
An approaching cold front and upper level disturbance will bring
widespread precipitation to the area tonight into Saturday. Light
rain will overspread from southwest to northeast, with
precipitation eventually filling in across the northern half of
the area during the overnight. MVFR conditions will deteriorate
to IFR, as precipitation transitions from rain to snow from
northwest to southeast between 06 and 12z. IFR conditions will
hold on through the early afternoon, before precipitation tapers
off from west to east between 18 and 00z, with an improvement to
MVFR. Southwest to west winds of around 10 kts, with gusts of 15
to 20 kts at times, will shift to the northwest and eventually
north northeast as the front pushes southeast across the area
through Saturday.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 10 AM EDT Saturday for KYZ044-
050>052-058>060-068-069-079-080-104-106>109-111-112-114.
Winter Weather Advisory from 4 AM to 2 PM EDT Saturday for
KYZ086>088-110-113-115>120.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...SHALLENBERGER
LONG TERM...AR
AVIATION...GEOGERIAN
Area Forecast Discussion...UPDATED
National Weather Service Memphis TN
1008 PM CDT Fri Apr 6 2018
.UPDATE...
KNQA radar showed a cold front along I-40 at 10 pm, preceded by a
prefrontal boundary dropping through north MS. Scattered areas of
drizzle and light rain prevailed near these boundaries, while
more widespread light rain was lifting east out of northeast MS.
Latest runs of the HRRR and RAP model showed only light (generally
less than 0.05 inch) post frontal precip north of I-40 overnight.
Newly-arrived 00Z NAM concurred. In any case, some of this light
precip will likely occur with surface temps at freezing, most
likely over northeast AR. Given the marginal confidence in
accumulations occurring, will hold off on a Winter Weather
Advisory and let the updated Special Weather Statement stand.
Regarding other headlines, a Freeze Warning was issued earlier,
matching with areal outline of forecast lows.
Post frontal winds during the early overnight period will be near
Wind Advisory criteria, mainly over the delta. Opted to keep the
non-precipitation headlines simple and hold off on a Wind Advisory
at this time. 10 PM surface obs showed wind speeds prevailing
below advisory criteria with the possible exception of the
typically-windy Blytheville airport.
PWB
&&
.PREV DISCUSSION... /issued 702 PM CDT Fri Apr 6 2018/
DISCUSSION...
Updated for aviation discussion
PREV DISCUSSION... /issued 307 PM CDT Fri Apr 6 2018/
Skies are cloudy across much of the forecast area this afternoon
with temperatures ranging from around 50 degrees to the lower 60s.
A large area of light to moderate rain continues to move across
mainly southern sections of the forecast area. The rain is ahead
of a cold front which currently runs northeast Ohio through
southeast Missouri and into northwest Texas.
The cold front will continue to push slowly southeast tonight with
more rain expected to develop ahead of the front this evening.
SOme thunderstorms are expected to develop into central
Mississippi this evening but should remain south of the forecast
area. Temperatures will turn colder behind the front. There is
still a possibility of a wintry mix over northern sections of the
forecast area toward morning with only minor accumulations
possible.
By Saturday, the cold front will be just south of the forecast
area so some light precipitation is expected in the morning.
Temperatures will be well below normal with highs on Saturday in
the 40s. High pressure will settle into the region by Saturday
night which allow skies to clear and temperatures to be quite cold
for early April. Most locations will see temperatures at or below
freezing by Sunday morning. By Sunday, the surface high will be
east of the region allowing winds to shift to the south and
warming things up some. Highs on Sunday will not be as chilly but
will still be below normal with readings in the upper 40s to
around 60 degrees.
Another cold front will approach the region Sunday night bringing
more light rain to the region. The cold front will move through
the region on Monday with more light rain expected. High pressure
will build back into the region by Monday night. This will start a
period of dry weather from Monday night through Thursday night. A
warming trend will also take place during this period. A new
storm system will start to move into the central U.S. by next
Friday bringing a chance of thunderstorms to the region.
ARS
&&
.AVIATION...
Another round of rain is moving across mainly North Mississippi.
Cannot rule out some embedded thunder at KTUP over the next
couple of hours. The rain will continue to shift east through the
evening. A cold front is just starting to move into the area and
will sweep through over the next few hours with very gusty N/NNE
winds and MVFR cigs. Later tonight a round of light precipitation
should move across mainly northern sections which could change to
a mix...most likely at KJBR. MVFR cigs should prevail through the
morning before improvement areawide during the afternoon.
SJM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Freeze Warning from 1 AM to 9 AM CDT Saturday for Clay-Craighead-
Greene-Lawrence-Mississippi-Poinsett-Randolph.
MO...Freeze Warning from 1 AM to 9 AM CDT Saturday for Dunklin-
Pemiscot.
MS...None.
TN...Freeze Warning from 1 AM to 9 AM CDT Saturday for Dyer-Gibson-
Henry-Lake-Lauderdale-Obion-Tipton-Weakley.
&&
$$
Area Forecast Discussion
National Weather Service Marquette MI
739 PM EDT Fri Apr 6 2018
.SHORT TERM...(This evening through Saturday)
Issued at 356 PM EDT FRI APR 6 2018
WV imagery and RAP analysis indicated a deep mid/upper level trough
from New Foundland into nrn Ontario resulting in cyclonic nw flow
into the nrn Great Lake. A tight sfc pres gradient between low pres
east of Georgian Bay and a 1036 mb arctic high into the nrn plains
was also drawing in plenty of very cold air into the region on gusty
northwest winds. Despite decent instability with 850 mb temps to
around -18C, the LES and diurnally supported land snow showers have
diminished this afternoon as much drier air (dewpoints to -5F
upstream of Lake Superior) filters into the area.
Tonight, the loss of daytime heating/mixing should allow the LES to
better organize and intensify. With inversion heights ranging from
4k-5k ft west to around 6k ft downstream of the longer fetch into
the east, expect snowfall amounts of only an inch or two west but up
to 3 inches in northeast Upper Michigan. Expect enough clearing and
diminishing winds for temps to drop toward the lower end of guidance
inland west to the low single digits but remain in the teens where
LES/clouds persist.
Saturday, sfc ridging and drying will move in more strongly over the
west with lingering LES in the morning diminishing by afternoon with
little additional accumulation. WNW winds into the east may still be
able to produce another inch or two, mainly ene of Munising with an
inch or less to the south. The cold air will remain entrenched,
though with highs still well below normal, in the mid 20s to around
30.
.LONG TERM...(Saturday night through Friday)
Issued at 404 PM EDT FRI APR 6 2018
Another week of temps at or below normal is ahead, with off and on
chances for precipitation through the extended period. A few
lingering lake effect snow showers will be diminishing through the
early morning hours on Sunday as sfc high pressure begins to build
in and temperatures warm up enough aloft to shut it down. The high
will be short-lived, however, as a weakening shortwave and
associated sfc trough skirts through southern WI on Monday, bringing
a chance for some light snow, perhaps mixing with rain south-central
in the afternoon. Likely only a dusting of accumulation, but
possibly up to an inch.
Surface high pressure will dominate the central Plains and mid-
Mississippi valley Tuesday into Wednesday that will help keep us
mostly dry, however a trough passing to our north could bring a few
light snow showers to the northern half of the UP early Wednesday
morning. Should see a bit of a warm up on Wednesday with highs
reaching the low 40s south.
Better chances for precipitation will hold off until Wednesday
night/Thursday morning when a clipper will pass through. At the
current time, it looks to bring enough cold air with it to keep
everything in the form of snow, but it is rather progressive and
would likely only drop a couple of inches
Eyes will be looking closely at Friday and beyond. Models are
indicating the potential for a strong low to move through the
plains, although it will weaken as it pushes towards the Great
Lakes. WAA/Fgen well ahead of sfc low could lead to mixed precip
event based on current deterministic GFS. Though ensemble spread is
rather diverse, most members bring at least some precip to the area.
EC/CMC also have differing solutions as well. Something to keep an
eye on, as currently this would be the most significant weather
event in the extended period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 739 PM EDT FRI APR 6 2018
Unseasonably cold air flowing across Lake Superior on w to nw winds
will lead to lake effect stratocu and -shsn during this fcst period.
Winds gusting to 25-30kt at KCMX will maintain MVFR vis in BLSN this
evening. BLSN will diminish overnight though periodic flurries/-shsn
should develop. CIGS will fall to MVFR overnight, then lift to VFR
Sat aftn. At KIWD, MVFR cigs and flurries/-shsn should develop later
this evening. MVFR cigs will then lift/scatter out Sat aftn. At
KSAW, downslope wind will likely maintain VFR conditions thru the
night. With daytime heating Sat morning, MVFR cigs may develop for a
time before lifting to VFR in the aftn. Winds at all terminals will
be gusty again on Sat, but not as strong as today. Expect gusts to
20-30kt, strongest at KCMX.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 356 PM EDT FRI APR 6 2018
Gales over ern Lake Superior, supported by a strong gradient between
a nrn plains arctic high and low pressure east of Georgian Bay will
linger into this evening. As low progresses eastward, winds will
gradually begin to relax into the weekend as the plains high
pressure starts to build into the area. Initially, tonight winds
will diminish to 20 to 30 knots, and then further diminish to less
than 15 knots by Sunday. Early next week, winds still look like they
will remain at or below 20 knots.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning until 11 PM EDT this evening for LSZ249>251-265>267.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...KCW
AVIATION...Rolfson
MARINE...JLB
Area Forecast Discussion
National Weather Service San Francisco Bay Area
853 PM PDT Fri Apr 6 2018
.SYNOPSIS...A classic atmospheric river will continue to impact
the Bay Area tonight into early Saturday, bringing periods of
heavy rainfall. Drying conditions will develop late Saturday and
Sunday. Rain chances return Tuesday with additional rain chances
later next week.
&&
.DISCUSSION...As of 8:50 PM PDT Friday...A late season Atmospheric
River event has already brought significant rainfall to the Bay
Area, especially the North Bay, since rain began about 24 hours
ago. Several of the wettest locations in the North Bay have
already picked up between 5 and 6 inches of rain including
Occidental, Bodega Bay, Mill Valley, Venado, and Mount Tamalpais.
Downtown San Francisco`s storm total thus far is 1.93" (as of 8
pm), which exceeds the average rainfall for the entire month of
April (1.46") in downtown SF.
Smaller rivers and streams in the North Bay rose rapidly today and
some reached bankfull late this afternoon. A flood advisory has
been in place across much of south-central Sonoma County since
midday, including Sebastopol, Rohnert Park and Petaluma. A Flood
Watch remains in effect for the entire North Bay until Saturday
morning. There has been a lull in precipitation across the North
Bay since mid afternoon and this has allowed small rivers and
streams to recede a bit. However, rain rates are expected to
increase once again by late this evening and into the early
morning hours of Saturday as a cold front approaches the coast.
It`s possible we could see some of the heaviest rain rates of this
event overnight as the cold front provides the necessary lift to
convert the rich supply of water vapor into precipitation. The NAM
and HRRR models indicate the heaviest rainfall in the North Bay
will occur between about 10 pm and 4 am. An additional 1-2 inches
of rain is likely across the North Bay overnight. Anyone living
in flood prone areas of the North Bay, or near the recent burn
scars, should remain alert for possible flood warnings overnight
as this final period of heavy rain triggers renewed rises on small
streams and creeks and possibly triggers debris flows. The models
agree that rainfall will end rather abruptly after the front
moves through. This means that rain should end across most of the
North Bay by sunrise Saturday.
For locations from San Francisco southward, latest models
indicate the heaviest rain will occur between about 2 am and 8 am.
Rain rates will likely be heaviest over the Santa Cruz Mountains,
so will keep the Flood Watch going there. However, rain totals
thus far in the Santa Cruz Mountains are at about 2 inches max,
which is significantly less than what`s fallen in the North Bay.
Thus, flooding concerns in the Santa Cruz Mountains are somewhat
lower tonight than in the North Bay. Nuisance flooding of low
lying and flood prone areas is possible almost anywhere overnight
and into early Saturday morning.
Winds have not been much of a factor with this system, and latest
WRF output indicates wind gusts of no more than 30 mph overnight.
Models agree that rainfall will end in most areas by midday
Saturday. The 00Z NAM indicates isolated showers on Saturday
afternoon but for the most part Saturday afternoon is shaping up
to be mostly dry and mild under partly cloudy skies. Dry
conditions, along with a warming trend, are then forecast for
Sunday and Monday as an upper ridge builds over California.
Forecast highs by Monday are in the 60s near the ocean and 70s to
near 80 elsewhere.
Longer range models indicate the weather pattern will remain
active across the Eastern Pacific and rain chances will return to
the northern portion of our forecast area on Tuesday. A system
closely following the Tuesday system is expected to dig farther
south and possibly bring rain to much of our area by late
Wednesday or Wednesday night.
&&
.AVIATION...As of 5:20 PM PDT Friday...MVFR with areas IFR/LIFR
tonight into Saturday morning. A highly anomalous, exceeding April
climatology, subtropical/tropical air mass is firmly entrenched this
afternoon, dewpoints are near 60. 1/4 mile visibility in fog (and
rain) at the Farallon Islands shows how much the air is "sweating"
while in contact with cooler water, not the other way around
whenever there`s a heat and moisture flux from ocean to cooler air
above. Decided to generally lower cigs and visibilities a little
from inherited forecasts. Conditions improve after cold frontal
passage Saturday morning, best estimate is that frontal passage will
be near 12z. Downpours will increase with the approaching front,
will continue to watch radar and satellite for any signs of isolated
convection and amend tafs as needed.
Vicinity of KSFO...MVFR with SE winds occasionally gusty to near
20 knots persisting into the late evening. Tempo SE winds gusting
close to airport weather warning strength criteria (35 knots
sustained and/or gusts) 10z-16z Saturday, will wait on issuing
weather warning for now and monitor nearby observations to see how
winds are doing through the evening.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Conditions will continue to deteriorate
through this evening, SE winds increasing prior to cold frontal
passage Saturday morning. MVFR to IFR/LIFR forecast for tonight
into Saturday morning, conditions improving by late morning and
afternoon.
&&
.MARINE...as of 4:48 PM PDT Friday...A strong late season storm
system will bring moderate to locally gusty south to southwest
winds and steady rain to the coastal waters into Saturday. Winds
will veer west to northwest in the wake of a cold front passing
through the waters. West swells will increase and create hazardous
seas beginning tomorrow afternoon through the remainder of the
weekend.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...Flood Watch...Entire North Bay and Santa Cruz Mountains
SCA...SF Bay
SCA...Pt Reyes to Pigeon Pt 0-10 nm
SCA...Pigeon Pt to Pt Pinos 0-10 nm
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
SCA...Pt Arena to Pigeon Pt 10-60 nm until 9 PM
SCA...Pt Arena to Pt Reyes 0-10 nm until 3 AM
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm until 3 AM
&&
$$
PUBLIC FORECAST: Dykema
AVIATION: Canepa
MARINE: DRP
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Area Forecast Discussion
National Weather Service New York NY
935 PM EDT Fri Apr 6 2018
.SYNOPSIS...
A cold front moves across the area tonight. The front will stall
offshore on Saturday with multiple areas of low pressure
moving along it through Saturday night. High pressure builds
across the region Sunday through Monday. Another low pressure
will impact the area Tuesday. High pressure returns Wednesday
and Thursday. A cold front may approach the region late on
Thursday into Friday.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Latest surface analysis indicates the triple point is located
across northeast PA and just W of the CWA. The cold front is
draped SW into eastern PA with the warm front across central CT.
The whole frontal system will continue sinking S and E tonight
and should be offshore around 06z.
Temperatures will remain steady or slowly fall this evening and
then drop quicker once the front moves offshore.
Still expecting to see a few showers later tonight as the cold
front moves through although coverage looks limited. Colder air
advecting behind the front may transition a few showers to snow
showers across the interior before day break. May see portions
of Long Island grazed by a wave developing on the front towards
day break so have kept likely PoPs there for now. However, this
may be overdone as the HRRR continues to indicate much of the
precip stays offshore.
Lows are forecast to be mainly in the low to upper 30s.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
The cold front will move offshore Saturday where it will stall.
Chances for snow showers end in the morning. It will be far
enough offshore to allow for one weak wave of low pressure
traveling northeast along it, to keep precipitation south of the
region for the rest of the day. Mainly dry conditions are
anticipated. Colder airmass across the region with 850mb
temperatures about 10 degrees less than the previous evening, -5
to -8 degrees C. Mixing down from anticipated top of mixed
layer near 900mb, will make for forecast highs near upper 40s to
near 50.
For Saturday night, another wave of low pressure will move off
the Carolina coastline and travel northeast along the front.
This low will be deepening more Saturday night into Sunday
morning and it will be traveling far enough offshore to just
brush the Eastern half of Long Island with a chance of snow with
less than an inch. If the low tracks farther NW, then the
chances of snow would increase across the region and snow
amounts will trend higher as well. If the low tracks farther SE,
then the chances of snow would decrease across the region and
snow amounts would be less. Most models take this track by
Sunday morning well south of the 40N/70W benchmark. Will need to
watch and monitor trends as there will be a negatively tilting
trough and upper level jet becoming more meridional Saturday
night into Sunday. Lows Saturday night are forecast to range
from the mid 20s to low 30s.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Cold and dry conditions expected on Sunday as Canadian high
pressure builds across the area. Temperatures will be below
normal with highs in the low to mid 40s and lows in the 20s to
around 30. Quiet conditions will continue on Monday as high
pressure remains in control then slides off the east coast late
on Monday with temperatures continuing to be below normal. A
weak low pressure then moves through the region bringing a
chance for light precipitation across the area on Tuesday and
into early Wednesday morning. Temperatures on Tuesday and
Wednesday will remain below normal for this time of year. High
pressure builds back on Wednesday and Thursday with another cold
front moving through Thursday night into Friday.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
A cold front will approach this evening and move through around
or just after midnight, with winds shifting NW. Winds will be
right around 310 true late tonight and Saturday morning.
Mainly VFR, with a brief period of MVFR conds possible with
precipitation accompanying and following the cold frontal
passage tonight into early Sat morning.
...NY Metro Enhanced Aviation Weather Support...
Detailed information, including hourly TAF wind component forecasts,
can be found at: http:/www.weather.gov/zny/n90
KJFK TAF Comments: G20KT possible late tonight into Sat AM.
KLGA TAF Comments: G20KT possible late tonight into Sat AM.
KEWR TAF Comments: G20KT possible late tonight into Sat AM.
KTEB TAF Comments: G20KT possible late tonight into Sat AM.
KHPN TAF Comments: No unscheduled amendments.
KISP TAF Comments: G20KT possible late tonight into Sat AM.
.OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY...
.Saturday night-Monday...VFR.
.Monday night and Tuesday...MVFR conds possible with a chance
of rain. May start as a mix of rain and snow inland Mon night.
.Wednesday...VFR.
&&
.MARINE...
SCA conditions will continue on the ocean tonight. Winds may
drop off briefly as the front moves offshore, but should see
gusts near SCA levels into the morning.
SCA seas will continue through Saturday morning west of Moriches
inlet and linger into Saturday evening east of Moriches inlet.
SCA level winds are briefly forecast for the ocean waters
Saturday night into early Sunday.
Seas and winds will fall below SCA levels on Sunday thereafter
and remain generally below SCA conditions through the middle of
the week.
&&
.HYDROLOGY...
No hydrologic impacts are anticipated through next Thursday.
&&
.EQUIPMENT...
NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) remains off
the air.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until noon EDT Saturday for ANZ353-355.
Small Craft Advisory until 10 PM EDT Saturday for ANZ350.
&&
$$
SYNOPSIS...Fig/JM
NEAR TERM...JM/DS
SHORT TERM...JM
LONG TERM...Fig
AVIATION...Goodman
MARINE...Fig/JM
HYDROLOGY...Fig/JM
EQUIPMENT...
Area Forecast Discussion.
National Weather Service Raleigh NC
1048 PM EDT Fri Apr 6 2018
.SYNOPSIS...
A cold front is expected to move into NC from the north Saturday
morning. Low pressure will track east along the front as it
moves into southern and coastal NC Saturday. Cold high pressure will
follow the front Saturday night through the weekend.
&&
.NEAR TERM /TONIGHT/...
As of 1045 PM Friday...
Lots to deal with forecast-wise during the next 36 hours, including
1) an expanding area of showers, and probable development of
elevated thunder roughly from FAY to GSB/RWI and points sewd
overnight into Sat morning, 2) widespread rain and marked
CAA/howling nly winds Sat, and redevelopment of storms early Sat aft
in the same general vicinity as those that are expected late
tonight, 3) a brief changeover to sleet and snow over the nrn
Piedmont and nrn Coastal Plain early Sat night, with the potential
for a coating on elevated surfaces, and 4) possible freezing
temperatures Sat night.
WV satellite imagery depicts a relatively pronounced srn stream
perturbation now over the mid-South, which is forecast to deamplify
to the srn middle Atlantic coast through 12Z Sat. A related low
level (850-925 mb) mass response will cause a sswly low level jet to
strengthen while migrating across the sern US, before getting
shunted/veered off the NC coast with the passage of the parent upr
perturbation early Sat morning. Associated warm, moist advection
will yield weak destabilization, up to around 500 J/kg of MUCAPE,
into the Sandhills and srn and cntl Coastal Plain in the several
hours centered around 09Z Sat.
At the surface, a quasi-stationary front was analyzed at 02Z from a
1003 mb low near Waco, TX ewd across nrn LA and s-cntl MS, then newd
across cntl Al, n-cntl GA, and the wrn Carolinas. This boundary will
become increasingly well-defined, while settling sewd into cntl NC
tonight, owing to the aforementioned expansion of showers --and
strong evaporational cooling courtesy of the residual continental
air mass (sfc dewpoints initially in the 30s-40s)-- across the
Piedmont. Associated fgen will further augment ascent and the
probable development of elevated convection over the sern half of
cntl NC late tonight-early Sat. The elevated nature of the
convection and lack of more appreciable instability suggests this
convection should remain sub-severe, provided it indeed
materializes. The pattern described above, and recent runs of the
HRRR certainly indicate it will.
A second front, the one critical for the cold air and probable brief
changeover to frozen pcpn over the nrn Piedmont early Sat night, was
analyzed from very near the lead front over n-cntl TX, then newd
across cntl AR, cntl TN/KY/WV/MD, and sern PA, to a 1004 mb triple
point low over nrn NJ/sern NY. This front is forecast to surge swd,
in backdoor fashion, into srn VA by 12Z Sat.
Low temperatures tonight are expected to fall to near current wet
bulb values, and be driven primarily by diabatic cooling from the
expanding area of showers (and storms over the sern counties) - low
50s north to upr 50s southeast.
Given the lagging and phased nature of the upr trough forecast to
pivot east across the srn middle Atlantic states Sat night, and
related probable secondary maximum of ascent/uvv after dark, when
thermal profiles will be cooling abruptly, the forecast has been
updated to include a light frozen coating/accumulation of up to a
few tenths of an inch on elevated surfaces, north of I-85/40.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 240 PM Friday...
Models continue to bring a wet and even story (SE zones) system
across the region Saturday and Saturday night. The trends in the
models and analyzed data is for a slower push of the cold air in
from the north. This is due to the unseasonably cold parent surface
high pressure is over the upper midwest. This will result in the
Appalachians blocking the cold air initially Saturday from surging
deep into NC as the backdoor front will get held up by the weaker
high. In addition, models are a bit stronger with the mid level
system as it moves from the Tennessee Valley east across the
Carolina`s Saturday. This in turn has led to a stronger low pressure
and a track further north. The mid level will be warmer as well,
with the cold air now expected to be delayed until very late day or
evening (when the main precipitation shield) will begin to push out
of the region. This will lead to several important changes to the
current forecast for the event Saturday and Saturday night.
1. There is now a chance of thunderstorms in the forecast along the
surface low track, mainly along and south of the cold front. Some
elevated thunder will be possible back in the cold air to the north
and west of the front as well. We will add that to the forecast. The
front should come south-southwest through the Triad and Triangle
areas between 14z and 18z, essentially keeping the severe threat
south of these areas. Then the developing surface wave is forecast
to track east from the southern Appalachians to near Fayetteville by
late afternoon. It is the region that will be in the warm sector
longer (areas from Laurinburg to Fayetteville to Goldsboro) that
will have a chance of severe weather between 18z and early evening
Saturday. However, this threat appears to be marginal at the current
time due to the lack of heating (considerable clouds, MLCAPES rather
meager of less than 1000 joules, and limited height falls). But the
wind shear current forecast supports organized convection and the
small damaging wind gust threat along or near the low track. We will
add this to the Hazardous Weather Outlook (HWO). The threat will end
quickly by around or before 00z or 800 PM as the front slips south
of the entire area.
2. The threat (if there ever was one) of wintry weather is
decreasing. The track of the low closer to our region has increased
mid level temp forecasts through much of the main precip event
Saturday afternoon and evening. Even near sunset Saturday, forecast
partials have the mid levels too warm for anything but rain (even at
Roxboro and Winston-Salem). The cold nose is very cold at the same
time, with some numbers forecast near 1290m at Roxboro by this time.
That suggests some potential for a little sleet (non-event) and
light freezing rain may mix in. However, wet bulb forecasts strongly
suggest that freezing rain will not be an issue given the forecast
wet bulbs in the mid 30s at that time at Roxboro and the Triad, 40
at RDU, and 50 at Fayetteville. Since the main precipitation will be
tapering off and ending between 00z and 03z/ or mid to late evening,
no winter weather impacts are expected. Rain may briefly mix with a
little sleet or snow at the end of the event, with no accumulations
expected. Even if more snow/sleet end up occurring along and north
of Interstate 40/85, the ground/roads are warm and it will be
difficult to accumulate.
The northern zones including the Triad and Triangle will see falling
temperatures and rain beginning at 14z-18z, with readings starting
near 60, falling into the mid 30s by sunset. Areas to the south
will see falling temps in the afternoon, with near 70 at noon -
falling into the lower 40s by Sat. evening.
We do expect rain, heavy at times with QPF of 0.75 to 1.25 (maximum
along the track or just north of the track of the surface wave on the
cool side of the boundary).
Clearing and breezy conditions very late at night should lead to very
little time for a freeze to occur in the east. However, the western
Piedmont may be more susceptible to a freeze if clearing occurs in
time and if the winds die off some. It is hard to get a freeze with
purely CAA this time of year. We will hold off on a Freeze Watch for
the 3rd period, and keep mention of possible freeze in the HWO over
the Piedmont. Lows should stay 33 or above east and south of RDU,
with 30-35 in the Triad.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 230 PM Friday...
Any lingering cloudiness in the Coastal Plain early Sunday will
quickly give way to sunny and dry, but cold conditions thanks to NW
flow as the upper trof axis shifts offshore. It will be quite cool
for early April, with highs struggling to reach the mid 50s, which
is 12 to 15 degrees below normal. Cloudiness will be moving in
quickly Sunday night as a fast-moving northern stream short wave
races east across the southern Ohio Valley, moving off the Mid
Atlantic north of the area. Min temperatures will have a few hours
to crash before the cloudiness moves in, falling to mostly mid 30s
north and upper 30s south. On Monday, the moister southern stream is
suppressed south, so PoPs will be limited to chance category. Cool
air remains entrenched and with fairly extensive cloudiness, highs
will stall again in the 50s.
Models are still indicating a southern stream low pressure area
developing off the southeast coast, but details diverge as to how
strong and how near the coast the low passes. As such, PoPs will be
higher in the east. but still only in the chance range at this
point. Our cool airmass remains locked in place, subject to
potential evaporative cooling depending on where the low tracks, so
highs will remain below normal, optimistically low to mid 60s.
Mild high pressure builds in as the low lifts out Tuesday night,
with gradual amplification and eastward progression of a ridge over
the midwest towards the area by late week. Expecting dry and warming
Wednesday through Friday, with mostly low to mid 60s Wednesday
warming to the lower 70s Thursday and upper 70s on Friday.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
As of 730 PM Friday...
24 Hour TAF period: VFR conditions are expected to deteriorate
rapidly overnight as cloud cover increases from west to east. Expect
MVFR CIGS at most sites by daybreak Saturday, with fluctuating
MVFR/IFR/LIFR CIGS and VSBYS through most of the day as widespread
rain showers envelop the region. Have also included Thunder at KFAY,
which has the best chance of seeing some minor heating tomorrow
morning ahead of the main wave of precipitation. Low confidence on
overall timing, so have gradually trended the forecast downward
through the Categories. In reality, the drops will likely be more
sudden, and vary with rainfall intensity over the individual sites.
VFR conditions return Sunday as high pressure builds into the Mid
Atlantic, but will only last through Monday morning as the next
system builds north through the area, likely introducing sub-VFR
aviation conditions to central NC.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Badgett
NEAR TERM...MWS
SHORT TERM...Badgett
LONG TERM...MLM
AVIATION...JJM
Area Forecast Discussion
National Weather Service Tallahassee FL
941 PM EDT Fri Apr 6 2018
.UPDATE...
Chances of showers and thunderstorms have been increased across
much of our area from the overnight period through tomorrow
morning, as CAMs (especially the latest HRRR runs, which have been
initializing fairly well) have tended to bring the convective
complex into our area earlier. Isolated damaging winds still
appear possible on the leading edge of the convection, especially
across our southern areas where around 1000 J/kg of SBCAPE will be
present in addition to around 40 kts of 0-6 km shear. Isolated
tornadoes embedded in the line cannot be ruled out either, as 0-1
km shear from 20-30 kts and 0-1 km helicity around 150 m^2/s^2
will be somewhat favorable. Overnight low temperatures are still
expected to remain in the lower-mid 60s across our area.
&&
.PREV DISCUSSION [745 PM EDT]...
.NEAR TERM [Through Tonight]...
Surface high pressure will weaken tonight as our next system to the
west develops. Ahead of this front expected to move through
tomorrow, low level flow has become southerly with Gulf moisture
returning to the area. A few showers and thunderstorms will be
possible overnight across the western zones, but the main focus for
tonight is a weakening line of storms that is expected to move into
our western counties early Saturday. With CAPE values 500-800 J/kg
and deep layer shear values 40-50 knots, a few strong to severe
storms will be possible across parts of southeast Alabama and the
Florida panhandle as the line of storms moves in. SPC has
highlighted this area in a marginal risk for early Saturday morning.
The main threat is damaging winds. The severe threat will increase
across the remainder of the CWA on Saturday but this is covered in
the short term section.
With the southerly flow and increase in clouds, lows will only drop
into the upper 50s to mid 60s tonight. Patchy fog will also be
possible across our eastern counties tonight, mainly southwest
Georgia and the Florida Big Bend.
.SHORT TERM [Saturday Through Sunday Night]...
A surface low over southeast Alabama Saturday morning will deepen
as it races east-northeastward and off the North Carolina coast
by late Saturday evening dragging a SWWD extending cold front
with it. An extensive area of showers and thunderstorms will
proceed the front and some storms could be strong to severe. SPC
has most of our CWA outlined in a slight risk for severe
thunderstorms with the remainder of the area (northwest) in a
marginal risk. Models continue to show sufficient instability and
shear to support organized convection. The main severe threat
with these storms will be damaging wind gusts but a brief tornado
or two is also possible. PoPs will be likely to categorical
(70-90%) all zones Saturday with rain ending from northwest to
southeast Saturday evening into early Sunday with the passage of
the cold front.
We will see a brief dry period Sunday before the aforementioned
front lifts north as a warm front Sunday night bringing a low end
chance for rain.
.LONG TERM [Monday Through Friday]...
Rain chances continue Monday through at least late Tuesday as
another cold front approaches and passes through our region.
Thereafter, high pressure and a drier airmass return to finish out
the work week.
.AVIATION [Through 00Z Sunday]...
VFR conditions will continue across most terminals this evening
under light southerly flow. One exception will be ECP, where a
broken low cloud deck is providing MVFR cigs. MVFR/IFR cigs will
increase across our area, along with some visibility reductions
during the early morning. Showers and thunderstorms will move
across our area from NW to SE from the morning to early afternoon,
and scattered thunderstorms will remain possible later in the
afternoon.
.MARINE...
Wind speeds will increase to cautionary levels Saturday ahead of a
cold front. Winds may briefly reach advisory levels late Saturday
or Saturday night before diminishing on Sunday. Winds may surge
again around mid-week in the wake of another front.
.FIRE WEATHER...
Moisture will gradually increase across our area through tomorrow
ahead of a cold front, then decreasing Sunday post frontal. RH
values will not reach critical thresholds over the next several
days, therefore no fire weather concerns are expected at this
time.
.HYDROLOGY...
Two frontal systems are expected to bring rainfall to the area over
the next week- one Saturday and one early next week. Each of these
systems will bring around an inch or so of rain, so total
accumulations over the next 5 days will likely be around 2 inches.
These accumulations are not expected to result in flooding along our
area rivers, as they are currently at low levels.
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 63 77 55 73 55 / 20 90 30 10 40
Panama City 67 73 51 70 59 / 40 80 30 10 40
Dothan 63 71 44 69 52 / 80 90 20 10 40
Albany 62 74 46 69 52 / 40 100 20 10 40
Valdosta 60 79 49 70 52 / 10 90 40 10 30
Cross City 60 79 58 75 57 / 10 40 60 20 30
Apalachicola 66 74 54 71 60 / 20 70 40 10 40
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
UPDATE...Lahr
NEAR TERM...Fieux
SHORT TERM...Barry
LONG TERM...Barry
AVIATION...Lahr
MARINE...Barry
FIRE WEATHER...Humphreys
HYDROLOGY...Nguyen
Area Forecast Discussion
National Weather Service Tulsa OK
926 PM CDT Fri Apr 6 2018
...UPDATE...
.DISCUSSION...
Cold air continues to filter south with temperatures currently
around 30-35F across portions of northeast OK. Lead batch of
precipitation has resulted in areas of light sleet and snow with a
few reports of slick roads just over the state line. Have gone
ahead with a short-fuse winter weather advisory for these areas
through 1 am, as HRRR shows this precip weakening into the early
morning hours.
Also watching another area of wintry precipitation across western
and central KS, although latest ARW/HRRR runs gradually dissipate
this activity as it approaches northeast OK late tonight. HRRR as
suggests a more significant band of wintry precip across southeast
OK by Saturday morning, but will allow overnight crew to take a
closer look at this.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 25 45 32 57 / 50 10 10 10
FSM 30 49 33 59 / 40 20 10 10
MLC 29 46 33 59 / 50 20 0 10
BVO 24 45 27 56 / 60 10 10 20
FYV 26 45 25 54 / 60 20 10 10
BYV 26 44 27 53 / 60 20 10 10
MKO 28 46 30 58 / 50 10 10 10
MIO 24 44 27 54 / 60 10 10 20
F10 27 46 31 57 / 40 10 10 10
HHW 36 50 35 62 / 40 20 0 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...Freeze Warning until 10 AM CDT Saturday for OKZ054>076.
Freeze Watch through Saturday morning for OKZ049.
Winter Weather Advisory until 1 AM CDT Saturday for OKZ054>058.
AR...Freeze Warning until 10 AM CDT Saturday for ARZ001-002-010-011-
019-020-029.
&&
$$
SHORT TERM...18