Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/19/17

Area Forecast Discussion

National Weather Service Bismarck ND

 937 PM CDT Tue Apr 18 2017

.UPDATE...
Issued at 936 PM CDT Tue Apr 18 2017

Main change for this update was to delay the onset of
rain chances across southwest ND by a couple hours. The 19.00z NAM
holds off the rain chances until near 19.12z, which is close to
the HRRR timing.

UPDATE Issued at 636 PM CDT Tue Apr 18 2017

Only made small changes to the going forecast to blend in current
conditions. The fog forecast remains a challenge, though the HRRR
and SREF both suggest at least some restriction in visibility
will occur late tonight into early Wednesday morning. The rain
chances for late tonight into Wednesday still look reasonable,
though we may be bringing the chances in a little too quick. Will
take another look, and consider slowing the timing in the next
update.

&&

.SHORT TERM...(This evening through Wednesday)
Issued at 249 PM CDT Tue Apr 18 2017

Weather features as of Tuesday afternoon include a cold frontal
boundary extending from low pressure across Minnesota through
South Dakota. The frontal boundary/baroclinic zone then extends
into Montana in what will remain a quasi-stationary frontal zone.
This will be the focus for increasing chances of rain across the
west and south late tonight and Wednesday.

There is some uncertainty on the potential for fog tonight. On one
hand the cool boundary layer and area of stratus across much of
central North Dakota will be favorable for fog formation as the
stratus erodes this afternoon and evening. This combined with the
abundant low level moisture from the rainfall last night would
increase the likelihood for fog. On the other hand increasing mid
level clouds may tend to inhibit fog. Will favor the fog argument
initially then diminish it late tonight as the clouds increase.

On Wednesday the best chances of rain will be south and west with
the influence of surface high pressure across the northeast
holding off precip chances there.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 249 PM CDT Tue Apr 18 2017

The extended period will be at first mainly dry as h500 fractured
flow/rex blocking across the north central CONUS Thursday and
Friday breaks down to a broad flat ridge by the weekend. This will
support at least near normal to above normal temperatures with
low or no pops until Monday and Tuesday when progressive short
wave energy brings the next chance for rain. Highs will be in the
mid 50s and 60s through the weekend then cooling to the 40s/50s
Monday and Tuesday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 636 PM CDT Tue Apr 18 2017

A few mvfr ceilings remain in place late this afternoon across
central ND. Forecast soundings and numerical guidance still
suggest some improvement, so have gone with that for now. There is
some potential for fog late tonight into Wednesday morning, so
introduced mvfr visibilities overnight. Rain is expected spread
into southern parts of the state on Wednesday, mainly affecting
KDIK, KBIS and KJMS.


&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...CK
SHORT TERM...WAA
LONG TERM...WAA
AVIATION...CK



Area Forecast Discussion...UPDATED

National Weather Service Brownsville TX

 1006 PM CDT Tue Apr 18 2017

.DISCUSSION...A quick look at the latest NAM and HRRR does not
show much in the way of convection developing overnight or around
sunrise, with exception to well offshore. Have cut back on the
pops over night and into Wednesday. With the upper trough axis to
our east and slow filling of the trough would believe best shot of
rain Wednesday would be along the sea breeze. Decreased clouds
cover slightly while the rest of the forecast looks on track.

&&

.PREV DISCUSSION... /issued 707 PM CDT Tue Apr 18 2017/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...Very isolated convection north of KMFE is expected to
weaken/dissipate around or shortly after 01z with the atmosphere
slowly stabilizing as daytime heating wanes. Models suggest a low
probability and short duration of MVFR cigs overnight with
central areas along the 69C/281 corridor seeing the best chances.
Patches of MVFR vsby may develop over the air fields, especially
KHRL and KMFE, due to the wet ground and limited cloud cover much
of the night. VFR conditions prevail Wednesday along with light
southeast winds.

PREV DISCUSSION... /issued 256 PM CDT Tue Apr 18 2017/

SHORT TERM (Tonight through Wednesday Night): Still somewhat
unsettled weather in store for the next 24 hours. Convection has
been slow to initiate early this afternoon due to stabilization in
the wake of the mesoscale convective system that formed along the
coast, and subsequently moved eastward into the Gulf, early this
morning. However, a few cells are popping up in Kenedy County as
of this writing, along what appears to be a sea-breeze boundary,
with the cells moving generally to the SSW. PoP`s from recent
model runs have been much lower (generally 20% or less) through
tomorrow. Have blended in the newer guidance with the going
forecast. Am wary to go too far with cutting rain/thunder chances,
with moisture still in good supply (PW around 1.5"), especially
in the eastern counties. Boundary interactions also still
possible. Not expecting much in the way of severe weather, though
a rogue storm could still produce wind gusts up to 40mph and some
small hail.

Convection should shut down pretty quickly by around sunrise, with a
mainly quiet evening in store.  After midnight, some increase in
"wrap-around" lower-mid level moisture is indicated by both the NAM
and GFS, as the 500-mb low reforms over the western Gulf south of
the border, as it is nudge by upper ridging building across central
TX.  Despite a slug of drier air expected to move in between 700-
500mb, a isolated showers and thunderstorms may occur along the
immediate coast.  Overnight low temps will be in the upper 60s to
around 70.  Can`t rule out some patchy fog for inland areas where
the ground is still wet, but not confident enough to mention in
grids.

For Wednesday, N-NE flow aloft develops on the front side of the
aforementioned ridge, with slow drying taking place at upper levels.
Looks like the plume of low-mid level moisture will hang around at
least through the first part of the day, though, except far west.
With temps along Hwy. 77 rising into the upper 80s, looks like
another pretty decent setup for some sea-breeze convergence around
mid-day. Models are only hinting at this, but went above MOS
guidance PoP`s with the ingredients mentioned. Whatever does develop
would seem to shut down around mid-afternoon, as subsidence aloft
increases. As ridging aloft takes hold and by Wednesday night, rain
chances finally become nil with lows again in the upper 60s to low
70s. Went ahead and put in patchy fog for the Northern Ranchlands as
winds become light and forecast RH`s approach 100%.

LONG TERM (Thursday through Tuesday): Ridging aloft will be
building into the region to start the long term as the shortwave
pulls away. Plenty of mid-level dry air will be in place and with
no expected weather features, the forecast will remain rain-free
both Thursday and Friday. Meanwhile, temperatures will warm into
the mid 80s to mid 90s given lower moisture levels and plenty of
sunshine, with lows still running above normal.

Heading into the weekend, a cold front is progged to quickly drop
south though Deep South Texas sometime late Saturday morning or
into the afternoon. The mid-level storm system and surface low
will pass well to the north, across Oklahoma and Arkansas. As
such, the better upper level support/dynamics will not be in place
and the cold front will be more trailing in nature. Meanwhile,
the mid-levels still appear to be rather dry, with little in the
way as any significant moisture return ahead of the frontal
boundary. However, the front will be moving through during the
optimal daytime heating period. Some showers and thunderstorms
will be possible, but have left them at slight to chance POPs.
The front will move through and exit the RGV by early Sunday with
temperatures noticeably cooler as readings fall back to near or
even a bit below normal to start the new work week.

The cooler temps won`t last long however, as strong surface high
pressure and a ridge of high pressure aloft build in quickly
behind the cold front with temps already rebounding on Tuesday as
dry weather continues.


MARINE:

Now through Wednesday night: The threat of thunderstorms
continues for the coastal waters, mainly later tonight into
Wednesday morning. Gusty winds, locally agitated seas, and perhaps
small hail are possible with stronger cells. Outside of
thunderstorms, SE winds of 10-15 knots and seas of 3-4 feet will
be the rule.

Thursday through Saturday: High pressure over the Northeastern
Gulf will keep light to moderate southeast winds and low to
moderate seas in place through Friday. A cold front will sweep
through the Lower Texas Coastal Waters on Saturday bringing some
chances for showers and thunderstorms. Strong surface high
pressure will build into the region later on Saturday with the
surface pressure gradient tightening and marine conditions
becoming hazardous.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&

$$

This product is also available on the web at:
HTTP://WEATHER.GOV/RGV

59...short term/aviation
58...long term



Area Forecast Discussion...UPDATED

National Weather Service Caribou ME

 959 PM EDT Tue Apr 18 2017

.SYNOPSIS...
A weak frontal boundary bisecting the state will continue to
weaken into early evening. High pressure will build into the
region tonight and move east on Wednesday. A cold front will
pass through state Wednesday night into Thursday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
1000pm Update: Forecast is in good shape, only update was to
trend low temperatures up in a few areas. The stratu-cu cloud
deck is holding on a little longer than expected, should help
insulate some regions of the CWA.

700pm Update: Not much to change in the forecast at this time.
The few instability rain/snow showers have mostly ended across
the area with the stubborn stratus deck holding on across the
area. Dewpoints are trending down, so if once we get some
breaks in the cloud deck later tonight expect temperatures to
drop below freezing across most of the region still.

Drier but continued unseasonably cool for April.

A line of showers were moving across the northern portions of
the CWA this afternoon. This activity was in response to an
upper disturbance moving across the region as seen in the latest
Satl WV imagery. At the sfc, high pres was beginning to ridge in
from the n. Those showers will move se and dissipate later this
afternoon as the upper level feature lifts to the e. Clouds
holding tough this afternoon will gradually thin out by evening
especially across the eastern areas while sits to the w such as
Piscataquis County and the Allagash will hang on to the clouds
longer w/the light ene flow in the blyr. High pres at the sfc
and aloft is forecast to move into the region tonight
w/conditions improving. The soundings data from both the NAM and
GFS show the column to dry out allowing for some clearing. This
is supported by the latest run of the RAP guidance and supported
by the latest visible imagery showing signs of the cloud deck
thinning. The caveat to this will be the clouds across the
ridge axis in Piscataquis County that will hang on for a time
tonight until the flow aloft turns to the sw as the ridge axis
pulls e. Temps across the north and west will drop back in the
mid 20s w/upper 20s to lower 30s elsewhere.

For Wednesday, some sunshine to start the day but clouds will be
on the increase as a cold front approaches the CWA from the
west. Decided to pull back on the arrival of showers til later
in the afternoon as the atmosphere will take some time to
moisten. The NAM and GFS both support this solution as done the
Canadian GEM. Rain showers look like they will arrive into the
western areas by 21-00z timeframe. Continued very cool w/daytime
temps averaging in the 40s.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
Models are in pretty good agreement with bringing a cold frontal
band of rn shwrs...possibly mixed with sleet or wet snow across
Nrn areas Wed ngt with generally 2 to 3 tenths of total QPF
before the event ends Thu morn. Following the front, hi temps
should recover closer to seasonal norms Thu aftn with at least
partial clrg.

But any clrg will be brief with cldnss already xpctd to increase Thu
ngt ahead of a vigorous late Apr s/wv and associated sfc low movg E
from the Great Lks. precipitation from this system will begin as rn
across the region on Fri.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Secondary low pres developing ovr the Gulf of ME Fri ngt will
result in dynamic cooling alf, chgng rn from Fri to wet sn ovr
Nrn and Cntrl ptns of the Rgn by late Fri ngt, with a rn/sn mix
even possible ovr Downeast areas by erly Sat morn with this
process being enhanced by the upper low crossing ovr ME durg
this tm. Sig snfl is possible across spcly higher trrn of
Nrn/Cntrl ptns of the region by mid to late Sat morn, at which
point reduced precip rates and increased background cld filtered
insolation would result in melting snfl and a transition to rn
before precip ends late in the day. Total QPF with this event,
which could reach an inch for ptns of the FA may be somewhat
delayed entering spcly Nrn mainstream river basins if a sig ptn
of the event falls as sn.

Following the exit of the low alg the Srn periphery of of Nova
Scotia by Sat eve, skies should clr across the Rgn by late Sat
ngt, with again sig rebound of hi temps on Sun, likely to melt
any remaining snfl across the region from Sat.

The next chc of any precip in the form of rn/rn shwrs may be on Mon
into Mon ngt ahead of a late season surge of arctic-like air across
Ont and QB with origins from the Canadian Archipelago achieving
unseasonably high max arctic indices of 50 to 55 this weekend
before Swrd modification of the air mass early next week. This
air mass will likely result in below normal hi temps across our
Rgn on Tue despite potential sunshine across the region.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: VFR w/a brief period of MVFR for the northern TAF
sites this evening. VFR for KBGR and KBHB. It looks like VFR for
all sites for Wednesday.

SHORT TO LONG TERM: MVFR/IFR clgs/vsbys in rn Wed ngt across
out TAF sites will transition to VFR on Thu and hold VFR into
Thu ngt. Conditions will then lower to MVFR in rn on Fri and
then IFR Fri ngt with rn chgng to sn spcly across Nrn TAF sites.
IFR conditions should improve to MVFR by Sat aftn at the
conclusion of precip and then to VFR aftwrds Sat ngt and Sun.

&&

.MARINE...
NEAR TERM: No headlines expected. ENE winds becoming SE on
Wednesday w/speeds of 10 to 15 kts w/a few gusts to 20 kts. Seas
will stay 4-5 ft especially for the outer zones into Wednesday.

SHORT TO LONG TERM: TERM: At or below marginal SCA conditions are
xpctd, with a pd of strong SCA winds and perhaps minimal gales
possible later Fri into Fri ngt ahead of secondary low pres forming
ovr the the Gulf of ME. Kept close to WW3 wv guidance for fcst wv
hts for these ptns of the fcst.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.

&&

$$

Near Term...Hewitt/Dumont
Short Term...VJN
Long Term...VJN
Aviation...Hewitt/Dumont/VJN
Marine...Hewitt/Dumont/VJN




Area Forecast Discussion

National Weather Service Cheyenne WY

 540 PM MDT Tue Apr 18 2017

.SHORT TERM...(Tonight - Thursday)
Issued at 235 PM MDT Tue Apr 18 2017

A fast moving and intense upper-level shortwave continues to track
across the Great Basin late this afternoon. This feature is likely
to lift northeast across Utah/Colorado/Wyoming during the evening/
overnight hours with an associated 100+ knot H25 jet punching into
northwest Colorado after 06z Wed. This disturbance will serve as a
focus for convective development as large scale forcing for ascent
continues to increase into the evening. Showers/thunderstorms will
likely become quite numerous over western/northern areas overnight
with strong upper divergence within a coupled upper jet regime and
strong mid-level PVA. Increased PoPs into the 80-90 pct range with
the HRRR consistently showing widespread precipitation coverage. A
less-certain potential for nocturnal thunderstorms will exist over
the western Nebraska Panhandle between 03z-09z on the nose of very
strong low-level WAA. High-resolution models do not show much, but
it is hard to believe we would not see elevated convection w/quite
a few forcing mechanisms at work. If storms form, MUCAPES of 1000-
1500 J/kg and 40+ knot H5 flow would provide the necessary support
for rotating updrafts capable of producing hail. The SPC MRGL risk
makes sense, so we have maintained mention of small hail thru late
tonight. A storm or two may become severe.

The GFS/NAM/ECM are in agreement w/varying degrees of cyclogenesis
over east central Wyoming during the overnight hours w/the low and
associated frontal boundary tracking across western Nebraska early
on Wednesday. This should result in strong low-level gradients. In
fact, the NAM shows a H85/H7 CAG-CPR gradient of 60+ meters during
the 9z to 15z Wednesday time frame. Some concerns for high wind at
ARL because of this, but a lack of stronger flow aloft precludes a
headline at this time. Winds will spread east across the plains in
the afternoon, likely in the 25-35 MPH range w/ gusts around 45 to
50 MPH given the gradients in place and fairly steep lapse low-lvl
lapse rates supported by weak CAA aloft. Dry surface high pressure
appears to be on tap for Thursday, with little/no chances for pcpn
and lighter winds.

.LONG TERM...(Thursday Night - Tuesday)
Issued at 235 PM MDT Tue Apr 18 2017

Widespread rain and showers with some higher elevation snow seen
for Thursday night through Friday as an upper shortwave moves
southeast across the region and interacts with surface upslope
flow. several inches of snow expected over the higher mtns with
mainly rain elsewhere. Weaker second shortwave should keep some
showers going mainly around the mtns Friday night into Saturday.
Rather cool across the CWA Friday with max temps in the 40s over
most lower elevations. Warming again over the weekend along with
mainly dry conditions as upper ridging moves across the area and
deamplifies. Continued mild and dry Monday under a generally zonal
flow. Shortwave scoots by to the north of the CWA Monday with main
effect being some enhanced wind. A few showers could return to the
area by late Tuesday as the next upper trough begins digging over
the western CONUS.

&&

.AVIATION...(For the 00Z TAFS through Wednesday morning)

VFR expected through late this evening with MVFR CIGS and VIS later
tonight into Wednesday morning over the NE Panhandle and near KRWL.
CIGS may be near IFR criteria across portions of the NE panhandle as
well, but confidence is low at this time. Scattered rain showers and
a few thunderstorms will push east into western Nebraska by late
this evening. High resolution models indicate some elevated
thunderstorms developing after midnight, mainly impacting KBFF,
KAIA, and KCDR.

&&

.FIRE WEATHER...
Issued at 235 PM MDT Tue Apr 18 2017

No fire weather concerns over the next few days in anticipation of
a cooler, and somewhat unsettled weather pattern.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&

$$

SHORT TERM...CLH
LONG TERM...RE
AVIATION...TJT
FIRE WEATHER...CLH




Area Forecast Discussion...UPDATED

National Weather Service North Platte NE

 644 PM CDT Tue Apr 18 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 318 PM CDT Tue Apr 18 2017

The upper level disturbance moving through Cntl CA this afternoon
should close off at h700mb across Ern WY by 12z Wednesday morning.
The low would then jog south of the Black Hills and then resume
course moving through SD Wednesday. The result is a period of warm
air advection tonight which should produce showers and thunderstorms
across Nrn Nebraska. A model blend was used for this forecast. The
RAP and HRRR models seem to be too dry given the moisture and
forcing tonight. These models were too conservative with the MCS
which moved through Ncntl Neb Monday night.

The warm air advection and resulting instability/CAPE in the NAM and
GFS models...500 in the GFS to 1750 J/KG in the NAM...will support
thunderstorms. The NAM suggests a few strong to severe storms
capable of large hail.

A Pacific cold front is forecast to move through Wrn Neb Wednesday
afternoon. This should clear out the skies with temperatures rising
into the 60s to lower 70s. Cloud cover across Nrn Neb would hold
highs in the 50s.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 318 PM CDT Tue Apr 18 2017

A storm off the Oregon Coast is progged to move east and drop
through WY Thursday night. The model- track of the storm through
the Cntl High plains and KS Friday varies by about 200 miles. The
NAM...SREF and Canadian solns are north favoring rainfall across
much of Nebraska while the GFS...GEF and ECM are farther south
favoring KS for the best rainfall. The forecast is a blend of
solns at this point which results in a storm track in the middle
of the model envelope. All models suggest likely rainfall across
Swrn Neb.

No thunderstorms are expected with the system. Nebraska will be on
the north side of the upper low and K indices are in the 20s in the
GFS and NAM. No elevated instability/CAPE was indicated in the NAM.

The rest of the forecast is dry. Another storm will track north of
the area Monday but no moisture return was indicated in the wake of
the storm Friday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 638 PM CDT Tue Apr 18 2017

Front lying to south over northwest Kansas tonight with stratus
developing to the north of the front across western Nebraska.
Storm system will move across the Dakotas tonight with
thunderstorms developing over mainly northern Nebraska after 06z.
Some isolated showers in high based aoa 110kft mid clouds moving
over northwest Nebraska early this evening. Maybe some virga. Main
show after midnight and will mainly affect KVTN as upper low moves
across the Dakotas. Showers and thunderstorms to continue into
Wednesday morning with MVFR cigs moving out of western Nebraska
through the afternoon.


&&

.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Power




Area Forecast Discussion

National Weather Service Paducah KY

 749 PM CDT Tue Apr 18 2017

.UPDATE...
ISSUED AT 746 PM CDT TUE APR 18 2017

Looking at the latest HRRR and RAP models, will likely keep small
shower/tstorm chances over parts of west Kentucky overnight. Will
keep the wording as isolated.

UPDATE Issued at 642 PM CDT Tue Apr 18 2017

The AVIATION section has been updated for the 00Z TAF issuance.

&&

.SHORT TERM...(Tonight through Thursday night)
Issued at 325 PM CDT Tue Apr 18 2017

A weak mid level disturbance migrating across KY/TN has resulted in
a few isolated showers and storms close to the TN border. These will
move northeast into portions of west KY thru the afternoon (mainly
southern counties). Other very isolated convection is possible
mainly south and east of Poplar Bluff, MO to Evansville, IN line.
Showers should dwindle in coverage with loss of daytime heating, but
can`t rule out a few affecting the Pennyrile region into the
evening. Mid level ridge axis comes through overnight, allowing for
skies to clear over good portion of the region. Seems to be some fog
potential with the clear skies and light winds in place.

On Wednesday, we will have southerly winds in place ahead of a
developing storm system in the Central Plains. At the same time a
weak ripple in the flow may lead to a few isolated showers and even
a thunderstorm over western KY, with best chance at anything over
southern Pennyrile. Dry conditions are expected Wednesday
evening/night.

A shortwave and associated sfc low moving across the Great Lakes on
Thursday will induce a cold front to push southeast into our area
during the day/evening. While the best dynamics with this system
will be well to our northeast, there looks to be some favorable
ingredients in place, that a few strong storms can`t be ruled out.
Sufficient CAPE and shear will be in place, along with dewpoints
into the low to possibly mid 60s. The front looks to get hung up
just to the south of our area by the end of this period, keeping
rain chances in the picture, particularly for the southern half of
the region.

Temperatures will be quite warm, with many locations into the low
80s both tomorrow and Thursday. Lows will also be mild, around 60
tonight and mid 60s tomorrow night. Cooler temps come in later Thurs
night as northerly sfc winds advect in cooler air.

.LONG TERM...(Friday through Tuesday)
Issued at 325 PM CDT Tue Apr 18 2017

The period will begin with a cold front off to our south over the
Gulf Coast states. However, even with the front well to the south,
it looks as there may be quite a bit of isentropic lift/overrunning
developing north of the front as a potent mid level short wave moves
east into the Southern Plains Friday afternoon/Friday night. Highest
rain chances will be over the west half of the region, though much
of the rest of the area will likely get into the overrunning rain
shield by Saturday morning.

Models are in decent agreement that the sfc low associated with the
short wave will pass to our south Saturday/Saturday evening. This
would keep most of the instability and severe thunderstorm risk
south of the region. Still quite a ways out in time though, so will
need to monitor model trends the next few days. It would not take
too much of a shift north with this system to bring more of a
thunderstorm threat to the region, especially down near the AR/TN
borders.

Biggest impact main come with heavy rain as mid level forcing
increases over the region and PW values rise up close to 1.25",
especially over our southern counties. Could see a good one to two
inches of rainfall in those areas Saturday. Due to the proximity of
the front to our south, will also include a mention of isolated
elevated thunderstorms Saturday afternoon over the south half of the
forecast area.

High pressure will finally settle back into the region by early next
week, bringing dry conditions back to the region. The high will not
be of Canadian origin, however, so temperatures will stay on on the
mild side through the period.

&&

.AVIATION...
Issued at 642 PM CDT Tue Apr 18 2017

Short range guidance indicates that isolated to scattered showers
will linger through much of the evening east of the Mississippi
River. Will leave VCSH in at all sites.

Winds should become calm or very light from the south overnight,
so fog development is a decent bet. However, much of the latest
guidance actually develops MVFR and lower ceilings from northeast
to southwest across the region overnight into Wednesday morning.
Have pretty good confidence in MVFR conditions in the 09Z-15Z time
frame, so will go with prevailing fog in the west and ceilings in
the east.

There should be a pretty thick cu field for much of the afternoon,
but it should most likely be VFR. A stray shower will be possible
mainly over west Kentucky in the afternoon. KOWB would be the
most likely site to be impacted.


&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&

$$

UPDATE...PS
SHORT TERM...SP
LONG TERM...GM
AVIATION...DRS




Area Forecast Discussion

National Weather Service Sacramento CA

 902 PM PDT Tue Apr 18 2017

.SYNOPSIS...
Stormy weather into Thursday, then dry and warmer Friday through
early Monday.

&&

.DISCUSSION...
A few showers are lingering over the Sierra Nevada and Western
Shasta County this evening. Most area should be ending in the next
couple of hours but models are trying to indicate some showers
lingering overnight for Western Shasta County.

Models this evening are in better agreement on the timing of when
the next round of precipitation will occur. Late in the day
precipitation should be spreading along the coastal range. It
should spread over the Northern part of the valley in the evening
hours. Further south it looks like precipitation may start for
Sacramento towards midnight.

.PREVIOUS DISCUSSION...
Long wave trough continues in the EPAC with series of short waves
moving through across CA in moist SW flow aloft. Satellite
imagery showing current wave tracking across Central CA this
afternoon and radar indicating bulk of associated precip is south
of the forecast area. HRRR suggesting potential for some
scattered light evening showers possible over the mountains of
Shasta and Sierra Nevada, otherwise clouds should be decreasing
most areas tonight.

Model spread leading edge of precip with next system across NW
portions of the Interior NorCal by tomorrow afternoon. Mainly
light precip expected across most of the forecast area tomorrow
night as system moves through. Moderate precip possible across
the west slopes of the Sierra Nevada due to orographic
enhancement. Snow levels lower overnight to 5000 to 6000 feet with
some accumulation at pass levels possibly impacting travel.
Showers Thursday morning gives way to mainly dry conditions by
the afternoon as increasing subsidence spreads in from the west.

Dry weather expected Friday into the weekend as large scale upper
ridging from the EPAC progresses over California. Around 10
degrees of warming expected Friday with highs in the upper 70s for
the Central Valley with 50s to lower 70s for the mountains and
foothills.

PCH

$$
.EXTENDED DISCUSSION (Saturday THROUGH Tuesday)


A ridge will be pushing off to the east of us to start the
extended forecast with nice weather continuing on Saturday. A
short wave trough will push in from the west Saturday night and
move over the northern CWA. Overall this should just bring an
increase in clouds to northern parts for the overnight and early
Sunday but maybe an isolated light shower will be possible. Mostly
sunny skies will settle back in by the afternoon Sunday with mild
highs.

Overall quiet weather expected for Monday but a short wave could
bring a few light showers to northern areas after 21z. A bit
stronger wave of energy looks to move over the area on Tuesday but
there is disagreement on the placement of this. For now the best
chances for showers will be in the higher elevations north and
east of SAC. Snow levels look to be quite high with little to no
snow expected.


&&

.AVIATION...


VFR conditions for the next 24 hours. Isolated showers possible
through 9Z. Light winds less than 10 kt. Changing conditions after
22Z from the west will spread rain east late Tuesday and Tuesday
night.


&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$