Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/05/17
Area Forecast Discussion
National Weather Service State College PA
1004 PM EDT Sat Nov 4 2017
.SYNOPSIS...
A warm front will lift northward through the region Sunday
followed by a strong cold front on Monday. After a wet day on
Monday, a ridge of high pressure will build across the region
for the middle of next week with colder temperatures. A much
stronger cold front will move in by next Friday, as a large
high pressure system from the northern plains with abnormally
cold air builds eastward on Friday.
&&
.NEAR TERM /UNTIL 8 AM SUNDAY MORNING/...
The area of rain has blossomed as expected as it moved into the
sern cos. Still, many locations have picked up only one or two
tenths of an inch of rainfall. A few spots around the Harrisburg
metro are closer to a third of an inch. It is tapering off there
as forcing/weak LLjet moves off to the east. Bright band on
radar around 9kft makes it look worse/heavier than it really is.
It is that time of year when the melting layer starts to rear
it`s head. Have called the precip for much of the rest of the
night drizzle as the vertical extent of moisture is not that
deep - generally less than 5kft. Also, the veering low level
wind profile should make a broad area of upglide into the
central mtns. Temps should move little with lots of clouds and
mainly southerly flow.
Prev...
Rain sliding through on time, but overall, it is very light and
few restrictions are being seen at local airports. The rain will
slow down a bit and redevelop over the SE half of the area as
SWrly flow increases in the cloud layer.
Prev Prev...
The nose of the surface high that extends from southern New
England down into the Mid Atlantic states is retreating off to
the east, paving the way for increasing moisture snaking in
from the southwest. The nearest rain is over the panhandle of WV
making slow but steady progress northward. This will likely be
the rain we experience over southern and central PA over the
next 8-12 hours, before more rain associated with the warm
advection associated with advancing warm front enters from the
NW.
The HRRR takes the bulk of rain through my southern zones
through late evening before bringing new showers into the NW
around or shortly after midnight. It all points to a fairly high
POP but low QPF forecast overnight.
Overnight lows in the 40s will actually be quite mild for early
November, averaging a couple of degrees either side of 10 deg
warmer than normal.
&&
.SHORT TERM /8 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
The best chance of rain Sunday will be over about the northern
half of the region Sunday as the warm front tries to erode the
cool air damming wedge in place over the Central Mountains.
As the warm air aloft begins to mix down, we will likely see
some breaks develop in the clouds across the Laurel Highlands.
Elsewhere, cold air damming will hold in the low ceilings, but
spotty light rain and drizzle is likely to abate by afternoon,
when model soundings show layer of moisture becoming quite
shallow.
Model blended guidance supports high temps Sunday between
60-65F over most of the forecast area, about 5-10 deg above
normal.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
Models been showing a cold front moving in Monday, bringing
another round of showers to the area Sunday Night and Monday.
I did slow down the back edge of the showers on Monday. Left
mention of thunder in. SPC day 2 has a large area of higher
storm potential for Sunday just to the west of our area. Not
seeing a deep low or height falls, but PW values come up some,
and LLJ in place. Another factor is EML, given southwest flow of
abnormally warm air across the southern plains. Thus support
for thunder. I did up QPF to the northwest, to fit better with
the models and other offices.
Fast moving waves at 50 mb could bring a shower toward southern
PA, later Tuesday.
A strong cold front moves in by Friday, may be very little QPF.
Main thing will be a brief window for lake effect, but the main
response may be more off Ontario than Erie.
Did not bring lows next Saturday Night up as much as the
superblend, given how strong the high is.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
0040Z Radar has light reflectivity`s moving into central PA
with MVFR cigs at AOO. Light rain has started at the southern
TAF sites. Have adjusted timing of the onset of the restrictions
and as the strong flow aloft has stalled have either dropped
LLWS from the southeast TAFs. As the warm front enters in
overnight into tomorrow, the moisture will continue to stream
through into the region. Expecting cigs and vsbys to
progressively get worse. IFR is possible at the central and
western TAF sites around 06Z and around LNS by 13Z. Drizzle and
IFR cigs remain persistent through Sunday morning with just
gradual improvement over the south and southwest by midday into
the afternoon. Northern half will likely hang on to restrictions
all day.
Outlook...
Mon...Widespread MVFR/IFR with a cold front. Thunderstorms are
possible as well.
Tue...Mainly VFR.
Wed-Thu...No sig wx.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte/Martin
NEAR TERM...Dangelo/La Corte
SHORT TERM...La Corte
LONG TERM...Martin
AVIATION...Ceru
Area Forecast Discussion
National Weather Service Hastings NE
653 PM CDT Sat Nov 4 2017
.SHORT TERM...(This evening through Sunday)
Issued at 241 PM CDT Sat Nov 4 2017
Plenty of mid level cloud cover continues to stream across the
region this afternoon as most of the low level stratus from this
morning has eroded. This has allowed for a few sun breaks in
spots...along with allowing temperatures to climb into the lower
50s the past hour or so. As a result...did tweak afternoon temps
upward a bit as originally this forecaster was a bit too
pessimistic with low cloud cover for today.
For tonight...there is a bit of uncertainty with the forecast as
with lots of mid level cloud cover across the area this
afternoon...have a difficult time seeing a rapid fall off in
temperatures overnight ahead of an approaching cold front...which
if realized...could potentially allow some fog to form. Despite
this low potential...short term models such as the HRRR are
indicating there could be the development of widespread dense fog
across the local area during the late night through overnight
hours ahead of the approaching front. Because of this...thought it
was prudent to at least add patchy fog to the forecast generally
south of highway 6...with a rapid erosion of any fog that does
develop as the aforementioned cold front tracks south across the
local area. In addition...while there is only a week signal in
model data...do think there is a potential for at least some
sprinkles across our north with forcing from the front...so also
added this low end probability to the forecast.
What is more certain is that a mostly cloudy and blustery day is
anticipated across the local area Sunday. With lots of low level
stratus around and strong cold air advection...should see
afternoon temps struggle to climb out of the mid 40s...with most
locations seeing readings 10 or more degrees below this afternoons
highs. In addition...gusty northerly winds will filter in behind
the front...making for a relatively unpleasant day across the
region tomorrow.
.LONG TERM...(Sunday night through Saturday)
Issued at 241 PM CDT Sat Nov 4 2017
Generally below normal temperatures along with a few small chances
for precipitation are expected through the extended periods.
Tuesday appears to be the coldest day of the extended periods
behind another cold front...when temperatures are not forecast to
climb out of the 30s and a weak disturbance could bring some light
snow showers to the local area. That said...the better moisture at
this time appears to be focused to our west...and only light
snowfall amounts...from a dusting to less than an inch...are
anticipated across the local area from the late Monday night
through late Tuesday night period.
Cool air will then linger across the local area for several
days...with a potential warming to near seasonal norms late in
the period as a transitory ridge is forecast to slide across the
plains late in the week...with another chance for some light
precipitation possible next weekend.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday)
Issued at 649 PM CDT Sat Nov 4 2017
Main issue will be a cold front moving in tonight. Just before the
cold front passes through, we could see some lowering visibility,
but confidence is not high if this will happen, and if it does,
how low, and how long would be another big question. It appears
that lower visibility may be more likely to the south of the
terminals. Introduction of MVFR ceilings are expected with the
arrival of the cold front. Wind will be a bit gusty with the cold
front passage as well overnight.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Rossi
LONG TERM...Rossi
AVIATION...Heinlein
Area Forecast Discussion
National Weather Service Green Bay WI
858 PM CDT Sat Nov 4 2017
Updated aviation portion for 06Z TAF issuance
and new information added to update section
.UPDATE...
Issued at 845 PM CDT Sat Nov 4 2017
Drizzle will probably diminish overnight as low-level flow veers
overnight. But light rain/showers closer to the cold front
advancing into the area from the west will likely shift into
north-central Wisconsin later tonight. But the main concern is
fog formation. Visibilities have been slowly edging down but are
still generally AOA 1 1/2 miles across the forecast area. Areas
where snow is still on the ground are certainly at risk of having
some dense fog, but lower visibilities over southeast Wisconsin
could expand north into east-central Wisconsin as well. Plan to
handle with an SPS for now, but am ready to post a dense fog
advisory if there is a significant downturn in visibilities.
&&
.SHORT TERM...Tonight and Sunday
Issued at 233 PM CDT Sat Nov 4 2017
The latest RAP analysis and satellite/radar imagery show a cold
front over the northern Plains and high pressure positioned over
the east coast. Light showers continue over northeast Wisconsin
early this afternoon associated with a weak shortwave moving
across the region. These showers should exit later this afternoon.
But broad low level warm advection may also lead to drizzle
redeveloping. As the front moves towards Wisconsin late tonight,
light precip trends and fog potential are the main forecast
concerns.
Tonight...Low level warm advection will continue across the
region, ahead of a cold front that will move across western
Wisconsin after midnight. Moisture will remain trapped beneath an
inversion, with saturation extending upward into the 850-700mb
layer during the evening. Though progged soundings indicate that
the top of the saturated layer will lower some this evening, the
depth should remain sufficient for widespread overcast conditions
with periods of drizzle. Temps should not move very much, so not
expecting any freezing drizzle. However, with some snow cover over
north-central and far northeast WI and a moist boundary layer,
could see dense fog develop late tonight. As the front moves
closer to north-central WI late, decent forcing in the left front
quad of a jet streak could bring more widespread shower activity.
Nearly steady temps tonight in the mid 30s to low 40s.
Sunday...The front will continue to move east across north-central
and northeast WI. Showers will likely impact north-central WI for
this first half of the morning before they lift northeast into the
Upper Peninsula. The showers are expected to become more widely
scattered as the front moves into eastern WI around midday. With
the passage of the front and shifting of the winds to the
northwest, should see any fog lift shortly thereafter. Highs
ranging from the upper 30s to upper 40s.
.LONG TERM...Sunday Night Through Saturday
Issued at 233 PM CDT Sat Nov 4 2017
Sunday night and into much of the work week will consist of mainly
dry conditions with temperatures below normal levels. Colder air
may provide some periods of minor lake effect snows far north.
Weak northwest flow or near zonal flow will keep primary weather
systems well south and north of the area for at least the first
half of the work week. A couple of cold fronts will keep temps
chilly along with brief periods of snow shower activity across the
far north as winds turn northwest behind the cold fronts. Progs
are attempting to focus the first period of lake effect snow
showers Sunday night after the Sunday cold front. Another cold
front with weak short wave slides over Monday afternoon and
evening followed with northwest winds late Monday night into
Tuesday.
Progs begin to divert for the later half of the week. GFS lifts a
warm front north over the state Thursday night into friday while
the ECMWF drops another cold front over the state near the same
time period. Both solutions provide an overall drier regime
through at least Friday, but the forecast temperatures and pcpn
type after Thursday remain in the low confidence level.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 845 PM CDT Sat Nov 4 2017
The main aviation forecast issue continues to be visibilities and
ceilings overnight. Weak WAA will continue to feed moisture into
the region the rest of the evening, but flow will eventually veer
southwest with will result in a loss of the low-level lift. Plan
to stick close to a consensus of the guidance products which have
done pretty well thus far this evening. Expect the IFR/LIFR/VLIFR
conditions to persist until mid-morning Sunday, then conditions
should improve.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE.........Skowronski
SHORT TERM.....MPC
LONG TERM......TDH
AVIATION.......Skowronski
Area Forecast Discussion...UPDATED
National Weather Service San Joaquin Valley - Hanford CA
809 PM PDT Sat Nov 4 2017
.SYNOPSIS...
Weakening cold front will move through the area overnight. Light
precipitation is expected into Sunday morning. Clearing and drier
conditions are expected through next week. A cold front is
expected to approach the region on Thursday night bringing
another chance of precipitation. Gradual clearing next weekend.
&&
.DISCUSSION...
Regional radar and satellite imagery shows a few isolated light
showers as the front slides south across CENCAL overnight. HRRR
and new NAM12 guidance is dry across most of the area with
clouds and a few isolated showers in the Sierra overnight into
Sunday morning. We have cancelled the Winter Storm Warning and
lowered POPS and QPF. Temps are looking good at this time and we
are not seeing any issues with the wind forecast.
&&
.PREV DISCUSSION... /issued 403 PM PDT Sat Nov 4 2017/
DISCUSSION...
A weakening frontal system continues to slide slowly south,
nearing northern portions of our area. Just a few light sprinkles
have been detected so far across the central California interior
today. Precipitation along the frontal zone has been decreasing
over time as the front gradually weakens. Short-range hi-res
models illustrate this trend, maintaining mainly light
precipitation across the area, though still at least some
locally moderate snowfall accumulations in the higher elevations
around the Yosemite vicinity. With travel impacts still possible
in this area, the winter weather highlight for there continues.
Models continue to generally wash out the front as it moves through
the region tonight. Just some light upslope showers lingering in
the south end through Sunday evening in continued cyclonic flow.
Dry and warming conditions are then progged into Wednesday under
shortwave ridging with temperatures climbing to around climo.
Models are coming in better agreement with the next low pressure
system approaching from the Northeast Pacific Thursday. Models
have not been consistent with the timing and intensity of this
system, but it looks like another chance for showers spreading
south across the area Thursday with a few showers lingering into
Friday. At this time, confidence in precipitation amounts is low,
but snow levels look like they will be above 8000 feet. Timing and
precipitation amounts with this system will be further refined
with additional model runs.
&&
.AVIATION...
Areas of MVFR can be expected in the foothills and higher elevations
of the Sierra during the next 24 hours with local IFR and mountain
obscurations in precipitation. VFR conditions will prevail elsewhere
across the central California interior through 12z Sunday.
&&
.AIR QUALITY ISSUES...
None.
&&
.CERTAINTY...
The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is high.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.php for additional information
an/or to provide feedback.
&&
.HNX Watches/Warnings/Advisories...
NONE.
&&
$$
public...JDB
avn/fw...MV
prev discussion...JEB
synopsis...JDB
weather.gov/hanford
Area Forecast Discussion
National Weather Service Marquette MI
743 PM EDT Sat Nov 4 2017
.SHORT TERM...(This evening through Sunday)
Issued at 329 PM EDT SAT NOV 4 2017
Water vapor imagery and RAP analysis show a trof over sw Canada into
the nw CONUS with a rather vigorous looking shortwave over southern
Saskatchewan. Downstream, wsw flow extends toward the Upper Great
Lakes. Shortwave that aided snowfall last night/early this morning
is tracking across Lower MI. Pcpn associated with that feature has
departed, leaving behind low clouds and some spotty -dz/-ra across
the fcst area.
During the short term, attention turns to the shortwave currently
over southern Saskatchewan. This wave will track ene, reaching
northern Ontario on Sun with associated cold front crossing the fcst
area during the morning thru mid aftn. Persistent waa/isentropic
ascent ahead of the shortwave should maintain some spotty -ra/-dz
tonight. Where se winds veering s are upsloping across central Upper
MI, fog may become locally dense. Deepening moisture profile and
some increase of deep layer forcing should support a modest increase
in -ra coverage from w to e late tonight/Sun morning along/ahead of
the cold front as it sweeps across the area. As was the case
yesterday, it appears roughly the nw half of the fcst area will see
best coverage of -ra under more favorable positioning of the upper
jet. Pcpn will quickly end with fropa, though there is some question
as to whether there will be enough lingering low-level moisture
within post-frontal upslope wnw flow to produce some light pcpn over
the w. With a steady drop in sfc dwpts behind front this aftn over
the western Dakotas and points w per sfc obs along with rather
vigorous caa to weaken/lift inversion, don`t think there will be any
upslope pcpn across the w as some model guidance indicates. By 00z,
850mb temps will be down to -8 to -10C over western Lake Superior,
providing a lake-850mb delta-T of at least 15C. While this would be
sufficient to begin LES, inverted-V temp/dwpt profile in the
boundary layer by that time along with shallow cloud depth per fcst
soundings suggests LES is unlikely to develop before 00z Mon. Temps
tonight will remain steady or perhaps rise a degree or two. Temps
over the e should reach the mid 40s on Sun prior to fropa while
temps over the w will fall from morning highs in the mid/upper 30s.
.LONG TERM...(Sunday night through Saturday)
Issued at 315 PM EDT SAT NOV 4 2017
Overall, there will be chances for lake effect snow showers,
primarily in the west wind snow belts, and cooler than normal
temperatures through the first half of the week. Towards the
middle/end of next week, the upper-level pattern becomes more
active across the region as flow becomes more progressive across
the CONUS.
Monday and Tuesday: Primarily zonal flow across the Upper Great
Lakes will keep us predominately in west-northwesterly flow. This
will promote below normal temperatures with lake effect snow chances
beginning early Monday and lingering through Tuesday in the west and
northwest wind snow belts.
Tuesday night through early parts of next weekend: Tuesday night
into Wednesday, 850mb temperatures will warm in response to a
shortwave digging south across the Upper Great Lakes. This should
allow lingering lake effect snow to diminish; however, a trailing
cold front associated with a low pressure system progged to track
towards/across the Hudson Bay area will drop south across the area
Wednesday into Thursday. There is quite a bit of uncertainty across
the medium-range models in regards to the strength the system, and
thus the colder air behind this system and overall track of post-
frontal high pressure. Therefore, confidence in how precipitation
chances will unfold, along with temperatures, late Wednesday through
Thursday are low. The ECMWF is much stronger with this system, thus
allowing for a stronger post-frontal surface high and the potential
for some of the coldest temperatures of the season. Whereas, the GFS
continues to revert back towards its warmer, less amplified solution
advertised a few days ago, which would keep our temperatures more
seasonal. The Canadian is similar to the GFS; therefore, tending to
lean towards the GFS/Canadian solutions at this time.
Friday through Saturday, all of the medium-range models are
advertising another shortwave trough tracking across the Upper Great
Lakes. However, they diverge fairly significantly in regards to the
strength of the upper-level energy, and thus the timing and track of
its associated surface low. Given the highly amplified pattern
suggested by the ECMWF, it is much slower with the arrival of this
system. The GFS essentially splits the difference between the faster
Canadian and slow ECMWF solutions. Even though there is considerable
uncertainty, it does look like at least some locations across Upper
Michigan should see additional precipitation chances to round out
the week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 734 PM EDT SAT NOV 4 2017
Conditions in low stratus will remain at airfield landing
minimums at KSAW through much of tonight. IFR conditions will
mostly prevail at KIWD and KCMX thru tonight. Some -ra/-dz is
expected at times with an increasing chance of rain at the western
TAF sites overnight. Passage of a cold front Sun morning will
result in improving conditions to MVFR at all terminals. The post-
frontal westerly winds will become gusty to at least 25kt at
KCMX. &&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 329 PM EDT SAT NOV 4 2017
Ahead of an approaching cold front, expect se to s winds of
generally 20-30kt across Lake Superior tonight. There may be a few
gale force gusts to 35kt over eastern Lake Superior this evening.
Cold front will sweep across the area late tonight/Sun. In its wake,
expect w to nw winds up to 30kt across much of Lake Superior with a
few hrs of gale force gusts possible late aftn/evening across the e
half of the lake. Mon/Tue, winds will be mostly in the 15-25kt
range, though there will be a period of lighter winds for part of
Tue. Winds will increase back to mostly 20-30kt Tue night thru Thu.
Could be a period of gales for portions of Wed/Thu ahead of and in
the wake of a cold front that passes.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...Ritzman
AVIATION...Voss
MARINE...Rolfson
Area Forecast Discussion
National Weather Service San Francisco Bay Area
657 PM PDT Sat Nov 4 2017
.SYNOPSIS...A few lingering showers this afternoon as a weak
surface cold front passes through the Bay Area. Next front moves
into the North Bay Sunday evening with another chance of light
rain. The front will fall apart as it reaches the Golden Gate and
any rain chances end by sunrise Monday. Dry Monday and Tuesday.
Increasing clouds Wednesday with a chance of rain by Wednesday
night and Thursday as a stronger front arrives. Long range trends
continue to look unsettled, especially from Interstate 80
northward.
&&
.DISCUSSION...as of 01:46 PM PDT Saturday...The cold front that
moved into the Bay Area last night continues to move slowly
southward as it begins to fall apart/wash out. Despite its
weakening, lingering showers continue to impact parts of the East
and South Bay. Farther north skies are actually clearing with some
sunshine over the North Bay. Based on latest trends and most
recent run of the HRRR will keep a few lingering showers before
completely drying out with clearing overnight. Given the clearing
skies up north temperatures will dip into the 30s in some
locations by Sunday morning.
Much drier conditions are expected on Sunday and trended forecast
in the that direction. However, models have been advertising
another weak front Sunday afternoon and Sunday night entering the
North Bay. There are definitely differences with the GFS and EC
remaining drying, but the NAM still holds on to some chances.
Therefore, will keep the best chance for the North Bay and only a
slight chance south to Santa Cruz.
Dry weather returns by Monday afternoon through Tuesday. The break
will be short lived as medium range models have been indicating
an active pattern midweek with wet weather returning to the Bay
Area. 12Z models bring rain back to the North Bay early Wednesday
then spreading it southward through the day. Additional rain is
expected again on Thursday and possibly into Friday. A lot of fine
tuning will be done between now and then, but initial rainfall
totals look decent with 0.5-1" for the North Bay and lesser
amounts southward for the Wednesday system.
&&
.AVIATION...As of 6:57 PM PDT Saturday...Drier air has arrived in
most spots per 24 hour check on dewpoint temps, however residual
moisture in the lower levels of the atmosphere is causing BKN-OVC
cigs at 2,500-7,000 feet from the South and East Bay areas to the
north Central Coast. The 850 mb to 300 mb layer relative humidity
will steadily decrease area-wide, reaching 20-30% overnight thus
improving outgoing radiative cooling. A patch or two of valley fog
is possible by morning, including KSTS IFR is forecast Sunday
morning.
925 mb cold air advection will be ongoing with an additional 1C-5C
cooling into early Sunday morning before turning neutral during the
day Sunday thus a marine inversion is not forecast to return in
the near term. However, without the marine inversion it`s still
possible cigs temporarily trend toward patchy IFR over the coastal
waters and along the immediate coast at times late tonight. The 850
mb 0C isotherm is forecast to reach the Monterey Bay area Sunday,
expect a lowering freezing level to near 5,000 feet then modifying
temperatures arrive late Sunday into Monday.
Vicinity of KSFO...W-NW winds near 15 knots til 04z this evening becoming
light W later this evening. Tempo BKN cig 12z-16z Sunday otherwise VFR
tonight and Sunday.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...MVFR/VFR cigs tonight, tempo IFR cigs and
visibilities are possible by midnight into early Sunday morning.
00z tafs indicate BKN MVFR cigs Sunday with a possibility they trend
back to VFR Sunday morning. Boundary layer RH increases again over the
Monterey Bay Sunday afternoon and evening. For 06z taf issuance may
decide to forecast BKN-OVC cloud coverage through Sunday. 850 mb 0C
isotherm arrives Sunday morning thus lowering freezing levels prior
to some modification in temps late Sunday into Monday.
&&
.MARINE...as of 4:42 PM PDT Saturday...A cold front slowly moving to
the south will continue to dissipate through the evening. Behind it,
seas will gradually subside through Sunday. A second weak cold front
will arrive late on Sunday into Monday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...None.
$$
PUBLIC FORECAST: MM
AVIATION: Canepa
MARINE: Bell
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Area Forecast Discussion
National Weather Service Nashville TN
711 PM CDT Sat Nov 4 2017
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
Went ahead and did an early update to the forecast this evening as
some showers are continuing across Hickman, Williamson, and Maury
Counties. This activity appears to be forming ahead of a very weak
shortwave aloft approaching the Tennessee River per water vapor
imagery and latest model data. HRRR suggests this activity will
continue for another couple of hours before falling apart, with
the rest of the night dry although some patchy fog is anticipated,
which could be locally dense in some areas. Added a slight chance
pop to all zones through 03Z to account for current showers, and
started patchy fog earlier in the evening as dewpoint depressions
are already low in western counties. Also tweaked low temperatures
for tonight but nothing significant. An unusually warm and windy
day for early November is on tap for tomorrow with likely record
breaking warmth so get out and enjoy it!
&&
.AVIATION...
00Z TAF DISCUSSION.
A couple showers developed at TAF issuance time about 30 miles SW
of BNA. These should weaken but could approach BNA very briefly
around 0130Z. Otherwise, mostly BKN clouds will gradually become
more widespread and lower tonight. MVFR ceilings will become
common between 06Z and 09Z...and continue through most of Sunday.
Patchy fog also possible at all TAF sites for several hours
leading up to sunrise Sunday. Expect light south winds to continue
overnight and then increase and become a tad gusty by around 15Z
Sunday. Winds will stay up the rest of the day on Sunday as
surface pressure gradient tightens in advance of the slow-moving
MS/OH Valley cold front. That front should not move into Middle
TN until beyond the current TAF cycle... probably Sunday night or
Monday.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......Shamburger
AVIATION........49
Area Forecast Discussion
National Weather Service Phoenix AZ
339 PM MST Sat Nov 4 2017
.SYNOPSIS...
The region will remain situated between strong high pressure
centered over Mexico and strong low pressure centered near the
Pacific Northwest. A series of weak upper disturbances will move
across the region during the workweek bringing periods of
cloudiness. There will also be a slight chance of showers over
higher terrain areas of Arizona on Tuesday. Seasonal high
temperatures can be expected the first half next week with a
little bit of warming during the latter half of the week.
&&
.DISCUSSION...
A band of isolated weak showers that tracked across Maricopa
County earlier today has shifted into Gila County early this
afternoon but has largely dissipated. Cloud cover has also
decreased but a deck of scattered to broken mid cloud persists
over much of south-central AZ including metro Phoenix. The slow
dissipation of cloudiness may be aided by the approach of the
southern end of a system that is mainly tracking far to the
north. RAP also indicates a more subtle impulse ahead of that
which could be a factor as well.
Expect less cloudiness on Sunday but with some subtle cool
advection, max temps will not be any warmer than today. On Monday
and Tuesday, a weak upper low (currently off the southern
California coast within a split in the Westerlies) will weaken
and move eastward in response to a much more potent system moving
through the far northeast Pacific. Meanwhile, a short wave trough
evolving out of the northern Rockies and Great Basin will also
acquire a stronger positive tilt, with a glancing influence across
the Four Corners and Southwest potentially resulting in a few
showers Tuesday (primarily over northern and eastern portions of
Arizona). All in all, precipitation chances look quite low
throughout the forecast period for our CWA, but increased
cloudiness is a good bet on Monday and Tuesday.
In the extended period, the large-scale pattern will remain quite
progressive, with transient shortwave ridging building across the
Southwest into late next week and bringing a minor warming trend.
However, the heat will have a hard time building as another
upstream system approaches the Western CONUS into next weekend.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
A lingering batch of shallow mid clouds (bases AOA FL100) will
linger through the afternoon before slowly dissipating. Surface
winds will maintain a westerly component through the afternoon
before trending to typical nocturnal patterns after 06Z. Winds
aloft (through most of the troposphere) will remain westerly.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mostly clear skies will continue the rest of the day and overnight
with only some very minor high clouds. Southwest and west surface
winds will be favored the rest of the day and evening with some
minor gustiness possible (more noticeable over the Imperial Valley
this evening).
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday:
Moist westerly flow aloft combined with a weak weather
disturbance is expected to keep humidities somewhat elevated
across the districts during the Monday-Wednesday period, with even
a slight chance for wetting rains over the higher terrain north
and east of Phoenix during the late Monday-Wednesday period.
Somewhat drier conditions and mainly clear skies to return on
Thursday and Friday as weak high pressure moves eastward across
the region. Minimum humidities it the 20-35 percent range Monday-
Wednesday to fall into the 15-30 percent range on Thursday and
Friday, with good overnight recoveries. Near-normal temperatures
on Monday and Tuesday to become slightly above normal during the
Wednesday-Friday period.
&&
.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
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DISCUSSION...AJ/Rogers
AVIATION...AJ
FIRE WEATHER...Percha