Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/06/19
Area Forecast Discussion
National Weather Service Gaylord MI
1022 PM EDT Thu Sep 5 2019
.UPDATE...
Issued at 1014 PM EDT Thu Sep 5 2019
Latest surface analysis had weak low pressure centered over the
MN/WI border, with a trailing cold front extending into the
central Plains. The showers/isolated thunderstorms pushing into
the area from the central UP and Lake Michigan are not handled
well at all by most model guidance, although the HRRR has a clue
and the 00Z NAM Nest coming in is also picking up on them. Most of
the precipitation is supposed to come along/ahead of the cold
front (and better dynamics), which is not supposed to arrive
before late tonight/early Friday. Have already updated PoPs to try
and account for latest trends, although additional tweaks are
needed at this time. Also boosted overnight lows a few degrees
given current readings, ample cloud cover, and climbing surface
dew points.
&&
.NEAR TERM...(Through Tonight)
Issued at 300 PM EDT Thu Sep 5 2019
High Impact Weather Potential: Low chance for a few non-severe
thunderstorms late tonight.
Pattern synopsis/forecast: This afternoon`s composite analysis
reveals high pressure continuing to shift east across southern
Ontario into the eastern Great Lakes region through the remainder of
the afternoon into the early evening hours. All the while, upstream
leading compact shortwave continues to slide eastward along a rather
tight thermal gradient across northeastern WI/U.P. before racing
across the region locally later this afternoon and early evening.
Surface low pressure situated across northern MN will slide
southeastward through the remainder of the day before crossing
northern MI overnight into early Friday morning. Combined with
shortwave forcing and interacting with the aforementioned thermal
gradient, expecting an area of stronger QG forcing to work its way
through the region overnight.
Primary forecast concerns/challenges: Shower chances and timing
through the remainder of the day and tonight.
Primarily dry conditions are expected across much of the forecast
area for the remainder of the afternoon (despite increasing cloud
cover). However, fairly persistent eastward movement to radar
returns pushing across far northern Lake Michigan at this time may
pose a chance for light showers/sprinkles, primarily over the Tip of
the Mitt and northwest lower, over the next several hours. More
widespread shower/storm activity to the west of this initial
batch...tied closer to the aforementioned wave and better forcing.
Still expecting to see an expansion of light shower coverage as we
head into later this evening and overnight hours as better forcing
associated with the secondary shortwave trough and surface low slide
across the region. Latest hi-res guidance continues to depict this
thought as well with more numerous showers traversing the region
after 01-03z this evening, continuing off/on right on through Friday
morning. Overall, not a big rain-maker by any stretch with perhaps a
few locations seeing up to a quarter of an inch of rain by the time
precip wraps up Friday morning/midday.
Thunder chances remain awfully low, but I have opted to add in
thunder wording very late tonight across portions of northern lower
as a ever so subtle axis of weak instabilty attempts to fold into
parts of the region from Wisconsin late tonight into early Friday
morning. No severe weather anticipated as that limited threat should
remain to our west over WI.
Tonight`s low temperatures certainly more mild than last
night`s...ranging from the upper 40s in the typically cooler/
interior locales to the low-mid 50s elsewhere.
&&
.SHORT TERM...(Friday through Sunday evening)
Issued at 300 PM EDT Thu Sep 5 2019
...Thunder Friday...
High Impact Weather Potential...Thunderstorms possible early Friday,
but not severe.
Pattern Synopsis/Forecast...Low pressure will be moving into the
forecast area, Friday morning. Thunderstorms along the warm front
will still be continuing into the afternoon, as the low tracks
through the region. CAA begins in E Upper and N Lower, by 21z/Fri,
which should begin to diminish the Thunder threat, but would expect
showers into Friday evening (00z/Sat). Models dry things out, but
850 mb temperatures don`t fall sub +5C until after 12z/Sat and thus
making the delta T >13C. Moisture in the 850-700mb layer is limited
(except on the NAM), so the LE Rain may be spotty to non-existent.
High pressure will then build into the region and dry things out
through Sunday evening.
Primary Forecast Concerns...Main concern is the thunder threat, and
whether we get anything going. Showalter index falls sub 0C so
elevated convection is possible, but it leaves pretty quickly as
the sfc cold air begins to push out the warm, stabilizing the layer.
.LONG TERM...(Sunday night through Thursday)
Issued at 300 PM EDT Thu Sep 5 2019
High Impact Weather Potential...minimal.
Extended (Sunday evening through Thursday)...Sunday night and Monday
will be dry as the next system get set up in the Plains states. High
pressure over James Bay, looks to bring dry air into the region,
long enough to keep the rain out of the area until after
00z/Tuesday. Then the showers will make their way through the lower
peninsula overnight, and then continue into Tuesday, until the cold
front moves through. The cold front should be out by 12z/Wed,
allowing for lingering showers. High pressure builds back into the
region through Thursday, but another low pressure system is set to
move through the region Thursday night into Friday bringing rain
again to the region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 759 PM EDT Thu Sep 5 2019
A weak area of low pressure and associated cold front will cross
lower MI on Friday. Showers and a few thunderstorms are expected
ahead of the cold front, mainly after midnight tonight into midday
Friday. The rain will help CIGs eventually lower to MVFR levels
later tonight, with a few hours of IFR conditions not out of the
question. Generally light winds are anticipated through most of
the period, but will begin to become gusty out of the north and
northwest behind the front late Friday.
&&
.MARINE...
Issued at 300 PM EDT Thu Sep 5 2019
Primarily light winds and waves anticipated through tonight before a
bit of gustiness returns at times during the day Friday...perhaps
reaching SCA wind/wave criteria on much of the Lake Michigan and
Lake Huron nearshore waters. A bit of gustiness possible Saturday as
well, perhaps reaching SCA criteria before lighter winds/waves
return to wrap up the weekend.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...PB
NEAR TERM...MG
SHORT TERM...JL
LONG TERM...JL
AVIATION...PB
MARINE...MG
Area Forecast Discussion
National Weather Service Cheyenne WY
848 PM MDT Thu Sep 5 2019
.UPDATE...
Issued at 843 PM MDT Thu Sep 5 2019
Widely scattered thunderstorms, a few strong, have been developing
along several outflow mergers over far southeast WY, with weaker
convection over much of Carbon County this evening. Latest RAP
advects over 1000 j/kg CAPE westward toward Cheyenne. Increased
PoPs to 30 percent over Laramie County through late this evening.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 239 PM MDT Thu Sep 5 2019
Latest radar loop was showing a few showers and thunderstorms
developing over the Sierra Madre and Snowy Ranges. There is also
some showers developing over the northern Laramie Range. This
activity is not expected to become severe this evening due to
limited instability. Latest water vapor loop was showing a fairly
distinct shortwave approaching the west coast. This feature is
drawing up quite a bit of moisture ahead of it. This shortwave and
moisture is expected to spread east during the next 24hours and
perhaps bring some low clouds to parts of the area along and east
of the Laramie Range tomorrow morning. Meanwhile, tomorrow
afternoon we should see more coverage of showers and
thunderstorms. Severe coverage will be somewhat limited with the
best focus across Converse and Niobrara counties where the shear
will be close to 30 to 35kts near the surface low. Most of this
convection should weaken and it shifts east during the evening.
.LONG TERM...(Saturday through Wednesday)
Issued at 230 AM MDT Thu Sep 5 2019
A fairly dry forecast for Saturday as upper shortwave moves
through and shifts winds westerly through much of the day. Need to
watching the next front that will be to our north over southern
Montana Saturday night into Sunday. Much colder air behind this
front as it surges south. GFS showing 700mb temperatures behind
that front of +4 to +5C as it surges south and southwestward
Sunday morning.
GFS continues to show a negatively tilted upper low tracking
across Wyoming Sunday afternoon into Monday. Looking at fairly
widespread rainfall and maybe another chance at severe
thunderstorms. Also need to be watching for strong wind event as
700mb winds near 50kts. Would think these would mainly impact the
Arlington wind prone area...but will need to watch. Craig to
Casper 850/700mb height gradients exceeding 65 meters for a time
Sunday night into Monday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 545 PM MDT Thu Sep 5 2019
VFR under mostly cloudy skies west of KCYS, mostly clear to the
east. Showers and isolated thunderstorms over southeast Wyoming
TAF sites through 06/06Z. Variable and erratic gusts up to 40 kts
associated with convective activity. Generally calm and dry
overnight under a high-based BKN to OVC cloud deck. Winds and
chances of showers and thunderstorms increase across the region
after 06/18Z. Winds will be out of the south and west with gusts
to 25 kts ahead of an incoming frontal passage expected to clear
the area by 07/06Z.
&&
.FIRE WEATHER...
Issued at 239 PM MDT Thu Sep 5 2019
Marginal fire weather conditions are in place this afternoon. The
only location reporting critical fire weather conditions is Otto
Road along the I-80 foothills. Otherwise, wind speeds are fairly
light with RH`s around 20 to 25 percent. Moisture will be on the
increase this weekend which will favor more suppression on the
current fires at Pedro Mountain and Ashenfelder. The main concern
for the next few days will be new starts from lightning. Drier
and very windy conditions are expected on Monday after the passage
of a strong frontal boundary. Then southwest flow will kick in on
Tuesday over areas west of the Laramie Range which will favor
more critical fire weather conditions.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
UPDATE...MAJ
SHORT TERM...REC
LONG TERM...GCC
AVIATION...AB
FIRE WEATHER...REC
Area Forecast Discussion
National Weather Service Green Bay WI
1039 PM CDT Thu Sep 5 2019
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Friday
Issued at 228 PM CDT Thu Sep 5 2019
The latest RAP analysis and satellite/radar imagery show shortwave
energy and an associated low pressure system moving into the
northern Minnesota early this afternoon. Within the warm advection
regime ahead of the low, strong storms are moving across northwest
WI within the leading edge of steep mid-level lapse rates and
elevated instability. These storms should push across north-
central WI during the mid to late afternoon and northeast WI
early this evening. As the low pressure moves across the area
tonight, potential for strong storms and precip trends are the
main forecast concerns.
Tonight...Low pressure remains expected to track across far
northern WI. Ahead of the low, mid-level moisture advection will
push across the region during the evening. Meso-models have been
under-doing convection all morning on the edge of the elevated
instability over northeast Minnesota and northwest WI. Since
models point towards upstream conditions pushing east across
northern WI this evening, think will see scattered storms impact
the area. With most unstable capes of 750-1000 j/kg, effective
shears of 25 to 30 kts, and mid-level lapse rates of 6.5 to 7.5
C/km, could see a few strong and isolated severe storms through
the evening hours with hail being the primary threat. Any storms
should taper off to light rain overnight as precip gradually ends
from southwest to northeast. Cloud bases will lower overnight as
northwest winds increase behind the low. As a result, temps
shouldn`t fall very much, so went with lows in the 50s at most
locations.
Friday...Ample low clouds are expected to linger across the area
during the morning above a breezy north wind. Some clearing is
possible during the afternoon, but forecast soundings indicate
that fair weather clouds will develop where sunshine occurs.
Therefore think skies will remain partly sunny/partly cloudy until
the end of the afternoon. Lowered temps a couple degrees due to
the greater cloud cover expected. Highs mostly ranging from the
mid 60s to low 70s.
.LONG TERM...Friday Night Through Thursday
Issued at 228 PM CDT Thu Sep 5 2019
Minimal changes were made to the long term forecast. The main
opportunity for precipitation is still expected early next week,
with a few lighter showers possible at other times. Temperatures
remain on the cooler side of normal.
For Friday night, added some patchy fog to the forecast, mainly
across central and northern Wisconsin, as guidance continues to
hint at this possibility. This also seems reasonable given a
period of clear skies and lingering moisture from tonight`s rain.
This weekend, surface high pressure will be situated from
southern Manitoba to southern Ontario. Meanwhile, a surface low
will move across the Central Plains. This puts northeast
Wisconsin between two opposing air masses. Models continue to
show the drier air to the north winning out, but that doesn`t
eliminate the potential for some short-lived showers or sprinkles.
The best chance would be Sunday morning and afternoon south of
Hwy 29, closer to the surface low. The GFS is the most aggressive
with this scenario, while the EC and Canadian keep the precip
further south. Clouds will likely be variable through the weekend
as they spread in from any showers or storms further west.
Next week, models continue to pinpoint late Monday into Tuesday as
the next chance for more widespread rain or thunderstorms. The
Canadian has slowed down on timing, coming more in line with the
GFS and EC. This leads to increased confidence in precip Monday
night and Tuesday. Conditions dry out Wednesday as high pressure
builds into Wisconsin, then beyond Wednesday forecast confidence
is low as models diverge.
Temperatures will generally be below normal through the long term,
possibly rising closer to normal through the midweek depending on
cloud cover and precip. Used a blend of the best performing
guidance for daily highs and lows.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1035 PM CDT Thu Sep 5 2019
Ceilings were gradually lowering across the area, but the IFR/LIFR
ceilings were still to the northwest. Those should drop southeast
later in the night as a cyclone migrates across the region. Only
a slow improvement is anticipated Friday as cyclonic flow and
plenty of low-level moisture linger across the area.
&&
.MARINE...
Issued at 228 PM CDT Thu Sep 5 2019
North winds behind a low pressure system will become
gusty on Friday morning. Winds of 15-25 kts are expected to peak
around early afternoon before subsiding by early evening. A small
craft advisory may be needed from mid-morning through mid-
afternoon Friday.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......KLJ
AVIATION.......Skowronski
MARINE.........MPC
Please see the previous forecast discussion below for more details
on the upcoming cooling trend. Keene
&&
.AVIATION...For the 06/00Z TAFs...Isolated to scattered
thunderstorms will continue from the coastal range eastward through
this evening, some of which will be strong producing gusty and
erratic winds and hail. Thunderstorms are likely to peak in coverage
and intensity through 02Z this evening but activity is likely to
linger until around midnight/07Z. VFR ceilings are expected to be
the predominant condition into this evening, except for MVFR
ceilings and visibility in thunderstorms.
Meanwhile, coastal IFR/LIFR stratus/fog will persist through Friday
with the most extensive coverage and lowest ceiling heights early
Friday morning. -DW
&&
.MARINE...Updated 800 PM PDT Thursday 5 September 2019...Winds and
seas will remain relatively light through Tuesday night. Weak high
pressure will build into the waters Friday into Saturday. A series
of weak to moderately strong fronts will follow late Saturday
through Tuesday with a chance of light rain, The strongest of these
fronts will move onshore Monday. Moderate west swell will build
Sunday into Tuesday, rising from around 4 feet to a peak around 7
feet. -DW
&&
.FIRE WEATHER...Updated 905 PM PDT Thursday 5 September 2019...On
Friday, expect dry but continued warm weather over the area. An
upper trough will approach from the west and move into the area
this weekend, bringing cooler conditions and a chance for showers,
especially at the coast and into the Umpqua, Southern Oregon
Cascades and northern Klamath County. Strongest afternoon breezes
on Friday will be east of the Cascades. There is a slight chance
for thunderstorms late Saturday afternoon and evening over the
Southern Oregon Cascades, mainly from Crater Lake northward. Also
on Saturday, expect some breezy to gusty afternoon and evening
winds for areas east of the Cascades and into the Shasta valley.
Another upper trough is possible early next week, bringing continued
mild weather and additional chances for showers. -CC/Keene
&&
.PREV DISCUSSION... /Issued 546 PM PDT Thu Sep 5 2019/
DISCUSSION...Thunderstorms will be main concern through early
this evening. Plenty of low level moisture exist from overnight
thunderstorms with several locations west of the Cascades showing
dewpoint temperatures in the upper 50s to 60 degrees. This is
pretty impressive for this time of the year and for this area. The
fact that thunderstorms gave off some latent heat is going to
provide a spring load for a very active day. In other words once
that spring gives way, thunderstorms will begin to fire up.
Were already starting to see the first signs of that. The latest
satellite image shows instability clouds already developing with
storms developing north of Crater Lake and east of the Cascades.
Additionally the radar is starting to light up with thunderstorms
developing in Modoc, Lake and eastern Klamath County.
Thunderstorm coverage will increase over time with scattered to
numerous thunderstorms expected for most of the area. The only
exception will be in northwest Douglas County and most of Siskiyou
County where storms are expected to be isolated.
Frequency of lighting and storm intensity is also expected to
increase. Plenty of dynamics remain ahead of the upper low during
and the models suggest the upper low/trough could become negatively
tilted late this afternoon during the time of max heating.
Upper level winds will also be stronger today, so it`s not out of
the question a few storms could be strong to perhaps severe with
locally gusty winds and small hail. Keep in mind that gusty and
erratic winds are possible near the core of thunderstorms.
Of note: There`s good agreement among the convective allowing models
(CAM) for thunderstorms to fire up early to mid afternoon, then
increasing in coverage late this afternoon into this evening. of
particular concern is west of the Cascades where the CAM shows what
could be strong storms forming along the Jackson/Josephine County
border and moving north towards Douglas County. Additionally the
latest high res HRRR also shows this with storms developing between
3-4 pm pdt.
The focus for thunderstorms are expected to shift north and east as
the upper trough swings through the area tonight. Still could not
rule out thunderstorms in northern Lake and Klamath County later
tonight, but the bulk of the action will ne north and east of our
area.
Dry weather returns Friday with shortwave ridging building into the
area.
The operational ECMWF and GFS and ensembles remain in fairly good
agreement suggesting a pattern change for the weekend and likely
lasting into at least the middle of next week. General troughiness
will set up over the area bringing cooler weather. There is the
potential for showers each day, but the specifics on location,
timing and frequency varies.
An upper trough approaches from the west to northwest Saturday
afternoon, then splitting with an upper low forming south of our
forecast area Sunday. The pattern is not one typically favorable for
thunderstorms Saturday, but some of the models do hint at marginal
instability from around Crater Lake north, so we`ll add a slight
chance of storms there.
Overall were expecting isolated to scattered showers. Saturday, the
best chance for showers are expected to be along and east of the
Cascades. Weak shortwave ridging builds in Sunday, but the models
hint at some precipitation along the coast and north of the Umpqua
Divide. Suspect this may be overdone given the shortwave ridging, so
we`ll keep a slight chance mention for now.
Another upper trough arrives Sunday night with troughing remaining
over the area Monday through Wednesday. At the surface will be a
series of weak fronts bringing a slight chance to a chance of
showers mainly north of the Umpqua Divide, coast and northern
Cascades. It will remain cool with temperatures near seasonal norms.
-Petrucelli
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning until 11 PM PDT this evening for
ORZ616-617-620>625.
CA...Red Flag Warning until 11 PM PDT this evening for
CAZ280-281-284-285.
Pacific Coastal Waters...None.
$$
Area Forecast Discussion
National Weather Service Marquette MI
630 PM EDT Thu Sep 5 2019
.SHORT TERM...(This evening through Friday)
Issued at 410 PM EDT THU SEP 5 2019
Water vapor imagery and RAP analysis show wnw flow into the Upper
Great Lakes this aftn. Well-defined shortwave that was over sw
Saskatchewan 24hrs ago has weakened on its track toward Lake
Superior. Trailing shortwave moving into northern ND/nw MN will
become the more dominate feature tonight as it amplifies into the
Great Lakes region. Shra/tsra, some strong/svr tsra, that were over
northern MN early this morning have been tracking ese, mostly to the
s of Upper MI today. As a result, the only measurable rainfall to
occur has been from far western Upper MI toward KIMT. However,
recently, approaching left exit of upper jet supporting the upstream
shortwave and increasing deep layer forcing are resulting in new
shra development across ne MN into western Upper MI. The increase in
forcing for upward motion is quite apparent in the last hr or two of
vis satellite imagery which shows a notable increasing trend in
convective cloud development beyond that associated with current
shra.
As shortwave amplifies se into Great Lakes region tonight, expect
the upstream shra to continue developing/expanding in coverage while
spreading across the fcst area. Increasing upper divergence within
the left exit of the upper jet will be a major contributor to the
expanding shra. Given the forcing, some of the higher qpf model
solutions may be on the right track. So, there could be some local
0.5 to 1 inch rainfall amounts tonight, but in general, 0.25 to 0.5
inches should be the rule. With axis of elevated instability aloft
(potentially several hundred j/kg) also translating at least as far
e as central Upper MI, will likely see a few tsra as well tonight.
Sfc low pres over nw MN will track ese across far northern WI and/or
western thru s central Upper MI tonight/early Fri. With the rainfall
occurring over Lake Superior and as winds swing around to a ne to n
direction with passage of the low, will likely see considerable
upslope stratus/some high elevation fog develop later tonight. These
low clouds may then go on to plague the w and n well into Fri aftn.
Upsloping may also result in some -shra/-dz lingering for much of
the morning. If the low clouds hang on thru Fri across the w and n,
temps may not get above 60F. For now, have fcst high temps in the
60s across the board, coolest w and n and warmest s central.
.LONG TERM...(Friday night through Thursday)
Issued at 435 PM EDT THU SEP 5 2019
Models indicate that a gradually progressive pattern will prevail. A
mid/upper level ridge from the Southern Plains through the Rockies
will give way to lowering heights into early next week as a strong
shortwave moves in from the Pacific this weekend. As a result,
Northwest flow through the Great Lakes with mainly below normal
temperatures will give way to southwest flow next week bringing a
warm front a more widespread precipitation toward the region.
Friday night, a strong shortwave moving through nrn Ontario just
north of Lake Superior will drag a weak trough/front through
the northern Great Lakes. Although the stronger forcing will remain
well to the north, some light rain showers or sprinkles may be
possible with the front, mainly through the north.
Sat-Sun, Some lake enhanced rain may be possible early Saturday with
favorable sfc-750 mb moisture and cyclonic low level flow.
A secondary cold front is expected to move through the area late
Saturday dropping 850 mb temps into the 2C to 4C range. With lake
temps in the 13C-15C range, instability will be marginal to support
any lake effect with increasingly anticyclonic flow. Surface high
pressure will continue to dominate through Sunday with seasonably
cool air as winds slowly veer to the northeast. Enough low level
moisture will linger to keep skies mostly cloudy through the period.
Mon-Tue, A warm front approaching the area by late Monday into
Tuesday should bring widespread rain into the region. There is more
uncertainty with the details regarding sfc low pressure development
and pcpn timing/intensity as the GFS/GEFS/GEM suggest that a
stronger shrtwv and sfc low will move through to the west of Upper
Michigan compared to the ECMWF. Some thunder may also be possibly by
Tuesday as moisture/instability spread to the northeast. PWAT values
climbing at or above will also support the potential for heavy rain.
Wed-Thu, Models consensus would push the higher pcpn chances east of
the area by Wed. Cooler air with ne to e flow is expected to
dominate the region as sfc high pressure builds southward from
northern Manitoba and northern Ontario.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 630 PM EDT THU SEP 5 2019
VFR conditions will prevail into the evening at all sites. The shra
along with development of upsloping winds at the terminals will
likely result in conditions falling thru MVFR to LIFR. Gradual
improvement is anticipated late Fri morning/early aftn.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 410 PM EDT THU SEP 5 2019
Low pres tracking from nw MN across far northern WI/southern Upper
MI tonight/early Fri will result in increasing easterly winds
backing northerly tonight/early Fri across Lake Superior. There may
be a period of 25-30kt wind gusts across western Lake Superior
tonight as the low passes by the area. Winds will then fall back blo
20kt across the lake on Fri. Passage of a cold front will then bring
increasing NW winds late Fri night/Sat. Expect the strongest winds
over the e half of the lake where gusts may reach 25-30kt on Sat.
Winds will diminish for Sun, but with sfc high pres passing by just
n of Lake Superior, E to NE winds up to 20kt will be possible over
far western Lake Superior. Winds will likely be on the increase
later Mon into Tue as the high pres departs and low pres tracks e
toward the Upper Mississippi Valley. Not out of the question that
there could be a period of easterly gales as the low approaches.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...JLB
AVIATION...07
MARINE...Rolfson
Area Forecast Discussion
National Weather Service Spokane WA
450 PM PDT Thu Sep 5 2019
.SYNOPSIS...
A weather system will bring an increasing threat of showers and
thunderstorms to the region this evening into Friday. Warmer and
drier weather is expected Saturday. Then expect a major pattern
change as cool and unsettled weather will arrive on Sunday and
is expected to linger through most of next week.
&&
.DISCUSSION...
Tonight through Friday: A series of disturbances will move across
the area this afternoon through Friday. The first is moving in
now bringing an increase in clouds. Radar is picking up on some
returns across the eastern Columbia Basin into the Palouse, LC
Valley and Camas Prairie. Think this is mainly moistening the
atmosphere for later, but we could see some sprinkles or very
light rain out of it. The next round will move in after sunset.
This stuff is currently down in southern and central Oregon and it
producing thunderstorms. The elevated instability isn`t super
impressive, but do have slight chance mentioned overnight for
portions of central WA into the ID Panhandle. Rain and isolated
thunderstorms will continue through the day on Friday.
The best threat of thunder looks to remain south of our forecast
area, but do have a slight chance mentioned extending from Moses
Lake east into the Idaho Panhandle...mainly south of I-90 tonight
and Friday.
Several changes made to the forecast for the next 24 hrs. First
was added some wind gusts overnight down in the Blue Mountains
towards the LC Valley, Palouse and Camas Prairie as this is the
best area for thunderstorms. The HRRR has shown a weak gust front
the last several runs. Second change was to increase overnight
lows given the extensive cloud cover expected. Third was decreased
our high temps for Friday given the cloud cover and rain,
especially for the eastern third of WA and the entire north ID
Panhandle. /Nisbet
Friday night and Saturday...High pressure will rapidly build
in from the west Friday evening. Up-sloping flow into the Idaho
Panhandle mountains will keep a chance of showers and possible
thunderstorms in the forecast through the evening. This will be
followed by a quick warming and drying trend through the day on
Saturday. This will be short lived, however, as another storm
system will be right behind. Expect on warn and dry day with
temperatures rebounding 5-10 degrees over Friday.
Saturday night through Wednesday...We are looking at a major
pattern change through this period. A fast moving storm system
will move into the region Saturday night and break down the weak
ridge. A secondary low will follow on Sunday night. This low will
then get reinforced by multiple short wave disturbances moving
through the trough through about Wednesday. This will open the
door for several days of cool, wet, and unsettled weather.
Temperatures are expected to be 2-3 degrees on the cool side of
normal with highs in the upper 60s to upper 70s. We can expect
widespread showers and thunderstorms each day Sunday through
Tuesday. The showers will get pushed back into the northern
mountains on Wednesday. Moisture is plentiful and this will result
in a widespread wetting rain, with moderate rain in the
mountains.
Thursday...Once more high pressure will build into the region on
Thursday. Again this will be short lived as another storm system
looks to move into the region on Friday. This will result in one
warm and dry day, before the chances for showers and thunderstorms
increases again on Friday. Tobin
&&
.AVIATION...
00Z TAFS: Challenging forecast through the period as moisture
moves up from the south overnight into Friday. All sites should
remain VFR under light northerly winds through the bulk of the
overnight hours. Currently mid level moisture will be exiting the
region early this evening with mere sprinkles. Waiting for the
next band of convection overnight with light showers and embedded
isolated thunderstorms. Some local gusts winds are possible
especially near KPUW and KLWS. By early morning, the showers
become more stratiform with the potential of MVFR conditions,
especially at KGEG, KSFF, KCOE and KPUW. Anticipate improving
conditions from west to east through the afternoon. /rfox.
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 61 72 54 81 56 73 / 80 90 10 0 20 40
Coeur d`Alene 61 67 52 79 55 71 / 80 90 10 0 20 50
Pullman 60 70 51 81 51 69 / 70 80 10 0 30 50
Lewiston 68 77 61 87 62 75 / 70 60 20 0 40 50
Colville 57 77 46 85 48 80 / 40 50 0 10 30 50
Sandpoint 57 66 50 80 53 72 / 60 80 10 0 20 60
Kellogg 60 64 56 78 58 69 / 70 100 30 0 20 60
Moses Lake 64 82 56 86 58 80 / 40 30 0 10 40 30
Wenatchee 69 84 63 84 64 79 / 20 30 0 10 30 20
Omak 63 83 58 86 60 79 / 30 20 0 10 30 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$