Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/12/19
Area Forecast Discussion
National Weather Service Boston/Norton MA
1020 PM EDT Sat May 11 2019
.SYNOPSIS...
High pressure centered over the eastern Great Lakes will lift
northeast into Canada tonight with the ridge axis over New
England. A wave of low pressure will move from the central
Appalachians out to sea to our south late tonight and Sunday,
giving us a touch of light rain, especially Sunday morning.
A stronger low pressure system passes south of New England
early next week, bringing rain, wind, and unusually cold
temperatures later Monday into Tuesday. The weather improves
some by mid to late next week, but temperatures likely remain
below normal with on and off rain.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
1030 am update...
Not much change to the forecast this evening. Nudged timing of
precip arrival a bit, toward the HRRR as it`s had a good handle of
the placement of the precip shield currently over Long Island.
Previous discussion follows.
Quiet, clear, calm. But top-down moistening overnight as rain
moves in towards morning as a wave of low pressure encroaches
out of the Appalachia. 1020 high N/E, isallobaric, pressure-
gradient flow providing undercutting of drier air within the
low levels as isentropic over-running of warm-moist air proceeds
beneath a favorable location of the right-rear-quadrant of the
H3 upper-level jet. Following HRRR trends, put the timing of
rain after midnight over SW New England with any and all out-
comes spreading N/E overnight being light. Increasing clouds
will put a cap on falling temperatures. Looking at lows in the
40s. Increasing PoPs towards morning, with high-chance to likely
over the lower CT River Valley by daybreak.
Last note ... wind shift noted along E-MA coast at this hour
should capitulate winds eastward for a brief period of time
before going back NE with the isallobaric response as the low
over the Appalachians progresses E with some strengthening as
high pressure shifts N/E over SE Canada.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Sunday...
Northeast to east flow will mean a cloudy and cool day. Have
lowered high temperatures to only 50 to 55 across the region.
As low pressure passes to the south of New England, some light
rain is likely, mainly from the Mass Pike southward, and mainly
during the morning. Rainfall amounts are expected to be less
than 0.25 inches. In the afternoon, all models indicate that
high pressure to our northeast attempts to strengthen and nudge
some drier are in at low levels, from northeast to southwest.
Any light rain should be driven southeastward and off the coast
by mid-afternoon.
Sunday night...
Southern New England will be in between weather systems...the
low having passed to our southeast and a new storm that will be
forming to our south. So, we are expecting a cloudy but mainly
dry night. Cannot rule out a few showers, mainly in CT, RI, and
southeast MA late. Overnight lows again will be in the lower to
mid 40s. East-northeast winds will gust to around 20 mph along
the south coast of RI and MA.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
*/ Highlights ...
- Widespread rain, possible high terrain wet snows Monday - Tuesday
- Concurrently, blustery E-onshore winds, possible coastal concerns
- Cool, dry Wednesday, Friday, Sunday
- Shower chances Thursday, Saturday, and early next week
*/ Overview ...
Cooler than average conditions and wet-weather chances. Resurgence
of N-Atlantic ridging, initially W Europe that re-emerges S of Green-
land. Briefly slowing the upstream pattern coincident with sweeping
Pacific energy. An opportunity for storm development Tuesday, a Mid-
Atlantic Nor`Easter up the NE CONUS. Gradual progression E through
the week, nudged by bowling energy across the NE Pacific, +PNA ridge
pushed E. Will see NE CONUS H5 troughing edge into SE Canada putting
New England within the fringe of warmer interior CONUS westerlies
and colder N Canadian flow. Exchanging frontal boundaries with the
area of stronger storm development shifting towards Newfoundland.
*/ Details ...
Monday into Tuesday ...
Evolving storm system bringing widespread rain with potential high
terrain wet snows. Mentioned in the OVERVIEW, brief, slowed pattern
progression, Pacific energy manifests into a stout, stacked closed
low across the NE CONUS. Initial over-running setup Monday evolves
into comma-head low into Tuesday. Storm track extending through the
column critical as to wind fields and frontogenetical banding, the
subsequent trowaling along the backside where column cooling and
cold can manifest dynamically downward, wetbulbing in the process
beneath the occlusion of the H5 low. Have medium confidence with
this system as there remains considerable spread in small features.
A lot of winter-thinking going on here with the track of the H85-7
low along with subsequent banding features, trowaling moisture, and
deformation.
Given synoptic-proximity of features, good model forecast agreement
of a over-running widespread rain beneath diffluent motions Monday,
however the heaviest remaining offshore with the anticyclonic warm-
moist conveyor belt convergent nose. Stronger punch Monday night -
Tuesday with the low stacking, cyclonically trowaling moisture into
the occlusion, converging within the low-mid levels especially along
the high terrain. Moderate to possibly heavy rain and should enough
cold air manifest downward especially overnight there could be some
mountain wet snows. Can`t rule out rainfall amounts within the 24-hr
period exceeding +1". Likely PoPs. Minor snowfall accumulations in
where a coating is possible, have hinted 1" atop the Berkshires.
If synoptic-dynamic forces come together yielding deep omega values
to 40 microbars per second, precipitation pounds, rain or snow. Note
11.12z GFS exhibiting some interesting banding signatures extending
back to the Berkshires Monday night lingering into Tuesday within
better snow growth regions, however the NAM is largely absent. Again
all track dependent, especially so with the wrapping dry-slot. Good
model forecast agreement of low thicknesses more so at H85-7. Either
a cold rain and/or wet snow, preference towards cooler than average
conditions. As mentioned earlier, possibly some record `lowest-high-
temperature` will be broken.
Final note, blustery E-onshore winds, a fetch that begins Sunday and
continues through Tuesday night. Two concerns: 1.) Coastal hazards.
Boston tides around 10.3 feet. Can handle a 2 foot surge if it comes
down to that. Waves building. Can`t rule out possible beach erosion
especially across E/NE MA, Cape Ann especially. 2.) Strong, possibly
damaging winds. Higher confidence high terrain. 11.12z GFS stout in
comparison to the EC. Will play a role in aforementioned swell and
possible E MA coastline threats and impacts.
Wednesday ...
Drying out though beneath cyclonic flow rearward of the exiting H5
low, scattered to broken low cloud decks with steep surface to H85
lapse rates courtesy lingering cold pool aloft (H5 to around -20C).
Chance showers for the high terrain, breezy NW winds. Chilly day
with warmest weather S/W.
Thursday ...
Chance showers widespread. Additional energy downsheared with an
accompanying cold lobe, H5 temperatures approaching -24C. Whether we
exceeding on 2m temperatures, depending on the timing of attendant
Pacific wave and continental-moisture, if moisture can be lofted
high enough through the column, can`t rule out some graupel. Low
confidence forecast.
Friday onward ...
Reinforcing cooler than average conditions with an initial shot of
wet-weather followed by a wedge of Canadian cold. As the H5 trof
slowly moves out, energy continually bowling through presses S
surface cold frontal features maintaining NW flow and cooler than
average conditions aloft. A lull potentially for the latter half of
the weekend with a Hudson Bay 1040 high pressing S, preceding a
strong storm lifting out of the Central Plains for early next week.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Sunday Night/...High confidence.
0z update ...
Tonight ...
VFR. Increasing mid-high level CIGs, lowering and thickening towards
low-end VFR by morning. N/NE wind, around 10 kts along the coast with
gusts around 15 kts. Chance -RA towards morning especially S/W. No
VSBY concerns.
Sunday ...
Continued lowering CIGs, lowest around 16z. Widespread low-end VFR
with MVFR over the lower CT River Valley (i.e., CEF / BDL / HFD /
IJD and points S/W). Likely -RA S of MA pike. No VSBY concerns aside
from 6SM BR, worst S/W. -RA pushing S and CIGs lifting after 16z
towards evening. E wind 5 to 15 kts, strongest S/SE coast with gusts
around 20 kts.
Sunday night ...
VFR. CIGs continuing to lift, hovering around 6-8 kft agl. Only
chance -RA lingers along the coast. No VSBY concerns. E winds continue
around 5 to 10 kts, strongest along the coast with gusts up around
20 kts.
KBOS Terminal...
Notable wind shift E of the terminal out by Hull as of 23z. Expecting
winds to shift due E the next hour or two and then waver back NE
during the evening hours before veering back E. This capitulation
of the winds outlined in the TAF.
KBDL Terminal...High confidence in TAF.
Outlook /Monday through Thursday/...
Monday: Mainly VFR, with local MVFR possible. Windy with gusts
up to 30 kt. Chance RA.
Monday Night: MVFR/IFR conditions possible. Windy with gusts up
to 30 kt. RA.
Tuesday: Mainly VFR, with areas IFR possible. Windy with local
gusts up to 30 kt. Chance RA.
Tuesday Night: Mainly VFR, with local IFR possible. Breezy.
Chance RA, chance SHRA.
Wednesday: Mainly VFR, with areas MVFR possible. Breezy. Slight
chance SHRA.
Wednesday Night: Mainly VFR, with local MVFR possible. Slight
chance SHRA.
Thursday: VFR. Chance SHRA.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Sunday Night/... High confidence.
7 pm update ...
Overnight...
E/NE winds with a weak pressure gradient that`ll keep both winds
and seas below small craft advisory thresholds.
Sunday...
A wave of low pressure passes S of the waters. NE to E winds will
increase to around 10 to 15 kt over the S waters, gusts up to
20 kts. Small Craft Advisory for seas building to 5 ft in the SW
outer waters S of Block Island, where winds could also gust to
25 kt late in the day. Likely rain.
Sunday night...
Expanded the Small Craft Advisory E to include waters S of Marthas
Vineyard and Nantucket for seas building to 5 to 7 ft and E to NE
winds gusting to 25 kt. Chance rain, mainly over the S waters.
Outlook /Monday through Thursday/...
Monday: Low risk for gale force winds with gusts up to 30 kt.
Areas of rough seas. Chance of rain.
Monday Night: Low risk for gale force winds with gusts up to
30 kt. Rough seas up to 12 ft. Rain.
Tuesday: Low risk for Small Craft Advisory winds with gusts up
to 30 kt. Rough seas up to 15 ft. Chance of rain.
Tuesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Rough seas up to 13 ft. Chance of rain,
chance of rain showers.
Wednesday: Winds less than 25 kt. Areas of rough seas. Slight
chance of rain showers.
Wednesday Night: Winds less than 25 kt. Local rough seas.
Slight chance of rain showers.
Thursday: Winds less than 25 kt. Areas of seas approaching
5 ft. Chance of rain showers.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 11 PM Sunday to 6 AM EDT Monday for
ANZ255.
Small Craft Advisory from 8 AM Sunday to 6 AM EDT Monday for
ANZ256.
&&
$$
SYNOPSIS...Sipprell/GAF
NEAR TERM...Sipprell/BW/GAF
SHORT TERM...GAF
LONG TERM...Sipprell
AVIATION...Sipprell/GAF
MARINE...Sipprell/GAF
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
1047 PM EDT Sat May 11 2019
.SYNOPSIS...
High pressure arriving from the west tonight will bring a dry
but chilly night before low pressure south of the region spreads
clouds and potentially a few showers into southern NH early
Sunday. Drier conditions work back in for later Sunday through
the first half of Monday before a strengthening coastal low
pressure system ushers in another period of cool and wet
conditions...with the potential for accumulating snow in the
mountains Monday night. Precipitation from this system will
taper off by late Tuesday with gradually moderating temperatures
and continued chances for showers.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Update...Minor changes to reflect latest observational trends.
Keeping an eye on showers to the SW. Model guidance keeps this
mainly to our S...but radar trends suggest that things are
currently a little farther N than modeled. I made a slight
expansion Nwd with PoP...but overall a minor change. Could see
the need for some likely PoP with the next update across Srn NH
if trends continue.
Previous discussion...
High Impact Weather Potential: Potential for frost for some
active growing season areas away from southern NH.
Pattern: Weak shortwave ridging is building into the region as of
this writing with a region of surface high pressure over the eastern
Great Lakes arriving from the west. This has brought dry and
seasonably cool conditions to the area today. This surface high
pressure system will largely dominate our weather through
tonight while backing mid level flow over the Mid Atlantic
region ahead of a shortwave dropping southeast from the northern
Plains will coax a warm front & associated moisture south of
the region to start moving back in our direction.
Through this evening: Drying airmass has resulted in a slowly
eroding cloud deck in the mountains...with downsloping assisting
with the clearing to the south. As we lose daytime heating and
head into the evening expect most locations to become mostly
clear with winds gradually subsiding as the boundary layer
stabilizes and the llevel gradient weakens. Temperatures won/t
fall all that far through 8pm...mid 40s north...and lower/mid
50s south.
Tonight: Seasonably dry airmass overhead tonight with PWATs near -1
sigma over northern areas with values ranging from 0.25" near the
international border to around 0.75" over southern NH. Col
region sets up over southeastern New England...with shortwave
ridging arriving from the west...but with trough quickly
arriving to it/s south and west. Thus the squeeze play will be
on between dry air to the north and advancing deep moisture
plume from the south. In terms of any precipitation...it appears
that the high pressure to our north will largely win out.
Precipitation probabilities from the SREF and HREF suggest
maintaining low chance to slight chance PoPs (20-40%) over
southwest New Hampshire.
The other concern is the potential for frost as the active growing
season has now begun for much of the area outside the mountains.
From Concord south...no worries as deeper cloud cover will keep
temperatures from falling much below 40. To the north of the H7
moisture shield simulated satellite imagery from the HRRR shows
an advancing region of high clouds after midnight...concurrent
with agreed upon uptick in H5-3 moisture. The overall setup is
very marginal for frost in the very northern portion of our
active growing zones. Therefore...and in collaboration with
Caribou and Burlington...will hold off on any headlines and
include an hour or two of patchy frost mention in these areas.
Certainly a chilly night with 30s likely for most spots outside
of southern NH.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
High Impact Weather Potential: Minimal.
Pattern: Aforementioned shortwave over the Mid Mississippi Valley
Sunday morning will lift north and east to a position near Detroit,
Michigan by daybreak Monday. Primary low pressure center will
quickly occlude and be centered very near the mid level low by
daybreak Monday. East of this low...there are two features of note.
The first is some semblance of a weak wave of low pressure that
rides east off the Mid Atlantic coast on Sunday. Another...triple
point low will take shape over Virginia Sunday evening...pushing off
the Mid Atlantic coast by Monday morning. At the same time as these
features are making a run at our region...high pressure will be
firmly locked in to our north and east. Thus...our focus will be on
precipitation chances as these low pressure areas gradually near our
region under southwesterly flow aloft.
Sunday: Area of warm advection-induced rain showers will likely make
their closest approach Sunday morning associated with eastward
moving wave along surface warm front to our south. As this feature
moves east of our longitude...there is a bit of a push of dry llevel
air from the north that should bring dry conditions through the
afternoon. Thus...will continue the low PoPs over southern areas
through the morning...but keep conditions dry for much of the day.
It will likely remain cloudy under a mid deck over southern NH which
will hold temperatures down...but it should turn out mostly sunny
elsewhere. T8s around +1-2C should allow areas outside of southern
NH to reach around or a bit above 60...with upper 50s to the south.
Sunday Night: Southwesterly flow aloft will begin to win out as we
move into Sunday night with surface occlusion lifting into the
eastern Great Lakes and triple point low off the Mid Atlantic coast.
Still...given the position of the primary and secondary lows...
forcing for precipitation will remain rather meager. Expect
increasing clouds under top-down saturation with some potential for
a shower or two over the southern half of the area but nothing
substantial from a QPF perspective. Temperatures will not be
warm...but with the added cloud cover they should be a few degrees
warmer than the night previous and currently don/t see any frost
concerns.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Slow moving upper trough will set the stage for damp and cooler
weather for much of the week...
Monday not looking too bad as closed upper low over the eastern
Great Lakes heads east. Surface reflection of this system will
move southeast out of western PA and off the coast south of New
England by late in the day. Will see increasing clouds through
the day and will likely include some low chance pops for the
Connecticut Valley in the afternoon. High temperatures will be
fairly uniform across the area with most locations reaching the
lower to mid 50s.
Low pressure off the Jersey coast Monday evening will slowly
drift northward overnight reaching the eastern end of Long
Island by Tuesday morning. Expect rain to push in from the
southwest Monday night generally affecting southern and central
zones. Lows overnight will range from the mid 30s north to near
40 south.
Low pressure will remain nearly stationary off the southeast
New England coast Tuesday. Expect steadier rain in the morning
to give way to more showery type precipitation and areas of
drizzle in the afternoon. High temperatures will top out well
below normal with most of the region only reaching the mid to
upper 40s.
Surface low pressure will become trapped under upper low off
Cape Cod Tuesday night and will only show modest movement to
the east overnight. Moist low level flow off the maritimes will
keep low clouds....scattered showers and patchy drizzle in the
forecast for overnight. Temperatures will show little change
overnight with most areas dipping into the mid 30s to near 40.
Upper low will continue to spin off the coast on Wednesday as
dreary and cold weather continues in New England. Can`t rule out
a stray shower but most of the forecast area should see a dry
day. Highs will range from the upper 40s north to the upper 50s
south.
Low pressure will continue to pull off to the north and east
Wednesday night and Thursday. Will see some partial clearing
in western zones overnight but most of western Maine will
remain cloudy. Lows will range from the mid 30s to lower 40s.
Clouds will persist in western Maine on Thursday with partly
sunny skies to the west. High temperatures will finally get
back to near normal ranging from the mid 50s north to the mid
60s south.
Looking for variable clouds Thursday night as weak high
pressure builds in from the west. Lows will range from the mid
30s north to the mid 40s south. Friday looking fair with
seasonable temps.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Short Term...
Summary: High pressure will build north of the region through
tonight with a stalled frontal boundary remaining well south of the
area. This front and associated low pressure will start to advance
towards the region Sunday night.
Restrictions: VFR conditions are expected to dominate all sites
through Sunday night. There is some low potential for a shower to
reach MHT-CON-PSM Sunday morning, but no restrictions are expected.
Winds: Northwest winds 14g22kts through this evening drop to less
than 10kts overnight before shifting easterly 5-10kts for the day on
Sunday. Winds will become calm/light-variable Sunday night.
LLWS: No LLWS Expected through Sunday Night
Long Term...
VFR Monday. MVFR/IFR ceilings developing in southern zones
Monday night. Widespread IFR/LIFR ceilings Tuesday through
Wednesday. VFR with areas of MVFR ceilings on Thursday.
&&
.MARINE...
Short Term...
Winds and waves are expected to remain below small craft levels
through Sunday night as high pressure builds into the region
tonight and remains to the north of the area through Sunday
night.
Long Term...
SCA`s likely Monday night through Tuesday night.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
NEAR TERM...Legro
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
725 PM CDT Sat May 11 2019
.Updated for 00Z Aviation Discussion...
Issued at 712 PM CDT Sat May 11 2019
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 348 PM CDT Sat May 11 2019
Water vapor imagery along with RAP h5 heights shows a potent mid
level low spinning over central SoDak. However, models continue to
track this feature farther and farther west, with it now forecast to
drop from central SoDak to northern MO in the next 24 hours. As a
result, precip shield associated with this waves PVA will slide
southwest of the MN River in southwest MN through tonight.
Southerly flow ahead of this wave is resulting in some theta-e
advection and the development of a rather agitated cu-field on
satellite. We are seeing scattered returns on radar, but the day
cloud phase RGB is showing this convection is not deep enough to
lead to ice formation at the cloud tops. In addition, these showers
are moving into an airmass that had around a 30 degree F dewpoint
depression, so not much of this activity is reaching the ground,
since they are moving fast enough that once they moisten that atmo
enough to allow precip to reach the ground, they`ve moved off to the
north. As a result, didn`t change what we had going much with a
broad area of 20 and 30 PoPs working across all but western MN.
Greatest threat for precip will be in eastern MN/western WI, where
the RAP has been showing best moisture getting up into the h7-h6
layer.
Tonight, we should actually see skies clear out outside of southwest
MN as diurnally driven activity dissipates. This clearing will be a
theme that will carry us into Sunday as well, with a mainly sunny
and pleasant day expected across eastern MN and western WI. A ribbon
of deeper moisture will remain from northeast MN into eastern SoDak,
where cloud cover is expected to be thicker and the threat for an
isolated afternoon shower will exist. However, with a surface ridge
bisecting the MPX area on Sunday, we`ll have anti-cyclonic low level
flow, which should further aid in us having a rather pleasant Sunday.
.LONG TERM...(Monday through Saturday)
Issued at 348 PM CDT Sat May 11 2019
Showers and thunderstorms look possible Tuesday afternoon & evening
as a shortwave drags a weak cold front across the area. With the
better forcing remaining north of the international border I
wouldn`t expect too much in the way of coverage across
central/southern Minnesota into west-central Wisconsin, so will
continue to mention lower-end PoPs of 20-40%.
Ridging builds into the central United states midweek, which will
allow for temperatures to warm back towards normal values for mid-
May, with highs returning to the 70s and overnight lows around 50.
Broad but weak high pressure will influence the Upper Midwest so
expect mainly dry conditions during this time, but a few weak
impulses riding the northwesterly flow on the periphery of this
ridge could lead to some minor precipitation chances Thursday.
The forecast becomes more interesting Friday into the weekend, as an
amplified pacific jet noses in to the central US. Models this
morning have trended towards a warmer and more active pattern
setting up across the Upper Midwest with strong meridional flow aloft
developing by the weekend. This more amplified solution would allow
for warm and humid Gulf air to surge into the region, allowing for
our first taste of summertime temperatures and possibly even strong
to severe thunderstorms. A less amplified solution would keep the
warm and humid air off to our south, with a return to cool, cloudy
and rainy conditions north a warm front. Will stick close to the
ensemble/guidance mean for temperatures and precipitation chances
for now since it is still plenty early, but these may need to be
increased significantly if this more amplified trend continues.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 712 PM CDT Sat May 11 2019
Generally VFR conditions with a few showers this evening, then
expect the showers to dissipate, but could see some MVFR clouds,
especially in western Minnesota at KAXN and KRWF. Meanwhile
ceilings will be higher to the east. Winds will generally be out
of the south southeast.
KMSP...
VFR conditions with south east winds. Could see some broken clouds
develop around 5000 to 6000 feet on Sunday.
/OUTLOOK FOR KMSP/
Mon...VFR. Wind S 5-10 kts.
Tue...VFR. Chc -TSRA. Wind SW 5-10 kts bcmg NW 10G20 kts.
Wed...VFR. Wind NW 5 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&
$$
SHORT TERM...MPG
LONG TERM...ETA
AVIATION...JRB
Area Forecast Discussion
National Weather Service Reno NV
302 PM PDT Sat May 11 2019
.SYNOPSIS...
High pressure will provide abundant sunshine, warm temperatures,
and relatively light winds through the weekend. A stray shower or
thunderstorm in the Sierra and north of Susanville and Gerlach is
possible on Sunday, with chances retreating to well south of
Highway 50 by Monday. A breezy and cooler pattern is expected mid
to late next week with a chance for showers.
&&
.SHORT TERM...
Drying and warming has ensued today as high pressure begins to
press south from Oregon and Idaho, with generally clear skies,
relatively light north to east winds, and valley temperatures in
the 60s and 70s. With the dry air and clear skies tonight, a solid
diurnal swing of 35-40 degrees between today`s highs and tonight`s
lows will be common.
The upper ridge will press south from Oregon/Idaho into Nevada
and California on Sunday, bringing warm, dry, and mostly sunny
conditions to most of northeast CA, the Sierra, and western
Nevada. However, a few spots in the Sierra and north of Gerlach
and Susanville could see some cumulus buildups by mid to late
afternoon Sunday, with the GFS and NAM still showing hints for
very isolated showers and perhaps a brief thunderstorm or two.
The HRRR and SREF thunderstorm progs are not impressive and even
the GFS/NAM instability is rather anemic, so it could easily wind
up just being some high-based cumulus buildups with virga or
brief light rain. Still, with light convergent surface winds in
the afternoon near the Sierra, it is hard to rule out a few
convective cells by late afternoon and early evening so low POP
was continued in the Sierra and into far western and northwestern
NV.
On Monday, the upper ridge axis slides eastward and a drier
southwest flow aloft filters in across the region with a return of
westerly afternoon zephyr breezes. This should shutdown chances
for showers on Monday for areas roughly north of Highway 50, while
the Mono-Mineral area may maintain enough instability and mid-
level moisture to develop some cumulus buildups with a few showers
or storms during the afternoon.
The flow turns more southwesterly on Tuesday ahead of an approaching
trough, which brings a drier and more stable air mass to the region.
We have removed all mention of showers in Mono-Mineral Counties
with the latest runs showing any deeper instability pushing off
into central and eastern Nevada. Winds will likely increase some
over Monday as a trough of low pressure approaches the Pacific
Northwest coast and increases the thermal gradient across the
region. -Snyder/Fuentes/Dawn
.LONG TERM...Wednesday through Saturday...
No significant changes were made to the forecast this cycle. Gusty
afternoon winds will persist through the end of the week ahead of
an incoming trough Friday into Saturday. Wednesday will be dry but
widespread chances for showers return Thursday.
Thursday and Friday will be the days with the best chances for
showers, but they will be hit-or-miss in nature. Thunderstorms
are not expected at this time. Temperatures will be cooler behind
the trough, dropping to around 5 degrees below normal. Snow levels
will also drop to around 7,000`, but only the highest elevations
should see any accumulations. We are still several days out, so
impacts are still TBD. Ensembles (i.e. GEFS and EPS) are in good
agreement and suggest we`ll stay in a troughy, cooler pattern
through the beginning of next week. Cassie
&&
.AVIATION...
VFR conditions and generally light winds will prevail for the next
few days. There will be a slight chance of showers and thunderstorms
for the Sierra and areas north of Gerlach and Susanville on Sunday.
Any storms that develop could produce erratic, gusty winds and
brief heavy rain. Gusty winds and precipitation chances will
return later in the week. Cassie
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno
Area Forecast Discussion
National Weather Service Tallahassee FL
1041 PM EDT Sat May 11 2019
.NEAR TERM [Through Tonight]...
Cloudy, but storm-free conditions should prevail across the tri-
state area through the night. Lows will be mostly in the low 70s.
&&
.PREV DISCUSSION [748 PM EDT]...
.SHORT TERM [Sunday Through Monday Night]...
Sunday morning starts out with the frontal boundary laying from SW
to NE from New Orleans through Morristown, TN with widespread
showers and storms along and ahead of it. These will spread east
through the morning with timing differences noted in the hires
guidance. Confidence is increasing that we will get scattered
severe storms early afternoon through the late evening hours. The
12z HRRR is notably quicker than other guidance with most in
agreement that storms reach the SE AL counties by 15z, with the
storms perking up as they move east during peak heating. Any
overnight precip should stay mostly to our west, leaving us able
to destabilize and prime for strong to severe storms. Plenty of
instability is available as well as some backing of the low level
winds creating looping hodographs. Limiting factors are the weak
low level shear (bulk shear is decent, 30-40kts) and the strongest
upper lift will pass to the north (which agrees with SPCs slight
risk staying in the northern parts of the area). Damaging wind
gusts and even the possibility for some hail are the highest
threats. Can`t rule out a weak tornado but the storm would need to
run into some boundary to enhance the low level shear.
With the upper low up in in N. AL and moving slowly east, the front
looks to stall on Monday west to east across the FL panhandle or
just offshore. Showers look to linger overnight Sunday night with
additional development on Monday. Showers and storms should stay
around Tallahassee and areas south and east, in the vicinity of the
front. Still uncertain on how unstable we will be Monday with all
the showers/cloud cover but strong thunderstorms are possible.
Showers/storms should move out after midnight Monday night.
.LONG TERM [Tuesday Through Saturday]...
Dry weather returns briefly on Tuesday as high pressure settles in
at the surface and northwesterly flow aloft. An upper trough will
dig into S. Texas through the end of the week which will drag a
boundary out east into the Gulf. A ridge will also start to build
over the local area so that will help keep the long term dry.
Temps will start warming up from the lower 80s Tuesday to the upper
80s Wed through Sat. Lows will be in the 60s.
.AVIATION...
[Through 00Z Monday]
Conditions have improved to VFR this evening and will remain so
until around 09z, when cigs and vsbys could drop to IFR near TLH,
DHN and VLD. IFR-MVFR conditions are possible at ECP and ABY as
well, but confidence is lower there. Another round of
showers/storms will move in with a cold front late starting around
15Z near ECP/DHN, storms will move further east through the TAF
period.
.MARINE...
Winds remain around 15 knots out of the south southwest until
shifting westerly behind a front Monday into Monday night.
Widespread showers and thunderstorms will continue through the
frontal passage with lingering showers and storms over the
offshore waters through the week. Seas will be able to diminish to
1 to 2 feet through the week with winds remaining around 10 to 15
knots.
.FIRE WEATHER...
Showers and thunderstorms will continue off and on overnight with
widespread showers and thunderstorms moving west to east across
the area Sunday. They will linger in the southern half of the
region Sunday night into Monday before clearing the area Monday
night. Minimum RH values will be high with transport winds as high
as 20-25MPH Sunday and around 10 MPH on Monday.
Fog Potential and Other Remarks...patchy fog is possible Sunday
morning.
.HYDROLOGY...
Widespread showers and thunderstorms are expected to continue
through Monday. Basin average rainfall amounts will be around a
half an inch to an inch but locally higher amounts up to 2 inches
will be likely.
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 71 86 70 85 62 / 10 70 50 50 10
Panama City 74 81 72 81 66 / 10 70 50 40 10
Dothan 70 82 66 82 59 / 20 80 40 10 0
Albany 70 84 68 82 60 / 20 80 40 20 10
Valdosta 71 86 70 84 61 / 10 80 40 50 10
Cross City 72 87 73 83 65 / 10 50 50 60 20
Apalachicola 75 82 73 81 66 / 10 60 50 60 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk until 11 PM EDT /10 PM CDT/ this evening
for Coastal Bay-Coastal Franklin-Coastal Gulf-South Walton.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Nguyen
SHORT TERM...LN
LONG TERM...LN
AVIATION...Nguyen
MARINE...LN
FIRE WEATHER...LN
HYDROLOGY...LN