Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/22/21
Area Forecast Discussion
National Weather Service Gaylord MI
1150 PM EDT Mon Jun 21 2021
.UPDATE...
Issued at 945 PM EDT Mon Jun 21 2021
Stratocu has peeled out of most of northern MI, with mostly clear
skies and gradually diminishing winds. It most emphatically does
not feel like the 1st full day of summer, but oh well. It is still
one of the shortest nights of the year, and this is good, because
our set-up for potential frost in some areas is...impressive. The
window for radiational cooling is even shorter than implied
above, as accas-type clouds (already present upstream in western
upper MI and WI) should provide partial cloud cover overnight in
northern/ western sections. That said, a number of places are
already starting out in the upper 40s, with surface dew points of
35-37f not providing too much of an obstacle. Could make a very
good argument for a frost advis for the usual colder interior
counties of northern lower MI. If anything, it`s probably just too
late to pull the trigger on that. Areas of frost will continue to
appear in the gridded forecasts, and in the Haz Wx Outlook.
That upstream accas deck is going to try to bring some sprinkles
or even light showers with it. Most near-term guidance is dry, but
recent RAP runs do spit out a touch of QPF from ISQ to PLN and
Rogers. Will refrain from adding a mention of precip.
&&
.NEAR TERM...(Through Tonight)
Issued at 335 PM EDT Mon Jun 21 2021
...Winds and Frost...
High Impact Weather Potential...Patchy to areas of frost are
possible tonight in low lying inland areas.
Pattern Synopsis/Forecast...With the last hurrah of the storm from
yesterday and last night, the cold front exited, ushering in cool
winds from the north west. With the 850 mb temperatures falling to
around 0C and water temperatures around 15C over Lake Michigan, we
have been having a cool, damp, breezy day, that would be more
representative of late September, than late June. However, as the
low continues to move out, the sfc high will build into the region,
and the 850 mb temperatures will rise a bit overnight. With a
slackening pressure gradient to diminish the winds, the moisture
leaving with the system, diminishing the clouds, temperatures will
fall into the mid to upper 30s over most of N Lower and E Upper. The
question then becomes do we decouple and lower the winds to less
than 4 mph? Also, The next system, and its moisture drops into the
region by 12z/Tues, pushing some mid clouds into the region. so the
question is do we get front from the clear to partly cloudy sky? and
do we drop enough to form frost. Think that based on recent
guidance, the winds drop to around 4-8 mph, and the isolated, low-
lying locations, could get patchy frost. Think that at most there
will be areas of frost south of M-32, and with the cloud cover
trying to make it in here, that we keep areas north and west of
there, out of the frost, and what frost we do get is not widespread
enough for a headline.
&&
.SHORT TERM...(Tuesday through Thursday)
Issued at 335 PM EDT Mon Jun 21 2021
...Cool with showers through midweek. Thunder Tuesday?..
High Impact Weather Potential: A few thunderstorms possible Tuesday.
Severe storms are not anticipated.
Larger scale but somewhat progressive trough is in the process of
deepening across eastern Canada and the Great Lakes today, bringing
an unseasonably cool airmass into the region, more akin to October.
Several embedded short-waves noted within the larger scale trough;
one sliding through the northern lakes today and second rotating
into Lake Superior. Third wave is sliding into Manitoba and will be
moving through our area on Tuesday.
At the surface...deepening sfc low and attending cold front is in
process of departing to the east/northeast of the region followed by
a large expanse of high pressure building into the Midwest and
Plains.
Respectably deep upper level trough will progress through the Great
Lakes region through Tuesday night along with a core of fairly cool
air aloft (-26C at 500 MB slides through during the day Tuesday). In
concert with the aforementioned wave, background QG-forcing for
ascent sliding through and daytime heating, it`s a good bet that we
see a bit of shower activity rotating through the region on Tuesday
into Tuesday evening...again more akin to October weather. Next
question revolves around the possibility of thunderstorms. Afternoon
forecast soundings depict a few hundred J/Kg of MLCAPE across the
region with convective depths up through -20C, particularly across
eastern Upper and northeast Lower Michigan. Thus, thunder chances
appear in order for tomorrow afternoon. Slightly stronger winds to
tap aloft and inverted V sounding down low might lead to some gusty
winds with any stronger updrafts. But severe weather threat is low.
Spotty shower activity carries into Wednesday. Upper trough and core
of colder air progresses eastward out of the region for midweek with
SW flow developing down low and warming temperatures aloft leading
to a bit more stable regime Wednesday. Soundings do suggest a thin
sliver of MLCAPE Wednesday afternoon, perhaps enough to support some
isolated showers in spots but no thunder.
Rounding out the short term...larger scale troughing begins to get
reinforced across south-central Canada with arrival of few more
pieces of short-wave energy. Surface low pressure is expected to
deepen across Ontario with another boundary sliding through the
Midwest and leaning into the far W/NW Great Lakes heading into
Thursday...along with another plume of respectable moisture/PWAT
also leaning into the region (in excess of 1.5 inches). Combined
with decent warm advection through the western Great Lakes, looks
like we will get another opportunity for some rainfall across the
region...perhaps as early as Wednesday night, although better
chances come Thursday and Friday. Possibilities are there for some
decent rainfall if everything comes together. But given our recent
track record with rainfall, won`t get too bullish with pops/QPF at
this juncture.
.LONG TERM...(Thursday night through Monday)
Issued at 335 PM EDT Mon Jun 21 2021
High Impact Weather Potential: Low for now
Strong troughing will be in place across the eastern half of Canada
as upper-level ridging centers itself over the Pacific NW heading
into the weekend. A shortwave embedded in the main flow may progress
over the Great Lakes in the Thursday night/Friday timeframe,
bringing northern Michigan its next chance for a more substantial
rainfall. Given current drought conditions, relatively high
uncertainty exists in any precip forecast several days out -
especially one with widespread rain chances. However, favorable
ascent aloft combined with a very moist atmosphere (PWATs
potentially pushing 2") at least has the chance to bring a more
substantial rainfall to the area other than typical summertime pop-
up showers and storms. Otherwise, temperatures look to remain close
to normal heading into next week as most should see highs in the mid
70s to low 80s.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1150 PM EDT Mon Jun 21 2021
SHRA/perhaps TSRA return Tuesday.
VFR conditions presently, with cool but relatively dry air in
place. A cu field will blossom quickly on Tuesday, and some
showers can be expected, especially in n central and ne lower MI
(APN, perhaps PLN). A few afternoon TSRA are possible, and again
APN has the best chance.
Westerly winds will become a touch gusty on Tuesday.
&&
.MARINE...
Issued at 335 PM EDT Mon Jun 21 2021
High Impact Weather Potential: Low for now
Strong troughing will be in place across the eastern half of Canada
as upper-level ridging centers itself over the Pacific NW heading
into the weekend. A shortwave embedded in the main flow may progress
over the Great Lakes in the Thursday night/Friday timeframe,
bringing northern Michigan its next chance for a more substantial
rainfall. Given current drought conditions, relatively high
uncertainty exists in any precip forecast several days out -
especially one with widespread rain chances. However, favorable
ascent aloft combined with a very moist atmosphere (PWATs
potentially pushing 2") at least has the chance to bring a more
substantial rainfall to the area other than typical summertime pop-
up showers and storms. Otherwise, temperatures look to remain close
to normal heading into next week as most should see highs in the mid
70s to low 80s.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY until 3 AM EDT Tuesday for LHZ347>349.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JZ
NEAR TERM...JL
SHORT TERM...BA
LONG TERM...DJC
AVIATION...JZ
MARINE...JL
Area Forecast Discussion
National Weather Service Denver/Boulder CO
926 PM MDT Mon Jun 21 2021
.UPDATE...
Issued at 918 PM MDT Mon Jun 21 2021
Forecast is on track, but we`ve decided to add some smoke both at
the surface and aloft since we`re getting prodigious smoke
production from fires south of Eagle (drifting across Park county) and
near the northwest corner of Colorado (plume headed straight for
Denver but it`s not here yet). The surface smoke should be mainly
over the mountains where the plumes intersect the terrain, but I
have no reason to doubt the HRRR output that does produce some
increase in surface smoke down into Denver by morning. Hard to
tell how long that will last--Denver seems to be about 6-8 hours
downwind of the fire so if the fire behavior moderates the plume
should be less by morning and the surface smoke should mix out in
the afternoon. Then we get the next round. There`s probably not
enough for this to be a big deal yet, but it will be noticeable.
And probably not enough to bring our temperatures down
significantly either.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 245 PM MDT Mon Jun 21 2021
Cool temperatures will continue this evening with widespread fair
weather cumulus clouds around the area. Model forecast soundings
have continued to trend slower with the breakup of clouds, so what
you see now is what you`ll like see through the rest of the
afternoon. Highs will peak in the upper 60s to mid 70s across the
plains. Not much diurnal cooling is expected overnight tonight,
while we see fairly robust mid-level warm air advection. Lows
should drop into the 50s over the plains and cooler for the higher
elevations.
The cool weather we have today will be a distant memory by
tomorrow afternoon. Increasing westerly flow aloft along with
700mb temperatures rising up into the +16 to +20C range should
lead to highs reaching the low to mid 90s over the Denver metro
and most of the plains. Soundings show very little moisture to
work with, so only a few clouds are in the forecast. The main
concern tomorrow will be for increasing fire danger, especially
over our western counties. More detailed information is provided
in the fire wx discussion below, but the bottom line is that very
dry and breezy conditions are likely during the afternoon hours
across Grand and Jackson counties.
We could also begin to see some smoke from the ongoing western
Colorado wildfires by tomorrow evening with generally westerly
flow aloft. This will be dependent on fire behavior during the
afternoon tomorrow, but HRRR Smoke forecasts indicate increasing
concentrations of smoke aloft by the late evening hours.
.LONG TERM...(Tuesday night through Monday)
Issued at 245 PM MDT Mon Jun 21 2021
A ridge of high pressure over the Rocky Mountain Region will
bring a return of hot and mostly dry conditions to the forecast
area. 700 mb temperatures warm back to around 16.5C which will
translate to around 97F for Denver. Minimal thunderstorm
development with strong mid level subsidence, but could still be
some isolated high based thunderstorm coverage late in the afternoon
with gusty winds the main issues in and around South Park.
Wednesday night into Thursday, the ridge shift more to the south
and east of Colorado with the flow aloft becoming southwesterly.
Mid and upper level moisture will increase ahead of a closed low
off the northern CA coast. A weak short wave appears to get eject
from this system and move across northern CO late Wednesday night
into Thursday. This will result in some cooler as well as a better
chance of showers and thunderstorms across the cwa with wetting
rainfall. Another short wave will drop out of the northern Rockies
Friday into Saturday, bringing even cooler temperatures and a
better chance of showers and thunderstorms. High temperature on
Friday will be closer to 79F. Upslope conditons will develop
along the the Front Range and Palmer Divide. This system has some
instability but it appears to be limited. Concern will be
elevated for the burn areas primarily due to the upslope slowing
down the storm motions. It will remain cooler and unsettled into
the weekend, with the focus of thunderstorms across the southern
and southwestern part of the cwa.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 918 PM MDT Mon Jun 21 2021
We`ve added a mention of smoke to the Denver area TAFs this
evening. Surface visibility is expected to stay above 6 miles, but
elevated smoke layers may impact slant visibility on approach to
KDEN at times, especially early Tuesday morning. Aloft the smoke
will be mostly northwest through south of Denver below 20,000 ft
MSL.
&&
.FIRE WEATHER...
Issued at 245 PM MDT Mon Jun 21 2021
...RED FLAG WARNINGS TUESDAY...
Much warmer and very dry conditions are likely across the high
valleys tomorrow, especially over Middle and North Parks. While
temperatures have been mild today, a very hot and dry airmass will
be overhead by late tomorrow morning. Temperatures will warm up
into the 80s by tomorrow afternoon with humidities falling to
about 12-15%. Forecast guidance suggests increasing winds through
the day with 30kt flow aloft mixing down to the surface. With
forecast confidence increasing, we`ve gone ahead and issued a Red
Flag Warning from noon to 7PM tomorrow for the lower elevations of
Grand and Jackson county, including Fire Weather Zones 211, 213,
and 217. Elsewhere, elevated fire danger is likely with dry
conditions most of the forecast area, but winds are expected to
remain below criteria and some zones have yet to reach critical
fuel status as well.
Fire Weather Watch has been issued for Fire Weather Zones 211, 213
and 217 for late Wednesday morning to early Wednesday evening, due
to low humidity, dry fuels under 15% and gusty winds to 35 mph.
The fire danger will be elevated over parts of Larimer County as
well, but lower confidence in the drier fuels there. Some cooling
and increasing moisture is expected Thursday into the weekend, but
elevated fire danger may continue west of the Continental Divide.
&&
.HYDROLOGY...
Issued at 245 PM MDT Mon Jun 21 2021
No hydro concerns tonight and tomorrow. Hot and dry weather is
likely tomorrow with about a 10 percent chance of an isolated
light shower or thunderstorm in the afternoon.
Wednesday will be mostly be dry with very low threat of flooding,
then precipitation chances increase Thursday into the weekend
with a low threat of flash flooding each day. The best chance of
significant rainfall looks to be Friday afternoon, and the
greatest threat would be for burn areas in the mountains and
foothills east of the Continental Divide.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon to 7 PM MDT Tuesday for COZ211-213-
217.
Fire Weather Watch from Wednesday morning through Wednesday
evening for COZ211-213-217.
&&
$$
UPDATE...Gimmestad
SHORT TERM...Hiris
LONG TERM...Cooper
AVIATION...Gimmestad
FIRE WEATHER...Hiris/Cooper
HYDROLOGY...Hiris/Cooper
Area Forecast Discussion
National Weather Service Caribou ME
1038 PM EDT Mon Jun 21 2021
.SYNOPSIS...
A cold front will approach overnight and cross the area on
Tuesday. High pressure will settle over the area by the middle
of the week and slide offshore on Thursday. Another system will
approach from the west late in the weekend.
&&
.NEAR TERM /THROUGH TUESDAY/...
1035 PM Update: Convection is winding down as instability has
weekend as noted by the latest LAPS data showing lapse rates
weaken. Latest meso-analysis showed Theta E ridge in place
across the northern and central areas, but showed signs of
weakening shirting s. The last few runs of the HRRR did show
convection winding down this evening w/just showers overnight
from time to time. Some adjustments were done to the pops for
placement showing the highest percentages across the w and nw
overnight. Kept the mention of the fog in the forecast into
Tuesday morning given the heavy rainfall this afternoon`s
convection which produced a good round of svr storms w/some wind
damage. Dense Fog Advisory for the coast remains in place. Overnight
temps were tweaked to keep readings in the 60s.
Previous Discussion...
The cold front will slowly cross the region on Tuesday from
northwest to southeast across the region. Expect scattered
showers as the front crosses the region. The best chances for
thunderstorms will be across east central and Downeast portions
of the region. It will be cooler with highs ranging from the
lower 70s across the north and mid 70s Downeast.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
Cold front wl be along the coast on Tue evening and likely to move
offshore by 03z. However showers likely to continue over Downeast
until daybreak as upr lvl jet finally east moves into New Brunswick.
Skies wl clear with drier air mvg in behind and min temps wl dip
into the 40s with possibly u30s in far nwrn Aroostook.
Clear skies will be on tap thru the end of the short term with high
temps on Wed below normal before rebounding to just above normal for
Thursday. Thursday wl feature high pressure sliding offshore with
return flow drawing in more moist air and temps topping out in the
u70s/nr 80F. Given clear skies and fairly light winds expect patchy
fog to dvlp briefly each morning.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Bermuda high will likley keep next system at bay thru Sat morning.
Temped to rmv pops from Sat but with global Canadian indicating pcpn
over the area in the aftn hv opted not to remove. Hv also retained
mention of thunder in the afternoon and evng, however have
dropped chcs to slgt chc as main forcing rmns back to the west.
Cdfnt looks to be approaching the international border by Sun
morning though guidance differs on timing and additional waves
riding northeast along the bndry. Bndry appears to stall out at some
point early next week as an active pattern looks to set up.&&
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: VFR conditions early will give way to widespread IFR/LIFR
in low clouds and areas of fog, especially KBGR/KBHB vicinity.
Scattered thunderstorms will mainly affect the northern
terminals through early this evening. Widespread IFR conditions
are expected Tuesday morning to give way MVFR, then VFR in the
afternoon. Scattered thunderstorms are possible in the
afternoon, mainly KHUL south. S wind around 10 kt this evening,
becoming W around 10 kts on Tuesday.
SHORT TERM:
Tue night...VFR over northern terminals with IFR improving to
VFR Downeast late. NW 5-10kts.
Wed...VFR. 5-10kts.
Wed night...VFR. Light WSW.
Thu-Fri night...VFR. S 5-10kts and gusty each afternoon.
Sat...VFR becoming MVFR in the afternoon. S 5-15kts.
&&
.MARINE...
NEAR TERM: Winds/seas will generally remain below SCA levels, although
a few gusts to around 25 kt are possible tonight. Visibility will
be reduced to less than 1 NM in areas of fog.
SHORT TERM: Seas and winds remain below SCA thresholds. Patchy
fog likely to reduce visibilities over the waters thru the end
of the week.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Dense Fog Advisory until 8 AM EDT Tuesday for MEZ029-030.
MARINE...None.
&&
$$
Near Term...Hewitt
Area Forecast Discussion
National Weather Service Corpus Christi TX
701 PM CDT Mon Jun 21 2021
.DISCUSSION...Updated aviation discussion for 00z TAF cycle.
&&
.AVIATION...
VFR conditions will continue through the evening before a weak
cold front pushes into the Coastal Bend overnight. This will
produce occasional showers and thunderstorms, some of which may
reduce ceilings and visibilities. Surface winds away from
thunderstorms will become light and variable, eventually turning
more persistently northerly as the boundary arrives in our neck of
the woods. Chances for elevated showers and thunderstorms will
continue behind this boundary, gradually ending from west to east
on Tuesday.
&&
.PREV DISCUSSION... /Issued 348 PM CDT Mon Jun 21 2021/
SHORT TERM (Tonight through Tuesday Night)...
Cloud cover was slow to diminish over the northern Brush Country
this afternoon and has limited heating there. Cancelled the
Excessive Heat Warning for areas from Cotulla to George West and
issued a Heat Advisory to replace it until 00Z. Kept the warning
going for southern parts where clouds have cleared and warming
has occurred with heat index values near 115 at this time.
Cold front was located from south of the DFW metroplex west to the
Permian Basin. Convection along the boundary is limited at this
time, but hi-res ensemble members show activity should increase
from central Texas west to the Concho Valley late this afternoon.
This activity is expected to move south through the evening hours.
Storms over southeast Texas will push southward toward the coast
this evening also. Plenty of moisture and instability will be in
place across south Texas for storms to maintain themselves in the
northerly flow aloft. MLCAPE values will range from 2000-3000 J/kg
and latest RAP model shows 0-3 km shear vector from the north at
30 knots. SPC maintained the Marginal risk of severe storms across
the extreme northern portions of the forecast area for tonight.
Storms will have the potential to produce strong gusty winds.
Outflow from storms will push the effective frontal boundary down
to the coast Tuesday morning. Expect convection will linger over
the coastal plains and southern Brush Country in the morning
before pushing mainly offshore in the afternoon. Temperatures will
be cooler behind the front with highs slightly below normal.
Upper level ridge will be over southwest Texas Tuesday afternoon
into Tuesday night and bring in drier air to the region from the
north. Moisture will remain over the Gulf waters Tuesday night
with additional scattered showers or thunderstorms possible.
LONG TERM (Wednesday through Monday)...
Dry and hot conditions can be expected for the second half of the
week as a mid/upr level ridge builds over the state. Cannot rule out
a few sea breeze showers on Wednesday as 2" PWATs linger along the
coast. Expect heat indices in the 105-109 range with a few locations
over the northern brush country possibly reaching 110. Moisture
begins to increase on Saturday as a trough begins to drop into the
Southern Plains and a tropical wave/inverted trough moves into
the central gulf. Expect iso/sct sea breeze showers on Saturday
across the gulf and northeast Coastal Bend. Rain chances improve
Sun/Mon as the mid/upr level ridge shifts west and the tropical
wave moves into South Texas. Temperatures will not be as hot Sat-
Mon with the increased cloud cover and precipitation in the area.
Heat Index values will generally be below 105.
MARINE...
Moderate onshore flow this evening will become light as a frontal
boundary approaches south Texas. Showers and thunderstorms will
become scattered to numerous late tonight into Tuesday ahead of
the frontal boundary. The weak frontal boundary will sag into
South Texas but stall before reaching the coast Tuesday morning. A
weak onshore flow will continue over the Gulf waters Tuesday into
Tuesday night. Isolated to scattered showers and storms will be
possible Tuesday night.
The onshore flow becomes moderate to strong by the end of the week
as low pressure strengthens in the Southern Plains. Isolated showers
and thunderstorms will be possible Wednesday and again Saturday.
Scattered showers and thunderstorms are possible Sunday and Monday
as a tropical wave moves into South Texas.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 78 91 78 93 79 / 60 60 20 20 10
Victoria 76 90 76 92 78 / 50 50 20 30 10
Laredo 79 95 78 101 78 / 40 40 10 10 10
Alice 78 92 76 95 76 / 50 60 20 20 10
Rockport 80 90 80 92 81 / 60 60 20 20 10
Cotulla 77 93 77 101 78 / 40 30 10 10 10
Kingsville 78 91 77 94 77 / 60 60 20 20 10
Navy Corpus 81 88 81 90 82 / 60 60 20 20 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory until 7 PM CDT this evening For the following
zones: Bee...Coastal Kleberg...Coastal Nueces...Coastal
Refugio...Coastal San Patricio...Goliad...Inland Calhoun...
Inland Refugio...Inland San Patricio...La Salle...Live
Oak...McMullen...Victoria.
Excessive Heat Warning until 7 PM CDT this evening For the
following zones: Duval...Inland Kleberg...Inland Nueces...
Jim Wells...Webb.
GM...None.
&&
$$
JV/71...AVIATION
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
302 PM PDT Mon Jun 21 2021
.SYNOPSIS...Cooler temperatures are forecast for the interior through
mid week as an upper level low meanders around offshore. In addition
to the cooling, this upper low will also bring a slight chance of
thunderstorms in the interior Tuesday and Wednesday. A warming
trend is forecast for the interior toward the end of the week.
&&
.DISCUSSION...A southeasterly speed max with higher mid layer
moisture has been moving across the Trinity County this
afternoon. Terrain induced wave clouds were apparent on visible
imagery indicative of the stable nature of the atmosphere. Another
speed max will develop later tonight aimed at NE Trinity County.
The atmosphere appears too stable with elevated CAPE generally
under 100J/kg. SREF calibrated thunderstorm probabilities are
around 10% this evening and 5% overnight, while HREF neighborhood
probabilities of 20% or more stay just north of the area through
the night. Convective allowing models, such as the HRRR and NAM-
nest has the convection firing up well north and northeast of the
area tonight, however a few isolated lightning strikes near the
tip of NE Trinity County is not completely out of the question,
though unlikely to occur.
Convective parameters look slightly better for storms on Tuesday,
however once again soundings indicate a fair amount of CINH to
overcome. SREF and HREF neighborhood probabilities do increase
near the Siskiyou County border, and a few lightning strikes
appear possible for NE Del Norte and the mountains of northern
Trinity Counties. Less probable is storms over South Fork Mountain
and Yolla Bolly Mountains where soundings are more stable.
The offshore low will slowly edge closer to the coast from
the southwest on Wednesday. This seems to be the best day for
thunderstorms across the area. The soundings still do not look all
that great, but the GFS soundings has higher surface based CAPE
with equilibrium levels colder than -20C. The southeasterly flow
aloft is a favorable pattern for storms to form farther west out
toward eastern portions of Humboldt and Mendocino County, in
addition to the mountains of Del Norte and Trinity Counties. NAM
soundings do indicate elevated CAPE of 150-250J/kg by Wed evening
over the coast and coastal waters as mid level moisture of debris
clouds spread northwestward over the coast. The lower level
marine environment will likely make storm prorogation out over the
coast unlikely. This will need to be watched closely. Convective
allowing models should shed more light on this once within range,
about 24-48 hours out.
The cut-off low should start to meander southward on Thursday.
Southeasterly-easterly flow aloft and wrap around moisture may
bring another threat of storms on Thu, primary for SE Trinity and
NE Mendocino Counties.
ENS and GFS ensemble means clearly show a massive 500mb height
anomaly extending into the Pacific NW toward the latter portion of
the week and over the weekend. All WPC 500mb clusters show this
pattern to one extent or another, with a cut-off low somewhere,
either offshore to our southwest, over northern California or
south offshore Central/Southern California. Bottom line, if the
low lingers over or in the vicinity of northern California during
the latter portion of the week, temperatures will not warm up as
much or as quickly as the GFS indicates. We may even see multiple
days of interior storms through Friday.
ENS and GEFS probabilities for 850mb temperatures of 25C or more
increase Sunday and Monday. Widespread triple digit heat is
probable for many of the interior valleys once again. Looking at
the National Blend of Models, the strongest warming appears to
occur in the northern most portion of the forecast area, at least
initially, the ridge extends southward into the forecast from the
north. There is still about 10F degrees of mid spread, 95-105F,
for places like Hoopa and Weaverville. A few hotter valley spots
could hit 108 to 112F again. High heat risk is expected for the
valleys both Sunday and Monday.
&&
.AVIATION...IFR/LIFR ceiling and visibility restrictions prevailed
along the coast, coastal valleys and inner coastal range slopes
today. However by noonday, visibilities had generally lifted to
VFR. Most ceilings were IFR variable MVFR...especially in Del
Norte. The marine layered deepened but not sufficiently to top
higher mountains and spill into the Ukiah`s mountain valley.
Stratus pushed northward from Sonoma to just miles south of Ukiah
this morning. This evening and overnight, similar IFR/LIFR
conditions (like this morning) will prevail at coastal terminals.
Overall, Inland valleys...including UKI remained VFR with breezy
south-southeast winds. A southerly push and possibly a deeper
marine layer may bring some lower Cigs into the Ukiah valley
overnight/Tuesday morning. /TA
&&
.MARINE...Winds and seas continue to diminish as an upper low
approaches. Winds have shifted to light, southerly breezes this
afternoon. Relatively light winds will persist across all waters,
allowing short period waves to diminish through Tuesday. Winds will
then pick up again to a moderate northerly breeze early on
Wednesday, with winds continuing to increase and move closer to
shore later in the week.
A southerly swell of 3 ft at 18 seconds is currently impacting the
area. A northwesterly swell of 2 to 4 ft will build in on Tuesday
and sporadically persist for the rest of the week.
&&
.FIRE WEATHER...Thunderstorm activity is expected to occur north
of the area tonight, though isolated lightning strikes will be
possible over far NE Trinity County near the Siskiyou County
border. The potential for storms will increase slightly on
Tuesday, once again mainly near Siskiyou County, though a few late
day strikes will be possible over South Fork Mountain and the
Yolla Bolly Mountains. The threat for isolated interior storms
will increase Wednesday afternoon and early evening. Lightning
activity is expected to be isolated at this time, so will continue
to use headlines in the fire weather planning forecast.
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...None.
NORTHWEST CALIFORNIA COASTAL WATERS...None.
&&
$$
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Area Forecast Discussion
National Weather Service San Angelo TX
616 PM CDT Mon Jun 21 2021
...New AVIATION...
.SHORT TERM...
(This evening through Tuesday)
Issued at 147 PM CDT Mon Jun 21 2021
As of early afternoon, a cold front was moving southward through the
Big Country and was located just north of I-20. The airmass south of
this boundary is fairly unstable with CAPE values of 4000-5000 and
lapse rates of 8-9 deg C/km. RAP soundings across our county
warning area show dry air from about 800mb-500mb and DCAPE values of
around 1000J/kg, which has the potential for damaging winds from wet
microbursts that may occur. PWAT values of 1.5-2.0 inches also
shows the potential for locally heavy rainfall after the initial
damaging wind threat. So the big question: Where will these storms
develop? Conventional wisdom and CAM solutions show activity
developing on or just ahead of the front as it pushes southward this
afternoon. The timing should intersect nicely with peak daytime
heating late this afternoon and evening, allowing storms to develop
into east-west multicell clusters along I-20, with another area in
the Concho Valley and Edwards Plateau. This activity should
continue southward in a fairly ragged fashion, and will move into
the Hill Country after sunset. Some post-frontal showers and a few
thunderstorms are possible, but the damaging wind threat should
subside by then.
Overnight, as the cooler air moves in, widespread cloud cover will
develop underneath the frontal inversion, mainly south of I-20. Lows
tonight should be about 10-15 degrees cooler than last night.
Tomorrow, the cooler airmass should remain in place with generally
northeast winds, turning east by afternoon. Overcast skies in the
morning should break up with heating by noontime. These factors
should allow high temperatures to be in the low to mid 80s, which
will be a welcome relief from the blast furnace conditions of the
last few days.
&&
.LONG TERM...
(Tuesday night through next Monday)
Issued at 150 PM CDT Mon Jun 21 2021
Upper level high pressure will return to West Central Texas Tuesday
night into Wednesday. Subsidence from this upper high will likely
result in sunny skies and afternoon high temperatures climbing into
the mid 90s by Wednesday. Temperatures will continue to climb
into the mid 90s to around 100, Thursday and Friday.
As the upper level high weakens on Saturday, afternoon high
temperatures shouldn`t be as warm. The ECMWF and GFS prog an upper
level high pressure system to build across the Western U.S. this
weekend. This type of pattern should bring upper level northerly
flow across West Central Texas early next week. This type of
pattern should bring cool frontal passages along with chances for
rain and below normal temperatures to the region by early next
week.
&&
.AVIATION...
(00Z TAFS)
Issued at 615 PM CDT Mon Jun 21 2021
Isolated to widely scattered thunderstorms are possible this
evening along the I-10 corridor and Heartland and have VCTS at
the southern terminals until 05-06Z. Expect MVFR ceilings to
develop at most of the terminals between 03Z-06Z and remain
through 18Z Tuesday. Also, going IFR at the KJCT site by 09Z
Tuesday. The winds will be north to northeast with gusts of 25 to
30 knots this evening.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 61 84 69 95 / 20 0 0 0
San Angelo 64 87 69 97 / 30 10 0 0
Junction 66 87 70 95 / 60 10 0 5
Brownwood 64 84 69 95 / 40 5 0 0
Sweetwater 61 85 69 95 / 20 0 0 0
Ozona 66 88 71 94 / 50 5 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...SK
LONG TERM....26
AVIATION...21
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
833 PM EDT Mon Jun 21 2021
.UPDATE...
Storms initiated along the sea breeze during this afternoon and
have now moved inland as large outflow from convection over
Florida Big Bend moves south across northern waters. We are seeing
the push from the southeast as expected this evening bringing
storms northward into central inland areas and expect these to
continue moving north/northwest for the next few hours before
dissipating. Will also continue to see some showers and storms
over the gulf waters possibly affecting coastal areas from the
Tampa Bay area north this evening, but these to will gradually
dissipate as the outflow weakens. Overall the current forecast
looks ok with no changes needed.
&&
.AVIATION...
Scattered convection will continue to move north, mainly affecting
just LAL with some areas of MVFR/local IFR conditions before
midnight. Later tonight into Tuesday morning VFR conditions are
expected to prevail then we`ll see more scattered convection
develop during the afternoon which could cause some MVFR/local IFR
conditions. Winds will become light southeast overnight then
increase to around 10 knots during Tuesday morning and shift to
southwest during Tuesday afternoon.
&&
.Prev Discussion... /issued 210 PM EDT Mon Jun 21 2021/
DISCUSSION (Tonight - Monday)...
Clouds have thinned out significantly over the last couple of
hours allowing for rapid surface heating and sea breeze
initiation. Isolated showers and storms are now developing inland
and moving toward the north and northeast. Expect storms to
become more numerous over the interior this afternoon with some
strong storms possible with gusty winds and some hail.
Models, including convection allowing models, continue to show a
southeasterly surge moving back across the peninsula and pushing
storms back toward the Gulf coast this afternoon and evening. The
latest HRRR now stops short of bringing convection back to the
west of the I-75 corridor, and this seems more likely given just
weak ridging moving back into the area from the southeast and no
clear change in steering flow. I will still leave mention of
storms for coastal areas this evening since even if the push
doesn`t make I-75, any outflow boundaries advancing northwestward
could initiate some convection.
As to the future, deep mid-level moisture is set to remain in
place over our region through at least Thursday. We have strong
upper-level ridging to our west over Texas and to our east over
the Atlantic. In between we have general troughing with cyclonic
flow. Weak perturbation in the flow will bring bouts of clouds
and showers, mainly impacting the Nature Coast. Afternoon heating
each day will result in scattered to numerous showers and storms
mainly inland each day.
By Friday - we see signs that the upper-level trough will weaken
allowing the Texas and Atlantic ridge to become more continuous
to our north. Also - We see the surface ridge axis lifting north
while tropical waves/inverted troughs move westward through the
Caribbean Sea. Assuming model trends are correct, the focus for
afternoon storms will shift to the I-75 corridor and the Gulf
coast.
MARINE...
A surface ridge of high pressure will build over the waters
tonight and remain in place through the end of the week. Some
showers and storms are possible at any time, but not expecting any
widespread coverage. Winds and seas will be light except in the
vicinity of showers and storms.
FIRE WEATHER...
Very high humidity remains in place with higher than normal storm
coverage over the interior expected for the next few days. No fire
weather concerns.
&&
.Preliminary Point Temps/PoPs...
TPA 79 91 79 90 / 30 50 10 60
FMY 76 93 75 91 / 30 40 20 60
GIF 76 92 75 90 / 60 70 30 70
SRQ 77 91 76 89 / 20 50 10 50
BKV 73 91 72 89 / 30 60 20 60
SPG 79 89 79 88 / 20 50 10 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.
&&
$$
UPDATE/AVIATION...Close
PREV DISCUSSION...Jillson
UPPER AIR/DECISION SUPPORT...Delerme