Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/01/18
Area Forecast Discussion
National Weather Service Gaylord MI
1029 PM EDT Sat Jun 30 2018
.UPDATE...
Issued at 1029 PM EDT Sat Jun 30 2018
Closed mid level high pressure system has migrated to the mid
Atlantic coast with mid level ridging stretching up through the
central lakes region. Impressive heat dome remains across the
Great Lakes with H8 temps >22C. But despite the warm temps and
high sfc dewpoints still out there, atmosphere across most of
this CWA remains capped owing to that warm nose and lack of
moisture centered around 800 mb per this evenings APX sounding.
Capping weakens heading west and north to the fringes of the heat
dome of course, as evidenced by ongoing convection stretching from
Iowa through Wisconsin and into western and central upper MI.
Tricky forecast once again tonight, centered on whether or not we
get any of the upstream convection into our area. Per radar
trends, eastern upper MI has the better chances as ongoing
showers/storms in central upper are continuing to slowly inch
eastward toward Chip/Mack counties.
Less certain for northern lower Michigan. Guidance continues to
weaken the capping across the CWA as mid level ridging eases off
to the east and warm nose around 800 MB cools a few degrees. No
larger scale forcing mechanisms at play. But any smaller scale
forcing/ripples propagating out of the upstream convection could
touch of some showers/thunder over parts of northern lower
Michigan during the overnight hours as suggested by several high-
res guidance solutions. So, will continue the inherited forecast
idea of easing PoPs into the area.
Despite respectable instability (>3500 MUCAPE on 00Z sounding),
stronger flow aloft/bulk shear values remain just to our north.
There are some stronger cells across the U.P. and Lake Superior
that could pose a severe weather threat to the EUP. Not so much
south of the bridge however.
Otherwise, and very warm night ahead with lows spanning the 70s in
northern lower MI. A little cooler in eastern upper Michigan.
&&
.NEAR TERM...(Through Tonight)
Issued at 351 PM EDT Sat Jun 30 2018
...Steamy with a few storms...
High impact weather potential...blazing heat/humidity into evening.
A few strong/severe storms possible nw lower/eastern upper MI.
An impressively and dangerously hot/muggy day across northern MI.
Temps range thru the 90s in most of northern lower MI, and have
little doubt that a few sites have or will touch 100f. Equally
impressive were surface dew points being very reluctant to lower
even as mixing deepened. We are finally seeing a few interior
spots see dew points lower into the upper 60s (GLR/Grayling), but
low/mid 70s are still far more prevalent. Dangerous heat indices
of 100 to 110f are thus quite common in northern lower, with TVC
unfortunately as bad as anyone. Eastern upper MI has been held
back by more in the way of cloud cover, but that is finally
departing as a small cluster of convection heads east from
Superior. Their warmest heat indices up there today are still yet
to come.
A series of low pressure systems is found over southern Canada. A
weak cold front drapes from one of these across western Superior and
western upper MI into northern WI and far se MN. Most of the
convection is on the cool side of the front, as warm air aloft keeps
the warm sector capped. However, that changes tonight as the 500mb
ridge axis shifts toward the eastern lakes, resulting in falling
heights/temps aloft and a weakening of the cap. Best chance of us
seeing some showers/storms evolve into here will be after dark (10-
11pm). This is largely in agreement with the last couple of SPC HRRR
runs and the going forecast, though have accelerated the onset of
higher pops in nw lower/eastern upper MI by a few hours. This is
obviously past peak heating, but a few stronger (but poorly
organized) updrafts are progged, mainly a couple hours either side
of midnight, and again for nw lower/eastern upper MI. We remain
in a marginal risk for svr from Ltl Trav Bay northward, and that
will continue to be mentioned in the HWO. Hard to go with more
than sct/chancy pops though.
Temps will slowly/steadily fall off, with any spotty convection
hastening that process. Have gone above guidance temps, which are
struggling with how anomalous this airmass is. Lows in the low/mid
70s will be most common, though TVC and a few other spots will
hang in the upper 70s.
&&
.SHORT TERM...(Sunday through Tuesday)
Issued at 351 PM EDT Sat Jun 30 2018
...Warm and humid with a continued chance of thunderstorms...
High Impact Weather Potential: The potential continues for
thunderstorms, some possibly severe, Sunday and early Monday
morning. Chances for another round of heat index over 100 degrees on
Sunday?
Primary Forecast Concerns/Challenges: Will be assessing the
atmospheric conditions and expected forcing over northern Michigan,
as a weakening boundary lifts northeast across Wisconsin and the
overall chances for severe weather Sunday and early Monday.
Pattern Synopsis/Forecast...The storm system organizing over the
central Plains since Friday, will weaken and eventually slowly push
east into the Great Lakes Sunday. This system will exit northeast
into Quebec on Monday. Pcpn and chances for thunderstorms will be
hindered across the forecast area thru Sunday afternoon, mainly due
to weak forcing with the approaching boundary and mid lvl cap in
place (700mb temps warm to nearly 13c). 850/500mb qvector
convergence shows the best forcing with the system confined to areas
around the tip of the mitt, Upper Michigan and Lake Superior. These
areas will also have a better chance of pcpn, being located on the
edge of the 700mb cap into Sunday Afternoon. However 700mb temps
across Lower Michigan do diminish between 21z Sunday and 06z Monday,
as the strong ridge that had been in place over the ern one third of
the country pushes east, while a weak upper trough drops into the
upper Midwest. Additional support for thunderstorms Sunday evening
and early Monday will be 0-3km cape values lingering around 2500
J/kg after the 700mb cap decreases and mid level lapse rates
increase to 7 c/km. Some additional forcing will be supplied by the
right entrance region of a weak 300mb jet Sunday evening. A few
strong storms are expected with heavy rain (pwat over 1 inch) and
hail limited to around 1 inch (freezing lvls near 16k ft with weak
vertical wind shear).
Pcpn chances diminish greatly by 12z Monday with some sun and dry
conditions expected through Tuesday across northern Michigan, as
surface and upper lvl ridging redevelop over the Great Lakes. High
temperatures in this pattern will remain above normal across
northern Michigan, with highs mainly around 90 degrees.
Overall will hold off on issuing another heat related headline for
northern Michigan Sunday, as increasing clouds will hold
temperatures down a tad, helping keep afternoon heat index values
below 100 degrees.
.LONG TERM...(Tuesday night through Saturday)
Issued at 351 PM EDT Sat Jun 30 2018
A warm pattern to remain over the region through the forecast period
as surface and upper level ridging largely remain centered over the
Great Lakes and Atlantic coast into next weekend. A warm boundary
will pass quickly over the Great Lakes and Ontario Thursday
generating a chance of thunderstorms across northern Michigan. Mid
level temperatures do cool by the end of the forecast period,
falling from around 17c earlier the week to around 12c Saturday as a
500mb trough deepens over the north Atlantic. overall will keep
afternoon high temperatures 85 to 90 degrees through Friday with
temperatures cooling to more seasonal levels in the upper 70s next
weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 849 PM EDT Sat Jun 30 2018
Dome of heat remains across lower Michigan southward into the Ohio
Valley. But despite the heat, atmosphere remains capped to
showers/storms owing to a nose of very warm air and limited
moisture in the lower levels of the atmosphere. Lots of active
weather (showers and storms) continues to our west and northwest
from Wisconsin into the western U.P. along the fringes of the
heat dome where atmosphere is less capped. Low level capping will
weaken through tonight and allow some of that activity to sneak
into northern lower Michigan overnight, although it will likely
weaken as it does so. But I do have a few hours of VCSH/VCTS at
the NW lower MI terminal sites.
Otherwise, VFR weather anticipated for much of the night with
thickening mid and high cloud spreading into the region from
upstream convection. But similar to last night, SCT-BKN stratus
might materialize late overnight and persist into Sunday morning.
Forecast confidence in this occurring is not great, but I did
include SCT lower cloud cover at some of the sites.
Sunday, expect much more daytime CU development (35-50K feet) and
a few pop-up showers are possible. Cold front swings into the
region late in the day into Sunday night and will bring a line of
showers and storms through the region.
&&
.MARINE...
Issued at 351 PM EDT Sat Jun 30 2018
Gusty southwest winds this afternoon, will diminish below small
craft advisory across northern Lake Michigan nearshore waters this
evening. However, gusty southwest winds are expected to redevelop
across the western Great Lakes once again Sunday, as a storm system
in the Plains pushes east. Thunderstorm chances will increase across
the northern Great Lakes Sunday and early Monday, as the Plains
storm system quickly passes over the state. Some sun and drier
conditions are expected Monday afternoon and Tuesday as high
pressure rebuilds over the region.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...EXCESSIVE HEAT WARNING until 8 AM EDT Sunday for MIZ016>036-041-
042.
HEAT ADVISORY until 8 AM EDT Sunday for MIZ008-015.
LH...NONE.
LM...SMALL CRAFT ADVISORY until 11 PM EDT this evening for LMZ341-
344>346.
LS...NONE.
&&
$$
UPDATE...BA
NEAR TERM...JZ
SHORT TERM...SR
LONG TERM...SR
AVIATION...BA
MARINE...SR
Area Forecast Discussion
National Weather Service La Crosse WI
954 PM CDT Sat Jun 30 2018
.UPDATE...
Issued at 954 PM CDT Sat Jun 30 2018
Concerning additional rainfall and possible flooding overnight,
re-issued the Hydrologic Outlook to highlight possible threats.
Roughly 1-3 inches fell across parts of northeast IA, southeast
MN, and west-central WI this evening. Latest CAMs suggest heavier
convection currently across central IA should weaken as it drifts
northward overnight. This tends to make sense as these areas
should be worked over from the evening convection. RAP also shows
the best MUCAPE and mid-level moisture transport overnight to the
east of areas that have already received heavier rain. This isn`t
to say flooding or flash flooding isn`t possible overnight, but
not enough confidence to hoist a Flash Flood Watch. Right now, an
additional inch or more looks possible. Will continue to monitor
and adjust forecast as necessary.
UPDATE Issued at 732 PM CDT Sat Jun 30 2018
Heat headlines were allowed to expire at 700 PM as showers and
thunderstorms across the area have resulted in temperatures
falling dramatically. The heat threat has ended.
Showers and thunderstorms will continue through the evening, some
of which may be severe with the primary threat being damaging
wind.
&&
.SHORT TERM...(Late Afternoon through Sunday)
Issued at 240 PM CDT Sat Jun 30 2018
Ready for relief from the heat? We can see it not that far away, in
the wake of a cold front currently draped from the western U.P of
Michigan down through northwest Iowa as of early afternoon, though
in spots "augmented" by remnants of outflow from earlier upstream
convection. That boundary is the main focus for convective chances
through tonight, combined with added forcing from a stronger upper
wave working east out of Wyoming at the moment and expected to lift
just to our west on Sunday. Plenty of heat and humidity in place
ahead of that cold front right now, with the current Heat Advisory
for western areas and Excessive Heat Warnings farther east working
out quite well. That heat/humidity is also contributing to 2500-
3500+ J/kg MLCAPE, though held back for the moment by lingering low
level inhibition per current satellite trends and forecast soundings.
Things should change roughly 20-21Z with persistent hints we`ll
erode the remaining cap. Overall shear honestly isn`t terribly
great, with recent RAP runs backing away even more from 0-3km shear,
only showing around 20-25 knots and limited deeper layer shear.
However, with modest mid level lapse rates, the noted degree of
instability, and impressive DCAPE profiles of 1500+ J/kg, still
think we`re in line to see at least a handful of stronger line
segments with a good wind threat. Despite overall storm motion to
the north/northeast, get the feeling that outflow will help
propagate storms farther east a bit quicker than earlier expected,
so will have to watch near-term trends as any "stalling" will
result in training convection and possible flooding concerns.
Do have some concerns for additional convection developing this
evening and tonight on the nose of a strong low level jet/moisture
transport signal pointed into northeast Iowa and southern
Minnesota ahead of the above-mentioned approaching upper wave.
Exactly where and how widespread additional convection becomes
remains in question, but have "upped" our messaging in that
fashion given PWAT values around 2 inches or better and warm cloud
depths pushing 4km or better (great heavy rain indicators). At
the moment, confidence honestly still not high enough to warrant
any time of Flash Flood Watch given the remaining uncertainties
about how widespread any flood threat would be, but will watch
trends this evening closely.
The upper wave should lift north of the area by Sunday afternoon,
swinging a cold front through the area. 12Z guidance looking just a
touch slower getting that boundary out of our eastern areas, so will
have to watch that we don`t end up with a sneaky stronger storm or
two given much more robust low and deep layer shear. That risk is
certainly much higher just east of our area into eastern Wisconsin,
with the bigger story being a return to notably cooler conditions
(though still quite a bit humid) with added clouds and occasional
showers.
.LONG TERM...(Sunday Night through Saturday)
Issued at 240 PM CDT Sat Jun 30 2018
Most of the rain should be out of the area by Sunday night, but
could see a few lingering showers in far eastern portions of the
forecast area. Otherwise, models remain in good agreement regarding
the general pattern through the work week with upper level ridging
working back into the area and various weak shortwave troughs
bringing precip chances. Unfortunately, very little model agreement
on timing and placement of these shortwaves, so confidence in
precipitation forecast for the work week is rather low, though given
weak nature of the shortwaves, not expecting any periods of
widespread rain. Looking at temperatures, we`ll be heating back up
as the ridging builds in. At this point, 925 mb temperatures look to
be the warmest on Wednesday (around 25-27 C), so could see highs
back into the 90s in many spots, pending clouds and precipitation.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 640 PM CDT Sat Jun 30 2018
Challenging aviation forecast with multiple lines of showers and
thunderstorms through at least midday Sunday. Don`t want to litter
the entire period with thunder chances, so multiple updates are
possible. Current focus is on line of thunderstorms just west of
KRST. Expect at least MVFR reductions as it moves through with
gusty west-northwest winds. This line should also impact KLSE by
01.01Z. Later into the evening, expect mostly showers, but some
additional thunderstorms are possible. Convective chances even
more uncertain into Sunday. Away from thunderstorms, winds will
generally be light with a southerly component, turning more to the
west-southwest late in the period.
&&
.HYDROLOGY...
Issued at 240 PM CDT Sat Jun 30 2018
Watching convective trends the next handful of hours with slower
storm motions anticipated as low level shear vectors support some
potential training of storms out ahead of a slow-moving cold
front. Confidence still not high enough to warrant a Flash Flood
Watch just yet, but can`t rule out some localized flash flooding
where/if any storms train over the same areas. The atmosphere is
quite juicy, and rainfall rates of 2-3 inches per hour or even
more are possible with any storms. Have maintained the ESF and web
graphics to highlight the rain potential and will watch near-term
trends closely into the evening.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
UPDATE...Rogers
SHORT TERM...Lawrence
LONG TERM...Lawrence
AVIATION...Rogers
HYDROLOGY...Lawrence
Area Forecast Discussion
National Weather Service Bismarck ND
944 PM CDT Sat Jun 30 2018
.UPDATE...
Issued at 944 PM CDT Sat Jun 30 2018
One lingering shower/thunderstorm northwest, otherwise convection
has dissipated across western and central ND this evening. Will
remove thunder wording from the HWO and state forecast product.
No other updates needed for this forecast issuance.
UPDATE
Issued at 632 PM CDT Sat Jun 30 2018
Will continue with low chances for showers and thunderstorms this
evening. Shear is weak and mid level lapse rates are low so do not
expect any strong storms this evening. Convection will slowly
move east over the next few hours before diminishing altogether
before midnight as the atmosphere decouples.
ALl other forecast elements on track for tonight.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 300 PM CDT Sat Jun 30 2018
Highlights in the short term forecast include isolated showers and
weak thunderstorms through this evening, and a marginal risk of
strong to severe storms north central Sunday afternoon.
A broad middle and upper-level trough is present across the region
this afternoon, with one potent embedded shortwave centered across
WY and a weaker impulse moving across northeast MT per GOES-16
low-level moisture channel imagery. The northeast MT impulse will
likely aide isolated to perhaps scattered convective development
in western and central ND late this afternoon and evening. Based
on modifications to the 12 UTC Bismarck sounding and more recent
model-simulated profiles, steep low-level lapse rates are likely
contributing to MLCAPE on the order of 500 J/kg. However, midlevel
lapse rates are only around 6 C/km, which will likely tend to
limit overall updraft strength and altitude. Even so, deepening
cumulus fields are being observed as of mid afternoon, especially
in closer proximity to the upstream weak shortwave impulse, and
the CAMs through the 17 UTC HRRR continue to simulate isolated to
scattered convection through the early evening, so we will keep a
mention in the forecast, generally along and west of Highway 83.
We expect any activity to diminish by late evening as the lower
atmosphere cools and boundary-layer-based instability concurrently
diminishes.
On Sunday, the 12 UTC global model guidance consensus calls for a
stronger shortwave trough moving into the broad 500 mb trough with
the primary region of differential cyclonic vorticity advection in
the U.S./Canadian border region. The associated cooling aloft will
likely help steepen midlevel lapse rates in support of MLCAPE from
500 to 1000 J/kg given dewpoints in the 50s F near an associated
surface low and weak cold front, mainly in far north central ND.
Only modest increases in midlevel winds are forecast ahead of the
shortwave trough, yielding 0-6-km bulk wind differences averaging
30 kt in support of primarily a multicell convective mode. Given
the expected CAPE-shear setting, there is some risk of strong to
marginally severe storms in far north central ND, though timing of
the midlevel shortwave trough and associated surface front will be
crucial to the western bound of that risk. Both the 12 UTC NAM and
09 UTC SREF calibrated severe thunderstorm probabilities suggest
the greatest risk may focused further east in northeastern ND.
Otherwise, a well-mixed boundary layer is forecast along and west
of the Highway 83 corridor Sunday afternoon in the wake of the
surface front and in a region of at least modest low- and midlevel
subsidence, all of which could favor momentum transfer in support
of breezy west winds. We therefore relied on the higher edge of
wind-speed guidance from the 12 UTC model output for the forecast
on Sunday afternoon.
.LONG TERM...(Sunday night through Saturday)
Issued at 300 PM CDT Sat Jun 30 2018
The long term forecast will be characterized by a chance of storms
from Monday night through Independence Day, and then the arrival
of hotter and more humid weather by next weekend.
A strong subtropical ridge is expected to retrograde westward from
the eastern seaboard early this week to the central U.S. by Friday
per the 00 and 12 UTC global model suite. Initially, the northern
Plains will be in southwest flow aloft with a quasi-stationary
frontal boundary from western SD into eastern ND per the 12 UTC
GFS and ECMWF, resulting in a chance of thunderstorms as a series
of impulses cross the region. At least one stronger shortwave is
likely to cross the region in the time period centered on Tuesday
night, but in general predictability of the impulses aloft is low,
and model simulations suggest that the frontal zone -- and the
warm sector to its south and east -- may tend to be capped to deep
convection much of the period. That could tend to favor post-
frontal convection evolving from the high terrain of MT/WY during
the afternoon hours each day and reaching the area nocturnally.
Given strong wind fields aloft and the close proximity of rich
low-level moisture near the frontal zone, there will be some risk
of strong to severe storms in this period, even in the post-
frontal regime, but confidence in the potential is modest at best.
Note too that convective-parameterizing model output does indeed
simulate significant warm-sector development near the surface
front in south central and especially southeast ND both Monday
and Tuesday afternoon and evening, but based on forecast 500 mb
height tendencies and evaluation of simulated warmth at the base
of an elevated mixed layer, that may be significantly overdone. As
a result, our QPF-blend-driven PoP forecast may be too aggressive
in close proximity to the front during the afternoon and evening
both days.
Otherwise, once heights aloft begin rising more substantially by
late this week and next weekend, convective opportunities may
trend downward overall, while highs will likely increase close to
90 F by Friday and Saturday per the multi-model consensus.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 944 PM CDT Sat Jun 30 2018
Clouds diminishing this evening along with the chances for
showers. Next chance for showers and storms will be Sunday morning
northwest and Sunday afternoon north central. Overall VFR
conditions should be expected.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...CJS
LONG TERM...CJS
AVIATION...NH
Area Forecast Discussion
National Weather Service Columbia SC
1026 PM EDT Sat Jun 30 2018
.SYNOPSIS...
Lingering surface troughing and strong heating will help
support scattered mainly afternoon and evening thunderstorms.
Typical summertime weather can be expected next week as weak
high pressure resides over the region.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Weak upper level low over Mississippi with ridge over eastern
North Carolina. Surface trough over central Ga extending into
the CSRA early this evening. Persistent light east-southeast
flow overnight should result in high low-level moisture. Muggy
conditions with dew points in the mid 70s in some areas. HRRR and
Lamp suggest some patchy stratus possible toward daybreak.
Radar and satellite trends indicate showers diminishing across
the area with loss of heating. Low tonight will be in the low to
mid 70s.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/...
Center of upper ridge will remain off to the north and northeast
of the area through Tuesday night, with a weak trough well west
of the area. Onshore flow pattern will continue to bring
moisture inland, and with it scattered afternoon/early evening
showers and thunderstorms each day. Best rain chances may remain
across western counties due to them being slightly further away
from the upper ridge. Afternoon highs remain seasonably warm
each days with readings in the low to mid 90s. Overnight lows
fall between 70 and 75 degrees.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As we get into the longer term, models indicating a weak area of
low pressure moving westward in the easterly flow. A the same
time, the upper ridge north of the area strengthens and pushes
westward. This will bring enhanced easterly flow to the area,
along with continued moisture from the Atlantic. Depending on
the strength of the upper ridge, the westward moving low should
remain south of the forecast area, pushing into portions of GA
Wednesday/Wednesday Night. Weak ridging takes hold for Thursday,
then another westerly moving low being shown by long range
models for next weekend. With all the moisture, expecting
mainly diurnal showers and thunderstorms each day. Daytime high
temperatures will be in the low to mid 90s with nighttime lows
in the low 70s.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
VFR conditions for the majority of the period with restrictions
possible in late afternoon and evening thunderstorms and early
morning fog or stratus.
Fog and stratus will be possible around daybreak with abundant
low-level moisture present. Model guidance has been trending
more optimistic with only patchy fog and a few areas of stratus
early Sunday morning. With similar conditions to the previous
night fog may be most likely at AGS around sunrise. Although we
cannot rule out brief periods of fog or stratus at any site.
Winds overnight will be light and variable with the moist
easterly flow returning by late morning. In the afternoon and
early evening, winds will be out of the SE from 5 to 10 kts
with scattered thunderstorms developing.
EXTENDED AVIATION OUTLOOK...Restrictions possible each day in
early morning fog/stratus and mainly afternoon and evening
thunderstorms.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
322 PM MDT Sat Jun 30 2018
.SYNOPSIS...
A disturbance aloft, along with unstable air, will help kick off a
few thunderstorms this evening over Otero and Hudspeth Counties.
The disturbance aloft will move off to the northeast Sunday,
bringing in mostly sunny skies, though some residual moisture
persisting will give the Sacramento Mountains a slight risk of a
thunderstorm. Southerly flow aloft will increase Monday and
Tuesday, bringing some tropical moisture back up to the Borderland
and a risk of isolated thunderstorms for most of the area.
&&
.DISCUSSION...
Summertime "hit or miss" thunderstorm pattern looks like it will
continue through much of the forecast period. Currently vort
center aloft hard to find in satellite imagery but likely over
northern Otero County, helping kick off a few thunderstorms over
that area. Some orographic thunderstorms have developed over the
Black Range, but don`t expect that area to remain active tonight.
Strong dry slotting taking place behind the exiting vort center,
but fairly dense convection still occurring over the Sierra
Madres. Believe that is only orographically aided and not the
result of another short wave moving up. HRRR does show
considerable convection over northern Mexico next few hours
drifting east but mostly dissipating before reaching west Texas.
Will keep low POPs in this evening for eastern Otero and Hudspeth
Counties.
With vort center lifting out of area to the northeast, northern
Gulf of Mexico high center aloft will begin building back to the
north and west. This will briefly dry us out on Sunday, but then
begin streaming some tropical moisture back up over the area
Monday into much of next week. Models not quite as bullish on QPF
as previous runs, so somewhat lower POPs look reasonable; having
said that POPs still remain for all zones. Inverted trough
developing over far east Texas continues to be less and less a
player, still moving through the Big Bend Thursday, but hardly
affecting the CWA. Feature still drags a back door front into the
area Thursday night, but becoming less pronounced, with only minor
cooling for Friday. The upper high migrates north over
Nebraska/eastern Wyoming by Thursday into the weekend, maintaining
persistent east flow aloft. While not a bad flow for our precip
chances, the trajectory is mostly from over the SE U.S. states and
not the Gulf of Mexico, so don`t expect any widespread showery
days--just hit or miss each day.
&&
.AVIATION...Valid 01/00Z-02/00Z.
VFR conditions for most areas through the period. Drier westerly
winds are pushing moisture to the east. Fewer clouds Sat night
through Sunday and less storm development mainly isolated north of a
TCS-Orogrande line. Skies: FEW070 SCT150. VSBY P6SM. Winds W to NW 7-
15kts...gusts to 22kts. In VCTY of TSTMs local CIGs BKN040...VSBY 2-
3SM...Winds VRBL 25G35kts.
&&
.FIRE WEATHER...
An upper trough moving through the Central Rockies today will bring
warmer and drier westerly flow over the area through the weekend.
Expect warmer temperatures and lower relative humidity today and
again Sunday as Min RH levels drop to less than 15% in the lowlands
and Gila Wilderness and 20% in the Sacramentos. Rain and storm
chances will be much reduced...especially over the western areas. By
Monday into next week, moisture begins to move back in from the
east. Thus rain and storms chances will again increase from east to
west across southern New Mexico through the week and this will up
the chances for new lightning starts out west early-week storms will
likely be more dry than wet.
&&
.PRELIMINARY POINT TEMPS/POPS...
El Paso 73 99 72 100 / 0 0 0 10
Sierra Blanca 68 98 68 96 / 10 0 10 20
Las Cruces 65 98 66 98 / 0 0 0 0
Alamogordo 65 98 67 97 / 10 0 0 30
Cloudcroft 49 74 51 74 / 10 30 10 50
Truth or Consequences 68 99 67 98 / 0 0 0 10
Silver City 59 91 60 93 / 0 0 0 0
Deming 62 99 63 99 / 0 0 0 0
Lordsburg 62 95 63 98 / 0 0 0 0
West El Paso Metro 71 98 71 99 / 0 0 0 10
Dell City 66 97 67 100 / 10 10 10 20
Fort Hancock 67 100 70 100 / 10 0 0 20
Loma Linda 66 96 65 95 / 10 0 0 20
Fabens 66 99 68 100 / 0 0 0 10
Santa Teresa 67 98 68 99 / 0 0 0 10
White Sands HQ 68 98 69 97 / 0 0 0 20
Jornada Range 62 100 66 99 / 0 0 0 10
Hatch 62 101 65 100 / 0 0 0 0
Columbus 66 100 66 100 / 0 0 0 0
Orogrande 69 99 69 98 / 10 0 0 20
Mayhill 54 82 55 83 / 10 30 10 40
Mescalero 53 84 55 84 / 10 30 10 50
Timberon 52 83 54 82 / 10 30 0 40
Winston 52 94 55 92 / 0 0 0 10
Hillsboro 61 97 61 97 / 0 0 0 10
Spaceport 63 99 66 99 / 0 0 0 10
Lake Roberts 47 93 50 92 / 0 0 0 10
Hurley 58 93 59 95 / 0 0 0 0
Cliff 59 97 59 97 / 0 0 0 0
Mule Creek 58 95 59 98 / 0 0 0 0
Faywood 60 95 61 96 / 0 0 0 0
Animas 63 96 63 99 / 0 0 0 0
Hachita 61 98 62 98 / 0 0 0 0
Antelope Wells 62 96 63 98 / 0 0 0 0
Cloverdale 60 93 60 95 / 0 0 0 0
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
NM...None.
TX...None.
&&
$$
Hefner/Novlan
Area Forecast Discussion
National Weather Service Green Bay WI
1045 PM CDT Sat Jun 30 2018
Updated aviation portion for 06Z TAF issuance
.UPDATE...
Issued at 556 PM CDT Sat Jun 30 2018
After a marked increase in intensity in the 20Z-22Z time frame,
storms seem to have somewhat leveled off. The overall trend on
the models has been to forecast the initial storms to weaken
somewhat as they head east and away from the cold front. That
seems to be what has happened thus far, but local meso-plots
indicate low-level moisture convergence is now increasing so will
need to watch and see if the weakening trend holds.
Otherwise, plan to let the heat-related headlines expire as
scheduled at 00Z.
If the storms the rest of the night do not adequately overturn the
airmass in eastern Wisconsin, the potential will exist for severe
weather there tomorrow. Wind fields and large-scale forcing will
be stronger at that time, which may offset weaker instability.
&&
.SYNOPSIS...
Issued at 239 PM CDT Sat Jun 30 2018
Periods of thunderstorms tonight and Sunday. Though the worst of
the hot and humid conditions occurred today, very warm and rather
humid weather is likely to continue through at least the middle of
next week.
The forecast period begins with a seasonably strong band of
westerlies across the northern CONUS and southern Canada, with
ridges off the West Coast and in the Great Lakes region, and a
trough over the Rockies. The trough will broaden some as energy
shears out to the northeast the next couple days. A substantial
retrogression of the entire pattern is forecast during the
middle to latter part of next week, with the trough reamplifying
off the West Coast, and the ridges shifting back toward the
Aleutians and western Plains. That will allow troughing to develop
over eastern Canada and New England next weekend.
Although the heat and humidities as extreme as today are not
anticipated again during the period, the pattern favors very warm
and rather humid conditions continuing through at least the
middle of next week. The upper flow tilting northwest as the upper
ridge shifts back into the Plains may eventually allow for some
slightly cooler and less humid conditions late in the period.
Given the available moisture, there appears to be enough
opportunities for precipitation to result in AOA amounts for the
period.
&&
.SHORT TERM...Tonight and Sunday
Issued at 239 PM CDT Sat Jun 30 2018
The latest RAP analysis and satellite/radar imagery show a cold
front stretching from southeast Minnesota to western Wisconsin
early this afternoon. Although the most potent storms have
occurred over the Upper Peninsula so far today, cu is getting more
agitated along the front and into north-central Wisconsin where
temps have reached their convective temp. ML capes are very robust
in this area this afternoon, in the 2600-3600 j/kg. The hourly
models continue to show convection ramping up in the 20-22z time
period in this corridor. Although the strongest wind fields are
behind the front, 25-30 kts of deep layer shear remain supportive
of scattered severe storms given the beefy instability present.
Apparent temps also remain on track to reach excessive heat
warning criteria at several locations over central and northeast
WI. But the focus of this forecast is on severe thunderstorm
chances.
Tonight...The cold front will not make much headway to the east
tonight as it waits for a deeper trough that will be moving across
the Plains. However, many of the higher resolution models show the
thunderstorms racing eastward across the area this evening,
probably propagating on their outflow. Severe weather chances will
quickly diminish during the evening as the storms outrun the
front, and nocturnal stability increases. However, severe weather
chances will likely continue through mid-evening, and most
concerned with central and north-central WI where instability and
shear will be most supportive. Damaging winds, large hail, and
localized flooding will be the main threats from the storms. Most
thunderstorm activity should diminish by early overnight, leaving
spotty showers and storms, and some low clouds hanging back around
the front over western sections of the forecast area. Temps will
remain warm and humid, but not quite as warm as last night due to
the possibility of rainfall.
Sunday...As a shortwave quickly moves northeast across the
northern Mississippi Valley, surface low pressure will track along
the front and across northwest Wisconsin in the morning and
western Lake Superior in the afternoon. Depending upon how
thunderstorms and resultant cloud cover evolve tonight may impact
how heating occurs tomorrow. If sufficient heating can occur, ML
capes of 1500-2500 j/kg appear possible across eastern WI during
the afternoon. With passage of the cold front and strengthening
wind fields aloft (30-40 kts), severe thunderstorms appear
possible again, this time primarily over eastern WI. Damaging
winds and large hail will be the main threats. Temps will fall
back into the upper 70s to mid 80s. With the humidity, a few
locations will see heat indices reach the mid 90s.
.LONG TERM...Sunday Night Through Saturday
Issued at 239 PM CDT Sat Jun 30 2018
The cool front will settle south of the area Sunday night and
begin to dissipate. It does not appear there will be much of a
push of cooler and drier air behind the front, but mixing into
drier air aloft will probably knock dew points back primarily into
the 60s for Monday and Tuesday. Building upper heights as the
eastern North American ridge begins it`s westward shift will also
be unfavorable for precipitation. Although it may not be possible
to totally rule out precip, any convection during this period
is likely to remain isolated with most areas staying dry.
The tail of a shortwave embedded within the main westerlies will
brush the area Wednesday/Wednesday evening (Independence Day).
That will result in a chance of showers and storms, especially
across the north. Slightly cooler and less humid air is likely to
settle into the area as the upper flow turns northwest late in the
period, though temperatures will probably remain at least somewhat
above normal into next weekend.
Overall, the standard extended forecast initialization grids based
on a broad blend of guidance products seemed to adequately, so few
adjustments were necessary.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1036 PM CDT Sat Jun 30 2018
Primarily VFR conditions are expected across the area during the
next 24 hours. The main concern overnight will be the potential
for fog for any areas that clear out overnight, particularly
across the north where the heaviest rain fell. However, satellite
observations show there isn`t much in the way of clearing
upstream, therefore will leave out of the TAFs. Additional
thunderstorms are possible across the area Sunday afternoon as a
cold front moves through the area. Some of these storms could have
strong winds and hail with brief lower ceilings and visibilities.
Will continue to carry a PROB30 group for this possibility in the
TAFs given the low confidence in storms actually hitting each TAF
site.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement until 1 AM CDT Sunday for WIZ022-040-050.
&&
$$
UPDATE.........Skowronski
SYNOPSIS.......Skowronski
SHORT TERM.....MPC
LONG TERM......Skowronski
AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
835 PM CDT Sat Jun 30 2018
.UPDATE...
834 PM CDT
No major changes to the forecast this evening. Explosive
convection across far NW Illinois may still clip the far NW CWA
late this evening, but lingering capping away from appreciable
mid-level forcing and a developing LLJ over Iowa should prevent
the convection from making it much farther east. The outflow from
this convection may reach the Chicago metro while washing out
during the early overnight hours. Otherwise, the forecast looks on
track with regard to temps and the continuing Excessive Heat
Warning through Sunday across much of the CWA.
Kluber
&&
.SHORT TERM...
300 PM CDT
Tonight through Monday...
Heat continues to be the immediate focus of the forecast this
afternoon, with thunderstorm potential gradually increasing later
tonight and more so on Sunday. Some locations, particularly the
southeast parts of the cwa, will likely see nearly similar heat
conditions Sunday before thunderstorm coverage increases later in
the afternoon, and thus have elected to extend the Excessive Heat
Warning through 7 pm Sunday, roughly east of the I-39 corridor.
Afternoon water vapor imagery indicates the upper ridge has
shifted east across the eastern Midwest and mid-Atlantic region.
The low level thermal ridge axis remains back across the
Mississippi Valley however, with another hot and very humid
afternoon underway across the forecast area. Temps in the 90-95
range, and heat indices ranging generally from 105-115F
characterize the air mass across the cwa at 2 pm. Farther west, a
cold front trails from surface low pressure over Manitoba,
southward across northwest Iowa and into the Central Plains.
Thunderstorms had developed across northern Iowa in the low level
convergent axis ahead of the front, in response to a northeastward
propagating short wave downstream of a broad upper trough. This
trough, and surface cold front, will move slowly east into the
local area Sunday, with a gradual increase in thunderstorm
potential beginning later tonight.
Moderate to strongly unstable conditions were in place across the
forecast area this afternoon, thanks to the hot/humid air mass
across the region. RAP analysis depicts MLCAPE values of 3500-4500
J/kg, with minimal capping noted in forecast soundings. Little
low level convergent focus is noted however, with GOES-16 high res
1-minute visible imagery showing a broadly anti-cyclonic cu
field. Can`t rule out an isolated shower or storm especially
across the southwest/western cwa late this afternoon where capping
is weakest, though coverage, if any storms actually occur, is
expected to be quite low. High-res CAM guidance has backed off in
developing any storms here this afternoon, from a few runs earlier
this morning which did. Guidance is in somewhat decent agreement
in spreading current Iowa convection eastward into parts of WI,
northwest and possibly north central IL very late this evening,
though generally in a weakening mode forced by outflow. Convective
models then keep things pretty quiet across the area until Sunday
afternoon, when our pre-frontal air mass again diurnally
destabilizes. Looks to be a fairly high probability of storms
ahead of the cold front Sunday afternoon. Strong instability, and
stronger southwesterly wind field aloft will likely support the
threat of strong/severe storms, with damaging winds being the
primary threat. Locally heavy rainfall will also be a concern,
with PW`s approaching 2.00 inches. Individual storm motion should
be fairly progressive, though any backbulding into the southwest
flow could produce training which could lead to localized
flooding, given potential for efficient rain production. Actual
cold front passes slowly Sunday night, so thunderstorm potential
will linger across the east into the night. Have a lingering
chance across the far southeast Monday, as front slows up even
more north of the Ohio River.
Pre-frontal air mass looks to be only marginally "cooler" than
today or Friday, especially across the east and south parts of the
area least likely to be affected by decaying overnight convection
or outflow. While raw numbers may be short of warning criteria,
have elected to extend the Excessive Heat Warning through 7 pm
Sunday for all but north central IL. Confidence is somewhat
limited, given the potential for increased cloud cover, convective
outflow, etc., but did not want to "ramp down" to an advisory
especially cumulative effects of heat and another day of 100-105+
heat indices. Storms should push the last of the real heat out
Sunday night, which should allow headlines to expire by early
evening. High pressure develops across and north of the area
Monday, with "cooler" northeast flow keeping temps from the low-
mid 80s along the Lake Michigan shore, to the upper 80s inland.
Ratzer
&&
.LONG TERM...
325 PM CDT
Monday night through Saturday...
Some low chances for thunderstorms briefly early Monday evening
along the eastern side of the surface ridge. Should be a small
window though with the bulk of any development likely remaining
just outside of the area. Upper level ridging still expected to be
the main feature next week, with guidance indicating this will be
a continued feature through the remainder of the work week. In
this pattern, expect hot conditions to likely persist across the
region and in this pattern, could see higher dewpoints/humid air
to remain in place. Will need to continue to monitor high temps
and dewpoints, as higher heat indices are a concern mid/late in
the work week. Tough to really focus on any feature supportive of
higher precip chances during the period, however, could see this
pattern also providing periodic thunderstorm chances and have
continued this theme in the forecast. This is especially the case
Thursday night into Friday when a surface trough/boundary approach
the area from the north, supporting a more organized setup for
thunderstorm development.
Rodriguez
&&
.CLIMATE...
Record Temps
For the Chicago area...
Record High Max Temp
June 30: 99F (1913, 1953)
Record High Min Temp
June 30: 80F (1931)
For the Rockford area...
Record High Max Temp
June 30: 102F (1931)
Record High Min Temp
June 30: 74F (1913, 1931)
&&
.AVIATION...
For the 00Z TAFs...
Gusty south winds should gradually diminish this evening across the
area. Ongoing convection across NE Iowa may clip RFD to the north
mid to late evening. There is uncertainty how far SE the associated
convective outflow will reach into northern IL. Anticipation is that
outflow will dissipate around the Chicago metro during the early
overnight hours. Winds at ORD/MDW/DPA may become NW or VRB for an
hour or two between 06-09Z before settling back to S winds by
daybreak. Gusty S winds are then expected well into the afternoon at
all sites, with high-end MVFR BKN cumulus possible at times late
morning into the early afternoon.
Focus is then on the expected initiation of convection around 20Z
Sunday just east of the Mississippi River. The line of broken
convection should move eastward across northern IL and NW IN through
the early evening. Strong to severe storms are possible, with strong
wind gusts from microbursts being the main threat.
Kluber
&&
.MARINE...
341 PM CDT
Southerly winds in place this afternoon across much of the lake,
with this direction likely remaining tonight. Higher speeds in
place at this time with surface trough/low just to the northwest,
but do think a slight diminishing trend will be possible later
tonight. This would be brief though, as this pattern will support
another period of strengthening southerly winds on Sunday. Expect
increased winds over the open waters and nearshore waters, and
will need to monitor speeds over the nearshore as higher winds
hazardous for small craft will be possible for a time Sunday
afternoon into Sunday evening. Lower confidence at this time with
this possibility, but at least a small window of these higher
speeds are a definitely possibility.
Rodriguez
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Excessive Heat Warning...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011
until 10 PM Saturday.
Excessive Heat Warning...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-
ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-ILZ039
until 7 PM Sunday.
IN...Excessive Heat Warning...INZ001-INZ002-INZ010-INZ011-INZ019
until 7 PM Sunday.
LM...None.
&&
$$
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Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1105 PM CDT Sat Jun 30 2018
.SHORT TERM...(This evening through Sunday)
Issued at 219 PM CDT Sat Jun 30 2018
Surface analysis this afternoon shows a nearly-stalled cold front
extending SW from a low pressure center near Superior WI through
southeastern MN into north-central IA. A more subtle cold front is
shown from a low pressure center over southern Manitoba province
extending SW into far NW MN into SE ND. Aloft, solid southwest
flow prevails while a trough axis pushes off the Rockies and into
the northern-central Plains. A deep plume of moisture is pushing
PWATs into the 1.5-1.75 inch range with MLCAPEs hitting around
3000 j/kg with nearly no CINH. This combination of features, along
with plenty of insolation, has allowed convection to spark over
northern IA into SW-W MN this afternoon. CAMs continue to show a
merging of clusters over eastern MN into western WI through the
rest of this afternoon and evening. Bulk shear in the 40-30kt
range combined with steep mid-level lapse rates (around 7C/km)
still indicate the potential for all 3 severe storm modes although
the highlighted modes are large hail and damaging winds through
the early evening hours. With the front making little progress
eastward tonight into Sunday morning, the bulk of the
thunderstorms will occur over southern and eastern portions of the
WFO MPX coverage area. The other aspect which the CAMs have shown
is for there to be two distinct parts of this event over the next
18-24 hours: the current event which will continue through this
evening then a second rush of rain from the early morning hours
through daybreak. While the severe push looks to be during the
former, the heavy rain event looks to be the latter. The lack of
progression of the cold front combined with an increasing H85 jet
to around 30 kts would help produce training cells and fairly good
coverage of mod-hvy rain over southern MN into western WI.
Localized rainfall amounts of 2-4" cannot be ruled out through
tomorrow, especially over far southern MN where the flash flood
watch will be maintained. The rainfall is expected to steadily
wane and shift eastward tomorrow morning such that the bulk of the
area looks to be dry Sunday afternoon. As for temperatures, lows
tonight will be about 7-10 degrees cooler across the coverage area
compared to this morning followed by highs on Sunday that will
only climb to around 80 degrees.
.LONG TERM...(Sunday night through Saturday)
Issued at 219 PM CDT Sat Jun 30 2018
As the cold front at the surface continues to move east of the area
we return to more of a zonal flow pattern aloft into Tuesday. After
a brief dry spell Sunday evening into Monday afternoon, thunderstorm
chances return Monday evening across western & northwestern MN as
the LLJ ramps up. With little to no forcing aloft we`re not
expecting much in the way of heavy rain or severe weather with these
storms.
Upper-level ridging builds back to the west mid-week & with it comes
a return to hot & muggy weather. As the ridge builds our flow aloft
becomes southwesterly with a potent mid-summer trough passing off to
our north. The low at the surface over Manitoba will drag a weak
cold front over our area Wednesday into Thursday & bring with it
another chance for thunderstorms. Models are beginning to converge
on a solution bringing the best chance for thunderstorms into our
area Wednesday evening so unfortunately it looks like we may have
some wet weather to deal with for Independence Day celebrations.
As the cold front slides east Thursday, high pressure at the surface
builds over the Great Lakes & should keep us relatively dry into the
weekend. Expect warm & muggy weather into Thursday with highs in the
mid-upper 80s, with a return to more seasonable temperatures
beginning Friday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1105 PM CDT Sat Jun 30 2018
Writing is on the wall for a large shield of rain with embedded TS
to impact the MPX terminal tonight through Sunday morning. 00z
CAMs came pretty much in line with what the HRRR has been showing,
so brought prevailing precip in to all terminals, though may not
be fast enough with it. Besides the rain, MVFR cigs look likely as
well and went with a blend of the LAV and HRRR for those.
KMSP...No avoiding the rain, which looks to begin impacting MSP
between 7z and 10z and will last through most of Sunday morning.
Lower confidence on how low cigs will go, but approaching 1k feet
is certainly plausible Sunday morning.
/OUTLOOK FOR KMSP/
Mon...VFR. Wind SW 10-20 kts.
Tue...VFR. Wind SSE 10-20 kts.
Wed...Mainly VFR. Chance MVFR/TSRA late. Winds S 10-15 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&
$$
SHORT TERM...JPC
LONG TERM...ETA
AVIATION...MPG
Area Forecast Discussion
National Weather Service Omaha/Valley NE
909 PM CDT Sat Jun 30 2018
.UPDATE...
Issued at 902 PM CDT Sat Jun 30 2018
Have allowed Severe Thunderstorm Watch 245 to expire at 9 PM for
much of eastern Nebraska and all of southwest Iowa. However there
remains a small threat for hail or a severe wind gust in southeast
Nebraska for an hour or so where storms track northeast from
northeast Kansas.
While heaviest rains have ended across our area, moderate rainfall
was persisting in Flash Flood Watch area. Radar estimates of 1.5
to 2 inch amounts have only heightened flood threat for overnight
storms. That area was racing into central Nebraska at late
evening, and meso-scale models maintain storms across eastern
Nebraska and western Iowa beginning before midnight. One positive
note is that area of storms will be progressive, so localized
intense rainfall is not anticipated. Still, another half inch to
an inch could fall on areas that already received plenty of rain
this evening. Thus flash flood watch will continue.
&&
.SHORT TERM...(Tonight through Tuesday)
Issued at 320 PM CDT Sat Jun 30 2018
Thunderstorms and heavy rain threat remain the primary forecast
concerns.
Aside from a lone thunderstorms that tracked northeast of our area
this morning, convection has been slow to initiate at mid afternoon.
Cold front has slipped into the Omaha Metro area as of 230 PM, and
extends to the northeast near Denison Iowa, and to the southwest
south of Lincoln. Airmass near and south of the front is unstable as
latest RAP analysis suggests MLCAPE near 3500 J/kg. However
extensive cloud cover limiting surface heating has kept low level
lapse rates contained. Mid level cooler air was slow to arrive as
well, and mid level lapse rates were struggling, too. Looks like
we`ll have to wait for mid level impulse currently in north central
Kansas to move closer for further erosion of cap for storm
initiation. When convection does fire, damaging winds and possibly
hail are likely give high instability and effective shear near 40kt.
There is still some tornado risk as well where storms can ingest low
level energy/helicity near frontal zone.
Trends in short-range meso-scale model output, while delaying
initiation, continue to develop storms this afternoon, with a
secondary surge during the evening originating from current
convection in south central Nebraska. Areas along and south of
Interstate 80 still appear under severe threat until sunset.
Then attention turns to stronger mid level trough rotating across
northern Nebraska overnight, and attendant thunderstorms and heavy
rain potential. There is at least a small risk for severe hail with
these as mid level temps are cooler. Precipitable water values
remain in the 1.5-2 inch range after 06Z, suggesting heavy rain is a
threat with all storms overnight. However the overnight system is
more progressive than evening convection along/south of front, so
additional rainfall may not be as copious. Still average rainfall of
of 1 to 2 inches is certainly possible with through Sunday morning,
with localized areas much higher if training along front occurs as
expected. Thus will continue Flash Flood Watch as is.
Beyond tonight, cooler air spilling in behind mid level trough
should keep highs in the 80s on Sunday. Return flow begins Monday
and continues into Tuesday, helping warm temperatures back into the
90s. There is a small chance for elevated convection Monday night as
low level jet noses into northeast Nebraska.
.LONG TERM...(Tuesday night through Saturday)
Issued at 320 PM CDT Sat Jun 30 2018
The main weather story for the rest of the week still looks to be
warmer temperatures as mid level heights rise with expanding ridge
from the Southeast into the Plains. Have highs in the 90s at least
through Thursday. GFS has been relatively persistent in indicating a
weakness in the ridge allowing convection to fire Thursday night
into Friday, and ECMWF is beginning to show some agreement. Thus
will continue with a chance for thunderstorms then, which in turn
will cut highs Friday and Saturday a few degrees.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 643 PM CDT Sat Jun 30 2018
Scattered thunderstorms will affect KOMA and KLNK during the 00Z
to 06Z period storms slowly drift north and east across the
region. Then another band of storms is forecast between 06Z and
12Z, moving in from the west. Attendant MVFR/IFR cigs/vsbys will
accompany any storms, with wind gusts over 40kt in some areas. A
band of MVFR cigs is expected to settle south across all TAF sites
after overnight storms move past, and will likely linger from 10Z
through 18Z before scattering out.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Flash Flood Watch until 7 AM CDT Sunday for NEZ015-033-034-044-
045-051>053-066>068.
IA...Flash Flood Watch until 7 AM CDT Sunday for IAZ043-055-056-069-
079-080-090.
&&
$$
UPDATE...Dergan
SHORT TERM...Dergan
LONG TERM...Dergan
AVIATION...Dergan
Area Forecast Discussion
National Weather Service Blacksburg VA
847 PM EDT Sat Jun 30 2018
.SYNOPSIS...
Ridging aloft will shift slowly east from the Appalachians
tonight to the middle Atlantic Coast by Sunday, where it will
then remain for much of the upcoming week. This will allow for a
slight increase in moisture on the west side of this ridge into
western parts of the Appalachians, and also for temperatures
and humidity to slowly increase through early next week.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 842 PM EDT Saturday...
Isolated convection has again formed near the northwest NC foothills
this evening associated with weak southeast flow within an axis
of residual stronger instability/moisture convergence to the
north of a stretched out vort lobe. These steering west around
high pressure to the north and may reach parts of the
mountains/foothills espcly from Watauga east across Wilkes into
Yadkin counties in the next hour or two before likely fading
with loss of heating. This in line with the latest HRRR which
actually has added shallow convection meandering off residual
outflow until around midnight across the far southwest. However
uncertain about how far north any of the showers will make it,
but still enough instability around to not count out isolated
coverage developing along a corridor from Independence to
Fries/Galax and Stuart in the next couple of hours per less cap
aloft off the 00z GSO raob. Otherwise after low pops southwest,
keeping things mainly clear under passing high clouds overnight
with some dense fog around in spots. Lows again not too bad
given dewpoints mainly in the 60s which should allow temps to
fall off to at or below guidance with only the southeast staying
around 70 for the most part.
Previous discussion as of 315 PM EDT Saturday...
Strong high pressure remains centered over the central
Appalachians with dry air aloft and a bit of a mid level
capping inversion, and thus overall lower than normal
precipitable water values. This airmass and profile aloft is
acting to keep any developing convection suppressed so far this
afternoon with a relatively shallow cumulus field seen in
visible satellite imagery. Some clustering can be seen in a few
locations over the higher elevations of NW NC and far SW VA as
well as to the south of the RNK CWA in central NC, with an
isolated shower see on radars to the south. There is still a
small chance that an isolated shower or weak thunderstorm could
develop across our far southwest this afternoon and this threat
could linger well into the evening as shallow southeast flow,
and thus uplsope component, increases somewhat this evening.
Kept precip chances at 20 percent or lower however and confined
to the NW NC mountains and foothills through late this evening.
Otherwise expect patchy valley fog to develop after midnight once
again in favored river valleys, especially New River and
Greenbrier, as we have seen last few nights.
For Sunday as the center of the upper ridge shifts east toward
the Atlantic coast and southeast flow deepens there will be a
slow increase in moisture especially at mid levels, but still a
good deal of mid level subsidence under ridge. Model consensus
is for slightly better chances and coverage of showers and
storms across NW NC and extending northward across far SW vA and
into SE WV. Best chances will be generally west of I-77 but
still think coverage will be scattered so not going any higher
than mid chance PoPs. With the slightly better upslope cannot
rule out an isolated shower or storm forming a little farther
north along Blue Ridge, probably no farther north than Roanoke
area. Guidance suggest a couple degrees warmer Sunday than today
but still likely well shy of records. See Climate section below
for what the record highs over the next few days though as we
may get close early next week in a couple spots.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 300 PM EDT Friday..
The dominate weather feature during the short term period of the
forecast will be an expanding upper level ridge, that is projected
to be 1-3 standard deviations above average per the 12z GEFS. This,
combined with increasing moisture from a weak low level southeast
flow, somewhat influenced by a westward moving low off the southeast
U.S. coast, will lead to heat index values from 100-105 from ROA to
east of the Blue Ridge.
The warmest day appears to be Tuesday when subsidence is strongest
as the upper ridge moves overhead, but Monday will only be a degree
or so behind. Leaned toward the warmer guidance values for highs
during this period.
Record highs for Monday and Tuesday (see climate section)are a
couple of degrees warmer than current forecast with the exception of
BLF, where the current forecast highs are forecast to match or
exceed records.
As for precipitation chances, expect scattered storms to develop on
the west edge of the building upper ridge as PWAT values increase, a
weak upslope southeast flow forms, and where mid level cap is
weaker. Highest pops will be from southeast WV through far SW VA
into NW NC. Precipitation coverage should be less on Tuesday, but
can`t rule out widely scattered storms developing along the eastern
slopes of the southern Blue Ridge.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 300 PM EDT Friday
The long-range models continue to be in good agreement shifting an
anomalously strong upper level west during the long term period.
With 850mb temps down just a touch Wednesday and Thursday compared
to Tuesday, highs may be a couple of degrees cooler. Still, heat
index values east of the Blue Ridge will reach between 95-100
degrees through Friday. There still is disagreement in the models
about the strength of a shortwave trof entering the northeast U.S.
on Friday, but the ECMWF has trended toward the more amplified GFS.
This should allow a cold front to approach and increase chances of
showers and storms Friday into Saturday. Due to the differences in
the model forecasts, there is low confidence on whether the front
will completely move through our forecast area, or will it stall on
Saturday. For now, kept highest POPs in the southern portion of our
forecast area on Saturday.
Prior to this front, a weak southeast flow off the Atlantic bring a
moist, but weak upslope flow, should be enough to spawn daily
afternoon and evening thunderstorms, especially across the southern
Blue Ridge.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
As of 645 PM EDT Saturday...
Overall VFR conditions will prevail into this evening with only
isolated showers possible well southwest of the TAF sites
through about midnight. Otherwise high pressure over the region
will again result in light winds and favorable radiational
cooling overnight. Fog will form again in the typical mountain
river valleys after midnight. The fog and/or stratus should mainly
impact KLWB with IFR to LIFR fog through 13Z/9AM Sunday, but
brief IFR visibility will also be possible at KBCB and KLYH.
Isolated to scattered thunderstorms should form again Sunday
afternoon mainly over the NW NC mountains but a few could sneak
farther north toward SE West VA including KBLF. Coverage and
confidence remains low at this point that they will move into
KBLF later Sunday as too isolated to include as well. Otherwise
TAF sites should remain dry with VFR conditions under scattered
cumulus during the day Sunday.
Forecast confidence is above average.
Outlook: VFR conditions will be the primary flight category through
mid-week, though with late night-early morning fog, and a slight
chance of an afternoon thunderstorm from Monday onward,
especially in the mountains.
Confidence in the above forecast is high, though predictability
of the afternoon storms is low for any given site.
&&
.CLIMATE...
Sunday 07/01/2018
Site MaxT Year
KBLF 90 2012
KDAN 100 2012
KLYH 98 1970
KROA 100 1931
KRNK 92 1959
Monday 07/02/2018
Site MaxT Year
KBLF 87 2011
KDAN 100 1954
KLYH 99 1898
KROA 100 1954
KRNK 95 1954
Tuesday 07/03/2018
Site MaxT Year
KBLF 89 2012
KDAN 99 1968
KLYH 97 2012
KROA 97 2012
KRNK 95 1954
&&
.EQUIPMENT...
As of 700 AM EDT Saturday...
The NOAA weather radio transmitter in Hinton, West Virginia
that is WXM72 and broadcasting at a frequency of 162.425 MHz
remains off the air, and will likely remain so through the
weekend and into early next week. Parts are on order to repair
the transmitter, but there is no known time of restoration. We
apologize for any inconvenience.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...SK
NEAR TERM...JH/SK
SHORT TERM...PH
LONG TERM...PH
AVIATION...JH/SK
CLIMATE...SK
EQUIPMENT...WERT
Area Forecast Discussion
National Weather Service Topeka KS
315 PM CDT Sat Jun 30 2018
.SHORT TERM...(This evening through Sunday)
Issued at 308 PM CDT Sat Jun 30 2018
Strong to severe thunderstorms with heavy rain and strong winds
are possible this afternoon and tonight, with a brief respite from
the heat on Sunday.
The early afternoon synoptic analysis featured a broad
subtropical ridge stretching from the Mid-Mississippi River valley
to the Mid-Atlantic region. A sharp northern stream H300
meridional trough axis was shifting eastward over Montana and
Wyoming--with some hints of an embedded closed upper low over
central Wyoming on GOES-16 water vapor imagery. A 60-70 kt jet
streak and H500 shortwave were rounding the base of this trough
and lifting northeastward towards the Northern Plains. Upper
tropospheric undulations/gravity waves were also noted this
morning emanating southward from the location of overnight
convection in Nebraska, with a low to mid tropospheric outflow
boundary noted on satellite, radar, and even for a short time in
the Salina to Manhattan observation network, where winds veered to
the north/west behind the passing boundary for a few hours this
morning before the mean southerly flow became reestablished. A
small MCV--remnants from earlier convection in Oklahoma, was
lifting northward through central Kansas. The region of DCVA ahead
of the low was helping generate isolated showers along the
aforementioned outflow boundary.
At the surface, a 1005 mb lee cyclone had gradually shifted off
the Front Range and into far western Kansas early this afternoon,
with an attendant frontal boundary arcing northeastward into SE
Nebraska and NW Iowa. This quasi-stationary boundary is forecast
to meander near the Kansas/Nebraska border through the rest of the
day, with isentropic upglide over the boundary serving as the
foci for thunderstorm development through the remainder of the
afternoon/evening. Several HREF members and the HRRR have been
hinting at the development of prefrontal showers and storms late
this afternoon in the warm sector from north central Oklahoma to
central Kansas. Have maintained slight chance to chance POPs to
account for these solutions. However, the threat for more
widespread showers and storms will come as the boundary sags
southward overnight between 04 and 10Z. Have pushed the heaviest
QPF to between 06 and 12Z timeframe in the forecast.
The overall convective environment in northeast Kansas features a
typical summertime setup--rich in buoyancy but lacking in deep
shear. MLCAPE values of 3000-4000 J/kg were noted on recent SPC
Mesoanalysis plots over the region, but with effective shear
values of only 15 to 25 kts. Given the minimal inhibition, even
weak lift associated with either the aforementioned outflow, MCV,
or H500 wave could lead to convective initiation. For now, have
focused afternoon POPs on the outflow and MCV, which already have
a history of producing convection. Storm mode is also complicated
by the lack of deep shear, hodograph inflection points, and weak
inhibition. Multi-cell clusters/lines are most likely given this
environment. Cold pools will be efficiently generated in this
regime with 1500-1700 J/kg of DCAPE and 0-3 km theta-e differences
of 25-35 C. Heavy rain will also be a threat with any training or
slow moving complex with PWATs of 1.5 to 2 inches approaching the
90-99th percentile of the climatological average. The hail and
tornado threat are non-zero given the possibility of isolated
sustained updrafts and multiple outflow boundaries providing
localized ESRH enhancements, but wind and rain look to be the two
main threats.
The complex as a whole should push off to the southeast Sunday
morning with some residual precipitation possibly lingering in
the far southeast CWA. H850 temps drop to +15 to +17C in the wake
of this system for Sunday, but by Sunday night the lower
tropospheric ridge will push east of the region and allow WAA to
overspread NE Kansas once again.
.LONG TERM...(Sunday night through Saturday)
Issued at 308 PM CDT Sat Jun 30 2018
The upcoming week features a return of hot summer temperatures
and few chances of precipitation.
The upper tropospheric ridge slowly retrogrades westward over the
course of the week; its centroid shifting from the southeast U.S.
to the Four Corners region by the end of the week. This will
result in highs hanging around the 90 to 95 degree mark and heat
indices in the 100-105 degree range. Any precip chances come later
in the week and are low/ill-timed at best.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1253 PM CDT Sat Jun 30 2018
Showers and thunderstorms are expected to develop late this
afternoon and persist through the overnight. Any showers and
storms during the afternoon/evening will likely be more scattered,
with the best chance for widespread restrictions coming
overnight. Winds will be from the south at 10 to 20 kts today,
veering to the northwest Sunday morning as a front moves through.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 7 PM CDT this evening for KSZ011-
012-022>024-026-036-038>040-055-056-059.
Heat Advisory until 7 PM CDT this evening for KSZ008>010-020-021-
034-035-037-054-058.
&&
$$
SHORT TERM...Skow
LONG TERM...Skow
AVIATION...Skow