Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/29/18
Area Forecast Discussion
National Weather Service Gaylord MI
1159 PM EDT Tue Aug 28 2018
.UPDATE...
Issued at 934 PM EDT Tue Aug 28 2018
A somewhat frustrating event, for certain, primarily chasing
around small and very brief spin-ups. Interesting to see a TDS
just nw of radar earlier on; may have had another in ne Otsego Co
a little later.
Line of strong convection will be exiting ne lower MI shortly.
Trailing stratiform precip is clearing out of nw lower MI, thanks
to post-MCS subsidence. But this will be temporary, as deep
convection over southern WI/northern IL sends additional showers
and perhaps a few rumbles of thunder our way from the sw
overnight.
Flood watch will be grudgingly maintained, for now anyways.
UPDATE Issued at 739 PM EDT Tue Aug 28 2018
Thunderstorm intensity is perhaps a little less than anticipated
to this point (especially given the relatively monstrous storms
that loomed just off of Leelanau as the event started). Still,
some brief spin-up looking features is making for some challenging
warning decisions.
Otherwise am fine-tuning timing of precip arrival in gridded and
text products.
Will begin removing some counties/marine zones from the watch (behind
the convective line) in the near future.
&&
.NEAR TERM...(Through Tonight)
Issued at 349 PM EDT Tue Aug 28 2018
...Severe storms, excessive rain possible...
High impact weather potential...severe storms this evening and
heavy rainfall tonight in northern lower MI.
Cold front is very slowly drifting south from the Straits area,
slowed by a wave along the front in ne IA/sw WI. Stratus is slowly
mixing out across eastern upper MI, though additional cloud cover
and even some convection is inbound from the w. A broken stratocu
deck covers a good portion of northern lower MI, with strong
sunshine now seen only near/s of an HTL-OSC line. That hasn`t
kept temps from creeping close to 80f under some portions of the
stratocu. And with dew points in the upper 60s, MlCape values are
slowly bubbling up past 500j/kg along and south of M-32, and some
1k j/kg values are merging near and s of TVC. More abundant
instability is seen to our west across WI, thanks to a series of
approaching shortwaves and associated cooling temps aloft (and
despite limited sunshine over that way). Evolution of convection
tonight, including svr and heavy rain threats, is the main
concern.
Overall trends in guidance are similar from this morning. A slightly
slower initiation, and a slight southward shift, continues in CAMs.
Instability will continue to slowly build, aided by deeper forcing
for ascent/cooling aloft arriving as 130+kt 300mb jet ejects across
northern Ontario. We are seeing a tongue of convection develop
eastward just w of GRB. This should continue to build eastward
toward roughly Leelanau Co and the M-32 tier of counties toward and
after 7 pm. Strong/svr cells are possible within this wing.
Trailing very quickly behind that will be the QLCS, making landfall
in parts of nw lower MI toward 8 pm. (A particularly intense cell is
already advancing across w central WI.) Various HRRR runs have had
multiple well-defined, small bow echoes with this section. The most
recent run does not, which is perhaps just a outlier, or is perhaps
indicative of instability not being quite as juicy as earlier
progged. The presence of the cell in w central WI suggests the
former. This line will exit off to the se toward midnight/1 am.
Wind damage is clearly the primary concern, and in nw lower MI
(where instability is highest and DCape is highest thanks to an
earlier storm arrival), some winds gusts appear possible. Some
large hail can also be expected. 0-3km helicities briefly push
300 in far sw portions of the forecast area early this evening.
This would produce some supercellular storm structures, and
perhaps a tornado or two (which our present low LCLs would
assist). Our surface winds are already backed along the Lake MI
coastline (FKS/MBL/LDM); that will be an area to watch.
The window for trailing cells across northern lower MI may be a
smidge shorter than it appeared earlier, which reduces the
potential for explosive rainfall amounts. Widespread 1-2" totals
are still a reasonable expectation, but getting way more than that
will be more difficult. That said, some of the highest amounts
continue to be progged in some of our more vulnerable locales
(Benzie Co into TVC), so will leave the flood watch alone.
Precip will not cleanly end as the business end of the QLCS departs
the forecast area. Showers and even a few storms will be thrown
up our way, as deep convection remains very active downstate. Risk
of sct showers will continue across all of northern MI all night.
Min temps will range thru the 50s in eastern upper MI, and thru the
60s in northern lower.
&&
.SHORT TERM...(Wednesday through Friday)
Issued at 349 PM EDT Tue Aug 28 2018
...Quieting Down...
High Impact Weather Potential...Minimal
Pattern Synopsis/Forecast...The models have the clearing during the
late afternoon, mainly, although the GFS is a little faster than the
ECMWF. However, it looks like the rain should be out of the forecast
area by early Wednesday evening, and skies clearing that night.
Thursday, high pressure will be over the region and the weather will
be quiet and cool.
Wednesday, the temperatures fall by 10 to 15 degrees from today and
remain around 70 on Thursday. It looks like fall is trying to make
an appearance.
Primary Forecast Concerns...Rain shower timing is a little
uncertain. This is the first major frontal passage coming through
for this time of year, and it has a major cool down post frontal.
This could cause issues as the cooler air moves over the the lake
and extends the clouds and rain into the afternoon. However the
drier air is suppose to push in enough by the late afternoon that
skies should begin to clear out.
.LONG TERM...(Friday night through Tuesday)
Issued at 349 PM EDT Tue Aug 28 2018
Extended (Friday through Tuesday)...High pressure builds into the
region and remains until Friday evening, before another system moves
into the Upper Great Lakes late Friday night/Saturday morning. The
cold front moves through during the day. The sky will clear out
overnight and will remain quiet through Labor Day weekend. Monday
night rain comes back into the forecast area late and affects the
region through Tuesday.
Temperatures warm to around 80 on Friday and slowly warms to the mid
80s or so by Tuesday, which will be about 5 to 10 degrees above
normal, with the normals in N Lower around the mid 70s and the in E
Upper around 70.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1159 PM EDT Tue Aug 28 2018
One more batch of rainfall will slide up through northern lower
Michigan during the overnight hours. Surface OBS reveal a mix of
IFR to VFR cigs across northern lower Michigan, leading to a
rather difficult terminal forecast. But incoming rainfall may tend
to improve cigs overnight, before crashing back to IFR early
Wednesday morning.
Cooler air spreads into the region on Wednesday. This will lead to
MVFR cigs through much of the day. Some clearing anticipated
Wednesday night.
Some NW gustiness is anticipated Wednesday.
&&
.MARINE...
Issued at 349 PM EDT Tue Aug 28 2018
Small craft advisory-level winds/waves on Lake MI will taper off
late today, as a cold front prepares to ooze southward across the
area. However, they will return on Wednesday as somewhat stronger
nw to n winds get ushered. The break period isn`t quite long
enough to be worth take advisories down and immediately putting
that up again, so have simply extended advisories on Lake MI thru
Wednesday. Additional advisories may also be needed on our other
waters Wednesday, but there is no need to issue those yet.
Another round of strong/svr storms is expected this evening,
especially near/s of the Manitous on Lake MI. Extreme winds are
at least an outside possibility there in the few hours.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...FLOOD WATCH until 8 AM EDT Wednesday for MIZ020>036-041-042.
LH...NONE.
LM...SMALL CRAFT ADVISORY until 6 PM EDT Wednesday for LMZ323-342-
344>346.
LS...NONE.
&&
$$
UPDATE...JZ
NEAR TERM...JZ
SHORT TERM...JL
LONG TERM...JL
AVIATION...BA
MARINE...JZ
Area Forecast Discussion
National Weather Service Buffalo NY
1031 PM EDT Tue Aug 28 2018
.SYNOPSIS...
Mid-summer heat and humidity will continue through Wednesday. A few
spotty showers are possible this evening across the western Southern
Tier, otherwise it will be mainly dry through Wednesday morning. A
strong cold front will then push through the region later Wednesday
and Wednesday night and produce showers and thunderstorms,
especially well inland from the Great Lakes. High pressure will then
bring much less humid and cooler air to our region Thursday and
Friday.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
An upper level ridge will remain across the southeast U.S. and
continue to promote very warm and humid conditions across the
eastern Great Lakes through Wednesday. Radar imagery showing a few
isolated showers still across the western Southern Tier. High
resolution guidance such as the HRRR and 3km NAM, while overdone,
generally have a handle on this and suggest the potential will last
for a few more hours through the early overnight. Otherwise the rest
of the area will remain mostly dry with mainly clear to partly
cloudy skies.
The upper level ridge will slowly track eastward and move off the
east coast overnight. A weak surface trough across eastern Ontario
and Quebec Provinces will drift south-southeast tonight. Showers and
thunderstorms will approach but mainly stay north of Lake Ontario
and the St. Lawrence Valley. The southern edge of the trough may
produce a few isolated showers over Lake Ontario late tonight, with
a few of these possibly reaching the North Country towards daybreak.
As we move into Wednesday morning, a cold front will continue to
approach the eastern Great Lakes as an upper level trough moves into
the Upper Great Lakes. The forecast area will have to cope with
another hot and breezy day as the cold front does not cross the
region until later in the day. Temperatures will climb into the mid
to upper 80s by afternoon, with a few lower 90s for areas southeast
of Lake Ontario. This will support another round of Heat Advisories
from the Genesee Valley into the western Finger Lakes and Central
NY.
A tight pressure gradient also persists through the day, with
southwest winds becoming gusty again on Wednesday. Southwest winds
will gust up to 40 mph in the typically windy locations northeast of
Lake Erie from the Niagara Frontier to Rochester, and also across
Jefferson County.
The cold front will move into eastern Ontario Province by Wednesday
afternoon. Showers and thunderstorms will begin to form across
inland areas, along and east of the enhanced flow off the lakes and
along the front in Canada. Instability will increase to 1-2k J/kg
with a moderate wind field of 30-35kts bulk shear. This will support
a marginal risk of severe weather as outlined by SPC, with the main
risk from the western Southern Tier into the western Finger Lakes
and points southeast of Lake Ontario. The remainder of the area will
be dominated by stable lake shadows, with lesser chances of rain and
lower severe potential northeast of the lakes. Most of this activity
will be mid afternoon through early evening. PWATS will be very high
as well and heavy rain will also be a threat in thunderstorms, but
fast storm motion will likely prevent any flash flood risk.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
A strong cold front will be in the process of moving through western
or central NY early Wednesday evening. High pressure will quickly
build into the northern Great Lakes region overnight and move east
across southern Ontario and Quebec on Thursday. This will result in
much drier and cooler weather across the area when compared to
earlier in the week. Afternoon highs should be about 15F lower -
mostly in the low 70s, while dewpoints fall through the 60s and end
up in the upper 50s by late Thursday afternoon. Low level moisture
will be trapped at about 5000ft with abundant inland strato cumulus
slowly dissipating late in the afternoon.
Thursday night...clear or mostly clear skies are expected as the
axis of the surface high to the north moves slowly east. This
should be a welcome relief with widespread lows in the lower or mid
50s, and even upper 40s in the coldest interior sections of the
Southern Tier and/or east of Lake Ontario.
Friday and Friday night...moisture and a little more warmth begins
to move in from the south. Current model forecast soundings are
still rather dry aloft but with several showing scattered showers in
the afternoon. This doesn`t look right and suspect they are
overdoing precipitation output - something we`ve seen often with the
current version of the GFS, although the NAM is also showing little
convective bullseyes. For now will keep shower potential down to
20% or less.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
High pressure will be centered over Newfoundland Saturday with
ridging extended southwest across New England and into New York
state. South winds on the back side of the riding will contribute to
an uptick in moisture/humidity with dewpoints rising into the mid
60s. A lack of a clear trigger has kept POPs limited to slight
chance favoring dry weather. High temps on Saturday will return back
to near or just above normal in the upper 70s to low 80s.
Sunday continues to look like the most probable period for
precipitation. The 12z global models now show what could be a
prefrontal trough and cold front crossing the lower Great Lakes
which could bring several rounds of convection. Have continued to
cap POPs at 40-50% with timing still needing to be nailed down.
Pwats will again run above 1.5 inches so heavy rain could be
possible with any storms along with a severe threat if enough
instability and wind shear is present. The GFS at this range is
showing around 3000 j/kg of SBCAPE and 25-30 knots of Effective wind
shear. It will remain quite humid ahead of the front with dewpoints
near 70. High temps are forecast to push into the low 80s.
Low/slight chance POPs linger into Sunday night and Monday with
potential for slower frontal passage or the boundary stalling near
the NY/PA border. Lowest POPs are in the North Country closer to a
fast moving weak area of high pressure. The airmass behind the front
only looks to provide a slight relief to humidity with highs
forecast near or just above normal. Have included slight chance POPs
for Tuesday with the EC showing another frontal passage. Highs temps
low to mid 80s.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
A few isolated to widely scattered showers will continue this
evening across the western Southern Tier. Otherwise the rest of the
area will stay dry through the early overnight with VFR prevailing.
A few showers may cross Lake Ontario late tonight and reach the
North Country by daybreak Wednesday, but these should remain spotty.
VFR will continue to prevail through early afternoon Wednesday.
Scattered showers and thunderstorms will then develop from mid
afternoon through early evening Wednesday as a cold front approaches
the eastern Great Lakes. The best coverage of thunderstorms is
expected from the western Southern Tier into the western Finger
Lakes and points southeast of Lake Ontario, with lesser coverage
northeast of Lakes Erie and Ontario with stable lake shadows,
including most of the TAF sites. The showers and thunderstorms will
end from northwest to southeast Wednesday evening with the passage
of the cold front.
It will become quite windy again Wednesday, especially northeast of
Lakes Erie and Ontario where gusts may reach 35 knots from mid
morning through late afternoon.
Outlook...
Thursday...A chance of leftover showers/MVFR CIGS in the morning...
otherwise mainly VFR.
Friday...Mainly VFR.
Saturday and Sunday..Mainly VFR with a chance of showers and
thunderstorms.
&&
.MARINE...
Southwest winds will rapidly diminish through the evening hours with
the loss of diurnal mixing, with waves also coming down steadily on
the lakes. A strong pressure gradient remains in place Wednesday
ahead of a cold front approaching the eastern Great Lakes. This will
produce another round of moderate to strong southwesterly winds on
Lakes Erie and Ontario, with Small Craft Advisories in place again
for most areas.
The aforementioned cold front is then expected to press southeastward
and across the Lower Lakes later Wednesday and Wednesday night while
generating scattered showers and thunderstorms...some of which could
potentially feature strong, gusty winds and locally higher waves. In
its wake, Canadian high pressure is then expected to build across
the region Thursday and Friday, while bringing about a return to
fair weather and calmer conditions.
&&
.CLIMATE...
A strong sub tropical ridge to our south will pump oppressively warm
and humid air across our region through Wednesday. While it will
be very warm, the record high temperatures for Wednesday at the
climate sites are not likely to be reached.
Record Highs for Wednesday...
Buffalo 90 (1951)
Rochester 94 (1973)
Watertown 89 (1953)
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Heat Advisory until 8 PM EDT Wednesday for NYZ003>006-013-014.
MARINE...Small Craft Advisory from 8 AM to 8 PM EDT Wednesday for
LEZ020-040-041.
Small Craft Advisory from 11 AM to 8 PM EDT Wednesday
for LOZ045.
Small Craft Advisory from 8 AM to 8 PM EDT Wednesday for
LOZ042-043.
Small Craft Advisory from 11 AM to 8 PM EDT Wednesday
for SLZ022-024.
&&
$$
SYNOPSIS...Hitchcock/HSK
NEAR TERM...Hitchcock/HSK
SHORT TERM...Zaff
LONG TERM...Smith
AVIATION...Hitchcock/HSK
MARINE...Hitchcock/HSK
CLIMATE...Hitchcock
Area Forecast Discussion
National Weather Service State College PA
1110 PM EDT Tue Aug 28 2018
.SYNOPSIS...
Wednesday will stay hot and humid. But, an approaching cold
front will bring the chance of showers or thunderstorms to
northwest Pennsylvania Wednesday evening, and scattered showers
and isolated thunderstorms to much of the rest of the area
overnight. A return to near normal temperatures and more
comfortable humidity will occur in the wake of the front on
Thursday and Friday. A ridge of high pressure will build across
the region late this week, likely followed by the passage of a
warm front on Sunday.
&&
.NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/...
Yup. Just the tiniest showers have been able to pop up over the
NW as the convergence along the old lake breeze and lift from
an extremely weak short wave coincide. These should not last
much longer, with mainly high clouds for the second half of the
night.
Prev..
Just the tiniest shower or two possible over the nrn mtns this
evening. Otherwise, the cu field has disappeared and stability
is taking over.
Prev...
A subtropical ridge extending from the Central Appalachians to
off the Carolina Coast will maintain clear to partly cloudy
skies and hot conditions for the rest of the daylight hours.
Temps are closing in on fcst highs ranging from the mid to upper
80s over the Alleghenies of northern and western PA, to the
lower and middle 90s over the Susq Valley.
The combination of heat and high humidity will result in
afternoon heat indices between 100-104 over the Susq Valley.
Warm temps aloft will largely limit the vertical growth of
otherwise MDT cu this afternoon across most of Central and
Northern PA.
The latest HRRR indicates no measurable QPF from convection for
the rest of this afternoon, except for a sliver of showers
and possibly a few tsra moving inland as far as KBFD early this
evening. The initial convection is expected to form near the
Lake Breeze boundary, that`s currently seen on GOES East Vis
imagery helping to expand the cu field over far SW New York
State west of KJHW.
The HREFV2 continues to indicate a scattering of showers and
perhaps a couple of isolated thunderstorms until about 23Z today
from the SCENT mtns. 0-6km mean wind indicates any storms that
initiate over the higher terrain of southern PA would drift
eastward toward the Lower Susq Valley.
Weak shear profiles suggest any storms will be of the pulse
variety with little chance of organized severe weather.
&&
.SHORT TERM /8 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
Any isolated, pulse-type thunderstorms over the southern
counties should die with loss of heating this evening.
Otherwise, expect another warm and muggy night with some patchy
late night fog possible. SREF prob charts suggest the fog will
not be as widespread as this morning.
Warm temps aloft and a ribbon of relatively lower pwats should
ensure another hot but rain-free day across most of central Pa.
The best chance of showers/storms will come late in the day or
evening across the northwest counties in association with a cold
front pushing southeast from the Grt Lks. Increasing mid level
flow and shear noted ahead of this feature could support a few
stronger storms across the northwest Pa. Will also have to
watch for the possibility a couple pulse-type tstorms firing
during the afternoon across the southeast counties, where GEFS
places a ribbon of higher pwats/instability.
Based on collaboration with neighboring offices extended the
Heat Advisory for our Susq Valley and Scent Zones through 00Z
Thursday, since we will remain in the same air mass and expect
to see another msunny day.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
The cold fronts timing remains fairly consistent as it will
move slowly across central PA on Thursday. Showers and
thunderstorms will fade Wednesday night before the daytime
convection should help restart them Thursday afternoon across SE
PA. SPC only has the region in general thunder. The front should
still stall and pivot. It will then return northward as a warm
front late in the weekend. The close proximity of this front
will keep our weather unsettled through Labor Day, with the
chance of a shower or thunderstorm each day. Low level southeast
flow may result in a good deal of low clouds and cooler daytime
temperatures Saturday. However, 12Z NAEFS indicates the
subtropical upper ridge will rebound over the Eastern U.S. and
maintain above average temperatures and muggy/humid conditions
Sunday into early next week.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
For the late evening TAFS, added shower to BFD. Showers should
be gone soon.
Earlier discussion below.
For the 00Z TAF package, other than some fog across the
Susquehanna Valley late, not seeing much potential for fog,
clouds, or showers overnight. Higher dewpoints and lighter
winds to the east and south, give that area more potential for
fog.
Strong high pressure sfc and aloft should keep most of the
area dry on Wed. Perhaps a shower across the northwest late,
added in VCSH at BFD.
Activity for Wednesday evening looks to be along or just behind
the cold front, not a lot of support, thus showers and storms
will most likely weaken as they move to the east and south
overnight.
Some showers and storms will be possible on Thursday, mainly
across the east and south.
.Outlook...
Wed PM-Thu...Mainly VFR, with more organized SHRA/TSRA
possible with cold frontal passage.
Fri...AM restrictions (as low as IFR or LIFR) in fog/stratus,
then VFR.
Sat...Mainly VFR.
Sun...Chance of showers and storms.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT Wednesday for PAZ028-036-046-
049>053-056>059-063>066.
&&
$$
SYNOPSIS...Lambert
NEAR TERM...Dangelo/Lambert
SHORT TERM...Lambert
LONG TERM...Ceru/Steinbugl
AVIATION...Martin
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
633 PM CDT Tue Aug 28 2018
.AVIATION.../00Z TAFS/
High pressure and southerly flow will remain in place. May see deeper
moisture further west on Wednesday and this may help to produce
convection closer to or along I-35. For this forecast have opted to
leave out the mention of convection due to uncertainties that
currently exist. VFR conditions will become MVFR in the 07Z-09Z
period as stratus develops. Should see the MVFR cigs return to VFR
between 14Z and 16Z. S/SE winds 10-15 knots with gusts to near 20
knots through 06Z then southerly winds 10 knots or less. Convection
to the east is decreasing but has produced an outflow boundary that
will likely impact the AUS terminal right about 00z. This boundary
will cause winds to become more E/SE for an hour or two and produce
gusts of 20-25 knots. DRT will see easterly winds after 02Z then back
to SE around 16Z at speeds of 10-15 knots with gusts to around 20
knots.
&&
.PREV DISCUSSION... /ISSUED 247 PM CDT Tue Aug 28 2018/
SHORT TERM (Tonight through Wednesday Night)...
Hot conditions continue across South Central Texas this afternoon.
Better moisture is confined across the far eastern CWA. HRRR
depicting isolated convection developing through the late afternoon
into portions of Lavaca, Fayette, Lee, and Bastrop counties before
dissipating around sunset.
A weak inverted mid level trough, beneath the ridge to the northeast,
will move inland through the eastern half of the CWA on Wednesday.
Deeper moisture values are progged to reach as far inland as the I-35
corridor, with precipitable water values progged near 1.8-2.0 inches.
This should allow for convection to develop during the afternoon
through sunset across central and eastern areas of the CWA. Coverage
should overall remain isolated given weak nature of the mid level
forcing and sea-breeze.
LONG TERM (Thursday through Tuesday)...
A flat ridge will become established Thursday through Saturday near
and north of the CWA. Models linger moisture and low chances for
isolated afternoon convection across mainly far eastern areas of the
CWA during this time. Otherwise warm temperatures continue to be
above normals.
Models continue to indicate slightly better chances for rainfall
early next week as a deeper fetch of moisture and inverted mid level
from the Gulf of Mexico move west, beneath the ridge to the north of
northeast. There is still some uncertainty on exact placement of the
ridge and thus uncertainty with westward extent inland this moisture
reaches, so at this time will continue to keep PoPs in 20-30% range.
Temperatures do appear to trend slightly cooler.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 78 100 77 98 77 / 0 20 20 20 10
Austin Bergstrom Intl Airport 78 98 76 98 75 / 0 20 10 20 10
New Braunfels Muni Airport 76 100 75 97 75 / 0 20 10 20 10
Burnet Muni Airport 75 97 74 96 73 / 0 10 20 10 -
Del Rio Intl Airport 78 100 77 98 77 / 0 0 10 10 10
Georgetown Muni Airport 78 99 75 97 75 / 0 20 20 20 -
Hondo Muni Airport 76 100 75 98 74 / 0 - 20 10 10
San Marcos Muni Airport 78 98 76 97 75 / 0 20 10 20 10
La Grange - Fayette Regional 78 97 75 96 75 / 10 30 10 20 10
San Antonio Intl Airport 78 99 77 97 77 / 0 10 20 20 10
Stinson Muni Airport 78 100 77 98 77 / 0 20 20 20 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Mesoscale/Aviation...10
Synoptic/Grids...05
Public Service/Data Collection...BMW
Area Forecast Discussion
National Weather Service Green Bay WI
1026 PM CDT Tue Aug 28 2018
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Wednesday
Issued at 218 PM CDT Tue Aug 28 2018
The latest RAP analysis and satellite/radar imagery show a cold
front stretching from La Crosse to Wausau to the tip of Door
County early this afternoon. Widespread low clouds surged
southeast late this morning to cover most of north-central and NE
WI, setting up a relatively tight temp gradient across the region.
A band of showers and storms continues to track northeast behind
the front and into north-central WI within a zone of mid-level
fgen. Meanwhile, more cellular thunderstorms are developing ahead
of the front and along/south of an outflow boundary over
southwest WI and northeast IA. Despite widespread low clouds, ML
capes of 1500-2500 j/kg and deep layer shear of 45-50 kts
continues to point towards a severe storm threat developing south
of a Marshfield to Oconto to Sturgeon Bay as storms push
northeast along this outflow boundary and ahead of the front
through the rest of the afternoon. Given storm evolution to our
southwest, will extend the flash flood watch across Waupaca and
Portage counties. Damaging winds and torrential rains will be the
main threat, and hail to a lesser extent. Also cannot rule out an
isolated spin up given the beefy 0-3 km shear vectors.
Tonight...Shower and thunderstorm chances will be ongoing across
much of the region at 00z. Based on the latest HRRR runs, it
appears that the strongest thunderstorm activity will be occurring
over east-central WI early this evening, but then exit the area
around 02-03z. Therefore it appears the best chance of severe
weather will continue through that time period before evolving
into more of a heavy rain with embedded storms scenario. Potential
for flooding remains possible in the flash flood watch area due
1-3 inches of rainfall in the forecast, with locally higher
amounts. Precip will exit to the east overnight, with widespread
clouds and cooler conditions moving across the area.
.LONG TERM...Wednesday Night Through Tuesday
Issued at 218 PM CDT Tue Aug 28 2018
Wednesday through Thursday: The cold front that produced all the
active weather over the past couple days will continue to shift off
to the east of the area through the day Wednesday. At the same time,
a dry surface ridge will slide across the CWA through this time
period. Aloft, the upper level trough axis will swing through the
Western Great Lakes region during the day Wednesday as heights begin
to rise Wednesday night into the day Thursday. The weather will be
much cooler and fairly quiet. High temperatures will be in the 60s
to around 70. Humidity values will drop as well, leading to more
comfortable conditions.
Thursday night through Saturday: The surface ridge and upper-level
ridge will slide to the east Thursday night allowing for a more
moist southerly return flow into the Western Great Lakes. These
features will continue eastward through Saturday as as a more
wrapped-up surface low and closed upper level low slides from
Manitoba into Hudson Bay. This will drag a cold front across the CWA
Friday afternoon into Friday night. Additionally, a shortwave is
progged to slide through the Western Great Lakes as well. While the
overall instability will be determined by the exact timing of the
front, it does look like enough instability will be around to
increase the risk of thunderstorms. Models are depicting around 20
to 30 knots of deep-layer shear ahead of the front, so severe
weather is not out of the question. Again, if the front comes
through during peak heating, the chances of severe weather will
increase, while a delay toward the later evening hours would result
in a diminished severe potential. Temperatures for this time period
will warm to above normal, once again, with highs in mid to upper
70s to low 80s.
Saturday night through Monday: Medium range models then point toward
the cold front shifting to the east of the area Saturday night with
dry high pressure building in on Sunday. At the same time, upper-
level flow is expected to become nearly zonal across the Western
Great Lakes. This will lead to near normal temperatures for this
time period with only small chance of showers and thunderstorms,
mainly on Monday. This is basically what the consensus of the models
is showing.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1021 PM CDT Tue Aug 28 2018
Occasional showers and a few embedded thunderstorms (mainly
southeast) should taper off from west to east overnight. As a
cold front makes a push south of the region overnight, low clouds
will overspread the entire region, with ceilings dropping to IFR
at most locations. High pressure will build into the region on
Wednesday, causing low ceilings to rise in the morning and break
up in the late morning and early afternoon. VFR conditions should
prevail over most of the forecast area by early afternoon.
Northwest to north winds will become a bit gusty overnight into
Wednesday, before diminishing later in the day.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Cooley
AVIATION.......Kieckbusch
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1035 PM EDT Tue Aug 28 2018
.SYNOPSIS...
A strong upper level ridge will persist over the area through
midweek and then drift off the east coast on Thursday and Friday,
which will result in hot and humid conditions through the end of
the work week. A cold front will approach from the north by the
end of the week as the ridge temporarily weakens, but is expected
to stall. The upper ridge will then build back over the Southeast
states this weekend.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 1030 PM: All of the diurnal convective activity has now
dissipated, and a dry fcst still is expected for the remainder
of the night. 00z HiRes Windows are essentially free of activity
in our area, and HRRR continues to show only occasional blips of
convection that seemingly can be attributed to model noise. Patchy
fog is still possible across a good portion of the area tonight,
particularly in the mountain valleys. Did update temp/dewpt trends
overnight and made slight revisions to low temps.
The subtropical ridge will remain dominant over the southeast
through the near-term period. This will lead to above-climo
temperatures. The HRRR and RAP have trended downward in their
depiction of precip overnight tonight, and with forcing from
the southerly flow expected to be weak, a dry forecast for the
overnight hours still looks appropriate. A diurnal pattern of
isolated piedmont to scattered mountain convection is expected on
Wednesday afternoon, similar to what happened today, but with more
southwesterly steering flow. Max temps will once again be about
five degrees above climatology.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 230 PM EDT Tuesday: Per latest guidance, a cold front off to
northwest will continue to drop southeast towards the area Wednesday
night and Thursday, but will struggle to reach the FA towards the
end of the week as high pressure previously across the Great Lakes
wedges back in across the area from the northeast into Friday. With
Bermuda high somewhat retreating off to the east and upper ridging
weakening slightly overhead, continued southerly flow will allow for
plenty of moisture to infiltrate into the area with the continued
typical summertime pattern - warm and humid conditions. Instability
will be in place each day along with weak shear, thus diurnal
convection is expected both Thursday and Friday. Would not entirely
rule out a few severe thunderstorms, but overall am not anticipating
widespread severe threat. As for QPF, have kept higher PoPs along
the NC mountains both days.
Temperatures will remain just above normal through the forecast
period, though temperatures on Friday will be just a few degrees
cooler than Thursday.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 215 PM EDT Tuesday...the medium range looks very much like
the climatological normal for this time of year. A weakness aloft
between the Atlantic subtropical ridge and another upper anticyclone
over the srn Plains will gradually weaken through the weekend. As
a result, we might not see much of a dropoff in precip chances
late at night on Friday night and Saturday night. The trend going
forward will be back to climo for early next week. The Atlantic
subtropical ridge is expected to re-assert itself as the center
of the high drifts back to the west. We remain in a light but
relatively deep SE to S flow as a consequence. Mainly diurnal
precip chances will favor the mtns because any convection that
develops over the mtns and foothills would tend to get pushed to
the N or NW. This pattern should also favor temps within a category
or normal through the period.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: High pressure remains dominant over the
region and another rather uneventful night is expected at the
Piedmont sites. Though a few showers do exist south and east of KCLT
at issuance time, these are moving slowly enough they are expected
to fizzle out before they reach the field. KCLT did take a hit from
a t-storm during the afternoon, and with relatively humid conditions
overnight, brief fog is expected, though probably still VFR. KAVL
bears some chance of fog being in the valley, though mixing this
aftn was more effective than previous days in drying the PBL. Hence
IFR is looking less likely, and is only reflected in TEMPO. Light
S to SW winds continue thru the period. As moisture continues to
return to the area on this flow, TSRA chances Wed aftn are a bit
higher than we have seen in the past several days. A mention of
precip is made at all sites except KHKY.
Outlook: Scattered diurnal showers and thunderstorms are expected
each afternoon, expanding to include slightly more of the piedmont
and foothills for Thursday afternoon onward. Areas of fog and
low stratus can also be expected each morning, primarily in the
mtn valleys. This moderately unsettled pattern will continue into
early next week.
Confidence Table...
02-08Z 08-14Z 14-20Z 20-00Z
KCLT High 100% High 100% High 100% High 100%
KGSP High 100% High 93% High 100% High 100%
KAVL High 93% High 93% High 100% High 100%
KHKY High 100% High 93% High 100% High 100%
KGMU High 100% High 100% High 100% High 100%
KAND High 100% High 100% High 100% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...PM
NEAR TERM...HG/Wimberley
SHORT TERM...SGL
LONG TERM...PM
AVIATION...Wimberley
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
547 PM CDT Tue Aug 28 2018
.SHORT TERM... (Through Late Wednesday Afternoon)
Issued at 357 PM CDT Tue Aug 28 2018
The primary concern through Wednesday afternoon is thunderstorm
trends. A cold front continues to move slowly southeast through far
southeast Nebraska into northwest Missouri this afternoon showers and
thunderstorms are ongoing ahead of the front in northwest Missouri,
and this activity should continue to move east through the late
afternoon into this evening. RAP and NAM continue to maintain some
fairly impressive MUCAPE values in excess of 2000 J/Kg through the
night. However both models tend to be a little too warm on both dew
point and air temperature in the boundary layer. The GFS diminishes
instability to less than 1500 J/Kg ahead of the front pretty quickly
this evening, which would be less favorable for severe storms
tonight. All three models show 0-6km shear around 30kts across
northeast Missouri and west central Illinois, which is enough for
organized severe thunderstorms IF the instability is high enough.
Given the tendency of the RAP and NAM to overestimate instability, I
am leaning toward the GFS solution. The SPC slight risk may
therefore be a little overdone under the circumstances. Convection
allowing models aren`t showing anything particularly
threatening...just scattered strong thunderstorms or a broken line
moving southeast through the forecast area tonight, so this lends
some additional credibility to the weaker solution. That being said,
scattered strong and possibly a few isolated thunderstorms will be
likely, especially late this evening while the heat of the day
lingers. Some training storms are also possible due to the slow
movement of the front. Forecast QPF was not especially high, but
did put around 1-1.5 inch up in parts of northwest Missouri so am
keeping a little locally heavy rain mention in the forecast.
The front continues pushing southeast through Missouri and Illinois
on Wednesday, and guidance has been consistently stalling it over
the Ozarks as upper level support moves east. The broken line of
showers and storms left over from tonight`s convection will likely
fall apart...potentially dissipating completely after sunrise
Wednesday morning. However, weak convergence along the front and
rich boundary layer moisture should allow additional development by
late morning or early afternoon. Not very confident on the
convective mode of Wednesday`s storms, as shear will be only around
10-20 kts. However, the GFS is forecasting over 3000 J/Kg MLCAPE
south of the front Wednesday afternoon. Think organized multicells
are most likely possibly growing upscale into small lines if local
conditions can support it.
Carney
.LONG TERM... (Wednesday Night through Next Tuesday)
Issued at 357 PM CDT Tue Aug 28 2018
Main focus thru the period will be temps.
A cdfnt that is progd to push thru the area on Wed is expected to be
south of the CWA at the start of the forecast period 00z Thurs. The
pattern aloft becomes zonal while a sfc ridge builds into the region
at the sfc. This flow will help push the Bermuda high south of the
area. Even with the sfc ridge remaining over the region on Thurs,
given the 588 dam heights over the region along with 850mb temps
around 20C, would expect temps to remain fairly warm. Have trended
twd the warmer guidance for Thurs.
The sfc fnt will lift back north thru the region as a wrmfnt on Fri.
This begins the warming trend thru the end of the forecast period.
Have tempered the warm up slightly due to some question regarding
the placement of sfc boundaries.
While a wrmfnt shud lift north of the area, mdls suggest a residual
sfc boundary remaining across the region. Given this sfc boundary,
zonal flow aloft and sly to swly flow thru the low levels, have kept
some PoPs across much of the area thru the weekend and into early
next week. The GFS has a more sly soln regarding precip while the
ECMWF has a more nly track. Have therefore kept PoPs on the lower
side of chance expect for a few periods/areas where confidence is
higher and mdls are in better agreement.
The upper ridge builds back into the region and sfc flow becomes sly
to swly again on Mon and Tues. Have therefore trended temps above
MOS thru this period. While there are some indications that the
going forecast may be too cool, uncertainty is too low attm as the
sfc ridge still maintains some control across the area, especially
the ern half of the CWA.
Tilly
&&
.AVIATION... (For the 00z TAFs through 00z Wednesday Evening)
Issued at 519 PM CDT Tue Aug 28 2018
A cold front will move southeastward through the taf sites late
tonight and Wednesday morning. Thunderstorms just ahead and along
the front will impact UIN and COU late this evening and
overnight, and the St Louis metro area by early Wednesday
morning. Post frontal MVFR cloud ceilings are expected late
tonight and Wednesday. South-southwesterly surface winds will
veer around to a northwesterly direction after fropa, mainly
Wednesday morning.
SPECIFICS FOR KSTL: A cold front will move southeastward through
the STL area Wednesday morning. Thunderstorms just ahead and
along the front will impact STL by early Wednesday morning. Post
frontal MVFR cloud ceilings are expected Wednesday. South-
southwesterly surface winds will veer around to a northwesterly
direction after fropa late Wednesday morning.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Heat Advisory until 7 PM CDT this evening for Audrain MO-Boone
MO-Callaway MO-Cole MO-Franklin MO-Gasconade MO-Knox MO-
Lewis MO-Lincoln MO-Marion MO-Moniteau MO-Monroe MO-
Montgomery MO-Osage MO-Pike MO-Ralls MO-Shelby MO-Warren MO.
Excessive Heat Warning until 7 PM CDT this evening for Jefferson
MO-Saint Charles MO-Saint Louis City MO-Saint Louis MO.
IL...Heat Advisory until 7 PM CDT this evening for Adams IL-Bond IL-
Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey
IL-Macoupin IL-Marion IL-Montgomery IL-Pike IL-Randolph IL-
Washington IL.
Excessive Heat Warning until 7 PM CDT this evening for Madison
IL-Monroe IL-Saint Clair IL.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Marquette MI
807 PM EDT Tue Aug 28 2018
.SHORT TERM...(This evening through Wednesday)
Issued at 414 PM EDT TUE AUG 28 2018
WV imagery and RAP analysis indicated a broad mid/upper level trough
through the northern and central plains and a ridge over the
southeast CONUS resulting in sw flow into the nrn Great Lakes.
A prominent upstream shortwave trough was moving into wrn IA. At the
surface, a frontal boundary extended form northern Lake Michigan
through central WI into sw IA with dewpoints into the mid 70s south
of the front. Areas of strong thundestorms with heavy rain have
developed near the front where MLCAPE values had climbed to around
3k J/Kg. Otherwise, only scattered light showers were observed
through nrn WI.
Tonight, expect the showers to expand into mainly the southeast half
of Upper Michigan through 06z, supported by 700-300mb qvector conv
ahead of the shrtwv and upper level divergence associated with the
right entrance of the jet into nrn Ontario. However, the stronger
convection to the south will inhibit moisture flow to the north,
limiting pcpn amounts. Some isold tsra may also develop over the
south where MUCAPE values into the 1000-1500 J/Kg will linger. Any
rain that develops should taper off overnight.
Wednesday, with abundant low level moisture lingering across the
area, patchy drizzle or isold -shra is expected over the north in
the morning, especially where upslope flow prevails. Clouds will
only gradually diminish during the afternoon resulting in high temps
from aound 60 north to the mid and upper 60s south.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 412 PM EDT TUE AUG 28 2018
Quiet weather to start the long term. High pressure and prime
raditional cooling may allow temps in favored cold spots on Wed
night to drop into the upper 30s. On Thu temps rebound compared to
Tue/Wed with some 70s showing back up over the west. As high slides
to eastern Canada late Thu into Fri, low pressure trough moves to
south central Canada to central Plains. South winds ramp up ahead of
the trough and could be gusty late Thu through Fri. South winds and
H85 temps above 15C may even allow some downslope areas near Lake
Superior to reach 80F. Looks more humid on Fri as well though not
to the extent experienced ahead of the recent cold front.
May see showers and t-storms advecting into western Upper Michigan
as early as Fri morning on edge of greater instability over MN to
northern Ontario. Primary trough passage occurs late Fri or Fri
night as upper level trough edges over the Upper Great Lakes. Given
extent of instability and wind fields aloft/higher PWATs, could be
stronger storms as the front moves through late Fri into Fri night.
Lingering showers and possible t-storms could still continue on Sat
with greater chances over the south and east unless the main frontal
system slows down compared to what models show attm. Trough axis and
sfc ridge moving in should lead to diminishing rain chances by Sat
aftn for west half of the forecast area and by Sat evening for the
east half of the forecast area. Flow aloft ridges in behind the
trough on Sun leading to dry weather then another chance of showers
and t-storms move back in for Labor Day into next Tue. Daytime temps
Sun through Tue should top out in the mid to upper 70s, which is
slightly above normal.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 807 PM EDT TUE AUG 28 2018
Lingering low-level moisture and an upslope northerly wind will
likely keep LIFR conditions in place thru tonight at KIWD/KSAW. At
KCMX, less favorable upsloping should allow LIFR conditions to
improve to low MVFR overnight. Some -dz/-shra will also be possible,
especially at KSAW. Drier air will make inroads into the area on Wed
as high pres approaches from the w and nw. This will result in
improvement to VFR from nw to se thru the day, beginning first at
KCMX.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 414 PM EDT TUE AUG 28 2018
North winds to around 20 knots will develop late tonight into early
Wednesday as low pressure sdlies to the southeast of the area.
Otherwise, winds will remain at or below 20 knots through Friday and
then will increase up to 25 knots Friday night and Saturday when
gusts to 25 knots are possible.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Beach Hazards Statement until 10 PM EDT this evening for MIZ014.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...Rolfson
MARINE...JLB
Area Forecast Discussion
National Weather Service Pueblo CO
311 PM MDT Tue Aug 28 2018
.SHORT TERM...(This evening through Wednesday)
Issued at 239 PM MDT Tue Aug 28 2018
The NAM and the HRRR continue to show no precip over southern CO
this evening. The GFS shows precip developing along the I-25
corridor, mainly over Pueblo and Custer counties and northward this
evening and then spreading east over the plains thru late night.
Will lean more toward little or no precip.
The forecast models show the potential for low clouds over most of
the southeast plains tonight, as low level upslope winds continue.
The areas that will likely see the best chances for low clouds, or
the thickest cloud cover, will probably be along and near the
eastern mtns, including the I-25 corridor, and areas south of
Highway 50. The NAM shows the potential for light stratiform precip
under this low cloud cover over portions of the southeast plains
overnight. The low clouds are then expected to gradually decrease
thru the morning hours Wed, lingering the longest over the far
southeast plains. Wed afternoon looks dry acrs southern CO, with
high temps that are similar to today`s temps.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 239 PM MDT Tue Aug 28 2018
Wednesday night to Thursday Morning
There will be dry upper-levels and moist lower-levels that will
introduce around 1500 J/kg of CAPE on Wednesday evening in to
Thursday morning. The potential of a nighttime thunderstorm is
possible around the midnight hour. There is some model divergence
that needs to be realized, as well. The ECMWF and the GFS both
highlight thunderstorms developing over the Palmer Divide, Wet
Mountains, and the southern Sangre de Cristo Mountains. The NAM
highlights a weak ridge aloft which would impede thunderstorms,
whereas the GFS and the ECMWF indicate a more zonal flow aloft which
would allow a weak shortwave trough to potentially spark
thunderstorms. WPC model discussions favor a non-NAM blend,
bringing some merit of the weak nocturnal thunderstorm outcome
occurring, some elevated PoPs will be put in the forecast grids.
The previously mentioned thunderstorms will dissipate during the
morning hours. The low temperatures will range the mid 50s to low
60s across the plains, mid-to-upper 40s in the mountain valleys,
and 30s for the mountains.
Thursday...
West to Southwest dry upper level flow will protrude over Southern
Colorado on Thursday, which translates to dry and hot conditions for
the plains and isolated thunderstorms over the mountains. Some gusty
winds will be experienced over the far eastern plains during the
afternoon to evening hours. The far eastern plains will have
relative humidity values around 15 to 25 percent when the winds will
be strongest, meaning that critical fire conditions will not be met.
High temperatures during the day will range from the mid-to-upper
90s, with isolated locations reaching 100F, across the plains, low-
to-mid 80s for the mountain valleys, and 50s to low 70s for the
mountains (depending of elevation).
Friday and Saturday...
Friday will be similar to Thursday. Dry upper level west to
southwest flow, warming the plains and sparking an isolated
thunderstorm over the mountains. Surface winds, in general, will be
weaker than Thursday, meaning that critical fire conditions will
once again not be met. Later Friday evening, a cold front will
propagate over the region and behind that cold front will be moist
upslope flow, which could spark some showers and thunderstorms over
the eastern mountains and eastern plains during the evening and
overnight hours. Temperatures on Friday will be slightly cooler, but
similar to Thursday. Saturday, however, temperatures will be much cooler
due to the colder air mass behind the cold front. Expect
temperatures in the mid-to-upper 80s over the plains, upper 70s to
low 80s over the mountain valleys, and 50s to low 70s (depending
on elevation) for the mountains.
Sunday through Tuesday...
A wetter pattern appears to be setting up during this time period,
with a combination of a ridge building over the desert southwest
that has similarities to a monsoonal pattern and upper-level
troughs propagating over the region. With all of this activity,
temperatures are expected to remain similar to what they will be
on Saturday, which is near normal for this time of year.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 239 PM MDT Tue Aug 28 2018
VFR conditions are expected at KCOS and KPUB thru early this
evening. KCOS could see isolated showers/tstms nearby in the
evening. Forecast models are showing low clouds moving into KCOS and
KPUB this evening and continuing into Wed morning. KPUB could see
ceilings lowers into MVFR category or stay just above, in the VFR
category. KCOS will likely see MVFR conditions. Low clouds at KPUB
and KCOS should mostly dissipate by midmorning.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...28
LONG TERM...SKELLY
AVIATION...28
Area Forecast Discussion
National Weather Service Raleigh NC
1040 PM EDT Tue Aug 28 2018
.SYNOPSIS...
An area of high pressure centered over the Carolinas through mid
week will shift east late in the week allowing a cold front to
approach from the west. The upper level ridge will build back over
the Southeast states late this weekend and into early next week.
&&
.NEAR TERM /OVERNIGHT/...
As of 1040 PM Tuesday...
00Z upper air analysis depicts a stacked high pressure system over
central NC. This weather system will maintain warm and dry
conditions through the overnight into Wednesday morning.
Some of the NAM based model iterations suggest a decent chance for
low clouds and fog across portions of the Sandhills and southern
Coastal Plain. Other models such as HRRR and GFS suggest little if
any fog or low clouds by early Wednesday. Overnight temperatures
generally near 70 to the lower 70s.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
As of 310 PM Tuesday...
The upper level ridge will shift east slightly by Wednesday
allowing mid level temperatures to cool slightly and perhaps
produce a little less subsidence. With this in mind, expect a
little bit more convective coverage, especially across the south
and west on the periphery of the ridge center. NAM dynamic
tropopause maps suggest a disturbance will rotate across these
areas during the afternoon. With little forcing for ascent,
expect any convection to fade around sunset. Expect
high temperatures very close to today with highs in the lower
90s. Lows Wednesday night will again range in the lower 70s.
-Blaes
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 234 PM Tuesday...
Today`s NWP guidance suggests a persistent pattern will be in place
most, if not all of, the long term period. The main feature will be
an elongated mid/upr ridge that is progged to stretch across most of
the South, the Carolinas, and then out across the western Atlantic.
Its worth noting that the short wave trough that is currently moving
into the northern plains region is progged to move east and by to
our north over the next 36 hours, and in the process will produce a
weakness in the aforementioned elongated ridge. This weakness,
along with a plume of deeper moisture, will be positioned just to
our west through much of the long term. As for central NC, given
that we are not expecting any airmass changes leading into the long
term period, forecast soundings show adequate moisture and
instability to support at least a climo PoP (25-30%) each day, for
mainly diurnal showers and thunderstorms. Low level forcing
mechanisms will include the piedmont trough, the sea breeze across
our eastern zones, and outflow boundaries. Highs each day will be
within a degree or two either side of 90, and lows in the lower 70s.
&&
.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
As of 715 PM Tuesday...
24 hour TAF period: VFR conditions are expected to prevail across
nearly all of central NC through the period, with some areas of IFR
and possibly LIFR fog and stratus around daybreak across the
Sandhills and Coastal Plain.
Skies across central NC this afternoon feature mainly scattered to
occasionally BKN cumulus clouds with bases between 4-5kft.
Isolated convective coverage has diminished rapidly as the sun
continues to set Tuesday evening. This trend is expected to continue
into the overnight hours with southerly surface winds also becoming
light and variable. Fog/stratus formation is certainly not a slam
dunk, but best formation conditions will continue to reside in the
southern sandhills and eastern coastal plain counties around
daybreak Wednesday. Have treated this with a tempo group for now
until confidence on trend increases. Shower/storm development on
Wednesday should remain isolated, so have left off VCTS for now
until confidence increases.
Looking ahead: Areas of late night and early morning fog and/or low
stratus is expected, mainly across the Sandhills and Coastal Plain
through the period. The threat of mainly afternoon and evening
showers and thunderstorms will increase as we head into the
weekend. The greatest threat of adverse aviation conditions is
expected on Thursday through Saturday.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Blaes
NEAR TERM...WSS
SHORT TERM...Blaes
LONG TERM...NP
AVIATION...JJM/Blaes