Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/11/25
Area Forecast Discussion
National Weather Service State College PA
1125 PM EDT Thu Apr 10 2025
.SYNOPSIS...
A deepening upper level trough will close off over the Ohio
Valley tonight, then pass south of Pennsylvania Friday night
into Saturday. High pressure will build into the region Sunday,
then a cold front is likely to sweep southeast across the area
Monday night.
&&
.NEAR TERM /UNTIL 7 AM FRIDAY MORNING/...
Late evening water vapor loop shows a potent shortwave lifting
northeast over KERI. An area of steady rain along the attendant
low level jet is exiting the southeast part of the forecast area
at 03Z. Scattered showers have formed ahead of a weak mid level
vort max over the Central Mtns. Latest RAP indicates this
feature and associated showers will shift east, exiting the
eastern edge of the forecast area by around 07Z. Otherwise, a
moist southeast flow off of the Atlantic should result in
lingering drizzle and ridgetop fog overnight, especially where
the southeast flow is forced to ascend the higher terrain of the
Alleghenies.
Model soundings will remain marginally cold enough to support
a wet snow/rain mix tonight over the high terrain of Sullivan
County, but latest surface temps suggest any light
accumulations of <0.5 inch should be confined elevations above
2250ft.
Dewpoint depressions are quite low this evening, so expect
little drop in temperatures overnight with daybreak readings
likely ranging from the mid 30s over the Mtns north of KIPT, to
the low 40s over the southern counties.
&&
.SHORT TERM /7 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
The combination of high pressure over the Canadian Maritimes and
a weak surface low tracking along the VA/NC border will result
in a persistent, moist easterly flow off of the Atlantic through
Friday, resulting in low clouds and areas of drizzle over
Central PA. However, a period of more substantial rain appears
likely late Friday into Friday night over the southeast part of
the forecast area associated increasing forcing ahead of the
upper trough, which is progged to close off over Virginia.
A decent plume of Atlantic moisture, combined fgen forcing on
the northwest periphery of the associated surface low, should
produce the most significant rain south and east of Harrisburg
late Friday into Friday night. Latest EPS suggests 0.5 to 0.75
inches is likely over Lancaster County, while the higher
resolution HREF indicates localized totals >1 inch are possible
in this area. Much lighter rain/drizzle is anticipated over the
western half of the forecast area Friday/Friday night, with
totals generally <0.10 inches.
Cold air damming, combined with low clouds and rain, should
result in a very chilly Friday by mid April standards with highs
in the 40s.
A drier Saturday is expected, as the surface low passes off the
Mid Atlantic coast, causing the flow to back to northerly over
PA. However, lingering showers are expected associated with
cold conveyor belt/TROWAL on the northwest periphery of the
closed upper low. 18Z EPS prob charts suggest any additional
rain Saturday will be <0.10 inches and focused over the eastern
half of the forecast area. Cooler and dry weather is expected
Sat night, as weak high pressure builds in from the Ohio Valley
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Fair and seasonable weather looks likely Sunday, as the closed
upper low pushes off the East Coast and surface high pressure
builds in from the west. A return southwest flow between the
exiting surface high and an approaching cold front over the Grt
Lks should result in a warm Monday with maxtemps several degrees
above climo.
The fast-moving cold front is progged to sweep across central
PA Monday afternoon/evening, accompanied by a round of showers
for most of the area. Strong large scale forcing and decent
moisture return support high POPs but relatively low QPF per
the latest EPS plumes (ensemble mean qpf 0.1-0.4 inches)
A digging upper trough over the E Grt Lks will then likely be
accompanied by blustery conditions into midweek with
temperatures falling well below mid April normals by Wednesday.
The arriving airmass should be sufficiently cold to produce lake
effect rain and snow showers over primarily the Allegheny
Plateau into early Wed.
Fair and seasonable weather looks likely next Thursday, as the
deep upper trough lifts out and surface ridging arrives.
However, an approaching warm front could potentially spread
showers into the region by Thursday night.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Ceilings ranging from IFR over the Nrn Mtns (BFD/JST/AOO),
MVFR in the central valleys and Laurel Highlands (JST/UNV to
VFR across the Susquehanna Valley) will lower overnight with
most or all airfields in the IFR Category by shortly after
midnight. Vsby- wise, most valley airfields will stay in the
MVFR range, while KBFD and KJST should dip into the lower end of
IFR or LIFR before daybreak Friday before rebounding into
higher end IFR or MVFR by late Fri morning.
Marginal LLWS will occur at most airfields into this evening
before winds aloft decrease by 10 kts or more.
Mainly IFR to low end MVFR CIGS persist through all of Friday
with MVFR VSBYS for much of the time.
Outlook...
Fri-Sat...Periods of rain with sub-VFR likely.
Sun...Improving conditions/trending VFR.
Mon...VFR. Clear early. Increasing clouds late.
Tue...Sct rain throughout the day. Sub-VFR possible.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Fitzgerald
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald
LONG TERM...DeVoir/Fitzgerald
AVIATION...Lambert/Gartner
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
623 PM CDT Thu Apr 10 2025
.KEY MESSAGES...
- Scattered showers and thunderstorms this afternoon will pose a
level 1 of 5, marginal, risk for severe weather from gusty
winds and hail, mainly south of the I-70 corridor.
- Patchy frost is expected Friday night, especially in rural
locations. Those with tender vegetation may need to cover their
plants tomorrow evening.
&&
.SHORT TERM... (Through Late Friday Night)
Issued at 243 PM CDT Thu Apr 10 2025
Latest MRMRs imagery shows scattered showers and storms drifting
across eastern MO/southwest IL this afternoon. SPC`s mesoanalysis
reveals 500-1000 J/kg MLCAPE, which coupled with 25-35 kt (highest
south) 0-6km bulk shear should be sufficient to sustain those storms
through the afternoon. Cold temps aloft have resulted in steep mid
level lapse rates, 8-8.5C/km between 500 and 700mb, which is
fostering frequent lightning and small to locally severe hail with
the feistiest cells. In addition, steep low level lapse rates and
seasonably dry low levels due to deep mixing in the wake of the
surface cold front are fostering optimal conditions for
evaporational cooling beneath cloud bases, which has promoted gusty
winds beneath these storms. There remains a level 1 of 5, marginal,
risk for severe weather from both wind and hail through the evening,
especially south and east of the St. Louis Metro/I-70.
While HREF mean brings 500mb temps to -26 degC (below the 10th
percentile for raobs launched from ILX for April 11th) over St.
Louis tonight, surface temps should hold in the 40s due to prolific
cloud cover. That same lingering cloud cover, combined with
continued cool advection in the wake of the gradually eastward
shifting upper trough, will result in daytime temperatures running 10-
15 degrees below normal for mid April with forecast highs in the mid
to upper 50s. Temperatures should sink like a rock with the loss of
cloud cover and weak to calm winds tomorrow night. Forecast lows in
the mid 30s suggests some frost which could pose a risk to tender,
newly emerged vegetation; while dewpoints should hover in the low to
mid 30s in the St. Louis Metro and places further west, NBM suggests
a 20-40% chance for a freeze in rural southwest IL where the HRRR
brings some sub 30 degF dewpoints in from the north by 12z/7am CDT
Saturday.
Bumgardner
&&
.LONG TERM... (Saturday through Next Thursday)
Issued at 243 PM CDT Thu Apr 10 2025
Cluster analysis suggests ensemble agreement in a ridge of high
pressure building into the region from the west Saturday into
Sunday, warming 850 mb temperatures to 14-18 degC by early Sunday.
High temperatures will begin to rebound on Saturday, but the more
pronounced warming won`t be felt until Sunday when highs are slated
to reach the 70s area-wide with locations west of a Steelville to
Madison line having a 40-60% chance of exceeding 80. As is often the
case this time of year, the surface pressure gradient will tighten
and consequently stiff south winds will ensue on Sunday with gusts
slated to reach 30-40 mph.
While models are not in agreement on precise time of arrival, a cold
front is slated to bring some chance for showers and thunderstorms
at some point Sunday night into Monday. At this point, forcing along
the cold front seems like it`ll be strongest to our north, in closer
proximity to the upper trough. This will result in lower chances for
severe weather in our neck of the woods, though the Low Resolution
Ensemble Forecast (LREF) system suggests a 40-50% joint probability
of sfc-500mb bulk shear > 30 kt and > 500 J/kg MUCAPE Sunday night
into early Monday, suggesting the risk is nonzero. Conditions turn
seasonably cool and rain chances abate behind that front favoring
a dry period Monday night through Tuesday, but significant model
variability becomes apparent in the LREF/NBM by mid next work
week.
Bumgardner
&&
.AVIATION... (For the 00z TAFs through 00z Friday Evening)
Issued at 616 PM CDT Thu Apr 10 2025
Thunderstorms will continue to weaken and fade from northwest to
southeast through 02z this evening. A few isolated showers will be
possible overnight, mainly between 08z-12z with little if any
impact. Therefore, any mention of showers was not included in the
prevailing groups overnight. Low level moisture allows ceilings to
lower to MVFR overnight into Friday morning, which is expected to
lift back to VFR late Friday morning into Friday afternoon.
Maples
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Marquette MI
1159 PM EDT Thu Apr 10 2025
.KEY MESSAGES...
- High pressure dominates the forecast the rest of the work week and
into the weekend with dry and quiet weather expected.
- Low pressure moving towards the Great Lakes will bring in our next
chances for rain Sunday into Monday followed by lingering lake
effect snow showers.
- Rising temperatures are expected into the weekend with daytime
highs reaching the 50s on Friday and low-60s Saturday/Sunday.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 1203 PM EDT Thu Apr 10 2025
RAP analysis shows troughing aloft directly over the region moving
to the east with a ridge axis from the Dakotas extending northeast
to Manitoba and northern Ontario filling in the wake of the trough.
This negative vorticity advection is leading to subsidence and thus
a gradual clearing of skies over especially over the north-central
UP, the Keweenaw, and the far-eastern UP per GOES-East imagery. The
resulting surface high pressure in the 1020s mb will remain over the
region through the short-term forecast. The HREF shows about 20%
chances of some cells of light precipitation popping up, but any
precipitation will have to overcome dry surface air as RHs are
forecast to fall to the 50% range this afternoon. Additionally, with
sub-10 kt flow up to about 8kft today, not much organization can be
expected. Have elected to go dry with this forecast, but if anything
does pop up, no impacts are expected.
Overnight tonight, under high pressure of over 1025mb (06Z GEFS) and
scattered or less cloud cover, temperatures falling to the dew point
and light winds (below 3 kt in most places) will provide favorable
conditions for patchy fog formation. The 12Z HREF shows 30-70%
chances of visibility falling below 1 mile north and west of a line
from Marquette to Iron Mountain and along/north of M-94/M-28 east of
US-41, with chances elsewhere around 20%. The Euro ensemble is a bit
less widespread, confining FG to the Keweenaw Peninsula. GLAMP
probabilities of lowered visibility and cloud ceilings are
increasing over the past 5 runs at Ironwood, though remain pretty
steady at around 25% at Houghton and Marquette. For now, this
forecast issuance will reflect patchy fog, though if upward trends
continue, a reactionary dense fog advisory would not be out of the
question.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 259 PM EDT Thu Apr 10 2025
High pressure over the Great Lakes will keep things dry Friday into
Saturday, with a warmer airmass working in seeing highs well into
the 50s and even the lower 60s Saturday afternoon.
Our next chances for precipitation could arrive as early as late
Saturday night with an initial shortwave moving south of Hudson Bay,
but chances increase into Sunday as a low pressure system ejects out
of the Rockies, with strengthening isentropic ascent ahead of this
on the nose of a LLJ. At the same time, a Clipper wave will be
moving out of the Canadian Prairies, and should eventually phase
with the more southern system sometime late Sunday into Monday. Will
note that, though there is still spread in the exact track, ensemble
and deterministic guidance is continuing to trend more southward
with this phasing system (perhaps owing to the flattening of the
ridge with that initial wave moving through?). This is leading to
better chances for precipitation across the UP Sunday before a dry
slot moves in late in the day. Whatever does fall is expected to be
a quick round of light rain, with 850mb temperatures as high as 5-8C
by Sunday morning.
Colder air working in behind the system may touch off some lake
effect rain/snow showers into Tuesday across the NW wind snow belts.
Will note that ensembles are pointing to around a 30-4% chance of at
least 3in of snow by Tuesday morning. Gusty winds are looking more
likely Monday and Tuesday given the strong pressure gradient over
the region, which is followed by strong pressure rises and cold air
advection behind the departing low. Quiet conditions are likely into
the midweek period as height rises build behind the departing trough.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 1159 PM EDT Thu Apr 10 2025
VFR conditions to initially prevail early, but fog potential will
become an impact through the course of the morning. Confidence is
high enough to trend toward IFR at IWD in the Fri 08-12Z time frame.
But, will lean toward MVFR at both CMX and SAW where dew point
depressions are larger. A return to VFR is expected not long after
sunrise. Winds will be light and not an impact.
&&
.MARINE...
Issued at 259 PM EDT Thu Apr 10 2025
Under primarily high pressure, winds will remain light and variable
the remainder of the work week through Saturday. As a low pressure
system heads towards the Great Lakes Sunday, SE winds increase to
around 20kts across the eastern half of the lake. Winds continue to
pick up on the back side of the departing system early next week.
Ensemble guidance suggests Gale potential across the central lake
increasing to 30-50% chance by Monday evening, then increasing
further to 70-90% behind the departing system Tuesday morning.
However, the track and strength of the low pressure center is still
quite uncertain.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...GS
LONG TERM...LC
AVIATION...TDUD
MARINE...LC
Area Forecast Discussion
National Weather Service Phoenix AZ
447 PM MST Thu Apr 10 2025
.UPDATE...Updated Aviation Discussion.
&&
.SYNOPSIS...
Unseasonably hot temperatures will persist across the
region through Saturday as strong high pressure prevails with many
of the lower desert locations likely to reach the triple digits
for afternoon highs. As a weather system passes well to our north,
winds will increase this weekend leading to elevated to locally
critical fire weather conditions. Cooler temperatures, but still
remaining above normal, can be expected late this weekend through
next week.
&&
.DISCUSSION...
The latest RAP analysis shows a strong ridge of high pressure
enveloped across the Desert Southwest with 500 mb height fields
exceeding 588dm. As a result, unseasonably hot temperatures that
are a good 15 degrees above normal will prevail through Saturday.
Many of the lower desert locations are likely to reach or even
exceed 100 degrees, with Friday being the peak in the
temperatures. Temperatures of this magnitude will likely
tie/exceed record highs at all of the three major climate sites
(Phoenix, Yuma, El Centro). Given these anomalously hot
temperatures in place through the next couple of days, the overall
HeatRisk will be in the moderate category. Therefore, for those
partaking in outdoor activities, the necessary heat safety
measures should be taken.
As we head towards the weekend, a shortwave trough passing
through the Pacific Northwest and northern Rockies will cause the
ridge to shift east, lowering the heights aloft and promote a
cooling trend starting on Sunday as high temperatures fall back
into the lower to middle 90s. In addition to the cooling
temperatures, the shortwave trough will create enough of a
pressure gradient to result in enhanced breeziness both Saturday
and Sunday with peak afternoon gusts of 20 to 30 mph across most
of the region, with locally higher gusts in excess of 30 mph
across the higher terrain areas east of Phoenix. The combination
of the elevated winds and very dry conditions will result in
elevated to locally critical fire conditions. As a result, in
coordination with the Tucson office, a fire weather watch for
critical conditions has been issued for both Saturday and Sunday
across the higher terrain areas east of Phoenix where the
probability of seeing winds reaching/exceeding 30 mph will be the
greatest.
Heading into next week, the ensemble guidance shows another ridge
building across most of the western CONUS. However, at the same
time, the guidance is also showing a couple of shortwave troughs
over the eastern Pacific undercutting the ridge that will likely
move over the Desert Southwest. The first shortwave will likely
move over the region late Monday into Tuesday with a follow on
shortwave moving in towards the latter half of the week. Both of
these systems will likely produce some enhanced breeziness as
well as keep any abnormal heat in check. The latest NBM shows
temperatures for most of next week fluctuating between the low to
mid 90s across the lower deserts.
&&
.AVIATION...Updated at 2348Z.
South Central Arizona including KPHX, KIWA, KSDL, and KDVT; and
Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation weather concerns are anticipated through the TAF
period. Winds will favor light, diurnal tendencies with speeds
generally under 10 kts and periods of variability throughout the
TAF cycle. Mostly clear skies will persist with some passing high
clouds.
&&
.FIRE WEATHER...
Abnormally hot conditions with temperatures across many of the
lower desert locations reaching into the triple digits can be
expected through the start of the weekend. A cooling trend is
expected by the end of the weekend through next week, however,
temperatures will still remain above normal. MinRHs through the
next several days for most of the area will remain in the single
digits with poor overnight recoveries. Winds through Friday will
remain light and follow the typical diurnal trends, with some
occasional afternoon upslope breeziness. By the weekend, as a
weather system passes to the north, winds are expected to increase
across the region with widespread afternoon/early evening peak gusts
between 20-30 mph, with locally higher gusts in excess of 30 mph
across the eastern districts. The combination of the gusty winds
and very dry conditions will result in elevated to locally
critical fire conditions. A couple of additional weather systems
will likely affect the region next week resulting in enhanced
breeziness and thus more elevated fire weather concerns.
&&
.CLIMATE...
Record high temperatures this week:
Date Phoenix Yuma El Centro
---- ------- ---- ---------
Apr 10 100 in 2018 100 in 1960 98 in 2018
Apr 11 99 in 2023 101 in 1936 100 in 2018
Apr 12 99 in 1936 102 in 1962 103 in 1940
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Fire Weather Watch from Saturday morning through Saturday
evening for AZZ133.
Fire Weather Watch from Sunday morning through Sunday evening
for AZZ133.
CA...None.
&&
$$
DISCUSSION...Lojero
AVIATION...Smith
FIRE WEATHER...Lojero
CLIMATE...Kuhlman
Area Forecast Discussion
National Weather Service Raleigh NC
840 PM EDT Thu Apr 10 2025
.SYNOPSIS...
Deep and strong low pressure will move eastward across the Carolinas
and Virginia tonight through Saturday. This low will push slowly
eastward off the East Coast of the United States Saturday night
through Sunday.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 840 PM Thursday...
Forecast update this evening primarily dealt with timing of precip
chances and spatial tweaks. The broad band of showers now pushing
through the heart of central NC and aligned with a mid level
shortwave will continue pushing E, and with no CAPE to work with, no
lightning is expected. However, we may see some storms later
tonight, mainly over our southern tier, as the large broken arc of
deeper convection from W NC through Upstate SC and N GA/AL pushes
ESE close on the heels of the current band of showers, supported by
greater height falls as the second deeper mid level shortwave trough
approaches. Most of the recent HRRR/RAP runs hold this convection
largely S of Hwy 64, reasonable based on the current pace, so have
trimmed back pops a bit across the north overnight. Overall, with an
inhospitable environment over much of central NC overnight,
including a slight decrease in mid level lapse rates and just a
couple hundred J/kg of SBCAPE at most across our far S, no severe
weather is expected overnight, although the far S tier could see
some gusty winds in and near the northern edge of the convection.
Expect overcast skies overnight, with thick low clouds and areas of
fog through daybreak. Lows in the upper 40s to lower 50s with light
winds. -GIH
Previous discussion from 400 PM: A broad surface low currently
extends across the TN and OH Valleys, as ridging from a high
pressure system centered east of New England extends SW down the
Eastern Seaboard. As the low moves east tonight and approaches
central NC by early Friday morning, the ridging will exit to the NE.
Looking aloft, around the base of a broad mid/upper trough currently
over the Central and Eastern US, water vapor imagery depicts a lead
shortwave diving into the southern Appalachians. Mid-level height
falls of 6 dam in 12 hours will result ahead of the wave. This has
produced a line of showers that is moving east and currently
entering the NW Piedmont. This line will move across central NC from
now through about 05z, gradually weakening as it does so. Went with
likely to categorical POPs with this line. Despite decent cooling
aloft and mid-level lapse rates of 6.5-7 deg C per km depicted on
SPC mesoanalysis, the limiting factor for any storms will be
instability, as there is a lack of low-level moisture across the
region, with surface dew points only in the 40s. Furthermore, there
is a fair amount of cloud cover, with most places reporting broken
if not overcast skies, which is limiting surface heating. So very
little CAPE is expected ahead of the line, on the order of 100-200
J/kg according to the latest HRRR and RAP. Current GLM imagery and
observations don`t depict any lightning with the line at this time.
SPC does clip our far western Piedmont in a marginal (level 1 of 5)
severe threat, but while isolated thunder will be possible, think
any severe weather is unlikely. Still, can`t rule out a brief wind
gust of 30-40 mph as the line moves through. Temperatures are
reaching the mid-60s to lower-70s this afternoon, which is slightly
below average.
Additional scattered showers are also expected overnight tonight
amid the large-scale ascent and mid-level height falls, as
additional mid-level perturbations rotate around the base of a
second more potent shortwave. This wave will pivot over the southern
Appalachians by Friday morning. Isolated thunder can`t be ruled out
either as temperatures aloft continue to cool, but MUCAPE will still
be limited. Total rainfall amounts through 12z Friday are expected
to be a quarter to half an inch on average. Tonight`s lows will be
much more mild than previous nights with the widespread cloud cover,
in the upper-40s to lower-50s.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 325 PM Thursday...
* Marginal Risk of Severe Storms, with the primary threat of hail
* Marginal Risk of Excessive Rain, with main flash flood threat in
urban areas
A deep trough with a shortwave located over the southern
Appalachians will track ENE over NC/VA during the afternoon and
evening before moving into Delmarva overnight and Saturday morning.
At the surface, while guidance still is mixed on the exact location
and track of the low, a general consensus is that the system will
track from near Charlotte to western NC in the morning and overtop
central NC in the afternoon to early evening, before moving offshore
NC/VA Fri night to Sat morning.
Confidence is increasing on two main waves of showers and storms for
Fri. The first wave appears to come through in the morning hours
from the south and west in response to deep upper-level forcing from
the trough combined with low-level moisture transport along/north of
a warm front. Elevated instability with this first wave will favor
isolated storms during the morning, especially across the Coastal
Plain. A second round of scattered showers and storms is expected to
then develop in the afternoon to early evening as the upper-low and
low track across the region during peak heating.
Looking at the 12z HREF, the individual members still disagree on
specifics, but show the general trend discussed above. The main
severe threat appears between about 11 am and 7 pm based on the HRRR
neural network from NCAR, with the greatest risk between 2 and 6 pm.
Some late-morning to early afternoon convection over the Coastal
Plain aided by elevated instability amid steep lapse rates and along
the warm front will favor our first risk of hail. The afternoon to
early evening period remains somewhat uncertain. As the upper-low
tracks east, a dry slot may work in from the west. This along with
questions on the degree of destabilization from morning convection
has kept our uncertainty in this time frame. Nevertheless, the
favorable deep layer shear of 40-50 kts combined with very steep mid-
level lapse rates will continue to support a large hail risk, with a
secondary wind threat.
The SPC afternoon update included a low-end tornado risk over the
Triangle to Coastal Plain. Some guidance suggests a stronger,
wrapped-up low could form as it tracks across central NC. If this
were to happen, it could favor stronger low-level shear for this
tornado threat. But confidence on this scenario is low at the moment.
Highs should top out close to 60 in the north and low 70s in the
south. As the low tracks eastward Fri night, we should see coverage
of showers/storms lessening, holding on to mainly low-end shower
chances in the NE zones after midnight. Cold advection behind the
low and passing cold front will bring low temperatures into the low
40s NW to upper 40s SE.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
As of 235 PM Thursday...
While the late week surface low will have moved offshore by Saturday
morning, the accompanying upper low will still be over eastern
Virginia and will slowly drift offshore Saturday and Saturday night.
Models show a thick layer of saturated low-level air through the day
and while the GFS is a dry outlier, the NAM/ECMWF/SREF/GEFS/EPS all
show isolated to scattered showers during the day. Slightly
increased pops during this time period, but think that conditions
should dry out Saturday night. High pressure will extend over the
Ohio River Valley Sunday, moving southeast of the Carolinas by
Monday. One cold front should arrive Tuesday morning, and while the
GFS/ECMWF keep the bulk of precipitation offshore as the front moves
through, the GEFS/EPS both show some probability of showers across
eastern counties. Made no change to the inherited forecast for
showers Tuesday afternoon. Another cold front moves across the
region Wednesday, but deterministic/ensemble models are in agreement
that there should not be enough moisture for showers with the second
front. Yet another system will approach from the west on Thursday,
but it appears that any measurable precipitation should hold off
until Thursday night.
Temperatures continue to trend cooler on Saturday as the cloud cover
looks to be thicker than previously forecast. Blended in some 25th
percentile of the NBM, which does a good job emphasizing the
gradient from northeast to southwest. At this rate, wouldn`t be
surprised to eventually see a forecast that doesn`t get some
locations out of the 40s on Saturday, but for now, the range is from
52 to 62 degrees. Temperatures moderate on Sunday, but remain below
normal, before rising above normal Monday and Tuesday then returning
to near normal for Wednesday and Thursday. The coolest overnight
lows will be Saturday and Wednesday nights, but with the coldest
locations only dropping into the upper 30s, there are no
frost/freeze concerns.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
As of 750 PM Thursday...
A line of showers is currently working its way eastward across
central NC, moving through RDU currently, and expected to reach FAY
and RWI by 01z and 02z respectively. Main concerns as it passes will
be a wind shift out of the WNW 15 to 25 kts, and vsby 2 to 4 SM. A
rumble of thunder is certainly possible, but thus far has not
occurred.
After the passage of this lead band of showers, aviation conditions
will steadily deteriorate. Shallow showers will be possible ahead of
a line of more organized convection as it moves from upstate SC into
the NC Sandhills (potentially affecting FAY and RDU between 06z and
09z). At the same time, cigs are expected to thicken/lower to IFR;
greatest chances at GSO/INT with less confidence at FAY. Cigs may
fall close to landing minimums at GSO/INT and result in vsby
restrictions as well. Improving conditions to MVFR and perhaps VFR
in spots will be slow Fri morning with showers and storms possible
during the afternoon/evening. Some may be strong to severe;
confidence is low on direct terminal restrictions at this time.
Outlook: MVFR cigs and some shallow showers are expected to linger
Fri night through Sat, especially at RWI and potentially at RDU/FAY.
A return to VFR is expected Sat night. Gusty southwesterly winds 20
to 30 kts and low-level turbulence will be possible on Mon ahead of
dry cold frontal passage on Tues.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Hartfield
NEAR TERM...Hartfield/Danco
SHORT TERM...Kren
LONG TERM...Green
AVIATION...Swiggett