Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/17/24
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
630 PM CDT Thu May 16 2024
.KEY MESSAGES...
- A weak disturbance will bring a 20 to 30 percent chance for
showers and thunderstorms to mainly the northern half of South
Dakota this afternoon and evening. Gusty winds over 40 mph
possible with any stronger cells.
- Above average temperatures can be expected on Friday with highs
in the 80s. A few locations may reach 90 degrees.
- A frontal boundary crossing the area late Friday afternoon and
Friday night will be the focus for a 40 to 70 percent chance
(northern SD) for thunderstorms. Some may be severe across parts
of central South Dakota, with gusty winds around 60 mph the
main threat.
- Strong west to northwest wind gusts between 30-45mph will be
possible on Saturday. Highest probabilities for the strongest
gusts are across our northern tier of counties along the ND
border.
&&
.UPDATE...
Issued at 628 PM CDT Thu May 16 2024
Made some hourly tweaks to pops based on latest radar trends.
Isolated to scattered thunderstorms will continue to move east
across the northern cwa this evening.
&&
.SHORT TERM /THIS EVENING THROUGH FRIDAY NIGHT/...
Issued at 339 PM CDT Thu May 16 2024
Weak disturbance aloft passing across the Dakotas while at the
surface, a boundary/wind shift is noted across western SD. We`ve
seen a cumulus field develop across central SD over the past couple
hours, with a couple towering/agitated areas across Corson/Dewey
counties. We do have two weak cells showing up on radar (as of 3PM),
with weak instability (500-1000 J/KG MLCAPE) and shear (~25kt 0-6km)
in place. Mid-level lapse rates are modest, around 7 C/km. Latest
HRRR runs do continue to show widely scattered activity across
central SD over the next couple hours, and has taken a noticeable
shift southward with potential activity, something to watch as
current precip chances do not quite go that far south. Had already
earlier this afternoon added 20% chances to north central SD as the
cumulus field was growing and HRRR starting hinting at possible
development. Previous forecast did not have things going until later
in the afternoon and closer to 00Z. Really don`t expect things to
get out of hand, as severe parameters stay mostly in check through
the evening, but would not be surprised to get some gusty winds over
40 mph with any stronger cores that develop.
As we head into Friday, will be watching the arrival of a cold front
into the western Dakotas by late afternoon/evening. Better upper
level support as well, with only modest low-level moisture return.
The strong cold front will provide good lift for convection though,
and CAMs continue to show development reaching the western CWA
around 00Z. Severe parameters show mostly a wind threat with any
storms that move into central SD Friday evening, with steep lapse
rates developing in a deeply mixed environment. Marginal risk (level
1 out of 5) continues to be in place across central SD as the front
makes its way through the region during the evening hours.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 339 PM CDT Thu May 16 2024
This period will begin Saturday morning with a cold front departing
east of our forecast area while sfc high pressure shifts south and
east out of the Rockies and Northern High Plains toward Nebraska and
Kansas during the day. Cooler and drier conditions will be setting
in for the first half of the weekend. In addition, much stronger
winds out of the west-northwest are expected on Saturday. With a
tight pressure gradient in place, strong wind gusts in excess of 40
mph will be possible for some of our forecast zones. In fact, the EC
ensemble data suggests the probabilities of wind gusts exceeding 40
mph is highest(40-50 percent) from north central SD eastward along
our northern tier of counties along the ND border into the James
Valley. NBM probabilities of gusts exceeding 40 mph are higher in
these same locales on the order of a 70-95 percent range. So, this
lends some confidence that windy conditions will be the feature of
the day on Saturday. At this point, we would anticipate wind gusts
will be somewhere in the range of 30-45mph. We`ll have to watch
trends over the next 24 hrs to see if a wind headline would be
warranted.
An unsettled pattern returns by early next week. A reinforcing mid
level trough will shift into the western CONUS maintaining
southwesterly flow aloft across our region. Deterministic and
ensemble solutions prog a disturbance to shift northeast into parts
of the Central and Northern Plains on Sunday into Monday. Shower and
thunderstorm chances will be on the upswing Sunday into Sunday
night. The western CONUS upper trough is progged by guidance to
shift into the north central CONUS by the middle of next week. This
will maintain our unsettled weather with more on again, off again
chances for showers and storms through the end of the period.
Temperature trends through this period should maintain near normal
to slightly above normal values with overnight lows in the 40s and
50s and daytime highs in the 60s and 70s.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 628 PM CDT Thu May 16 2024
Terminals KABR,KATY,KPIR,KMBG
VFR conditions are expected through Friday afternoon except in the
vicinity of heavier thunderstorms.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Wise
SHORT TERM...TMT
LONG TERM...Vipond
AVIATION...Wise
Area Forecast Discussion
National Weather Service Amarillo TX
710 PM CDT Thu May 16 2024
...New AVIATION...
.SHORT TERM ...
(This evening through Friday night)
Issued at 234 PM CDT Thu May 16 2024
Looking at current GOES-16 water vapor imagery an mid to upper
level pressure is centered right around the White Sands and
Mescalero Reservation in south central New Mexico. The associated
trough with this system as already brought some showers and
thunderstorms to the southwestern Texas Panhandle southward
towards Muleshoe. Showers and thunderstorms will continue to be
possible early this afternoon for the southwest and possibly
western TX Panhandle. However, it will not be until later this
evening when the aforementioned low pressure system moves into
portions of West Texas and the southern TX Panhandle when the
southern portions of the FA can see some slightly higher chances
for rain again.
Currently there is some decent bulk shear around 30 to 35 kts
based on this mornings KAMA upper air sounding. However, there was
a measly 45 J/Kg of MLCAPE with a very stout cap. Late this
afternoon as the cap weakens and MLCAPE is progged to jump to
around 800 to 1000 J/Kg of for spread across the southern TX
Panhandle. However, some low clouds have been playing a role in
overall heating today and bulk shear is progged to fall to around
20 kts or less when the main system comes across. Severe storms
are not anticipated due to these factors, but cannot completely
rule out an isolated severe storm with one inch hail and 60 mph
plus wind gusts late this afternoon/evening.
Some of the CAMS are excited about storm activity as far north as
the I-40 corridor with others keeping all the activity to the
south. The track of the upper level low and the main dynamics from
it will determine how much of the FA actually gets the showers and
thunderstorms. If the NAM is correct, there will be quiet a bit of
negative H7 theta-e advection for much of the northern half to two
thirds of the combined Panhandles. This will limit any activity to
south of the I-40 corridor and may even kill any chance for
Amarillo to see some moisture. The RAP solution favors areas north
and south of I-40 in southern TX Panhandle, to include much of
Oldham to Wheeler County north of the Interstate. Mainly between 4
PM and 10 PM this evening.
With the upper level low tracking across during the late afternoon
and evening hours, it should start to exit taking all precip
chances with it before 11 PM. This will leave the FA in the wake
of the trough and meridional flow aloft ahead of a ridge building
into the area. Because of this Fri is looking dry with daytime
temperatures rebounding into the lower 80s. Surface winds are
progged to be light and variable through the afternoon with a
pleasant day in store.
36
&&
.LONG TERM ...
(Saturday through next Wednesday)
Issued at 234 PM CDT Thu May 16 2024
Winds aloft Saturday quickly go from northwest to westerly as an
upper level ridge builds into the area. With this ridge H85
daytime temperatures begin to rise to near 27 degrees C, with
surface temps expected to be in the upper 80s and lower 90s for
Sat afternoon. This ridge continues to build with Sun and Mon
being the warmest with wide spread temps in the mid 90s across the
combined Panhandles. Palo Duro Canyon may even flirt with its
first triple digit day of the year with mostly clear skies.
Although it is looking like it will be dry during this time. The
GFS shows an upper shortwave passage, a perturbation in the ridge
aloft potentially sparking some thunderstorms over portions of the
north and eastern combined Panhandles. At the surface the models
suggest a potential dryline in the eastern Panhandles in the
afternoon. Have stuck with the NBM PoPs which leaves all areas dry
with the dryline mixing well east by the time any thunderstorms
can get going. Will need to keep an eye on the model trends
through the weekend to see if models trend differently with the
dryline and thunder potential.
Late Mon into Tue morning an upper level shortwave is progged to
approach the combined Panhandles. This will send a weak cold front
into the area for Tue and Wed cooling afternoon temps off a bit
back into the upper 70s to the northwest and 80s to the southeast
for Tuesday, and widespread lower 80s on Wed. At this time the
trough does not appear to bring any precip chances to the combined
Panhandles, but it does to areas just north of the OK Panhandle.
36
&&
.AVIATION...
(00Z TAFS)
Issued at 646 PM CDT Thu May 16 2024
For the 00Z TAFS, any showers or thunderstorms that are scattered
around the area should not impact the terminal sites this evening
before dissipating near or shortly after sunset. Otherwise, VFR
conditions are expected to prevail at KGUY, KDHT, and KAMA through
late Friday afternoon.
02
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 51 80 53 90 / 30 0 0 0
Beaver OK 51 83 52 92 / 10 0 0 0
Boise City OK 46 82 50 87 / 10 0 0 0
Borger TX 53 84 56 94 / 20 0 0 0
Boys Ranch TX 50 83 53 93 / 20 0 0 0
Canyon TX 51 80 50 91 / 40 10 0 0
Clarendon TX 54 79 55 89 / 50 10 0 0
Dalhart TX 46 81 46 89 / 20 0 0 0
Guymon OK 49 83 51 89 / 10 0 0 0
Hereford TX 51 81 50 93 / 50 0 0 0
Lipscomb TX 53 82 55 91 / 10 0 0 0
Pampa TX 52 81 55 89 / 30 0 0 0
Shamrock TX 55 80 56 89 / 50 10 0 0
Wellington TX 56 80 55 89 / 60 10 0 0
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...None.
OK...None.
&&
$$
SHORT TERM...36
LONG TERM....36
AVIATION...02
Area Forecast Discussion
National Weather Service Indianapolis IN
937 PM EDT Thu May 16 2024
.KEY MESSAGES...
- Patchy fog in the NW possible again tonight.
- Rain and storm chances return at times late this evening through
Saturday.
- Above normal temperatures this weekend through the middle of next
week.
- Increasing threat for strong to severe storms by Tuesday and
Wednesday next week.
&&
.FORECAST UPDATE...
Issued at 935 PM EDT Thu May 16 2024
- Rain Chances continue overnight. Patchy Fog expected.
Surface analysis late this evening shows a weak, disorganized trough
of low pressure stretching from WI to OK. Southerly flow was in
place across Central Indiana ahead of this trough. GOES16 shows
abundant cloud cover across the area. This was mainly due to a large
tropical plume aloft stretching from the southern plains, across
Indiana to the eastern Great Lakes. This was continuing to result in
a warm and humid air mass across Central Indiana and dew point temps
were mainly in the 60s. Radar shows a few scattered showers across
western Central Indiana, pushing east.
Overnight the weak trough will make slow progress toward Central
Indiana. The warm and moist air mass and abundant cloud cover will
remain across Central Indiana. Forecast soundings keep lower levels
saturated through much of the night while HRRR suggests scattered
light rain showers moving across the state overnight. Thus will
continue to keep high chc pops as associated and timed with the main
area of precip over west central Indiana and keep lower pops
elsewhere. Dew point depression overnight once again fall to 1-2F,
but this time overhead clouds will be present as compared to last
night. This should allow for some patchy fog formation, but fog as
dense as the previous nights in outlying locations will not be
expected. Lows mainly in the lower 60s will be expected.
&&
.SHORT TERM (This evening through Friday)...
Issued at 258 PM EDT Thu May 16 2024
A broad trough is bringing rain to the region that will move into
the forecast area shortly. Radar at the moment shows areas of light
rain over Illinois with isolated stronger showers and the
potential to produce a few lightning strikes as it moves in. This
system is becoming more dispersed as it moves in.
Clouds and scattered showers will likely stick around for much of the
night tonight with model soundings showing persistent saturation at
the top of the boundary layer, but will have to keep an eye out for
any locations that do begin to clear as the recent rains will help
to supersaturate the low levels and may allow for some fog
formation, especially across northwest Indiana where rain to be less
in coverage. Further to the southeast, clouds and occasional rain
should help to limit the fog formation with less efficient
radiational cooling even as winds drop to near calm.
Rain chances continue though the day tomorrow for most of the area
and best chances across the southern half of the area. While
overnight the rain seems to shift slightly southward, it does look
as if it will retreat back into the north some during the day Friday
due to a relatively stationary boundary sits over the Ohio Valley.
Isolated lightning will continue to be a threat tomorrow.
Temperatures tonight will drop only to near 60 with warmer
temperatures expected tomorrow thanks to WAA. Highs tomorrow will
reach the mid to upper 70s.
&&
.LONG TERM (Friday night through Thursday)...
Issued at 258 PM EDT Thu May 16 2024
Friday night through Saturday...
Look for rain chances to remain in the forecast to start the
extended as a weak surface wave traverses the region. Sufficient
moisture and forcing should support scattered showers and possibly a
few storms Friday night. Models have become better aligned for
Saturday with the aforementioned system shifting east during the day
with upper ridging/weak surface high pressure building in late.
Sufficient moisture and overall forcing will likely still be in
place Saturday for precipitation, mainly during the afternoon hours
when better destabilization is expected from daytime heating.
Weak overall flow during this period should result in slow moving
showers/storms. This combined with saturated grounds from recent
rainfall raises some concern for flooding where highly localized
areas of heavier rain could occur. Confidence in this threat is low
though due to relatively weak overall forcing and guidance trending
towards weaker moisture return.
Saturday night through Monday...
Upper ridging and surface high pressure should provide mostly quiet
weather conditions. However, isolated convection cannot be ruled out
over far S/SE portions of central IN Sunday afternoon where
sufficient PBL moisture could still be in place during the
afternoon. Latest guidance has lowered confidence in this potential
since most models show deeper moisture pushing further southeast of
the area. Expect increasing heights aloft and low cloud cover to
help warm temperatures well into the 80s both Sunday and Monday.
Monday night onward...
Guidance is in general agreement that the upper level pattern will
switch to more full-latitude troughing across the western CONUS
compared to split flow this week. This should result in a more
active pattern with multiple embedded shortwaves potentially
tracking over the Midwest next week. Look for rain chances to begin
increasing Monday evening and remaining elevated through at least
midweek.
At least a low end severe weather threat looks possible Tuesday into
Wednesday as increasing instability and deep-layer shear ahead of an
approaching surface low/parent trough could support organized convection.
CIPS Analogs and CSU machine learning are showing increasing
severe weather probabilities during this period. It is still too
early for exact details, but this threat will be closely monitored
over the coming days. Temperatures look to remain above normal,
but cooler air is expected to filter in midweek behind a cold
front.
&&
.AVIATION (00Z TAF Issuance)...
Issued at 657 PM EDT Thu May 16 2024
Impacts:
- VFR becoming MVFR or worse overnight
- MVFR returning VFR after 18Z Fri.
- Scattered light rain showers much of the period.
Discussion:
Scattered light rain showers over IL are expected to push back
across Central Indiana this evening and overnight. Coverage is not
widespread, thus precipitation will be more of the hit and miss
variety and confidence for precise timing at any given location is
low. Thus VCSH was used.
Overnight, MVFR conditions are expected to return as forecast
soundings shows saturation within the lower levels. MVFR fog will
also be possible due to abundant residual lower level moisture,
However, fog should not be extensive as last night as cover cover
should prevent max cooling.
A frontal boundary near the Ohio river along with a passing upper
level disturbance will keep rain chances in play for much of Central
Indiana on Friday. Again, VCSH has been used due to low confidence
of precise timing and best forcing features being found south of the
TAF sites.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Puma
SHORT TERM...KF
LONG TERM...Melo
AVIATION...Puma
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
850 PM EDT Thu May 16 2024
.KEY MESSAGES...
- After a lull in shower and thunderstorm chances for most places
tonight, higher chances return to close out the week and carry
over into Saturday and Saturday evening, before tapering off
Saturday night into Sunday.
- High pressure brings dry weather back to the area Sunday night
through Tuesday. A couple areas of low pressure will bring rain
back to the area Tuesday night through Thursday.
- Near normal to slightly above normal temperatures are expected
to continue into the weekend. A further warm up is then
expected into the first part of next week.
&&
.UPDATE...
Issued at 840 PM EDT THU MAY 16 2024
Precipitation chances and sky cover were decreased for the
remainder of the evening into the start of the overnight hours
based on radar and satellite trends. The initial clearing, should
set the stage for fog development and or low clouds/stratus across
the south and southeast. Some of this may become dense in the
valleys overnight.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 415 PM EDT THU MAY 16 2024
The models exhibited some differences today regarding sensible
weather across eastern Kentucky the next few days. The system that
will influence our weather Friday into Saturday looks to be a
developing storm system that will move out of the southern Plains
Friday and Friday night, and then across the lower Mississippi
Valley and Tennessee Valley. A few rain showers were popping here
and there is a few of our eastern counties this afternoon, and it
appears this activity will continue until the sun begins to set
this evening. After that, we should see dry weather through the
night. With none of the models showing any convection continuing
after dark in our area, decided to keep things dry after 23Z. The
NAMNEST, NAM12, and HRRR models were the most robust with shower
and storm activity around eastern Kentucky tonight through
Saturday. The upper pattern currently features a warm front now
situated north of the Ohio River, which was previously seen as a
trigger for convection in our northwest counties this evening, but
with this boundary now being analyzed well out of our area, it
does not appear the front will play a factor in convective
activity in our area this evening.
The latest model consensus seems to be pointing toward having the
first showers and storms moving into our northwest very late
tonight to around dawn on Friday, with activity gradually
spreading eastward and increasing in coverage through out the day
on Friday. A new wrinkle in the latest model data is the
production of a large and robust MCS far to our south that will be
moving across the southern portions of the states along the Gulf
of Mexico. The models, to varying degrees, have this southern MCS
cutting off the northward moisture off of the Gulf, thereby
decreasing the coverage of showers and storms across KY and TN
Friday and Friday night. The latest SREF runs took this scenario
to the extreme, and had very little precip affecting eastern
Kentucky on Friday, with scattered activity occurring early Friday
morning, but quickly dissipating by around 16Z, and having not
much else occurring until later in the day in our northern
counties and keeping Saturday almost entirely dry. That being
said, the solutions of the NAMNEST and HRRR runs seemed more
reasonable, as a moist air mass is already in place, and we should
see enough moisture return to support scattered to at times
numerous showers and storms around our area heading into the
weekend.
Temperatures still look to be quite warm on Friday, perhaps a few
degrees above normal, with mild lows on tap tonight and Friday
night. Winds should see be fairly light heading into the weekend
as well. No major weather concerns at this time, but there is a
small chance of excessive rainfall occurring with some of the
storms on Friday, or where multiple storms move over the same
areas repeatedly.
.LONG TERM...(Saturday through Thursday)
Issued at 415 PM EDT THU MAY 16 2024
Models are indicating an upper level split flow expected across the
CONUS at the start of the period, with the southern portion of the
flow having troughiness from the ArkLaTex region northeastward over
the Ohio Valley. A weak upper low is expected to be embedded in this
trough, but there is poor model agreement on its position. Ample
moisture should be present beneath and ahead of the upper trough,
allowing for precip. The regime will shift east with time, but the
aforementioned model discrepancies result in uncertainty down the
line as to how quickly it departs. A model blend being used for the
forecast continues to lack details, but has an overall decreasing
POP trend during the weekend, overlaid with diurnal tendencies. Dry
weather is forecast by late Sunday evening. Ridging at all levels
approaching and passing over from late Sunday night through Tuesday
will result in dry weather persisting during that time. Slightly
drier low level air should also arrive.
Beyond this, a shortwave trough aloft originating in the northern
part of the flow is expected to approach and pass over Tuesday night
and Wednesday, with the bulk of the wave to our north. This supports
a surface cold front which both the GFS and ECMWF pass through our
area on Wednesday afternoon or evening. The best upper level support
is weakening and shifting to our north as the system goes by. It
would also appear that the best moisture return ahead of the front
will be to our west and probably not make it here before cold fropa.
These considerations as well as models only generating light precip
here, will limit the POP to chance category.
By Thursday, the deterministic/operational ECMWF has deepened an
upper level trough over Ontario and the eastern CONUS much more so
than the deterministic/operational GFS. In terms of surface features,
this allows the ECMWF to take the cold front further south than the
GFS. The GFS`s stalling of the front further north results in
additional precip in our area on Thursday, compared to a dry ECMWF.
The GFS ensemble mean points toward more eastern CONUS troughing
than in the operational/deterministic run, lending some support
toward the ECMWF idea. That being the case, will go with POPs a
little below the values in the model blend on Thursday, with nothing
higher than slight chance.&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 142 PM EDT THU MAY 16 2024
Based on current trends, the TAF sites will continue to experience
BKN low level cover through around 0Z this evening, before the
clouds begin to scatter out a bit. VFR should be the rule at JKL,
LOZ, and SME, but SJS and SYM will continue to see MVFR CIGs of
around 2K this afternoon, before the clouds scatter and lift a bit
this evening. Winds should be generally light and variable through
out the period, but especially tonight. Clouds will be on the
increase late tonight, as an area of low pressure moves in from
the west, leading to periods of BKN clouds. A few showers and
storms could begin moving into the I-64 corridor in our
northwestern counties late this evening. The rain will continue to
advance slowly eastward overnight into early Friday, and could
begin to affect JKL, LOZ ,SME, and SYM toward the end of the
forecast period. MVFR fog will be possible again tonight as
moisture advects in ahead of the incoming storm system. LOZ and
SME might even see brief periods of IFR fog between 10 and 12Z on
Friday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 835 PM EDT THU MAY 16 2024
Showers and cumulus were dissipating as of issuance time with VFR
reported areawide. The first 6 hours of the period, rain free
weather is expected, however, some upstream convection may begin
to move into the western and northwestern portion of the area
between 06Z and 12Z, with areas of convection spreading east and
southeast through the period as a disturbance and weakening
boundary work into the OH Valley. Some reductions into the MVFR
and IFR range are possible as the heavier showers or storms move
across the region generally after 18Z. However, areas of clearing
or a minimum in low and mid clouds are anticipated ahead of the
convection, and fog down into the MVFR range if not the IFR range
or perhaps lower are anticipated in the south and southeast.
VLIFR is possible at times between 06Z and 13Z in the deeper
valleys. KSME, KLOZ, KSJS, and KSYM could be affected by a few
hours of MVFR fog between 06Z and 13Z. Winds should be generally
light and variable through about 15Z, before becoming south to
southwest near 5KT to end the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...AR
LONG TERM...AR
AVIATION...JP
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
904 PM CDT Thu May 16 2024
.KEY MESSAGES...
- Patchy to areas of dense fog may develop overnight, especially
northwest of I-55.
- Summer-like warmth inland of Lake Michigan this weekend and
primarily dry, though can`t rule out an isolated afternoon
shower or thunderstorm (10-20% chance or less) either day.
- Active Monday-Tuesday: Scattered thunderstorms possible Monday
and waves of thunderstorms on Tuesday through Tuesday evening,
with an attendant threat for strong/severe storms and flooding.
&&
.UPDATE...
Issued at 851 PM CDT Thu May 16 2024
One lonesome thunderstorm managed to trek across a good portion
of the CWA this evening until just recently dying out over
Grundy County shortly after 8 PM. This storm was leftover from a
line of activity that developed earlier this afternoon along a
cold front which had outrun the boundary. The weak cold front
has now just about stalled over northwest Illinois and just
grazes our northwestern CWA. This front looks to basically
dissolve over the next several hours and shouldn`t play much of
a role in our weather from here. Latest RAP data indicates some
MLCAPE still resides over the CWA ahead of this front and a few
pieces of guidance suggest a couple of additional showers may
still try to develop late this evening. However, this will be
difficult to achieve with the cap reinforcing for the evening
in addition to a big lack of forcing and low-mid level dry
advection. That being said, it looks like the remainder of the
night should be primarily dry.
In other news, nearly calm winds and clearing skies should
promote fog development tonight, some of which could be dense.
Dewpoint temperatures this evening sit in the upper 50s to
lower 60s where temperatures are forecast to fall into the
middle 50s to near 60 degrees overnight. This looks like a
favorable setup for widespread fog development including
possible areas of dense fog, especially over parts of the CWA
that saw rain today. Any fog that develops late tonight should
stick around past daybreak possibly impacting portions of the
Friday morning commute.
Doom
&&
.DISCUSSION...
Issued at 256 PM CDT Thu May 16 2024
Through Friday night:
Scattered showers and thunderstorms will continue this afternoon,
though the coverage is expected to wane with sunset early this
evening. While occasional cloud-to-ground lightning and brief
heavy downpours can be expected with these storms, modest mid-
level lapse rates and deep layer shear are expected curtail the
severe weather threat. However, some instances of gusty winds (up
to 45 mph) and small hail will continue to be possible with the
strongest pulse-type storms. While the coverage of storms will
drop significantly with sunset, a low chance (20-30%) for a few
showers and storms will linger this evening. This is mainly the
case across parts of northern/northwestern IL in close proximity
to a weakening surface frontal boundary, and in advance of
another approaching mid-level impulse from western IA. For this
reason, I have held on to some low end POPs this evening, before
drying things out overnight.
During the overnight hours, low-level moisture is expected to
remain in place amidst decreasing cloud cover and light surface
winds (under 5 mph). This setup looks favorable for
overnight/early morning fog development. Conceptually, it`s easy
to envision pockets of dense fog (with visibility less than one
quarter of a mile) developing by daybreak, particularly in
areas where wet vegetation remains.
Any early Friday morning fog will then quickly erode during the
mid-morning hours, giving way to partly cloudy afternoon skies.
High temperatures near 80 will make for a spectacular and warm
May day. The exception will be along the Lake Michigan shoreline
as a lake breeze surges inland and results in cooler weather
during the afternoon hours. The day is largely looking to be
precipitation free for a majority of the area, especially for
areas along and north of I-80. However, farther south, another
weak disturbance and surface boundary could again foster a few
isolated to widely scattered afternoon showers and storms. There
is a 20-30% chance for some of these across areas well south of
I-80 Friday afternoon into the early evening. Dry and quiet
weather is then anticipated for Friday night.
KJB
Saturday through Thursday:
Unseasonably warm conditions are in store inland of Lake Michigan
through the weekend. Progged 925 mb temps support highs in the
lower to mid 80s both Saturday and Sunday, albeit with dew points
only in the mid 50s to around 60F keeping humidity levels and heat
indices in check. Onshore flow through the day on Saturday will
keep locations near Lake Michigan in the upper 60s to lower 70s.
Then on Sunday, a backdoor cold front slipping south and lake
breeze enhancement point toward similar high temps near the
lake.
Weak flow aloft and neutral to rising heights fitting a summer-
like pattern will combine with very dry mid-level air
(substantial dry air entrainment into incipient updrafts) to
greatly limit the threat for any showers and thunderstorms. Only
counter to the negating factors above will be the likelihood of
little to no capping. Thus, can`t rule out a widely isolated
afternoon shower or thunderstorm. On Saturday, a convergence zone
near and south of a Pontiac to Valparaiso line may provide just
enough low level lift for kick off sparse convection where 15-20%
PoPs are indicated. Turning to Sunday, the backdoor front and
inland lake-enhanced push of the front may trigger a field of
robust Cumulus. More prohibitively dry air aloft could preclude
any actual convection, thus for now only have silent PoPs around
10%. That said, a few models are showing splats of QPF, so we
may need to entertain some slight chance (~20%) PoPs in later
updates.
A warm front will surge north of the area on Monday, putting us in
the more humid warm sector amidst highs potentially well into the
80s. The magnitude of large scale forcing is somewhat
questionable, though there`s enough of a signal across the
guidance for chance (30-50%) PoPs across northern Illinois Monday
afternoon, increasing to 40-60% Monday evening and overnight.
Marginal deep layer shear looks to be a limiting factor for a more
appreciable severe threat, though wouldn`t be surprised at a
level 1 of 5 (marginal risk) threat for parts of the area. In
addition, PWATs up near or upwards of 1.5" (150-200%) could
support localized ponding/flooding.
The most "interesting" day next week convectively speaking
continues to be Tuesday. Another more substantial short-wave
trough and associated cyclogenesis over the Plains (tracking
northeastward) introduce the prospect for a more synoptically
classic set-up for thunderstorms, severe weather, and flooding
over the region. As is typical at this range of the forecast,
there`s plenty of uncertainty in the evolution of key features
and mesoscale influences of multiple potential waves of
convection. At this juncture, felt comfortable indicating
"showers and thunderstorms likely" in the official forecast and
recommend keeping an eye on this period as it draws closer. The
systems cold front will likely sweep across the area sometime
Tuesday night or early Wednesday and result in a quieter and
more seasonable period through Thursday (current day 7).
Castro
&&
.AVIATION /00Z TAFS THROUGH 06Z FRIDAY/...
Issued at 619 PM CDT Thu May 16 2024
Key Aviation Messages:
- Isolated to widely scattered TSRA this evening, primarily for
the Chicago metro TAFs.
- Light/variable winds overnight into Friday morning, with
potential for fog/low stratus development especially west of
Chicago.
- Winds remain light/variable Friday, though a lake breeze
should bring east-northeast winds to KORD/KMDW/KGYY by
afternoon.
Weak surface low pressure was over the upper Peninsula early
this evening, with a weak cold front pushing slowly east across
the Mississippi River into western IL. Ahead of the front,
isolated to widely-scattered showers and thunderstorms were
occurring from near KMKE to southwest of KDKB and just west of
KMQB. These showers/storms were moving to the east at around 15
mph, and will continue to push east into northeast IL this
evening. Current radar trends suggest activity southwest of KDKB
will pass south of KORD/KMDW through 02-03Z, with an eventual
weakening/dissipating trend with sunset and the loss of diurnal
instability. Have maintained a VCTS mention for the Chicago
terminals, except for KGYY where storms may dissipate before
approaching the field.
The cold front is forecast to wash out across the area tonight,
with light/variable winds and little scouring of low-level
moisture. This will likely set the stage for some patchy
fog/stratus development after midnight, with IFR/LIFR conditions
possible. Some guidance hits this pretty hard, though confidence
is low enough to limit IFR mention to KDPA/KRFD for now, where
there is a bit better model agreement with the foot print. Will
continue to monitor for development into tonight for possible
lower conditions needed at the major Chicago terminals.
Any fog/stratus should burn off by mid-morning Friday, with VFR
conditions then expected. Winds will remain somewhat light and
variable within a weak pressure gradient, which should support
an east-northeast lake breeze to develop for KORD/KMDW/KGYY by
early afternoon. Can`t rule out some lingering stratus/fog over
the lake which could attempt to push inland, but would think it
would be limited to areas closer to the shore with inland
locations remaining VFR.
Ratzer
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
Visit us at weather.gov/chicago
Area Forecast Discussion
National Weather Service Memphis TN
900 PM CDT Thu May 16 2024
...New UPDATE...
.UPDATE...
Issued at 845 PM CDT Thu May 16 2024
Evening update consisted mostly of adjusting PoPs to reflect the
ongoing and near-term convection trends. 00Z CAMs have backed off
significantly on the supportive severe weather potential
overnight; the Marginal Risk (level 1 out of 5) has been trimmed
out of the area. We will still likely see a wave of scattered
showers and thunderstorms surging up from the Mississippi Delta
overnight, but the potential strength of these storms is now
looking less impactful. That`s not to say that a few rogue storms
couldn`t produce gusty winds or hail, but these would likely be
few and far between. Expect heavy cloud cover and southeasterly
winds to keep temperatures on the balmy side in the upper 60s.
CAD
&&
.SYNOPSIS...
Issued at 239 PM CDT Thu May 16 2024
Pleasant and dry conditions will come to an end tonight as a few
systems cross the region. Showers and thunderstorms, some may be
strong to severe, are possible tonight and tomorrow. Tonight`s
potential for severe weather looks to be north of Interstate 40 and
tomorrow may be more widespread. There is low confidence in severe
weather chances tonight and tomorrow. A Flood Watch goes into effect
tonight at 7 PM for areas along the TN/KY and AR/MO borders. High
pressure settles in on Sunday and temperatures will be on the rise
and our first 90 degree day will arrive early next week. Rain
chances return early next week.
&&
.DISCUSSION...
(This evening through next Wednesday)
Issued at 239 PM CDT Thu May 16 2024
An MCV on track across Arkansas into Missouri may bring a few
strong, possibly severe storms to the Mid-South late tonight. Any
development will most likely be confined to north of the I-40
corridor. This MCV is approaching the region, but it is struggling
to push a shortwave ridge out of the way and saturate the column.
The 12z sounding from LZK showed a very dry air column with a stable
near surface environment. By the time the MCV reaches the area, it
will be running out of daytime heating and diurnal stability trends.
There may be just enough CAPE and shear (~600 J/kg and ~25 kts of 0-
6km shear) for a strong storm or two, but a severe weather window is
very narrow if at all.
A deep trough under southerly flow aloft will push across the
southeast from the southern plains. The strength of this trough will
be highly dependent on how long the decaying MCV takes to push out
of the Mid-South and if the atmosphere has enough time to recover.
Models have come to a bit better agreement than this time yesterday
to keep showers and a few thunderstorms around until late Saturday
night. Current CAMs do not indicate any redevelopment and have the
MCV to cross tonight to squash any new convection from firing
tomorrow. Deterministic soundings are not impressive for tomorrow and
cloud cover and any lingering showers should help keep the
environment behaved tomorrow.
PWs are at or above the 90th percentile for Friday morning through
the afternoon. A Flood Watch will go into effect tonight at 7 PM for
areas along the TN/KY and AR/MO borders until 7 PM Saturday. The
aforementioned areas could see up to 2 inches from tonight through
Saturday with already saturated soils. The 75th percentiles for rain
for this area exceeds 3 inches or higher. High pressure begins to
settle in Sunday, and we could see our first 90 degree days of the
season on Monday. Rain chances increase again Tuesday through the
middle of the week.
DNM
&&
.AVIATION...
(00Z TAFS)
Issued at 703 PM CDT Thu May 16 2024
Confidence in TSRA at MEM is marginal during the overnight hours.
A low level jet with southerly winds around 35KT will develop
around FL020, which should feed scattered to numerous SHRA. A 22Z
HRRR proximity sounding for 10Z at MEM depicts insufficient
instability for TSRA, despite the model depicting 50dBZ simulated
radar cores immediately west over eastern AR. Will reevaluate
overnight TS chances for 03Z MEM TAF amendment.
Cloud cover and early day rainfall should limit instability and
TSRA chances on Friday. IFR CIGs are likely, until a weak frontal
boundary returns north in the afternoon. LAMP and NBM appear to
hold on to IFR CIGs too long after this boundary returns north.
PWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Flood Watch through Friday evening for ARZ009-018.
MO...Flood Watch through Friday evening for MOZ113-115.
MS...None.
TN...Flood Watch through Friday evening for TNZ001>004-019>022.
&&
$$
PUBLIC FORECAST...DNM
AVIATION...PWB
Area Forecast Discussion
National Weather Service Marquette MI
658 PM EDT Thu May 16 2024
.KEY MESSAGES...
- Showers into the evening hours. A few rumbles of thunder possible.
- A slight ~30% chance for thunderstorms exists across the
western UP Friday afternoon and evening then over the
Keweenaw Friday night.
- A southerly breeze and very warm temps in the 70s and 80s
Saturday ahead of a cold front that brings a higher ~50%
chance for afternoon thunderstorms. The strongest storms may
contain small hail.
- Elevated fire weather possible on Saturday then very dry with
light winds on Sunday.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 340 PM EDT Thu May 16 2024
Water vapor imagery and RAP analysis show a well-defined shortwave
trof extending from southern Manitoba to the western Great Lakes. A
vort max is clearly evident over n central WI. After a bit of a
diminishing trend late morning, shra are expanding this aftn ahead
of this feature. There has been some thunder to the s of Upper MI
from the Green Bay area to portions of the Door Peninsula. Current
temps range from the Upper 60s in eastern Upper MI where there has
been some filtered sunshine thru high clouds to the upper 40s/lwr
50s F w where clouds and sct shra have kept temps down.
Vort max will swing ne across Upper MI during the late aftn and
evening, supporting shra in its vcnty and ahead of it. There is up
to 200-300j/kg of CAPE avbl for parcels lifted from above sfc based
stable layer. So, can`t rule out a few rumbles of thunder. The shra
will be more nmrs across the e half of Upper MI where low-level jet,
850mb theta-e advection and weak isentropic ascent will be focused.
Shra will end most areas by midnight. With light winds overnight and
low-level moisture from rainfall, some fog may develop. Expect lows
tonight to range thru the 40s F.
&&
.LONG TERM /FRIDAY THROUGH THURSDAY/...
Issued at 524 PM EDT Thu May 16 2024
Several low to medium-impact forecast challenges persist with the
current forecast package 1) Friday/Saturday afternoon thunderstorm
chances, 2) fire wx concerns interspersed between brief rain
chances, and 3) widespread rain potential next week. Both chances
for thunderstorms include low probabilities for strong storms
capable of gusty winds and small hail, but instability seems
insufficient for severe hazards. Borderline fire wx concerns return
Friday afternoon with elevated conditions possible this weekend,
especially on Saturday when gusty south winds may accompany hot
temperatures >80F. Details of the early next week pattern remain
murky, but potential for frequent rain chances if not widespread
soaking rain seems to be increasing.
Beginning with Friday, the UP will be positioned between systems,
but a weak and low-amplitude shortwave ripples along the northern
periphery of 500 mb ridging during the afternoon hours. This impulse
may be associated with a warm front lifting northeast across the
region. As a result, warm air advection and veering wind profiles
are apparent and would be favorable for thunderstorms -perhaps even
strong storms- if sufficient moisture/instability materializes. HREF
means advertise around 500 J/kg which is insufficient for strong
storms. However, individual CAMs advertise localized pockets of 1000-
1500 J/kg across the interior west, which is sufficient for small
hail and gusty winds. Regardless, the spatial and temporal extents
of this threat appear small and it`s more likely that thunder
doesn`t occur. As the warm front lifts north across the area a
nocturnal thunderstorm threat may emerge on the nose of a ~40 kt
LLJ. Most guidance keeps this activity over the lake, but it could
scrape the Keweenaw so I left schc PoPs. Also with WAA spreading
across the area and EFI guidance highlighting unseasonably warm lows
across the west, decided to nudge the forecast upwards so that
western downslope locations only cool into the upper 50s Friday
night with mid 40s to around 50 elsewhere.
By Saturday morning, the UP will be squarely in the warm sector of a
surface low near Lake Winnipeg with 850 mb temps of 14-16C spreading
across the UP. This unseasonably warm air mass supports high temps
surging into the 80s and a stout south breeze should prevent a lake
breeze off Superior, in fact a few downslope locations (e.g. Big
Bay, L`Anse, Ontonagon) may reach the mid-80s. However, south flow
off Lake MI keeps the eastern UP mainly in the 70s to perhaps even
60s along the shorelines. EFI highlights the unseasonably warm temps
well and also hints at the possibility of unseasonably strong wind
gusts across the far west where model soundings indicate potential
for gusts into the 30-35 mph range. The combination of hot temps and
gusty winds suggests potential for elevated fire wx conditions, but
the main limiting factor is RH values as dew points surge to around
50F. Elevated dew points also result in afternoon/evening thunder
chances as the systems cold front presses across the area as CAPE
values increase to around 750-1250 J/kg. Bulk shear values are in
the 25-35kt range on most guidance indicating a convective
environment that is barely favorable for marginally severe hail or
winds, but the SPC decided not to outlook our area. Ultimately,
timing of the frontal boundary will be critical for thunderstorm
potential in our area.
A much drier air mass and associated surface ridging follows the
frontal passage for Saturday night into Sunday. Abundant sunshine
and light winds results in deep mixing into an extremely dry mid-
level layer on Sunday. For example, the 12z NAM advertised a -48C
dew point at 734 mb at 1 PM Sunday. Fortunately surface dew points
won`t mix that low, but I still made substantial cuts to Td values
resulting in minRHs around 20% across the interior west. Light winds
less than 10 mph are the silver lining for fire wx concerns, because
critically low RHs appear nearly certain across interior portions of
the UP. Lake breeze activity should limit fire wx concerns along the
shorelines.
Quickly glancing at the long-term period, model support appears to
be increasing for a wet stretch of weather including widespread
soaking rainfall early next week. The latest EPS surface low tracks
develop a low near Rapid City, SD that lifts northeast across MN
into far northwestern Ontario Sunday night into Monday. Warm/moist
air advection ahead of this system brings rain chances back into the
area. As the Ontario low departs on Monday it appears to leave a
trailing frontal boundary across the Upper Great Lakes as a sub-1000
mb surface low develops over the south-central Plains. This
deepening low pressure tracks along the frontal boundary into the
Great Lakes region on Tuesday/Wednesday bringing the potential for
heavy precipitation.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 658 PM EDT Thu May 16 2024
Showers will move continue to move out. As low-level moisture
increases, cigs will stay low. MVFR conditions at IWD will become
VFR overnight and stay that way through Friday. VLIFR conditions at
CMX will continue until later tonight when MVFR moves in and then
VFR by Fri morning. SAW will have LIFR conditions this evening and
then VFR conditions later on tonight.
&&
.MARINE...
Issued at 524 PM EDT Thu May 16 2024
Light winds of generally 20 knots or less continue today into early
next week, except for Saturday afternoon and evening when southerly
gusts of 20-25 kts are forecast ahead of a cold front. Patchy dense
fog is possible in areas of rainfall this evening through tonight. A
few rumbles of thunder are possible this evening across the eastern
lake. Additional thunderstorm chances occur as a warm front lifts
across the lake Friday evening followed by a cold front Saturday
evening. The strongest storms along Saturday`s cold front may
contain small hail, gusty and erratic winds, and frequent lightning.
Thunder chances return Monday as a series of disturbances track
northeast across the Upper Great Lakes region.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...EK
AVIATION...07
MARINE...EK
Area Forecast Discussion
National Weather Service Blacksburg VA
851 PM EDT Thu May 16 2024
.SYNOPSIS...
Another storm system will cross the area Friday through late
Sunday. This system will bring widespread rain to the area.
Monday and Tuesday look drier. High temperatures generally look
to be in the 60s and 70s through the weekend, with a slight
warming trend into next week.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 845 PM EDT Thursday...
Key Messages:
1) Isolated showers will dissipate by midnight
2) Rain returns Friday
HRRR and other Hi-Res guidance have the remaining showers over
the region dissipating by midnight. Bufkit forecast soundings
show fog developing in the typical river valley late this
evening.
Mid and high clouds spread into the area from the southwest
overnight. No changes made to forecast minimum temperatures.
Previous discussion:
As of 135 PM EDT...
Upper low is currently spinning just off the New Jersey coast
this afternoon. Flow is generally from the northwest with a weak
stalled boundary across West Virginia. Widespread cumulus clouds
continue, but have had enough breaks in the cloud cover to warm
up nicely already. As we continue to heat, may have a few
isolated showers or a thunderstorm or two develop across the
area this afternoon. Any rain or thunderstorm activity wanes by
sunset with the loss of daytime heating.
Clearing skies tonight will calm winds and residual low level
moisture will likely lead to areas of dense fog throughout the
area.
An open wave over the Plains today will move east, situated over
the Tennessee Valley by Friday morning. Flow will return to
southwest and a weak boundary draped across the region will be
the focus for a renewed chance of rain and thunderstorm activity
by Friday afternoon. Localized heavier downpours could lead to
some minor flooding issues.
With breaks in the clouds today, this will be the warmest day
with afternoon highs topping out in the mid 70s to low 80s.
Tomorrow, clouds and rain will hamper daytime heating a bit so
highs tomorrow mostly in the 70s. Overnight lows remain mild in
the 50s to low 60s.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 110 PM EDT Thursday...
Key Messages:
1) Confidence is high for more unsettled weather with chances of
showers and thunderstorms throughout this weekend.
2) There is a marginal risk of flooding due to the potential for
repeated rounds of rainfall.
A cold front will enter the Mid Atlantic on Friday night to bring
high chances of showers and thunderstorms. The storms should weaken
by early Saturday morning as the atmosphere becomes more stable.
Ample moisture should be available due to a southeast flow advecting
air from the Atlantic Ocean. Some thunderstorms may develop again by
Saturday afternoon due to increasing instability aloft as an upper
level low approaches. This upper level low should pass overhead by
Saturday night into Sunday to continue the unsettled weather, but
the thunder threat will dip lower as the flow turns to the northeast
and advect cooler air towards the Appalachian Mountains.
With this prolonged period of wet conditions from repeated rounds of
rainfall, there is a marginal risk of flooding for poor drainage or
low-lying areas. Some locations could see one to two inches with
locally higher amounts over the weekend, but it will be the heavier
rainfall rates from storms that pose the main concern for any
hydrological issues. The risk of severe weather also appears to be
low, but there may be some stronger storms possible if enough
instability is available. Temperatures were kept to the cooler side
of model guidance due to the abundant cloud cover and ongoing
chances of showers and thunderstorms.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 110 PM EDT Thursday...
Key Messages:
1) Confidence is moderate for drier conditions to return during
Monday and Tuesday.
2) The next chance of showers and thunderstorms may arrive
by Wednesday from a cold front.
The upper level low should slowly drift off the North Carolina coast
by Monday, and the models are starting to indicate better agreement
for drier weather. Meanwhile, ridging will take place across the
Appalachian Mountains. With high pressure taking firmer control by
Tuesday to provide more sunshine, a warming trend should ensue. Even
warmer air will arrive by Wednesday from southwest flow ahead of the
next cold front. However, most of the dynamical energy with this
front should pass well to the north in Canada, so just a chance of
showers and thunderstorms are expected for Wednesday afternoon into
Wednesday night. Weak high pressure could follow by Thursday to
offer lower chances of rain.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
As of 745 PM EDT Thursday...
Starting the forecast period with scattered VFR clouds and
isolated showers. The showers may have brief periods of MVFr
visibility due to heavy rain but the coverage is limited and the
probability of impacting any of the local airports is low. These
showers will dissipate by 03Z/1PM.
Bufkit forecast soundings and models have a layer of IFR to LIFR
low clouds spreading east from the coast and reaching central
Virginia late tonight. Bring these low clouds into KLYH after
06Z/2AM.
Wind speeds will diminish this evening and with a mostly clear
sky IFR/LIFR fog will develop in river valleys. Bufkit suggested
the fog will form at KLWB/KBCB and KBLF as early as 05Z/1AM. Will
see improvements by 12z-13z/8-9AM with the visibility returning
to VFR.
Mid and high clouds will fill in from the southwest throughout
the day. Models and Bufkit showed enough heating by 22Z/6PM in
far southwest Virginia and northwest North Carolina to overcome
a mid level cap. Have added -ra to the end of KBLF and KBCB
TAFs.
Average confidence for formation of fog and the associated
visibilities tonight.
Average confidence for timing of precipitation on Friday.
EXTENDED AVIATION OUTLOOK...
Sub VFR likely with rain and low clouds on Friday night.
Precipitation will continue through the weekend with numerous
showers and thunderstorms on Saturday and Saturday night.
MVFR/IFR clouds and showers remain in the area for Sunday and
Sunday night.
Some improvements by Monday as the slow moving storm system
begins to depart east. Tuesday is the most likely day to be VFR.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...BMG
NEAR TERM...AMS/BMG
SHORT TERM...PW
LONG TERM...PW
AVIATION...AMS/BMG
Area Forecast Discussion
National Weather Service Tallahassee FL
946 PM EDT Thu May 16 2024
...New UPDATE, MARINE...
.UPDATE...
Issued at 931 PM EDT Thu May 16 2024
This evening update features a significant uptick in rain chances
per radar trends and CAM guidance. An ongoing MCS over
southwestern Louisiana is poised to continue moving eastward along
the northern Gulf Coast through the overnight hours. Ahead of this
complex of storms, isolated showers and a rumble of thunder are
possible, mostly near and offshore of the Emerald Coast through
about 3 AM CT. Afterward, we`ll be watching the MCS approach our
forecast area. The storms will likely be elevated given that we`ll
likely still be north of the warm front. Thus, severe storms are
currently not anticipated, but wouldn`t be surprised if storms
contain frequent lightning and some small hail. The strongest
storms look to be near and offshore of the Emerald Coast, but
we`ll continue to monitor through the night.
The MCS will likely make it into our Panhandle counties close to
sunrise Friday morning, then traverse across the rest of the area
Friday morning. While not explicitly forecast, the last several
runs of the HRRR have indicated wake low development on the
backside of this complex. If this were to materialize, then gusty
winds will be possible Friday morning, especially near the coast.
However, confidence in convective evolution is too low for
inclusion in this forecast update. Will let the next shift
evaluate trends.
&&
.NEAR TERM...
(Through Friday)
Issued at 347 PM EDT Thu May 16 2024
Surface high pressure is centered over the northeast Gulf this
afternoon. High pressure will move east across the Florida Peninsula
tonight, then continue on to northeast of the Bahamas on Friday.
In response, low-level southerly flow will get underway and
gradually increase, bringing a return of deeper and richer surface-
based moisture by Friday morning. A warm front will then continue
northward on Friday afternoon through our Alabama and Georgia
counties, bringing a warmer and moister air mass northward.
Meanwhile, 700-500 mb flow will back around south of due west and
increase in strength, in response to an eastward-propagating and
positively tilted upper trough traversing the Southern Plains. The
first of multiple shortwaves will eject through the strengthening
mid-level flow, zipping across our region early Friday morning. This
will drive the cluster of storms currently over eastern Texas
eastward overnight. By the time they get this far east, the storms
will have weakened some and could very well be elevated on the cool
side of the northward-advancing warm front. Later on Friday, there
could be a temporary lull over our Florida counties, but convection
could continue to occasionally fire off over our Alabama and Georgia
counties thanks to lift provided by the northward-advancing warm
front.
&&
.SHORT TERM...
(Friday night through Saturday night)
Issued at 347 PM EDT Thu May 16 2024
The potential for severe weather is increasing and SPC has
upgraded western portions of the area from a Marginal to Slight
Risk on the latest Day 2, valid Friday night into Saturday
morning. Meanwhile, the remainder of the region is now in an
SPC Marginal Risk. One or more rounds of thunderstorms is
expected. The first round could occur or be ongoing as early as
Friday night, although the more significant round is expected
on Saturday into Saturday night. The high shear values are
more reminiscent of the cool season while decent instability
is expected. Damaging winds and possibly a tornado appear to be
the main threats. Those with outdoor/travel plans should
remain weather aware and adjust plans in advance accordingly.
&&
.LONG TERM...
(Sunday through Wednesday)
Issued at 347 PM EDT Thu May 16 2024
Depending on the timing, a chance of showers and thunderstorms could
linger across the eastern half of the area for Sunday. Cannot rule
out a slight chance of showers across far eastern areas on Monday
as another shortwave swings through. Otherwise, dry conditions
look to dominate heading into the middle of next week with
temperatures slightly above average.
&&
.AVIATION...
(00Z TAFS)
Issued at 732 PM EDT Thu May 16 2024
A return of low-level southerly flow will get underway over the next
24 hours, as surface high pressure exits off to the east.
FEW-SCT coverage of fair weather cumulus is expected until sunset,
when thermal lift will end. Then late tonight, the southerly flow
will spread mainly MVFR cigs northward into across the FL terminals
(ECP and TLH). Around or after sunrise, the elevated and weakening
remnants of thunderstorms currently over eastern Texas will make
their way in from the west.
Have included VCTS at ECP only. Have only included showers at the
other terminals through 18z Friday, but will need to watch for
eventual inclusion of thunder.
&&
.MARINE...
Issued at 931 PM EDT Thu May 16 2024
Main changes to tonight`s forecast is to increase the rain
chances, especially over the western waters. A complex of storms
will move over the northern Gulf waters late tonight into Friday
morning, perhaps remaining strong. Additionally, several runs of
CAM guidance indicates a wake low could develop on the backside of
these storms. If this materializes, then gale force gusts could be
possible as storms depart. Confidence in this scenario is too low
for explicit inclusion at this time.
From CWF Synopsis...Southerly breezes will start to increase on
Friday as high pressure moves east of the waters. A cluster of
strong thunderstorms is possible late tonight into Friday morning,
possibly containing strong winds, frequent lightning, and small
hail. A cluster of strong to severe storms is possible on Saturday
ahead of a cold frontal passage. Showers and storms could linger
into Sunday with the front nearby. High pressure and light winds
are expected to return for early next week.
&&
.FIRE WEATHER...
Issued at 347 PM EDT Thu May 16 2024
A weak front will approach the area on Friday and Saturday, passing
the districts on Sunday. In advance of the front on Friday and
Saturday, multiple clusters of thunderstorms are likely to cross the
area, with the heaviest rain and greatest potential for severe
storms coming on Saturday. Behind the front on Sunday afternoon, the
air mass will start to dry out. High afternoon dispersion is
forecast over inland districts on Sunday afternoon due to a deep
mixed layer and moderate westerly transport winds.
&&
.HYDROLOGY...
Issued at 347 PM EDT Thu May 16 2024
Both the Withlacoochee River at Valdosta and Ochlockonee River at
Concord continue in minor flood stage. More rain is headed into the
area for the end of this week into the weekend. The current expected
rainfall amounts are in the 1-3 inch range over most of the area,
but locally heavier amounts cannot be ruled out, particularly if
thunderstorms moved repeatedly over the same areas. Thus, there is a
marginal to slight risk of excessive rainfall across the area from
the WPC excessive rainfall outlook, mainly on Saturday.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 69 88 73 84 / 30 50 20 80
Panama City 71 85 72 82 / 60 50 30 80
Dothan 69 86 71 81 / 50 70 40 90
Albany 68 86 72 83 / 20 70 40 90
Valdosta 68 89 73 87 / 10 30 20 80
Cross City 66 89 73 87 / 10 30 10 70
Apalachicola 73 83 74 81 / 40 40 20 70
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through late Sunday night for FLZ108-112-
114-115.
GA...None.
AL...None.
GM...None.
&&
$$
UPDATE...Young
NEAR TERM...Haner
SHORT TERM...LF
LONG TERM....LF
AVIATION...Scholl
MARINE...LF/Young
FIRE WEATHER...Haner
HYDROLOGY...DVD