Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/30/18
Area Forecast Discussion
National Weather Service Binghamton NY
947 PM EDT Tue May 29 2018
.SYNOPSIS...
High pressure will build into the region through Wednesday,
bringing warm temperatures and mainly dry weather. Patchy valley
fog may form early Wednesday morning in favored locations.
Showers begin to overspread the area by Wednesday night. Later
this week, tropical moisture will move northward into the
region, resulting in unsettled weather with showers and
thunderstorm chances.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
930 PM Update...Isolated showers with a few cloud flashes of
lightning developed earlier this evening over the southern
Catskills and Poconos regions. This activity has dissipated,
leaving behind scattered mid-level cumulus clouds. The last few
runs of the HRRR showed a renewal of shower and even
thunderstorm activity over NE PA...but at this time, feel this
is overdone. With the loss of daytime heating the latest SPC
mesoanalysis shows ample CIN in place here now. Could however
see an additional stray shower or two in NE PA through midnight.
Removed any mention of thunder from the grids this evening. Dry
and mostly clear elsewhere overnight. Could see some patchy
valley fog develop over the southern tier of NY and northern
tier of PA toward morning...either way this will burn off by
mid-morning. Also watching for a lower stratus cloud deck to
form in the developing easterly maritime flow over the Poconos
late tonight and into the day Wednesday...these clouds could at
times overspread the Wyoming Valley region as well. Added in
some patchy drizzle late tonight and Wednesday AM over the
higher Poconos of Lackawanna, Luzerne, Wayne and Pike counties.
Otherwise, Wednesday afternoon will see clouds gradually
increasing from southwest to northeast across the area, with a
slight chance of showers southwest of a Hornell--Towanda--
Scranton line. It should remain dry across Central NY and very
warm across the Finger Lakes and Lake Plain as southeast
downsloping winds increase (10-20 mph). Highs Wednesday will
range from the mid-70s over the Poconos/Catskills to 85-90 in
the valleys of Central NY.
&&
.SHORT TERM /WEDNESDAY NIGHT/...
350 AM Update...
Showers will multiply during the short term period as axis of
abundant moisture overtakes the region. However, a relatively
cool and cloudy southeast low level flow will limit the amount
of instability which should hold back rain amounts from becoming
excessive, even on a localized level.
Upper level ridge will shunt east Wednesday night, opening up our
region to southwesterly flow aloft that will have a moisture
tap all the way from the Gulf of Mexico. Precipitable water
values will get well over 1.5 inches, to between 2 and 3
standard deviations above normal for the end of May. However, a
decent pressure gradient will exist between high pressure
centered just offshore of New England, and low pressure in the
Upper Midwest. Low level southeasterly winds will keep a
relatively cooler more stable feed of air going over the region,
which along with overcast sky will very much limit the amount
of instability during the short term period. Downsloping flow
into the northern Finger Lakes to Syracuse areas may allow
temperatures to get near 80 degrees Thursday, and perhaps a
modest amount of instability, but only upper 60s-mid 70s will be
found elsewhere. Though warm cloud depth will be fairly thick,
steering winds while not strong will be good enough - 15 to 25
knots - to move along individual showers which along with
inhibited convection will keep rain amounts from becoming too
heavy. Thunder chances, though limited, will be higher well
west of I-81. To the east the stable layer will be quite thick.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
225 PM Update...
In the big picture, there will be a trough over the northeast
US. It will be unsettled with showers and thunderstorms through
the weekend. Models differ on timing of drier weather moving in
next week.
Thursday, warm humid air will move in from the west setting off
showers and some thunderstorms. There will be a warm front
between this airmass and cooler and drier air with high pressure
moving off the New England coast. This moisture will be
tropical well ahead of an upper level trough. Remnants of
Alberto will move north the next 2 days and get captured by the
trough in the Midwest and Ohio Valley. PWATs approach 2 inches
which is near climatological max for the end of May. Winds are
light and forcing is weak. Heavy rain is likely but where and
for how long is very uncertain at this time.
The upper level trough and a surface cold front move slowly east
to cross our region from northwest to southeast Friday afternoon
and Friday night. This could be when some flash flooding could
be possible especially if heavy rain falls Thursday and Thursday
night. These showers and thunderstorms could linger across PA
Saturday. At upper levels low pressure will be over the mid
Atlantic pumping moist cool air into our region.
Sunday could be more showers for PA and maybe NY as another
upper level trough moves in and joins the stagnant low pressure
on the East Coast. Monday this exits leaving a mainly dry day.
Tuesday models show another cold front dropping southeast
through the region. This could be dry with the showers this
weekend lingering longer.
Temperatures will start out a good 10 degrees above normal
Thursday to Friday with highs in the 70s to low 80s. Near normal
Saturday on with more clouds. Lows in the 50s and highs around
70.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions will persist through the period at KSYR, KRME,
KITH and KBGM with just some sct to bkn mid and high level
clouds around on Wednesday. Occasional MVFR CIGS are possible
at KAVP Wednesday morning as a low marine stratus cloud deck
attempts to move in from the east off the Pocono plateau.
Restrictions (possibly IFR/LIFR for a time) are also expected at
KELM in fog early Wednesday morning. The fog should quickly
lift and disperse after 30/13-14z...with conditions returning to
VFR at KELM for the rest of the day.
Winds will become light and variable overnight, less than 10
kts. Winds shift out of the east-southeast on Wednesday,
gradually increasing to between 8-15 kts...with a few higher
gusts possible, especially at KITH, KELM and KBGM.
Outlook...
Wednesday night through Sunday...Scattered showers and
thunderstorms may cause periodic restrictions.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...RRM/MJM
NEAR TERM...MJM
SHORT TERM...MDP
LONG TERM...TAC
AVIATION...MJM
Area Forecast Discussion
National Weather Service Boston/Norton MA
949 PM EDT Tue May 29 2018
.SYNOPSIS...
Mainly dry weather with warm afternoons are anticipated away from
the coast through Thursday. A complex weather system, including the
remnants of Alberto, will slowly push into the region Thursday night
and likely lingering into the upcoming weekend. This will bring
showers and scattered thunderstorms. Some storms could bring
locally heavy rainfall. Cooler but dry conditions will move into
the region on Sunday.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
950 pm update...
***Dense Fog Advisory South Coast/Cape And Islands***
The main issue overnight will be the potential for dense fog
near the south coast, Cape and Islands. Very light south wind
ahead of a backdoor cold front with dewpoints near 60 will
result in ideal conditions for this risk. Fog is always a
challenge to forecast, but given support from the NARRE and HRRR
felt it was worth the Dense Fog Advisory near the south coast.
Further north, larger temperature/dewpoint spreads and earlier
arrival of the cold front will probably limit extent/duration of
any fog.
Low temperatures by daybreak will range from the 50s to the
lower 60s.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Wednesday...
Any morning low clouds/fog and patchy drizzle will burn off or lift
into a scattered deck of strato-cu clouds. Much cooler than today
given 1022 mb high over the Gulf of Maine. However still a very
pleasant day with partly to mostly sunny conditions and temps
warming to near seasonal levels with highs in the 70s to near 80
from Hartford to Springfield. Cooler along the eastern MA coast with
highs only in the 60s due to easterly onshore winds.
Wednesday night...
1020 mb high pres over the area providing dry and seasonably cool
conditions with lows mainly in the upper 40s to lower 50s, mid 50s
for the urban areas. Given the light winds, mostly clear skies
leaned toward the cooler MOS temps.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Highlights...
* Warm and humid Thursday into Saturday
* On and off showers late Thursday into early Saturday
* Potential backdoor/cold front late Saturday/Sunday
Details...
Complex weather scenario setting up for the region beginning on
Thursday lasting into next week. Difficult to narrow down the timing
as model spread is still quite large, as well as hi-res
guidance would provided better detail. However, will focus on
the trends for the end of the week into the weekend.
Thursday into Saturday...
Remnants of Alberto will move northward and interact with
approaching shortwave trough from the Great Lakes by Thursday. Most
of the region will stay dry as upper level ridge and surface high
pressure will be over the region, but they will begin to move
offshore during the day. This will allow left over moisture from
Alberto to move into the area, increasing humidity and shower
chances for the area. Depending on when the atmosphere will moisten
up, feel that most of the day on Thursday will remain dry until the
afternoon as high theta-e values move from west to east into
SNE. This tropical airmass will remain in the area through Thursday
night into Saturday as the pattern because somewhat blocked from
stalled off cut-off low east of the Maritimes.
PWAT values with this tropical airmass will reach above 2 inches,
which is near 2-3 STD above normal. Dewpoints could reach above 65-
70F which could lead to SB Cape values above 1000 J/KG. This
instability combined with the moisture could lead to sct thunder.
Steering flow is not that great so shear is not all that impressive,
so main threat with any storm would be heavy rainfall leading to
localize flooding. Stay tune to this portion of the forecast as we
continue to fine tune it.
Sunday...
One change to the forecast is the potential for a dropping cold
front from the north/back door front moving into the region late
Saturday and into Sunday. Lots of dry air looks to move in behind
this front which could lead to a dry Sunday thanks to building high
over Maine. However, with the flow off the water, could see
temperatures into the low to upper 60s. Still some timing issues
with this system.
Early next week...
Cut-off low pressure system continues to linger south of the region.
This low will get caught up in the northern stream resulting in
another round of wet weather during the Monday/Tuesday time frame.
Depending on locations of fronts and surface lows, temperatures will
be improving from the 60s on Sunday into the mid 70s by Tuesday.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Wednesday Night/...
After 00z...
Forecast challenge becomes low clouds and fog offshore returning
as low level winds become southeast. Highest probability for
IFR/LIFR returning appears across the south coast and eventually
pushing into central MA. Low probability elsewhere. Otherwise
dry weather prevails.
Wednesday...
Low probability of lingering IFR/LIFR in low clouds/fog until
15z across CT possibly into RI and western-central MA. Then VFR
all areas by 16z.
Wednesday night...
VFR, dry weather and light winds.
KBOS Terminal...VFR and dry weather. Low clouds and fog
offshore should remain south and west of the terminal tonight
and Wed. Still cannot rule it out. Sea breeze weakens later
this evening, possibly becoming light northeast overnight.
KBDL Terminal...Low clouds and fog offshore may overspread the
area later tonight into Wed morning before clearing out by
midday Wednesday.
Wednesday Night: VFR and dry weather.
Outlook /Thursday through Sunday/...Moderate confidence.
Thursday: Mainly VFR, with local MVFR possible. Slight chance
SHRA.
Thursday Night: Mainly IFR, with local MVFR possible. Slight
chance SHRA, patchy BR.
Friday: Mainly VFR, with local IFR possible. Chance SHRA,
slight chance TSRA.
Friday Night: MVFR/IFR conditions possible. Chance SHRA, slight
chance TSRA, patchy BR.
Saturday: Mainly VFR, with areas MVFR possible. Chance SHRA,
slight chance TSRA.
Saturday Night through Sunday: VFR. Breezy. Chance SHRA.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Wednesday Night/...
Tonight...
1024 mb high over Quebec moves into Maine tonight with ENE winds
developing. Low clouds and fog south of Marthas Vineyard and
Nantucket late today may drift back into the RI waters late tonight
resulting in low vsby in patchy fog and drizzle. Elsewhere no vsby
issues.
Wednesday...
Patchy fog and drizzle over the RI waters during the morning burns
off giving way to good afternoon vsby. 1022 mb high settles over the
Gulf of Maine providing light and variable winds.
Wednesday night...
Tranquil boating weather as 1020 mb high builds over the region.
Thus dry weather and good vsby.
Outlook /Thursday through Sunday/...Moderate confidence.
Thursday: Winds less than 25 kt.
Thursday Night: Winds less than 25 kt. Slight chance of rain
showers, patchy fog. Visibility 1 to 3 nm.
Friday: Winds less than 25 kt. Slight chance of rain showers,
isolated thunderstorms.
Friday Night: Winds less than 25 kt. Chance of rain showers,
slight chance of thunderstorms, patchy fog. Visibility 1 to
3 nm.
Saturday: Winds less than 25 kt. Areas of seas approaching
5 ft. Slight chance of rain showers, isolated thunderstorms.
Saturday Night: Winds less than 25 kt. Seas up to 5 ft. Chance
of rain showers.
Sunday: Moderate risk for Small Craft Advisory winds with gusts
up to 25 kt. Areas of rough seas. Chance of rain showers.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...Dense Fog Advisory until 6 AM EDT Wednesday for MAZ020>024.
RI...Dense Fog Advisory until 6 AM EDT Wednesday for RIZ004>008.
MARINE...None.
&&
$$
SYNOPSIS...Nocera/Dunten
NEAR TERM...Frank
SHORT TERM...Nocera
LONG TERM...Dunten
AVIATION...Nocera/Dunten
MARINE...Nocera/Dunten
Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
724 PM CDT Tue May 29 2018
.AVIATION...
/00Z TAFs/
VFR, but thunderstorms may impact northern gates.
Intense convection is ongoing from the eastern Texas Panhandle and
northwestern Oklahoma, northward into the Central Plains. An
unseasonably strong (though not particularly moisture-rich) low-
level jet will feed these storms, allowing them to survive well
after nightfall. This inflow, combined with veering flow aloft,
may guide some of these cells into southern Oklahoma during the
early morning hours Wednesday. These convective elements will have
the tendency to become outflow-dominant during the predawn hours,
and although decent inflow will remain, they should undergo a
gradual diminishing trend as they approach the Red River. The
north departure corridor should be mostly clear by the morning
push, but impacts to arrivals through the Bonham cornerpost may
linger.
Convergence is negligible farther south along the West Texas
dryline, with only a few lethargic CU as sunset nears. This area
should remain quiet.
As a late season front invades the Southern Plains, winds will
increase and become more southerly Wednesday, maintaining this
breeziness Wednesday night. The only caveat is that outflow winds
could approach the Metroplex TAF sites early Wednesday, but at
this time, a wind shift appears unlikely.
25
&&
.SHORT TERM... /Issued 307 PM CDT Tue May 29 2018/
/Tonight/
A quiet night is expected overall, but part of a complex of
storms may move across our northeastern counties early Wednesday
morning.
This afternoon, a few storms may develop to the west and/or
northwest of Young County. The latest runs of the RAP and HRRR
keep this area free of storms, but if convection develops, their
natural tendency will be to move east towards our western
counties. This is still a small potential and do not have PoPs in
our western counties this evening, but will be keeping an eye on
the dryline to our west for the next several hours as this area is
weakly and/or uncapped and CAPE values have reached over 2500
J/kg.
The next area we will be monitoring is to our north where
afternoon and evening storms are expected to merge into a MCS
moving southeast overnight. An increasing low level jet will aid
in helping this complex maintain itself as it moves towards the
Red River, but if the outflow pushes too far ahead, the complex
may completely dissipate before reaching our counties. Between 4
am and 7 am is the most likely timeframe for showers and storms to
occur in our northeastern counties, generally along and northeast
of a Sherman to Sulphur Springs line, but also kept low PoPs
along the Red River towards Bowie. Gusty winds and lightning will
be the main hazards with any storms.
If an outflow boundary pushes into the region early Wednesday
morning, light north to east winds will occur behind the
boundary, and potentially some cooler morning temperatures.
JLDunn
&&
.LONG TERM... /Issued 307 PM CDT Tue May 29 2018/
/Wednesday Onward/
Hot and dry conditions will prevail through the extended portion
of the forecast with heat being the main concern for the next
several days.
An upper ridge remains in place across the southern US which is
contributing to dry weather with above normal or even near-record
temperatures. This will be the case again on Wednesday despite
parts of Central Texas starting the day with areas of low stratus
and parts of North Texas experiencing some cloud cover from a
decaying overnight complex of storms in Oklahoma. Heat index
values across our western zones may climb to 105F or higher
briefly Wednesday afternoon, and since this trend is expected to
continue on Thursday and Friday, a Heat Advisory may be needed as
early as tomorrow afternoon for areas including Graham,
Breckenridge, Mineral Wells, and other locations nearby.
Regardless, it will be hot area-wide for the foreseeable future
and preventative measures to avoid heat-related illness should be
taken seriously. A slight increase in southerly wind speeds (15-25
mph) may help the heat feel slightly less oppressive at times,
and may also make the century mark harder to obtain due to
increased mixing. Otherwise, the dryline will remain positioned to
our west throughout the rest of the week and will be capable of
initiating thunderstorms farther north and west where capping is
weaker. This convection and resultant complexes are expected to
remain north of the forecast area through Friday.
By Saturday, a weak cold front is expected to approach the region
from the north. However, those hoping for a blast of cool air to
drop our temperatures to near or below normal are sure to be
disappointed. Instead, compressional warming and moisture pooling
ahead of the front could potentially lead to a brutally hot and
humid Saturday afternoon with highs of 105-110 possible. Again,
for these conditions to occur, they will be contingent on an
afternoon/early evening arrival time of the front, and any
deviation would mean temperatures probably wouldn`t climb quite
that high. At this time, it appears there will only be a small
chance for a shower or storm along the front, and have left silent
10% PoPs at this time. The "cool down" is expected for Sunday
when high temperatures will (only) be in the 90s, but still above
normal for early June. Another warming trend will ensue to begin
next week with highs expected to climb back into the upper 90s or
low 100s with only low chances for rain.
-Stalley
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 77 98 76 99 76 / 5 5 5 0 0
Waco 74 98 76 98 76 / 0 0 10 0 0
Paris 72 95 74 94 74 / 40 10 5 5 0
Denton 74 99 76 98 76 / 10 5 5 0 0
McKinney 76 97 76 95 75 / 10 5 5 0 0
Dallas 79 98 77 99 77 / 5 5 5 0 0
Terrell 74 97 75 97 75 / 5 5 5 0 0
Corsicana 74 95 75 95 75 / 0 5 5 0 0
Temple 74 97 75 97 75 / 0 5 10 5 0
Mineral Wells 73 101 74 100 75 / 5 0 5 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
25/05
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
759 PM EDT Tue May 29 2018
.SYNOPSIS...
Deep tropical moisture will persist over the area through Wednesday
as the remnants of Alberto move northward from Alabama to Kentucky
and eventually to the Great Lakes. A moist airmass will persist into
Friday before southerly flow shifts more to the west. Slightly drier
air will mix in from the west over the weekend.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 745 PM EDT...Bands of heavy rain continue to slowly pivot
NEWD, oriented N-S. This is resulting in some training with intense,
tropical downpours that is causing flooding. No changes to the Flash
Flood Watch is needed at this time. Hopefully, with loss of daytime
heating, instability will decrease and rain rates will follow. The
latest HRRR shows gradual diminishing of precip across the eastern
half of the CWFA thru the evening, but then shows redevelopment of
scattered and hopefully, less intense, showers to the west that
spreads over the NC mountains thru the night. So categorical PoPs
will continue along the Blue Ridge overnight. The severe threat
looks to be lowering, due to decreasing instability and shear. So,
localized flooding and mountain landslides over the higher terrain
will continue to be the primary concern as periods of heavy rainfall
are expected to continue through the near term period. With the
already saturated ground, even marginal wind gusts could easily
bring down a few trees. High temperatures will remain near normal
and low temps will stay above normal.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 200 PM EDT Tuesday: By the start of the short term period
(Wednesday night), the remnant circulation of Alberto will be over
the midwest getting absorbed by a negatively-tilted shortwave trough
lifting out of the Northern Plains. Upper high in the western
Atlantic combined with the slowly merging Alberto/shortwave will
continue to keep a moist fetch from the Gulf across the Southeast
and toward the Southern Appalachians. The trough will slowly lift
through the period as the upper ridge works down over the Bahamas,
with the deep moisture lifting to the northeast as well. A lingering
shortwave embedded in the pattern will push up the OH/TN Valleys
Thursday night into Friday, bringing another push of precip to area.
At least at the start of the period, PW values remain anomalously
high with deep warm cloud processes. Keeping the Flash Flood Watch
in effect through 12z Thursday looks good for now, though the
additional round of convection Thursday afternoon across the
mountains might be enough to warrant another extension...confidence
just not high enough at this time with QPF in the 6-hr period from
18zThu-00zFri less than 1/2 inch (though with the antecedent
conditions, that might be all it takes). Problem is that instability
will increase, Thu afternoon, both the NAM and GFS are creeping
SBCAPEs upwards of 3000J/kg across the escarpment/foothills/adjacent
Piedmont which could seriously intensify convective rates.
That secondary wave of moisture gets caught up over the mountains
Thursday night into Friday morning and might have a slow start with
convective initiation initially across the Piedmont, but still
enough to increase afternoon Piedmont pops to high chance. Keep pops
going overnight across the mountains with likelies again by Friday
afternoon.
Should see a slow warming trend through the period, pushing 90 for a
high across the Piedmont by Friday afternoon and continued very
muggy (yuck)...heat indices might be pushing the mid-90s with the
dewpoints remaining quite high at around 70 degrees.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 155 PM Tuesday: A southern tier ridge centered over Texas
will try to briefly ridge into our region Friday night into
Saturday but make little progress. A weak surface frontal boundary
settles southward through the area to provide a very modest airmass
change. However, a digging northern stream trough will approach the
southern and central Appalachians Sunday and then cross the
mountains on Monday. This feature will enhance convection at a time
when CAPE values will be low on Monday. However, looking at Sunday
PM the GFS has 2000 to 3000 CAPE over the western tip of NC and the
upper Savannah Valley at the time when the EC has the axis of trough
crossing our region. Minor vortices crossing our area on Sunday
afternoon could spark strong convection over NE GA and adjacent
areas. Highest POPs Sunday and Monday along with warmer temps than
what we have had recently. Above climo maxes on Saturday will dip
below climo by Monday, but with mild nighttime mins continuing.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: An intense rain band with embedded tstms
oriented N-S across the GMU/GSP area continues to pivot
northeastward this evening. Widespread precip coverage ahead/east of
this line, but isolated to scattered to the west. There is still
enough instability for convection to linger into the evening, but
should gradually diminish in coverage overnight. Low cigs and some
fog is expected again overnight thru Wednesday morning, like the
last couple days. Little change in air mass for Wednesday aftn will
result in numerous showers and tstms again with peak heating, but
with slightly drier air starting to work in. CIGS should lift from
IFR to MVFR then scatter out somewhat to VFR by mid/late aftn. Winds
should favor a SE to S direction at all sites, but can be variable
at times around deeper convection.
Outlook: Expect continued rounds of scattered to widespread showers
and embedded thunderstorms along with low cigs and briefly reduced
vsbys as tropical moisture lingers through at midweek. Drier air begins
to move into the area towards the end of the week, with some degree
of diurnal convection expected.
Confidence Table...
00-06Z 06-12Z 12-18Z 18-00Z
KCLT High 90% High 88% High 94% High 100%
KGSP High 88% High 87% High 81% High 83%
KAVL High 89% High 91% High 90% High 84%
KHKY High 91% High 99% High 85% High 86%
KGMU High 80% High 84% High 93% High 83%
KAND Med 67% High 87% High 96% High 88%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.HYDROLOGY...
Heavy rainfall over the past two weeks across much of the forecast
area, particularly the mountains, has set the stage for serious
flooding and landslide issues to possibly develop with any
additional tropical rainfall through mid-week. Numerical model
profiles exhibiting precipitable water values of 1.75 to 2 inches,
and deep warm cloud layers in excess of 12 kft, will make for highly
efficient heavy rainfall processes and further increase the threat
of flash flooding and river flooding. The latest 3/6 hour FFG
guidance values are generally running 2.0 to 3.5 inches and these
will be quite achievable in the expected waves of tropical rain
showers - especially across the higher terrain. Hydro problems will
likely continue through tonight, and possibly through Wednesday
night across the mountains.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Flash Flood Watch through Thursday morning for GAZ010.
Flash Flood Watch through Wednesday morning for GAZ017-018-026-
028-029.
NC...Flash Flood Watch through Thursday morning for NCZ033-048>053-
058-059-062>065-501>510.
Flash Flood Watch through Wednesday morning for NCZ035>037-056-
057-068>072-082.
SC...Flash Flood Watch through Thursday morning for SCZ001>003.
Flash Flood Watch through Wednesday morning for SCZ004>014-019.
&&
$$
SYNOPSIS...DEO
NEAR TERM...ARK/JPT
SHORT TERM...JPT
LONG TERM...TDP
AVIATION...ARK
HYDROLOGY...
Area Forecast Discussion
National Weather Service Lincoln IL
910 PM CDT Tue May 29 2018
.UPDATE...
Issued at 910 PM CDT Tue May 29 2018
Rain band from decaying Alberto continues to move northwest across
the CWA this evening. Will be making some adjustment to pops for
the remainder of the night and tomorrow to account for new HiRes
solutions. Also will be adjusting overnight lows down 1 degree. Will
be sending an update shortly.
&&
.SHORT TERM...(This evening through Wednesday)
ISSUED AT 225 PM CDT Tue May 29 2018
Remnants of Alberto will continue to shift north into the Ohio
Valley late tonight with the associated rain shield edging into
southeast Illinois this evening and that band shifting north
into the remainder of the forecast area. The latest HRRR does
indicate a lull in the shower and thunderstorms across the east
late tonight but as the surface low shifts just north of the
Ohio Valley by Wednesday morning, it appears widespread showers
and isolated storms will shift north as well across most of the
area during the morning. Models have trended a bit further east
with the surface low tomorrow, as a result, the heaviest rainfall
looks to occur from extreme southeast IL into Indiana. Rainfall
totals in our area based on the latest track indicates around
one half inch across the west to 1.75 inches across parts of
southeast and east central Illinois. Local 2+ inch amounts not
out of the question across the southeast part of our forecast
area which will be closest to the surface low tomorrow morning.
Another warm and humid night tonight with lows around 70. Highs
on Wednesday cooler than today with afternoon temperatures mostly
in the 80s.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 225 PM CDT Tue May 29 2018
The shower threat holds, at least a scattered variety, into
Thursday with models showing some disagreement with the next wave
later Thursday into Thursday night. It appears the main baroclinic
boundary will be positions along the Ohio River and that is where
the ECMWF suggests the primary threat for scattered storms will
be later Thursday into Thursday night. Most of the latest models
have trended a bit further south with the boundary and rain chances
during this time period and we may see the POPs adjusted further
south as well over the next couple of runs if this trend continues.
Any shower threat in the south Thursday night into Friday should
move out as surface high pressure builds south Friday night into
Saturday before the next upper wave and frontal system tracks
into the Midwest Saturday night into Sunday morning. The upper
wave and surface boundary will bring another threat for scattered
thunderstorms to our area, especially Saturday night. After that
system pushes off to our east Sunday, the upper flow across the
area will be northwesterly with a mainly dry forecast into the
first week of June with above normal temperatures expected.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 650 PM CDT Tue May 29 2018
All sites will begin as VFR with light showers exiting the area to
the north. However the next band from Alberto is moving into
southeast IL and should reach DEC and CMI around 02z and then
continue northwest this evening reaching all the other sites. Not
seeing a lot of lightning in this band so will just have shra at
all sites with vis at 6sm. Going to keep this going through the
night and then bring either a strengthening of this band or
another band in the morning that could have more thunder in it.
Cigs with the morning band with drop to MVFR around 2kft. This
band will initially move northwest but during the day move east as
the system move east during the afternoon. Precip will end in the
afternoon and cigs should rise to VFR for the remainder of the TAF
period. Winds will be variable most of the period but become
westerly once the system moves east tomorrow afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Auten
SHORT TERM...Smith
LONG TERM...Smith
AVIATION...Auten
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1018 PM EDT Tue May 29 2018
.UPDATE...
Issued at 1018 PM EDT TUE MAY 29 2018
Based on the latest radar imagery, it appears that thunderstorm
activity has wound down for the night across eastern Kentucky.
Additional rain showers are expected to move across the area from
time to time overnight, so isolated to scattered showers were left
in the forecast in the latest update. The latest obs were ingested
into the forecast grids to establish new trends. Lastly, the
hazardous weather outlook was also updated to remove mention of
thunder for the rest of tonight. The updated forecast has already
been sent out.
UPDATE Issued at 733 PM EDT TUE MAY 29 2018
Ingested the latest obs into the forecast grids to establish new
trends and freshen up the data. Also removed the pre-first period
that the day shift included with the afternoon forecast package.
Will also update again later in the shift to remove mention of
thunder from the forecast once we`re sure thunder is done for the
night.
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 425 PM EDT TUE MAY 29 2018
19z sfc analysis shows the core remains of Alberto moving steadily
north into Tennessee with its cyclonic flow keeping the winds
easterly through Kentucky. This is helping to provide some
downsloping to eastern Kentucky likely slowing the convective
development thus far this afternoon. Some clearing in the north
for much of the day has allowed for a bit more instability to
develop there so that a few showers and thunderstorms are starting
to build across the central parts of the CWA. To the south,
lighter showers are found with a band that is dissipating -
expecting to be renewed later in the afternoon. Temperatures
currently vary from the low to mid 80s through the area, though
some 70s are noted in the far south where the clouds have been
thicker and more prevalent. Dewpoints remain very moist -
generally in the low 70s.
The models are in good agreement aloft through the short term
portion of the forecast. They all depict the dampening of the
upper low associated with Alberto`s remnants as it works north
through western Kentucky tonight and is absorbed into a northern
stream trough on Wednesday. This trough then slowly moves east
through the Great Lakes Wednesday night into Thursday morning.
While some energy will be co-located with the Alberto low - the
better perturbations will spread into the Ohio Valley from the
west later Wednesday into Thursday in the mainly flat flow post
Alberto. Given the model agreement will favor a general blend
though with a lean toward the higher resolution HRRR and NAM12
for weather details.
Sensible weather will feature a warm, muggy, and stormy short
term period as high PW air (2+ inches) in place is activated by
the passing of the upper low from Alberto and enough breaks in
the clouds for instability to build up. Although this moisture
will bring with it the potential for excessive rainfall, the
combination of downsloping into this evening and the progressive
nature of the individual storm cells throughout the period
precludes the need for a flash flood watch ATTM. However, any
eastward jog with the core of Alberto`s remains could change this
calculation. As it stands isolated pockets of excessive rains
will be possible through this evening and during the day
Wednesday. This will be mentioned in the HWO as well as
highlighted in the forthcoming weather story. Otherwise, very mild
temperatures will be had at night threatening some record high
low temperatures with warm conditions in place this afternoon and
Wednesday. Despite the moisture, will not anticipate much in the
way of fog owing to the cloud cover and lack of radiational
cooling each night.
Used the CONSShort and ShortBlend to kick start the grids through
the short term with minimal adjustments to temperatures given the
very moist environment. With the PoPs: kept them higher than
guidance for most of the time considering the high dewpoints and
synoptic situation.
.LONG TERM...(Thursday through Tuesday)
Issued at 355 PM EDT TUE MAY 29 2018
The long term upper level pattern will generally be dynamic with
progressive shortwaves moving over the region. Brief ridging looks
to set up Saturday night into Sunday and also on Tuesday, decreasing
precip chances over eastern Kentucky during these times. Looking
closer to the surface, a cold front over the Ohio Valley will push
southward on Friday. In addition, MUCAPE values are greatest on
Friday. Therefore, this will be the main source of precipitation for
the extended as well as the period where thunderstorm chances will
be the highest. However, periods of summertime afternoon/evening
shower and thunderstorms will be possible through early next week.
However, confidence is low for the later portion of the extended due
to model uncertainty.
Temperatures Thursday and Friday will be in the mid 80s, but then
decrease to be mainly in the low 80s after the passage of the cold
front. Low temperatures will be in the upper 60s through Friday,
then drop to be in the low 60s for the rest of the forecast period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
ISSUED AT 733 PM EDT TUE MAY 29 2018
The TAF period will feature isolated thunderstorms this evening
and then isolated to scattered rain showers overnight. The rain
will being to increase in coverage across the area by late
Wednesday morning, with scattered to numerous thunderstorms
possible across the area by early afternoon as the remnants of
Alberto move by to our west. Locally heavy rainfall and flooding
will be the primary threats with any storms. Conditions should
generally be VFR, but any given airport could experience MVFR or
worse conditions if a thunderstorms move directly over or near the
airport on Wednesday. Fog should be minimal overnight since cloud
cover is likely to remain BKN to OVC.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...GREIF
LONG TERM...CGAL
AVIATION...AR
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
855 PM CDT Tue May 29 2018
.UPDATE...
855 PM CDT
Updated to lower pops across the area this evening. Current weak
vort lobe wrapping northwest across the forecast area only
producing spotty sprinkles at this time, with diurnal loss of
stronger surface-based instability. Another round of weak
forcing, producing showers across central IL/IN at this time, will
spread into southern parts of the cwa toward/after midnight. with
rain chances increasing from the south into the pre-dawn hours.
Otherwise, no significant changes made.
Ratzer
&&
.SHORT TERM...
233 PM CDT
Through Wednesday...
A few rounds of showers and thunderstorms will be possible over the
next 24-36 hours associated with the remnants of Alberto lifting
north across the Tennessee Valley this afternoon.
Round 1...late this afternoon into the evening. Lead shortwave that
ejected northwest from the main circulations is lifting across
central Illinois as of about 200 pm CDT. Instability has been slow
to build through the day with cirrus canopy streaming overhead
through the day, but RAP analysis indicates that 1000-2000 J/kg
uncapped MLCAPE is in place across southern portions of the CWA. In
addition, surface obs show a decent area of convergence mainly
focused near the I-80 corridor. While an isolated shower/storm is
possible area-wide, the best chances will be near this low level
boundary this afternoon and within the better instability to the
south. Shear is too low to support any organized severe threat this
afternoon, but steep low level lapse rates/inverted V soundings do
support some threat for localized strong winds from collapsing
storms.
Round 2...late tonight into Wednesday morning. Next wave currently
in place over the lower Ohio Valley will lift north across the area
around/after midnight supporting additional showers with a few
thunderstorms into the early morning Wednesday. This next wave
should also usher in the leading edge of the very moist tropical air
mass with PWats rising in excess of two inches. Instability is more
limited overnight, but couldn`t rule out a few rumbles of thunder.
Heavy rain would be the main concern. Coverage should remain
scattered enough and convection progressive enough to limit any
flooding concern overnight.
Round 3...Wednesday afternoon. The main circulation from Alberto
will lift across Indiana through the day Wednesday. The projected
track of the low has been trending east with the latest model runs,
and there remains some uncertainty in specifics of where heavy
rainfall will set up Wednesday. It does appear that heavy rain will
still impact portions of northern Illinois and northwest Indiana.
Guidance has been suggesting that an arcing band of showers and
thunderstorms will pivot along a north/south axis. As this occurs,
there could be a window of training storms with very localized heavy
rainfall possible in excess of 2-3 inches. For now, this would be
favored somewhere near the I-39 corridor late morning into the
afternoon. Meanwhile, the most concentrated precip coverage will be
closer to the low favoring far eastern/northeast portions in
Illinois and northwest Indiana. Heavier rainfall of 1-3 inches is
more likely in this area with localized heavier amounts possible.
The low will lift into Michigan during the evening with the
precip threat winding down across the local CWA.
Deubelbeiss
&&
.LONG TERM...
233 PM CDT
Wednesday night through Tuesday...
The peak moisture transport associated with subtropical storm
Alberto will pull off to the northeast as the main upper level
circulation will weaken. Our focus will then shift to another
circulation currently over the high plains along with southern
stream energy across the southwest on the back side of a
widespread ridge over Mexico. It does appear that these two
sources of lift will largely pass by both to our north and south
on Thursday. Deep tropical moisture will exit the area with
Alberto in spite of pronounced west-southwest flow maintaining a
feed of elevated dewpoint air across the region. Still with the
northern stream low driving a surface boundary and some pooling of
lower level moisture, some isolated thunderstorms do remain a
possibility Thursday afternoon and evening. A very warm airmass
will again be in place with highs expected to surge back to around
90, even higher possible south if clouds are thinner. With 60s
dewpoints, this makes for low to mid 90s for heat indices. With a
surface boundary expected to move through, the warming should be
realized at the lake given a stronger westerly wind component.
The northern stream low will then slowly dampen across the western
Great Lakes on Friday. Model guidance is in fair agreement in
driving a backdoor cold front across the lakefront areas Friday
morning and across the remainder of the area late in the day. Most
guidance is dry with the frontal passage, but could not rule out
an isolated shower.
An upper ridge will briefly transit the lower Great Lakes Friday
night into Saturday, with high pressure expected to setup over the
northern lakes. This will shift our level flow around to the
northeast, a cooler and drier direction. There is a pacific
shortwave that will arrive quickly on the heels of the ridge, but
appears to move into a fairly stable dry airmass, therefore at
this point much of Saturday will be dry with increasing clouds. If
we get any precip, it would come Saturday night. The more
seasonal pattern will continue into early next week with high
pressure in place and northeast flow. This pattern will also
feature cooler conditions at the lake.
KMD
&&
.AVIATION...
For the 00Z TAFs...
Main aviation concerns involve timing rounds of showers, and
thunderstorms especially late tonight through Wednesday, as the
remnants of Alberto lift across the region.
Circulation associated with Alberto was over the lower Mississippi
Valley early this evening, though a series of weaker mid-level
short waves were wrapping north-northwestward in advance of the
main system. One such weak wave will pass across the area early
this evening, with small isolated to scattered showers noted over
Lake Michigan and the Chicago area. Forecast soundings indicate
some elevated instability across the area, though onshore winds
off the lake will likely limit the thunder potential with these
across the Chicago area. Next stronger wave approaches overnight,
with rain potential ramping up 08-10Z. While embedded thunder is
possible, forecast soundings indicate deep moist profile with
limited instability late tonight/Wednesday morning. May see a
break in the more persistent rain showers by mid-late morning
Wednesday, before showers and a better potential for thunderstorms
develop again during the afternoon. MVFR vsbys and ceilings are
likely at times during periods of rain, though brief IFR
visibility reductions are possible. Rain should lift out to the
northeast early Wednesday evening.
Surface winds will be generally east-northeasterly through
Wednesday morning, eventually shifting more south-southeast as the
surface trough approaches toward mid-day. Winds then will veer to
the west-southwest in the afternoon as the trough lifts north.
Ratzer
&&
.MARINE...
233 PM CDT
An expansive high will reach west central Quebec today setting
the stage for northeast to east winds across the lake. Meanwhile,
two areas of low pressure will approach the western Great Lakes
by midweek. The remnants of Subtropical Storm Alberto will lift
from the Tennessee Valley tonight to lower Michigan late
Wednesday filling as it lifts north. Another low will move from
the Dakotas this afternoon to the Upper Midwest Wednesday night
into Thursday. There is considerable uncertainty in the winds
between these features around midweek, though in general winds
should be light. The northern low will track across Lake Michigan
by late in the week with moderately strong northerly winds gusting
25 to 30 kt in its wake. These winds will first reach the north
half of the lake Thursday, with the front is progged to reach the
southern tip of Lake Michigan around or shortly after daybreak
Friday. Expect waves to approach 4-5 ft on the south half such
that small craft advisory conditions may at least temporarily be
met. High pressure spreads over the lake Sunday which will allow
weaker though continued northeast winds to persist through the
weekend.
KMD/JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
National Weather Service Melbourne FL
934 PM EDT Tue May 29 2018
.UPDATE...
Tonight...Afternoon showers/storms had more coverage today across
about the north half of the area. That activity has lifted north
and was diminishing. The HRRR model still suggests an area of
showers moving up from the south overnight and the 18z GFS also
showed that happening.
Isolated convection recently developed over the Everglades. Our
southern areas were largely skipped by daytime showers/storms, while
the local WRF model trended to some precip occurring overnight. Will
follow trends as we may need chance PoPs overnight, especially in
the south. Otherwise, will keep the 20 percent chance of showers
that is in the current forecast.
&&
.AVIATION...
Considerable debris cloudiness will again stream over the area
tonight. The last set of TAFs discounted showers moving up from the
south like some of the models have been showing. The next set of
TAFs will have to take another look at overnight shower chances as
well as patchy MVFR ceilings.
High moisture and boundary interactions on Wed will generate another
round of scattered/numerous afternoon convection. Timing and
location should again be difficult to pin down due to areas of
mid/high level debris clouds.
&&
.MARINE...
Tonight-Wednesday...Axis of Atlantic ridge will extend across
central Florida and provide a southerly wind flow. The models show
the gradient supporting about 10 knots, but periods of 10-15 knots
are possible, especially offshore. Seas are forecast to be 2-3 feet
on Wed. Enough southwest steering level flow may push a few
afternoon storms across the coast and produce gusty winds to around
35 knots.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&
$$
Lascody/Ulrich/Negron
Area Forecast Discussion
National Weather Service Marquette MI
745 PM EDT Tue May 29 2018
.SHORT TERM...(This evening through Wednesday)
Issued at 416 PM EDT TUE MAY 29 2018
Water vapor imagery and RAP analysis show a mid-level low centered
along the WY/SD border and subtropical depression Alberto centered
over nw AL. To the n and e of these features, rather pronounced mid-
level ridge extends from the Upper Lakes se to a subtropical high
off the se coast. This sharp ridge has maintained dry weather across
the fcst area this aftn. Even cu has failed to develop. So, its been
a mainly sunny day with only thin high clouds passing at times.
Temps have soared well into the 80s over the interior w half. Sharp
cooling is noted along Lake Superior where lake breeze has slipped
inland. Some shoreline locations have only seen temps in the 40s
today.
Tonight, the mid-level low currently along the WY/SD border will
drift across the Dakotas. Meanwhile, remnant of subtropical storm
Alberto will lift to the Lower Ohio Valley. Although pronounced mid-
level ridge axis across the Upper Lakes will rotate ne, low-level
jet axis in response to the Plains system will remain focused no
farther e than MN. As a result, do not anticipate any of the
convection currently developing in MN to reach Upper MI tonight.
On Wed, mid-level low over the Dakotas will tend to open up as it
moves to MN. Meanwhile, remnant of Alberto will lift toward sw Lwr
MI. Deep layer forcing and increasing upper diffluence will lead to
shra and some tsra development thru the day, beginning first over
the w where there should be sufficient daytime heating to build
instability and aid shra development. Deep tropical moisture lifting
n ahead of the trof and in association with the subtropical remnant
will bring precipitable water up to 1.75 to 2 inches, roughly 275-
300pct of normal, by evening across Upper MI, which would be record
or near record values for this time of year based on INL/APX/GRB
sounding climo. Combined with freezing level increasing to around
12kft, potential will be there for very heavy downpours with some of
the shra/tsra. Increasing clouds will put the breaks on heating and
instability buildup on Wed, but it appears mlcape may increase to
1000j/kg or so before that happens. With deep layer shear under
25kt, do not anticipate any svr storms. Deep layer shear does
increase some during the aftn, but by then, instability will be
waning. If there are any stronger storms, they would occur early in
the aftn.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 257 PM EDT TUE MAY 29 2018
Nam shows a shortwave over the upper Great Lakes 00z Thu with a
trough over the west coast. The shortwave affects the area Wed night
into Thu and then a shortwave ridge builds in for Fri. Did not make
too many changes to the going forecast overall.
In the extended, GFS and ECMWF show a 500 mb shortwave ridge over
the upper Great Lakes 12z Sat with a shortwave over the northern
plains. This shortwave moves through on Sun and brings a cold front
through the area. GFS keeps more upper ridging into the upper Great
Lakes 12z Mon while the ECMWF has a broad trough over the area which
remains into Tue. Temperatures will start out near normal and then
warm to slightly above normal for this forecast period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 737 PM EDT TUE MAY 29 2018
Convective activity currently blanketing much of eastern MN into
far western WI is expected to remain west of KIWD and the other
two terminals. Therefore, VFR conditions are anticipated to
prevail through the overnight hours. For tomorrow, as the Upper
Peninsula enters into a more active pattern and copious amounts
of atmospheric moisture starts advecting into the region, look for
the possibility of showers and thunderstorms to start creeping
into the western portions of the U.P. by around midday. Any
showers and storms that do develop could contain moderate to heavy
rain, briefly reducing visbys. KCMX and KSAW currently look to
remain dry through this TAF period, but will see increasing
chances by the tail end of the period. Southerly to southeasterly
winds will prevail with gusts possible tomorrow, particularly at
KSAW.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 416 PM EDT TUE MAY 29 2018
A low pres system will reach the Upper Great Lakes on Thu. Ahead of
it, winds should be under 20kt thru Thu. However, gusts at higher
obs platforms will reach 25kt at times. As the low departs and high
pres builds over southern Hudson Bay, winds will increase to 15-25kt
across much of Lake Superior Thu night and Fri. Winds will then
diminish to mostly under 15kt over the weekend.
While fog has dissipated on Lake Superior, shra Wed and Thu may lead
to fog redevelopment, potentially dense fog. If fog develops, it
will dissipate under strengthening n to ne winds and influx of
much drier air Thu night.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...07
AVIATION...lg
MARINE...Rolfson
Area Forecast Discussion
National Weather Service Paducah KY
741 PM CDT Tue May 29 2018
.UPDATE...
Issued at 741 PM CDT Tue May 29 2018
The center of Alberto is currently about 125 miles east northeast
of Memphis, TN. We continue to see rain bands spiraling around
this circulation bringing some very heavy rain at times. Rainfall
rates with the heaviest cells reached upwards of an inch per hour.
Latest HRRR/RAP models indicate Alberto will continue wobbling
northward and be crossing into west KY by around 06Z. We will
continue to see bands of rain rotate through this evening but
when the actual circulation approaches late tonight, we will also
see a more concentrated area of rain move up into western KY
during the 06Z-09Z period, then lifting north and east toward 12Z.
Have adjusted POPs through the evening/overnight hours to reflect
latest thinking. Still looks like highest rainfall totals will be
over western KY, up into parts of southern IL and southwest IN
with 2-3 inches likely...locally higher amounts possible. Quite a
gradient though as you head westward, where parts of the Ozarks
foothills may not get much at all. Winds will also be picking up
as the circulation approaches later tonight.
&&
.SHORT TERM...(Tonight through Thursday night)
Issued at 137 PM CDT Tue May 29 2018
OHX 12Z Sounding showed PWats at 1.86". NAM is modeling PWats
pretty good, and has them increasing to 2" plus, this
evening/overnight. HRRR perhaps has best near term handle on Pops.
A combo of its radar modeling with the NAM suggests categorical
best Pops and QPF (WPC QPF per collab) are matched up well/best
with our current FFA, so will leave headlines alone and make the
necessary minor gridded adjustments for the latest data. Some
consideration to extending the Watch past 12z (perhaps 15z) can
probably best be decided in a later shift, given Alberto is still
working its way out of Bamaland.
New storm total qpf will include Wed, even though FFA will expire
that morning. It won`t make much difference on the max QPF path or
amounts, which will effectively be in the 2-3" range. The Watch is
basically inclusive of the 1-3" range, which while these amounts
don`t necessarily exceed FFG, locally higher (sub)tropical Alberto
remnant totals may cause localized (flash) flooding problems. The
Watch is well collaborated, as is the convective threat. That is,
there won`t be much of one after sunset today, visa vi the usual
tropical impact. However, we`ll still carry a slight chance
mention of thunder with the highest pops and Alberto`s lift track
overnight tonight.
After Alberto`s lift out Wed., we`ll have a brief pause and then a
strong warmup heading into Thursday. This warmup will yield an
unstable lower trop parcel environ as mid level winds increase
with incoming ripples of energy, that will result in a slgt risk
of severe storms Thu pm/evening. We`ll see how Wed boundaries and
atmos recovery evolves post Alberto though, before getting too
excited about the Day 3 probs. Thursday HI`s could still reach
thru the 90s, approaching triple digits in the Delta far SEMO/far
SWKY.
.LONG TERM...(Friday through Monday)
Issued at 322 PM CDT Tue May 29 2018
The medium range models and the GEFS/ECENES means were in reasonable
agreement overall, but individual member variability increased and
run-to-run consistency decreased after about Day 5.
At the start of the extended forecast period (Fri night), drier air
should be able to filter into the PAH forecast area under
northwesterly winds aloft, as flow aloft over the Mid-Atlantic
region becomes more cyclonic and sluggish. However, moisture is
generally progged to surge back into our region as low level winds
turn back to the southwest early Sat, just ahead of a mid level
shear axis impinging on a central U.S. ridge. This will likely
result in heat indices in excess of 100 in the Purchase area of KY
and most of southeastern MO Fri and Sat.
The deterministic model solutions were in fairly good agreement that
some shower and tstm activity associated with the feature and its
surface reflection will peak Sat night in our region. However, in
contrast to the ECMWF/CMC, the GFS showed the mid level feature
slowing and actually closing into a low as it moves southeastward,
inducing double-barreled surface lows. This caused the
initialization blend to have PoPs lingering through Sun, instead of
rapidly dropping off. Due to the aforementioned variability, the
forecast at this time frame will be subject to change. One thing
more certain is that, under general high surface pressure, Sun
through Tue will probably have modestly cooler temps, with dewpoints
back in the 60s.
&&
.AVIATION...
Issued at 637 PM CDT Tue May 29 2018
Bands of showers and occasional thunderstorms are rotating around
the remnants of Alberto, which is steadily heading north toward
the area. We will continue to see these bands of rain throughout
the evening, but as the center of Alberto moves into the immediate
area during the overnight hours into early Wednesday morning, we
will see winds pick up and the intensity of rain increase. Cigs
and vsbys will temporarily lower to MVFR or lower with the bands
this evening, but there will eventually be a period of time late
tonight, where low cigs/vsbys along with heavier rainfall will be
likely, especially at KPAH/KEVV/KOWB. Winds will vary from east to
north ahead of Alberto`s approach and shift around to south or
southwest in its wake. Eastern terminals (KOWB/KEVV) will see
higher winds with gusts into/thru the 20s possible.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Flash Flood Watch through Wednesday morning for ILZ075>078-
080>094.
MO...Flash Flood Watch through Wednesday morning for MOZ076-087-111-
112.
IN...Flash Flood Watch through Wednesday morning for INZ081-082-
085>088.
KY...Flash Flood Watch through Wednesday morning for KYZ001>022.
&&
$$
Area Forecast Discussion
National Weather Service Pueblo CO
331 PM MDT Tue May 29 2018
.SHORT TERM...(This evening through Wednesday)
Issued at 246 PM MDT Tue May 29 2018
Convection which initiated along the Palmer Divide earlier this
afternoon diving E-SE across the plains as of 21z, and with CAPES
running 1500-2000 J/KG, potential for a strong/severe storm or two
will continue north of the Arkansas River from La Junta eastward
into the evening. Will keep some lower pops farther west across El
Paso county until around sunset as well, as last few runs of the
HRRR redevelop some weak convection in the area, though confidence
is rather low given marginal instability. Storms clear the area
quickly this evening, with dry conditions overnight, though some
brief stratus may develop over the eastern plains toward sunrise.
On Wednesday, thunderstorm chances increase across the region as low
level moisture pushes westward toward the mountains, and upper level
wave lifts from AZ into nrn NM during the day. Best forcing and wind
shear for severe convection will be found over the eastern plains
south of the Arkansas River, with weaker shear but better low level
moisture convergence farther north near the Palmer Divide. Overall,
broadbrush of pops over the region looks fine, with marginal SWODY2
covering the eastern plains looking reasonable. Mountains should see
an upturn in convection as well, though with dry low levels precip
amounts over the higher terrain/interior valleys will be light. Max
temps most locations will creep upward a few degf as mid levels warm
slightly.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 246 PM MDT Tue May 29 2018
Models continue to be in general agreement through much of the
extended period along with modest ensemble spreads. Fire weather
will be of concern Thursday into Friday, while increased potential
for showers and thunderstorms will round out the extended period.
Wednesday night...expect showers and thunderstorms to be ongoing
Wednesday evening along the Continental Divide which will
dissipate with sunset. Elsewhere, more isolated thunderstorms are
expected over the Palmer Divide and Baca County which will shift
east and dissipate through the overnight hours. Thunderstorms will
be capable of lightning and possibly small hail.
Thursday through Saturday...concerns turn to fire weather Thursday
and especially Friday. An upper level trough is forecast to move
east into the Great Basin on Thursday with increasing southwest
flow across Colorado. This will lead to elevated fire weather
concerns, especially for the San Luis Valley, and areas along the
New Mexico border due to gusty winds and low humidity values.
Mixing will also allow for afternoon high temperatures to reach
into the mid 90s. The upper trough will lift northeast on Friday
with the base moving across southern Colorado. Expect flow aloft
to further increase across the area by Friday mid morning. This
will be the most critical fire weather day, with strong winds and
low humidity values across all of southern Colorado. Any outdoor
burning should be postponed and burn bans followed on Friday.
Temperatures will continue to be hot, with highs in the 90s and
perhaps a few low 100s across the Plains. As the upper disturbance
lifts away from the area, a cold front will drop south across the
Plains by Saturday morning. This will bring slightly cooler highs
to the area with 80s over the Plains. Northwesterly flow will also
bring better humidity recoveries to the area with reduced fire
weather concerns through the day.
Sunday through Tuesday...continued southwest flow with embedded
energy will remain in place across southern Colorado through this
period. This will bring increased moisture and better chances for
showers and thunderstorms to the area, especially on Sunday and
Monday. Temperatures will remain on the cooler side as well, with
generally 80s for highs across the lower elevations. Much is
dependent on when the embedded energy moves across the state as to
when better chances for thunderstorms are expected. Mozley
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 246 PM MDT Tue May 29 2018
First wave of convection has moved east of KCOS as of 21z, though
HRRR suggests another round of tsra possible 23z-01z, as modest
instability and old outflow boundary remain in place, and will keep
VCTS mention going for into early evening. At KPUB, outflow boundary
will switch the winds to a more nly component by 00z, though appears
instability will be lacking for any tsra development and will keep
mention out of the TAF. KALS will remain convection free as mountain
storms have been lacking so far today. Overnight, VFR at all
terminals, with a brief period of stratus possible toward 12z on the
eastern plains east of KCOS/KPUB. On Wednesday, increasing chances
for tsra at all terminals after 18z, best chances at KPUB and
KCOS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PETERSEN
LONG TERM...MOZLEY
AVIATION...PETERSEN