Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/21/18
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
946 PM CDT Fri Apr 20 2018
.DISCUSSION...Modified wind speeds using SREF guidance being
closer to current slight increase especially over the Gulf waters.
The winds are approaching SCA over the near shore waters. But SREF
along with latest HRRR model showed winds will decrease slightly
later tonight and remain at SCEC levels. SREF models shows the
winds may increase again during the day Saturday close to SCA
levels over the Gulf waters and southern bays. No other changes
were made to the current forecast.
.PREVIOUS DISCUSSION... /Issued 648 PM CDT Fri Apr 20 2018/
DISCUSSION...See Aviation section for 00Z TAFs.
AVIATION...MVFR ceilings over portions of the Coastal Bend at
this time is expected to become prevalent early this evening.
Expect MVFR ceilings will reach inland areas from VCT to LRD
between 08-09Z. MVFR ceilings will remain over South Texas through
the rest of the night into Saturday. Southerly low level flow of
30 knots will increase the low level moisture by Saturday morning.
Isolated showers in the morning is expected to increase in
coverage to scattered over the coastal plains in the afternoon.
Model forecast soundings indicate the mid level inversion will
remain strong over the region with a very limited threat for deep
convection. TEMPO or PROB30 groups for showers over the coastal
plains in the afternoon with better chances in the VCT area.
Southeast winds will be gusty along the coast as a surface low
moves east across north central Texas in the afternoon.
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 67 79 65 82 60 / 10 40 20 10 10
Victoria 63 77 62 78 55 / 20 50 40 10 0
Laredo 67 85 65 86 64 / 10 20 10 0 10
Alice 66 81 64 84 58 / 10 40 20 10 10
Rockport 68 78 67 78 61 / 20 40 30 10 0
Cotulla 65 83 62 83 59 / 20 20 10 0 10
Kingsville 67 81 66 85 59 / 10 40 20 10 10
Navy Corpus 70 79 68 80 64 / 10 40 20 10 10
Area Forecast Discussion
National Weather Service Phoenix AZ
233 PM MST Fri Apr 20 2018
An exiting weather system today will bring breezy conditions with
warming conditions west of Phoenix. Building high pressure this
weekend will result in a significant warming trend with high
temperatures reaching into the middle 90s by Monday. The very
warm and dry conditions will last through the middle of next week
with highs nearing 100 degrees over the warmest desert locations.
An upper low was centered near the 4 Corners early this afternoon
which has kept lingering breeziness going and enabled some
additional cool air to filer eastern portions of the forecast area
(including metro Phoenix). Some modest instability is evident in
the cloud cover affecting much of northern Arizona. There are even some
weak radar echoes there. A short wave on the western side of the
low is evident in the water vapor imagery and is well depicted in
the models. HRRR and some other hi-res guidance depict increased
coverage of radar echoes as it swings southeastward late this
afternoon and evening. Precip chances for our forecast will be
slight and limited to portions of southern Gila County.
Transient ridging tracks across the western states over the
weekend for a warming trend. Of note there is a split in the
Westerlies far offshore which will enable a weak short wave to
undercut the ridge on Sunday. This will produce little more than
thick high clouds. By Tuesday, the flow consolidates as a low
deepens off the West Coast. Expect some more high cloudiness
emanating from subtropical latitudes. Temperature guidance in
pretty good agreement that highs will still be well into the 90s.
Substantial model spread is seen across the Southwest U.S. for
the latter half of next week. Overall model consensus shows a deep
upper level low potentially becoming cut-off from the main flow
during the period. Very little change is seen across the Desert
Southwest for next Wednesday with continued very warm temperatures
and dry conditions. Forecast confidence is low thereafter as
temperatures will be highly dependent on how long the upper low
sits off the West Coast. For now it looks like the well above
normal temperatures are to remain over the region through at least
next Thursday, possibly longer.
South-Central Arizona including KPHX, KIWA, and KSDL:
Breezy westerly winds will once again be present today. Through
sunset, wind speeds will be around 10 to 15 kts with gusts up to
20 kts. Winds will return back to a light diurnal regime
overnight tonight. Skies will be clear.
Southeast California/Southwest Arizona including KIPL and
At KIPL, winds will be out of the northwest aob 5 kts through
sunset. Thereafter, winds will generally become light and variable
but primarily hold on to a west-southwest wind direction. At KBLH,
winds will be out of the southwest with some breeziness up to 20
kts possible through sunset. Thereafter, speeds will reduce
significantly, becoming light and variable by 10Z. Skies will
remain clear at both TAF sites through the period.
Aviation Discussion not updated for amended TAFs.
Sunday through Friday...
A pattern of warm and dry weather will predominate the region
throughout the period. Above normal max temps in the 90s and min RH
values in the single digits are expected to persist through
Friday. Overnight recovery is expected to remain poor to fair.
Otherwise generally light winds with occasional seasonable breezes
can be expected through midweek next week. Strengthening
breeziness is anticipated late next week.
.SPOTTER INFORMATION STATEMENT...
Spotters are encouraged to follow standard reporting procedures.
Area Forecast Discussion
National Weather Service Charleston WV
1031 PM EDT Fri Apr 20 2018
High pressure through the weekend. Next system arrives Monday
.NEAR TERM /THROUGH SATURDAY/...
As of 1030 PM Friday...
Adjusted hourly temperatures per latest sfc obs and HRRR model.
Rest of forecast remains representative.
As of 115 PM Friday...
High pressure remains in place through the near-term with clear
skies and dry conditions. Northwesterly winds continue today and
gradually lessen to light and variable over night. This combined
with clear skies and dewpoints below freezing indicate a good
radiational cooling night especially in sheltered valleys. As a
result, have followed the low-end of temperature guidance and
decreased incised valleys an additional degree or two to account
for this. This of course is a 2 meter temperature and extra
consideration should be taken by users for potentially lower
near-ground temperatures affecting vegetation.
As a result a Freeze Warning has been posted for most of the
area where the grow season has been included, with a frost
advisory covering the remaining zones. This now includes
Dickenson (frost), Buchanan (freeze) in VA and Wyoming, McDowell
(both freeze) in southern WV. NE KY, Lawrence OH, and Wayne WV
are also under a frost advisory.
Very dry air lurks just aloft, but low-level weak winds
especially tonight and tomorrow make it tough to mix these lower
values down to the surface especially as winds decrease through
tomorrow. However, it bears watching as there have been
localized low dew points observed today where mixing is
evidently happening. Current forecast indicates minRH in the
mid- to upper-20`s today with slightly lower minRH in the low-
to mid-20`s tomorrow with greater afternoon warming.
High cirrus clouds start to creep in from the WNW Saturday
afternoon ahead of a ridge aloft.
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 225 PM Friday...
Upper-level ridge builds over area early in the period and
remains in place into Monday. At the surface, an area of low
pressure will push east across the lower Mississippi River
valley into the southeastern states.
Dry weather Saturday night into Sunday will give way to
precipitation chances increasing from the southwest late Sunday
night into Monday.
Temperature guidance looks good and was generally followed.
Readings should be near normal through the period.
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 225 PM Friday...
Upper level systems and a cold front pushing east will result in
unsettled weather through the period. As a result, expect
daytime temperatures will be below normal.
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
As of 735 PM Friday...
High pressure continues to build over the region providing
clear skies and light to calm flow. Widespread VFR conditions
through the period.
A low pressure system in the southern stream will approach from
the southwest Sunday night bringing pcpn spreading from south
to north on Monday. MVFR conditions expected under light rain
becoming with periods of IFR Monday night.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY...
FORECAST CONFIDENCE: High.
ALTERNATE SCENARIOS: MVFR/IFR possible should BR/FG occur
tonight, however fog formation is unlikely at this time.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 04/21/18
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY H H H H H H H H H H H M
HTS CONSISTENCY H H H H H H H H H H H M
BKW CONSISTENCY H H H H H H H H H H H M
EKN CONSISTENCY H H H H H H H H H H H L
PKB CONSISTENCY H H H H H H H H H H H M
CKB CONSISTENCY H H H H H H H H H H H M
AFTER 00Z SUNDAY...
IFR conditions possible Monday and Monday night under moderate
WV...Freeze Warning until 10 AM EDT Saturday for WVZ006>011-013>020-
Frost Advisory until 10 AM EDT Saturday for WVZ005.
OH...Freeze Warning until 10 AM EDT Saturday for OHZ066-067-075-076-
Frost Advisory until 10 AM EDT Saturday for OHZ087.
KY...Frost Advisory until 10 AM EDT Saturday for KYZ101>103-105.
VA...Freeze Warning until 10 AM EDT Saturday for VAZ004.
Frost Advisory until 10 AM EDT Saturday for VAZ003.