Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Albuquerque nm
547 PM MDT Thursday Aug 21 2014
00z taf cycle
moderate to high impact period for aviation the next 24 hours. A
well defined upper wave sliding slowly east over Arizona is dragging
a deep fetch of moist southerly flow north into nm. Showers and
a few storms are breaking out west of the continue dvd and over far
southern nm. This activity will move slowly north and expected
to merge into a large area of rain late tonight through Friday
morning. Cloud decks will lower from SW to NE and approach 040
around sunrise in areas from kabq west to kgup southward. This
will be accompanied by rain...occasional visibility reductions near
6sm...and Montana top obscurations. Area of rain will dissipate as it
shifts east through 20z...then redevelop into scattered storms by
middle to late day. The coverage of the convective activity is in
question depending on the amount of heating that can develop
behind the departing cloud shield.
Previous discussion...342 PM MDT Thursday Aug 21 2014...
monsoon moisture will surge into New Mexico from the west and south
tonight as an upper low over Southern California lifts northeastward
through Arizona. Cloudy to mostly cloudy skies along with scattered
to numerous showers and thunderstorms will result Friday. A drier
and much more stable airmass will quickly replace the moisture
Saturday and Sunday...with much less...if any thunderstorm
activity. Monsoon moisture will seep back in from the south early
next week...leading to a gradual uptick in thunderstorms activity
Monday through Thursday. Temperatures will be near average for
closed upper low center now just south of Needles California this afternoon
and now showing signs of lifting northeastward. Mainly high level plume of
moisture continues to Peel off of category 1 Hurricane Lowell. And
into the southwesterly flow ahead of the low. Models indicating the main
moisture surge for nm will be from Chihuahua as the middle- level southerly
flow between the weakening upper low and subtropical high over the
deep south increases.
Nam12 and local WRF are in good agreement that showers and storms
will break out late this afternoon or early evening over the
Southwest Mountains north to west-central areas. Later tonight...another
band of showers and thunderstorms will move northward up the Rio
Grande early Friday morning. Increasing slwy winds aloft will
combine with surface convergence to generate a line of thunderstorms
from the crest of the Central Mountain chain east into the the
central and northeast Highlands from late morning through early
afternoon. A few strong storms area likely as strong upper
diffluence moves over nm ahead of the now open upper level wave
lifting northeastward. Models indicating that western areas will get into
the act Friday afternoon will a line of thunderstorms along and
near The Divide from near dusty north to Dulce. Additionally...strengthening
surface low over southeast Colorado will help generate scattered to numerous
orographically enhanced showers and thunderstorms along the west
facing slopes of the sangre Delaware cristos as 35kt west winds combine
with high dewpoints and increasing instability. Will forgo Flash
Flood Watch as flow near above mountain top level remains southerly
and not cross barrier which will allow storms to move off the
Quite the contrast expected for the weekend as strong subsidence
moves over northern and central New Mexico Saturday in the wake of
the upper low. Lots of fair weather cumulus expected with perhaps
a short-lived thunderstorm over the northern mountains. Middle level
begins to creep back into southern areas Sunday. Best chances for
isolated activity will be over the SW and SC mountains Sunday
afternoon and early evening. Middle level monsoon moisture continues
to seep northward Monday with slightly more activity thanks in
part to a weak upper level wave/speed maximum.
Confidence beyond Monday night remains quite low as GFS and European model (ecmwf)
starting to converge on a similar solution but not quite there
just yet. GFS is the much drier solutions with northwest flow aloft
developing late Tuesday and continue until at least Thursday.
Northward flowing moisture along with an approaching upper level
system will initiate isolated to scattered showers and thunderstorms
for western areas the rest of this afternoon. Wetting storm coverage
will increase and progress eastward impacting central areas
overnight into Friday. Wetting rain coverage will lessen during the
weekend as drier air moves in from the west.
Late afternoon to early evening showers and thunderstorms will favor
western areas expanding into the northern mountains and Rio Grande
Valley tonight. Look for any developing storms to move
east-northeast between 10 to 15 miles per hour. A few spotty but limited
isolated showers could develop over the eastern plains late tonight
as well. Because of Lee side troughing east of the mountain
chain...expect breezy gusts near 25 miles per hour in some spots.
Showers with embedded thunderstorms will continue across the Rio
Grande Valley Friday morning as the upper level trough clips the
northwest corner of the state. During Friday afternoon and evening
hours...wetting storm coverage will be focused along and east of
the Central Mountain chain. High temperatures will drop at least 10 to
12 degrees area wide because of cloud cover and precipitation.
Central and western areas will be 10 to 15 degrees below average.
The extreme east will be near normal because of Lee troughing
boosting wind speeds...possibly to windy categories by the
afternoon. Relative humidity values will increase area wide.
The upper level trough looks to exit to the east Friday night.
Increasing westerly flow and drier air will follow the trough and
impact the area during the weekend. Storm activity will be limited
along with increasing temperatures...although still below average in
some places. The best chance for residual wetting rain would be
found across the southern tier due to focused lift and some left
over monsoonal moisture. Some slight model difference however.
Models differences come more into play by the middle of next week.
This is especially so with run to run model consistency. The
GFS and ecwmf are now more consistent with their morning solutions.
They have an upper level trough to our north and it is more
progressive thus a little drier for the area. The Canadian model is
slower with the upper trough and mimics yesterday evening/S European model (ecmwf).
The slower/deeper progression to the trough means better potential
for monsoonal moisture reaching the area. The one caveat is that
both European model (ecmwf)/GFS show some sort of back door cold front influence
which could enhance precipitation across central/eastern areas
midweek. Will continue to monitor and look for more consistency
amongst the models...both run to run and within the run.