Area Forecast Discussion
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FXUS64 KLUB 262321 AAA

Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
521 PM CST Sun Feb 26 2017

VFR conditions through the next 24 hours.  Jordan


.PREV DISCUSSION... /issued 335 PM CST Sun Feb 26 2017/

Mid and upper level cloud coverage has steadily increased from the
west throughout the day while surface winds gradually backed from
northwest to southwest on the Caprock and have remained mostly light
and variable off the Caprock in the Rolling Plains. Overnight lows
tonight will be similar or a tad warmer than last night with
increased cloud cover and slightly higher surface dew points. Could
see some patchy fog in the Rolling Plains in the few hours
surrounding sunrise, where the western edge of the much deeper gulf
moisture advecting north into central plains encroaches our area. By
midday Monday temperatures will be back on the rise as moderate
southwest surface flow spreads across our CWA helping lift highs
into the 70s for most of us with our northwest zones in upper 60s.

The full-latitude upper level trough swinging across the inter-
mountain west Monday will emerge over the high plains Tuesday,
passing east Tuesday night. Height fields and surface pressure
gradients will tighten Tuesday, especially across the southern high
plains. Solutions in agreement again of 90+ knots of flow at the 500
millibar level Tuesday afternoon, with 50 to 55 knots of flow mixed
out within the 850 to 700 millibar layer. Strongest wind core seems
to show best from our southwest zones through central and towards
our northeast zones. Guidance winds also are higher, now from 32 to
38 knots at Lubbock Tuesday afternoon. We still are expecting
possibly a significant plume of high clouds to spread overhead, that
may delay deeper mixing somewhat, although forecast soundings are
not indicating any such problem with deep mixing by late morning or
midday on Tuesday.

A small amount of convective potential energy will expand eastward
late Tuesday and into the evening favoring northwest zones. Mid
levels may saturate with the wave passage and possibly generate
shallow high-based showers. We have added sprinkles for our
northwest counties. And elevated showers may assist as well in
downward momentum transfer of the strong winds aloft, though also
could increase relative humidity a bit above our current forecast.

We are issuing a high wind watch for Tuesday, and a corresponding
Fire Weather Watch (see the discussion on this below.)

A cold front will follow late Tuesday night and should be clearing
most of the area before daybreak Wednesday. Northerly breezes will
be strongest Wednesday across the Rolling Plains. Temperatures
Wednesday will fall a little below normal, and with lighter winds
Wednesday night should lead to widespread sub- freezing readings

The next energy from the eastern Pacific appears weak and will split
and dip south into a weak slow-moving upper trough crossing northern
Mexico over the weekend. We will see dry and a gradual warmup
Thursday into Saturday with modest windspeeds. A stronger Pacific
wave passing to the north may increase wind again Sunday before a
cold front early Monday, but solutions are inconclusive on how
strong the wave will be and whether main energy will cross in the
northern plains or the central plains. More on this later.

Fire weather concerns may become elevated across the southern South
Plains by mid-afternoon tomorrow. The airmass will be dry with most
of our area looking at RH values in the teens from mid-afternoon to
early evening with moderate southwest winds. Have decided to let
overnight shift reassess before issuing any products.

For Tuesday, a very strong deep layer of wind and tightened
height gradients will spread across the area in advance of an
upper trough expected to pass Tuesday night. This should lead to a
very windy day, and possibly wind gusts approaching 60 mph for
some areas. Solutions also are indicating high clouds early
Tuesday, and then an increase in mid level moistening. With deep
mixing, this may limit the relative humidity drop and make it
difficult to reach the required 15 percent level for Red Flag
conditions. However, relative humidity remains the trickiest part
of this forecast, downslope winds often lead to lower humidity
than expected, while the very strong wind speeds seem more
certain. Based mainly on confidence in the winds, we are issuing a
Fire Weather Watch Tuesday for nearly the entire area.

On Wednesday, a cold front will pass early in the day with breezy
northerly winds across the Rolling Plains. With very dry following
the front, it`s not impossible that we will have elevated fire
danger on Wednesday. RMcQueen


Fire Weather Watch from Tuesday morning through Tuesday evening
for TXZ021>043.

High Wind Watch from Tuesday morning through Tuesday evening for



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