WMOD00176

• Project Name: Annual Report
• Title: Seeding Operations & Atmospheric Research, 2005 Annual Report
• Prepared By: Duncan Axisia
• Date: 12/31/2005
• Weather Modification - Doc Type: Report

thunderstorms dropped over 5" of rain in
Brownfield, TX and due to excessive rainfall in
the region. Yoakum County officials asked the
SOAR program to cease operational seeding
until June 6th in the Southern Ogaiiaia (Texas)
target areas.

June 2005

June began much as it has ended, with high
pressure over west Texas. On the 3rd, an
upper level low formed over the Rockies along
with a surface low over the Central Plains. A
shortwave at 500mb moved through west
Texas during the day triggering thunderstorms
to our east near the caprock. A dry southwest
wind prevented any convective activity in our
area. By the 5th high pressure had built back
in over west Texas and this would become a
reoccurring theme by the middle of the
month. A surface low over the panhandle
developed on the 8th but the dryline surged
eastward as a result of strong westerly flow
aloft and left the Southern Ogallala target
area without any rainfall. On the 10th a
surface low over the central plains states
extended a frontal boundary through west
Texas. With moderate southeast flow at the
surface we saw convection develop in the
northern portion of the Southern Ogallala
target area. This boundary presented our first
opportunity for a seeding mission in June.
With tropical storm Arlene in the Gulf of
Mexico on the 11 th the low over the central
plains began to back up and deepen causing
the frontal boundary to stall over west Texas.
Isolated thunderstorms developed over the
northeastern quadrant of the Southern
Ogallala target area. We launched our second
operation of the month. With Arlene now
coming inland and moving on a northerly
track through the lower Mississippi valley, the
low over the central plains and the associated
cold front still had no place to go. On the 12th
with southeast flow at 850mb and the stalled
frontal boundary showers and isolated
thunderstorms developed early in the
afternoon over the eastern peripheral of the
Southern Ogallala target area. A
reconnaissance flight was launched but the
cell had weakened significantly and moved
out of the area by the time the seeding
aircraft reached the area.

By the 13th high pressure moved in from the
pacific northwest and seemed to establish
itself for good over west Texas. With a strong
upper level ridge and surface high pressure,
temperatures began their rnarch toward
100oF. Not much changed in the week that
followed and by the 20th the high pressure was
still the story although temperatures had
moderated back down to seasonal norms in
the low 90's. Mostly sunny skies were
observed through the week until the morning
of the 26th. An abundance of low-level
moisture provided by moderate southeast
flow at 850mb and an area of convergence as
a result of convection from the mountains in
New Mexico helped initiate showers and
isolated thunderstorms in the Southern
Ogallala target area. A reconnaissance flight
deemed the cloud bases too high and
fragmented so no seeding was attempted. On
the 27th an upper level ridge was back in
control of our weather. With an upper level
trough over the southwest riding the ridgeline
to our north over the central plains, west
Texas soon was under the influence of a dry
westerly zonal flow aloft. With no significant
surface features to help initiate convection
the Southern Ogallala area was dry for the
remainder of the month.

.
.
.
.
.
.

July 2005

.-.
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

The Southern Ogallala target area began July
with temperatures at 100oF. With an upper
level ridge situated over the southwest
portion of the country and a surface boundary
extending into the northern Texas panhandle
with a low level jet (LU) out of the southeast
the atmosphere was suitably unstable to
expect convective development on the 1 st.
When convection initiated The Southern
Ogallala program launched its first mission of
the month. With broadening high pressure in
the northeast and a strong low forming in the
northern central plains the polar jet to our
north was in a zonal flow pattern. This
effectively cut west Texas and eastern New
Mexico off from any developing surface
features to initiate convective clouds. By the
4th, a weak trough in the upper level flow
developed helping initiate the development of
a surface Low over the Great Lakes. A frontal
boundary from this system extended through
west Texas and slowly translated south as
high pressure built into the central plains.

10