Latest Seasonal Assessment -
Continued hot, dry weather will likely lead to an expansion of drought across eastern Texas during the latter part of June. Farther
south, some moisture may benefit South Texas, but no significant relief is forecast for the historical drought covering
south-central Texas. The odds for improvement increase in northern Texas, where prospects range from limited improvement to more
significant improvement. The best chance for improvement extends from western Texas into New Mexico. Above-normal rains are
forecast early in the period for this area, and the summer thunderstorm season that runs from July into September is expected to
offer additional relief. Shower activity is forecast to bring some improvement to the Oklahoma Panhandle, while small drought
areas in central Oklahoma are forecast to merge. In the West, unseasonable rains during the first half of June brought some
drought relief, especially for Oregon and Idaho. Although above-normal rains are forecast for the latter part of June over the
Northwest, amounts are expected to be less than observed earlier in the month, and the July-September period is typically not
favorable for drought relief. As a consequence, drought should largely persist from California and Nevada into southern Oregon.
The long-standing drought in northern Wisconsin and southeastern Minnesota is forecast to improve, thanks in part to heavy rains
forecast for the early stages of the forecast period. Drought in Hawaii is likely to continue to expand.
Tools used in the Drought Outlook included the
official CPC precipitation outlook for July 2009 and the long lead forecast for July – September 2009,
the four-month Palmer drought termination and amelioration probabilities, various medium- and
short-range forecasts and models such as the 6-10 day and 8-14 day forecasts, the soil
moisture tools based on the GFS model and the Constructed Analogue on Soil (CAS) moisture, the
Climate Forecast System (CFS) seasonal precipitation forecasts, and climatology.
In Wisconsin and Minnesota, the 5-day QPF for the start of the
forecast period depicted 1.5 to more than 2 inches of rain. CPC extended-range forecasts (6-10 and 8-14 days) indicated that
above-median rain was likely beyond the 5-day period. The CPC soil moisture models indicated a 20-40 mm reduction in the
deficits over the drought area by the end of week 2. These positive developments are enough to swing the Outlook from some
improvement to improvement despite continued uncertainty about the July-September precipitation outlook.
Forecast confidence for Wisconsin and Minnesota is moderate.
For Texas, the first half of June was unusually dry across southern
and eastern Texas into Louisiana. Houston reported a mere trace of rainfall from June 1-16, with temperatures mid-month rising
into the upper 90s. Hot, dry weather during the first 5 days of the forecast period is expected to exacerbate dryness, but a
wetter pattern for southern and eastern Texas is forecast for the extended-range forecasts. Above-normal rainfall is forecast
for Louisiana in the extended range. Drought is forecast to expand eastward in Texas, but the likelihood for significant rains
in Louisiana keeps the development area out of Louisiana. Model forecasts for the extended range indicate a surge northward of
moisture that could bring showers to Deep South Texas toward the end of June, so some improvement is indicated for this area,
expanded slightly to the west from the previous Outlook due mainly to the 2-week soil moisture forecasts. The bulk of the
drought area in south-central Texas is depicted to persist, as climatology suggests reduced odds for significant improvement
this time of the year. El Nino analogs played no more than a very minor role in this Outlook, given that impacts this time of
the year are generally considered minor, but it is noted that one of the 3-month soil model forecasts driven by historical El
Nino events shows increased odds for dryness in south-central Texas compared to all historical years. Also, the CFS model shows
enhanced odds for below-normal rainfall for southern Texas. Farther north, the Drought Outlook continues to indicate some
improvement for northern Texas, with improvement farther west. This is consistent with various seasonal precipitation and soil
moisture forecasts and is similar to the previous Outlook. The confidence for improvement over west Texas and into New Mexico
is relatively high, given consistency between short range and long-range precipitation forecasts. The official CPC
July-September precipitation outlook shows equal chances for wet, dry, or median for the southern Plains except for extreme
western Texas and Oklahoma.
Forecast confidence for southern, central, and eastern Texas is moderate. Confidence for West Texas is high.
The Outlook continues to show improvement for the Southwest, with
especially high expectations for improvement for the New Mexico area and adjacent Texas as a surge of moisture out of Mexico
was evident on satellite imagery at the time this Outlook was prepared. Given this initial rainfall, plus the typical
improvement from summer thunderstorms during July-September, prospects for improvement look favorable. The CPC official
seasonal outlook shows the odds tilting toward above-median rainfall across much of the Southwest, further adding to
confidence in the drought outlook.
Forecast confidence for the Southwest is high.
In far western Oklahoma, the odds for improvement increase toward
the west based on climatology and the seasonal rainfall outlook. Some improvement continues to be shown for the Panhandle. The
two small areas of drought in central Oklahoma are expected to persist based on short term and extended range forecasts showing
below-median rainfall and above-normal temperatures, as well as climatological considerations.
Confidence for Oklahoma is moderate.
This Outlook replaces the area of some improvement in northern
California, Oregon, and Idaho with persisting drought. Although an upper-level trough is expected to bring above-median
rainfall to much of the Northwest during the latter half of June, rainfall amounts are not expected to be as high as those
received earlier in June. In addition, the Outlook period covers the time of the year when drought improvement is unlikely.
Confidence in the Outlook is reduced because of the possibility that the short-term moisture could have more of an impact than
Forecast confidence for the West is moderate.
The area of drought shown for northern Washington continues to be
depicted as persisting. Extended-range forecasts indicate above-median rains, but actual rainfall amounts in the drought area
are expected to be light. In addition, the CPC long-lead monthly and seasonal outlooks show the odds leaning toward warmth and
dryness for Washington. To the east, above-median rainfall amounts are expected during the last half of June over Montana, and
some improvement is indicated for the small area in northern Montana due to favorable prospects for beneficial rains in the
short-term. The CPC long-lead outlooks depict the odds tilting toward below-normal rainfall for July and July-September,
reducing the likelihood for continued improvement.
Confidence for Washington and Montana is moderate.
The Outlook for the small drought area in southern Alaska is more
optimistic due to extended-range forecasts of above-median rainfall. With neither the CPC long-lead monthly nor seasonal
outlooks showing below-normal rainfall, the odds now favor improvement.
Forecast confidence for Alaska is moderate.
In Hawaii, with the dry season in progress, persisting and
expanding drought continues to be forecast. Below-normal rainfall is forecast for the extended range. Long-range forecasts are
more uncertain for this period, so the confidence in the drought outlook is not as high.
Forecast confidence for Hawaii is moderate.