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    NOAA Drought Outlook Monthly – July

    Photo: University of Illinois

    Drought conditions remain far more prevalent across the western CONUS than the East, though pockets of drought and more widespread abnormal dryness have expanded rapidly across the south-central CONUS, Mississippi Valley, central Corn Belt, and Southeast with unrelenting heat and generally below-average rainfall. Cooler temperatures and abundant precipitation eased drought conditions across the northern tier, while an early monsoon surge brought abundant convection and some flooding to parts of the Four Corners region in recent weeks.

    During July, above-average temperatures are favored across much of the CONUS, which will maintain high evapotranspiration rates during the climatologically hottest month of the year. Below-average precipitation is favored for much of the central US, including the Plains, mid-Mississippi Valley, and parts of the Corn Belt. This drier pattern, coupled with periods of heat, may promote further rapid drought development across parts of Texas, the lower and middle Mississippi Valley, southern Missouri, and the central Corn Belt.

    Drought expansion is also possible across the Plains in regions where soil moisture remains fairly low. More generous rainfall in the short term may preclude widespread drought development across the upper-Midwest, though the region is primed for potential drought development, which may occur in any areas that miss out on the convective precipitation.

    Across the rapidly drying Southeast, climatological summer convection may help to stave off further drought expansion, but is unlikely to be sufficient enough to improve the situation away from the immediate Atlantic Coast. Areas of short term drought continue to expand across coastal New England, with climatological precipitation during July unlikely to be sufficient to yield substantial improvements. A slightly wetter outlook across southern New England makes drought removal more likely for Connecticut and Rhode Island.

    Outside of the CONUS, drought conditions continued to expand across Alaska, and despite a more favorable precipitation outlook for July, warm temperatures and near constant sunlight will likely make the drought impacts intractable during July. Climatological dryness favors drought persistence and possible expansion across Hawaii, while the absence of a clear wet signal across Puerto Rico makes drought persistence the most likely outcome.

    United States Monthly Drought Outlook Graphic - click on image to enlarge

    Click Image to Enlarge

    Forecast confidence is high for the Western Region.

    • Drought conditions remain entrenched across the majority of the Western Climate Region, with just over 76 percent coverage of moderate drought (D1 depiction) or worse as of the June 28 U.S. Drought Monitor (USDM).
    • Drought coverage did drop somewhat over the past 4 weeks, however, as cool conditions and periods of heavy rainfall brought substantial improvements to the Northwest and Northern Rockies, decreasing the overall coverage of drought over the past 4 weeks.
    • More recently, widespread heavy rainfall associated with an early monsoon surge brought some drought relief and localized flooding to the Four Corners region. In contrast, climatologically dry conditions yielded no relief for California and the Great Basin.
    • Locally heavy convective precipitation is favored to continue across the Four Corners region during early June in association with the monsoon, which, coupled with continued absorption of recent rainfall into groundwater and streams, favors additional drought amelioration across Arizona, New Mexico, far southern Utah, and Colorado.
    • Climatology strongly favors persistence for California and the Great Basin, while equal chances (EC) for below-, near-, and above-average precipitation across the Northwest favors status quo, with near to above-average streamflows limiting potential for drought redevelopment and no clear signal for additional reductions.

    Forecast confidence is moderate for the High Plains Region.

    • Drought impacts currently cover just over half of the High Plains Climate Region.
    • During the past four weeks, periods of organized convection brought drought relief to multiple portions of the Plains, though hot weather promoted some drought expansion across southeastern Wyoming, northeastern Colorado, western Kansas, and Nebraska, which missed out on the heavier rainfall. Soil moisture conditions are favorable across the Northern Tier and eastern Kansas, which should limit the potential for drought development during July.
    • Anticipated high temperatures and near to below-average rainfall, however, will make regions that are already drying out vulnerable to rapid drought development.
    • Based on short and medium range guidance as well as the updated CPC temperature and precipitation outlooks, drought persistence is favored across the High Plains region, with additional development possible across parts of Colorado, Nebraska, southwestern South Dakota, and central Kansas.

    Forecast confidence is high for the Southern Region.

    • During the past four weeks, widespread heavy rainfall ameliorated drought conditions somewhat across North Texas and central Oklahoma, while below-average rainfall and periods of excessive heat promoted rapid expansion of drought and abnormal dryness (D0) across eastern Texas, Louisiana, and parts of Arkansas.
    • Over the next several days, a disorganized tropical disturbance may briefly organize into a tropical depression just offshore of Texas, bringing widespread heavy rainfall to the western Gulf Coast. Short term drought improvements are therefore likely across coastal Southeast Texas and southern Louisiana.
    • Outside of the regions impacted by this disturbance, dry antecedent conditions across northeastern Texas, northern Louisiana, and along the lower- to mid-Mississippi Valley have made these regions highly vulnerable to drought development.
    • The updated CPC July precipitation outlook favors enhanced chances for below-average precipitation, coupled with enhanced chances for above-average temperatures. Therefore, further rapid expansion of drought into areas where soil moisture is already low is strongly favored.

    Forecast confidence is low to moderate for the Midwest Region.

    • As of June 28, only 7 percent of the Midwest Climate Region was experiencing drought impacts; however, periods of hot weather and generally below-average precipitation promoted substantial decreases in soil moisture content. These antecedent conditions, coupled with high evapotranspiration requirements across the Corn Belt, have resulted in considerable vulnerability to drought development across the entire region.
    • Over the next 7 days, widespread heavy rainfall is favored across northern Missouri, Iowa, and the upper Mississippi Valley, while EC is maintained for precipitation on the updated July outlook from CPC. This may be enough to limit drought expansion during July; however, spotty development is possible across areas that miss out on convective precipitation.
    • More widespread drought development is likely across southern Missouri, Kentucky, and parts of Illinois, where the CPC monthly outlooks favor above-average temperatures and below-average rainfall.
    • While EC is maintained across Indiana, favored above-average temperatures and drying soils make even climatological precipitation unlikely to stave off further degradations. Therefore, drought development is favored across much of Indiana as well.

    Forecast confidence is moderate for the Southeast Region.

    • As discussed in the Seasonal Drought Outlook narratives released on June 16, flash drought conditions have materialized across much of the Piedmont region of the Southeast, while longer term drought conditions persisted and expanded along the South Atlantic Coast.
    • While removal was favored on the seasonal outlook, these drought conditions are likely to remain largely entrenched throughout July, with some further localized expansions possible in regions that miss out on convective thunderstorms.
    • The 7-day QPF from WPC depicts fairly generous rainfall across the Southeast, with a strip of drier conditions possible along the high piedmont and Blue Ridge. This short term precipitation may help limit widespread degradation, but is unlikely to spark much improvement.
    • The updated July outlook from CPC maintains a slight tilt towards above-average precipitation, but in the face of enhanced chances for above-average temperatures and absent a stronger wet signal, persistence is the most likely outcome. The exception to this is the immediate Atlantic coast, where widespread heavy rainfall is favored during early June, which may provide an opportunity for some drought relief.

    Forecast confidence is low to moderate for the Northeast Region.

    • Areas of moderate drought have persisted and expanded somewhat across portions of coastal New England, with streamflow values remaining low and meager precipitation failing to overcome the high evapotranspiration rates despite fairly cool temperatures and a period of heavier showers across southern New England.
    • The updated July precipitation outlook from CPC maintains EC across much of New England, with a slight tilt towards above-average rainfall across Connecticut and Rhode Island. Above-average temperatures are favored during July, which will maintain high evapotranspiration rates.
    • Based on these outlooks, drought persistence is the most likely outcome for Maine and Massachusetts, with the greatest potential for relief extending across Connecticut and Rhode Island. There is even a chance for further drought expansion across southwestern Maine, though confidence is too low to indicate a region on this outlook.

    Forecast confidence is high for Hawaii, and moderate for Alaska and Puerto Rico.

    • Dynamical model forecasts do not depict a significant deviation from a climatologically dry pattern across Hawaii. Therefore, drought persistence is favored, with some expansion possible across the more rain-shadowed portions of the Big Island.
    • Drought conditions have expanded across Alaska following a poor snowmelt season and periods of above-average temperatures. Despite a shift towards enhanced chances for above-average precipitation across some of the Alaska drought areas, almost constant sunshine during July makes substantial drought relief more difficult to achieve. Therefore, drought persistence appears to be the most likely outcome.
    • Drought persistence is also favored across Puerto Rico, absent a clear wet signal in the dynamical model guidance.



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