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Stacy R. Stewart and Steven W. Lyons

. Forecasters at Andersen Air Force Baseused this information to give what turned out to be a very accurate short-range forecast of a brief period ofgales with maximum gusts to 26 m s0 1 . Land-based surface wind observations correlated extremely well with75%- 80% of the 1500-m radial velocity estimates, which is similar to findings made by Powell and Tanneret al. Additional radar signatures of interest include offsets between the reflectivity center and velocity cir-culation center, detection of tropical

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Hui-Ling Chang, Barbara G. Brown, Pao-Shin Chu, Yu-Chieng Liou, and Wen-Ho Wang

in the presence of dominant thermal forcing. Lin et al. (2012) found that the best predictors of afternoon thunderstorms were vapor pressure, humidity, wind direction, and wind speed of the boundary layer in the morning, as well as CAPE, dewpoint depression ( T − T d ), wind direction, and wind speed in the lower–middle layer of the troposphere (1000–500 hPa) from sounding data at 0800 local standard time (LST). The use of high-resolution ensemble forecasts to predict CI is currently still

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Gary P. Ellrod and David I. Knapp

150 WEATHER AND FORECASTING VOLUME7FORECASTING TECHNIQUESAn Objective Clear-Air Turbulence Forecasting Technique: Verification and Operational Use GARY P. ELLRODSatellite Applications Laboratory (NOAA/NESDIS), Washington, D.C. DAVID I. KNAPPAir Force Global Weather Central (AFGWC), Offutt Air Force Base, Nebraska6 June 1991 and 12 September 1991 An objective technique for forecasting clear

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Xu Zhang, Yuhua Yang, Baode Chen, and Wei Huang

(2004) reported that heavy rainfall over the Korean Peninsula is mainly organized by strong synoptic-scale forcing. In this weather regime, the mechanisms responsible for heavy precipitation are different from precipitation over the central United States, which is produced by mesoscale convective systems. Over the United States, the role of parameterized convection is crucial to simulations of mesoscale properties and precipitation forecasting. However, CPS plays an insignificant role in the

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David R. Bright and Steven L. Mullen

). The weak synoptic-scale forcing for upward vertical motion combined with large areas void of conventional surface and upper-air observations ( McCollum et al. 1995 ) decreases NWP skill during the monsoon. Junker et al. (1992) report that, for precipitation events exceeding 6 mm, the NCEP Nested Grid Model (NGM; Hoke et al. 1989 ) and Medium-Range Forecast Model (MRF; Kanamitsu et al. 1991 ) exhibit their lowest forecast skill in the southwestern United States. Likewise, Dunn and Horel (1994a

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Erik R. Nielsen, Gregory R. Herman, Robert C. Tournay, John M. Peters, and Russ S. Schumacher

the cold or warm season were associated with large-scale synoptic forcing (e.g., a cold front) and were characterized as such. However, events featuring the upscale growth of convection from discrete cells to a more organized MCS structure were classified separately. If at any point within 3 h following the verified TORFF event the responsible storm could be identified as one of the MCS archetypes, it was classified as transitioning. This category represents verified TORFF events that occur

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Ariel E. Cohen and John P. Cangialosi

gaps. In autumn 2008, forecasters were surprised a number of times when a ship meandering in the northern gulf reported northwest to north surface winds over gale force while all global model guidance was depicting 10-m winds no higher than 25 kt (12.9 m s −1 ). Forecasters investigated these observations and found that they originated from the NOAA Research Vessel (R/V) David Starr Jordan , whose primary mission was to study the biological and physical oceanography of the Gulf of California in

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Dorita Rostkier-Edelstein and Joshua P. Hacker

results showed that with initialization and forcing distributions chosen based only on the local time of day, it is possible to obtain estimates in the lowest few-hundred meters in the atmosphere. The accuracy approached observation-error levels. We extend that work to more challenging measures of skill, and quantify the importance of model improvements versus data assimilation when using the model to make 30-min predictions. Although it is appealing to add additional physics and dynamics to the SCM

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Ray Bell and Ben Kirtman

. Atlantic SST has also shown to be predictable on seasonal time scales ( Rodwell and Folland 2002 ), such as in the North Atlantic subpolar gyre. While it is important to understand and predict the physical mechanisms forcing the NAO ( Scaife et al. 2016 ), the role of ensembles and multimodel forecasts increases the skill of forecasting the NAO. Figure 3 in Scaife et al. (2014) shows that increasing the number of ensembles increases the correlation of the ensemble-mean forecast with the observed NAO

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Morris L. Weisman, Christopher Davis, Wei Wang, Kevin W. Manning, and Joseph B. Klemp

131 days, with strong disagreement on only 11 of the 232 days considered ( Table 4c ). This suggests that the convection in the 4-km ARW model was strongly tied to the forcing features resolved in the Eta Model. An example of such strong correspondence was previously presented in Figs. 8 and 9 , where both ARW and Eta correctly forecast convection in Nebraska but incorrectly forecast convection in southwest Oklahoma and Missouri. Similarly, the 10 June 2003 ( Figs. 3 and 5 ) and 5 June 2005

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