Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 325 AM EDT Sun Jun 17 2018 Valid Jun 17/0000 UTC thru Jun 20/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model evaluation including preferences and forecast confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Oblong closed low over the Western United States moving northeast day 3 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~ Preference: 17/00Z GFS and 16/12Z ECMWF throughout the period Confidence: Above average until 19/00z...average thereafter The 00Z suite of NCEP guidance generally held the course with their previous idea of having an oblong shaped closed low initially over the Western United States. The GFS still depicts the eastern lobe of this system getting pulled northeast while the western lobe drops into the Northern Great Basin late Sunday/Monday. This entire system finally gets nudged east and northeast as the axis of upstream ridging approaches the west coast of North America. Between having rising mid level heights on its west and south at the same time that the closed low is weakening and beginning to open, the system will begin to head northeast as it weakens. The GFS and ECMWF still seemed to be forming the strongest alliance in terms of run to run consistency and in terms of the agreement in their mass fields. The 00Z GfS was not quite the northern outlier that it had been during the 16/12Z run. The NAM and UKMET looked to be outliers. The 00Z non-NCEP models also tended to keep close to their previous solutions. The UKMET and CMC were a bit faster than the NCEP guidance in exiting whatever remains of the low...with the ECMWF being a bit faster that previous runs. This leaves a compromise of the 00Z GFS/ECWMF may be best. ...Shearing energy and broad mid-level kicker shortwave lifting northward in confluent flow... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Average Goes WV suite depicts the main shortwave core of what had been TC Bud over western/central NM early this moring with a broad cyclonically curved kicker wave over northern Baja California. The deterministic guidance are falling in line with typical biases but with only smaller differences in impacts mainly in timing. The 00Zz NAM/GFS/UKMET remained fast with the remains of Bud lifting into the Dakotas. This feature and the upstream kicker eventually enter confluent mid-level flow and shear as they enter into confluent flow at the trailing edge of a Canadian trof (see section below) and accelerate into the northeast by Tues/Wed. While there is some small differences in depth and timing, there is no discernible model trend/ensemble support for one solution over another, as such a general model blend could be supported for these waves. ...Broad TUTT Cell and low level easterly tropical wave progressing through Western Gulf with high moisture flux possible surface low in NE Mexico/Southern Plains by Late Mon to Wed... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: 17/00Z GFS/ECMWF blend Confidence: Below average Goes-16 WV imagery still shows a forming broad TUTT cell over the SW Gulf/Bay of Campeche but also a strong convective response along the eastern coast of the Yucatan peninsula associated with a downstream tropical easterly wave. Cycle to cycle ensemble continue to show a fairly uncertain development path for these features and appear highly contingent on the strength of the convective complex to generate (or not) a MCV response. Regardless, nearly all the models show a gap between two subtropical highs...one over the eastern North Pacific and the other located over the Southeast U.S....there is a path the system can follow into the Western Gulf. Given the uncertainty on the evolution and dynamics, will continue to favor an ECMWF blend with below average confidence.The 17/00Z UKMET looks to be a strong outlier while the Canadian takes the system inland much farther than other global guidance. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Bann