Adding The East for Heavy Rain Next Week?
04/29/2025, 4:32 pm EDT
Fig. 1-2: The convection phase of the Madden Julian oscillation is vividly visible in the tropical East Pacific Ocean and the catalyst for an ongoing wet pattern in the U.S.
Discussion: The convection phase of the Madden Julian oscillation (MJO) centered near and west of the Dateline in April, developed an eastward extension during the past 10 days resting in the eastern tropical North Pacific (Fig. 1). The emergence of this feature is the catalyst to the heavy rains centered on Texas and the southern Great Plains in late April. MJO forecasts indicate a stagnant (MJO) pattern for the first 1-2 weeks of May. Consequently, the energetic tropical influence from the tropical East Pacific into the U.S. weather pattern continues and the 15-day forecast indicates widespread above normal rainfall for the Southwest, South, and Mid-Atlantic States (Fig. 2). North of the wet belt, the Midwest States stay dry.
In Europe, a new negative phase of the Scandinavia index (-SCAND) is developing and forecast to last to mid-May (Fig. 3). SCAND has been active so far in 2025 as negative phase has brought significant troughs to Northern Europe and Southwest Russia while positive phase has spawned amplified upper ridge patterns over Northwest Eurasia and Southeast Europe. The new -SCAND pattern will cool Europe and bring a 2-week rainy pattern to Spain, Italy, and northeastward to Southwest Russia (Fig. 4). Hopefully, the wet weather will help ease, at least slightly, ongoing vigorous drought in Southeast Europe to Southwest Russia (Fig. 5). Forecast models vary on whether the Black Sea region receives much rainfall. The drought pattern is ongoing and intensifying across much of Europe to Southwest Russia inspired by below normal precipitation through the past 90 days (Fig. 6).
Fig. 3: The 15-day Scandinavia index forecast and 120 days of history back to January 1st identifying significant ridge/trough patterns affecting Europe climate.
Fig. 4-6: The ECM ENS 15-day percent of normal rainfall forecast across Europe, the daily soil moisture anomalies analysis, and 90-day percent of normal precipitation observations across Europe.